| blob | d02d564883ae2a00366855098df2a52b38f7b1f5 |
1 /*-------------------------------------------------------------------------
2 *
3 * tablecmds.c
4 * Commands for creating and altering table structures and settings
5 *
6 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 *
10 * IDENTIFICATION
11 * src/backend/commands/tablecmds.c
12 *
13 *-------------------------------------------------------------------------
14 */
112 /*
113 * ON COMMIT action list
114 */
116 {
120 /*
121 * If this entry was created during the current transaction,
122 * creating_subid is the ID of the creating subxact; if created in a prior
123 * transaction, creating_subid is zero. If deleted during the current
124 * transaction, deleting_subid is the ID of the deleting subxact; if no
125 * deletion request is pending, deleting_subid is zero.
126 */
127 SubTransactionId creating_subid;
128 SubTransactionId deleting_subid;
134 /*
135 * State information for ALTER TABLE
136 *
137 * The pending-work queue for an ALTER TABLE is a List of AlteredTableInfo
138 * structs, one for each table modified by the operation (the named table
139 * plus any child tables that are affected). We save lists of subcommands
140 * to apply to this table (possibly modified by parse transformation steps);
141 * these lists will be executed in Phase 2. If a Phase 3 step is needed,
142 * necessary information is stored in the constraints and newvals lists.
143 *
144 * Phase 2 is divided into multiple passes; subcommands are executed in
145 * a pass determined by subcommand type.
146 */
149 {
157 /* We could support a RENAME COLUMN pass here, but not currently used */
166 #define AT_NUM_PASSES (AT_PASS_MISC + 1)
169 {
170 /* Information saved before any work commences: */
175 /*
176 * Transiently set during Phase 2, normally set to NULL.
177 *
178 * ATRewriteCatalogs sets this when it starts, and closes when ATExecCmd
179 * returns control. This can be exploited by ATExecCmd subroutines to
180 * close/reopen across transaction boundaries.
181 */
182 Relation rel;
184 /* Information saved by Phase 1 for Phase 2: */
186 /* Information saved by Phases 1/2 for Phase 3: */
194 * if above is true */
199 /* true, if validating default due to some other attach/detach */
201 /* Objects to rebuild after completing ALTER TYPE operations */
212 /* Struct describing one new constraint to check in Phase 3 scan */
213 /* Note: new not-null constraints are handled elsewhere */
215 {
226 /*
227 * Struct describing one new column value that needs to be computed during
228 * Phase 3 copy (this could be either a new column with a non-null default, or
229 * a column that we're changing the type of). Columns without such an entry
230 * are just copied from the old table during ATRewriteTable. Note that the
231 * expr is an expression over *old* table values, except when is_generated
232 * is true; then it is an expression over columns of the *new* tuple.
233 */
235 {
242 /*
243 * Error-reporting support for RemoveRelations
244 */
245 struct dropmsgstrings
246 {
253 };
257 ERRCODE_UNDEFINED_TABLE,
263 ERRCODE_UNDEFINED_TABLE,
269 ERRCODE_UNDEFINED_TABLE,
275 ERRCODE_UNDEFINED_TABLE,
281 ERRCODE_UNDEFINED_OBJECT,
287 ERRCODE_UNDEFINED_OBJECT,
293 ERRCODE_UNDEFINED_OBJECT,
299 ERRCODE_UNDEFINED_TABLE,
305 ERRCODE_UNDEFINED_OBJECT,
311 };
313 /* communication between RemoveRelations and RangeVarCallbackForDropRelation */
314 struct DropRelationCallbackState
315 {
316 /* These fields are set by RemoveRelations: */
318 LOCKMODE heap_lockmode;
319 /* These fields are state to track which subsidiary locks are held: */
320 Oid heapOid;
321 Oid partParentOid;
322 /* These fields are passed back by RangeVarCallbackForDropRelation: */
325 };
327 /* Alter table target-type flags for ATSimplePermissions */
328 #define ATT_TABLE 0x0001
329 #define ATT_VIEW 0x0002
330 #define ATT_MATVIEW 0x0004
331 #define ATT_INDEX 0x0008
332 #define ATT_COMPOSITE_TYPE 0x0010
333 #define ATT_FOREIGN_TABLE 0x0020
334 #define ATT_PARTITIONED_INDEX 0x0040
335 #define ATT_SEQUENCE 0x0080
336 #define ATT_PARTITIONED_TABLE 0x0100
338 /*
339 * ForeignTruncateInfo
340 *
341 * Information related to truncation of foreign tables. This is used for
342 * the elements in a hash table. It uses the server OID as lookup key,
343 * and includes a per-server list of all foreign tables involved in the
344 * truncation.
345 */
347 {
348 Oid serverid;
352 /* Partial or complete FK creation in addFkConstraint() */
354 {
355 addFkReferencedSide,
356 addFkReferencingSide,
357 addFkBothSides,
360 /*
361 * Partition tables are expected to be dropped when the parent partitioned
362 * table gets dropped. Hence for partitioning we use AUTO dependency.
363 * Otherwise, for regular inheritance use NORMAL dependency.
364 */
365 #define child_dependency_type(child_is_partition) \
366 ((child_is_partition) ? DEPENDENCY_AUTO : DEPENDENCY_NORMAL)
376 static List *MergeCheckConstraint(List *constraints, const char *name, Node *expr, bool is_enforced);
377 static void MergeChildAttribute(List *inh_columns, int exist_attno, int newcol_attno, const ColumnDef *newdef);
378 static ColumnDef *MergeInheritedAttribute(List *inh_columns, int exist_attno, const ColumnDef *newdef);
379 static void MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispartition);
391 LOCKMODE lockmode);
396 LOCKMODE lockmode);
431 AlterTablePass cur_pass,
444 LOCKMODE lockmode,
447 DropBehavior behavior);
461 LOCKMODE lockmode);
463 LOCKMODE lockmode);
467 LOCKMODE lockmode);
479 static ObjectAddress ATExecDropIdentity(Relation rel, const char *colName, bool missing_ok, LOCKMODE lockmode,
481 static ObjectAddress ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
483 static void ATPrepDropExpression(Relation rel, AlterTableCmd *cmd, bool recurse, bool recursing, LOCKMODE lockmode);
484 static ObjectAddress ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMODE lockmode);
495 DropBehavior behavior,
509 LOCKMODE lockmode);
517 LOCKMODE lockmode);
521 LOCKMODE lockmode);
529 Oid parentConstr,
552 Relation partitionRel);
555 Relation partRel);
558 Oid indexOid,
563 Oid indexOid,
567 Oid partRelid,
571 Oid parentInsTrigger,
572 Oid parentUpdTrigger,
573 Relation trigrel);
603 LOCKMODE lockmode);
619 LOCKMODE lockmode);
630 AlterTableType operation,
631 LOCKMODE lockmode);
634 LOCKMODE lockmode);
641 DependencyType deptype);
659 static void ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNumber *partattrs,
661 PartitionStrategy strategy);
685 Relation partitionTbl);
693 /* ----------------------------------------------------------------
694 * DefineRelation
695 * Creates a new relation.
696 *
697 * stmt carries parsetree information from an ordinary CREATE TABLE statement.
698 * The other arguments are used to extend the behavior for other cases:
699 * relkind: relkind to assign to the new relation
700 * ownerId: if not InvalidOid, use this as the new relation's owner.
701 * typaddress: if not null, it's set to the pg_type entry's address.
702 * queryString: for error reporting
703 *
704 * Note that permissions checks are done against current user regardless of
705 * ownerId. A nonzero ownerId is used when someone is creating a relation
706 * "on behalf of" someone else, so we still want to see that the current user
707 * has permissions to do it.
708 *
709 * If successful, returns the address of the new relation.
710 * ----------------------------------------------------------------
711 */
712 ObjectAddress
715 {
717 Oid namespaceId;
718 Oid relationId;
719 Oid tablespaceId;
720 Relation rel;
721 TupleDesc descriptor;
728 Datum reloptions;
730 AttrNumber attnum;
733 Oid ofTypeId;
734 ObjectAddress address;
735 LOCKMODE parentLockmode;
738 /*
739 * Truncate relname to appropriate length (probably a waste of time, as
740 * parser should have done this already).
741 */
744 /*
745 * Check consistency of arguments
746 */
754 {
760 }
761 else
770 /*
771 * Look up the namespace in which we are supposed to create the relation,
772 * check we have permission to create there, lock it against concurrent
773 * drop, and mark stmt->relation as RELPERSISTENCE_TEMP if a temporary
774 * namespace is selected.
775 */
776 namespaceId =
779 /*
780 * Security check: disallow creating temp tables from security-restricted
781 * code. This is needed because calling code might not expect untrusted
782 * tables to appear in pg_temp at the front of its search path.
783 */
790 /*
791 * Determine the lockmode to use when scanning parents. A self-exclusive
792 * lock is needed here.
793 *
794 * For regular inheritance, if two backends attempt to add children to the
795 * same parent simultaneously, and that parent has no pre-existing
796 * children, then both will attempt to update the parent's relhassubclass
797 * field, leading to a "tuple concurrently updated" error. Also, this
798 * interlocks against a concurrent ANALYZE on the parent table, which
799 * might otherwise be attempting to clear the parent's relhassubclass
800 * field, if its previous children were recently dropped.
801 *
802 * If the child table is a partition, then we instead grab an exclusive
803 * lock on the parent because its partition descriptor will be changed by
804 * addition of the new partition.
805 */
807 ShareUpdateExclusiveLock);
809 /* Determine the list of OIDs of the parents. */
812 {
814 Oid parentOid;
818 /*
819 * Reject duplications in the list of parents.
820 */
828 }
830 /*
831 * Select tablespace to use: an explicitly indicated one, or (in the case
832 * of a partitioned table) the parent's, if it has one.
833 */
835 {
842 }
844 {
847 }
848 else
851 /* still nothing? use the default */
854 partitioned);
856 /* Check permissions except when using database's default */
858 {
859 AclResult aclresult;
862 ACL_CREATE);
866 }
868 /* In all cases disallow placing user relations in pg_global */
874 /* Identify user ID that will own the table */
878 /*
879 * Parse and validate reloptions, if any.
880 */
885 {
894 }
897 {
898 AclResult aclresult;
905 }
906 else
909 /*
910 * Look up inheritance ancestors and generate relation schema, including
911 * inherited attributes. (Note that stmt->tableElts is destructively
912 * modified by MergeAttributes.)
913 */
920 /*
921 * Create a tuple descriptor from the relation schema. Note that this
922 * deals with column names, types, and in-descriptor NOT NULL flags, but
923 * not default values, NOT NULL or CHECK constraints; we handle those
924 * below.
925 */
928 /*
929 * Find columns with default values and prepare for insertion of the
930 * defaults. Pre-cooked (that is, inherited) defaults go into a list of
931 * CookedConstraint structs that we'll pass to heap_create_with_catalog,
932 * while raw defaults go into a list of RawColumnDefault structs that will
933 * be processed by AddRelationNewConstraints. (We can't deal with raw
934 * expressions until we can do transformExpr.)
935 *
936 * We can set the atthasdef flags now in the tuple descriptor; this just
937 * saves StoreAttrDefault from having to do an immediate update of the
938 * pg_attribute rows.
939 */
945 {
947 Form_pg_attribute attr;
949 attnum++;
953 {
965 }
967 {
983 }
986 }
988 /*
989 * For relations with table AM and partitioned tables, select access
990 * method to use: an explicitly indicated one, or (in the case of a
991 * partitioned table) the parent's, if it has one.
992 */
994 {
997 }
999 {
1001 {
1004 }
1008 }
1010 /*
1011 * Create the relation. Inherited defaults and CHECK constraints are
1012 * passed in for immediate handling --- since they don't need parsing,
1013 * they can be stored immediately.
1014 */
1016 namespaceId,
1017 tablespaceId,
1018 InvalidOid,
1019 InvalidOid,
1020 ofTypeId,
1021 ownerId,
1022 accessMethodId,
1023 descriptor,
1025 old_constraints),
1026 relkind,
1031 reloptions,
1033 allowSystemTableMods,
1035 InvalidOid,
1036 typaddress);
1038 /*
1039 * We must bump the command counter to make the newly-created relation
1040 * tuple visible for opening.
1041 */
1044 /*
1045 * Open the new relation and acquire exclusive lock on it. This isn't
1046 * really necessary for locking out other backends (since they can't see
1047 * the new rel anyway until we commit), but it keeps the lock manager from
1048 * complaining about deadlock risks.
1049 */
1052 /*
1053 * Now add any newly specified column default and generation expressions
1054 * to the new relation. These are passed to us in the form of raw
1055 * parsetrees; we need to transform them to executable expression trees
1056 * before they can be added. The most convenient way to do that is to
1057 * apply the parser's transformExpr routine, but transformExpr doesn't
1058 * work unless we have a pre-existing relation. So, the transformation has
1059 * to be postponed to this final step of CREATE TABLE.
1060 *
1061 * This needs to be before processing the partitioning clauses because
1062 * those could refer to generated columns.
1063 */
1068 /*
1069 * Make column generation expressions visible for use by partitioning.
1070 */
1073 /* Process and store partition bound, if any. */
1075 {
1079 defaultPartOid;
1080 Relation parent,
1084 /* Already have strong enough lock on the parent */
1087 /*
1088 * We are going to try to validate the partition bound specification
1089 * against the partition key of parentRel, so it better have one.
1090 */
1097 /*
1098 * The partition constraint of the default partition depends on the
1099 * partition bounds of every other partition. It is possible that
1100 * another backend might be about to execute a query on the default
1101 * partition table, and that the query relies on previously cached
1102 * default partition constraints. We must therefore take a table lock
1103 * strong enough to prevent all queries on the default partition from
1104 * proceeding until we commit and send out a shared-cache-inval notice
1105 * that will make them update their index lists.
1106 *
1107 * Order of locking: The relation being added won't be visible to
1108 * other backends until it is committed, hence here in
1109 * DefineRelation() the order of locking the default partition and the
1110 * relation being added does not matter. But at all other places we
1111 * need to lock the default relation before we lock the relation being
1112 * added or removed i.e. we should take the lock in same order at all
1113 * the places such that lock parent, lock default partition and then
1114 * lock the partition so as to avoid a deadlock.
1115 */
1116 defaultPartOid =
1122 /* Transform the bound values */
1126 /*
1127 * Add an nsitem containing this relation, so that transformExpr
1128 * called on partition bound expressions is able to report errors
1129 * using a proper context.
1130 */
1137 /*
1138 * Check first that the new partition's bound is valid and does not
1139 * overlap with any of existing partitions of the parent.
1140 */
1143 /*
1144 * If the default partition exists, its partition constraints will
1145 * change after the addition of this new partition such that it won't
1146 * allow any row that qualifies for this new partition. So, check that
1147 * the existing data in the default partition satisfies the constraint
1148 * as it will exist after adding this partition.
1149 */
1151 {
1153 /* Keep the lock until commit. */
1155 }
1157 /* Update the pg_class entry. */
1161 }
1163 /* Store inheritance information for new rel. */
1166 /*
1167 * Process the partitioning specification (if any) and store the partition
1168 * key information into the catalog.
1169 */
1171 {
1184 /* Protect fixed-size arrays here and in executor */
1189 PARTITION_MAX_KEYS)));
1191 /*
1192 * We need to transform the raw parsetrees corresponding to partition
1193 * expressions into executable expression trees. Like column defaults
1194 * and CHECK constraints, we could not have done the transformation
1195 * earlier.
1196 */
1204 partexprs,
1207 /* make it all visible */
1209 }
1211 /*
1212 * If we're creating a partition, create now all the indexes, triggers,
1213 * FKs defined in the parent.
1214 *
1215 * We can't do it earlier, because DefineIndex wants to know the partition
1216 * key which we just stored.
1217 */
1219 {
1221 Relation parent;
1225 /* Already have strong enough lock on the parent */
1229 /*
1230 * For each index in the parent table, create one in the partition
1231 */
1233 {
1237 Oid constraintOid;
1240 {
1248 else
1249 {
1252 }
1253 }
1258 idxstmt =
1262 idxstmt,
1263 InvalidOid,
1265 constraintOid,
1270 }
1274 /*
1275 * If there are any row-level triggers, clone them to the new
1276 * partition.
1277 */
1281 /*
1282 * And foreign keys too. Note that because we're freshly creating the
1283 * table, there is no need to verify these new constraints.
1284 */
1288 }
1290 /*
1291 * Now add any newly specified CHECK constraints to the new relation. Same
1292 * as for defaults above, but these need to come after partitioning is set
1293 * up.
1294 */
1299 /*
1300 * Finally, merge the not-null constraints that are declared directly with
1301 * those that come from parent relations (making sure to count inheritance
1302 * appropriately for each), create them, and set the attnotnull flag on
1303 * columns that don't yet have it.
1304 */
1306 old_notnulls);
1312 /*
1313 * Clean up. We keep lock on new relation (although it shouldn't be
1314 * visible to anyone else anyway, until commit).
1315 */
1319 }
1321 /*
1322 * BuildDescForRelation
1323 *
1324 * Given a list of ColumnDef nodes, build a TupleDesc.
1325 *
1326 * Note: This is only for the limited purpose of table and view creation. Not
1327 * everything is filled in. A real tuple descriptor should be obtained from
1328 * the relcache.
1329 */
1330 TupleDesc
1332 {
1334 AttrNumber attnum;
1336 TupleDesc desc;
1338 Oid atttypid;
1339 int32 atttypmod;
1340 Oid attcollation;
1343 /*
1344 * allocate a new tuple descriptor
1345 */
1352 {
1354 AclResult aclresult;
1355 Form_pg_attribute att;
1357 /*
1358 * for each entry in the list, get the name and type information from
1359 * the list and have TupleDescInitEntry fill in the attribute
1360 * information we need.
1361 */
1362 attnum++;
1382 attname)));
1388 /* Override TupleDescInitEntry's settings as requested */
1391 /* Fill in additional stuff not handled by TupleDescInitEntry */
1404 }
1407 }
1409 /*
1410 * Emit the right error or warning message for a "DROP" command issued on a
1411 * non-existent relation
1412 */
1413 static void
1415 {
1420 {
1422 {
1426 }
1427 else
1428 {
1432 }
1434 }
1437 {
1439 {
1441 {
1445 }
1446 else
1447 {
1450 }
1451 }
1452 }
1455 }
1457 /*
1458 * Emit the right error message for a "DROP" command issued on a
1459 * relation of the wrong type
1460 */
1461 static void
1463 {
1475 /* wrongkind could be something we don't have in our table... */
1481 }
1483 /*
1484 * RemoveRelations
1485 * Implements DROP TABLE, DROP INDEX, DROP SEQUENCE, DROP VIEW,
1486 * DROP MATERIALIZED VIEW, DROP FOREIGN TABLE
1487 */
1488 void
1490 {
1497 /* DROP CONCURRENTLY uses a weaker lock, and has some restrictions */
1499 {
1500 /*
1501 * Note that for temporary relations this lock may get upgraded later
1502 * on, but as no other session can access a temporary relation, this
1503 * is actually fine.
1504 */
1515 }
1517 /*
1518 * First we identify all the relations, then we delete them in a single
1519 * performMultipleDeletions() call. This is to avoid unwanted DROP
1520 * RESTRICT errors if one of the relations depends on another.
1521 */
1523 /* Determine required relkind */
1525 {
1555 }
1557 /* Lock and validate each relation; build a list of object addresses */
1561 {
1563 Oid relOid;
1564 ObjectAddress obj;
1567 /*
1568 * These next few steps are a great deal like relation_openrv, but we
1569 * don't bother building a relcache entry since we don't need it.
1570 *
1571 * Check for shared-cache-inval messages before trying to access the
1572 * relation. This is needed to cover the case where the name
1573 * identifies a rel that has been dropped and recreated since the
1574 * start of our transaction: if we don't flush the old syscache entry,
1575 * then we'll latch onto that entry and suffer an error later.
1576 */
1579 /* Look up the appropriate relation using namespace search. */
1583 /* We must initialize these fields to show that no locks are held: */
1588 RangeVarCallbackForDropRelation,
1591 /* Not there? */
1593 {
1596 }
1598 /*
1599 * Decide if concurrent mode needs to be used here or not. The
1600 * callback retrieved the rel's persistence for us.
1601 */
1604 {
1608 }
1610 /*
1611 * Concurrent index drop cannot be used with partitioned indexes,
1612 * either.
1613 */
1621 /*
1622 * If we're told to drop a partitioned index, we must acquire lock on
1623 * all the children of its parent partitioned table before proceeding.
1624 * Otherwise we'd try to lock the child index partitions before their
1625 * tables, leading to potential deadlock against other sessions that
1626 * will lock those objects in the other order.
1627 */
1631 NULL);
1633 /* OK, we're ready to delete this one */
1639 }
1644 }
1646 /*
1647 * Before acquiring a table lock, check whether we have sufficient rights.
1648 * In the case of DROP INDEX, also try to lock the table before the index.
1649 * Also, if the table to be dropped is a partition, we try to lock the parent
1650 * first.
1651 */
1652 static void
1655 {
1656 HeapTuple tuple;
1660 Form_pg_class classform;
1661 LOCKMODE heap_lockmode;
1667 /*
1668 * If we previously locked some other index's heap, and the name we're
1669 * looking up no longer refers to that relation, release the now-useless
1670 * lock.
1671 */
1673 {
1676 }
1678 /*
1679 * Similarly, if we previously locked some other partition's heap, and the
1680 * name we're looking up no longer refers to that relation, release the
1681 * now-useless lock.
1682 */
1684 {
1687 }
1689 /* Didn't find a relation, so no need for locking or permission checks. */
1699 /* Pass back some data to save lookups in RemoveRelations */
1703 /*
1704 * Both RELKIND_RELATION and RELKIND_PARTITIONED_TABLE are OBJECT_TABLE,
1705 * but RemoveRelations() can only pass one relkind for a given relation.
1706 * It chooses RELKIND_RELATION for both regular and partitioned tables.
1707 * That means we must be careful before giving the wrong type error when
1708 * the relation is RELKIND_PARTITIONED_TABLE. An equivalent problem
1709 * exists with indexes.
1710 */
1715 else
1722 /* Allow DROP to either table owner or schema owner */
1729 /*
1730 * Check the case of a system index that might have been invalidated by a
1731 * failed concurrent process and allow its drop. For the time being, this
1732 * only concerns indexes of toast relations that became invalid during a
1733 * REINDEX CONCURRENTLY process.
1734 */
1736 {
1737 HeapTuple locTuple;
1738 Form_pg_index indexform;
1743 {
1746 }
1752 /* Mark object as being an invalid index of system catalogs */
1755 }
1757 /* In the case of an invalid index, it is fine to bypass this check */
1766 /*
1767 * In DROP INDEX, attempt to acquire lock on the parent table before
1768 * locking the index. index_drop() will need this anyway, and since
1769 * regular queries lock tables before their indexes, we risk deadlock if
1770 * we do it the other way around. No error if we don't find a pg_index
1771 * entry, though --- the relation may have been dropped. Note that this
1772 * code will execute for either plain or partitioned indexes.
1773 */
1776 {
1780 }
1782 /*
1783 * Similarly, if the relation is a partition, we must acquire lock on its
1784 * parent before locking the partition. That's because queries lock the
1785 * parent before its partitions, so we risk deadlock if we do it the other
1786 * way around.
1787 */
1789 {
1793 }
1794 }
1796 /*
1797 * ExecuteTruncate
1798 * Executes a TRUNCATE command.
1799 *
1800 * This is a multi-relation truncate. We first open and grab exclusive
1801 * lock on all relations involved, checking permissions and otherwise
1802 * verifying that the relation is OK for truncation. Note that if relations
1803 * are foreign tables, at this stage, we have not yet checked that their
1804 * foreign data in external data sources are OK for truncation. These are
1805 * checked when foreign data are actually truncated later. In CASCADE mode,
1806 * relations having FK references to the targeted relations are automatically
1807 * added to the group; in RESTRICT mode, we check that all FK references are
1808 * internal to the group that's being truncated. Finally all the relations
1809 * are truncated and reindexed.
1810 */
1811 void
1813 {
1819 /*
1820 * Open, exclusive-lock, and check all the explicitly-specified relations
1821 */
1823 {
1825 Relation rel;
1827 Oid myrelid;
1832 NULL);
1834 /* don't throw error for "TRUNCATE foo, foo" */
1838 /* open the relation, we already hold a lock on it */
1841 /*
1842 * RangeVarGetRelidExtended() has done most checks with its callback,
1843 * but other checks with the now-opened Relation remain.
1844 */
1850 /* Log this relation only if needed for logical decoding */
1855 {
1862 {
1868 /* find_all_inheritors already got lock */
1871 /*
1872 * It is possible that the parent table has children that are
1873 * temp tables of other backends. We cannot safely access
1874 * such tables (because of buffering issues), and the best
1875 * thing to do is to silently ignore them. Note that this
1876 * check is the same as one of the checks done in
1877 * truncate_check_activity() called below, still it is kept
1878 * here for simplicity.
1879 */
1881 {
1884 }
1886 /*
1887 * Inherited TRUNCATE commands perform access permission
1888 * checks on the parent table only. So we skip checking the
1889 * children's permissions and don't call
1890 * truncate_check_perms() here.
1891 */
1898 /* Log this relation only if needed for logical decoding */
1901 }
1902 }
1907 errhint("Do not specify the ONLY keyword, or use TRUNCATE ONLY on the partitions directly.")));
1908 }
1913 /* And close the rels */
1915 {
1919 }
1920 }
1922 /*
1923 * ExecuteTruncateGuts
1924 *
1925 * Internal implementation of TRUNCATE. This is called by the actual TRUNCATE
1926 * command (see above) as well as replication subscribers that execute a
1927 * replicated TRUNCATE action.
1928 *
1929 * explicit_rels is the list of Relations to truncate that the command
1930 * specified. relids is the list of Oids corresponding to explicit_rels.
1931 * relids_logged is the list of Oids (a subset of relids) that require
1932 * WAL-logging. This is all a bit redundant, but the existing callers have
1933 * this information handy in this form.
1934 */
1935 void
1941 {
1948 SubTransactionId mySubid;
1952 /*
1953 * Check the explicitly-specified relations.
1954 *
1955 * In CASCADE mode, suck in all referencing relations as well. This
1956 * requires multiple iterations to find indirectly-dependent relations. At
1957 * each phase, we need to exclusive-lock new rels before looking for their
1958 * dependencies, else we might miss something. Also, we check each rel as
1959 * soon as we open it, to avoid a faux pas such as holding lock for a long
1960 * time on a rel we have no permissions for.
1961 */
1964 {
1966 {
1974 {
1976 Relation rel;
1988 /* Log this relation only if needed for logical decoding */
1991 }
1992 }
1993 }
1995 /*
1996 * Check foreign key references. In CASCADE mode, this should be
1997 * unnecessary since we just pulled in all the references; but as a
1998 * cross-check, do it anyway if in an Assert-enabled build.
1999 */
2000 #ifdef USE_ASSERT_CHECKING
2002 #else
2005 #endif
2007 /*
2008 * If we are asked to restart sequences, find all the sequences, lock them
2009 * (we need AccessExclusiveLock for ResetSequence), and check permissions.
2010 * We want to do this early since it's pointless to do all the truncation
2011 * work only to fail on sequence permissions.
2012 */
2014 {
2016 {
2022 {
2024 Relation seq_rel;
2028 /* This check must match AlterSequence! */
2036 }
2037 }
2038 }
2040 /* Prepare to catch AFTER triggers. */
2043 /*
2044 * To fire triggers, we'll need an EState as well as a ResultRelInfo for
2045 * each relation. We don't need to call ExecOpenIndices, though.
2046 *
2047 * We put the ResultRelInfos in the es_opened_result_relations list, even
2048 * though we don't have a range table and don't populate the
2049 * es_result_relations array. That's a bit bogus, but it's enough to make
2050 * ExecGetTriggerResultRel() find them.
2051 */
2057 {
2061 rel,
2063 NULL,
2067 resultRelInfo++;
2068 }
2070 /*
2071 * Process all BEFORE STATEMENT TRUNCATE triggers before we begin
2072 * truncating (this is because one of them might throw an error). Also, if
2073 * we were to allow them to prevent statement execution, that would need
2074 * to be handled here.
2075 */
2078 {
2079 UserContext ucxt;
2087 resultRelInfo++;
2088 }
2090 /*
2091 * OK, truncate each table.
2092 */
2096 {
2099 /* Skip partitioned tables as there is nothing to do */
2103 /*
2104 * Build the lists of foreign tables belonging to each foreign server
2105 * and pass each list to the foreign data wrapper's callback function,
2106 * so that each server can truncate its all foreign tables in bulk.
2107 * Each list is saved as a single entry in a hash table that uses the
2108 * server OID as lookup key.
2109 */
2111 {
2116 /* First time through, initialize hashtable for foreign tables */
2118 {
2119 HASHCTL hctl;
2130 }
2132 /* Find or create cached entry for the foreign table */
2137 /*
2138 * Save the foreign table in the entry of the server that the
2139 * foreign table belongs to.
2140 */
2143 }
2145 /*
2146 * Normally, we need a transaction-safe truncation here. However, if
2147 * the table was either created in the current (sub)transaction or has
2148 * a new relfilenumber in the current (sub)transaction, then we can
2149 * just truncate it in-place, because a rollback would cause the whole
2150 * table or the current physical file to be thrown away anyway.
2151 */
2154 {
2155 /* Immediate, non-rollbackable truncation is OK */
2157 }
2158 else
2159 {
2160 Oid heap_relid;
2161 Oid toast_relid;
2164 /*
2165 * This effectively deletes all rows in the table, and may be done
2166 * in a serializable transaction. In that case we must record a
2167 * rw-conflict in to this transaction from each transaction
2168 * holding a predicate lock on the table.
2169 */
2172 /*
2173 * Need the full transaction-safe pushups.
2174 *
2175 * Create a new empty storage file for the relation, and assign it
2176 * as the relfilenumber value. The old storage file is scheduled
2177 * for deletion at commit.
2178 */
2183 /*
2184 * The same for the toast table, if any.
2185 */
2188 {
2190 AccessExclusiveLock);
2195 }
2197 /*
2198 * Reconstruct the indexes to match, and we're done.
2199 */
2202 }
2205 }
2207 /* Now go through the hash table, and truncate foreign tables */
2209 {
2211 HASH_SEQ_STATUS seq;
2216 {
2218 {
2221 /* truncate_check_rel() has checked that already */
2225 behavior,
2226 restart_seqs);
2227 }
2228 }
2230 {
2232 }
2234 }
2236 /*
2237 * Restart owned sequences if we were asked to.
2238 */
2240 {
2244 }
2246 /*
2247 * Write a WAL record to allow this set of actions to be logically
2248 * decoded.
2249 *
2250 * Assemble an array of relids so we can write a single WAL record for the
2251 * whole action.
2252 */
2254 {
2255 xl_heap_truncate xlrec;
2258 /* should only get here if wal_level >= logical */
2280 }
2282 /*
2283 * Process all AFTER STATEMENT TRUNCATE triggers.
2284 */
2287 {
2288 UserContext ucxt;
2296 resultRelInfo++;
2297 }
2299 /* Handle queued AFTER triggers */
2302 /* We can clean up the EState now */
2305 /*
2306 * Close any rels opened by CASCADE (can't do this while EState still
2307 * holds refs)
2308 */
2311 {
2315 }
2316 }
2318 /*
2319 * Check that a given relation is safe to truncate. Subroutine for
2320 * ExecuteTruncate() and RangeVarCallbackForTruncate().
2321 */
2322 static void
2324 {
2327 /*
2328 * Only allow truncate on regular tables, foreign tables using foreign
2329 * data wrappers supporting TRUNCATE and partitioned tables (although, the
2330 * latter are only being included here for the following checks; no
2331 * physical truncation will occur in their case.).
2332 */
2334 {
2342 relname)));
2343 }
2350 /*
2351 * Most system catalogs can't be truncated at all, or at least not unless
2352 * allow_system_table_mods=on. As an exception, however, we allow
2353 * pg_largeobject to be truncated as part of pg_upgrade, because we need
2354 * to change its relfilenode to match the old cluster, and allowing a
2355 * TRUNCATE command to be executed is the easiest way of doing that.
2356 */
2362 relname)));
2365 }
2367 /*
2368 * Check that current user has the permission to truncate given relation.
2369 */
2370 static void
2372 {
2374 AclResult aclresult;
2376 /* Permissions checks */
2380 relname);
2381 }
2383 /*
2384 * Set of extra sanity checks to check if a given relation is safe to
2385 * truncate. This is split with truncate_check_rel() as
2386 * RangeVarCallbackForTruncate() cannot open a Relation yet.
2387 */
2388 static void
2390 {
2391 /*
2392 * Don't allow truncate on temp tables of other backends ... their local
2393 * buffer manager is not going to cope.
2394 */
2400 /*
2401 * Also check for active uses of the relation in the current transaction,
2402 * including open scans and pending AFTER trigger events.
2403 */
2405 }
2407 /*
2408 * storage_name
2409 * returns the name corresponding to a typstorage/attstorage enum value
2410 */
2413 {
2415 {
2426 }
2427 }
2429 /*----------
2430 * MergeAttributes
2431 * Returns new schema given initial schema and superclasses.
2432 *
2433 * Input arguments:
2434 * 'columns' is the column/attribute definition for the table. (It's a list
2435 * of ColumnDef's.) It is destructively changed.
2436 * 'supers' is a list of OIDs of parent relations, already locked by caller.
2437 * 'relpersistence' is the persistence type of the table.
2438 * 'is_partition' tells if the table is a partition.
2439 *
2440 * Output arguments:
2441 * 'supconstr' receives a list of CookedConstraint representing
2442 * CHECK constraints belonging to parent relations, updated as
2443 * necessary to be valid for the child.
2444 * 'supnotnulls' receives a list of CookedConstraint representing
2445 * not-null constraints based on those from parent relations.
2446 *
2447 * Return value:
2448 * Completed schema list.
2449 *
2450 * Notes:
2451 * The order in which the attributes are inherited is very important.
2452 * Intuitively, the inherited attributes should come first. If a table
2453 * inherits from multiple parents, the order of those attributes are
2454 * according to the order of the parents specified in CREATE TABLE.
2455 *
2456 * Here's an example:
2457 *
2458 * create table person (name text, age int4, location point);
2459 * create table emp (salary int4, manager text) inherits(person);
2460 * create table student (gpa float8) inherits (person);
2461 * create table stud_emp (percent int4) inherits (emp, student);
2462 *
2463 * The order of the attributes of stud_emp is:
2464 *
2465 * person {1:name, 2:age, 3:location}
2466 * / \
2467 * {6:gpa} student emp {4:salary, 5:manager}
2468 * \ /
2469 * stud_emp {7:percent}
2470 *
2471 * If the same attribute name appears multiple times, then it appears
2472 * in the result table in the proper location for its first appearance.
2473 *
2474 * Constraints (including not-null constraints) for the child table
2475 * are the union of all relevant constraints, from both the child schema
2476 * and parent tables. In addition, in legacy inheritance, each column that
2477 * appears in a primary key in any of the parents also gets a NOT NULL
2478 * constraint (partitioning doesn't need this, because the PK itself gets
2479 * inherited.)
2480 *
2481 * The default value for a child column is defined as:
2482 * (1) If the child schema specifies a default, that value is used.
2483 * (2) If neither the child nor any parent specifies a default, then
2484 * the column will not have a default.
2485 * (3) If conflicting defaults are inherited from different parents
2486 * (and not overridden by the child), an error is raised.
2487 * (4) Otherwise the inherited default is used.
2488 *
2489 * Note that the default-value infrastructure is used for generated
2490 * columns' expressions too, so most of the preceding paragraph applies
2491 * to generation expressions too. We insist that a child column be
2492 * generated if and only if its parent(s) are, but it need not have
2493 * the same generation expression.
2494 *----------
2495 */
2499 {
2509 /*
2510 * Check for and reject tables with too many columns. We perform this
2511 * check relatively early for two reasons: (a) we don't run the risk of
2512 * overflowing an AttrNumber in subsequent code (b) an O(n^2) algorithm is
2513 * okay if we're processing <= 1600 columns, but could take minutes to
2514 * execute if the user attempts to create a table with hundreds of
2515 * thousands of columns.
