src/backend/statistics/relation_stats.c

   1 /*-------------------------------------------------------------------------
   2  * relation_stats.c
   3  *
   4  *        PostgreSQL relation statistics manipulation
   5  *
   6  * Code supporting the direct import of relation statistics, similar to
   7  * what is done by the ANALYZE command.
   8  *
   9  * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
  10  * Portions Copyright (c) 1994, Regents of the University of California
  11  *
  12  * IDENTIFICATION
  13  *       src/backend/statistics/relation_stats.c
  14  *
  15  *-------------------------------------------------------------------------
  16  */
  17
  18 #include "postgres.h"
  19
  20 #include "access/heapam.h"
  21 #include "catalog/indexing.h"
  22 #include "statistics/stat_utils.h"
  23 #include "utils/fmgrprotos.h"
  24 #include "utils/syscache.h"
  25
  26 #define DEFAULT_RELPAGES Int32GetDatum(0)
  27 #define DEFAULT_RELTUPLES Float4GetDatum(-1.0)
  28 #define DEFAULT_RELALLVISIBLE Int32GetDatum(0)
  29
  30 /*
  31  * Positional argument numbers, names, and types for
  32  * relation_statistics_update().
  33  */
  34
  35 enum relation_stats_argnum
  36 {
  37         RELATION_ARG = 0,
  38         RELPAGES_ARG,
  39         RELTUPLES_ARG,
  40         RELALLVISIBLE_ARG,
  41         NUM_RELATION_STATS_ARGS
  42 };
  43
  44 static struct StatsArgInfo relarginfo[] =
  45 {
  46         [RELATION_ARG] = {"relation", REGCLASSOID},
  47         [RELPAGES_ARG] = {"relpages", INT4OID},
  48         [RELTUPLES_ARG] = {"reltuples", FLOAT4OID},
  49         [RELALLVISIBLE_ARG] = {"relallvisible", INT4OID},
  50         [NUM_RELATION_STATS_ARGS] = {0}
  51 };
  52
  53 static bool relation_statistics_update(FunctionCallInfo fcinfo, int elevel);
  54
  55 /*
  56  * Internal function for modifying statistics for a relation.
  57  */
  58 static bool
  59 relation_statistics_update(FunctionCallInfo fcinfo, int elevel)
  60 {
  61         Oid                     reloid;
  62         Relation        crel;
  63         HeapTuple       ctup;
  64         Form_pg_class pgcform;
  65         int                     replaces[3] = {0};
  66         Datum           values[3] = {0};
  67         bool            nulls[3] = {0};
  68         int                     ncols = 0;
  69         TupleDesc       tupdesc;
  70         bool            result = true;
  71
  72         stats_check_required_arg(fcinfo, relarginfo, RELATION_ARG);
  73         reloid = PG_GETARG_OID(RELATION_ARG);
  74
  75         if (RecoveryInProgress())
  76                 ereport(ERROR,
  77                                 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
  78                                  errmsg("recovery is in progress"),
  79                                  errhint("Statistics cannot be modified during recovery.")));
  80
  81         stats_lock_check_privileges(reloid);
  82
  83         /*
  84          * Take RowExclusiveLock on pg_class, consistent with
  85          * vac_update_relstats().
  86          */
  87         crel = table_open(RelationRelationId, RowExclusiveLock);
  88
  89         tupdesc = RelationGetDescr(crel);
  90         ctup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(reloid));
  91         if (!HeapTupleIsValid(ctup))
  92         {
  93                 ereport(elevel,
  94                                 (errcode(ERRCODE_OBJECT_IN_USE),
  95                                  errmsg("pg_class entry for relid %u not found", reloid)));
  96                 table_close(crel, RowExclusiveLock);
  97                 return false;
  98         }
  99
 100         pgcform = (Form_pg_class) GETSTRUCT(ctup);
 101
 102         /* relpages */
 103         if (!PG_ARGISNULL(RELPAGES_ARG))
 104         {
 105                 int32           relpages = PG_GETARG_INT32(RELPAGES_ARG);
 106
 107                 /*
 108                  * Partitioned tables may have relpages=-1. Note: for relations with
 109                  * no storage, relpages=-1 is not used consistently, but must be
 110                  * supported here.
