#include "postgres.h"
#include <math.h>
#include "access/clog.h"
#include "access/commit_ts.h"
#include "access/genam.h"
#include "access/heapam.h"
#include "access/htup_details.h"
#include "access/multixact.h"
#include "access/transam.h"
#include "access/xact.h"
#include "catalog/namespace.h"
#include "catalog/pg_database.h"
#include "catalog/pg_inherits_fn.h"
#include "catalog/pg_namespace.h"
#include "commands/cluster.h"
#include "commands/vacuum.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/bufmgr.h"
#include "storage/lmgr.h"
#include "storage/proc.h"
#include "storage/procarray.h"
#include "utils/acl.h"
#include "utils/fmgroids.h"
#include "utils/guc.h"
#include "utils/memutils.h"
#include "utils/snapmgr.h"
#include "utils/syscache.h"
#include "utils/tqual.h"

Include dependency graph for vacuum.c:

Functions
static List *	get_rel_oids (Oid relid, const RangeVar *vacrel)

static void	vac_truncate_clog (TransactionId frozenXID, MultiXactId minMulti, TransactionId lastSaneFrozenXid, MultiXactId lastSaneMinMulti)

static bool	vacuum_rel (Oid relid, RangeVar relation, int options, VacuumParams params)

void	ExecVacuum (VacuumStmt *vacstmt, bool isTopLevel)

void	vacuum (int options, RangeVar relation, Oid relid, VacuumParams params, List *va_cols, BufferAccessStrategy bstrategy, bool isTopLevel)

void	vacuum_set_xid_limits (Relation rel, int freeze_min_age, int freeze_table_age, int multixact_freeze_min_age, int multixact_freeze_table_age, TransactionId oldestXmin, TransactionId freezeLimit, TransactionId xidFullScanLimit, MultiXactId multiXactCutoff, MultiXactId *mxactFullScanLimit)

double	vac_estimate_reltuples (Relation relation, bool is_analyze, BlockNumber total_pages, BlockNumber scanned_pages, double scanned_tuples)

void	vac_update_relstats (Relation relation, BlockNumber num_pages, double num_tuples, BlockNumber num_all_visible_pages, bool hasindex, TransactionId frozenxid, MultiXactId minmulti, bool in_outer_xact)

void	vac_update_datfrozenxid (void)

void	vac_open_indexes (Relation relation, LOCKMODE lockmode, int nindexes, Relation *Irel)

void	vac_close_indexes (int nindexes, Relation *Irel, LOCKMODE lockmode)

void	vacuum_delay_point (void)

Variables
int	vacuum_freeze_min_age

int	vacuum_freeze_table_age

int	vacuum_multixact_freeze_min_age

int	vacuum_multixact_freeze_table_age

static MemoryContext	vac_context = NULL

static BufferAccessStrategy	vac_strategy

Function Documentation

void ExecVacuum	(	VacuumStmt *	vacstmt,
		bool	isTopLevel
	)

Definition at line 85 of file vacuum.c.

References Assert, VacuumParams::freeze_min_age, VacuumParams::freeze_table_age, InvalidOid, VacuumParams::is_wraparound, VacuumParams::log_min_duration, VacuumParams::multixact_freeze_min_age, VacuumParams::multixact_freeze_table_age, NIL, VacuumStmt::options, VacuumStmt::relation, VacuumStmt::va_cols, VACOPT_ANALYZE, VACOPT_FREEZE, VACOPT_FULL, VACOPT_SKIPTOAST, VACOPT_VACUUM, and vacuum().

Referenced by standard_ProcessUtility().

 {
     VacuumParams params;
 
     /* sanity checks on options */
     Assert(vacstmt->options & (VACOPT_VACUUM | VACOPT_ANALYZE));
     Assert((vacstmt->options & VACOPT_VACUUM) ||
            !(vacstmt->options & (VACOPT_FULL | VACOPT_FREEZE)));
     Assert((vacstmt->options & VACOPT_ANALYZE) || vacstmt->va_cols == NIL);
     Assert(!(vacstmt->options & VACOPT_SKIPTOAST));
 
     /*
      * All freeze ages are zero if the FREEZE option is given; otherwise pass
      * them as -1 which means to use the default values.
      */
     if (vacstmt->options & VACOPT_FREEZE)
     {
         params.freeze_min_age = 0;
         params.freeze_table_age = 0;
         params.multixact_freeze_min_age = 0;
         params.multixact_freeze_table_age = 0;
     }
     else
     {
         params.freeze_min_age = -1;
         params.freeze_table_age = -1;
         params.multixact_freeze_min_age = -1;
         params.multixact_freeze_table_age = -1;
     }
 
     /* user-invoked vacuum is never "for wraparound" */
     params.is_wraparound = false;
 
     /* user-invoked vacuum never uses this parameter */
     params.log_min_duration = -1;
 
     /* Now go through the common routine */
     vacuum(vacstmt->options, vacstmt->relation, InvalidOid, &params,
            vacstmt->va_cols, NULL, isTopLevel);
 }

static List * get_rel_oids	(	Oid	relid,
		const RangeVar *	vacrel
	)

static

Definition at line 382 of file vacuum.c.