2516 *
2517 * Note that we also need to check that we do not exceed this figure after
2518 * including columns from inherited relations.
2519 */
2524 MaxHeapAttributeNumber)));
2526 /*
2527 * Check for duplicate names in the explicit list of attributes.
2528 *
2529 * Although we might consider merging such entries in the same way that we
2530 * handle name conflicts for inherited attributes, it seems to make more
2531 * sense to assume such conflicts are errors.
2532 *
2533 * We don't use foreach() here because we have two nested loops over the
2534 * columns list, with possible element deletions in the inner one. If we
2535 * used foreach_delete_current() it could only fix up the state of one of
2536 * the loops, so it seems cleaner to use looping over list indexes for
2537 * both loops. Note that any deletion will happen beyond where the outer
2538 * loop is, so its index never needs adjustment.
2539 */
2541 {
2545 {
2546 /*
2547 * Typed table column option that does not belong to a column from
2548 * the type. This works because the columns from the type come
2549 * first in the list. (We omit this check for partition column
2550 * lists; those are processed separately below.)
2551 */
2556 }
2558 /* restpos scans all entries beyond coldef; incr is in loop body */
2560 {
2564 {
2566 {
2567 /*
2568 * merge the column options into the column from the type
2569 */
2576 }
2577 else
2582 }
2583 else
2584 restpos++;
2585 }
2586 }
2588 /*
2589 * In case of a partition, there are no new column definitions, only dummy
2590 * ColumnDefs created for column constraints. Set them aside for now and
2591 * process them at the end.
2592 */
2594 {
2597 }
2599 /*
2600 * Scan the parents left-to-right, and merge their attributes to form a
2601 * list of inherited columns (inh_columns).
2602 */
2605 {
2607 Relation relation;
2608 TupleDesc tupleDesc;
2618 /* caller already got lock */
2621 /*
2622 * Check for active uses of the parent partitioned table in the
2623 * current transaction, such as being used in some manner by an
2624 * enclosing command.
2625 */
2629 /*
2630 * We do not allow partitioned tables and partitions to participate in
2631 * regular inheritance.
2632 */
2652 /*
2653 * If the parent is permanent, so must be all of its partitions. Note
2654 * that inheritance allows that case.
2655 */
2664 /* Permanent rels cannot inherit from temporary ones */
2674 /* If existing rel is temp, it must belong to this session */
2683 /*
2684 * We should have an UNDER permission flag for this, but for now,
2685 * demand that creator of a child table own the parent.
2686 */
2694 /*
2695 * newattmap->attnums[] will contain the child-table attribute numbers
2696 * for the attributes of this parent table. (They are not the same
2697 * for parents after the first one, nor if we have dropped columns.)
2698 */
2701 /* We can't process inherited defaults until newattmap is complete. */
2704 /*
2705 * Request attnotnull on columns that have a not-null constraint
2706 * that's not marked NO INHERIT.
2707 */
2714 parent_attno++)
2715 {
2723 /*
2724 * Ignore dropped columns in the parent.
2725 */
2729 /*
2730 * Create new column definition
2731 */
2740 /*
2741 * Regular inheritance children are independent enough not to
2742 * inherit identity columns. But partitions are integral part of
2743 * a partitioned table and inherit identity column.
2744 */
2748 /*
2749 * Does it match some previously considered column from another
2750 * parent?
2751 */
2754 {
2755 /*
2756 * Yes, try to merge the two column definitions.
2757 */
2762 /*
2763 * Partitions have only one parent, so conflict should never
2764 * occur.
2765 */
2767 }
2768 else
2769 {
2770 /*
2771 * No, create a new inherited column
2772 */
2779 }
2781 /*
2782 * mark attnotnull if parent has it
2783 */
2787 /*
2788 * Locate default/generation expression if any
2789 */
2791 {
2799 /*
2800 * If it's a GENERATED default, it might contain Vars that
2801 * need to be mapped to the inherited column(s)' new numbers.
2802 * We can't do that till newattmap is ready, so just remember
2803 * all the inherited default expressions for the moment.
2804 */
2807 }
2808 }
2810 /*
2811 * Now process any inherited default expressions, adjusting attnos
2812 * using the completed newattmap map.
2813 */
2815 {
2820 /* Adjust Vars to match new table's column numbering */
2823 newattmap,
2826 /*
2827 * For the moment we have to reject whole-row variables. We could
2828 * convert them, if we knew the new table's rowtype OID, but that
2829 * hasn't been assigned yet. (A variable could only appear in a
2830 * generation expression, so the error message is correct.)
2831 */
2836 errdetail("Generation expression for column \"%s\" contains a whole-row reference to table \"%s\".",
2840 /*
2841 * If we already had a default from some prior parent, check to
2842 * see if they are the same. If so, no problem; if not, mark the
2843 * column as having a bogus default. Below, we will complain if
2844 * the bogus default isn't overridden by the child columns.
2845 */
2850 {
2853 }
2854 }
2856 /*
2857 * Now copy the CHECK constraints of this parent, adjusting attnos
2858 * using the completed newattmap map. Identically named constraints
2859 * are merged if possible, else we throw error.
2860 */
2862 {
2866 {
2871 /* ignore if the constraint is non-inheritable */
2875 /* Adjust Vars to match new table's column numbering */
2878 newattmap,
2881 /*
2882 * For the moment we have to reject whole-row variables. We
2883 * could convert them, if we knew the new table's rowtype OID,
2884 * but that hasn't been assigned yet.
2885 */
2891 name,
2896 }
2897 }
2899 /*
2900 * Also copy the not-null constraints from this parent. The
2901 * attnotnull markings were already installed above.
2902 */
2904 {
2910 }
2914 /*
2915 * Close the parent rel, but keep our lock on it until xact commit.
2916 * That will prevent someone else from deleting or ALTERing the parent
2917 * before the child is committed.
2918 */
2920 }
2922 /*
2923 * If we had no inherited attributes, the result columns are just the
2924 * explicitly declared columns. Otherwise, we need to merge the declared
2925 * columns into the inherited column list. Although, we never have any
2926 * explicitly declared columns if the table is a partition.
2927 */
2929 {
2933 {
2938 /*
2939 * Partitions have only one parent and have no column definitions
2940 * of their own, so conflict should never occur.
2941 */
2944 newcol_attno++;
2946 /*
2947 * Does it match some inherited column?
2948 */
2951 {
2952 /*
2953 * Yes, try to merge the two column definitions.
2954 */
2956 }
2957 else
2958 {
2959 /*
2960 * No, attach new column unchanged to result columns.
2961 */
2963 }
2964 }
2968 /*
2969 * Check that we haven't exceeded the legal # of columns after merging
2970 * in inherited columns.
2971 */
2976 MaxHeapAttributeNumber)));
2977 }
2979 /*
2980 * Now that we have the column definition list for a partition, we can
2981 * check whether the columns referenced in the column constraint specs
2982 * actually exist. Also, merge column defaults.
2983 */
2985 {
2987 {
2993 {
2997 {
3000 /*
3001 * Check for conflicts related to generated columns.
3002 *
3003 * Same rules as above: generated-ness has to match the
3004 * parent, but the contents of the generation expression
3005 * can be different.
3006 */
3008 {
3019 }
3020 else
3021 {
3028 }
3030 /*
3031 * Override the parent's default value for this column
3032 * (coldef->cooked_default) with the partition's local
3033 * definition (restdef->raw_default), if there's one. It
3034 * should be physically impossible to get a cooked default
3035 * in the local definition or a raw default in the
3036 * inherited definition, but make sure they're nulls, for
3037 * future-proofing.
3038 */
3042 {
3045 }
3046 }
3047 }
3049 /* complain for constraints on columns not in parent */
3055 }
3056 }
3058 /*
3059 * If we found any conflicting parent default values, check to make sure
3060 * they were overridden by the child.
3061 */
3063 {
3065 {
3069 {
3076 else
3082 }
3083 }
3084 }
3090 }
3093 /*
3094 * MergeCheckConstraint
3095 * Try to merge an inherited CHECK constraint with previous ones
3096 *
3097 * If we inherit identically-named constraints from multiple parents, we must
3098 * merge them, or throw an error if they don't have identical definitions.
3099 *
3100 * constraints is a list of CookedConstraint structs for previous constraints.
3101 *
3102 * If the new constraint matches an existing one, then the existing
3103 * constraint's inheritance count is updated. If there is a conflict (same
3104 * name but different expression), throw an error. If the constraint neither
3105 * matches nor conflicts with an existing one, a new constraint is appended to
3106 * the list.
3107 */
3110 {
3115 {
3120 /* Non-matching names never conflict */
3125 {
3126 /* OK to merge constraint with existing */
3133 /*
3134 * When enforceability differs, the merged constraint should be
3135 * marked as ENFORCED because one of the parents is ENFORCED.
3136 */
3138 {
3141 }
3144 }
3149 name)));
3150 }
3152 /*
3153 * Constraint couldn't be merged with an existing one and also didn't
3154 * conflict with an existing one, so add it as a new one to the list.
3155 */
3164 }
3166 /*
3167 * MergeChildAttribute
3168 * Merge given child attribute definition into given inherited attribute.
3169 *
3170 * Input arguments:
3171 * 'inh_columns' is the list of inherited ColumnDefs.
3172 * 'exist_attno' is the number of the inherited attribute in inh_columns
3173 * 'newcol_attno' is the attribute number in child table's schema definition
3174 * 'newdef' is the column/attribute definition from the child table.
3175 *
3176 * The ColumnDef in 'inh_columns' list is modified. The child attribute's
3177 * ColumnDef remains unchanged.
3178 *
3179 * Notes:
3180 * - The attribute is merged according to the rules laid out in the prologue
3181 * of MergeAttributes().
3182 * - If matching inherited attribute exists but the child attribute can not be
3183 * merged into it, the function throws respective errors.
3184 * - A partition can not have its own column definitions. Hence this function
3185 * is applicable only to a regular inheritance child.
3186 */
3187 static void
3188 MergeChildAttribute(List *inh_columns, int exist_attno, int newcol_attno, const ColumnDef *newdef)
3189 {
3192 Oid inhtypeid,
3193 newtypeid;
3194 int32 inhtypmod,
3195 newtypmod;
3196 Oid inhcollid,
3197 newcollid;
3202 attributeName)));
3203 else
3210 /*
3211 * Must have the same type and typmod
3212 */
3219 attributeName),
3224 /*
3225 * Must have the same collation
3226 */
3233 attributeName),
3238 /*
3239 * Identity is never inherited by a regular inheritance child. Pick
3240 * child's identity definition if there's one.
3241 */
3244 /*
3245 * Copy storage parameter
3246 */
3253 attributeName),
3258 /*
3259 * Copy compression parameter
3260 */
3264 {
3269 attributeName),
3271 }
3273 /*
3274 * Merge of not-null constraints = OR 'em together
3275 */
3278 /*
3279 * Check for conflicts related to generated columns.
3280 *
3281 * If the parent column is generated, the child column will be made a
3282 * generated column if it isn't already. If it is a generated column,
3283 * we'll take its generation expression in preference to the parent's. We
3284 * must check that the child column doesn't specify a default value or
3285 * identity, which matches the rules for a single column in
3286 * parse_utilcmd.c.
3287 *
3288 * Conversely, if the parent column is not generated, the child column
3289 * can't be either. (We used to allow that, but it results in being able
3290 * to override the generation expression via UPDATEs through the parent.)
3291 */
3293 {
3304 }
3305 else
3306 {
3313 }
3315 /*
3316 * If new def has a default, override previous default
3317 */
3319 {
3322 }
3324 /* Mark the column as locally defined */
3326 }
3328 /*
3329 * MergeInheritedAttribute
3330 * Merge given parent attribute definition into specified attribute
3331 * inherited from the previous parents.
3332 *
3333 * Input arguments:
3334 * 'inh_columns' is the list of previously inherited ColumnDefs.
3335 * 'exist_attno' is the number the existing matching attribute in inh_columns.
3336 * 'newdef' is the new parent column/attribute definition to be merged.
3337 *
3338 * The matching ColumnDef in 'inh_columns' list is modified and returned.
3339 *
3340 * Notes:
3341 * - The attribute is merged according to the rules laid out in the prologue
3342 * of MergeAttributes().
3343 * - If matching inherited attribute exists but the new attribute can not be
3344 * merged into it, the function throws respective errors.
3345 * - A partition inherits from only a single parent. Hence this function is
3346 * applicable only to a regular inheritance.
3347 */
3352 {
3355 Oid prevtypeid,
3356 newtypeid;
3357 int32 prevtypmod,
3358 newtypmod;
3359 Oid prevcollid,
3360 newcollid;
3364 attributeName)));
3367 /*
3368 * Must have the same type and typmod
3369 */
3376 attributeName),
3381 /*
3382 * Must have the same collation
3383 */
3390 attributeName),
3395 /*
3396 * Copy/check storage parameter
3397 */
3404 attributeName),
3409 /*
3410 * Copy/check compression parameter
3411 */
3415 {
3420 attributeName),
3423 }
3425 /*
3426 * Check for GENERATED conflicts
3427 */
3432 attributeName)));
3434 /*
3435 * Default and other constraints are handled by the caller.
3436 */
3445 }
3447 /*
3448 * StoreCatalogInheritance
3449 * Updates the system catalogs with proper inheritance information.
3450 *
3451 * supers is a list of the OIDs of the new relation's direct ancestors.
3452 */
3453 static void
3456 {
3457 Relation relation;
3458 int32 seqNumber;
3461 /*
3462 * sanity checks
3463 */
3469 /*
3470 * Store INHERITS information in pg_inherits using direct ancestors only.
3471 * Also enter dependencies on the direct ancestors, and make sure they are
3472 * marked with relhassubclass = true.
3473 *
3474 * (Once upon a time, both direct and indirect ancestors were found here
3475 * and then entered into pg_ipl. Since that catalog doesn't exist
3476 * anymore, there's no need to look for indirect ancestors.)
3477 */
3482 {
3486 child_is_partition);
3487 seqNumber++;
3488 }
3491 }
3493 /*
3494 * Make catalog entries showing relationId as being an inheritance child
3495 * of parentOid. inhRelation is the already-opened pg_inherits catalog.
3496 */
3497 static void
3501 {
3502 ObjectAddress childobject,
3503 parentobject;
3505 /* store the pg_inherits row */
3508 /*
3509 * Store a dependency too
3510 */
3521 /*
3522 * Post creation hook of this inheritance. Since object_access_hook
3523 * doesn't take multiple object identifiers, we relay oid of parent
3524 * relation using auxiliary_id argument.
3525 */
3530 /*
3531 * Mark the parent as having subclasses.
3532 */
3534 }
3536 /*
3537 * Look for an existing column entry with the given name.
3538 *
3539 * Returns the index (starting with 1) if attribute already exists in columns,
3540 * 0 if it doesn't.
3541 */
3542 static int
3544 {
3549 {
3553 i++;
3554 }
3556 }
3559 /*
3560 * SetRelationHasSubclass
3561 * Set the value of the relation's relhassubclass field in pg_class.
3562 *
3563 * It's always safe to set this field to true, because all SQL commands are
3564 * ready to see true and then find no children. On the other hand, commands
3565 * generally assume zero children if this is false.
3566 *
3567 * Caller must hold any self-exclusive lock until end of transaction. If the
3568 * new value is false, caller must have acquired that lock before reading the
3569 * evidence that justified the false value. That way, it properly waits if
3570 * another backend is simultaneously concluding no need to change the tuple
3571 * (new and old values are true).
3572 *
3573 * NOTE: an important side-effect of this operation is that an SI invalidation
3574 * message is sent out to all backends --- including me --- causing plans
3575 * referencing the relation to be rebuilt with the new list of children.
3576 * This must happen even if we find that no change is needed in the pg_class
3577 * row.
3578 */
3579 void
3581 {
3582 Relation relationRelation;
3583 HeapTuple tuple;
3584 Form_pg_class classtuple;
3591 /*
3592 * Fetch a modifiable copy of the tuple, modify it, update pg_class.
3593 */
3601 {
3604 }
3605 else
3606 {
3607 /* no need to change tuple, but force relcache rebuild anyway */
3609 }
3613 }
3615 /*
3616 * CheckRelationTableSpaceMove
3617 * Check if relation can be moved to new tablespace.
3618 *
3619 * NOTE: The caller must hold AccessExclusiveLock on the relation.
3620 *
3621 * Returns true if the relation can be moved to the new tablespace; raises
3622 * an error if it is not possible to do the move; returns false if the move
3623 * would have no effect.
3624 */
3625 bool
3627 {
3628 Oid oldTableSpaceId;
3630 /*
3631 * No work if no change in tablespace. Note that MyDatabaseTableSpace is
3632 * stored as 0.
3633 */
3639 /*
3640 * We cannot support moving mapped relations into different tablespaces.
3641 * (In particular this eliminates all shared catalogs.)
3642 */
3649 /* Cannot move a non-shared relation into pg_global */
3655 /*
3656 * Do not allow moving temp tables of other backends ... their local
3657 * buffer manager is not going to cope.
3658 */
3665 }
3667 /*
3668 * SetRelationTableSpace
3669 * Set new reltablespace and relfilenumber in pg_class entry.
3670 *
3671 * newTableSpaceId is the new tablespace for the relation, and
3672 * newRelFilenumber its new filenumber. If newRelFilenumber is
3673 * InvalidRelFileNumber, this field is not updated.
3674 *
3675 * NOTE: The caller must hold AccessExclusiveLock on the relation.
3676 *
3677 * The caller of this routine had better check if a relation can be
3678 * moved to this new tablespace by calling CheckRelationTableSpaceMove()
3679 * first, and is responsible for making the change visible with
3680 * CommandCounterIncrement().
3681 */
3682 void
3684 Oid newTableSpaceId,
3685 RelFileNumber newRelFilenumber)
3686 {
3687 Relation pg_class;
3688 HeapTuple tuple;
3689 ItemPointerData otid;
3690 Form_pg_class rd_rel;
3695 /* Get a modifiable copy of the relation's pg_class row. */
3704 /* Update the pg_class row. */
3712 /*
3713 * Record dependency on tablespace. This is only required for relations
3714 * that have no physical storage.
3715 */
3722 }
3724 /*
3725 * renameatt_check - basic sanity checks before attribute rename
3726 */
3727 static void
3729 {
3737 /*
3738 * Renaming the columns of sequences or toast tables doesn't actually
3739 * break anything from the system's point of view, since internal
3740 * references are by attnum. But it doesn't seem right to allow users to
3741 * change names that are hardcoded into the system, hence the following
3742 * restriction.
3743 */
3758 /*
3759 * permissions checking. only the owner of a class can change its schema.
3760 */
3769 }
3771 /*
3772 * renameatt_internal - workhorse for renameatt
3773 *
3774 * Return value is the attribute number in the 'myrelid' relation.
3775 */
3776 static AttrNumber
3783 DropBehavior behavior)
3784 {
3785 Relation targetrelation;
3786 Relation attrelation;
3787 HeapTuple atttup;
3788 Form_pg_attribute attform;
3789 AttrNumber attnum;
3791 /*
3792 * Grab an exclusive lock on the target table, which we will NOT release
3793 * until end of transaction.
3794 */
3798 /*
3799 * if the 'recurse' flag is set then we are supposed to rename this
3800 * attribute in all classes that inherit from 'relname' (as well as in
3801 * 'relname').
3802 *
3803 * any permissions or problems with duplicate attributes will cause the
3804 * whole transaction to abort, which is what we want -- all or nothing.
3805 */
3807 {
3813 /*
3814 * we need the number of parents for each child so that the recursive
3815 * calls to renameatt() can determine whether there are any parents
3816 * outside the inheritance hierarchy being processed.
3817 */
3821 /*
3822 * find_all_inheritors does the recursive search of the inheritance
3823 * hierarchy, so all we have to do is process all of the relids in the
3824 * list that it returns.
3825 */
3827 {
3833 /* note we need not recurse again */
3835 }
3836 }
3837 else
3838 {
3839 /*
3840 * If we are told not to recurse, there had better not be any child
3841 * tables; else the rename would put them out of step.
3842 *
3843 * expected_parents will only be 0 if we are not already recursing.
3844 */
3850 oldattname)));
3851 }
3853 /* rename attributes in typed tables of composite type */
3855 {
3861 behavior);
3865 }
3874 oldattname)));
3882 oldattname)));
3884 /*
3885 * if the attribute is inherited, forbid the renaming. if this is a
3886 * top-level call to renameatt(), then expected_parents will be 0, so the
3887 * effect of this code will be to prohibit the renaming if the attribute
3888 * is inherited at all. if this is a recursive call to renameatt(),
3889 * expected_parents will be the number of parents the current relation has
3890 * within the inheritance hierarchy being processed, so we'll prohibit the
3891 * renaming only if there are additional parents from elsewhere.
3892 */
3897 oldattname)));
3899 /* new name should not already exist */
3902 /* apply the update */
3916 }
3918 /*
3919 * Perform permissions and integrity checks before acquiring a relation lock.
3920 */
3921 static void
3924 {
3925 HeapTuple tuple;
3926 Form_pg_class form;
3934 }
3936 /*
3937 * renameatt - changes the name of an attribute in a relation
3938 *
3939 * The returned ObjectAddress is that of the renamed column.
3940 */
3941 ObjectAddress
3943 {
3944 Oid relid;
3945 AttrNumber attnum;
3946 ObjectAddress address;
3948 /* lock level taken here should match renameatt_internal */
3951 RangeVarCallbackForRenameAttribute,
3952 NULL);
3955 {
3960 }
3962 attnum =
3974 }
3976 /*
3977 * same logic as renameatt_internal
3978 */
3979 static ObjectAddress
3981 Oid mytypid,
3987 {
3989 Oid constraintOid;
3990 HeapTuple tuple;
3991 Form_pg_constraint con;
3992 ObjectAddress address;
3997 {
3999 }
4000 else
4001 {
4004 /*
4005 * don't tell it whether we're recursing; we allow changing typed
4006 * tables here
4007 */
4011 }
4016 constraintOid);
4023 {
4025 {
4035 {
4042 rename_constraint_internal(childrelid, InvalidOid, oldconname, newconname, false, true, numparents);
4043 }
4044 }
4045 else
4046 {
4052 oldconname)));
4053 }
4059 oldconname)));
4060 }
4066 /* rename the index; this renames the constraint as well */
4068 else
4076 {
4077 /*
4078 * Invalidate relcache so as others can see the new constraint name.
4079 */
4083 }
4086 }
4088 ObjectAddress
4090 {
4095 {
4096 Relation rel;
4097 HeapTuple tup;
4107 }
4108 else
4109 {
4110 /* lock level taken here should match rename_constraint_internal */
4113 RangeVarCallbackForRenameAttribute,
4114 NULL);
4116 {
4121 }
4122 }
4124 return
4132 }
4134 /*
4135 * Execute ALTER TABLE/INDEX/SEQUENCE/VIEW/MATERIALIZED VIEW/FOREIGN TABLE
4136 * RENAME
4137 */
4138 ObjectAddress
4140 {
4142 Oid relid;
4143 ObjectAddress address;
4145 /*
4146 * Grab an exclusive lock on the target table, index, sequence, view,
4147 * materialized view, or foreign table, which we will NOT release until
4148 * end of transaction.
4149 *
4150 * Lock level used here should match RenameRelationInternal, to avoid lock
4151 * escalation. However, because ALTER INDEX can be used with any relation
4152 * type, we mustn't believe without verification.
4153 */
4155 {
4156 LOCKMODE lockmode;
4164 RangeVarCallbackForAlterRelation,
4165 stmt);
4168 {
4173 }
4175 /*
4176 * We allow mismatched statement and object types (e.g., ALTER INDEX
4177 * to rename a table), but we might've used the wrong lock level. If
4178 * that happens, retry with the correct lock level. We don't bother
4179 * if we already acquired AccessExclusiveLock with an index, however.
4180 */
4189 }
4191 /* Do the work */
4197 }
4199 /*
4200 * RenameRelationInternal - change the name of a relation
4201 */
4202 void
4204 {
4205 Relation targetrelation;
4207 ItemPointerData otid;
4208 HeapTuple reltup;
4209 Form_pg_class relform;
4210 Oid namespaceId;
4212 /*
4213 * Grab a lock on the target relation, which we will NOT release until end
4214 * of transaction. We need at least a self-exclusive lock so that
4215 * concurrent DDL doesn't overwrite the rename if they start updating
4216 * while still seeing the old version. The lock also guards against
4217 * triggering relcache reloads in concurrent sessions, which might not
4218 * handle this information changing under them. For indexes, we can use a
4219 * reduced lock level because RelationReloadIndexInfo() handles indexes
4220 * specially.
4221 */
4222 targetrelation = relation_open(myrelid, is_index ? ShareUpdateExclusiveLock : AccessExclusiveLock);
4225 /*
4226 * Find relation's pg_class tuple, and make sure newrelname isn't in use.
4227 */
4240 newrelname)));
4242 /*
4243 * RenameRelation is careful not to believe the caller's idea of the
4244 * relation kind being handled. We don't have to worry about this, but
4245 * let's not be totally oblivious to it. We can process an index as
4246 * not-an-index, but not the other way around.
4247 */
4252 /*
4253 * Update pg_class tuple with new relname. (Scribbling on reltup is OK
4254 * because it's a copy...)
4255 */
4267 /*
4268 * Also rename the associated type, if any.
4269 */
4274 /*
4275 * Also rename the associated constraint, if any.
4276 */
4279 {
4284 }
4286 /*
4287 * Close rel, but keep lock!
4288 */
4290 }
4292 /*
4293 * ResetRelRewrite - reset relrewrite
4294 */
4295 void
4297 {
4299 HeapTuple reltup;
4300 Form_pg_class relform;
4302 /*
4303 * Find relation's pg_class tuple.
4304 */
4312 /*
4313 * Update pg_class tuple.
4314 */
4321 }
4323 /*
4324 * Disallow ALTER TABLE (and similar commands) when the current backend has
4325 * any open reference to the target table besides the one just acquired by
4326 * the calling command; this implies there's an open cursor or active plan.
4327 * We need this check because our lock doesn't protect us against stomping
4328 * on our own foot, only other people's feet!
4329 *
4330 * For ALTER TABLE, the only case known to cause serious trouble is ALTER
4331 * COLUMN TYPE, and some changes are obviously pretty benign, so this could
4332 * possibly be relaxed to only error out for certain types of alterations.
4333 * But the use-case for allowing any of these things is not obvious, so we
4334 * won't work hard at it for now.
4335 *
4336 * We also reject these commands if there are any pending AFTER trigger events
4337 * for the rel. This is certainly necessary for the rewriting variants of
4338 * ALTER TABLE, because they don't preserve tuple TIDs and so the pending
4339 * events would try to fetch the wrong tuples. It might be overly cautious
4340 * in other cases, but again it seems better to err on the side of paranoia.
4341 *
4342 * REINDEX calls this with "rel" referencing the index to be rebuilt; here
4343 * we are worried about active indexscans on the index. The trigger-event
4344 * check can be skipped, since we are doing no damage to the parent table.
4345 *
4346 * The statement name (eg, "ALTER TABLE") is passed for use in error messages.
4347 */
4348 void
4350 {
4357 /* translator: first %s is a SQL command, eg ALTER TABLE */
4366 /* translator: first %s is a SQL command, eg ALTER TABLE */
4369 }
4371 /*
4372 * CheckAlterTableIsSafe
4373 * Verify that it's safe to allow ALTER TABLE on this relation.
4374 *
4375 * This consists of CheckTableNotInUse() plus a check that the relation
4376 * isn't another session's temp table. We must split out the temp-table
4377 * check because there are callers of CheckTableNotInUse() that don't want
4378 * that, notably DROP TABLE. (We must allow DROP or we couldn't clean out
4379 * an orphaned temp schema.) Compare truncate_check_activity().
4380 */
4381 static void
4383 {
4384 /*
4385 * Don't allow ALTER on temp tables of other backends. Their local buffer
4386 * manager is not going to cope if we need to change the table's contents.
4387 * Even if we don't, there may be optimizations that assume temp tables
4388 * aren't subject to such interference.
4389 */
4395 /*
4396 * Also check for active uses of the relation in the current transaction,
4397 * including open scans and pending AFTER trigger events.
4398 */
4400 }
4402 /*
4403 * AlterTableLookupRelation
4404 * Look up, and lock, the OID for the relation named by an alter table
4405 * statement.
4406 */
4407 Oid
4409 {
4412 RangeVarCallbackForAlterRelation,
4413 stmt);
4414 }
4416 /*
4417 * AlterTable
4418 * Execute ALTER TABLE, which can be a list of subcommands
4419 *
4420 * ALTER TABLE is performed in three phases:
4421 * 1. Examine subcommands and perform pre-transformation checking.
4422 * 2. Validate and transform subcommands, and update system catalogs.
4423 * 3. Scan table(s) to check new constraints, and optionally recopy
4424 * the data into new table(s).
4425 * Phase 3 is not performed unless one or more of the subcommands requires
4426 * it. The intention of this design is to allow multiple independent
4427 * updates of the table schema to be performed with only one pass over the
4428 * data.
4429 *
4430 * ATPrepCmd performs phase 1. A "work queue" entry is created for
4431 * each table to be affected (there may be multiple affected tables if the
4432 * commands traverse a table inheritance hierarchy). Also we do preliminary
4433 * validation of the subcommands. Because earlier subcommands may change
4434 * the catalog state seen by later commands, there are limits to what can
4435 * be done in this phase. Generally, this phase acquires table locks,
4436 * checks permissions and relkind, and recurses to find child tables.
4437 *
4438 * ATRewriteCatalogs performs phase 2 for each affected table.
4439 * Certain subcommands need to be performed before others to avoid
4440 * unnecessary conflicts; for example, DROP COLUMN should come before
4441 * ADD COLUMN. Therefore phase 1 divides the subcommands into multiple
4442 * lists, one for each logical "pass" of phase 2.
4443 *
4444 * ATRewriteTables performs phase 3 for those tables that need it.
4445 *
4446 * For most subcommand types, phases 2 and 3 do no explicit recursion,
4447 * since phase 1 already does it. However, for certain subcommand types
4448 * it is only possible to determine how to recurse at phase 2 time; for
4449 * those cases, phase 1 sets the cmd->recurse flag.
4450 *
4451 * Thanks to the magic of MVCC, an error anywhere along the way rolls back
4452 * the whole operation; we don't have to do anything special to clean up.
4453 *
4454 * The caller must lock the relation, with an appropriate lock level
4455 * for the subcommands requested, using AlterTableGetLockLevel(stmt->cmds)
4456 * or higher. We pass the lock level down
4457 * so that we can apply it recursively to inherited tables. Note that the
4458 * lock level we want as we recurse might well be higher than required for
4459 * that specific subcommand. So we pass down the overall lock requirement,
4460 * rather than reassess it at lower levels.
4461 *
4462 * The caller also provides a "context" which is to be passed back to
4463 * utility.c when we need to execute a subcommand such as CREATE INDEX.
4464 * Some of the fields therein, such as the relid, are used here as well.
4465 */
4466 void
4469 {
4470 Relation rel;
4472 /* Caller is required to provide an adequate lock. */
4478 }
4480 /*
4481 * AlterTableInternal
4482 *
4483 * ALTER TABLE with target specified by OID
4484 *
4485 * We do not reject if the relation is already open, because it's quite
4486 * likely that one or more layers of caller have it open. That means it
4487 * is unsafe to use this entry point for alterations that could break
4488 * existing query plans. On the assumption it's not used for such, we
4489 * don't have to reject pending AFTER triggers, either.
4490 *
4491 * Also, since we don't have an AlterTableUtilityContext, this cannot be
4492 * used for any subcommand types that require parse transformation or
4493 * could generate subcommands that have to be passed to ProcessUtility.
4494 */
4495 void
4497 {
4498 Relation rel;
4506 }
4508 /*
4509 * AlterTableGetLockLevel
4510 *
4511 * Sets the overall lock level required for the supplied list of subcommands.
4512 * Policy for doing this set according to needs of AlterTable(), see
4513 * comments there for overall explanation.
4514 *
4515 * Function is called before and after parsing, so it must give same
4516 * answer each time it is called. Some subcommands are transformed
4517 * into other subcommand types, so the transform must never be made to a
4518 * lower lock level than previously assigned. All transforms are noted below.
4519 *
4520 * Since this is called before we lock the table we cannot use table metadata
4521 * to influence the type of lock we acquire.
4522 *
4523 * There should be no lockmodes hardcoded into the subcommand functions. All
4524 * lockmode decisions for ALTER TABLE are made here only. The one exception is
4525 * ALTER TABLE RENAME which is treated as a different statement type T_RenameStmt
4526 * and does not travel through this section of code and cannot be combined with
4527 * any of the subcommands given here.
4528 *
4529 * Note that Hot Standby only knows about AccessExclusiveLocks on the primary
4530 * so any changes that might affect SELECTs running on standbys need to use
4531 * AccessExclusiveLocks even if you think a lesser lock would do, unless you
4532 * have a solution for that also.
4533 *
4534 * Also note that pg_dump uses only an AccessShareLock, meaning that anything
4535 * that takes a lock less than AccessExclusiveLock can change object definitions
4536 * while pg_dump is running. Be careful to check that the appropriate data is
4537 * derived by pg_dump using an MVCC snapshot, rather than syscache lookups,
4538 * otherwise we might end up with an inconsistent dump that can't restore.
4539 */
4540 LOCKMODE
4542 {
4543 /*
4544 * This only works if we read catalog tables using MVCC snapshots.
4545 */
4550 {
4555 {
4556 /*
4557 * These subcommands rewrite the heap, so require full locks.
4558 */
4560 * to SELECT */
4567 /*
4568 * These subcommands may require addition of toast tables. If
4569 * we add a toast table to a table currently being scanned, we
4570 * might miss data added to the new toast table by concurrent
4571 * insert transactions.
4572 */
4574 * ATRewriteCatalogs() */
4578 /*
4579 * Removing constraints can affect SELECTs that have been
4580 * optimized assuming the constraint holds true. See also
4581 * CloneFkReferenced.
4582 */
4588 /*
4589 * Subcommands that may be visible to concurrent SELECTs
4590 */
4601 /*
4602 * Changing owner may remove implicit SELECT privileges
4603 */
4608 /*
4609 * Changing foreign table options may affect optimization.
4610 */
4616 /*
4617 * These subcommands affect write operations only.
4618 */
4630 /*
4631 * These subcommands affect write operations only. XXX
4632 * Theoretically, these could be ShareRowExclusiveLock.
4633 */
4658 {
4662 {
4667 /*
4668 * Cases essentially the same as CREATE INDEX. We
4669 * could reduce the lock strength to ShareLock if
4670 * we can work out how to allow concurrent catalog
4671 * updates. XXX Might be set down to
4672 * ShareRowExclusiveLock but requires further
4673 * analysis.
4674 */
4679 /*
4680 * We add triggers to both tables when we add a
4681 * Foreign Key, so the lock level must be at least
4682 * as strong as CREATE TRIGGER.
4683 */
4689 }
4690 }
4693 /*
4694 * These subcommands affect inheritance behaviour. Queries
4695 * started before us will continue to see the old inheritance
4696 * behaviour, while queries started after we commit will see
4697 * new behaviour. No need to prevent reads or writes to the
4698 * subtable while we hook it up though. Changing the TupDesc
4699 * may be a problem, so keep highest lock.
4700 */
4706 /*
4707 * These subcommands affect implicit row type conversion. They
4708 * have affects similar to CREATE/DROP CAST on queries. don't
4709 * provide for invalidating parse trees as a result of such
4710 * changes, so we keep these at AccessExclusiveLock.
4711 */
4717 /*
4718 * Only used by CREATE OR REPLACE VIEW which must conflict
4719 * with an SELECTs currently using the view.
4720 */
4725 /*
4726 * These subcommands affect general strategies for performance
4727 * and maintenance, though don't change the semantic results
4728 * from normal data reads and writes. Delaying an ALTER TABLE
4729 * behind currently active writes only delays the point where
4730 * the new strategy begins to take effect, so there is no
4731 * benefit in waiting. In this case the minimum restriction
4732 * applies: we don't currently allow concurrent catalog
4733 * updates.
