/*-------------------------------------------------------------------------

 * relation_stats.c

 *

 *    PostgreSQL relation statistics manipulation

 *

 * Code supporting the direct import of relation statistics, similar to

 * what is done by the ANALYZE command.

 *

 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group

 * Portions Copyright (c) 1994, Regents of the University of California

 *

 * IDENTIFICATION

 *       src/backend/statistics/relation_stats.c

 *

 *-------------------------------------------------------------------------

 */

#include "postgres.h"

#include "access/heapam.h"

#include "catalog/indexing.h"

#include "catalog/namespace.h"

#include "statistics/stat_utils.h"

#include "utils/builtins.h"

#include "utils/fmgroids.h"

#include "utils/fmgrprotos.h"

#include "utils/lsyscache.h"

#include "utils/syscache.h"

/*

 * Positional argument numbers, names, and types for

 * relation_statistics_update().

 */

enum relation_stats_argnum

{

  RELSCHEMA_ARG = 0,

  RELNAME_ARG,

  RELPAGES_ARG,

  RELTUPLES_ARG,

  RELALLVISIBLE_ARG,

  RELALLFROZEN_ARG,

  NUM_RELATION_STATS_ARGS

};

static struct StatsArgInfo relarginfo[] =

{

  [RELSCHEMA_ARG] = {"schemaname", TEXTOID},

  [RELNAME_ARG] = {"relname", TEXTOID},

  [RELPAGES_ARG] = {"relpages", INT4OID},

  [RELTUPLES_ARG] = {"reltuples", FLOAT4OID},

  [RELALLVISIBLE_ARG] = {"relallvisible", INT4OID},

  [RELALLFROZEN_ARG] = {"relallfrozen", INT4OID},

  [NUM_RELATION_STATS_ARGS] = {0}

};

static bool relation_statistics_update(FunctionCallInfo fcinfo);

/*

 * Internal function for modifying statistics for a relation.

 */

static bool

relation_statistics_update(FunctionCallInfo fcinfo)

{

  bool    result = true;

  char     *nspname;

  char     *relname;

  Oid     reloid;

  Relation  crel;

  BlockNumber relpages = 0;

  bool    update_relpages = false;

  float   reltuples = 0;

  bool    update_reltuples = false;

  BlockNumber relallvisible = 0;

  bool    update_relallvisible = false;

  BlockNumber relallfrozen = 0;

  bool    update_relallfrozen = false;

  HeapTuple ctup;

  Form_pg_class pgcform;

  int     replaces[4] = {0};

  Datum   values[4] = {0};

  bool    nulls[4] = {0};

  int     nreplaces = 0;

  stats_check_required_arg(fcinfo, relarginfo, RELSCHEMA_ARG);

  stats_check_required_arg(fcinfo, relarginfo, RELNAME_ARG);

  nspname = TextDatumGetCString(PG_GETARG_DATUM(RELSCHEMA_ARG));

  relname = TextDatumGetCString(PG_GETARG_DATUM(RELNAME_ARG));

  reloid = stats_lookup_relid(nspname, relname);

  if (RecoveryInProgress())

    ereport(ERROR,

        (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),

         errmsg("recovery is in progress"),

         errhint("Statistics cannot be modified during recovery.")));

  stats_lock_check_privileges(reloid);

  if (!PG_ARGISNULL(RELPAGES_ARG))

  {

    relpages = PG_GETARG_UINT32(RELPAGES_ARG);

    update_relpages = true;

  }

  if (!PG_ARGISNULL(RELTUPLES_ARG))

  {

    reltuples = PG_GETARG_FLOAT4(RELTUPLES_ARG);

    if (reltuples < -1.0)

    {

      ereport(WARNING,

          (errcode(ERRCODE_INVALID_PARAMETER_VALUE),

           errmsg("reltuples cannot be < -1.0")));

      result = false;

    }

    else

      update_reltuples = true;

  }

  if (!PG_ARGISNULL(RELALLVISIBLE_ARG))

  {

    relallvisible = PG_GETARG_UINT32(RELALLVISIBLE_ARG);

    update_relallvisible = true;

  }

  if (!PG_ARGISNULL(RELALLFROZEN_ARG))

  {

    relallfrozen = PG_GETARG_UINT32(RELALLFROZEN_ARG);

    update_relallfrozen = true;

  }

  /*

   * Take RowExclusiveLock on pg_class, consistent with

   * vac_update_relstats().