 111                  */
 112                 if (relpages < -1)
 113                 {
 114                         ereport(elevel,
 115                                         (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 116                                          errmsg("relpages cannot be < -1")));
 117                         result = false;
 118                 }
 119                 else if (relpages != pgcform->relpages)
 120                 {
 121                         replaces[ncols] = Anum_pg_class_relpages;
 122                         values[ncols] = Int32GetDatum(relpages);
 123                         ncols++;
 124                 }
 125         }
 126
 127         if (!PG_ARGISNULL(RELTUPLES_ARG))
 128         {
 129                 float           reltuples = PG_GETARG_FLOAT4(RELTUPLES_ARG);
 130
 131                 if (reltuples < -1.0)
 132                 {
 133                         ereport(elevel,
 134                                         (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 135                                          errmsg("reltuples cannot be < -1.0")));
 136                         result = false;
 137                 }
 138                 else if (reltuples != pgcform->reltuples)
 139                 {
 140                         replaces[ncols] = Anum_pg_class_reltuples;
 141                         values[ncols] = Float4GetDatum(reltuples);
 142                         ncols++;
 143                 }
 144
 145         }
 146
 147         if (!PG_ARGISNULL(RELALLVISIBLE_ARG))
 148         {
 149                 int32           relallvisible = PG_GETARG_INT32(RELALLVISIBLE_ARG);
 150
 151                 if (relallvisible < 0)
 152                 {
 153                         ereport(elevel,
 154                                         (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 155                                          errmsg("relallvisible cannot be < 0")));
 156                         result = false;
 157                 }
 158                 else if (relallvisible != pgcform->relallvisible)
 159                 {
 160                         replaces[ncols] = Anum_pg_class_relallvisible;
 161                         values[ncols] = Int32GetDatum(relallvisible);
 162                         ncols++;
 163                 }
 164         }
 165
 166         /* only update pg_class if there is a meaningful change */
 167         if (ncols > 0)
 168         {
 169                 HeapTuple       newtup;
 170
 171                 newtup = heap_modify_tuple_by_cols(ctup, tupdesc, ncols, replaces, values,
 172                                                                                    nulls);
 173                 CatalogTupleUpdate(crel, &newtup->t_self, newtup);
 174                 heap_freetuple(newtup);
 175         }
 176
 177         /* release the lock, consistent with vac_update_relstats() */
 178         table_close(crel, RowExclusiveLock);
 179
 180         CommandCounterIncrement();
 181
 182         return result;
 183 }
 184
 185 /*
 186  * Set statistics for a given pg_class entry.
 187  */
 188 Datum
 189 pg_set_relation_stats(PG_FUNCTION_ARGS)
 190 {
 191         relation_statistics_update(fcinfo, ERROR);
 192         PG_RETURN_VOID();
 193 }
 194
 195 /*
 196  * Clear statistics for a given pg_class entry; that is, set back to initial
 197  * stats for a newly-created table.
 198  */
 199 Datum
 200 pg_clear_relation_stats(PG_FUNCTION_ARGS)
 201 {
 202         LOCAL_FCINFO(newfcinfo, 4);
 203
 204         InitFunctionCallInfoData(*newfcinfo, NULL, 4, InvalidOid, NULL, NULL);
 205
 206         newfcinfo->args[0].value = PG_GETARG_OID(0);
 207         newfcinfo->args[0].isnull = PG_ARGISNULL(0);
 208         newfcinfo->args[1].value = DEFAULT_RELPAGES;
 209         newfcinfo->args[1].isnull = false;
 210         newfcinfo->args[2].value = DEFAULT_RELTUPLES;
 211         newfcinfo->args[2].isnull = false;
 212         newfcinfo->args[3].value = DEFAULT_RELALLVISIBLE;
 213         newfcinfo->args[3].isnull = false;
 214
 215         relation_statistics_update(newfcinfo, ERROR);
 216         PG_RETURN_VOID();
 217 }
 218
 219 Datum
 220 pg_restore_relation_stats(PG_FUNCTION_ARGS)
 221 {
 222         LOCAL_FCINFO(positional_fcinfo, NUM_RELATION_STATS_ARGS);
 223         bool            result = true;
 224
 225         InitFunctionCallInfoData(*positional_fcinfo, NULL,
 226                                                          NUM_RELATION_STATS_ARGS,
 227                                                          InvalidOid, NULL, NULL);
 228
 229         if (!stats_fill_fcinfo_from_arg_pairs(fcinfo, positional_fcinfo,
 230                                                                                   relarginfo, WARNING))
 231                 result = false;
 232
 233         if (!relation_statistics_update(positional_fcinfo, WARNING))
 234                 result = false;
 235
 236         PG_RETURN_BOOL(result);
 237 }