4734 */
4752 /*
4753 * Rel options are more complex than first appears. Options
4754 * are set here for tables, views and indexes; for historical
4755 * reasons these can all be used with ALTER TABLE, so we can't
4756 * decide between them using the basic grammar.
4757 */
4759 * getTables() */
4761 * getTables() */
4772 else
4784 }
4786 /*
4787 * Take the greatest lockmode from any subcommand
4788 */
4791 }
4794 }
4796 /*
4797 * ATController provides top level control over the phases.
4798 *
4799 * parsetree is passed in to allow it to be passed to event triggers
4800 * when requested.
4801 */
4802 static void
4806 {
4810 /* Phase 1: preliminary examination of commands, create work queue */
4812 {
4816 }
4818 /* Close the relation, but keep lock until commit */
4821 /* Phase 2: update system catalogs */
4824 /* Phase 3: scan/rewrite tables as needed, and run afterStmts */
4826 }
4828 /*
4829 * ATPrepCmd
4830 *
4831 * Traffic cop for ALTER TABLE Phase 1 operations, including simple
4832 * recursion and permission checks.
4833 *
4834 * Caller must have acquired appropriate lock type on relation already.
4835 * This lock should be held until commit.
4836 */
4837 static void
4841 {
4845 /* Find or create work queue entry for this table */
4848 /*
4849 * Disallow any ALTER TABLE other than ALTER TABLE DETACH FINALIZE on
4850 * partitions that are pending detach.
4851 */
4859 errhint("Use ALTER TABLE ... DETACH PARTITION ... FINALIZE to complete the pending detach operation."));
4861 /*
4862 * Copy the original subcommand for each table, so we can scribble on it.
4863 * This avoids conflicts when different child tables need to make
4864 * different parse transformations (for example, the same column may have
4865 * different column numbers in different children).
4866 */
4869 /*
4870 * Do permissions and relkind checking, recursion to child tables if
4871 * needed, and any additional phase-1 processing needed. (But beware of
4872 * adding any processing that looks at table details that another
4873 * subcommand could change. In some cases we reject multiple subcommands
4874 * that could try to change the same state in contrary ways.)
4875 */
4877 {
4884 /* Recursion occurs during execution phase */
4891 /* Recursion occurs during execution phase */
4896 /*
4897 * We allow defaults on views so that INSERT into a view can have
4898 * default-ish behavior. This works because the rewriter
4899 * substitutes default values into INSERTs before it expands
4900 * rules.
4901 */
4904 ATT_FOREIGN_TABLE);
4906 /* No command-specific prep needed */
4910 /* This is currently used only in CREATE TABLE */
4911 /* (so the permission check really isn't necessary) */
4914 /* This command never recurses */
4920 ATT_FOREIGN_TABLE);
4921 /* Set up recursion for phase 2; no other prep needed */
4929 ATT_FOREIGN_TABLE);
4930 /* Set up recursion for phase 2; no other prep needed */
4933 /* This should run after AddIdentity, so do it in MISC pass */
4939 ATT_FOREIGN_TABLE);
4940 /* Set up recursion for phase 2; no other prep needed */
4948 /* Set up recursion for phase 2; no other prep needed */
4956 /* Set up recursion for phase 2; no other prep needed */
4979 /* No command-specific prep needed */
4987 /* This command never recurses */
4995 /* No command-specific prep needed */
5001 /* This command never recurses */
5002 /* No command-specific prep needed */
5011 /* Recursion occurs during execution phase */
5016 /* This command never recurses */
5017 /* No command-specific prep needed */
5025 {
5026 /* recurses at exec time; lock descendants and set flag */
5029 }
5034 /* This command never recurses */
5035 /* No command-specific prep needed */
5042 /* Other recursion occurs during execution phase */
5043 /* No command-specific prep needed except saving recurse flag */
5052 /* See comments for ATPrepAlterColumnType */
5056 /* Performs own recursion */
5063 /* This command never recurses */
5064 /* No command-specific prep needed */
5068 /* This command never recurses */
5069 /* No command-specific prep needed */
5076 /* These commands never recurse */
5077 /* No command-specific prep needed */
5099 /* check if another access method change was already requested */
5111 /* This command never recurses */
5121 /* This command never recurses */
5122 /* No command-specific prep needed */
5128 /* This command never recurses */
5135 /* This command never recurses */
5136 /* No command-specific prep needed */
5142 /* Recursion occurs during execution phase */
5148 /* Recursion occurs during execution phase */
5149 /* No command-specific prep needed except saving recurse flag */
5158 /* This command never recurses */
5159 /* No command-specific prep needed */
5171 /* Set up recursion for phase 2; no other prep needed */
5188 /* These commands never recurse */
5189 /* No command-specific prep needed */
5194 /* No command-specific prep needed */
5200 /* No command-specific prep needed */
5205 /* No command-specific prep needed */
5210 /* No command-specific prep needed */
5218 }
5221 /* Add the subcommand to the appropriate list for phase 2 */
5223 }
5225 /*
5226 * ATRewriteCatalogs
5227 *
5228 * Traffic cop for ALTER TABLE Phase 2 operations. Subcommands are
5229 * dispatched in a "safe" execution order (designed to avoid unnecessary
5230 * conflicts).
5231 */
5232 static void
5235 {
5238 /*
5239 * We process all the tables "in parallel", one pass at a time. This is
5240 * needed because we may have to propagate work from one table to another
5241 * (specifically, ALTER TYPE on a foreign key's PK has to dispatch the
5242 * re-adding of the foreign key constraint to the other table). Work can
5243 * only be propagated into later passes, however.
5244 */
5246 {
5247 /* Go through each table that needs to be processed */
5249 {
5257 /*
5258 * Open the relation and store it in tab. This allows subroutines
5259 * close and reopen, if necessary. Appropriate lock was obtained
5260 * by phase 1, needn't get it again.
5261 */
5269 /*
5270 * After the ALTER TYPE or SET EXPRESSION pass, do cleanup work
5271 * (this is not done in ATExecAlterColumnType since it should be
5272 * done only once if multiple columns of a table are altered).
5273 */
5278 {
5281 }
5282 }
5283 }
5285 /* Check to see if a toast table must be added. */
5287 {
5290 /*
5291 * If the table is source table of ATTACH PARTITION command, we did
5292 * not modify anything about it that will change its toasting
5293 * requirement, so no need to check.
5294 */
5300 }
5301 }
5303 /*
5304 * ATExecCmd: dispatch a subcommand to appropriate execution routine
5305 */
5306 static void
5310 {
5315 {
5370 lockmode);
5376 NULL);
5380 lockmode);
5384 lockmode);
5391 /* Transform the command only during initial examination */
5396 /* Depending on constraint type, might be no more work to do now */
5398 address =
5404 address =
5409 * constraint */
5410 address =
5413 NULL);
5420 lockmode);
5435 /* parse transformation was done earlier */
5439 address =
5458 /* nothing to do here, oid columns don't exist anymore */
5462 /*
5463 * Only do this for partitioned tables, for which this is just a
5464 * catalog change. Tables with storage are handled by Phase 3.
5465 */
5472 /*
5473 * Only do this for partitioned tables and indexes, for which this
5474 * is just a catalog change. Other relation types which have
5475 * storage are handled by Phase 3.
5476 */
5491 lockmode);
5497 lockmode);
5503 lockmode);
5509 lockmode);
5515 lockmode);
5521 lockmode);
5527 lockmode);
5533 lockmode);
5589 context);
5590 else
5598 /* ATPrepCmd ensures it must be a table */
5611 }
5613 /*
5614 * Report the subcommand to interested event triggers.
5615 */
5619 /*
5620 * Bump the command counter to ensure the next subcommand in the sequence
5621 * can see the changes so far
5622 */
5624 }
5626 /*
5627 * ATParseTransformCmd: perform parse transformation for one subcommand
5628 *
5629 * Returns the transformed subcommand tree, if there is one, else NULL.
5630 *
5631 * The parser may hand back additional AlterTableCmd(s) and/or other
5632 * utility statements, either before or after the original subcommand.
5633 * Other AlterTableCmds are scheduled into the appropriate slot of the
5634 * AlteredTableInfo (they had better be for later passes than the current one).
5635 * Utility statements that are supposed to happen before the AlterTableCmd
5636 * are executed immediately. Those that are supposed to happen afterwards
5637 * are added to the tab->afterStmts list to be done at the very end.
5638 */
5643 {
5650 /* Gin up an AlterTableStmt with just this subcommand and this table */
5660 /* Transform the AlterTableStmt */
5662 atstmt,
5667 /* Execute any statements that should happen before these subcommand(s) */
5669 {
5674 }
5676 /* Examine the transformed subcommands and schedule them appropriately */
5678 {
5680 AlterTablePass pass;
5682 /*
5683 * This switch need only cover the subcommand types that can be added
5684 * by parse_utilcmd.c; otherwise, we'll use the default strategy of
5685 * executing the subcommand immediately, as a substitute for the
5686 * original subcommand. (Note, however, that this does cause
5687 * AT_AddConstraint subcommands to be rescheduled into later passes,
5688 * which is important for index and foreign key constraints.)
5689 *
5690 * We assume we needn't do any phase-1 checks for added subcommands.
5691 */
5693 {
5701 /* Recursion occurs during execution phase */
5705 {
5717 }
5720 /* This command never recurses */
5721 /* No command-specific prep needed */
5727 }
5730 {
5731 /* Cannot schedule into a pass we already finished */
5733 pass);
5734 }
5736 {
5737 /* OK, queue it up for later */
5739 }
5740 else
5741 {
5742 /*
5743 * We should see at most one subcommand for the current pass,
5744 * which is the transformed version of the original subcommand.
5745 */
5747 {
5748 /* Found the transformed version of our subcommand */
5750 }
5751 else
5753 pass);
5754 }
5755 }
5757 /* Queue up any after-statements to happen at the end */
5761 }
5763 /*
5764 * ATRewriteTables: ALTER TABLE phase 3
5765 */
5766 static void
5769 {
5772 /* Go through each table that needs to be checked or rewritten */
5774 {
5777 /* Relations without storage may be ignored here */
5781 /*
5782 * If we change column data types, the operation has to be propagated
5783 * to tables that use this table's rowtype as a column type.
5784 * tab->newvals will also be non-NULL in the case where we're adding a
5785 * column with a default. We choose to forbid that case as well,
5786 * since composite types might eventually support defaults.
5787 *
5788 * (Eventually we'll probably need to check for composite type
5789 * dependencies even when we're just scanning the table without a
5790 * rewrite, but at the moment a composite type does not enforce any
5791 * constraints, so it's not necessary/appropriate to enforce them just
5792 * during ALTER.)
5793 */
5795 {
5796 Relation rel;
5801 }
5803 /*
5804 * We only need to rewrite the table if at least one column needs to
5805 * be recomputed, or we are changing its persistence or access method.
5806 *
5807 * There are two reasons for requiring a rewrite when changing
5808 * persistence: on one hand, we need to ensure that the buffers
5809 * belonging to each of the two relations are marked with or without
5810 * BM_PERMANENT properly. On the other hand, since rewriting creates
5811 * and assigns a new relfilenumber, we automatically create or drop an
5812 * init fork for the relation as appropriate.
5813 */
5815 {
5816 /* Build a temporary relation and copy data */
5817 Relation OldHeap;
5818 Oid OIDNewHeap;
5819 Oid NewAccessMethod;
5820 Oid NewTableSpace;
5825 /*
5826 * We don't support rewriting of system catalogs; there are too
5827 * many corner cases and too little benefit. In particular this
5828 * is certainly not going to work for mapped catalogs.
5829 */
5842 /*
5843 * Don't allow rewrite on temp tables of other backends ... their
5844 * local buffer manager is not going to cope. (This is redundant
5845 * with the check in CheckAlterTableIsSafe, but for safety we'll
5846 * check here too.)
5847 */
5853 /*
5854 * Select destination tablespace (same as original unless user
5855 * requested a change)
5856 */
5859 else
5862 /*
5863 * Select destination access method (same as original unless user
5864 * requested a change)
5865 */
5868 else
5871 /*
5872 * Select persistence of transient table (same as original unless
5873 * user requested a change)
5874 */
5880 /*
5881 * Fire off an Event Trigger now, before actually rewriting the
5882 * table.
5883 *
5884 * We don't support Event Trigger for nested commands anywhere,
5885 * here included, and parsetree is given NULL when coming from
5886 * AlterTableInternal.
5887 *
5888 * And fire it only once.
5889 */
5895 /*
5896 * Create transient table that will receive the modified data.
5897 *
5898 * Ensure it is marked correctly as logged or unlogged. We have
5899 * to do this here so that buffers for the new relfilenumber will
5900 * have the right persistence set, and at the same time ensure
5901 * that the original filenumbers's buffers will get read in with
5902 * the correct setting (i.e. the original one). Otherwise a
5903 * rollback after the rewrite would possibly result with buffers
5904 * for the original filenumbers having the wrong persistence
5905 * setting.
5906 *
5907 * NB: This relies on swap_relation_files() also swapping the
5908 * persistence. That wouldn't work for pg_class, but that can't be
5909 * unlogged anyway.
5910 */
5914 /*
5915 * Copy the heap data into the new table with the desired
5916 * modifications, and test the current data within the table
5917 * against new constraints generated by ALTER TABLE commands.
5918 */
5921 /*
5922 * Swap the physical files of the old and new heaps, then rebuild
5923 * indexes and discard the old heap. We can use RecentXmin for
5924 * the table's new relfrozenxid because we rewrote all the tuples
5925 * in ATRewriteTable, so no older Xid remains in the table. Also,
5926 * we never try to swap toast tables by content, since we have no
5927 * interest in letting this code work on system catalogs.
5928 */
5932 RecentXmin,
5934 persistence);
5937 }
5939 {
5942 }
5943 else
5944 {
5945 /*
5946 * If required, test the current data within the table against new
5947 * constraints generated by ALTER TABLE commands, but don't
5948 * rebuild data.
5949 */
5954 /*
5955 * If we had SET TABLESPACE but no reason to reconstruct tuples,
5956 * just do a block-by-block copy.
5957 */
5960 }
5962 /*
5963 * Also change persistence of owned sequences, so that it matches the
5964 * table persistence.
5965 */
5967 {
5972 {
5976 }
5977 }
5978 }
5980 /*
5981 * Foreign key constraints are checked in a final pass, since (a) it's
5982 * generally best to examine each one separately, and (b) it's at least
5983 * theoretically possible that we have changed both relations of the
5984 * foreign key, and we'd better have finished both rewrites before we try
5985 * to read the tables.
5986 */
5988 {
5993 /* Relations without storage may be ignored here too */
5998 {
6002 {
6004 Relation refrel;
6007 {
6008 /* Long since locked, no need for another */
6010 }
6019 /*
6020 * No need to mark the constraint row as validated, we did
6021 * that when we inserted the row earlier.
6022 */
6025 }
6026 }
6030 }
6032 /* Finally, run any afterStmts that were queued up */
6034 {
6039 {
6044 }
6045 }
6046 }
6048 /*
6049 * ATRewriteTable: scan or rewrite one table
6050 *
6051 * A rewrite is requested by passing a valid OIDNewHeap; in that case, caller
6052 * must already hold AccessExclusiveLock on it.
6053 */
6054 static void
6056 {
6057 Relation oldrel;
6058 Relation newrel;
6059 TupleDesc oldTupDesc;
6060 TupleDesc newTupDesc;
6066 CommandId mycid;
6067 BulkInsertState bistate;
6071 /*
6072 * Open the relation(s). We have surely already locked the existing
6073 * table.
6074 */
6080 {
6084 }
6085 else
6088 /*
6089 * Prepare a BulkInsertState and options for table_tuple_insert. The FSM
6090 * is empty, so don't bother using it.
6091 */
6093 {
6097 }
6098 else
6099 {
6100 /* keep compiler quiet about using these uninitialized */
6104 }
6106 /*
6107 * Generate the constraint and default execution states
6108 */
6112 /* Build the needed expression execution states */
6114 {
6118 {
6124 /* Nothing to do here */
6129 }
6130 }
6132 /* Build expression execution states for partition check quals */
6134 {
6137 }
6140 {
6143 /* expr already planned */
6145 }
6149 {
6150 /*
6151 * If we are rebuilding the tuples OR if we added any new but not
6152 * verified not-null constraints, check all not-null constraints. This
6153 * is a bit of overkill but it minimizes risk of bugs.
6154 */
6156 {
6161 }
6164 }
6167 {
6171 TableScanDesc scan;
6172 MemoryContext oldCxt;
6175 Snapshot snapshot;
6181 else
6187 {
6188 /*
6189 * All predicate locks on the tuples or pages are about to be made
6190 * invalid, because we move tuples around. Promote them to
6191 * relation locks.
6192 */
6194 }
6198 /*
6199 * Create necessary tuple slots. When rewriting, two slots are needed,
6200 * otherwise one suffices. In the case where one slot suffices, we
6201 * need to use the new tuple descriptor, otherwise some constraints
6202 * can't be evaluated. Note that even when the tuple layout is the
6203 * same and no rewrite is required, the tupDescs might not be
6204 * (consider ADD COLUMN without a default).
6205 */
6207 {
6214 /*
6215 * Set all columns in the new slot to NULL initially, to ensure
6216 * columns added as part of the rewrite are initialized to NULL.
6217 * That is necessary as tab->newvals will not contain an
6218 * expression for columns with a NULL default, e.g. when adding a
6219 * column without a default together with a column with a default
6220 * requiring an actual rewrite.
6221 */
6223 }
6224 else
6225 {
6229 }
6231 /*
6232 * Any attributes that are dropped according to the new tuple
6233 * descriptor can be set to NULL. We precompute the list of dropped
6234 * attributes to avoid needing to do so in the per-tuple loop.
6235 */
6237 {
6240 }
6242 /*
6243 * Scan through the rows, generating a new row if needed and then
6244 * checking all the constraints.
6245 */
6249 /*
6250 * Switch to per-tuple memory context and reset it for each tuple
6251 * produced, so we don't leak memory.
6252 */
6256 {
6260 {
6261 /* Extract data from old tuple */
6265 /* copy attributes */
6271 /* Set dropped attributes to null in new tuple */
6275 /*
6276 * Constraints and GENERATED expressions might reference the
6277 * tableoid column, so fill tts_tableOid with the desired
6278 * value. (We must do this each time, because it gets
6279 * overwritten with newrel's OID during storing.)
6280 */
6283 /*
6284 * Process supplied expressions to replace selected columns.
6285 *
6286 * First, evaluate expressions whose inputs come from the old
6287 * tuple.
6288 */
6292 {
6300 econtext,
6302 }
6306 /*
6307 * Now, evaluate any expressions whose inputs come from the
6308 * new tuple. We assume these columns won't reference each
6309 * other, so that there's no ordering dependency.
6310 */
6314 {
6322 econtext,
6324 }
6327 }
6328 else
6329 {
6330 /*
6331 * If there's no rewrite, old and new table are guaranteed to
6332 * have the same AM, so we can just use the old slot to verify
6333 * new constraints etc.
6334 */
6336 }
6338 /* Now check any constraints on the possibly-changed tuple */
6342 {
6346 {
6355 }
6356 }
6359 {
6363 {
6375 /* Nothing to do here */
6380 }
6381 }
6384 {
6388 errmsg("updated partition constraint for default partition \"%s\" would be violated by some row",
6391 else
6397 }
6399 /* Write the tuple out to the new relation */
6407 }
6416 }
6422 {
6428 }
6429 }
6431 /*
6432 * ATGetQueueEntry: find or create an entry in the ALTER TABLE work queue
6433 */
6436 {
6442 {
6446 }
6448 /*
6449 * Not there, so add it. Note that we make a copy of the relation's
6450 * existing descriptor before anything interesting can happen to it.
6451 */
6466 }
6470 {
6472 {
6599 }
6602 }
6604 /*
6605 * ATSimplePermissions
6606 *
6607 * - Ensure that it is a relation (or possibly a view)
6608 * - Ensure this user is the owner
6609 * - Ensure that it is not a system table
6610 */
6611 static void
6613 {
6617 {
6648 }
6650 /* Wrong target type? */
6652 {
6658 /* translator: %s is a group of some SQL keywords */
6662 else
6663 /* internal error? */
6666 }
6668 /* Permissions checks */
6678 }
6680 /*
6681 * ATSimpleRecursion
6682 *
6683 * Simple table recursion sufficient for most ALTER TABLE operations.
6684 * All direct and indirect children are processed in an unspecified order.
6685 * Note that if a child inherits from the original table via multiple
6686 * inheritance paths, it will be visited just once.
6687 */
6688 static void
6692 {
6693 /*
6694 * Propagate to children, if desired and if there are (or might be) any
6695 * children.
6696 */
6698 {
6705 /*
6706 * find_all_inheritors does the recursive search of the inheritance
6707 * hierarchy, so all we have to do is process all of the relids in the
6708 * list that it returns.
6709 */
6711 {
6713 Relation childrel;
6717 /* find_all_inheritors already got lock */
6722 }
6723 }
6724 }
6726 /*
6727 * Obtain list of partitions of the given table, locking them all at the given
6728 * lockmode and ensuring that they all pass CheckAlterTableIsSafe.
6729 *
6730 * This function is a no-op if the given relation is not a partitioned table;
6731 * in particular, nothing is done if it's a legacy inheritance parent.
6732 */
6733 static void
6735 {
6737 {
6742 /* first element is the parent rel; must ignore it */
6744 {
6745 Relation childrel;
6747 /* find_all_inheritors already got lock */
6751 }
6753 }
6754 }
6756 /*
6757 * ATTypedTableRecursion
6758 *
6759 * Propagate ALTER TYPE operations to the typed tables of that type.
6760 * Also check the RESTRICT/CASCADE behavior. Given CASCADE, also permit
6761 * recursion to inheritance children of the typed tables.
6762 */
6763 static void
6766 {
6777 {
6779 Relation childrel;
6785 }
6786 }
6789 /*
6790 * find_composite_type_dependencies
6791 *
6792 * Check to see if the type "typeOid" is being used as a column in some table
6793 * (possibly nested several levels deep in composite types, arrays, etc!).
6794 * Eventually, we'd like to propagate the check or rewrite operation
6795 * into such tables, but for now, just error out if we find any.
6796 *
6797 * Caller should provide either the associated relation of a rowtype,
6798 * or a type name (not both) for use in the error message, if any.
6799 *
6800 * Note that "typeOid" is not necessarily a composite type; it could also be
6801 * another container type such as an array or range, or a domain over one of
6802 * these things. The name of this function is therefore somewhat historical,
6803 * but it's not worth changing.
6804 *
6805 * We assume that functions and views depending on the type are not reasons
6806 * to reject the ALTER. (How safe is this really?)
6807 */
6808 void
6811 {
6812 Relation depRel;
6814 SysScanDesc depScan;
6815 HeapTuple depTup;
6817 /* since this function recurses, it could be driven to stack overflow */
6820 /*
6821 * We scan pg_depend to find those things that depend on the given type.
6822 * (We assume we can ignore refobjsubid for a type.)
6823 */
6827 Anum_pg_depend_refclassid,
6831 Anum_pg_depend_refobjid,
6839 {
6841 Relation rel;
6842 TupleDesc tupleDesc;
6843 Form_pg_attribute att;
6845 /* Check for directly dependent types */
6847 {
6848 /*
6849 * This must be an array, domain, or range containing the given
6850 * type, so recursively check for uses of this type. Note that
6851 * any error message will mention the original type not the
6852 * container; this is intentional.
6853 */
6857 }
6859 /* Else, ignore dependees that aren't relations */
6866 /*
6867 * If objsubid identifies a specific column, refer to that in error
6868 * messages. Otherwise, search to see if there's a user column of the
6869 * type. (We assume system columns are never of interesting types.)
6870 * The search is needed because an index containing an expression
6871 * column of the target type will just be recorded as a whole-relation
6872 * dependency. If we do not find a column of the type, the dependency
6873 * must indicate that the type is transiently referenced in an index
6874 * expression but not stored on disk, which we assume is OK, just as
6875 * we do for references in views. (It could also be that the target
6876 * type is embedded in some container type that is stored in an index
6877 * column, but the previous recursion should catch such cases.)
6878 */
6881 else
6882 {
6885 {
6890 }
6892 {
6893 /* No such column, so assume OK */
6896 }
6897 }
6899 /*
6900 * We definitely should reject if the relation has storage. If it's
6901 * partitioned, then perhaps we don't have to reject: if there are
6902 * partitions then we'll fail when we find one, else there is no
6903 * stored data to worry about. However, it's possible that the type
6904 * change would affect conclusions about whether the type is sortable
6905 * or hashable and thus (if it's a partitioning column) break the
6906 * partitioning rule. For now, reject for partitioned rels too.
6907 */
6910 {
6915 origTypeName,
6932 else
6939 }
6941 {
6942 /*
6943 * A view or composite type itself isn't a problem, but we must
6944 * recursively check for indirect dependencies via its rowtype.
6945 */
6948 }
6951 }
6956 }
6959 /*
6960 * find_typed_table_dependencies
6961 *
6962 * Check to see if a composite type is being used as the type of a
6963 * typed table. Abort if any are found and behavior is RESTRICT.
6964 * Else return the list of tables.
6965 */
6968 {
6969 Relation classRel;
6971 TableScanDesc scan;
6972 HeapTuple tuple;
6978 Anum_pg_class_reloftype,
6985 {
6992 typeName),
6994 else
6996 }
7002 }
7005 /*
7006 * check_of_type
7007 *
7008 * Check whether a type is suitable for CREATE TABLE OF/ALTER TABLE OF. If it
7009 * isn't suitable, throw an error. Currently, we require that the type
7010 * originated with CREATE TYPE AS. We could support any row type, but doing so
7011 * would require handling a number of extra corner cases in the DDL commands.
7012 * (Also, allowing domain-over-composite would open up a can of worms about
7013 * whether and how the domain's constraints should apply to derived tables.)
7014 */
7015 void
7017 {
7022 {
7023 Relation typeRelation;
7029 /*
7030 * Close the parent rel, but keep our AccessShareLock on it until xact
7031 * commit. That will prevent someone else from deleting or ALTERing
7032 * the type before the typed table creation/conversion commits.
7033 */
7042 }
7043 else
7048 }
7051 /*
7052 * ALTER TABLE ADD COLUMN
7053 *
7054 * Adds an additional attribute to a relation making the assumption that
7055 * CHECK, NOT NULL, and FOREIGN KEY constraints will be removed from the
7056 * AT_AddColumn AlterTableCmd by parse_utilcmd.c and added as independent
7057 * AlterTableCmd's.
7058 *
7059 * ADD COLUMN cannot use the normal ALTER TABLE recursion mechanism, because we
7060 * have to decide at runtime whether to recurse or not depending on whether we
7061 * actually add a column or merely merge with an existing column. (We can't
7062 * check this in a static pre-pass because it won't handle multiple inheritance
7063 * situations correctly.)
7064 */
7065 static void
7069 {
7080 }
7082 /*
7083 * Add a column to a table. The return value is the address of the
7084 * new column in the parent relation.
7085 *
7086 * cmd is pass-by-ref so that we can replace it with the parse-transformed
7087 * copy (but that happens only after we check for IF NOT EXISTS).
7088 */
7089 static ObjectAddress
7094 {
7098 Relation pgclass,
7099 attrdesc;
7100 HeapTuple reltup;
7101 Form_pg_class relform;
7102 Form_pg_attribute attribute;
7109 ObjectAddress address;
7110 TupleDesc tupdesc;
7112 /* since this function recurses, it could be driven to stack overflow */
7115 /* At top level, permission check was done in ATPrepCmd, else do it */
7127 /*
7128 * Are we adding the column to a recursion child? If so, check whether to
7129 * merge with an existing definition for the column. If we do merge, we
7130 * must not recurse. Children will already have the column, and recursing
7131 * into them would mess up attinhcount.
7132 */
7134 {
7135 HeapTuple tuple;
7137 /* Does child already have a column by this name? */
7140 {
7142 Oid ctypeId;
7143 int32 ctypmod;
7144 Oid ccollid;
7146 /* Child column must match on type, typmod, and collation */
7164 /* Bump the existing child att's inhcount */
7174 /* Inform the user about the merge */
7181 /* Make the child column change visible */
7185 }
7186 }
7188 /* skip if the name already exists and if_not_exists is true */
7190 {
7193 }
7195 /*
7196 * Okay, we need to add the column, so go ahead and do parse
7197 * transformation. This can result in queueing up, or even immediately
7198 * executing, subsidiary operations (such as creation of unique indexes);
7199 * so we mustn't do it until we have made the if_not_exists check.
7200 *
7201 * When recursing, the command was already transformed and we needn't do
7202 * so again. Also, if context isn't given we can't transform. (That
7203 * currently happens only for AT_AddColumnToView; we expect that view.c
7204 * passed us a ColumnDef that doesn't need work.)
7205 */
7207 {
7212 }
7214 /*
7215 * Regular inheritance children are independent enough not to inherit the
7216 * identity column from parent hence cannot recursively add identity
7217 * column if the table has inheritance children.
7218 *
7219 * Partitions, on the other hand, are integral part of a partitioned table
7220 * and inherit identity column. Hence propagate identity column down the
7221 * partition hierarchy.
7222 */
7224 recurse &&
7239 /* Determine the new attribute's number */
7245 MaxHeapAttributeNumber)));
7247 /*
7248 * Construct new attribute's pg_attribute entry.
7249 */
7254 /* Fix up attribute number */
7257 /* make sure datatype is legal for a column */
7266 /*
7267 * Update pg_class tuple as appropriate
7268 */
7275 /* Post creation hook for new attribute */
7280 /* Make the attribute's catalog entry visible */
7283 /*
7284 * Store the DEFAULT, if any, in the catalogs
7285 */
7287 {
7294 /*
7295 * Attempt to skip a complete table rewrite by storing the specified
7296 * DEFAULT value outside of the heap. This may be disabled inside
7297 * AddRelationNewConstraints if the optimization cannot be applied.
7298 */
7303 /*
7304 * This function is intended for CREATE TABLE, so it processes a
7305 * _list_ of defaults, but we just do one.
7306 */
7310 /* Make the additional catalog changes visible */
7313 /*
7314 * Did the request for a missing value work? If not we'll have to do a
7315 * rewrite
7316 */
7319 }
7321 /*
7322 * Tell Phase 3 to fill in the default expression, if there is one.
7323 *
7324 * If there is no default, Phase 3 doesn't have to do anything, because
7325 * that effectively means that the default is NULL. The heap tuple access
7326 * routines always check for attnum > # of attributes in tuple, and return
7327 * NULL if so, so without any modification of the tuple data we will get
7328 * the effect of NULL values in the new column.
7329 *
7330 * An exception occurs when the new column is of a domain type: the domain
7331 * might have a not-null constraint, or a check constraint that indirectly
7332 * rejects nulls. If there are any domain constraints then we construct
7333 * an explicit NULL default value that will be passed through
7334 * CoerceToDomain processing. (This is a tad inefficient, since it causes
7335 * rewriting the table which we really don't have to do, but the present
7336 * design of domain processing doesn't offer any simple way of checking
7337 * the constraints more directly.)
7338 *
7339 * Note: we use build_column_default, and not just the cooked default
7340 * returned by AddRelationNewConstraints, so that the right thing happens
7341 * when a datatype's default applies.
7342 *
7343 * Note: it might seem that this should happen at the end of Phase 2, so
7344 * that the effects of subsequent subcommands can be taken into account.
7345 * It's intentional that we do it now, though. The new column should be
7346 * filled according to what is said in the ADD COLUMN subcommand, so that
7347 * the effects are the same as if this subcommand had been run by itself
7348 * and the later subcommands had been issued in new ALTER TABLE commands.
7349 *
7350 * We can skip this entirely for relations without storage, since Phase 3
7351 * is certainly not going to touch them. System attributes don't have
7352 * interesting defaults, either.
7353 */
7355 {
7356 /*
7357 * For an identity column, we can't use build_column_default(),
7358 * because the sequence ownership isn't set yet. So do it manually.
7359 */
7361 {
7369 /* must do a rewrite for identity columns */
7371 }
7372 else
7376 {
7377 Oid baseTypeId;
7378 int32 baseTypeMod;
7379 Oid baseTypeColl;
7387 baseTypeId,
7390 COERCION_ASSIGNMENT,
7391 COERCE_IMPLICIT_CAST,
7395 }
7398 {
7407 }
7413 {
7414 /*
7415 * If the new column is NOT NULL, and there is no missing value,
7416 * tell Phase 3 it needs to check for NULLs.
7417 */
7419 }
7420 }
7422 /*
7423 * Add needed dependency entries for the new column.
7424 */
7428 /*
7429 * Propagate to children as appropriate. Unlike most other ALTER
7430 * routines, we have to do this one level of recursion at a time; we can't
7431 * use find_all_inheritors to do it in one pass.
7432 */
7433 children =
7436 /*
7437 * If we are told not to recurse, there had better not be any child
7438 * tables; else the addition would put them out of step.
7439 */
7445 /* Children should see column as singly inherited */
7447 {
7452 }
7453 else
7457 {
7459 Relation childrel;
7462 /* find_inheritance_children already got lock */
7466 /* Find or create work queue entry for this table */
7469 /* Recurse to child; return value is ignored */
7475 }
7479 }
7481 /*
7482 * If a new or renamed column will collide with the name of an existing
7483 * column and if_not_exists is false then error out, else do nothing.
7484 */
7485 static bool
7488 {
7489 HeapTuple attTuple;
7492 /*
7493 * this test is deliberately not attisdropped-aware, since if one tries to
7494 * add a column matching a dropped column name, it's gonna fail anyway.
7495 */
7505 /*
7506 * We throw a different error message for conflicts with system column
7507 * names, since they are normally not shown and the user might otherwise
7508 * be confused about the reason for the conflict.
7509 */
7514 colname)));
7515 else
7516 {
7518 {
7524 }
7530 }
7533 }
7535 /*
7536 * Install a column's dependency on its datatype.
7537 */
7538 static void
7540 {
7541 ObjectAddress myself,
7542 referenced;
7551 }
7553 /*
7554 * Install a column's dependency on its collation.
7555 */
7556 static void
7558 {
7559 ObjectAddress myself,
7560 referenced;
7562 /* We know the default collation is pinned, so don't bother recording it */
7564 {
7572 }
7573 }
7575 /*
7576 * ALTER TABLE ALTER COLUMN DROP NOT NULL
7577 *
7578 * Return the address of the modified column. If the column was already
7579 * nullable, InvalidObjectAddress is returned.
7580 */
7581 static ObjectAddress
7583 LOCKMODE lockmode)
7584 {
7585 HeapTuple tuple;
7586 HeapTuple conTup;
7587 Form_pg_attribute attTup;
7588 AttrNumber attnum;
7589 Relation attr_rel;
7590 ObjectAddress address;
7592 /*
7593 * lookup the attribute
7594 */
7608 /* If the column is already nullable there's nothing to do. */
7610 {
7613 }
7615 /* Prevent them from altering a system attribute */
7620 colName)));
7628 /*
7629 * If rel is partition, shouldn't drop NOT NULL if parent has the same.
7630 */
7632 {
7636 AttrNumber parent_attnum;
7643 colName)));
7645 }
7647 /*
7648 * Find the constraint that makes this column NOT NULL, and drop it.
7649 * dropconstraint_internal() resets attnotnull.
7650 */
7656 /* The normal case: we have a pg_constraint row, remove it */
7667 }
7669 /*
7670 * Helper to set pg_attribute.attnotnull if it isn't set, and to tell phase 3
7671 * to verify it.
7672 *
7673 * When called to alter an existing table, 'wqueue' must be given so that we
7674 * can queue a check that existing tuples pass the constraint. When called
7675 * from table creation, 'wqueue' should be passed as NULL.
7676 */
7677 static void
7679 LOCKMODE lockmode)
7680 {
7681 Form_pg_attribute attr;
7685 /*
7686 * Exit quickly by testing attnotnull from the tupledesc's copy of the
7687 * attribute.
7688 */
7694 {
7695 Relation attr_rel;
7696 HeapTuple tuple;
7710 /*
7711 * If the nullness isn't already proven by validated constraints, have
7712 * ALTER TABLE phase 3 test for it.