   */

  crel = table_open(RelationRelationId, RowExclusiveLock);

  ctup = SearchSysCache1(RELOID, ObjectIdGetDatum(reloid));

  if (!HeapTupleIsValid(ctup))

    elog(ERROR, "pg_class entry for relid %u not found", reloid);

  pgcform = (Form_pg_class) GETSTRUCT(ctup);

  if (update_relpages && relpages != pgcform->relpages)

  {

    replaces[nreplaces] = Anum_pg_class_relpages;

    values[nreplaces] = UInt32GetDatum(relpages);

    nreplaces++;

  }

  if (update_reltuples && reltuples != pgcform->reltuples)

  {

    replaces[nreplaces] = Anum_pg_class_reltuples;

    values[nreplaces] = Float4GetDatum(reltuples);

    nreplaces++;

  }

  if (update_relallvisible && relallvisible != pgcform->relallvisible)

  {

    replaces[nreplaces] = Anum_pg_class_relallvisible;

    values[nreplaces] = UInt32GetDatum(relallvisible);

    nreplaces++;

  }

  if (update_relallfrozen && relallfrozen != pgcform->relallfrozen)

  {

    replaces[nreplaces] = Anum_pg_class_relallfrozen;

    values[nreplaces] = UInt32GetDatum(relallfrozen);

    nreplaces++;

  }

  if (nreplaces > 0)

  {

    TupleDesc tupdesc = RelationGetDescr(crel);

    HeapTuple newtup;

    newtup = heap_modify_tuple_by_cols(ctup, tupdesc, nreplaces,

                       replaces, values, nulls);

    CatalogTupleUpdate(crel, &newtup->t_self, newtup);

    heap_freetuple(newtup);

  }

  ReleaseSysCache(ctup);

  /* release the lock, consistent with vac_update_relstats() */

  table_close(crel, RowExclusiveLock);

  CommandCounterIncrement();

  return result;

}

/*

 * Clear statistics for a given pg_class entry; that is, set back to initial

 * stats for a newly-created table.

 */

Datum

pg_clear_relation_stats(PG_FUNCTION_ARGS)

{

  LOCAL_FCINFO(newfcinfo, 6);

  InitFunctionCallInfoData(*newfcinfo, NULL, 6, InvalidOid, NULL, NULL);

  newfcinfo->args[0].value = PG_GETARG_DATUM(0);

  newfcinfo->args[0].isnull = PG_ARGISNULL(0);

  newfcinfo->args[1].value = PG_GETARG_DATUM(1);

  newfcinfo->args[1].isnull = PG_ARGISNULL(1);

  newfcinfo->args[2].value = UInt32GetDatum(0);

  newfcinfo->args[2].isnull = false;

  newfcinfo->args[3].value = Float4GetDatum(-1.0);

  newfcinfo->args[3].isnull = false;

  newfcinfo->args[4].value = UInt32GetDatum(0);

  newfcinfo->args[4].isnull = false;

  newfcinfo->args[5].value = UInt32GetDatum(0);

  newfcinfo->args[5].isnull = false;

  relation_statistics_update(newfcinfo);

  PG_RETURN_VOID();

}

Datum

pg_restore_relation_stats(PG_FUNCTION_ARGS)

{

  LOCAL_FCINFO(positional_fcinfo, NUM_RELATION_STATS_ARGS);

  bool    result = true;

  InitFunctionCallInfoData(*positional_fcinfo, NULL,

               NUM_RELATION_STATS_ARGS,

               InvalidOid, NULL, NULL);

  if (!stats_fill_fcinfo_from_arg_pairs(fcinfo, positional_fcinfo,

                      relarginfo))

    result = false;

  if (!relation_statistics_update(positional_fcinfo))

    result = false;

  PG_RETURN_BOOL(result);

}