src/include/storage/lmgr.h

   1 /*-------------------------------------------------------------------------
   2  *
   3  * lmgr.h
   4  *        POSTGRES lock manager definitions.
   5  *
   6  *
   7  * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
   8  * Portions Copyright (c) 1994, Regents of the University of California
   9  *
  10  * src/include/storage/lmgr.h
  11  *
  12  *-------------------------------------------------------------------------
  13  */
  14 #ifndef LMGR_H
  15 #define LMGR_H
  16
  17 #include "lib/stringinfo.h"
  18 #include "storage/itemptr.h"
  19 #include "storage/lock.h"
  20 #include "utils/rel.h"
  21
  22
  23 /* XactLockTableWait operations */
  24 typedef enum XLTW_Oper
  25 {
  26         XLTW_None,
  27         XLTW_Update,
  28         XLTW_Delete,
  29         XLTW_Lock,
  30         XLTW_LockUpdated,
  31         XLTW_InsertIndex,
  32         XLTW_InsertIndexUnique,
  33         XLTW_FetchUpdated,
  34         XLTW_RecheckExclusionConstr
  35 } XLTW_Oper;
  36
  37 extern void RelationInitLockInfo(Relation relation);
  38
  39 /* Lock a relation */
  40 extern void LockRelationOid(Oid relid, LOCKMODE lockmode);
  41 extern bool ConditionalLockRelationOid(Oid relid, LOCKMODE lockmode);
  42 extern void UnlockRelationId(LockRelId *relid, LOCKMODE lockmode);
  43 extern void UnlockRelationOid(Oid relid, LOCKMODE lockmode);
  44
  45 extern void LockRelation(Relation relation, LOCKMODE lockmode);
  46 extern bool ConditionalLockRelation(Relation relation, LOCKMODE lockmode);
  47 extern void UnlockRelation(Relation relation, LOCKMODE lockmode);
  48 extern bool CheckRelationLockedByMe(Relation relation, LOCKMODE lockmode,
  49                                                                         bool orstronger);
  50 extern bool LockHasWaitersRelation(Relation relation, LOCKMODE lockmode);
  51
  52 extern void LockRelationIdForSession(LockRelId *relid, LOCKMODE lockmode);
  53 extern void UnlockRelationIdForSession(LockRelId *relid, LOCKMODE lockmode);
  54
  55 /* Lock a relation for extension */
  56 extern void LockRelationForExtension(Relation relation, LOCKMODE lockmode);
  57 extern void UnlockRelationForExtension(Relation relation, LOCKMODE lockmode);
  58 extern bool ConditionalLockRelationForExtension(Relation relation,
  59                                                                                                 LOCKMODE lockmode);
  60 extern int      RelationExtensionLockWaiterCount(Relation relation);
  61
  62 /* Lock to recompute pg_database.datfrozenxid in the current database */
  63 extern void LockDatabaseFrozenIds(LOCKMODE lockmode);
  64
  65 /* Lock a page (currently only used within indexes) */
  66 extern void LockPage(Relation relation, BlockNumber blkno, LOCKMODE lockmode);
  67 extern bool ConditionalLockPage(Relation relation, BlockNumber blkno, LOCKMODE lockmode);
  68 extern void UnlockPage(Relation relation, BlockNumber blkno, LOCKMODE lockmode);
  69
  70 /* Lock a tuple (see heap_lock_tuple before assuming you understand this) */
  71 extern void LockTuple(Relation relation, ItemPointer tid, LOCKMODE lockmode);
  72 extern bool ConditionalLockTuple(Relation relation, ItemPointer tid,
  73                                                                  LOCKMODE lockmode);
  74 extern void UnlockTuple(Relation relation, ItemPointer tid, LOCKMODE lockmode);
  75
  76 /* Lock an XID (used to wait for a transaction to finish) */
  77 extern void XactLockTableInsert(TransactionId xid);
  78 extern void XactLockTableDelete(TransactionId xid);
  79 extern void XactLockTableWait(TransactionId xid, Relation rel,
  80                                                           ItemPointer ctid, XLTW_Oper oper);
  81 extern bool ConditionalXactLockTableWait(TransactionId xid);
  82
  83 /* Lock VXIDs, specified by conflicting locktags */
  84 extern void WaitForLockers(LOCKTAG heaplocktag, LOCKMODE lockmode, bool progress);
  85 extern void WaitForLockersMultiple(List *locktags, LOCKMODE lockmode, bool progress);
  86
  87 /* Lock an XID for tuple insertion (used to wait for an insertion to finish) */
  88 extern uint32 SpeculativeInsertionLockAcquire(TransactionId xid);
  89 extern void SpeculativeInsertionLockRelease(TransactionId xid);
  90 extern void SpeculativeInsertionWait(TransactionId xid, uint32 token);
  91
  92 /* Lock a general object (other than a relation) of the current database */
  93 extern void LockDatabaseObject(Oid classid, Oid objid, uint16 objsubid,
  94                                                            LOCKMODE lockmode);
  95 extern void UnlockDatabaseObject(Oid classid, Oid objid, uint16 objsubid,
  96                                                                  LOCKMODE lockmode);
  97
  98 /* Lock a shared-across-databases object (other than a relation) */
  99 extern void LockSharedObject(Oid classid, Oid objid, uint16 objsubid,
 100                                                          LOCKMODE lockmode);
 101 extern void UnlockSharedObject(Oid classid, Oid objid, uint16 objsubid,
 102                                                            LOCKMODE lockmode);
 103
 104 extern void LockSharedObjectForSession(Oid classid, Oid objid, uint16 objsubid,
 105                                                                            LOCKMODE lockmode);
 106 extern void UnlockSharedObjectForSession(Oid classid, Oid objid, uint16 objsubid,
 107                                                                                  LOCKMODE lockmode);
 108
 109 /* Describe a locktag for error messages */
 110 extern void DescribeLockTag(StringInfo buf, const LOCKTAG *tag);
 111
 112 extern const char *GetLockNameFromTagType(uint16 locktag_type);
 113
 114 #endif                                                  /* LMGR_H */