7713 */
7715 {
7720 }
7726 }
7727 }
7729 /*
7730 * ALTER TABLE ALTER COLUMN SET NOT NULL
7731 *
7732 * Add a not-null constraint to a single table and its children. Returns
7733 * the address of the constraint added to the parent relation, if one gets
7734 * added, or InvalidObjectAddress otherwise.
7735 *
7736 * We must recurse to child tables during execution, rather than using
7737 * ALTER TABLE's normal prep-time recursion.
7738 */
7739 static ObjectAddress
7742 {
7743 HeapTuple tuple;
7744 AttrNumber attnum;
7745 ObjectAddress address;
7751 /* Guard against stack overflow due to overly deep inheritance tree. */
7754 /* At top level, permission check was done in ATPrepCmd, else do it */
7756 {
7760 }
7769 /* Prevent them from altering a system attribute */
7774 colName)));
7776 /* See if there's already a constraint */
7779 {
7783 /*
7784 * Don't let a NO INHERIT constraint be changed into inherit.
7785 */
7793 /*
7794 * If we find an appropriate constraint, we're almost done, but just
7795 * need to change some properties on it: if we're recursing, increment
7796 * coninhcount; if not, set conislocal if not already set.
7797 */
7799 {
7806 }
7808 {
7811 }
7814 {
7815 Relation constr_rel;
7822 }
7826 else
7828 }
7830 /*
7831 * If we're asked not to recurse, and children exist, raise an error for
7832 * partitioned tables. For inheritance, we act as if NO INHERIT had been
7833 * specified.
7834 */
7838 {
7844 else
7846 }
7848 /*
7849 * No constraint exists; we must add one. First determine a name to use,
7850 * if we haven't already.
7851 */
7853 {
7858 NIL);
7859 }
7865 /* and do it */
7874 /* Mark pg_attribute.attnotnull for the column */
7877 /*
7878 * Recurse to propagate the constraint to children that don't have one.
7879 */
7881 {
7885 lockmode);
7888 {
7896 }
7897 }
7900 }
7902 /*
7903 * NotNullImpliedByRelConstraints
7904 * Does rel's existing constraints imply NOT NULL for the given attribute?
7905 */
7906 static bool
7908 {
7919 /*
7920 * argisrow = false is correct even for a composite column, because
7921 * attnotnull does not represent a SQL-spec IS NOT NULL test in such a
7922 * case, just IS DISTINCT FROM NULL.
7923 */
7928 {
7930 (errmsg_internal("existing constraints on column \"%s.%s\" are sufficient to prove that it does not contain nulls",
7933 }
7936 }
7938 /*
7939 * ALTER TABLE ALTER COLUMN SET/DROP DEFAULT
7940 *
7941 * Return the address of the affected column.
7942 */
7943 static ObjectAddress
7946 {
7948 AttrNumber attnum;
7949 ObjectAddress address;
7951 /*
7952 * get the number of the attribute
7953 */
7961 /* Prevent them from altering a system attribute */
7966 colName)));
7973 /* translator: %s is an SQL ALTER command */
7982 newDefault ?
7983 /* translator: %s is an SQL ALTER command */
7988 /*
7989 * Remove any old default for the column. We use RESTRICT here for
7990 * safety, but at present we do not expect anything to depend on the
7991 * default.
7992 *
7993 * We treat removing the existing default as an internal operation when it
7994 * is preparatory to adding a new default, but as a user-initiated
7995 * operation when the user asked for a drop.
7996 */
8001 {
8002 /* SET DEFAULT */
8011 /*
8012 * This function is intended for CREATE TABLE, so it processes a
8013 * _list_ of defaults, but we just do one.
8014 */
8017 }
8022 }
8024 /*
8025 * Add a pre-cooked default expression.
8026 *
8027 * Return the address of the affected column.
8028 */
8029 static ObjectAddress
8032 {
8033 ObjectAddress address;
8035 /* We assume no checking is required */
8037 /*
8038 * Remove any old default for the column. We use RESTRICT here for
8039 * safety, but at present we do not expect anything to depend on the
8040 * default. (In ordinary cases, there could not be a default in place
8041 * anyway, but it's possible when combining LIKE with inheritance.)
8042 */
8051 }
8053 /*
8054 * ALTER TABLE ALTER COLUMN ADD IDENTITY
8055 *
8056 * Return the address of the affected column.
8057 */
8058 static ObjectAddress
8061 {
8062 Relation attrelation;
8063 HeapTuple tuple;
8064 Form_pg_attribute attTup;
8065 AttrNumber attnum;
8066 ObjectAddress address;
8093 /* Can't alter a system attribute */
8098 colName)));
8100 /*
8101 * Creating a column as identity implies NOT NULL, so adding the identity
8102 * to an existing column that is not NOT NULL would create a state that
8103 * cannot be reproduced without contortions.
8104 */
8108 errmsg("column \"%s\" of relation \"%s\" must be declared NOT NULL before identity can be added",
8135 /*
8136 * Recurse to propagate the identity column to partitions. Identity is
8137 * not inherited in regular inheritance children.
8138 */
8140 {
8147 {
8148 Relation childrel;
8153 }
8154 }
8157 }
8159 /*
8160 * ALTER TABLE ALTER COLUMN SET { GENERATED or sequence options }
8161 *
8162 * Return the address of the affected column.
8163 */
8164 static ObjectAddress
8167 {
8170 HeapTuple tuple;
8171 Form_pg_attribute attTup;
8172 AttrNumber attnum;
8173 Relation attrelation;
8174 ObjectAddress address;
8190 {
8194 {
8200 }
8201 else
8204 }
8206 /*
8207 * Even if there is nothing to change here, we run all the checks. There
8208 * will be a subsequent ALTER SEQUENCE that relies on everything being
8209 * there.
8210 */
8227 colName)));
8236 {
8245 }
8246 else
8252 /*
8253 * Recurse to propagate the identity change to partitions. Identity is not
8254 * inherited in regular inheritance children.
8255 */
8257 {
8264 {
8265 Relation childrel;
8270 }
8271 }
8274 }
8276 /*
8277 * ALTER TABLE ALTER COLUMN DROP IDENTITY
8278 *
8279 * Return the address of the affected column.
8280 */
8281 static ObjectAddress
8284 {
8285 HeapTuple tuple;
8286 Form_pg_attribute attTup;
8287 AttrNumber attnum;
8288 Relation attrelation;
8289 ObjectAddress address;
8290 Oid seqid;
8291 ObjectAddress seqaddress;
8321 colName)));
8324 {
8330 else
8331 {
8338 }
8339 }
8353 /*
8354 * Recurse to drop the identity from column in partitions. Identity is
8355 * not inherited in regular inheritance children so ignore them.
8356 */
8358 {
8365 {
8366 Relation childrel;
8371 }
8372 }
8375 {
8376 /* drop the internal sequence */
8385 }
8388 }
8390 /*
8391 * ALTER TABLE ALTER COLUMN SET EXPRESSION
8392 *
8393 * Return the address of the affected column.
8394 */
8395 static ObjectAddress
8398 {
8399 HeapTuple tuple;
8400 Form_pg_attribute attTup;
8401 AttrNumber attnum;
8402 Oid attrdefoid;
8403 ObjectAddress address;
8422 colName)));
8431 /*
8432 * Clear all the missing values if we're rewriting the table, since this
8433 * renders them pointless.
8434 */
8437 /* make sure we don't conflict with later attribute modifications */
8440 /*
8441 * Find everything that depends on the column (constraints, indexes, etc),
8442 * and record enough information to let us recreate the objects after
8443 * rewrite.
8444 */
8447 /*
8448 * Drop the dependency records of the GENERATED expression, in particular
8449 * its INTERNAL dependency on the column, which would otherwise cause
8450 * dependency.c to refuse to perform the deletion.
8451 */
8458 /* Make above changes visible */
8461 /*
8462 * Get rid of the GENERATED expression itself. We use RESTRICT here for
8463 * safety, but at present we do not expect anything to depend on the
8464 * expression.
8465 */
8469 /* Prepare to store the new expression, in the catalogs */
8476 /* Store the generated expression */
8480 /* Make above new expression visible */
8483 /* Prepare for table rewrite */
8494 /* Drop any pg_statistic entry for the column */
8503 }
8505 /*
8506 * ALTER TABLE ALTER COLUMN DROP EXPRESSION
8507 */
8508 static void
8509 ATPrepDropExpression(Relation rel, AlterTableCmd *cmd, bool recurse, bool recursing, LOCKMODE lockmode)
8510 {
8511 /*
8512 * Reject ONLY if there are child tables. We could implement this, but it
8513 * is a bit complicated. GENERATED clauses must be attached to the column
8514 * definition and cannot be added later like DEFAULT, so if a child table
8515 * has a generation expression that the parent does not have, the child
8516 * column will necessarily be an attislocal column. So to implement ONLY
8517 * here, we'd need extra code to update attislocal of the direct child
8518 * tables, somewhat similar to how DROP COLUMN does it, so that the
8519 * resulting state can be properly dumped and restored.
8520 */
8527 /*
8528 * Cannot drop generation expression from inherited columns.
8529 */
8531 {
8532 HeapTuple tuple;
8533 Form_pg_attribute attTup;
8548 }
8549 }
8551 /*
8552 * Return the address of the affected column.
8553 */
8554 static ObjectAddress
8556 {
8557 HeapTuple tuple;
8558 Form_pg_attribute attTup;
8559 AttrNumber attnum;
8560 Relation attrelation;
8561 Oid attrdefoid;
8562 ObjectAddress address;
8579 colName)));
8582 {
8588 else
8589 {
8596 }
8597 }
8599 /*
8600 * Mark the column as no longer generated. (The atthasdef flag needs to
8601 * get cleared too, but RemoveAttrDefault will handle that.)
8602 */
8608 attnum);
8613 /*
8614 * Drop the dependency records of the GENERATED expression, in particular
8615 * its INTERNAL dependency on the column, which would otherwise cause
8616 * dependency.c to refuse to perform the deletion.
8617 */
8624 /* Make above changes visible */
8627 /*
8628 * Get rid of the GENERATED expression itself. We use RESTRICT here for
8629 * safety, but at present we do not expect anything to depend on the
8630 * default.
8631 */
8638 }
8640 /*
8641 * ALTER TABLE ALTER COLUMN SET STATISTICS
8642 *
8643 * Return value is the address of the modified column
8644 */
8645 static ObjectAddress
8646 ATExecSetStatistics(Relation rel, const char *colName, int16 colNum, Node *newValue, LOCKMODE lockmode)
8647 {
8650 Relation attrelation;
8651 HeapTuple tuple,
8652 newtuple;
8653 Form_pg_attribute attrtuple;
8654 AttrNumber attnum;
8655 ObjectAddress address;
8660 /*
8661 * We allow referencing columns by numbers only for indexes, since table
8662 * column numbers could contain gaps if columns are later dropped.
8663 */
8671 /* -1 was used in previous versions for the default setting */
8673 {
8676 }
8677 else
8681 {
8682 /*
8683 * Limit target to a sane range
8684 */
8686 {
8690 newtarget)));
8691 }
8693 {
8698 newtarget)));
8699 }
8700 }
8705 {
8713 }
8714 else
8715 {
8723 }
8732 colName)));
8736 {
8748 }
8750 /* Build new tuple. */
8755 else
8775 }
8777 /*
8778 * Return value is the address of the modified column
8779 */
8780 static ObjectAddress
8783 {
8784 Relation attrelation;
8785 HeapTuple tuple,
8786 newtuple;
8787 Form_pg_attribute attrtuple;
8788 AttrNumber attnum;
8789 Datum datum,
8790 newOptions;
8792 ObjectAddress address;
8813 colName)));
8815 /* Generate new proposed attoptions (text array) */
8821 /* Validate new options */
8824 /* Build new tuple. */
8829 else
8835 /* Update system catalog. */
8851 }
8853 /*
8854 * Helper function for ATExecSetStorage and ATExecSetCompression
8855 *
8856 * Set the attstorage and/or attcompression fields for index columns
8857 * associated with the specified table column.
8858 */
8859 static void
8861 AttrNumber attnum,
8864 LOCKMODE lockmode)
8865 {
8869 {
8871 Relation indrel;
8873 HeapTuple tuple;
8878 {
8880 {
8883 }
8884 }
8887 {
8890 }
8895 {
8911 }
8914 }
8915 }
8917 /*
8918 * ALTER TABLE ALTER COLUMN SET STORAGE
8919 *
8920 * Return value is the address of the modified column
8921 */
8922 static ObjectAddress
8924 {
8925 Relation attrelation;
8926 HeapTuple tuple;
8927 Form_pg_attribute attrtuple;
8928 AttrNumber attnum;
8929 ObjectAddress address;
8947 colName)));
8957 /*
8958 * Apply the change to indexes as well (only for simple index columns,
8959 * matching behavior of index.c ConstructTupleDescriptor()).
8960 */
8964 lockmode);
8973 }
8976 /*
8977 * ALTER TABLE DROP COLUMN
8978 *
8979 * DROP COLUMN cannot use the normal ALTER TABLE recursion mechanism,
8980 * because we have to decide at runtime whether to recurse or not depending
8981 * on whether attinhcount goes to zero or not. (We can't check this in a
8982 * static pre-pass because it won't handle multiple inheritance situations
8983 * correctly.)
8984 */
8985 static void
8989 {
9000 }
9002 /*
9003 * Drops column 'colName' from relation 'rel' and returns the address of the
9004 * dropped column. The column is also dropped (or marked as no longer
9005 * inherited from relation) from the relation's inheritance children, if any.
9006 *
9007 * In the recursive invocations for inheritance child relations, instead of
9008 * dropping the column directly (if to be dropped at all), its object address
9009 * is added to 'addrs', which must be non-NULL in such invocations. All
9010 * columns are dropped at the same time after all the children have been
9011 * checked recursively.
9012 */
9013 static ObjectAddress
9015 DropBehavior behavior,
9019 {
9020 HeapTuple tuple;
9021 Form_pg_attribute targetatt;
9022 AttrNumber attnum;
9024 ObjectAddress object;
9027 /* At top level, permission check was done in ATPrepCmd, else do it */
9032 /* Initialize addrs on the first invocation */
9035 /* since this function recurses, it could be driven to stack overflow */
9041 /*
9042 * get the number of the attribute
9043 */
9046 {
9048 {
9053 }
9054 else
9055 {
9060 }
9061 }
9066 /* Can't drop a system attribute */
9071 colName)));
9073 /*
9074 * Don't drop inherited columns, unless recursing (presumably from a drop
9075 * of the parent column)
9076 */
9081 colName)));
9083 /*
9084 * Don't drop columns used in the partition key, either. (If we let this
9085 * go through, the key column's dependencies would cause a cascaded drop
9086 * of the whole table, which is surely not what the user expected.)
9087 */
9098 /*
9099 * Propagate to children as appropriate. Unlike most other ALTER
9100 * routines, we have to do this one level of recursion at a time; we can't
9101 * use find_all_inheritors to do it in one pass.
9102 */
9103 children =
9107 {
9108 Relation attr_rel;
9111 /*
9112 * In case of a partitioned table, the column must be dropped from the
9113 * partitions as well.
9114 */
9123 {
9125 Relation childrel;
9126 Form_pg_attribute childatt;
9128 /* find_inheritance_children already got lock */
9143 {
9144 /*
9145 * If the child column has other definition sources, just
9146 * decrement its inheritance count; if not, recurse to delete
9147 * it.
9148 */
9150 {
9151 /* Time to delete this child column, too */
9155 }
9156 else
9157 {
9158 /* Child column must survive my deletion */
9163 /* Make update visible */
9165 }
9166 }
9167 else
9168 {
9169 /*
9170 * If we were told to drop ONLY in this table (no recursion),
9171 * we need to mark the inheritors' attributes as locally
9172 * defined rather than inherited.
9173 */
9179 /* Make update visible */
9181 }
9186 }
9188 }
9190 /* Add object to delete */
9197 {
9198 /* Recursion has ended, drop everything that was collected */
9201 }
9204 }
9206 /*
9207 * Prepare to add a primary key on table, by adding not-null constraints
9208 * on all columns.
9209 */
9210 static void
9214 {
9222 /*
9223 * If not recursing, we must ensure that all children have a NOT NULL
9224 * constraint on the columns, and error out if not.
9225 */
9227 {
9231 lockmode);
9233 {
9235 {
9236 HeapTuple tup;
9237 Form_pg_attribute attrForm;
9250 }
9251 }
9252 }
9254 /* Insert not-null constraints in the queue for the PK columns */
9256 {
9268 }
9269 }
9271 /*
9272 * ALTER TABLE ADD INDEX
9273 *
9274 * There is no such command in the grammar, but parse_utilcmd.c converts
9275 * UNIQUE and PRIMARY KEY constraints into AT_AddIndex subcommands. This lets
9276 * us schedule creation of the index at the appropriate time during ALTER.
9277 *
9278 * Return value is the address of the new index.
9279 */
9280 static ObjectAddress
9283 {
9287 ObjectAddress address;
9292 /* The IndexStmt has already been through transformIndexStmt */
9295 /* suppress schema rights check when rebuilding existing index */
9297 /* skip index build if phase 3 will do it or we're reusing an old one */
9299 /* suppress notices when rebuilding existing index */
9303 stmt,
9309 check_rights,
9311 skip_build,
9312 quiet);
9314 /*
9315 * If TryReuseIndex() stashed a relfilenumber for us, we used it for the
9316 * new index instead of building from scratch. Restore associated fields.
9317 * This may store InvalidSubTransactionId in both fields, in which case
9318 * relcache.c will assume it can rebuild the relcache entry. Hence, do
9319 * this after the CCI that made catalog rows visible to any rebuild. The
9320 * DROP of the old edition of this index will have scheduled the storage
9321 * for deletion at commit, so cancel that pending deletion.
9322 */
9324 {
9331 }
9334 }
9336 /*
9337 * ALTER TABLE ADD STATISTICS
9338 *
9339 * This is no such command in the grammar, but we use this internally to add
9340 * AT_ReAddStatistics subcommands to rebuild extended statistics after a table
9341 * column type change.
9342 */
9343 static ObjectAddress
9346 {
9347 ObjectAddress address;
9351 /* The CreateStatsStmt has already been through transformStatsStmt */
9357 }
9359 /*
9360 * ALTER TABLE ADD CONSTRAINT USING INDEX
9361 *
9362 * Returns the address of the new constraint.
9363 */
9364 static ObjectAddress
9367 {
9369 Relation indexRel;
9374 ObjectAddress address;
9375 bits16 flags;
9381 /*
9382 * Doing this on partitioned tables is not a simple feature to implement,
9383 * so let's punt for now.
9384 */
9396 /* this should have been checked at parse time */
9400 /*
9401 * Determine name to assign to constraint. We require a constraint to
9402 * have the same name as the underlying index; therefore, use the index's
9403 * existing name as the default constraint name, and if the user
9404 * explicitly gives some other name for the constraint, rename the index
9405 * to match.
9406 */
9411 {
9416 }
9418 /* Extra checks needed if making primary key */
9422 /* Note we currently don't support EXCLUSION constraints here */
9425 else
9428 /* Create the catalog entries for the constraint */
9430 INDEX_CONSTR_CREATE_REMOVE_OLD_DEPS |
9436 index_oid,
9437 InvalidOid,
9438 indexInfo,
9439 constraintName,
9440 constraintType,
9441 flags,
9442 allowSystemTableMods,
9448 }
9450 /*
9451 * ALTER TABLE ADD CONSTRAINT
9452 *
9453 * Return value is the address of the new constraint; if no constraint was
9454 * added, InvalidObjectAddress is returned.
9455 */
9456 static ObjectAddress
9459 LOCKMODE lockmode)
9460 {
9465 /*
9466 * Currently, we only expect to see CONSTR_CHECK, CONSTR_NOTNULL and
9467 * CONSTR_FOREIGN nodes arriving here (see the preprocessing done in
9468 * parse_utilcmd.c).
9469 */
9471 {
9474 address =
9477 lockmode);
9482 /*
9483 * Assign or validate constraint name
9484 */
9486 {
9495 }
9496 else
9502 NIL);
9505 newConstraint,
9507 lockmode);
9513 }
9516 }
9518 /*
9519 * Generate the column-name portion of the constraint name for a new foreign
9520 * key given the list of column names that reference the referenced
9521 * table. This will be passed to ChooseConstraintName along with the parent
9522 * table name and the "fkey" suffix.
9523 *
9524 * We know that less than NAMEDATALEN characters will actually be used, so we
9525 * can truncate the result once we've generated that many.
9526 *
9527 * XXX see also ChooseExtendedStatisticNameAddition and
9528 * ChooseIndexNameAddition.
9529 */
9532 {
9539 {
9545 /*
9546 * At this point we have buflen <= NAMEDATALEN. name should be less
9547 * than NAMEDATALEN already, but use strlcpy for paranoia.
9548 */
9553 }
9555 }
9557 /*
9558 * Add a check or not-null constraint to a single table and its children.
9559 * Returns the address of the constraint added to the parent relation,
9560 * if one gets added, or InvalidObjectAddress otherwise.
9561 *
9562 * Subroutine for ATExecAddConstraint.
9563 *
9564 * We must recurse to child tables during execution, rather than using
9565 * ALTER TABLE's normal prep-time recursion. The reason is that all the
9566 * constraints *must* be given the same name, else they won't be seen as
9567 * related later. If the user didn't explicitly specify a name, then
9568 * AddRelationNewConstraints would normally assign different names to the
9569 * child constraints. To fix that, we must capture the name assigned at
9570 * the parent table and pass that down.
9571 */
9572 static ObjectAddress
9576 {
9583 /* Guard against stack overflow due to overly deep inheritance tree. */
9586 /* At top level, permission check was done in ATPrepCmd, else do it */
9591 /*
9592 * Call AddRelationNewConstraints to do the work, making sure it works on
9593 * a copy of the Constraint so transformExpr can't modify the original. It
9594 * returns a list of cooked constraints.
9595 *
9596 * If the constraint ends up getting merged with a pre-existing one, it's
9597 * omitted from the returned list, which is what we want: we do not need
9598 * to do any validation work. That can only happen at child tables,
9599 * though, since we disallow merging at the top level.
9600 */
9607 * here */
9609 /* we don't expect more than one constraint here */
9612 /* Add each to-be-validated constraint to Phase 3's queue */
9614 {
9618 {
9627 }
9629 /* Save the actually assigned name if it was defaulted */
9633 /*
9634 * If adding a not-null constraint, set the pg_attribute flag and tell
9635 * phase 3 to verify existing rows, if needed.
9636 */
9641 }
9643 /* At this point we must have a locked-down name to use */
9646 /* Advance command counter in case same table is visited multiple times */
9649 /*
9650 * If the constraint got merged with an existing constraint, we're done.
9651 * We mustn't recurse to child tables in this case, because they've
9652 * already got the constraint, and visiting them again would lead to an
9653 * incorrect value for coninhcount.
9654 */
9658 /*
9659 * If adding a NO INHERIT constraint, no need to find our children.
9660 */
9664 /*
9665 * Propagate to children as appropriate. Unlike most other ALTER
9666 * routines, we have to do this one level of recursion at a time; we can't
9667 * use find_all_inheritors to do it in one pass.
9668 */
9669 children =
9672 /*
9673 * Check if ONLY was specified with ALTER TABLE. If so, allow the
9674 * constraint creation only if there are no children currently. Error out
9675 * otherwise.
9676 */
9682 /*
9683 * Recurse to create the constraint on each child.
9684 */
9686 {
9688 Relation childrel;
9691 /* find_inheritance_children already got lock */
9695 /* Find or create work queue entry for this table */
9698 /* Recurse to this child */
9703 }
9706 }
9708 /*
9709 * Add a foreign-key constraint to a single table; return the new constraint's
9710 * address.
9711 *
9712 * Subroutine for ATExecAddConstraint. Must already hold exclusive
9713 * lock on the rel, and have done appropriate validity checks for it.
9714 * We do permissions checks here, however.
9715 *
9716 * When the referenced or referencing tables (or both) are partitioned,
9717 * multiple pg_constraint rows are required -- one for each partitioned table
9718 * and each partition on each side (fortunately, not one for every combination
9719 * thereof). We also need action triggers on each leaf partition on the
9720 * referenced side, and check triggers on each leaf partition on the
9721 * referencing side.
9722 */
9723 static ObjectAddress
9727 {
9728 Relation pkrel;
9744 numpks,
9745 numfkdelsetcols;
9746 Oid indexOid;
9748 ObjectAddress address;
9751 /*
9752 * Grab ShareRowExclusiveLock on the pk table, so that someone doesn't
9753 * delete rows out from under us.
9754 */
9757 else
9760 /*
9761 * Validity checks (permission checks wait till we have the column
9762 * numbers)
9763 */
9765 {
9769 errmsg("cannot use ONLY for foreign key on partitioned table \"%s\" referencing relation \"%s\"",
9775 errmsg("cannot add NOT VALID foreign key on partitioned table \"%s\" referencing relation \"%s\"",
9779 }
9794 /*
9795 * References from permanent or unlogged tables to temp tables, and from
9796 * permanent tables to unlogged tables, are disallowed because the
9797 * referenced data can vanish out from under us. References from temp
9798 * tables to any other table type are also disallowed, because other
9799 * backends might need to run the RI triggers on the perm table, but they
9800 * can't reliably see tuples in the local buffers of other backends.
9801 */
9803 {
9827 }
9829 /*
9830 * Look up the referencing attributes to make sure they exist, and record
9831 * their attnums and type and collation OIDs.
9832 */
9849 /*
9850 * If the attribute list for the referenced table was omitted, lookup the
9851 * definition of the primary key and use it. Otherwise, validate the
9852 * supplied attribute list. In either case, discover the index OID and
9853 * index opclasses, and the attnums and type and collation OIDs of the
9854 * attributes.
9855 */
9857 {
9863 /* If the primary key uses WITHOUT OVERLAPS, the fk must use PERIOD */
9868 }
9869 else
9870 {
9875 /* Since we got pk_attrs, one should be a period. */
9881 /* Look for an index matching the column list */
9884 }
9886 /*
9887 * If the referenced primary key has WITHOUT OVERLAPS, the foreign key
9888 * must use PERIOD.
9889 */
9895 /*
9896 * Now we can check permissions.
9897 */
9900 /*
9901 * Check some things for generated columns.
9902 */
9904 {
9908 {
9909 /*
9910 * Check restrictions on UPDATE/DELETE actions, per SQL standard
9911 */
9925 }
9926 }
9928 /*
9929 * Some actions are currently unsupported for foreign keys using PERIOD.
9930 */
9932 {
9948 }
9950 /*
9951 * Look up the equality operators to use in the constraint.
9952 *
9953 * Note that we have to be careful about the difference between the actual
9954 * PK column type and the opclass' declared input type, which might be
9955 * only binary-compatible with it. The declared opcintype is the right
9956 * thing to probe pg_amop with.
9957 */
9963 /*
9964 * On the strength of a previous constraint, we might avoid scanning
9965 * tables to validate this one. See below.
9966 */
9971 {
9974 Oid fktyped;
9977 HeapTuple cla_ht;
9978 Form_pg_opclass cla_tup;
9979 Oid amid;
9980 Oid opfamily;
9981 Oid opcintype;
9982 Oid pfeqop;
9983 Oid ppeqop;
9984 Oid ffeqop;
9985 int16 eqstrategy;
9986 Oid pfeqop_right;
9988 /* We need several fields out of the pg_opclass entry */
9999 {
10000 CompareType cmptype;
10003 /*
10004 * GiST indexes are required to support temporal foreign keys
10005 * because they combine equals and overlaps.
10006 */
10012 /*
10013 * An opclass can use whatever strategy numbers it wants, so we
10014 * ask the opclass what number it actually uses instead of our RT*
10015 * constants.
10016 */
10019 {
10020 HeapTuple tuple;
10028 for_overlaps
10031 errdetail("Could not translate compare type %d for operator class \"%s\" for access method \"%s\".",
10033 }
10034 }
10035 else
10036 {
10037 /*
10038 * Check it's a btree; currently this can never fail since no
10039 * other index AMs support unique indexes. If we ever did have
10040 * other types of unique indexes, we'd need a way to determine
10041 * which operator strategy number is equality. (We could use
10042 * something like GistTranslateStratnum.)
10043 */
10047 }
10049 /*
10050 * There had better be a primary equality operator for the index.
10051 * We'll use it for PK = PK comparisons.
10052 */
10054 eqstrategy);
10060 /*
10061 * Are there equality operators that take exactly the FK type? Assume
10062 * we should look through any domain here.
10063 */
10067 eqstrategy);
10069 {
10072 eqstrategy);
10073 }
10074 else
10075 {
10076 /* keep compiler quiet */
10079 }
10082 {
10083 /*
10084 * Otherwise, look for an implicit cast from the FK type to the
10085 * opcintype, and if found, use the primary equality operator.
10086 * This is a bit tricky because opcintype might be a polymorphic
10087 * type such as ANYARRAY or ANYENUM; so what we have to test is
10088 * whether the two actual column types can be concurrently cast to
10089 * that type. (Otherwise, we'd fail to reject combinations such
10090 * as int[] and point[].)
10091 */
10100 COERCION_IMPLICIT))
10101 {
10104 }
10105 }
10119 /*
10120 * This shouldn't be possible, but better check to make sure we have a
10121 * consistent state for the check below.
10122 */
10123 if ((OidIsValid(pkcoll) && !OidIsValid(fkcoll)) || (!OidIsValid(pkcoll) && OidIsValid(fkcoll)))
10127 {
10134 /*
10135 * SQL requires that both collations are the same. This is
10136 * because we need a consistent notion of equality on both
10137 * columns. We relax this by allowing different collations if
10138 * they are both deterministic. (This is also for backward
10139 * compatibility, because PostgreSQL has always allowed this.)
10140 */
10152 }
10155 {
10156 /*
10157 * When a pfeqop changes, revalidate the constraint. We could
10158 * permit intra-opfamily changes, but that adds subtle complexity
10159 * without any concrete benefit for core types. We need not
10160 * assess ppeqop or ffeqop, which RI_Initial_Check() does not use.
10161 */
10164 old_pfeqop_item);
10165 }
10167 {
10168 Oid old_fktype;
10169 Oid new_fktype;
10170 CoercionPathType old_pathtype;
10171 CoercionPathType new_pathtype;
10172 Oid old_castfunc;
10173 Oid new_castfunc;
10174 Oid old_fkcoll;
10175 Oid new_fkcoll;
10179 /*
10180 * Identify coercion pathways from each of the old and new FK-side
10181 * column types to the right (foreign) operand type of the pfeqop.
10182 * We may assume that pg_constraint.conkey is not changing.
10183 */
10194 /*
10195 * Upon a change to the cast from the FK column to its pfeqop
10196 * operand, revalidate the constraint. For this evaluation, a
10197 * binary coercion cast is equivalent to no cast at all. While
10198 * type implementors should design implicit casts with an eye
10199 * toward consistency of operations like equality, we cannot
10200 * assume here that they have done so.
10201 *
10202 * A function with a polymorphic argument could change behavior
10203 * arbitrarily in response to get_fn_expr_argtype(). Therefore,
10204 * when the cast destination is polymorphic, we only avoid
10205 * revalidation if the input type has not changed at all. Given
10206 * just the core data types and operator classes, this requirement
10207 * prevents no would-be optimizations.
10208 *
10209 * If the cast converts from a base type to a domain thereon, then
10210 * that domain type must be the opcintype of the unique index.
10211 * Necessarily, the primary key column must then be of the domain
10212 * type. Since the constraint was previously valid, all values on
10213 * the foreign side necessarily exist on the primary side and in
10214 * turn conform to the domain. Consequently, we need not treat
10215 * domains specially here.
10216 *
10217 * If the collation changes, revalidation is required, unless both
10218 * collations are deterministic, because those share the same
10219 * notion of equality (because texteq reduces to bitwise
10220 * equality).
10221 *
10222 * We need not directly consider the PK type. It's necessarily
10223 * binary coercible to the opcintype of the unique index column,
10224 * and ri_triggers.c will only deal with PK datums in terms of
10225 * that opcintype. Changing the opcintype also changes pfeqop.
10226 */
10233 }
10238 }
10240 /*
10241 * For FKs with PERIOD we need additional operators to check whether the
10242 * referencing row's range is contained by the aggregated ranges of the
10243 * referenced row(s). For rangetypes and multirangetypes this is
10244 * fk.periodatt <@ range_agg(pk.periodatt). Those are the only types we
10245 * support for now. FKs will look these up at "runtime", but we should
10246 * make sure the lookup works here, even if we don't use the values.
10247 */
10249 {
10250 Oid periodoperoid;
10251 Oid aggedperiodoperoid;
10254 }
10256 /* First, create the constraint catalog entry itself. */
10259 indexOid,
10261 numfks,
10262 pkattnum,
10263 fkattnum,
10264 pfeqoperators,
10265 ppeqoperators,
10266 ffeqoperators,
10267 numfkdelsetcols,
10268 fkdelsetcols,
10270 with_period);
10272 /* Next process the action triggers at the referenced side and recurse */
10274 indexOid,
10276 numfks,
10277 pkattnum,
10278 fkattnum,
10279 pfeqoperators,
10280 ppeqoperators,
10281 ffeqoperators,
10282 numfkdelsetcols,
10283 fkdelsetcols,
10284 old_check_ok,
10286 with_period);
10288 /* Lastly create the check triggers at the referencing side and recurse */
10290 indexOid,
10292 numfks,
10293 pkattnum,
10294 fkattnum,
10295 pfeqoperators,
10296 ppeqoperators,
10297 ffeqoperators,
10298 numfkdelsetcols,
10299 fkdelsetcols,
10300 old_check_ok,
10301 lockmode,
10303 with_period);
10305 /*
10306 * Done. Close pk table, but keep lock until we've committed.
10307 */
10311 }
10313 /*
10314 * validateFkOnDeleteSetColumns
10315 * Verifies that columns used in ON DELETE SET NULL/DEFAULT (...)
10316 * column lists are valid.
10317 */
10318 void
10322 {
10324 {
10329 {
10331 {
10334 }
10335 }
10338 {
10343 errmsg("column \"%s\" referenced in ON DELETE SET action must be part of foreign key", col)));
10344 }
10345 }
10346 }
10348 /*
10349 * addFkConstraint
10350 * Install pg_constraint entries to implement a foreign key constraint.
10351 * Caller must separately invoke addFkRecurseReferenced and
10352 * addFkRecurseReferencing, as appropriate, to install pg_trigger entries
10353 * and (for partitioned tables) recurse to partitions.
10354 *
10355 * fkside: the side of the FK (or both) to create. Caller should
10356 * call addFkRecurseReferenced if this is addFkReferencedSide,
10357 * addFkRecurseReferencing if it's addFkReferencingSide, or both if it's
10358 * addFkBothSides.
10359 * constraintname: the base name for the constraint being added,
10360 * copied to fkconstraint->conname if the latter is not set
10361 * fkconstraint: the constraint being added
10362 * rel: the root referencing relation
10363 * pkrel: the referenced relation; might be a partition, if recursing
10364 * indexOid: the OID of the index (on pkrel) implementing this constraint
10365 * parentConstr: the OID of a parent constraint; InvalidOid if this is a
10366 * top-level constraint
10367 * numfks: the number of columns in the foreign key
10368 * pkattnum: the attnum array of referenced attributes
10369 * fkattnum: the attnum array of referencing attributes
10370 * pf/pp/ffeqoperators: OID array of operators between columns
10371 * numfkdelsetcols: the number of columns in the ON DELETE SET NULL/DEFAULT
10372 * (...) clause
10373 * fkdelsetcols: the attnum array of the columns in the ON DELETE SET
10374 * NULL/DEFAULT clause
10375 * with_period: true if this is a temporal FK
10376 */
10377 static ObjectAddress
10385 {
10386 ObjectAddress address;
10387 Oid constrOid;
10390 int16 coninhcount;
10393 /*
10394 * Verify relkind for each referenced partition. At the top level, this
10395 * is redundant with a previous check, but we need it when recursing.
10396 */
10404 /*
10405 * Caller supplies us with a constraint name; however, it may be used in
10406 * this partition, so come up with a different one in that case.
10407 */
10410 constraintname))
10415 else
10422 {
10426 }
10427 else
10428 {
10432 /*
10433 * always inherit for partitioned tables, never for legacy inheritance
10434 */
10436 }
10438 /*
10439 * Record the FK constraint in pg_constraint.
10440 */
10443 CONSTRAINT_FOREIGN,
10448 parentConstr,
10450 fkattnum,
10451 numfks,
10452 numfks,
10454 indexOid,
10456 pkattnum,
10457 pfeqoperators,
10458 ppeqoperators,
10459 ffeqoperators,
10460 numfks,
10463 fkdelsetcols,
10464 numfkdelsetcols,
10468 NULL,
10477 /*
10478 * In partitioning cases, create the dependency entries for this
10479 * constraint. (For non-partitioned cases, relevant entries were created
10480 * by CreateConstraintEntry.)
10481 *
10482 * On the referenced side, we need the constraint to have an internal
10483 * dependency on its parent constraint; this means that this constraint
10484 * cannot be dropped on its own -- only through the parent constraint. It
10485 * also means the containing partition cannot be dropped on its own, but
10486 * it can be detached, at which point this dependency is removed (after
10487 * verifying that no rows are referenced via this FK.)
10488 *
10489 * When processing the referencing side, we link the constraint via the
10490 * special partitioning dependencies: the parent constraint is the primary
10491 * dependent, and the partition on which the foreign key exists is the
10492 * secondary dependency. That way, this constraint is dropped if either
10493 * of these objects is.
10494 *
10495 * Note that this is only necessary for the subsidiary pg_constraint rows
10496 * in partitions; the topmost row doesn't need any of this.
10497 */
10499 {
10500 ObjectAddress referenced;
10507 else
10508 {
10512 }
10513 }
10515 /* make new constraint visible, in case we add more */
10519 }
10521 /*
10522 * addFkRecurseReferenced
10523 * Recursive helper for the referenced side of foreign key creation,
10524 * which creates the action triggers and recurses
10525 *
10526 * If the referenced relation is a plain relation, create the necessary action
10527 * triggers that implement the constraint. If the referenced relation is a
10528 * partitioned table, then we create a pg_constraint row referencing the parent
10529 * of the referencing side for it and recurse on this routine for each
10530 * partition.
10531 *
10532 * fkconstraint: the constraint being added
10533 * rel: the root referencing relation
10534 * pkrel: the referenced relation; might be a partition, if recursing
10535 * indexOid: the OID of the index (on pkrel) implementing this constraint
10536 * parentConstr: the OID of a parent constraint; InvalidOid if this is a
10537 * top-level constraint
10538 * numfks: the number of columns in the foreign key
10539 * pkattnum: the attnum array of referenced attributes
10540 * fkattnum: the attnum array of referencing attributes
10541 * numfkdelsetcols: the number of columns in the ON DELETE SET
10542 * NULL/DEFAULT (...) clause
10543 * fkdelsetcols: the attnum array of the columns in the ON DELETE SET
10544 * NULL/DEFAULT clause
10545 * pf/pp/ffeqoperators: OID array of operators between columns
10546 * old_check_ok: true if this constraint replaces an existing one that
10547 * was already validated (thus this one doesn't need validation)
10548 * parentDelTrigger and parentUpdTrigger: when recursively called on a
10549 * partition, the OIDs of the parent action triggers for DELETE and
10550 * UPDATE respectively.
10551 * with_period: true if this is a temporal FK
10552 */
10553 static void
10563 {
10564 Oid deleteTriggerOid,
10565 updateTriggerOid;
10570 /*
10571 * Create the action triggers that enforce the constraint.
10572 */
10574 fkconstraint,
10579 /*
10580 * If the referenced table is partitioned, recurse on ourselves to handle
10581 * each partition. We need one pg_constraint row created for each
10582 * partition in addition to the pg_constraint row for the parent table.
10583 */
10585 {
10589 {
10590 Relation partRel;
10593 Oid partIndexId;
10594 ObjectAddress address;
10596 /* XXX would it be better to acquire these locks beforehand? */
10599 /*
10600 * Map the attribute numbers in the referenced side of the FK
10601 * definition to match the partition's column layout.
10602 */
10607 {
10611 }
10612 else
10615 /* Determine the index to use at this level */
10621 /* Create entry at this level ... */
10629 /* ... and recurse to our children */
10635 old_check_ok,
10637 with_period);
10639 /* Done -- clean up (but keep the lock) */
10642 {
10645 }
10646 }
10647 }
10648 }
10650 /*
10651 * addFkRecurseReferencing
10652 * Recursive helper for the referencing side of foreign key creation,
10653 * which creates the check triggers and recurses
10654 *
10655 * If the referencing relation is a plain relation, create the necessary check
10656 * triggers that implement the constraint, and set up for Phase 3 constraint
10657 * verification. If the referencing relation is a partitioned table, then
10658 * we create a pg_constraint row for it and recurse on this routine for each
10659 * partition.
10660 *
10661 * We assume that the referenced relation is locked against concurrent
10662 * deletions. If it's a partitioned relation, every partition must be so
10663 * locked.
10664 *
10665 * wqueue: the ALTER TABLE work queue; NULL when not running as part
10666 * of an ALTER TABLE sequence.
10667 * fkconstraint: the constraint being added
10668 * rel: the referencing relation; might be a partition, if recursing
10669 * pkrel: the root referenced relation
10670 * indexOid: the OID of the index (on pkrel) implementing this constraint
10671 * parentConstr: the OID of the parent constraint (there is always one)
10672 * numfks: the number of columns in the foreign key
10673 * pkattnum: the attnum array of referenced attributes
10674 * fkattnum: the attnum array of referencing attributes
10675 * pf/pp/ffeqoperators: OID array of operators between columns
10676 * numfkdelsetcols: the number of columns in the ON DELETE SET NULL/DEFAULT
10677 * (...) clause
10678 * fkdelsetcols: the attnum array of the columns in the ON DELETE SET
10679 * NULL/DEFAULT clause
10680 * old_check_ok: true if this constraint replaces an existing one that
10681 * was already validated (thus this one doesn't need validation)
10682 * lockmode: the lockmode to acquire on partitions when recursing
10683 * parentInsTrigger and parentUpdTrigger: when being recursively called on
10684 * a partition, the OIDs of the parent check triggers for INSERT and
10685 * UPDATE respectively.
10686 * with_period: true if this is a temporal FK
10687 */
10688 static void
10697 {
10698 Oid insertTriggerOid,
10699 updateTriggerOid;
10710 /*
10711 * Add the check triggers to it and, if necessary, schedule it to be
10712 * checked in Phase 3.
10713 *
10714 * If the relation is partitioned, drill down to do it to its partitions.
10715 */
10718 fkconstraint,
10719 parentConstr,
10720 indexOid,
10725 {
10726 /*
10727 * Tell Phase 3 to check that the constraint is satisfied by existing
10728 * rows. We can skip this during table creation, when requested
10729 * explicitly by specifying NOT VALID in an ADD FOREIGN KEY command,
10730 * and when we're recreating a constraint following a SET DATA TYPE
10731 * operation that did not impugn its validity.
10732 */
10734 {
10750 }
10751 }
10753 {
10755 Relation trigrel;
10757 /*
10758 * Triggers of the foreign keys will be manipulated a bunch of times
10759 * in the loop below. To avoid repeatedly opening/closing the trigger
10760 * catalog relation, we open it here and pass it to the subroutines
10761 * called below.
10762 */
10765 /*
10766 * Recurse to take appropriate action on each partition; either we
10767 * find an existing constraint to reparent to ours, or we create a new
10768 * one.
10769 */
10771 {
10778 ObjectAddress address;
10789 /* Check whether an existing constraint can be repurposed */
10793 {
10798 partitionId,
10799 parentConstr,
10800 numfks,
10801 mapped_fkattnum,
10802 pkattnum,
10803 pfeqoperators,
10804 insertTriggerOid,
10805 updateTriggerOid,
10806 trigrel))
10807 {
10810 }
10811 }
10813 {
10816 }
10818 /*
10819 * No luck finding a good constraint to reuse; create our own.
10820 */
10828 with_period);
10830 /* call ourselves to finalize the creation and we're done */
10832 indexOid,
10834 numfks,
10835 pkattnum,
10836 mapped_fkattnum,
10837 pfeqoperators,
10838 ppeqoperators,
10839 ffeqoperators,
10840 numfkdelsetcols,
10841 fkdelsetcols,
10842 old_check_ok,
10843 lockmode,
10844 insertTriggerOid,
10845 updateTriggerOid,
10846 with_period);
10849 }
10852 }
10853 }
10855 /*
10856 * CloneForeignKeyConstraints
10857 * Clone foreign keys from a partitioned table to a newly acquired
10858 * partition.
10859 *
10860 * partitionRel is a partition of parentRel, so we can be certain that it has
10861 * the same columns with the same datatypes. The columns may be in different
10862 * order, though.
10863 *
10864 * wqueue must be passed to set up phase 3 constraint checking, unless the
10865 * referencing-side partition is known to be empty (such as in CREATE TABLE /
10866 * PARTITION OF).
10867 */
10868 static void
10870 Relation partitionRel)
10871 {
10872 /* This only works for declarative partitioning */
10875 /*
10876 * Clone constraints for which the parent is on the referenced side.
10877 */
10880 /*
10881 * Now clone constraints where the parent is on the referencing side.
10882 */
10884 }
10886 /*
10887 * CloneFkReferenced
10888 * Subroutine for CloneForeignKeyConstraints
10889 *
10890 * Find all the FKs that have the parent relation on the referenced side;
10891 * clone those constraints to the given partition. This is to be called
10892 * when the partition is being created or attached.
10893 *
10894 * This ignores self-referencing FKs; those are handled by CloneFkReferencing.
10895 *
10896 * This recurses to partitions, if the relation being attached is partitioned.
10897 * Recursion is done by calling addFkRecurseReferenced.
10898 */
10899 static void
10901 {
10902 Relation pg_constraint;
10905 SysScanDesc scan;
10907 HeapTuple tuple;
10909 Relation trigrel;
10911 /*
10912 * Search for any constraints where this partition's parent is in the
10913 * referenced side. However, we must not clone any constraint whose
10914 * parent constraint is also going to be cloned, to avoid duplicates. So
10915 * do it in two steps: first construct the list of constraints to clone,
10916 * then go over that list cloning those whose parents are not in the list.
10917 * (We must not rely on the parent being seen first, since the catalog
10918 * scan could return children first.)
10919 */
10927 /* This is a seqscan, as we don't have a usable index ... */
10931 {
10935 }
10939 /*
10940 * Triggers of the foreign keys will be manipulated a bunch of times in
10941 * the loop below. To avoid repeatedly opening/closing the trigger
10942 * catalog relation, we open it here and pass it to the subroutines called
10943 * below.
10944 */
10951 {
10953 Form_pg_constraint constrForm;
10954 Relation fkRel;
10955 Oid indexOid;
10956 Oid partIndexId;
10967 ObjectAddress address;
10968 Oid deleteTriggerOid,
10969 updateTriggerOid;
10976 /*
10977 * As explained above: don't try to clone a constraint for which we're
10978 * going to clone the parent.
10979 */
10981 {
10984 }
10986 /*
10987 * Don't clone self-referencing foreign keys, which can be in the
10988 * partitioned table or in the partition-to-be.
10989 */
10992 {
10995 }
10997 /* We need the same lock level that CreateTrigger will acquire */
11003 conkey,
11004 confkey,
11005 conpfeqop,
11006 conppeqop,
11007 conffeqop,
11009 confdelsetcols);
11021 /* ->fk_attrs determined below */
11032 /* set up colnames that are used to generate the constraint name */
11034 {
11035 Form_pg_attribute att;
11041 }
11043 /*
11044 * Add the new foreign key constraint pointing to the new partition.
11045 * Because this new partition appears in the referenced side of the
11046 * constraint, we don't need to set up for Phase 3 check.
11047 */
11053 /*
11054 * Get the "action" triggers belonging to the constraint to pass as
11055 * parent OIDs for similar triggers that will be created on the
11056 * partition in addFkRecurseReferenced().
11057 */
11062 /* Add this constraint ... */
11070 /* ... and recurse */
11072 fkRel,
11073 partitionRel,
11074 partIndexId,
11076 numfks,
11077 mapped_confkey,
11078 conkey,
11079 conpfeqop,
11080 conppeqop,
11081 conffeqop,
11082 numfkdelsetcols,
11083 confdelsetcols,
11085 deleteTriggerOid,
11086 updateTriggerOid,
11091 }
11094 }
11096 /*
11097 * CloneFkReferencing
11098 * Subroutine for CloneForeignKeyConstraints
11099 *
11100 * For each FK constraint of the parent relation in the given list, find an
11101 * equivalent constraint in its partition relation that can be reparented;
11102 * if one cannot be found, create a new constraint in the partition as its
11103 * child.
11104 *
11105 * If wqueue is given, it is used to set up phase-3 verification for each
11106 * cloned constraint; omit it if such verification is not needed
11107 * (example: the partition is being created anew).
11108 */
11109 static void
11111 {
11116 Relation trigrel;
11118 /* obtain a list of constraints that we need to clone */
11120 {
11123 /*
11124 * Refuse to attach a table as partition that this partitioned table
11125 * already has a foreign key to. This isn't useful schema, which is
11126 * proven by the fact that there have been no user complaints that
11127 * it's already impossible to achieve this in the opposite direction,
11128 * i.e., creating a foreign key that references a partition. This
11129 * restriction allows us to dodge some complexities around
11130 * pg_constraint and pg_trigger row creations that would be needed
11131 * during ATTACH/DETACH for this kind of relationship.
11132 */
11136 errmsg("cannot attach table \"%s\" as a partition because it is referenced by foreign key \"%s\"",
11141 }
11143 /*
11144 * Silently do nothing if there's nothing to do. In particular, this
11145 * avoids throwing a spurious error for foreign tables.
11146 */
11155 /*
11156 * Triggers of the foreign keys will be manipulated a bunch of times in
11157 * the loop below. To avoid repeatedly opening/closing the trigger
11158 * catalog relation, we open it here and pass it to the subroutines called
11159 * below.
11160 */
11163 /*
11164 * The constraint key may differ, if the columns in the partition are
11165 * different. This map is used to convert them.
11166 */
11174 {
11176 Form_pg_constraint constrForm;
11177 Relation pkrel;
11178 HeapTuple tuple;
11190 Oid indexOid;
11191 ObjectAddress address;
11193 Oid insertTriggerOid,
11194 updateTriggerOid;
11200 parentConstrOid);
11203 /* Don't clone constraints whose parents are being cloned */
11205 {
11208 }
11210 /*
11211 * Need to prevent concurrent deletions. If pkrel is a partitioned
11212 * relation, that means to lock all partitions.
11213 */
11225 /*
11226 * Get the "check" triggers belonging to the constraint to pass as
11227 * parent OIDs for similar triggers that will be created on the
11228 * partition in addFkRecurseReferencing(). They are also passed to
11229 * tryAttachPartitionForeignKey() below to simply assign as parents to
11230 * the partition's existing "check" triggers, that is, if the
11231 * corresponding constraints is deemed attachable to the parent
11232 * constraint.
11233 */
11238 /*
11239 * Before creating a new constraint, see whether any existing FKs are
11240 * fit for the purpose. If one is, attach the parent constraint to
11241 * it, and don't clone anything. This way we avoid the expensive
11242 * verification step and don't end up with a duplicate FK, and we
11243 * don't need to recurse to partitions for this constraint.
11244 */
11247 {
11252 parentConstrOid,
11253 numfks,
11254 mapped_conkey,
11255 confkey,
11256 conpfeqop,
11257 insertTriggerOid,
11258 updateTriggerOid,
11259 trigrel))
11260 {
11264 }
11265 }
11267 {
11270 }
11272 /* No dice. Set up to create our own constraint */
11275 /* ->conname determined below */
11280 /* ->fk_attrs determined below */
11291 {
11292 Form_pg_attribute att;
11298 }
11303 /* Create the pg_constraint entry at this level */
11313 /* Done with the cloned constraint's tuple */
11316 /* Create the check triggers, and recurse to partitions, if any */
11318 fkconstraint,
11319 partRel,
11320 pkrel,
11321 indexOid,
11323 numfks,
11324 confkey,
11325 mapped_conkey,
11326 conpfeqop,
11327 conppeqop,
11328 conffeqop,
11329 numfkdelsetcols,
11330 confdelsetcols,
11332 AccessExclusiveLock,
11333 insertTriggerOid,
11334 updateTriggerOid,
11335 with_period);
11337 }
11340 }
11342 /*
11343 * When the parent of a partition receives [the referencing side of] a foreign
11344 * key, we must propagate that foreign key to the partition. However, the
11345 * partition might already have an equivalent foreign key; this routine
11346 * compares the given ForeignKeyCacheInfo (in the partition) to the FK defined
11347 * by the other parameters. If they are equivalent, create the link between
11348 * the two constraints and return true.
11349 *
11350 * If the given FK does not match the one defined by rest of the params,
11351 * return false.
11352 */
11353 static bool
11355 Oid partRelid,
11356 Oid parentConstrOid,
11361 Oid parentInsTrigger,
11362 Oid parentUpdTrigger,
11363 Relation trigrel)
11364 {
11365 HeapTuple parentConstrTup;
11366 Form_pg_constraint parentConstr;
11367 HeapTuple partcontup;
11368 Form_pg_constraint partConstr;
11369 ScanKeyData key;
11370 SysScanDesc scan;
11371 HeapTuple trigtup;
11372 Oid insertTriggerOid,
11373 updateTriggerOid;
11381 /*
11382 * Do some quick & easy initial checks. If any of these fail, we cannot
11383 * use this constraint.
11384 */
11386 {
11389 }
11391 {
11395 {
11398 }
11399 }
11401 /*
11402 * Looks good so far; do some more extensive checks. Presumably the check
11403 * for 'convalidated' could be dropped, since we don't really care about
11404 * that, but let's be careful for now.
11405 */
11418 {
11422 }
11427 /*
11428 * Looks good! Attach this constraint. The action triggers in the new
11429 * partition become redundant -- the parent table already has equivalent
11430 * ones, and those will be able to reach the partition. Remove the ones
11431 * in the partition. We identify them because they have our constraint
11432 * OID, as well as being on the referenced rel.
11433 */
11435 Anum_pg_trigger_tgconstraint,
11441 {
11443 ObjectAddress trigger;
11450 /*
11451 * The constraint is originally set up to contain this trigger as an
11452 * implementation object, so there's a dependency record that links
11453 * the two; however, since the trigger is no longer needed, we remove
11454 * the dependency link in order to be able to drop the trigger while
11455 * keeping the constraint intact.
11456 */
11460 /* make dependency deletion visible to performDeletion */
11465 /* make trigger drop visible, in case the loop iterates */
11467 }
11473 /*
11474 * Like the constraint, attach partition's "check" triggers to the
11475 * corresponding parent triggers.
11476 */
11482 partRelid);
11485 partRelid);
11487 /*
11488 * If the referenced table is partitioned, then the partition we're
11489 * attaching now has extra pg_constraint rows and action triggers that are
11490 * no longer needed. Remove those.
11491 */
11493 {
11496 HeapTuple consttup;
11499 Anum_pg_constraint_conrelid,
11504 ConstraintRelidTypidNameIndexId,
11508 {
11513 else
11514 {
11515 ObjectAddress addr;
11516 SysScanDesc scan2;
11517 ScanKeyData key2;
11523 /*
11524 * First we must delete the dependency record that binds the
11525 * constraint records together.
11526 */
11529 DEPENDENCY_INTERNAL,
11530 ConstraintRelationId,
11534 /*
11535 * Now search for the triggers for this constraint and set
11536 * them up for deletion too
11537 */
11539 Anum_pg_trigger_tgconstraint,
11545 {
11549 }
11551 }
11552 }
11553 /* make the dependency deletions visible */
11556 PERFORM_DELETION_INTERNAL);
11560 }
11564 }
11566 /*
11567 * GetForeignKeyActionTriggers
11568 * Returns delete and update "action" triggers of the given relation
11569 * belonging to the given constraint
11570 */
11571 static void
11576 {
11577 ScanKeyData key;
11578 SysScanDesc scan;
11579 HeapTuple trigtup;
11583 Anum_pg_trigger_tgconstraint,
11590 {
11597 /* Only ever look at "action" triggers on the PK side. */
11601 {
11604 }
11606 {
11609 }
11610 #ifndef USE_ASSERT_CHECKING
11611 /* In an assert-enabled build, continue looking to find duplicates */
11614 #endif
11615 }
11619 conoid);
11622 conoid);
11625 }
11627 /*
11628 * GetForeignKeyCheckTriggers
11629 * Returns insert and update "check" triggers of the given relation
11630 * belonging to the given constraint
11631 */
11632 static void
11637 {
11638 ScanKeyData key;
11639 SysScanDesc scan;
11640 HeapTuple trigtup;
11644 Anum_pg_trigger_tgconstraint,
11651 {
11658 /* Only ever look at "check" triggers on the FK side. */
11662 {
11665 }
11667 {
11670 }
11671 #ifndef USE_ASSERT_CHECKING
11672 /* In an assert-enabled build, continue looking to find duplicates. */
11675 #endif
11676 }
11680 conoid);
11683 conoid);
11686 }
11688 /*
11689 * ALTER TABLE ALTER CONSTRAINT
11690 *
11691 * Update the attributes of a constraint.
11692 *
11693 * Currently only works for Foreign Key constraints.
11694 *
11695 * If the constraint is modified, returns its address; otherwise, return
11696 * InvalidObjectAddress.
11697 */
11698 static ObjectAddress
11701 {
11703 Relation conrel;
11704 Relation tgrel;
11705 SysScanDesc scan;
11707 HeapTuple contuple;
11708 Form_pg_constraint currcon;
11709 ObjectAddress address;
11718 /*
11719 * Find and check the target constraint
11720 */
11722 Anum_pg_constraint_conrelid,
11726 Anum_pg_constraint_contypid,
11730 Anum_pg_constraint_conname,
11736 /* There can be at most one matching row */
11750 /*
11751 * If it's not the topmost constraint, raise an error.
11752 *
11753 * Altering a non-topmost constraint leaves some triggers untouched, since
11754 * they are not directly connected to this constraint; also, pg_dump would
11755 * ignore the deferrability status of the individual constraint, since it
11756 * only dumps topmost constraints. Avoid these problems by refusing this
11757 * operation and telling the user to alter the parent constraint instead.
11758 */
11760 {
11761 HeapTuple tp;
11766 /* Loop to find the topmost constraint */
11768 {
11771 /* If no parent, this is the constraint we want */
11773 {
11778 }
11782 }
11792 }
11794 /*
11795 * Do the actual catalog work. We can skip changing if already in the
11796 * desired state, but not if a partitioned table: partitions need to be
11797 * processed regardless, in case they had the constraint locally changed.
11798 */
11803 {
11807 }
11809 /*
11810 * ATExecAlterConstrRecurse already invalidated relcache for the relations
11811 * having the constraint itself; here we also invalidate for relations
11812 * that have any triggers that are part of the constraint.
11813 */
11823 }
11825 /*
11826 * Recursive subroutine of ATExecAlterConstraint. Returns true if the
11827 * constraint is altered.
11828 *
11829 * *otherrelids is appended OIDs of relations containing affected triggers.
11830 *
11831 * Note that we must recurse even when the values are correct, in case
11832 * indirect descendants have had their constraints altered locally.
11833 * (This could be avoided if we forbade altering constraints in partitions
11834 * but existing releases don't do that.)
11835 */
11836 static bool
11839 LOCKMODE lockmode)
11840 {
11841 Form_pg_constraint currcon;
11842 Oid conoid;
11843 Oid refrelid;
11846 /* since this function recurses, it could be driven to stack overflow */
11853 /*
11854 * Update pg_constraint with the flags from cmdcon.
11855 *
11856 * If called to modify a constraint that's already in the desired state,
11857 * silently do nothing.
11858 */
11861 {
11862 HeapTuple copyTuple;
11863 Form_pg_constraint copy_con;
11864 HeapTuple tgtuple;
11865 ScanKeyData tgkey;
11866 SysScanDesc tgscan;
11880 /* Make new constraint flags visible to others */
11883 /*
11884 * Now we need to update the multiple entries in pg_trigger that
11885 * implement the constraint.
11886 */
11888 Anum_pg_trigger_tgconstraint,
11894 {
11896 Form_pg_trigger copy_tg;
11897 HeapTuple tgCopyTuple;
11899 /*
11900 * Remember OIDs of other relation(s) involved in FK constraint.
11901 * (Note: it's likely that we could skip forcing a relcache inval
11902 * for other rels that don't have a trigger whose properties
11903 * change, but let's be conservative.)
11904 */
11909 /*
11910 * Update deferrability of RI_FKey_noaction_del,
11911 * RI_FKey_noaction_upd, RI_FKey_check_ins and RI_FKey_check_upd
11912 * triggers, but not others; see createForeignKeyActionTriggers
11913 * and CreateFKCheckTrigger.
11914 */
11931 }
11934 }
11936 /*
11937 * If the table at either end of the constraint is partitioned, we need to
11938 * recurse and handle every constraint that is a child of this one.
11939 *
11940 * (This assumes that the recurse flag is forcibly set for partitioned
11941 * tables, and not set for legacy inheritance, though we don't check for
11942 * that here.)
11943 */
11946 {
11947 ScanKeyData pkey;
11948 SysScanDesc pscan;
11949 HeapTuple childtup;
11952 Anum_pg_constraint_conparentid,
11960 {
11962 Relation childrel;
11968 }
11971 }
11974 }
11976 /*
11977 * ALTER TABLE VALIDATE CONSTRAINT
11978 *
11979 * XXX The reason we handle recursion here rather than at Phase 1 is because
11980 * there's no good way to skip recursing when handling foreign keys: there is
11981 * no need to lock children in that case, yet we wouldn't be able to avoid
11982 * doing so at that level.
11983 *
11984 * Return value is the address of the validated constraint. If the constraint
11985 * was already validated, InvalidObjectAddress is returned.
11986 */
11987 static ObjectAddress
11990 {
11991 Relation conrel;
11992 SysScanDesc scan;
11994 HeapTuple tuple;
11995 Form_pg_constraint con;
11996 ObjectAddress address;
12000 /*
12001 * Find and check the target constraint
12002 */
12004 Anum_pg_constraint_conrelid,
12008 Anum_pg_constraint_contypid,
12012 Anum_pg_constraint_conname,
12018 /* There can be at most one matching row */
12039 {
12041 HeapTuple copyTuple;
12042 Form_pg_constraint copy_con;
12045 {
12049 /* Queue validation for phase 3 */
12051 /* for now this is all we need */
12062 /* Find or create work queue entry for this table */
12066 /*
12067 * We disallow creating invalid foreign keys to or from
12068 * partitioned tables, so ignoring the recursion bit is okay.
12069 */
12070 }
12072 {
12076 Datum val;
12079 /*
12080 * If we're recursing, the parent has already done this, so skip
12081 * it. Also, if the constraint is a NO INHERIT constraint, we
12082 * shouldn't try to look for it in the children.
12083 */
12088 /*
12089 * For CHECK constraints, we must ensure that we only mark the
12090 * constraint as validated on the parent if it's already validated
12091 * on the children.
12092 *
12093 * We recurse before validating on the parent, to reduce risk of
12094 * deadlocks.
12095 */
12097 {
12099 Relation childrel;
12104 /*
12105 * If we are told not to recurse, there had better not be any
12106 * child tables, because we can't mark the constraint on the
12107 * parent valid unless it is valid for all child tables.
12108 */
12114 /* find_all_inheritors already got lock */
12120 }
12122 /* Queue validation for phase 3 */
12131 Anum_pg_constraint_conbin);
12135 /* Find or create work queue entry for this table */
12139 /*
12140 * Invalidate relcache so that others see the new validated
12141 * constraint.
12142 */
12144 }
12146 /*
12147 * Now update the catalog, while we have the door open.
12148 */
12159 }
12160 else
12168 }
12171 /*
12172 * transformColumnNameList - transform list of column names
12173 *
12174 * Lookup each name and return its attnum and, optionally, type and collation
12175 * OIDs
12176 *
12177 * Note: the name of this function suggests that it's general-purpose,
12178 * but actually it's only used to look up names appearing in foreign-key
12179 * clauses. The error messages would need work to use it in other cases,
12180 * and perhaps the validity checks as well.
12181 */
12182 static int
12185 {
12191 {
12193 HeapTuple atttuple;
12194 Form_pg_attribute attform;
12201 attname)));
12211 INDEX_MAX_KEYS)));
12218 attnum++;
12219 }
12222 }
12224 /*
12225 * transformFkeyGetPrimaryKey -
12226 *
12227 * Look up the names, attnums, types, and collations of the primary key attributes
12228 * for the pkrel. Also return the index OID and index opclasses of the
12229 * index supporting the primary key. Also return whether the index has
12230 * WITHOUT OVERLAPS.
12231 *
12232 * All parameters except pkrel are output parameters. Also, the function
12233 * return value is the number of attributes in the primary key.
12234 *
12235 * Used when the column list in the REFERENCES specification is omitted.
12236 */
12237 static int
12242 {
12247 Datum indclassDatum;
12251 /*
12252 * Get the list of index OIDs for the table from the relcache, and look up
12253 * each one in the pg_index syscache until we find one marked primary key
12254 * (hopefully there isn't more than one such). Insist it's valid, too.
12255 */
12261 {
12269 {
12270 /*
12271 * Refuse to use a deferrable primary key. This is per SQL spec,
12272 * and there would be a lot of interesting semantic problems if we
12273 * tried to allow it.
12274 */
12283 }
12285 }
12289 /*
12290 * Check that we found it
12291 */
12298 /* Must get indclass the hard way */
12300 Anum_pg_index_indclass);
12303 /*
12304 * Now build the list of PK attributes from the indkey definition (we
12305 * assume a primary key cannot have expressional elements)
12306 */
12309 {
12318 }
12325 }
12327 /*
12328 * transformFkeyCheckAttrs -
12329 *
12330 * Validate that the 'attnums' columns in the 'pkrel' relation are valid to
12331 * reference as part of a foreign key constraint.
12332 *
12333 * Returns the OID of the unique index supporting the constraint and
12334 * populates the caller-provided 'opclasses' array with the opclasses
12335 * associated with the index columns. Also sets whether the index
12336 * uses WITHOUT OVERLAPS.
12337 *
12338 * Raises an ERROR on validation failure.
12339 */
12340 static Oid
12345 {
12352 j;
12354 /*
12355 * Reject duplicate appearances of columns in the referenced-columns list.
12356 * Such a case is forbidden by the SQL standard, and even if we thought it
12357 * useful to allow it, there would be ambiguity about how to match the
12358 * list to unique indexes (in particular, it'd be unclear which index
12359 * opclass goes with which FK column).
12360 */
12362 {
12364 {
12369 }
12370 }
12372 /*
12373 * Get the list of index OIDs for the table from the relcache, and look up
12374 * each one in the pg_index syscache, and match unique indexes to the list
12375 * of attnums we are given.
12376 */
12380 {
12381 HeapTuple indexTuple;
12382 Form_pg_index indexStruct;
12390 /*
12391 * Must have the right number of columns; must be unique (or if
12392 * temporal then exclusion instead) and not a partial index; forget it
12393 * if there are any expressions, too. Invalid indexes are out as well.
12394 */
12400 {
12401 Datum indclassDatum;
12404 /* Must get indclass the hard way */
12406 Anum_pg_index_indclass);
12409 /*
12410 * The given attnum list may match the index columns in any order.
12411 * Check for a match, and extract the appropriate opclasses while
12412 * we're at it.
12413 *
12414 * We know that attnums[] is duplicate-free per the test at the
12415 * start of this function, and we checked above that the number of
12416 * index columns agrees, so if we find a match for each attnums[]
12417 * entry then we must have a one-to-one match in some order.
12418 */
12420 {
12423 {
12425 {
12429 }
12430 }
12433 }
12434 /* The last attribute in the index must be the PERIOD FK part */
12436 {
12440 }
12442 /*
12443 * Refuse to use a deferrable unique/primary key. This is per SQL
12444 * spec, and there would be a lot of interesting semantic problems
12445 * if we tried to allow it.
12446 */
12448 {
12449 /*
12450 * Remember that we found an otherwise matching index, so that
12451 * we can generate a more appropriate error message.
12452 */
12455 }
12457 /* We need to know whether the index has WITHOUT OVERLAPS */
12460 }
12464 }
12467 {
12473 else
12478 }
12483 }
12485 /*
12486 * findFkeyCast -
12487 *
12488 * Wrapper around find_coercion_pathway() for ATAddForeignKeyConstraint().
12489 * Caller has equal regard for binary coercibility and for an exact match.
12490 */
12491 static CoercionPathType
12493 {
12494 CoercionPathType ret;
12497 {
12500 }
12501 else
12502 {
12506 /* A previously-relied-upon cast is now gone. */
12509 }
12512 }
12514 /*
12515 * Permissions checks on the referenced table for ADD FOREIGN KEY
12516 *
12517 * Note: we have already checked that the user owns the referencing table,
12518 * else we'd have failed much earlier; no additional checks are needed for it.
12519 */
12520 static void
12522 {
12524 AclResult aclresult;
12527 /* Okay if we have relation-level REFERENCES permission */
12529 ACL_REFERENCES);
12532 /* Else we must have REFERENCES on each column */
12534 {
12540 }
12541 }
12543 /*
12544 * Scan the existing rows in a table to verify they meet a proposed FK
12545 * constraint.
12546 *
12547 * Caller must have opened and locked both relations appropriately.
12548 */
12549 static void
12551 Relation rel,
12552 Relation pkrel,
12553 Oid pkindOid,
12554 Oid constraintOid,
12556 {
12558 TableScanDesc scan;
12560 Snapshot snapshot;
12561 MemoryContext oldcxt;
12562 MemoryContext perTupCxt;
12567 /*
12568 * Build a trigger call structure; we'll need it either way.
12569 */
12579 /* we needn't fill in remaining fields */
12581 /*
12582 * See if we can do it with a single LEFT JOIN query. A false result
12583 * indicates we must proceed with the fire-the-trigger method. We can't do
12584 * a LEFT JOIN for temporal FKs yet, but we can once we support temporal
12585 * left joins.
12586 */
12590 /*
12591 * Scan through each tuple, calling RI_FKey_check_ins (insert trigger) as
12592 * if that tuple had just been inserted. If any of those fail, it should
12593 * ereport(ERROR) and that's that.
12594 */
12601 ALLOCSET_SMALL_SIZES);
12605 {
12611 /*
12612 * Make a call to the trigger function
12613 *
12614 * No parameters are passed, but we do set a context
12615 */
12618 /*
12619 * We assume RI_FKey_check_ins won't look at flinfo...
12620 */
12633 }
12640 }
12642 /*
12643 * CreateFKCheckTrigger
12644 * Creates the insert (on_insert=true) or update "check" trigger that
12645 * implements a given foreign key
12646 *
12647 * Returns the OID of the so created trigger.
12648 */
12649 static Oid
12653 {
12654 ObjectAddress trigAddress;
12657 /*
12658 * Note: for a self-referential FK (referencing and referenced tables are
12659 * the same), it is important that the ON UPDATE action fires before the
12660 * CHECK action, since both triggers will fire on the same row during an
12661 * UPDATE event; otherwise the CHECK trigger will be checking a non-final
12662 * state of the row. Triggers fire in name order, so we ensure this by
12663 * using names like "RI_ConstraintTrigger_a_NNNN" for the action triggers
12664 * and "RI_ConstraintTrigger_c_NNNN" for the check triggers.
12665 */
12672 /* Either ON INSERT or ON UPDATE */
12674 {
12677 }
12678 else
12679 {
12682 }
12698 /* Make changes-so-far visible */
12702 }
12704 /*
12705 * createForeignKeyActionTriggers
12706 * Create the referenced-side "action" triggers that implement a foreign
12707 * key.
12708 *
12709 * Returns the OIDs of the so created triggers in *deleteTrigOid and
12710 * *updateTrigOid.
12711 */
12712 static void
12717 {
12719 ObjectAddress trigAddress;
12721 /*
12722 * Build and execute a CREATE CONSTRAINT TRIGGER statement for the ON
12723 * DELETE action on the referenced table.
12724 */
12740 {
12770 }
12779 /* Make changes-so-far visible */
12782 /*
12783 * Build and execute a CREATE CONSTRAINT TRIGGER statement for the ON
12784 * UPDATE action on the referenced table.
12785 */
12801 {
12831 }
12839 }
12841 /*
12842 * createForeignKeyCheckTriggers
12843 * Create the referencing-side "check" triggers that implement a foreign
12844 * key.
12845 *
12846 * Returns the OIDs of the so created triggers in *insertTrigOid and
12847 * *updateTrigOid.
12848 */
12849 static void
12852 Oid indexOid,
12855 {
12862 }
12864 /*
12865 * ALTER TABLE DROP CONSTRAINT
12866 *
12867 * Like DROP COLUMN, we can't use the normal ALTER TABLE recursion mechanism.
12868 */
12869 static void
12873 {
12874 Relation conrel;
12875 SysScanDesc scan;
12877 HeapTuple tuple;
12882 /*
12883 * Find and drop the target constraint
12884 */
12886 Anum_pg_constraint_conrelid,
12890 Anum_pg_constraint_contypid,
12894 Anum_pg_constraint_conname,
12900 /* There can be at most one matching row */
12902 {
12906 }
12911 {
12917 else
12921 }
12924 }
12926 /*
12927 * Remove a constraint, using its pg_constraint tuple
12928 *
12929 * Implementation for ALTER TABLE DROP CONSTRAINT and ALTER TABLE ALTER COLUMN
12930 * DROP NOT NULL.
12931 *
12932 * Returns the address of the constraint being removed.
12933 */
12934 static ObjectAddress
12937 LOCKMODE lockmode)
12938 {
12939 Relation conrel;
12940 Form_pg_constraint con;
12941 ObjectAddress conobj;
12947 /* Guard against stack overflow due to overly deep inheritance tree. */
12950 /* At top level, permission check was done in ATPrepCmd, else do it */
12960 /* Don't allow drop of inherited constraints */
12967 /*
12968 * Reset pg_constraint.attnotnull, if this is a not-null constraint.
12969 *
12970 * While doing that, we're in a good position to disallow dropping a not-
12971 * null constraint underneath a primary key, a replica identity index, or
12972 * a generated identity column.
12973 */
12975 {
12980 HeapTuple atttup;
12981 Form_pg_attribute attForm;
12983 /* save column name for recursion step */
12986 /*
12987 * Disallow if it's in the primary key. For partitioned tables we
12988 * cannot rely solely on RelationGetIndexAttrBitmap, because it'll
12989 * return NULL if the primary key is invalid; but we still need to
12990 * protect not-null constraints under such a constraint, so check the
12991 * slow way.
12992 */
12997 {
13001 {
13009 }
13010 }
13019 /* Disallow if it's in the replica identity */
13027 /* Disallow if it's a GENERATED AS IDENTITY column */
13041 /* All good -- reset attnotnull if needed */
13043 {
13046 }
13049 }
13053 /*
13054 * If it's a foreign-key constraint, we'd better lock the referenced table
13055 * and check that that's not in use, just as we've already done for the
13056 * constrained table (else we might, eg, be dropping a trigger that has
13057 * unfired events). But we can/must skip that in the self-referential
13058 * case.
13059 */
13062 {
13063 Relation frel;
13065 /* Must match lock taken by RemoveTriggerById: */
13069 }
13071 /*
13072 * Perform the actual constraint deletion
13073 */
13077 /*
13078 * For partitioned tables, non-CHECK, non-NOT-NULL inherited constraints
13079 * are dropped via the dependency mechanism, so we're done here.
13080 */
13084 {
13087 }
13089 /*
13090 * Propagate to children as appropriate. Unlike most other ALTER
13091 * routines, we have to do this one level of recursion at a time; we can't
13092 * use find_all_inheritors to do it in one pass.
13093 */
13096 else
13100 {
13101 Relation childrel;
13102 HeapTuple tuple;
13103 Form_pg_constraint childcon;
13105 /* find_inheritance_children already got lock */
13109 /*
13110 * We search for not-null constraints by column name, and others by
13111 * constraint name.
13112 */
13114 {
13119 }
13120 else
13121 {
13122 SysScanDesc scan;
13126 Anum_pg_constraint_conrelid,
13130 Anum_pg_constraint_contypid,
13134 Anum_pg_constraint_conname,
13139 /* There can only be one, so no need to loop */
13145 constrName,
13149 }
13153 /* Right now only CHECK and not-null constraints can be inherited */
13163 {
13164 /*
13165 * If the child constraint has other definition sources, just
13166 * decrement its inheritance count; if not, recurse to delete it.
13167 */
13169 {
13170 /* Time to delete this child constraint, too */
13173 lockmode);
13174 }
13175 else
13176 {
13177 /* Child constraint must survive my deletion */
13181 /* Make update visible */
13183 }
13184 }
13185 else
13186 {
13187 /*
13188 * If we were told to drop ONLY in this table (no recursion) and
13189 * there are no further parents for this constraint, we need to
13190 * mark the inheritors' constraints as locally defined rather than
13191 * inherited.
13192 */
13199 /* Make update visible */
13201 }
13206 }
13211 }
13213 /*
13214 * ALTER COLUMN TYPE
13215 *
13216 * Unlike other subcommand types, we do parse transformation for ALTER COLUMN
13217 * TYPE during phase 1 --- the AlterTableCmd passed in here is already
13218 * transformed (and must be, because we rely on some transformed fields).
13219 *
13220 * The point of this is that the execution of all ALTER COLUMN TYPEs for a
13221 * table will be done "in parallel" during phase 3, so all the USING
13222 * expressions should be parsed assuming the original column types. Also,
13223 * this allows a USING expression to refer to a field that will be dropped.
13224 *
13225 * To make this work safely, AT_PASS_DROP then AT_PASS_ALTER_TYPE must be
13226 * the first two execution steps in phase 2; they must not see the effects
13227 * of any other subcommand types, since the USING expressions are parsed
13228 * against the unmodified table's state.
13229 */
13230 static void
13236 {
13241 HeapTuple tuple;
13242 Form_pg_attribute attTup;
13243 AttrNumber attnum;
13244 Oid targettype;
13245 int32 targettypmod;
13246 Oid targetcollid;
13249 AclResult aclresult;
13257 /* lookup the attribute so we can check inheritance status */
13267 /* Can't alter a system attribute */
13272 colName)));
13274 /*
13275 * Cannot specify USING when altering type of a generated column, because
13276 * that would violate the generation expression.
13277 */
13284 /*
13285 * Don't alter inherited columns. At outer level, there had better not be
13286 * any inherited definition; when recursing, we assume this was checked at
13287 * the parent level (see below).
13288 */
13293 colName)));
13295 /* Don't alter columns used in the partition key */
13301 errmsg("cannot alter column \"%s\" because it is part of the partition key of relation \"%s\"",
13304 /* Look up the target type */
13311 /* And the collation */
13314 /* make sure datatype is legal for a column */
13321 {
13322 /*
13323 * Set up an expression to transform the old data value to the new
13324 * type. If a USING option was given, use the expression as
13325 * transformed by transformAlterTableStmt, else just take the old
13326 * value and try to coerce it. We do this first so that type
13327 * incompatibility can be detected before we waste effort, and because
13328 * we need the expression to be parsed against the original table row
13329 * type.
13330 */
13332 {
13337 }
13342 COERCION_ASSIGNMENT,
13343 COERCE_IMPLICIT_CAST,
13346 {
13347 /* error text depends on whether USING was specified or not */
13355 else
13361 /* translator: USING is SQL, don't translate it */
13366 }
13368 /* Fix collations after all else */
13371 /* Plan the expr now so we can accurately assess the need to rewrite. */
13374 /*
13375 * Add a work queue item to make ATRewriteTable update the column
13376 * contents.
13377 */
13386 }
13394 {
13395 /*
13396 * For relations without storage, do this check now. Regular tables
13397 * will check it later when the table is being rewritten.
13398 */
13400 }
13404 /*
13405 * Recurse manually by queueing a new command for each child, if
13406 * necessary. We cannot apply ATSimpleRecursion here because we need to
13407 * remap attribute numbers in the USING expression, if any.
13408 *
13409 * If we are told not to recurse, there had better not be any child
13410 * tables; else the alter would put them out of step.
13411 */
13413 {
13423 /*
13424 * find_all_inheritors does the recursive search of the inheritance
13425 * hierarchy, so all we have to do is process all of the relids in the
13426 * list that it returns.
13427 */
13429 {
13432 Relation childrel;
13433 HeapTuple childtuple;
13434 Form_pg_attribute childattTup;
13439 /* find_all_inheritors already got lock */
13443 /*
13444 * Verify that the child doesn't have any inherited definitions of
13445 * this column that came from outside this inheritance hierarchy.
13446 * (renameatt makes a similar test, though in a different way
13447 * because of its different recursion mechanism.)
13448 */
13450 colName);
13466 /*
13467 * Remap the attribute numbers. If no USING expression was
13468 * specified, there is no need for this step.
13469 */
13471 {
13475 /* create a copy to scribble on */
13484 attmap,
13492 }
13495 }
13496 }
13502 colName)));
13506 }
13508 /*
13509 * When the data type of a column is changed, a rewrite might not be required
13510 * if the new type is sufficiently identical to the old one, and the USING
13511 * clause isn't trying to insert some other value. It's safe to skip the
13512 * rewrite in these cases:
13513 *
13514 * - the old type is binary coercible to the new type
13515 * - the new type is an unconstrained domain over the old type
13516 * - {NEW,OLD} or {OLD,NEW} is {timestamptz,timestamp} and the timezone is UTC
13517 *
13518 * In the case of a constrained domain, we could get by with scanning the
13519 * table and checking the constraint rather than actually rewriting it, but we
13520 * don't currently try to do that.
13521 */
13522 static bool
13524 {
13528 {
13529 /* only one varno, so no need to check that */
13535 {
13541 }
13543 {
13547 {
13552 else
13557 }
13558 }
13559 else
13561 }
13562 }
13564 /*
13565 * ALTER COLUMN .. SET DATA TYPE
13566 *
13567 * Return the address of the modified column.
13568 */
13569 static ObjectAddress
13572 {
13576 HeapTuple heapTup;
13577 Form_pg_attribute attTup,
13578 attOldTup;
13579 AttrNumber attnum;
13580 HeapTuple typeTuple;
13581 Form_pg_type tform;
13582 Oid targettype;
13583 int32 targettypmod;
13584 Oid targetcollid;
13586 Relation attrelation;
13587 Relation depRel;
13589 SysScanDesc scan;
13590 HeapTuple depTup;
13591 ObjectAddress address;
13593 /*
13594 * Clear all the missing values if we're rewriting the table, since this
13595 * renders them pointless.
13596 */
13598 {
13599 Relation newrel;
13604 /* make sure we don't conflict with later attribute modifications */
13606 }
13610 /* Look up the target column */
13621 /* Check for multiple ALTER TYPE on same column --- can't cope */
13627 colName)));
13629 /* Look up the target type (should not fail, since prep found it) */
13633 /* And the collation */
13636 /*
13637 * If there is a default expression for the column, get it and ensure we
13638 * can coerce it to the new datatype. (We must do this before changing
13639 * the column type, because build_column_default itself will try to
13640 * coerce, and will not issue the error message we want if it fails.)
13641 *
13642 * We remove any implicit coercion steps at the top level of the old
13643 * default expression; this has been agreed to satisfy the principle of
13644 * least surprise. (The conversion to the new column type should act like
13645 * it started from what the user sees as the stored expression, and the
13646 * implicit coercions aren't going to be shown.)
13647 */
13649 {
13656 COERCION_ASSIGNMENT,
13657 COERCE_IMPLICIT_CAST,
13660 {
13666 else
13671 }
13672 }
13673 else
13676 /*
13677 * Find everything that depends on the column (constraints, indexes, etc),
13678 * and record enough information to let us recreate the objects.
13679 *
13680 * The actual recreation does not happen here, but only after we have
13681 * performed all the individual ALTER TYPE operations. We have to save
13682 * the info before executing ALTER TYPE, though, else the deparser will
13683 * get confused.
13684 */
13687 /*
13688 * Now scan for dependencies of this column on other things. The only
13689 * things we should find are the dependency on the column datatype and
13690 * possibly a collation dependency. Those can be removed.
13691 */
13695 Anum_pg_depend_classid,
13699 Anum_pg_depend_objid,
13703 Anum_pg_depend_objsubid,
13711 {
13713 ObjectAddress foundObject;
13730 }
13736 /*
13737 * Here we go --- change the recorded column type and collation. (Note
13738 * heapTup is a copy of the syscache entry, so okay to scribble on.) First
13739 * fix up the missing value if any.
13740 */
13742 {
13743 Datum missingval;
13746 /* if rewrite is true the missing value should already be cleared */
13749 /* Get the missing value datum */
13751 Anum_pg_attribute_attmissingval,
13755 /* if it's a null array there is nothing to do */
13758 {
13759 /*
13760 * Get the datum out of the array and repack it in a new array
13761 * built with the new type data. We assume that since the table
13762 * doesn't need rewriting, the actual Datum doesn't need to be
13763 * changed, only the array metadata.
13764 */
13771 HeapTuple newTup;
13783 targettype,
13797 }
13798 }
13820 /* Install dependencies on new datatype and collation */
13824 /*
13825 * Drop any pg_statistic entry for the column, since it's now wrong type
13826 */
13832 /*
13833 * Update the default, if present, by brute force --- remove and re-add
13834 * the default. Probably unsafe to take shortcuts, since the new version
13835 * may well have additional dependencies. (It's okay to do this now,
13836 * rather than after other ALTER TYPE commands, since the default won't
13837 * depend on other column types.)
13838 */
13840 {
13841 /*
13842 * If it's a GENERATED default, drop its dependency records, in
13843 * particular its INTERNAL dependency on the column, which would
13844 * otherwise cause dependency.c to refuse to perform the deletion.
13845 */
13847 {
13854 }
13856 /*
13857 * Make updates-so-far visible, particularly the new pg_attribute row
13858 * which will be updated again.
13859 */
13862 /*
13863 * We use RESTRICT here for safety, but at present we do not expect
13864 * anything to depend on the default.
13865 */
13870 }
13875 /* Cleanup */
13879 }
13881 /*
13882 * Subroutine for ATExecAlterColumnType and ATExecSetExpression: Find everything
13883 * that depends on the column (constraints, indexes, etc), and record enough
13884 * information to let us recreate the objects.
13885 */
13886 static void
13889 {
13890 Relation depRel;
13892 SysScanDesc scan;
13893 HeapTuple depTup;
13900 Anum_pg_depend_refclassid,
13904 Anum_pg_depend_refobjid,
13908 Anum_pg_depend_refobjsubid,
13916 {
13918 ObjectAddress foundObject;
13925 {
13927 {
13932 {
13935 }
13937 {
13938 /*
13939 * This must be a SERIAL column's sequence. We need
13940 * not do anything to it.
13941 */
13943 }
13944 else
13945 {
13946 /* Not expecting any other direct dependencies... */
13949 }
13951 }
13960 /*
13961 * A new-style SQL function can depend on a column, if that
13962 * column is referenced in the parsed function body. Ideally
13963 * we'd automatically update the function by deparsing and
13964 * reparsing it, but that's risky and might well fail anyhow.
13965 * FIXME someday.
13966 *
13967 * This is only a problem for AT_AlterColumnType, not
13968 * AT_SetExpression.
13969 */
13976 colName)));
13981 /*
13982 * View/rule bodies have pretty much the same issues as
13983 * function bodies. FIXME someday.
13984 */
13991 colName)));
13996 /*
13997 * A trigger can depend on a column because the column is
13998 * specified as an update target, or because the column is
13999 * used in the trigger's WHEN condition. The first case would
14000 * not require any extra work, but the second case would
14001 * require updating the WHEN expression, which has the same
14002 * issues as above. Since we can't easily tell which case
14003 * applies, we punt for both. FIXME someday.
14004 */
14011 colName)));
14016 /*
14017 * A policy can depend on a column because the column is
14018 * specified in the policy's USING or WITH CHECK qual
14019 * expressions. It might be possible to rewrite and recheck
14020 * the policy expression, but punt for now. It's certainly
14021 * easy enough to remove and recreate the policy; still, FIXME
14022 * someday.
14023 */
14030 colName)));
14034 {
14039 {
14040 /*
14041 * Ignore the column's own default expression. The
14042 * caller deals with it.
14043 */
14044 }
14045 else
14046 {
14047 /*
14048 * This must be a reference from the expression of a
14049 * generated column elsewhere in the same table.
14050 * Changing the type/generated expression of a column
14051 * that is used by a generated column is not allowed
14052 * by SQL standard, so just punt for now. It might be
14053 * doable with some thinking and effort.
14054 */
14060 colName,
14064 }
14066 }
14070 /*
14071 * Give the extended-stats machinery a chance to fix anything
14072 * that this column type change would break.
14073 */
14079 /*
14080 * Column reference in a PUBLICATION ... FOR TABLE ... WHERE
14081 * clause. Same issues as above. FIXME someday.
14082 */
14089 colName)));
14094 /*
14095 * We don't expect any other sorts of objects to depend on a
14096 * column.
14097 */
14101 }
14102 }
14106 }
14108 /*
14109 * Subroutine for ATExecAlterColumnType: remember that a replica identity
14110 * needs to be reset.
14111 */
14112 static void
14114 {
14122 }
14124 /*
14125 * Subroutine for ATExecAlterColumnType: remember any clustered index.
14126 */
14127 static void
14129 {
14137 }
14139 /*
14140 * Subroutine for ATExecAlterColumnType: remember that a constraint needs
14141 * to be rebuilt (which we might already know).
14142 */
14143 static void
14145 {
14146 /*
14147 * This de-duplication check is critical for two independent reasons: we
14148 * mustn't try to recreate the same constraint twice, and if a constraint
14149 * depends on more than one column whose type is to be altered, we must
14150 * capture its definition string before applying any of the column type
14151 * changes. ruleutils.c will get confused if we ask again later.
14152 */
14154 {
14155 /* OK, capture the constraint's existing definition string */
14157 Oid indoid;
14159 /*
14160 * It is critical to create not-null constraints ahead of primary key
14161 * indexes; otherwise, the not-null constraint would be created by the
14162 * primary key, and the constraint name would be wrong.
14163 */
14165 {
14170 }
14171 else
14172 {
14175 conoid);
14177 defstring);
14178 }
14180 /*
14181 * For the index of a constraint, if any, remember if it is used for
14182 * the table's replica identity or if it is a clustered index, so that
14183 * ATPostAlterTypeCleanup() can queue up commands necessary to restore
14184 * those properties.
14185 */
14188 {
14191 }
14192 }
14193 }
14195 /*
14196 * Subroutine for ATExecAlterColumnType: remember that an index needs
14197 * to be rebuilt (which we might already know).
14198 */
14199 static void
14201 {
14202 /*
14203 * This de-duplication check is critical for two independent reasons: we
14204 * mustn't try to recreate the same index twice, and if an index depends
14205 * on more than one column whose type is to be altered, we must capture
14206 * its definition string before applying any of the column type changes.
14207 * ruleutils.c will get confused if we ask again later.
14208 */
14210 {
14211 /*
14212 * Before adding it as an index-to-rebuild, we'd better see if it
14213 * belongs to a constraint, and if so rebuild the constraint instead.
14214 * Typically this check fails, because constraint indexes normally
14215 * have only dependencies on their constraint. But it's possible for
14216 * such an index to also have direct dependencies on table columns,
14217 * for example with a partial exclusion constraint.
14218 */
14222 {
14224 }
14225 else
14226 {
14227 /* OK, capture the index's existing definition string */
14231 indoid);
14233 defstring);
14235 /*
14236 * Remember if this index is used for the table's replica identity
14237 * or if it is a clustered index, so that ATPostAlterTypeCleanup()
14238 * can queue up commands necessary to restore those properties.
14239 */
14242 }
14243 }
14244 }
14246 /*
14247 * Subroutine for ATExecAlterColumnType: remember that a statistics object
14248 * needs to be rebuilt (which we might already know).
14249 */
14250 static void
14252 {
14253 /*
14254 * This de-duplication check is critical for two independent reasons: we
14255 * mustn't try to recreate the same statistics object twice, and if the
14256 * statistics object depends on more than one column whose type is to be
14257 * altered, we must capture its definition string before applying any of
14258 * the type changes. ruleutils.c will get confused if we ask again later.
14259 */
14261 {
14262 /* OK, capture the statistics object's existing definition string */
14266 stxoid);
14268 defstring);
14269 }
14270 }
14272 /*
14273 * Cleanup after we've finished all the ALTER TYPE or SET EXPRESSION
14274 * operations for a particular relation. We have to drop and recreate all the
14275 * indexes and constraints that depend on the altered columns. We do the
14276 * actual dropping here, but re-creation is managed by adding work queue
14277 * entries to do those steps later.
14278 */
14279 static void
14281 {
14282 ObjectAddress obj;
14287 /*
14288 * Collect all the constraints and indexes to drop so we can process them
14289 * in a single call. That way we don't have to worry about dependencies
14290 * among them.
14291 */
14294 /*
14295 * Re-parse the index and constraint definitions, and attach them to the
14296 * appropriate work queue entries. We do this before dropping because in
14297 * the case of a FOREIGN KEY constraint, we might not yet have exclusive
14298 * lock on the table the constraint is attached to, and we need to get
14299 * that before reparsing/dropping.
14300 *
14301 * We can't rely on the output of deparsing to tell us which relation to
14302 * operate on, because concurrent activity might have made the name
14303 * resolve differently. Instead, we've got to use the OID of the
14304 * constraint or index we're processing to figure out which relation to
14305 * operate on.
14306 */
14309 {
14311 HeapTuple tup;
14312 Form_pg_constraint con;
14313 Oid relid;
14314 Oid confrelid;
14324 else
14325 {
14326 /* must be a domain constraint */
14330 }
14339 /*
14340 * If the constraint is inherited (only), we don't want to inject a
14341 * new definition here; it'll get recreated when
14342 * ATAddCheckNNConstraint recurses from adding the parent table's
14343 * constraint. But we had to carry the info this far so that we can
14344 * drop the constraint below.
14345 */
14349 /*
14350 * When rebuilding an FK constraint that references the table we're
14351 * modifying, we might not yet have any lock on the FK's table, so get
14352 * one now. We'll need AccessExclusiveLock for the DROP CONSTRAINT
14353 * step, so there's no value in asking for anything weaker.
14354 */
14361 }
14364 {
14366 Oid relid;
14375 }
14377 /* add dependencies for new statistics */
14380 {
14382 Oid relid;
14391 }
14393 /*
14394 * Queue up command to restore replica identity index marking
14395 */
14397 {
14406 /* do it after indexes and constraints */
14409 }
14411 /*
14412 * Queue up command to restore marking of index used for cluster.
14413 */
14415 {
14421 /* do it after indexes and constraints */
14424 }
14426 /*
14427 * It should be okay to use DROP_RESTRICT here, since nothing else should
14428 * be depending on these objects.
14429 */
14434 /*
14435 * The objects will get recreated during subsequent passes over the work
14436 * queue.
14437 */
14438 }
14440 /*
14441 * Parse the previously-saved definition string for a constraint, index or
14442 * statistics object against the newly-established column data type(s), and
14443 * queue up the resulting command parsetrees for execution.
14444 *
14445 * This might fail if, for example, you have a WHERE clause that uses an
14446 * operator that's not available for the new column type.
14447 */
14448 static void
14451 {
14455 Relation rel;
14457 /*
14458 * We expect that we will get only ALTER TABLE and CREATE INDEX
14459 * statements. Hence, there is no need to pass them through
14460 * parse_analyze_*() or the rewriter, but instead we need to pass them
14461 * through parse_utilcmd.c to make them ready for execution.
14462 */
14466 {
14474 cmd));
14476 {
14482 cmd,
14488 }
14493 cmd));
14494 else
14496 }
14498 /* Caller should already have acquired whatever lock we need. */
14501 /*
14502 * Attach each generated command to the proper place in the work queue.
14503 * Note this could result in creation of entirely new work-queue entries.
14504 *
14505 * Also note that we have to tweak the command subtypes, because it turns
14506 * out that re-creation of indexes and constraints has to act a bit
14507 * differently from initial creation.
14508 */
14510 {
14517 {
14524 /* keep the index's comment */
14532 }
14534 {
14539 {
14543 {
14545 Oid indoid;
14552 /* keep any comment on the index */
14561 /* recreate any comment on the constraint */
14563 AT_PASS_OLD_INDEX,
14564 oldId,
14565 rel,
14566 NIL,
14568 }
14570 {
14574 /* rewriting neither side of a FK */
14583 /*
14584 * Recreate any comment on the constraint. If we have
14585 * recreated a primary key, then transformTableConstraint
14586 * has added an unnamed not-null constraint here; skip
14587 * this in that case.
14588 */
14591 AT_PASS_OLD_CONSTR,
14592 oldId,
14593 rel,
14594 NIL,
14596 else
14598 }
14599 else
14602 }
14603 }
14605 {
14609 {
14618 /* recreate any comment on the constraint */
14620 AT_PASS_OLD_CONSTR,
14621 oldId,
14622 NULL,
14625 }
14626 else
14629 }
14631 {
14635 /* keep the statistics object's comment */
14643 }
14644 else
14647 }
14650 }
14652 /*
14653 * Subroutine for ATPostAlterTypeParse() to recreate any existing comment
14654 * for a table or domain constraint that is being rebuilt.
14655 *
14656 * objid is the OID of the constraint.
14657 * Pass "rel" for a table constraint, or "domname" (domain's qualified name
14658 * as a string list) for a domain constraint.
14659 * (We could dig that info, as well as the conname, out of the pg_constraint
14660 * entry; but callers already have them so might as well pass them.)
14661 */
14662 static void
14666 {
14671 /* Look for comment for object wanted, and leave if none */
14676 /* Build CommentStmt node, copying all input data for safety */
14679 {
14685 }
14686 else
14687 {
14692 }
14695 /* Append it to list of commands */
14700 }
14702 /*
14703 * Subroutine for ATPostAlterTypeParse(). Calls out to CheckIndexCompatible()
14704 * for the real analysis, then mutates the IndexStmt based on that verdict.
14705 */
14706 static void
14708 {
14714 {
14717 /* If it's a partitioned index, there is no storage to share. */
14719 {
14723 }
14725 }
14726 }
14728 /*
14729 * Subroutine for ATPostAlterTypeParse().
14730 *
14731 * Stash the old P-F equality operator into the Constraint node, for possible
14732 * use by ATAddForeignKeyConstraint() in determining whether revalidation of
14733 * this constraint can be skipped.
14734 */
14735 static void
14737 {
14738 HeapTuple tup;
14739 Datum adatum;
14753 Anum_pg_constraint_conpfeqop);
14756 /* test follows the one in ri_FetchConstraintInfo() */
14763 /* stash a List of the operator Oids in our Constraint node */
14768 }
14770 /*
14771 * ALTER COLUMN .. OPTIONS ( ... )
14772 *
14773 * Returns the address of the modified column
14774 */
14775 static ObjectAddress
14779 LOCKMODE lockmode)
14780 {
14781 Relation ftrel;
14782 Relation attrel;
14785 HeapTuple tuple;
14786 HeapTuple newtuple;
14791 Datum datum;
14792 Form_pg_foreign_table fttableform;
14793 Form_pg_attribute atttableform;
14794 AttrNumber attnum;
14795 ObjectAddress address;
14800 /* First, determine FDW validator associated to the foreign table. */
14823 /* Prevent them from altering a system attribute */
14832 /* Initialize buffers for new tuple values */
14837 /* Extract the current options */
14839 tuple,
14840 Anum_pg_attribute_attfdwoptions,
14845 /* Transform the options */
14847 datum,
14848 options,
14853 else
14858 /* Everything looks good - update the tuple */
14878 }
14880 /*
14881 * ALTER TABLE OWNER
14882 *
14883 * recursing is true if we are recursing from a table to its indexes,
14884 * sequences, or toast table. We don't allow the ownership of those things to
14885 * be changed separately from the parent table. Also, we can skip permission
14886 * checks (this is necessary not just an optimization, else we'd fail to
14887 * handle toast tables properly).
14888 *
14889 * recursing is also true if ALTER TYPE OWNER is calling us to fix up a
14890 * free-standing composite type.
14891 */
14892 void
14894 {
14895 Relation target_rel;
14896 Relation class_rel;
14897 HeapTuple tuple;
14898 Form_pg_class tuple_class;
14900 /*
14901 * Get exclusive lock till end of transaction on the target table. Use
14902 * relation_open so that we can work on indexes and sequences.
14903 */
14906 /* Get its pg_class tuple, too */
14914 /* Can we change the ownership of this tuple? */
14916 {
14922 /* ok to change owner */
14926 {
14927 /*
14928 * Because ALTER INDEX OWNER used to be allowed, and in fact
14929 * is generated by old versions of pg_dump, we give a warning
14930 * and do nothing rather than erroring out. Also, to avoid
14931 * unnecessary chatter while restoring those old dumps, say
14932 * nothing at all if the command would be a no-op anyway.
14933 */
14940 /* quick hack to exit via the no-op path */
14942 }
14956 {
14957 /* if it's an owned sequence, disallow changing it by itself */
14958 Oid tableId;
14959 int32 colId;
14970 }
14979 /* translator: %s is an SQL ALTER command */
14986 /* FALL THRU */
14993 }
14995 /*
14996 * If the new owner is the same as the existing owner, consider the
14997 * command to have succeeded. This is for dump restoration purposes.
14998 */
15000 {
15005 Datum aclDatum;
15007 HeapTuple newtuple;
15009 /* skip permission checks when recursing to index or toast table */
15011 {
15012 /* Superusers can always do it */
15014 {
15016 AclResult aclresult;
15018 /* Otherwise, must be owner of the existing object */
15023 /* Must be able to become new owner */
15026 /* New owner must have CREATE privilege on namespace */
15028 ACL_CREATE);
15032 }
15033 }
15041 /*
15042 * Determine the modified ACL for the new owner. This is only
15043 * necessary when the ACL is non-null.
15044 */
15046 Anum_pg_class_relacl,
15049 {
15054 }
15056 newtuple = heap_modify_tuple(tuple, RelationGetDescr(class_rel), repl_val, repl_null, repl_repl);
15062 /*
15063 * We must similarly update any per-column ACLs to reflect the new
15064 * owner; for neatness reasons that's split out as a subroutine.
15065 */
15068 newOwnerId);
15070 /*
15071 * Update owner dependency reference, if any. A composite type has
15072 * none, because it's tracked for the pg_type entry instead of here;
15073 * indexes and TOAST tables don't have their own entries either.
15074 */
15080 newOwnerId);
15082 /*
15083 * Also change the ownership of the table's row type, if it has one
15084 */
15088 /*
15089 * If we are operating on a table or materialized view, also change
15090 * the ownership of any indexes and sequences that belong to the
15091 * relation, as well as its toast table (if it has one).
15092 */
15097 {
15101 /* Find all the indexes belonging to this relation */
15104 /* For each index, recursively change its ownership */
15109 }
15111 /* If it has a toast table, recurse to change its ownership */
15116 /* If it has dependent sequences, recurse to change them too */
15118 }
15125 }
15127 /*
15128 * change_owner_fix_column_acls
15129 *
15130 * Helper function for ATExecChangeOwner. Scan the columns of the table
15131 * and fix any non-null column ACLs to reflect the new owner.
15132 */
15133 static void
15135 {
15136 Relation attRelation;
15137 SysScanDesc scan;
15139 HeapTuple attributeTuple;
15143 Anum_pg_attribute_attrelid,
15149 {
15155 Datum aclDatum;
15157 HeapTuple newtuple;
15159 /* Ignore dropped columns */
15164 Anum_pg_attribute_attacl,
15167 /* Null ACLs do not require changes */
15186 }
15189 }
15191 /*
15192 * change_owner_recurse_to_sequences
15193 *
15194 * Helper function for ATExecChangeOwner. Examines pg_depend searching
15195 * for sequences that are dependent on serial columns, and changes their
15196 * ownership.
15197 */
15198 static void
15200 {
15201 Relation depRel;
15202 SysScanDesc scan;
15204 HeapTuple tup;
15206 /*
15207 * SERIAL sequences are those having an auto dependency on one of the
15208 * table's columns (we don't care *which* column, exactly).
15209 */
15213 Anum_pg_depend_refclassid,
15217 Anum_pg_depend_refobjid,
15220 /* we leave refobjsubid unspecified */
15226 {
15228 Relation seqRel;
15230 /* skip dependencies other than auto dependencies on columns */
15237 /* Use relation_open just in case it's an index */
15240 /* skip non-sequence relations */
15242 {
15243 /* No need to keep the lock */
15246 }
15248 /* We don't need to close the sequence while we alter it. */
15251 /* Now we can close it. Keep the lock till end of transaction. */
15253 }
15258 }
15260 /*
15261 * ALTER TABLE CLUSTER ON
15262 *
15263 * The only thing we have to do is to change the indisclustered bits.
15264 *
15265 * Return the address of the new clustering index.
15266 */
15267 static ObjectAddress
15269 {
15270 Oid indexOid;
15271 ObjectAddress address;
15281 /* Check index is valid to cluster on */
15284 /* And do the work */
15291 }
15293 /*
15294 * ALTER TABLE SET WITHOUT CLUSTER
15295 *
15296 * We have to find any indexes on the table that have indisclustered bit
15297 * set and turn it off.
15298 */
15299 static void
15301 {
15303 }
15305 /*
15306 * Preparation phase for SET ACCESS METHOD
15307 *
15308 * Check that the access method exists and determine whether a change is
15309 * actually needed.
15310 */
15311 static void
15313 {
15314 Oid amoid;
15316 /*
15317 * Look up the access method name and check that it differs from the
15318 * table's current AM. If DEFAULT was specified for a partitioned table
15319 * (amname is NULL), set it to InvalidOid to reset the catalogued AM.
15320 */
15325 else
15328 /* if it's a match, phase 3 doesn't need to do anything */
15332 /* Save info for Phase 3 to do the real work */
15336 }
15338 /*
15339 * Special handling of ALTER TABLE SET ACCESS METHOD for relations with no
15340 * storage that have an interest in preserving AM.
15341 *
15342 * Since these have no storage, setting the access method is a catalog only
15343 * operation.
15344 */
15345 static void
15347 {
15348 Relation pg_class;
15349 Oid oldAccessMethodId;
15350 HeapTuple tuple;
15351 Form_pg_class rd_rel;
15354 /*
15355 * Shouldn't be called on relations having storage; these are processed in
15356 * phase 3.
15357 */
15360 /* Get a modifiable copy of the relation's pg_class row. */
15368 /* Update the pg_class row. */
15372 /* Leave if no update required */
15374 {
15378 }
15382 /*
15383 * Update the dependency on the new access method. No dependency is added
15384 * if the new access method is InvalidOid (default case). Be very careful
15385 * that this has to compare the previous value stored in pg_class with the
15386 * new one.
15387 */
15389 {
15390 ObjectAddress relobj,
15391 referenced;
15393 /*
15394 * New access method is defined and there was no dependency
15395 * previously, so record a new one.
15396 */
15400 }
15403 {
15404 /*
15405 * There was an access method defined, and no new one, so just remove
15406 * the existing dependency.
15407 */
15409 AccessMethodRelationId,
15410 DEPENDENCY_NORMAL);
15411 }
15412 else
15413 {
15417 /* Both are valid, so update the dependency */
15419 AccessMethodRelationId,
15421 }
15423 /* make the relam and dependency changes visible */
15430 }
15432 /*
15433 * ALTER TABLE SET TABLESPACE
15434 */
15435 static void
15436 ATPrepSetTableSpace(AlteredTableInfo *tab, Relation rel, const char *tablespacename, LOCKMODE lockmode)
15437 {
15438 Oid tablespaceId;
15440 /* Check that the tablespace exists */
15443 /* Check permissions except when moving to database's default */
15445 {
15446 AclResult aclresult;
15451 }
15453 /* Save info for Phase 3 to do the real work */
15460 }
15462 /*
15463 * Set, reset, or replace reloptions.
15464 */
15465 static void
15467 LOCKMODE lockmode)
15468 {
15469 Oid relid;
15470 Relation pgclass;
15471 HeapTuple tuple;
15472 HeapTuple newtuple;
15473 Datum datum;
15475 Datum newOptions;
15486 /* Fetch heap tuple */
15493 {
15494 /*
15495 * If we're supposed to replace the reloptions list, we just pretend
15496 * there were none before.
15497 */
15500 }
15501 else
15502 {
15503 /* Get the old reloptions */
15506 }
15508 /* Generate new proposed reloptions (text array) */
15513 /* Validate */
15515 {
15538 }
15540 /* Special-case validation of view options */
15542 {
15549 {
15554 }
15556 /*
15557 * If the check option is specified, look to see if the view is
15558 * actually auto-updatable or not.
15559 */
15561 {
15570 }
15571 }
15573 /*
15574 * All we need do here is update the pg_class row; the new options will be
15575 * propagated into relcaches during post-commit cache inval.
15576 */
15583 else
15600 /* repeat the whole exercise for the toast table, if there's one */
15602 {
15603 Relation toastrel;
15608 /* Fetch heap tuple */
15614 {
15615 /*
15616 * If we're supposed to replace the reloptions list, we just
15617 * pretend there were none before.
15618 */
15621 }
15622 else
15623 {
15624 /* Get the old reloptions */
15627 }
15641 else
15660 }
15663 }
15665 /*
15666 * Execute ALTER TABLE SET TABLESPACE for cases where there is no tuple
15667 * rewriting to be done, so we just want to copy the data as fast as possible.
15668 */
15669 static void
15671 {
15672 Relation rel;
15673 Oid reltoastrelid;
15674 RelFileNumber newrelfilenumber;
15675 RelFileLocator newrlocator;
15679 /*
15680 * Need lock here in case we are recursing to toast table or index
15681 */
15684 /* Check first if relation can be moved to new tablespace */
15686 {
15691 }
15694 /* Fetch the list of indexes on toast relation if necessary */
15696 {
15701 }
15703 /*
15704 * Relfilenumbers are not unique in databases across tablespaces, so we
15705 * need to allocate a new one in the new tablespace.
15706 */
15710 /* Open old and new relation */
15715 /* hand off to AM to actually create new rel storage and copy the data */
15717 {
15719 }
15720 else
15721 {
15724 }
15726 /*
15727 * Update the pg_class row.
15728 *
15729 * NB: This wouldn't work if ATExecSetTableSpace() were allowed to be
15730 * executed on pg_class or its indexes (the above copy wouldn't contain
15731 * the updated pg_class entry), but that's forbidden with
15732 * CheckRelationTableSpaceMove().
15733 */
15742 /* Make sure the reltablespace change is visible */
15745 /* Move associated toast relation and/or indexes, too */
15751 /* Clean up */
15753 }
15755 /*
15756 * Special handling of ALTER TABLE SET TABLESPACE for relations with no
15757 * storage that have an interest in preserving tablespace.
15758 *
15759 * Since these have no storage the tablespace can be updated with a simple
15760 * metadata only operation to update the tablespace.
15761 */
15762 static void
15764 {
15765 /*
15766 * Shouldn't be called on relations having storage; these are processed in
15767 * phase 3.
15768 */
15771 /* check if relation can be moved to its new tablespace */
15773 {
15778 }
15780 /* Update can be done, so change reltablespace */
15785 /* Make sure the reltablespace change is visible */
15787 }
15789 /*
15790 * Alter Table ALL ... SET TABLESPACE
15791 *
15792 * Allows a user to move all objects of some type in a given tablespace in the
15793 * current database to another tablespace. Objects can be chosen based on the
15794 * owner of the object also, to allow users to move only their objects.
15795 * The user must have CREATE rights on the new tablespace, as usual. The main
15796 * permissions handling is done by the lower-level table move function.
15797 *
15798 * All to-be-moved objects are locked first. If NOWAIT is specified and the
15799 * lock can't be acquired then we ereport(ERROR).
15800 */
15801 Oid
15803 {
15807 Relation rel;
15808 TableScanDesc scan;
15809 HeapTuple tuple;
15810 Oid orig_tablespaceoid;
15811 Oid new_tablespaceoid;
15814 /* Ensure we were not asked to move something we can't */
15821 /* Get the orig and new tablespace OIDs */
15825 /* Can't move shared relations in to or out of pg_global */
15826 /* This is also checked by ATExecSetTableSpace, but nice to stop earlier */
15833 /*
15834 * Must have CREATE rights on the new tablespace, unless it is the
15835 * database default tablespace (which all users implicitly have CREATE
15836 * rights on).
15837 */
15839 {
15840 AclResult aclresult;
15843 ACL_CREATE);
15847 }
15849 /*
15850 * Now that the checks are done, check if we should set either to
15851 * InvalidOid because it is our database's default tablespace.
15852 */
15859 /* no-op */
15863 /*
15864 * Walk the list of objects in the tablespace and move them. This will
15865 * only find objects in our database, of course.
15866 */
15868 Anum_pg_class_reltablespace,
15875 {
15879 /*
15880 * Do not move objects in pg_catalog as part of this, if an admin
15881 * really wishes to do so, they can issue the individual ALTER
15882 * commands directly.
15883 *
15884 * Also, explicitly avoid any shared tables, temp tables, or TOAST
15885 * (TOAST will be moved with the main table).
15886 */
15893 /* Only move the object type requested */
15904 /* Check if we are only moving objects owned by certain roles */
15908 /*
15909 * Handle permissions-checking here since we are locking the tables
15910 * and also to avoid doing a bunch of work only to fail part-way. Note
15911 * that permissions will also be checked by AlterTableInternal().
15912 *
15913 * Caller must be considered an owner on the table to move it.
15914 */
15926 else
15929 /* Add to our list of objects to move */
15931 }
15943 /* Everything is locked, loop through and move all of the relations. */
15945 {
15955 /* OID is set by AlterTableInternal */
15958 }
15961 }
15963 static void
15965 {
15966 SMgrRelation dstrel;
15968 /*
15969 * Since we copy the file directly without looking at the shared buffers,
15970 * we'd better first flush out any pages of the source relation that are
15971 * in shared buffers. We assume no new changes will be made while we are
15972 * holding exclusive lock on the rel.
15973 */
15976 /*
15977 * Create and copy all forks of the relation, and schedule unlinking of
15978 * old physical files.
15979 *
15980 * NOTE: any conflict in relfilenumber value will be caught in
15981 * RelationCreateStorage().
15982 */
15985 /* copy main fork */
15989 /* copy those extra forks that exist */
15992 {
15994 {
15997 /*
15998 * WAL log creation if the relation is persistent, or this is the
15999 * init fork of an unlogged relation.
16000 */
16007 }
16008 }
16010 /* drop old relation, and close new one */
16013 }
16015 /*
16016 * ALTER TABLE ENABLE/DISABLE TRIGGER
16017 *
16018 * We just pass this off to trigger.c.
16019 */
16020 static void
16023 LOCKMODE lockmode)
16024 {
16027 lockmode);
16031 }
16033 /*
16034 * ALTER TABLE ENABLE/DISABLE RULE
16035 *
16036 * We just pass this off to rewriteDefine.c.
16037 */
16038 static void
16041 {
16046 }
16048 /*
16049 * ALTER TABLE INHERIT
16050 *
16051 * Add a parent to the child's parents. This verifies that all the columns and
16052 * check constraints of the parent appear in the child and that they have the
16053 * same data types and expressions.
16054 */
16055 static void
16057 {
16072 }
16074 /*
16075 * Return the address of the new parent relation.
16076 */
16077 static ObjectAddress
16079 {
16080 Relation parent_rel;
16082 ObjectAddress address;
16085 /*
16086 * A self-exclusive lock is needed here. See the similar case in
16087 * MergeAttributes() for a full explanation.
16088 */
16091 /*
16092 * Must be owner of both parent and child -- child was checked by
16093 * ATSimplePermissions call in ATPrepCmd
16094 */
16098 /* Permanent rels cannot inherit from temporary ones */
16106 /* If parent rel is temp, it must belong to this session */
16113 /* Ditto for the child */
16120 /* Prevent partitioned tables from becoming inheritance parents */
16127 /* Likewise for partitions */
16133 /*
16134 * Prevent circularity by seeing if proposed parent inherits from child.
16135 * (In particular, this disallows making a rel inherit from itself.)
16136 *
16137 * This is not completely bulletproof because of race conditions: in
16138 * multi-level inheritance trees, someone else could concurrently be
16139 * making another inheritance link that closes the loop but does not join
16140 * either of the rels we have locked. Preventing that seems to require
16141 * exclusive locks on the entire inheritance tree, which is a cure worse
16142 * than the disease. find_all_inheritors() will cope with circularity
16143 * anyway, so don't sweat it too much.
16144 *
16145 * We use weakest lock we can on child's children, namely AccessShareLock.
16146 */
16158 /*
16159 * If child_rel has row-level triggers with transition tables, we
16160 * currently don't allow it to become an inheritance child. See also
16161 * prohibitions in ATExecAttachPartition() and CreateTrigger().
16162 */
16169 errdetail("ROW triggers with transition tables are not supported in inheritance hierarchies.")));
16171 /* OK to create inheritance */
16177 /* keep our lock on the parent relation until commit */
16181 }
16183 /*
16184 * CreateInheritance
16185 * Catalog manipulation portion of creating inheritance between a child
16186 * table and a parent table.
16187 *
16188 * Common to ATExecAddInherit() and ATExecAttachPartition().
16189 */
16190 static void
16192 {
16193 Relation catalogRelation;
16194 SysScanDesc scan;
16195 ScanKeyData key;
16196 HeapTuple inheritsTuple;
16197 int32 inhseqno;
16199 /* Note: get RowExclusiveLock because we will write pg_inherits below. */
16202 /*
16203 * Check for duplicates in the list of parents, and determine the highest
16204 * inhseqno already present; we'll use the next one for the new parent.
16205 * Also, if proposed child is a partition, it cannot already be
16206 * inheriting.
16207 *
16208 * Note: we do not reject the case where the child already inherits from
16209 * the parent indirectly; CREATE TABLE doesn't reject comparable cases.
16210 */
16212 Anum_pg_inherits_inhrelid,
16218 /* inhseqno sequences start at 1 */
16221 {
16232 }
16235 /* Match up the columns and bump attinhcount as needed */
16238 /* Match up the constraints and bump coninhcount as needed */
16241 /*
16242 * OK, it looks valid. Make the catalog entries that show inheritance.
16243 */
16247 catalogRelation,
16249 RELKIND_PARTITIONED_TABLE);
16251 /* Now we're done with pg_inherits */
16253 }
16255 /*
16256 * Obtain the source-text form of the constraint expression for a check
16257 * constraint, given its pg_constraint tuple
16258 */
16261 {
16262 Form_pg_constraint con;
16264 Datum attr;
16265 Datum expr;
16275 }
16277 /*
16278 * Determine whether two check constraints are functionally equivalent
16279 *
16280 * The test we apply is to see whether they reverse-compile to the same
16281 * source string. This insulates us from issues like whether attributes
16282 * have the same physical column numbers in parent and child relations.
16283 *
16284 * Note that we ignore enforceability as there are cases where constraints
16285 * with differing enforceability are allowed.
16286 */
16287 static bool
16289 {
16298 else
16300 }
16302 /*
16303 * Check columns in child table match up with columns in parent, and increment
16304 * their attinhcount.
16305 *
16306 * Called by CreateInheritance
16307 *
16308 * Currently all parent columns must be found in child. Missing columns are an
16309 * error. One day we might consider creating new columns like CREATE TABLE
16310 * does. However, that is widely unpopular --- in the common use case of
16311 * partitioned tables it's a foot-gun.
16312 *
16313 * The data type must match exactly. If the parent column is NOT NULL then
16314 * the child must be as well. Defaults are not compared, however.
16315 */
16316 static void
16318 {
16319 Relation attrrel;
16320 TupleDesc parent_desc;
16326 {
16329 HeapTuple tuple;
16331 /* Ignore dropped columns in the parent. */
16335 /* Find same column in child (matching on column name). */
16338 {
16354 /*
16355 * If the parent has a not-null constraint that's not NO INHERIT,
16356 * make sure the child has one too.
16357 *
16358 * Other constraints are checked elsewhere.
16359 */
16361 {
16362 HeapTuple contup;
16372 }
16374 /*
16375 * Child column must be generated if and only if parent column is.
16376 */
16386 /*
16387 * Regular inheritance children are independent enough not to
16388 * inherit identity columns. But partitions are integral part of
16389 * a partitioned table and inherit identity column.
16390 */
16394 /*
16395 * OK, bump the child column's inheritance count. (If we fail
16396 * later on, this change will just roll back.)
16397 */
16404 /*
16405 * In case of partitions, we must enforce that value of attislocal
16406 * is same in all partitions. (Note: there are only inherited
16407 * attributes in partitions)
16408 */
16410 {
16413 }
16417 }
16418 else
16419 {
16423 }
16424 }
16427 }
16429 /*
16430 * Check constraints in child table match up with constraints in parent,
16431 * and increment their coninhcount.
16432 *
16433 * Constraints that are marked ONLY in the parent are ignored.
16434 *
16435 * Called by CreateInheritance
16436 *
16437 * Currently all constraints in parent must be present in the child. One day we
16438 * may consider adding new constraints like CREATE TABLE does.
16439 *
16440 * XXX This is O(N^2) which may be an issue with tables with hundreds of
16441 * constraints. As long as tables have more like 10 constraints it shouldn't be
16442 * a problem though. Even 100 constraints ought not be the end of the world.
16443 *
16444 * XXX See MergeWithExistingConstraint too if you change this code.
16445 */
16446 static void
16448 {
16449 Relation constraintrel;
16450 SysScanDesc parent_scan;
16451 ScanKeyData parent_key;
16452 HeapTuple parent_tuple;
16458 /* Outer loop scans through the parent's constraint definitions */
16460 Anum_pg_constraint_conrelid,
16471 {
16473 SysScanDesc child_scan;
16474 ScanKeyData child_key;
16475 HeapTuple child_tuple;
16476 AttrNumber parent_attno;
16483 /* if the parent's constraint is marked NO INHERIT, it's not inherited */
16489 else
16492 /* Search for a child constraint matching this one */
16494 Anum_pg_constraint_conrelid,
16501 {
16503 HeapTuple child_copy;
16508 /*
16509 * CHECK constraint are matched by constraint name, NOT NULL ones
16510 * by attribute number.
16511 */
16513 {
16517 }
16519 {
16520 Form_pg_attribute parent_attr;
16521 Form_pg_attribute child_attr;
16522 AttrNumber child_attno;
16530 /* there shouldn't be constraints on dropped columns */
16533 }
16542 /*
16543 * If the child constraint is "no inherit" then cannot merge
16544 */
16551 /*
16552 * If the child constraint is "not valid" then cannot merge with a
16553 * valid parent constraint
16554 */
16562 /*
16563 * A non-enforced child constraint cannot be merged with an
16564 * enforced parent constraint. However, the reverse is allowed,
16565 * where the child constraint is enforced.
16566 */
16573 /*
16574 * OK, bump the child constraint's inheritance count. (If we fail
16575 * later on, this change will just roll back.)
16576 */
16586 /*
16587 * In case of partitions, an inherited constraint must be
16588 * inherited only once since it cannot have multiple parents and
16589 * it is never considered local.
16590 */
16592 {
16595 }
16602 }
16607 {
16621 }
16622 }
16626 }
16628 /*
16629 * ALTER TABLE NO INHERIT
16630 *
16631 * Return value is the address of the relation that is no longer parent.
16632 */
16633 static ObjectAddress
16635 {
16636 ObjectAddress address;
16637 Relation parent_rel;
16644 /*
16645 * AccessShareLock on the parent is probably enough, seeing that DROP
16646 * TABLE doesn't lock parent tables at all. We need some lock since we'll
16647 * be inspecting the parent's schema.
16648 */
16651 /*
16652 * We don't bother to check ownership of the parent table --- ownership of
16653 * the child is presumed enough rights.
16654 */
16656 /* Off to RemoveInheritance() where most of the work happens */
16662 /* keep our lock on the parent relation until commit */
16666 }
16668 /*
16669 * MarkInheritDetached
16670 *
16671 * Set inhdetachpending for a partition, for ATExecDetachPartition
16672 * in concurrent mode. While at it, verify that no other partition is
16673 * already pending detach.
16674 */
16675 static void
16677 {
16678 Relation catalogRelation;
16679 SysScanDesc scan;
16680 ScanKeyData key;
16681 HeapTuple inheritsTuple;
16686 /*
16687 * Find pg_inherits entries by inhparent. (We need to scan them all in
16688 * order to verify that no other partition is pending detach.)
16689 */
16692 Anum_pg_inherits_inhparent,
16699 {
16700 Form_pg_inherits inhForm;
16710 errhint("Use ALTER TABLE ... DETACH PARTITION ... FINALIZE to complete the pending detach operation."));
16713 {
16714 HeapTuple newtup;
16721 newtup);
16724 /* keep looking, to ensure we catch others pending detach */
16725 }
16726 }
16728 /* Done */
16738 }
16740 /*
16741 * RemoveInheritance
16742 *
16743 * Drop a parent from the child's parents. This just adjusts the attinhcount
16744 * and attislocal of the columns and removes the pg_inherit and pg_depend
16745 * entries. expect_detached is passed down to DeleteInheritsTuple, q.v..
16746 *
16747 * If attinhcount goes to 0 then attislocal gets set to true. If it goes back
16748 * up attislocal stays true, which means if a child is ever removed from a
16749 * parent then its columns will never be automatically dropped which may
16750 * surprise. But at least we'll never surprise by dropping columns someone
16751 * isn't expecting to be dropped which would actually mean data loss.
16752 *
16753 * coninhcount and conislocal for inherited constraints are adjusted in
16754 * exactly the same way.
16755 *
16756 * Common to ATExecDropInherit() and ATExecDetachPartition().
16757 */
16758 static void
16760 {
16761 Relation catalogRelation;
16762 SysScanDesc scan;
16764 HeapTuple attributeTuple,
16765 constraintTuple;
16776 expect_detached,
16779 {
16786 else
16792 }
16794 /*
16795 * Search through child columns looking for ones matching parent rel
16796 */
16799 Anum_pg_attribute_attrelid,
16805 {
16808 /* Ignore if dropped or not inherited */
16816 {
16817 /* Decrement inhcount and possibly set islocal to true */
16827 }
16828 }
16832 /*
16833 * Likewise, find inherited check and not-null constraints and disinherit
16834 * them. To do this, we first need a list of the names of the parent's
16835 * check constraints. (We cheat a bit by only checking for name matches,
16836 * assuming that the expressions will match.)
16837 *
16838 * For NOT NULL columns, we store column numbers to match, mapping them in
16839 * to the child rel's attribute numbers.
16840 */
16847 Anum_pg_constraint_conrelid,
16857 {
16866 {
16870 }
16871 }
16875 /* Now scan the child's constraints to find matches */
16877 Anum_pg_constraint_conrelid,
16884 {
16888 /*
16889 * Match CHECK constraints by name, not-null constraints by column
16890 * number, and ignore all others.
16891 */
16893 {
16895 {
16898 {
16902 }
16903 }
16904 }
16906 {
16910 {
16912 {
16916 }
16917 }
16918 }
16919 else
16923 {
16924 /* Decrement inhcount and possibly set islocal to true */
16938 }
16939 }
16941 /* We should have matched all constraints */
16951 RelationRelationId,
16955 /*
16956 * Post alter hook of this inherits. Since object_access_hook doesn't take
16957 * multiple object identifiers, we relay oid of parent relation using
16958 * auxiliary_id argument.
16959 */
16963 }
16965 /*
16966 * Drop the dependency created by StoreCatalogInheritance1 (CREATE TABLE
16967 * INHERITS/ALTER TABLE INHERIT -- refclassid will be RelationRelationId) or
16968 * heap_create_with_catalog (CREATE TABLE OF/ALTER TABLE OF -- refclassid will
16969 * be TypeRelationId). There's no convenient way to do this, so go trawling
16970 * through pg_depend.
16971 */
16972 static void
16974 DependencyType deptype)
16975 {
16976 Relation catalogRelation;
16977 SysScanDesc scan;
16979 HeapTuple depTuple;
16984 Anum_pg_depend_classid,
16988 Anum_pg_depend_objid,
16992 Anum_pg_depend_objsubid,
17000 {
17008 }
17012 }
17014 /*
17015 * ALTER TABLE OF
17016 *
17017 * Attach a table to a composite type, as though it had been created with CREATE
17018 * TABLE OF. All attname, atttypid, atttypmod and attcollation must match. The
17019 * subject table must not have inheritance parents. These restrictions ensure
17020 * that you cannot create a configuration impossible with CREATE TABLE OF alone.
17021 *
17022 * The address of the type is returned.
17023 */
17024 static ObjectAddress
17026 {
17028 Type typetuple;
17029 Form_pg_type typeform;
17031 Relation inheritsRelation,
17032 relationRelation;
17033 SysScanDesc scan;
17034 ScanKeyData key;
17035 AttrNumber table_attno,
17036 type_attno;
17037 TupleDesc typeTupleDesc,
17038 tableTupleDesc;
17039 ObjectAddress tableobj,
17040 typeobj;
17041 HeapTuple classtuple;
17043 /* Validate the type. */
17049 /* Fail if the table has any inheritance parents. */
17052 Anum_pg_inherits_inhrelid,
17064 /*
17065 * Check the tuple descriptors for compatibility. Unlike inheritance, we
17066 * require that the order also match. However, attnotnull need not match.
17067 */
17072 {
17073 Form_pg_attribute type_attr,
17074 table_attr;
17078 /* Get the next non-dropped type attribute. */
17084 /* Get the next non-dropped table attribute. */
17085 do
17086 {
17091 type_attname)));
17093 table_attno++;
17097 /* Compare name. */
17104 /* Compare type. */
17112 }
17115 /* Any remaining columns at the end of the table had better be dropped. */
17117 {
17126 }
17128 /* If the table was already typed, drop the existing dependency. */
17131 DEPENDENCY_NORMAL);
17133 /* Record a dependency on the new type. */
17142 /* Update pg_class.reloftype */
17158 }
17160 /*
17161 * ALTER TABLE NOT OF
17162 *
17163 * Detach a typed table from its originating type. Just clear reloftype and
17164 * remove the dependency.
17165 */
17166 static void
17168 {
17170 Relation relationRelation;
17171 HeapTuple tuple;
17179 /*
17180 * We don't bother to check ownership of the type --- ownership of the
17181 * table is presumed enough rights. No lock required on the type, either.
17182 */
17185 DEPENDENCY_NORMAL);
17187 /* Clear pg_class.reloftype */
17199 }
17201 /*
17202 * relation_mark_replica_identity: Update a table's replica identity
17203 *
17204 * Iff ri_type = REPLICA_IDENTITY_INDEX, indexOid must be the Oid of a suitable
17205 * index. Otherwise, it must be InvalidOid.
17206 *
17207 * Caller had better hold an exclusive lock on the relation, as the results
17208 * of running two of these concurrently wouldn't be pretty.
17209 */
17210 static void
17213 {
17214 Relation pg_index;
17215 Relation pg_class;
17216 HeapTuple pg_class_tuple;
17217 HeapTuple pg_index_tuple;
17218 Form_pg_class pg_class_form;
17219 Form_pg_index pg_index_form;
17222 /*
17223 * Check whether relreplident has changed, and update it if so.
17224 */
17233 {
17236 }
17240 /*
17241 * Update the per-index indisreplident flags correctly.
17242 */
17245 {
17256 {
17257 /* Set the bit if not already set. */
17259 {
17262 }
17263 }
17264 else
17265 {
17266 /* Unset the bit if set. */
17268 {
17271 }
17272 }
17275 {
17280 /*
17281 * Invalidate the relcache for the table, so that after we commit
17282 * all sessions will refresh the table's replica identity index
17283 * before attempting any UPDATE or DELETE on the table. (If we
17284 * changed the table's pg_class row above, then a relcache inval
17285 * is already queued due to that; but we might not have.)
17286 */
17288 }
17290 }
17293 }
17295 /*
17296 * ALTER TABLE <name> REPLICA IDENTITY ...
17297 */
17298 static void
17300 {
17301 Oid indexOid;
17302 Relation indexRel;
17306 {
17309 }
17311 {
17314 }
17316 {
17319 }
17321 {
17323 }
17324 else
17327 /* Check that the index exists */
17337 /* Check that the index is on the relation we're altering. */
17346 /*
17347 * The AM must support uniqueness, and the index must in fact be unique.
17348 * If we have a WITHOUT OVERLAPS constraint (identified by uniqueness +
17349 * exclusion), we can use that too.
17350 */
17358 /* Deferred indexes are not guaranteed to be always unique. */
17364 /* Expression indexes aren't supported. */
17370 /* Predicate indexes aren't supported. */
17377 /* Check index for nullable columns. */
17379 {
17381 Form_pg_attribute attr;
17383 /*
17384 * Reject any other system columns. (Going forward, we'll disallow
17385 * indexes containing such columns in the first place, but they might
17386 * exist in older branches.)
17387 */
17391 errmsg("index \"%s\" cannot be used as replica identity because column %d is a system column",
17401 }
17403 /* This index is suitable for use as a replica identity. Mark it. */
17407 }
17409 /*
17410 * ALTER TABLE ENABLE/DISABLE ROW LEVEL SECURITY
17411 */
17412 static void
17414 {
17415 Relation pg_class;
17416 Oid relid;
17417 HeapTuple tuple;
17421 /* Pull the record for this relation and update it */
17437 }
17439 /*
17440 * ALTER TABLE FORCE/NO FORCE ROW LEVEL SECURITY
17441 */
17442 static void
17444 {
17445 Relation pg_class;
17446 Oid relid;
17447 HeapTuple tuple;
17466 }
17468 /*
17469 * ALTER FOREIGN TABLE <name> OPTIONS (...)
17470 */
17471 static void
17473 {
17474 Relation ftrel;
17477 HeapTuple tuple;
17482 Datum datum;
17483 Form_pg_foreign_table tableform;
17505 /* Extract the current options */
17507 tuple,
17508 Anum_pg_foreign_table_ftoptions,
17513 /* Transform the options */
17515 datum,
17516 options,
17521 else
17526 /* Everything looks good - update the tuple */
17533 /*
17534 * Invalidate relcache so that all sessions will refresh any cached plans
17535 * that might depend on the old options.
17536 */
17545 }
17547 /*
17548 * ALTER TABLE ALTER COLUMN SET COMPRESSION
17549 *
17550 * Return value is the address of the modified column
17551 */
17552 static ObjectAddress
17556 LOCKMODE lockmode)
17557 {
17558 Relation attrel;
17559 HeapTuple tuple;
17560 Form_pg_attribute atttableform;
17561 AttrNumber attnum;
17564 ObjectAddress address;
17570 /* copy the cache entry so we can scribble on it below */
17578 /* prevent them from altering a system attribute */
17586 /*
17587 * Check that column type is compressible, then get the attribute
17588 * compression method code
17589 */
17592 /* update pg_attribute entry */
17598 attnum);
17600 /*
17601 * Apply the change to indexes as well (only for simple index columns,
17602 * matching behavior of index.c ConstructTupleDescriptor()).
17603 */
17607 lockmode);
17613 /* make changes visible */
17619 }
17622 /*
17623 * Preparation phase for SET LOGGED/UNLOGGED
17624 *
17625 * This verifies that we're not trying to change a temp table. Also,
17626 * existing foreign key constraints are checked to avoid ending up with
17627 * permanent tables referencing unlogged tables.
17628 */
17629 static void
17631 {
17632 Relation pg_constraint;
17633 HeapTuple tuple;
17634 SysScanDesc scan;
17637 /*
17638 * Disallow changing status for a temp table. Also verify whether we can
17639 * get away with doing nothing; in such cases we don't need to run the
17640 * checks below, either.
17641 */
17643 {
17653 /* nothing to do */
17658 /* nothing to do */
17661 }
17663 /*
17664 * Check that the table is not part of any publication when changing to
17665 * UNLOGGED, as UNLOGGED tables can't be published.
17666 */
17675 /*
17676 * Check existing foreign key constraints to preserve the invariant that
17677 * permanent tables cannot reference unlogged ones. Self-referencing
17678 * foreign keys can safely be ignored.
17679 */
17682 /*
17683 * Scan conrelid if changing to permanent, else confrelid. This also
17684 * determines whether a useful index exists.
17685 */
17688 Anum_pg_constraint_confrelid,
17696 {
17700 {
17701 Oid foreignrelid;
17702 Relation foreignrel;
17704 /* the opposite end of what we used as scankey */
17707 /* ignore if self-referencing */
17714 {
17722 }
17723 else
17724 {
17732 }
17735 }
17736 }
17742 /* force rewrite if necessary; see comment in ATRewriteTables */
17746 else
17749 }
17751 /*
17752 * Execute ALTER TABLE SET SCHEMA
17753 */
17754 ObjectAddress
17756 {
17757 Relation rel;
17758 Oid relid;
17759 Oid oldNspOid;
17760 Oid nspOid;
17763 ObjectAddress myself;
17767 RangeVarCallbackForAlterRelation,
17768 stmt);
17771 {
17776 }
17782 /* If it's an owned sequence, disallow moving it by itself. */
17784 {
17785 Oid tableId;
17786 int32 colId;
17796 }
17798 /* Get and lock schema OID and check its permissions. */
17802 /* common checks on switching namespaces */
17814 /* close rel, but keep lock until commit */
17818 }
17820 /*
17821 * The guts of relocating a table or materialized view to another namespace:
17822 * besides moving the relation itself, its dependent objects are relocated to
17823 * the new schema.
17824 */
17825 void
17828 {
17829 Relation classRel;
17833 /* OK, modify the pg_class row and pg_depend entry */
17839 /* Fix the table's row type too, if it has one */
17845 objsMoved);
17847 /* Fix other dependent stuff */
17855 }
17857 /*
17858 * The guts of relocating a relation to another namespace: fix the pg_class
17859 * entry, and the pg_depend entry if any. Caller must already have
17860 * opened and write-locked pg_class.
17861 */
17862 void
17867 {
17868 HeapTuple classTup;
17869 Form_pg_class classForm;
17870 ObjectAddress thisobj;
17873 /* no rel lock for relkind=c so use LOCKTAG_TUPLE */
17885 /*
17886 * If the object has already been moved, don't move it again. If it's
17887 * already in the right place, don't move it, but still fire the object
17888 * access hook.
17889 */
17892 {
17895 /* check for duplicate name (more friendly than unique-index failure) */
17904 /* classTup is a copy, so OK to scribble on */
17911 /* Update dependency on schema if caller said so */
17914 relOid,
17915 NamespaceRelationId,
17916 oldNspOid,
17920 }
17921 else
17924 {
17928 }
17931 }
17933 /*
17934 * Move all indexes for the specified relation to another namespace.
17935 *
17936 * Note: we assume adequate permission checking was done by the caller,
17937 * and that the caller has a suitable lock on the owning relation.
17938 */
17939 static void
17942 {
17949 {
17951 ObjectAddress thisobj;
17957 /*
17958 * Note: currently, the index will not have its own dependency on the
17959 * namespace, so we don't need to do changeDependencyFor(). There's no
17960 * row type in pg_type, either.
17961 *
17962 * XXX this objsMoved test may be pointless -- surely we have a single
17963 * dependency link from a relation to each index?
17964 */
17966 {
17971 }
17972 }
17975 }
17977 /*
17978 * Move all identity and SERIAL-column sequences of the specified relation to another
17979 * namespace.
17980 *
17981 * Note: we assume adequate permission checking was done by the caller,
17982 * and that the caller has a suitable lock on the owning relation.
17983 */
17984 static void
17987 LOCKMODE lockmode)
17988 {
17989 Relation depRel;
17990 SysScanDesc scan;
17992 HeapTuple tup;
17994 /*
17995 * SERIAL sequences are those having an auto dependency on one of the
17996 * table's columns (we don't care *which* column, exactly).
17997 */
18001 Anum_pg_depend_refclassid,
18005 Anum_pg_depend_refobjid,
18008 /* we leave refobjsubid unspecified */
18014 {
18016 Relation seqRel;
18018 /* skip dependencies other than auto dependencies on columns */
18025 /* Use relation_open just in case it's an index */
18028 /* skip non-sequence relations */
18030 {
18031 /* No need to keep the lock */
18034 }
18036 /* Fix the pg_class and pg_depend entries */
18041 /*
18042 * Sequences used to have entries in pg_type, but no longer do. If we
18043 * ever re-instate that, we'll need to move the pg_type entry to the
18044 * new namespace, too (using AlterTypeNamespaceInternal).
18045 */
18048 /* Now we can close it. Keep the lock till end of transaction. */
18050 }
18055 }
18058 /*
18059 * This code supports
18060 * CREATE TEMP TABLE ... ON COMMIT { DROP | PRESERVE ROWS | DELETE ROWS }
18061 *
18062 * Because we only support this for TEMP tables, it's sufficient to remember
18063 * the state in a backend-local data structure.
18064 */
18066 /*
18067 * Register a newly-created relation's ON COMMIT action.
18068 */
18069 void
18071 {
18073 MemoryContext oldcxt;
18075 /*
18076 * We needn't bother registering the relation unless there is an ON COMMIT
18077 * action we need to take.
18078 */
18090 /*
18091 * We use lcons() here so that ON COMMIT actions are processed in reverse
18092 * order of registration. That might not be essential but it seems
18093 * reasonable.
18094 */
18098 }
18100 /*
18101 * Unregister any ON COMMIT action when a relation is deleted.
18102 *
18103 * Actually, we only mark the OnCommitItem entry as to be deleted after commit.
18104 */
18105 void
18107 {
18111 {
18115 {
18118 }
18119 }
18120 }
18122 /*
18123 * Perform ON COMMIT actions.
18124 *
18125 * This is invoked just before actually committing, since it's possible
18126 * to encounter errors.
18127 */
18128 void
18130 {
18136 {
18139 /* Ignore entry if already dropped in this xact */
18144 {
18147 /* Do nothing (there shouldn't be such entries, actually) */
18151 /*
18152 * If this transaction hasn't accessed any temporary
18153 * relations, we can skip truncating ON COMMIT DELETE ROWS
18154 * tables, as they must still be empty.
18155 */
18162 }
18163 }
18165 /*
18166 * Truncate relations before dropping so that all dependencies between
18167 * relations are removed after they are worked on. Doing it like this
18168 * might be a waste as it is possible that a relation being truncated will
18169 * be dropped anyway due to its parent being dropped, but this makes the
18170 * code more robust because of not having to re-check that the relation
18171 * exists at truncation time.
18172 */
18177 {
18181 {
18182 ObjectAddress object;
18191 }
18193 /*
18194 * Object deletion might involve toast table access (to clean up
18195 * toasted catalog entries), so ensure we have a valid snapshot.
18196 */
18199 /*
18200 * Since this is an automatic drop, rather than one directly initiated
18201 * by the user, we pass the PERFORM_DELETION_INTERNAL flag.
18202 */
18208 #ifdef USE_ASSERT_CHECKING
18210 /*
18211 * Note that table deletion will call remove_on_commit_action, so the
18212 * entry should get marked as deleted.
18213 */
18215 {
18222 }
18223 #endif
18224 }
18225 }
18227 /*
18228 * Post-commit or post-abort cleanup for ON COMMIT management.
18229 *
18230 * All we do here is remove no-longer-needed OnCommitItem entries.
18231 *
18232 * During commit, remove entries that were deleted during this transaction;
18233 * during abort, remove those created during this transaction.
18234 */
18235 void
18237 {
18241 {
18246 {
18247 /* cur_item must be removed */
18250 }
18251 else
18252 {
18253 /* cur_item must be preserved */
18256 }
18257 }
18258 }
18260 /*
18261 * Post-subcommit or post-subabort cleanup for ON COMMIT management.
18262 *
18263 * During subabort, we can immediately remove entries created during this
18264 * subtransaction. During subcommit, just relabel entries marked during
18265 * this subtransaction as being the parent's responsibility.
18266 */
18267 void
18269 SubTransactionId parentSubid)
18270 {
18274 {
18278 {
18279 /* cur_item must be removed */
18282 }
18283 else
18284 {
18285 /* cur_item must be preserved */
18290 }
18291 }
18292 }
18294 /*
18295 * This is intended as a callback for RangeVarGetRelidExtended(). It allows
18296 * the relation to be locked only if (1) it's a plain or partitioned table,
18297 * materialized view, or TOAST table and (2) the current user is the owner (or
18298 * the superuser) or has been granted MAINTAIN. This meets the
18299 * permission-checking needs of CLUSTER, REINDEX TABLE, and REFRESH
18300 * MATERIALIZED VIEW; we expose it here so that it can be used by all.
18301 */
18302 void
18305 {
18307 AclResult aclresult;
18309 /* Nothing to do if the relation was not found. */
18313 /*
18314 * If the relation does exist, check whether it's an index. But note that
18315 * the relation might have been dropped between the time we did the name
18316 * lookup and now. In that case, there's nothing to do.
18317 */
18327 /* Check permissions */
18333 }
18335 /*
18336 * Callback to RangeVarGetRelidExtended() for TRUNCATE processing.
18337 */
18338 static void
18341 {
18342 HeapTuple tuple;
18344 /* Nothing to do if the relation was not found. */
18356 }
18358 /*
18359 * Callback for RangeVarGetRelidExtended(). Checks that the current user is
18360 * the owner of the relation, or superuser.
18361 */
18362 void
18365 {
18366 HeapTuple tuple;
18368 /* Nothing to do if the relation was not found. */
18388 }
18390 /*
18391 * Common RangeVarGetRelid callback for rename, set schema, and alter table
18392 * processing.
18393 */
18394 static void
18397 {
18399 ObjectType reltype;
18400 HeapTuple tuple;
18401 Form_pg_class classform;
18402 AclResult aclresult;
18411 /* Must own relation. */
18415 /* No system table modifications unless explicitly allowed. */
18422 /*
18423 * Extract the specified relation type from the statement parse tree.
18424 *
18425 * Also, for ALTER .. RENAME, check permissions: the user must (still)
18426 * have CREATE rights on the containing namespace.
18427 */
18429 {
18436 }
18442 else
18443 {
18446 }
18448 /*
18449 * For compatibility with prior releases, we allow ALTER TABLE to be used
18450 * with most other types of relations (but not composite types). We allow
18451 * similar flexibility for ALTER INDEX in the case of RENAME, but not
18452 * otherwise. Otherwise, the user must select the correct form of the
18453 * command for the relation at issue.
18454 */
18481 relkind != RELKIND_PARTITIONED_INDEX
18487 /*
18488 * Don't allow ALTER TABLE on composite types. We want people to use ALTER
18489 * TYPE for that.
18490 */
18495 /* translator: %s is an SQL ALTER command */
18499 /*
18500 * Don't allow ALTER TABLE .. SET SCHEMA on relations that can't be moved
18501 * to a different schema, such as indexes and TOAST tables.
18502 */
18504 {
18516 /* translator: %s is an SQL ALTER command */
18525 }
18528 }
18530 /*
18531 * Transform any expressions present in the partition key
18532 *
18533 * Returns a transformed PartitionSpec.
18534 */
18537 {
18549 /* Check valid number of columns for strategy */
18556 /*
18557 * Create a dummy ParseState and insert the target relation as its sole
18558 * rangetable entry. We need a ParseState for transformExpr.
18559 */
18565 /* take care of any partition expressions */
18567 {
18571 {
18572 /* Copy, to avoid scribbling on the input */
18575 /* Now do parse transformation of the expression */
18577 EXPR_KIND_PARTITION_EXPRESSION);
18579 /* we have to fix its collations too */
18581 }
18584 }
18587 }
18589 /*
18590 * Compute per-partition-column information from a list of PartitionElems.
18591 * Expressions in the PartitionElems must be parse-analyzed already.
18592 */
18593 static void
18594 ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNumber *partattrs,
18596 PartitionStrategy strategy)
18597 {
18600 Oid am_oid;
18604 {
18606 Oid atttype;
18607 Oid attcollation;
18610 {
18611 /* Simple attribute reference */
18612 HeapTuple atttuple;
18613 Form_pg_attribute attform;
18632 /*
18633 * Generated columns cannot work: They are computed after BEFORE
18634 * triggers, but partition routing is done before all triggers.
18635 */
18648 }
18649 else
18650 {
18651 /* Expression */
18659 /*
18660 * The expression must be of a storable type (e.g., not RECORD).
18661 * The test is the same as for whether a table column is of a safe
18662 * type (which is why we needn't check for the non-expression
18663 * case).
18664 */
18670 /*
18671 * Strip any top-level COLLATE clause. This ensures that we treat
18672 * "x COLLATE y" and "(x COLLATE y)" alike.
18673 */
18679 {
18680 /*
18681 * User wrote "(column)" or "(column COLLATE something)".
18682 * Treat it like simple attribute anyway.
18683 */
18685 }
18686 else
18687 {
18694 /*
18695 * transformPartitionSpec() should have already rejected
18696 * subqueries, aggregates, window functions, and SRFs, based
18697 * on the EXPR_KIND_ for partition expressions.
18698 */
18700 /*
18701 * Cannot allow system column references, since that would
18702 * make partition routing impossible: their values won't be
18703 * known yet when we need to do that.
18704 */
18707 {
18709 expr_attrs))
18713 }
18715 /*
18716 * Generated columns cannot work: They are computed after
18717 * BEFORE triggers, but partition routing is done before all
18718 * triggers.
18719 */
18722 {
18733 }
18735 /*
18736 * Preprocess the expression before checking for mutability.
18737 * This is essential for the reasons described in
18738 * contain_mutable_functions_after_planning. However, we call
18739 * expression_planner for ourselves rather than using that
18740 * function, because if constant-folding reduces the
18741 * expression to a constant, we'd like to know that so we can
18742 * complain below.
18743 *
18744 * Like contain_mutable_functions_after_planning, assume that
18745 * expression_planner won't scribble on its input, so this
18746 * won't affect the partexprs entry we saved above.
18747 */
18750 /*
18751 * Partition expressions cannot contain mutable functions,
18752 * because a given row must always map to the same partition
18753 * as long as there is no change in the partition boundary
18754 * structure.
18755 */
18761 /*
18762 * While it is not exactly *wrong* for a partition expression
18763 * to be a constant, it seems better to reject such keys.
18764 */
18769 }
18770 }
18772 /*
18773 * Apply collation override if any
18774 */
18778 /*
18779 * Check we have a collation iff it's a collatable type. The only
18780 * expected failures here are (1) COLLATE applied to a noncollatable
18781 * type, or (2) partition expression had an unresolved collation. But
18782 * we might as well code this to be a complete consistency check.
18783 */
18785 {
18791 }
18792 else
18793 {
18799 }
18803 /*
18804 * Identify the appropriate operator class. For list and range
18805 * partitioning, we use a btree operator class; hash partitioning uses
18806 * a hash operator class.
18807 */
18810 else
18814 {
18818 {
18824 errhint("You must specify a hash operator class or define a default hash operator class for the data type.")));
18825 else
18830 errhint("You must specify a btree operator class or define a default btree operator class for the data type.")));
18831 }
18832 }
18833 else
18835 atttype,
18837 am_oid);
18839 attn++;
18840 }
18841 }
18843 /*
18844 * PartConstraintImpliedByRelConstraint
18845 * Do scanrel's existing constraints imply the partition constraint?
18846 *
18847 * "Existing constraints" include its check constraints and column-level
18848 * not-null constraints. partConstraint describes the partition constraint,
18849 * in implicit-AND form.
18850 */
18851 bool
18854 {
18860 {
18864 {
18868 {
18872 i,
18879 /*
18880 * argisrow=false is correct even for a composite column,
18881 * because attnotnull does not represent a SQL-spec IS NOT
18882 * NULL test in such a case, just IS DISTINCT FROM NULL.
18883 */
18887 }
18888 }
18889 }
18892 }
18894 /*
18895 * ConstraintImpliedByRelConstraint
18896 * Do scanrel's existing constraints imply the given constraint?
18897 *
18898 * testConstraint is the constraint to validate. provenConstraint is a
18899 * caller-provided list of conditions which this function may assume
18900 * to be true. Both provenConstraint and testConstraint must be in
18901 * implicit-AND form, must only contain immutable clauses, and must
18902 * contain only Vars with varno = 1.
18903 */
18904 bool
18905 ConstraintImpliedByRelConstraint(Relation scanrel, List *testConstraint, List *provenConstraint)
18906 {
18910 i;
18914 {
18917 /*
18918 * If this constraint hasn't been fully validated yet, we must ignore
18919 * it here.
18920 */
18924 /*
18925 * NOT ENFORCED constraints are always marked as invalid, which should
18926 * have been ignored.
18927 */
18932 /*
18933 * Run each expression through const-simplification and
18934 * canonicalization. It is necessary, because we will be comparing it
18935 * to similarly-processed partition constraint expressions, and may
18936 * fail to detect valid matches without this.
18937 */
18943 }
18945 /*
18946 * Try to make the proof. Since we are comparing CHECK constraints, we
18947 * need to use weak implication, i.e., we assume existConstraint is
18948 * not-false and try to prove the same for testConstraint.
18949 *
18950 * Note that predicate_implied_by assumes its first argument is known
18951 * immutable. That should always be true for both NOT NULL and partition
18952 * constraints, so we don't test it here.
18953 */
18955 }
18957 /*
18958 * QueuePartitionConstraintValidation
18959 *
18960 * Add an entry to wqueue to have the given partition constraint validated by
18961 * Phase 3, for the given relation, and all its children.
18962 *
18963 * We first verify whether the given constraint is implied by pre-existing
18964 * relation constraints; if it is, there's no need to scan the table to
18965 * validate, so don't queue in that case.
18966 */
18967 static void
18971 {
18972 /*
18973 * Based on the table's existing constraints, determine whether or not we
18974 * may skip scanning the table.
18975 */
18977 {
18982 else
18984 (errmsg_internal("updated partition constraint for default partition \"%s\" is implied by existing constraints",
18987 }
18989 /*
18990 * Constraints proved insufficient. For plain relations, queue a
18991 * validation item now; for partitioned tables, recurse to process each
18992 * partition.
18993 */
18995 {
18998 /* Grab a work queue entry. */
19003 }
19005 {
19010 {
19011 Relation part_rel;
19014 /*
19015 * This is the minimum lock we need to prevent deadlocks.
19016 */
19019 /*
19020 * Adjust the constraint for scanrel so that it matches this
19021 * partition's attribute numbers.
19022 */
19023 thisPartConstraint =
19028 thisPartConstraint,
19029 validate_default);
19031 }
19032 }
19033 }
19035 /*
19036 * ALTER TABLE <name> ATTACH PARTITION <partition-name> FOR VALUES
19037 *
19038 * Return the address of the newly attached partition.
19039 */
19040 static ObjectAddress
19043 {
19044 Relation attachrel,
19045 catalog;
19048 SysScanDesc scan;
19049 ScanKeyData skey;
19050 AttrNumber attno;
19052 TupleDesc tupleDesc;
19053 ObjectAddress address;
19055 Oid defaultPartOid;
19061 /*
19062 * We must lock the default partition if one exists, because attaching a
19063 * new partition will change its partition constraint.
19064 */
19065 defaultPartOid =
19072 /*
19073 * XXX I think it'd be a good idea to grab locks on all tables referenced
19074 * by FKs at this point also.
19075 */
19077 /*
19078 * Must be owner of both parent and source table -- parent was checked by
19079 * ATSimplePermissions call in ATPrepCmd
19080 */
19084 /* A partition can only have one parent */
19096 /*
19097 * Table being attached should not already be part of inheritance; either
19098 * as a child table...
19099 */
19102 Anum_pg_inherits_inhrelid,
19113 /* ...or as a parent table (except the case when it is partitioned) */
19115 Anum_pg_inherits_inhparent,
19128 /*
19129 * Prevent circularity by seeing if rel is a partition of attachrel. (In
19130 * particular, this disallows making a rel a partition of itself.)
19131 *
19132 * We do that by checking if rel is a member of the list of attachrel's
19133 * partitions provided the latter is partitioned at all. We want to avoid
19134 * having to construct this list again, so we request the strongest lock
19135 * on all partitions. We need the strongest lock, because we may decide
19136 * to scan them if we find out that the table being attached (or its leaf
19137 * partitions) may contain rows that violate the partition constraint. If
19138 * the table has a constraint that would prevent such rows, which by
19139 * definition is present in all the partitions, we need not scan the
19140 * table, nor its partitions. But we cannot risk a deadlock by taking a
19141 * weaker lock now and the stronger one only when needed.
19142 */
19153 /* If the parent is permanent, so must be all of its partitions. */
19161 /* Temp parent cannot have a partition that is itself not a temp */
19169 /* If the parent is temp, it must belong to this session */
19176 /* Ditto for the partition */
19183 /*
19184 * Check if attachrel has any identity columns or any columns that aren't
19185 * in the parent.
19186 */
19190 {
19194 /* Ignore dropped */
19205 /* Try to find the column in parent (matching on column name) */
19215 }
19217 /*
19218 * If child_rel has row-level triggers with transition tables, we
19219 * currently don't allow it to become a partition. See also prohibitions
19220 * in ATExecAddInherit() and CreateTrigger().
19221 */
19230 /*
19231 * Check that the new partition's bound is valid and does not overlap any
19232 * of existing partitions of the parent - note that it does not return on
19233 * error.
19234 */
19238 /* OK to create inheritance. Rest of the checks performed there */
19241 /* Update the pg_class entry. */
19244 /* Ensure there exists a correct set of indexes in the partition. */
19247 /* and triggers */
19250 /*
19251 * Clone foreign key constraints. Callee is responsible for setting up
19252 * for phase 3 constraint verification.
19253 */
19256 /*
19257 * Generate partition constraint from the partition bound specification.
19258 * If the parent itself is a partition, make sure to include its
19259 * constraint as well.
19260 */
19263 /*
19264 * Use list_concat_copy() to avoid modifying partBoundConstraint in place,
19265 * since it's needed later to construct the constraint expression for
19266 * validating against the default partition, if any.
19267 */
19271 /* Skip validation if there are no constraints to validate. */
19273 {
19274 /*
19275 * Run the partition quals through const-simplification similar to
19276 * check constraints. We skip canonicalize_qual, though, because
19277 * partition quals should be in canonical form already.
19278 */
19279 partConstraint =
19283 /* XXX this sure looks wrong */
19286 /*
19287 * Adjust the generated constraint to match this partition's attribute
19288 * numbers.
19289 */
19291 rel);
19293 /* Validate partition constraints against the table being attached. */
19296 }
19298 /*
19299 * If we're attaching a partition other than the default partition and a
19300 * default one exists, then that partition's partition constraint changes,
19301 * so add an entry to the work queue to validate it, too. (We must not do
19302 * this when the partition being attached is the default one; we already
19303 * did it above!)
19304 */
19306 {
19307 Relation defaultrel;
19312 /* we already hold a lock on the default partition */
19314 defPartConstraint =
19317 /*
19318 * Map the Vars in the constraint expression from rel's attnos to
19319 * defaultrel's.
19320 */
19321 defPartConstraint =
19327 /* keep our lock until commit. */
19329 }
19333 /*
19334 * If the partition we just attached is partitioned itself, invalidate
19335 * relcache for all descendent partitions too to ensure that their
19336 * rd_partcheck expression trees are rebuilt; partitions already locked at
19337 * the beginning of this function.
19338 */
19340 {
19344 {
19346 }
19347 }
19349 /* keep our lock until commit */
19353 }
19355 /*
19356 * AttachPartitionEnsureIndexes
19357 * subroutine for ATExecAttachPartition to create/match indexes
19358 *
19359 * Enforce the indexing rule for partitioned tables during ALTER TABLE / ATTACH
19360 * PARTITION: every partition must have an index attached to each index on the
19361 * partitioned table.
19362 */
19363 static void
19365 {
19371 MemoryContext cxt;
19372 MemoryContext oldcxt;
19376 ALLOCSET_DEFAULT_SIZES);
19384 /* Build arrays of all existing indexes and their IndexInfos */
19386 {
19391 }
19393 /*
19394 * If we're attaching a foreign table, we must fail if any of the indexes
19395 * is a constraint index; otherwise, there's nothing to do here. Do this
19396 * before starting work, to avoid wasting the effort of building a few
19397 * non-unique indexes before coming across a unique one.
19398 */
19400 {
19402 {
19416 }
19419 }
19421 /*
19422 * For each index on the partitioned table, find a matching one in the
19423 * partition-to-be; if one is not found, create one.
19424 */
19426 {
19432 Oid constraintOid;
19434 /*
19435 * Ignore indexes in the partitioned table other than partitioned
19436 * indexes.
19437 */
19439 {
19442 }
19444 /* construct an indexinfo to compare existing indexes against */
19451 /*
19452 * Scan the list of existing indexes in the partition-to-be, and mark
19453 * the first matching, valid, unattached one we find, if any, as
19454 * partition of the parent index. If we find one, we're done.
19455 */
19457 {
19461 /* does this index have a parent? if so, can't use it */
19465 /* If this index is invalid, can't use it */
19474 attmap))
19475 {
19476 /*
19477 * If this index is being created in the parent because of a
19478 * constraint, then the child needs to have a constraint also,
19479 * so look for one. If there is no such constraint, this
19480 * index is no good, so keep looking.
19481 */
19483 {
19484 cldConstrOid =
19486 cldIdxId);
19487 /* no dice */
19491 /* Ensure they're both the same type of constraint */
19495 }
19497 /* bingo. */
19506 }
19507 }
19509 /*
19510 * If no suitable index was found in the partition-to-be, create one
19511 * now. Note that if this is a PK, not-null constraints must already
19512 * exist.
19513 */
19515 {
19517 Oid conOid;
19524 conOid,
19527 }
19530 }
19532 out:
19533 /* Clean up. */
19538 }
19540 /*
19541 * CloneRowTriggersToPartition
19542 * subroutine for ATExecAttachPartition/DefineRelation to create row
19543 * triggers on partitions
19544 */
19545 static void
19547 {
19548 Relation pg_trigger;
19549 ScanKeyData key;
19550 SysScanDesc scan;
19551 HeapTuple tuple;
19552 MemoryContext perTupCxt;
19564 {
19568 Datum value;
19572 MemoryContext oldcxt;
19574 /*
19575 * Ignore statement-level triggers; those are not cloned.
19576 */
19580 /*
19581 * Don't clone internal triggers, because the constraint cloning code
19582 * will.
19583 */
19587 /*
19588 * Complain if we find an unexpected trigger type.
19589 */
19595 /* Use short-lived context for CREATE TRIGGER */
19598 /*
19599 * If there is a WHEN clause, generate a 'cooked' version of it that's
19600 * appropriate for the partition.
19601 */
19605 {
19611 }
19613 /*
19614 * If there is a column list, transform it to a list of column names.
19615 * Note we don't need to map this list in any way ...
19616 */
19618 {
19622 {
19623 Form_pg_attribute col;
19629 }
19630 }
19632 /* Reconstruct trigger arguments list. */
19634 {
19646 {
19649 }
19650 }
19676 }
19682 }
19684 /*
19685 * ALTER TABLE DETACH PARTITION
19686 *
19687 * Return the address of the relation that is no longer a partition of rel.
19688 *
19689 * If concurrent mode is requested, we run in two transactions. A side-
19690 * effect is that this command cannot run in a multi-part ALTER TABLE.
19691 * Currently, that's enforced by the grammar.
19692 *
19693 * The strategy for concurrency is to first modify the partition's
19694 * pg_inherit catalog row to make it visible to everyone that the
19695 * partition is detached, lock the partition against writes, and commit
19696 * the transaction; anyone who requests the partition descriptor from
19697 * that point onwards has to ignore such a partition. In a second
19698 * transaction, we wait until all transactions that could have seen the
19699 * partition as attached are gone, then we remove the rest of partition
19700 * metadata (pg_inherits and pg_class.relpartbounds).
19701 */
19702 static ObjectAddress
19705 {
19706 Relation partRel;
19707 ObjectAddress address;
19708 Oid defaultPartOid;
19710 /*
19711 * We must lock the default partition, because detaching this partition
19712 * will change its partition constraint.
19713 */
19714 defaultPartOid =
19717 {
19718 /*
19719 * Concurrent detaching when a default partition exists is not
19720 * supported. The main problem is that the default partition
19721 * constraint would change. And there's a definitional problem: what
19722 * should happen to the tuples that are being inserted that belong to
19723 * the partition being detached? Putting them on the partition being
19724 * detached would be wrong, since they'd become "lost" after the
19725 * detaching completes but we cannot put them in the default partition
19726 * either until we alter its partition constraint.
19727 *
19728 * I think we could solve this problem if we effected the constraint
19729 * change before committing the first transaction. But the lock would
19730 * have to remain AEL and it would cause concurrent query planning to
19731 * be blocked, so changing it that way would be even worse.
19732 */
19738 }
19740 /*
19741 * In concurrent mode, the partition is locked with share-update-exclusive
19742 * in the first transaction. This allows concurrent transactions to be
19743 * doing DML to the partition.
19744 */
19746 AccessExclusiveLock);
19748 /*
19749 * Check inheritance conditions and either delete the pg_inherits row (in
19750 * non-concurrent mode) or just set the inhdetachpending flag.
19751 */
19754 else
19757 /*
19758 * Ensure that foreign keys still hold after this detach. This keeps
19759 * locks on the referencing tables, which prevents concurrent transactions
19760 * from adding rows that we wouldn't see. For this to work in concurrent
19761 * mode, it is critical that the partition appears as no longer attached
19762 * for the RI queries as soon as the first transaction commits.
19763 */
19766 /*
19767 * Concurrent mode has to work harder; first we add a new constraint to
19768 * the partition that matches the partition constraint. Then we close our
19769 * existing transaction, and in a new one wait for all processes to catch
19770 * up on the catalog updates we've done so far; at that point we can
19771 * complete the operation.
19772 */
19774 {
19775 Oid partrelid,
19776 parentrelid;
19777 LOCKTAG tag;
19781 /*
19782 * Add a new constraint to the partition being detached, which
19783 * supplants the partition constraint (unless there is one already).
19784 */
19787 /*
19788 * We're almost done now; the only traces that remain are the
19789 * pg_inherits tuple and the partition's relpartbounds. Before we can
19790 * remove those, we need to wait until all transactions that know that
19791 * this is a partition are gone.
19792 */
19794 /*
19795 * Remember relation OIDs to re-acquire them later; and relation names
19796 * too, for error messages if something is dropped in between.
19797 */
19805 /* Invalidate relcache entries for the parent -- must be before close */
19812 /* Make updated catalog entry visible */
19818 /*
19819 * Now wait. This ensures that all queries that were planned
19820 * including the partition are finished before we remove the rest of
19821 * catalog entries. We don't need or indeed want to acquire this
19822 * lock, though -- that would block later queries.
19823 *
19824 * We don't need to concern ourselves with waiting for a lock on the
19825 * partition itself, since we will acquire AccessExclusiveLock below.
19826 */
19830 /*
19831 * Now acquire locks in both relations again. Note they may have been
19832 * removed in the meantime, so care is required.
19833 */
19837 /* If the relations aren't there, something bad happened; bail out */
19839 {
19842 partrelname);
19846 parentrelname)));
19847 }
19854 }
19856 /* Do the final part of detaching */
19861 /* keep our lock until commit */
19865 }
19867 /*
19868 * Second part of ALTER TABLE .. DETACH.
19869 *
19870 * This is separate so that it can be run independently when the second
19871 * transaction of the concurrent algorithm fails (crash or abort).
19872 */
19873 static void
19875 Oid defaultPartOid)
19876 {
19877 Relation classRel;
19884 HeapTuple tuple,
19885 newtuple;
19889 {
19890 /*
19891 * We can remove the pg_inherits row now. (In the non-concurrent case,
19892 * this was already done).
19893 */
19895 }
19897 /* Drop any triggers that were cloned on creation/attach. */
19900 /*
19901 * Detach any foreign keys that are inherited. This includes creating
19902 * additional action triggers.
19903 */
19908 {
19910 HeapTuple contup;
19911 Form_pg_constraint conform;
19912 Oid insertTriggerOid,
19913 updateTriggerOid;
19920 /* consider only the inherited foreign keys */
19923 {
19926 }
19928 /*
19929 * The constraint on this table must be marked no longer a child of
19930 * the parent's constraint, as do its check triggers.
19931 */
19934 /*
19935 * Also, look up the partition's "check" triggers corresponding to the
19936 * constraint being detached and detach them from the parent triggers.
19937 */
19948 /*
19949 * Lastly, create the action triggers on the referenced table, using
19950 * addFkRecurseReferenced, which requires some elaborate setup (so put
19951 * it in a separate block). While at it, if the table is partitioned,
19952 * that function will recurse to create the pg_constraint rows and
19953 * action triggers for each partition.
19954 *
19955 * Note there's no need to do addFkConstraint() here, because the
19956 * pg_constraint row already exists.
19957 */
19958 {
19968 Relation refdRel;
19972 conkey,
19973 confkey,
19974 conpfeqop,
19975 conppeqop,
19976 conffeqop,
19978 confdelsetcols);
19980 /* Create a synthetic node we'll use throughout */
19988 /* a few irrelevant fields omitted here */
20000 /* set up colnames, used to generate the constraint name */
20002 {
20003 Form_pg_attribute att;
20010 }
20015 refdRel,
20018 numfks,
20019 confkey,
20020 conkey,
20021 conpfeqop,
20022 conppeqop,
20023 conffeqop,
20024 numfkdelsetcols,
20025 confdelsetcols,
20030 }
20033 }
20038 /*
20039 * Any sub-constraints that are in the referenced-side of a larger
20040 * constraint have to be removed. This partition is no longer part of the
20041 * key space of the constraint.
20042 */
20044 {
20046 ObjectAddress constraint;
20050 constrOid,
20051 ConstraintRelationId,
20052 DEPENDENCY_INTERNAL);
20057 }
20059 /* Now we can detach indexes */
20062 {
20064 Oid parentidx;
20065 Relation idx;
20066 Oid constrOid;
20067 Oid parentConstrOid;
20078 /*
20079 * If there's a constraint associated with the index, detach it too.
20080 * Careful: it is possible for a constraint index in a partition to be
20081 * the child of a non-constraint index, so verify whether the parent
20082 * index does actually have a constraint.
20083 */
20085 idxid);
20087 parentidx);
20092 }
20094 /* Update pg_class tuple */
20103 /* Clear relpartbound and reset relispartition */
20118 /*
20119 * Drop identity property from all identity columns of partition.
20120 */
20122 {
20128 }
20131 {
20132 /*
20133 * If the relation being detached is the default partition itself,
20134 * remove it from the parent's pg_partitioned_table entry.
20135 *
20136 * If not, we must invalidate default partition's relcache entry, as
20137 * in StorePartitionBound: its partition constraint depends on every
20138 * other partition's partition constraint.
20139 */
20142 else
20144 }
20146 /*
20147 * Invalidate the parent's relcache so that the partition is no longer
20148 * included in its partition descriptor.
20149 */
20152 /*
20153 * If the partition we just detached is partitioned itself, invalidate
20154 * relcache for all descendent partitions too to ensure that their
20155 * rd_partcheck expression trees are rebuilt; must lock partitions before
20156 * doing so, using the same lockmode as what partRel has been locked with
20157 * by the caller.
20158 */
20160 {
20166 {
20168 }
20169 }
20170 }
20172 /*
20173 * ALTER TABLE ... DETACH PARTITION ... FINALIZE
20174 *
20175 * To use when a DETACH PARTITION command previously did not run to
20176 * completion; this completes the detaching process.
20177 */
20178 static ObjectAddress
20180 {
20181 Relation partRel;
20182 ObjectAddress address;
20187 /*
20188 * Wait until existing snapshots are gone. This is important if the
20189 * second transaction of DETACH PARTITION CONCURRENTLY is canceled: the
20190 * user could immediately run DETACH FINALIZE without actually waiting for
20191 * existing transactions. We must not complete the detach action until
20192 * all such queries are complete (otherwise we would present them with an
20193 * inconsistent view of catalogs).
20194 */
20204 }
20206 /*
20207 * DetachAddConstraintIfNeeded
20208 * Subroutine for ATExecDetachPartition. Create a constraint that
20209 * takes the place of the partition constraint, but avoid creating
20210 * a dupe if a constraint already exists which implies the needed
20211 * constraint.
20212 */
20213 static void
20215 {
20221 /*
20222 * Avoid adding a new constraint if the needed constraint is implied by an
20223 * existing constraint
20224 */
20226 {
20232 /* Add constraint on partition, equivalent to the partition constraint */
20243 /* It's a re-add, since it nominally already exists */
20246 }
20247 }
20249 /*
20250 * DropClonedTriggersFromPartition
20251 * subroutine for ATExecDetachPartition to remove any triggers that were
20252 * cloned to the partition when it was created-as-partition or attached.
20253 * This undoes what CloneRowTriggersToPartition did.
20254 */
20255 static void
20257 {
20258 ScanKeyData skey;
20259 SysScanDesc scan;
20260 HeapTuple trigtup;
20261 Relation tgrel;
20266 /*
20267 * Scan pg_trigger to search for all triggers on this rel.
20268 */
20275 {
20277 ObjectAddress trig;
20279 /* Ignore triggers that weren't cloned */
20283 /*
20284 * Ignore internal triggers that are implementation objects of foreign
20285 * keys, because these will be detached when the foreign keys
20286 * themselves are.
20287 */
20291 /*
20292 * This is ugly, but necessary: remove the dependency markings on the
20293 * trigger so that it can be removed.
20294 */
20296 TriggerRelationId,
20297 DEPENDENCY_PARTITION_PRI);
20299 RelationRelationId,
20300 DEPENDENCY_PARTITION_SEC);
20302 /* remember this trigger to remove it below */
20305 }
20307 /* make the dependency removal visible to the deletion below */
20311 /* done */
20315 }
20317 /*
20318 * Before acquiring lock on an index, acquire the same lock on the owning
20319 * table.
20320 */
20321 struct AttachIndexCallbackState
20322 {
20323 Oid partitionOid;
20324 Oid parentTblOid;
20326 };
20328 static void
20331 {
20333 Form_pg_class classform;
20334 HeapTuple tuple;
20339 {
20342 }
20344 /*
20345 * If we previously locked some other heap, and the name we're looking up
20346 * no longer refers to an index on that relation, release the now-useless
20347 * lock. XXX maybe we should do *after* we verify whether the index does
20348 * not actually belong to the same relation ...
20349 */
20351 {
20354 }
20356 /* Didn't find a relation, so no need for locking or permission checks. */
20371 /*
20372 * Since we need only examine the heap's tupledesc, an access share lock
20373 * on it (preventing any DDL) is sufficient.
20374 */
20377 }
20379 /*
20380 * ALTER INDEX i1 ATTACH PARTITION i2
20381 */
20382 static ObjectAddress
20384 {
20385 Relation partIdx;
20386 Relation partTbl;
20387 Relation parentTbl;
20388 ObjectAddress address;
20389 Oid partIdxId;
20390 Oid currParent;
20393 /*
20394 * We need to obtain lock on the index 'name' to modify it, but we also
20395 * need to read its owning table's tuple descriptor -- so we need to lock
20396 * both. To avoid deadlocks, obtain lock on the table before doing so on
20397 * the index. Furthermore, we need to examine the parent table of the
20398 * partition, so lock that one too.
20399 */
20403 partIdxId =
20405 RangeVarCallbackForAttachIndex,
20407 /* Not there? */
20413 /* no deadlock risk: RangeVarGetRelidExtended already acquired the lock */
20416 /* we already hold locks on both tables, so this is safe: */
20422 /* Silently do nothing if already in the right state */
20426 {
20432 PartitionDesc partDesc;
20433 Oid constraintOid,
20436 /*
20437 * If this partition already has an index attached, refuse the
20438 * operation.
20439 */
20451 /* Make sure it indexes a partition of the other index's table */
20455 {
20457 {
20460 }
20461 }
20472 /* Ensure the indexes are compatible */
20483 attmap))
20491 /*
20492 * If there is a constraint in the parent, make sure there is one in
20493 * the child too.
20494 */
20499 {
20501 partIdxId);
20508 errdetail("The index \"%s\" belongs to a constraint in table \"%s\" but no constraint exists for index \"%s\".",
20512 }
20514 /*
20515 * If it's a primary key, make sure the columns in the partition are
20516 * NOT NULL.
20517 */
20521 /* All good -- do it */
20530 }
20533 /* keep these locks till commit */
20538 }
20540 /*
20541 * Verify whether the given partition already contains an index attached
20542 * to the given partitioned index. If so, raise an error.
20543 */
20544 static void
20546 {
20547 Oid existingIdx;
20559 }
20561 /*
20562 * Verify whether the set of attached partition indexes to a parent index on
20563 * a partitioned table is complete. If it is, mark the parent index valid.
20564 *
20565 * This should be called each time a partition index is attached.
20566 */
20567 static void
20569 {
20570 Relation inheritsRel;
20571 SysScanDesc scan;
20572 ScanKeyData key;
20574 HeapTuple inhTup;
20579 /*
20580 * Scan pg_inherits for this parent index. Count each valid index we find
20581 * (verifying the pg_index entry for each), and if we reach the total
20582 * amount we expect, we can mark this parent index as valid.
20583 */
20591 {
20593 HeapTuple indTup;
20594 Form_pg_index indexForm;
20604 }
20606 /* Done with pg_inherits */
20610 /*
20611 * If we found as many inherited indexes as the partitioned table has
20612 * partitions, we're good; update pg_index to set indisvalid.
20613 */
20615 {
20616 Relation idxRel;
20617 HeapTuple indTup;
20618 Form_pg_index indexForm;
20635 }
20637 /*
20638 * If this index is in turn a partition of a larger index, validating it
20639 * might cause the parent to become valid also. Try that.
20640 */
20642 {
20643 Oid parentIdxId,
20644 parentTblId;
20645 Relation parentIdx,
20646 parentTbl;
20648 /* make sure we see the validation we just did */
20661 }
20662 }
20664 /*
20665 * When attaching an index as a partition of a partitioned index which is a
20666 * primary key, verify that all the columns in the partition are marked NOT
20667 * NULL.
20668 */
20669 static void
20671 {
20673 {
20684 }
20685 }
20687 /*
20688 * Return an OID list of constraints that reference the given relation
20689 * that are marked as having a parent constraints.
20690 */
20693 {
20694 Relation pg_constraint;
20695 HeapTuple tuple;
20696 SysScanDesc scan;
20700 /*
20701 * If no indexes, or no columns are referenceable by FKs, we can avoid the
20702 * scan.
20703 */
20706 INDEX_ATTR_BITMAP_KEY)))
20709 /* Search for constraints referencing this table */
20718 /* XXX This is a seqscan, as we don't have a usable index */
20721 {
20724 /*
20725 * We only need to process constraints that are part of larger ones.
20726 */
20731 }
20737 }
20739 /*
20740 * During DETACH PARTITION, verify that any foreign keys pointing to the
20741 * partitioned table would not become invalid. An error is raised if any
20742 * referenced values exist.
20743 */
20744 static void
20746 {
20753 {
20755 HeapTuple tuple;
20756 Form_pg_constraint constrForm;
20757 Relation rel;
20768 /* prevent data changes into the referencing table until commit */
20780 /* we needn't fill in remaining fields */
20787 }
20788 }
20790 /*
20791 * resolve column compression specification to compression method.
20792 */
20793 static char
20795 {
20801 /*
20802 * To specify a nondefault method, the column data type must be toastable.
20803 * Note this says nothing about whether the column's attstorage setting
20804 * permits compression; we intentionally allow attstorage and
20805 * attcompression to be independent. But with a non-toastable type,
20806 * attstorage could not be set to a value that would permit compression.
20807 *
20808 * We don't actually need to enforce this, since nothing bad would happen
20809 * if attcompression were non-default; it would never be consulted. But
20810 * it seems more user-friendly to complain about a certainly-useless
20811 * attempt to set the property.
20812 */
20826 }
20828 /*
20829 * resolve column storage specification
20830 */
20831 static char
20833 {
20846 else
20850 storagemode)));
20852 /*
20853 * safety check: do not allow toasted storage modes unless column datatype
20854 * is TOAST-aware.
20855 */
20863 }