References AccessShareLock, elog, ERROR, find_all_inheritors(), ForwardScanDirection, GETSTRUCT, heap_beginscan_catalog(), heap_close, heap_endscan(), heap_getnext(), heap_open(), HeapTupleGetOid, HeapTupleIsValid, lappend_oid(), list_concat(), MemoryContextSwitchTo(), NIL, NoLock, ObjectIdGetDatum, OidIsValid, RangeVarGetRelid, RelationRelationId, ReleaseSysCache(), RELKIND_MATVIEW, RELKIND_PARTITIONED_TABLE, RELKIND_RELATION, RELOID, and SearchSysCache1.

Referenced by vacuum().

 {
     List       *oid_list = NIL;
     MemoryContext oldcontext;
 
     /* OID supplied by VACUUM's caller? */
     if (OidIsValid(relid))
     {
         oldcontext = MemoryContextSwitchTo(vac_context);
         oid_list = lappend_oid(oid_list, relid);
         MemoryContextSwitchTo(oldcontext);
     }
     else if (vacrel)
     {
         /* Process a specific relation */
         Oid         relid;
         HeapTuple   tuple;
         Form_pg_class classForm;
         bool        include_parts;
 
         /*
          * Since we don't take a lock here, the relation might be gone, or the
          * RangeVar might no longer refer to the OID we look up here.  In the
          * former case, VACUUM will do nothing; in the latter case, it will
          * process the OID we looked up here, rather than the new one. Neither
          * is ideal, but there's little practical alternative, since we're
          * going to commit this transaction and begin a new one between now
          * and then.
          */
         relid = RangeVarGetRelid(vacrel, NoLock, false);
 
         /*
          * To check whether the relation is a partitioned table, fetch its
          * syscache entry.
          */
         tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
         if (!HeapTupleIsValid(tuple))
             elog(ERROR, "cache lookup failed for relation %u", relid);
         classForm = (Form_pg_class) GETSTRUCT(tuple);
         include_parts = (classForm->relkind == RELKIND_PARTITIONED_TABLE);
         ReleaseSysCache(tuple);
 
         /*
          * Make relation list entries for this guy and its partitions, if any.
          * Note that the list returned by find_all_inheritors() include the
          * passed-in OID at its head.  Also note that we did not request a
          * lock to be taken to match what would be done otherwise.
          */
         oldcontext = MemoryContextSwitchTo(vac_context);
         if (include_parts)
             oid_list = list_concat(oid_list,
                                    find_all_inheritors(relid, NoLock, NULL));
         else
             oid_list = lappend_oid(oid_list, relid);
         MemoryContextSwitchTo(oldcontext);
     }
     else
     {
         /*
          * Process all plain relations and materialized views listed in
          * pg_class
          */
         Relation    pgclass;
         HeapScanDesc scan;
         HeapTuple   tuple;
 
         pgclass = heap_open(RelationRelationId, AccessShareLock);
 
         scan = heap_beginscan_catalog(pgclass, 0, NULL);
 
         while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
         {
             Form_pg_class classForm = (Form_pg_class) GETSTRUCT(tuple);
 
             /*
              * We include partitioned tables here; depending on which
              * operation is to be performed, caller will decide whether to
              * process or ignore them.
              */
             if (classForm->relkind != RELKIND_RELATION &&
                 classForm->relkind != RELKIND_MATVIEW &&
                 classForm->relkind != RELKIND_PARTITIONED_TABLE)
                 continue;
 
             /* Make a relation list entry for this guy */
             oldcontext = MemoryContextSwitchTo(vac_context);
             oid_list = lappend_oid(oid_list, HeapTupleGetOid(tuple));
             MemoryContextSwitchTo(oldcontext);
         }
 
         heap_endscan(scan);
         heap_close(pgclass, AccessShareLock);
     }
 
     return oid_list;
 }

void vac_close_indexes	(	int	nindexes,
		Relation *	Irel,
		LOCKMODE	lockmode
	)

Definition at line 1539 of file vacuum.c.

References index_close(), and pfree().

Referenced by do_analyze_rel(), and lazy_vacuum_rel().

 {
     if (Irel == NULL)
         return;
 
     while (nindexes--)
     {
         Relation    ind = Irel[nindexes];
 
         index_close(ind, lockmode);
     }
     pfree(Irel);
 }

double vac_estimate_reltuples	(	Relation	relation,
		bool	is_analyze,
		BlockNumber	total_pages,
		BlockNumber	scanned_pages,
		double	scanned_tuples
	)

Definition at line 685 of file vacuum.c.

References RelationData::rd_rel.

Referenced by acquire_sample_rows(), lazy_scan_heap(), and statapprox_heap().

 {
     BlockNumber old_rel_pages = relation->rd_rel->relpages;
     double      old_rel_tuples = relation->rd_rel->reltuples;
     double      old_density;
     double      new_density;
     double      multiplier;
     double      updated_density;
 
     /* If we did scan the whole table, just use the count as-is */
     if (scanned_pages >= total_pages)
         return scanned_tuples;
 
     /*
      * If scanned_pages is zero but total_pages isn't, keep the existing value
      * of reltuples.  (Note: callers should avoid updating the pg_class
      * statistics in this situation, since no new information has been
      * provided.)
      */
     if (scanned_pages == 0)
         return old_rel_tuples;
 
     /*
      * If old value of relpages is zero, old density is indeterminate; we
      * can't do much except scale up scanned_tuples to match total_pages.
      */
     if (old_rel_pages == 0)
         return floor((scanned_tuples / scanned_pages) * total_pages + 0.5);
 
     /*
      * Okay, we've covered the corner cases.  The normal calculation is to
      * convert the old measurement to a density (tuples per page), then update
      * the density using an exponential-moving-average approach, and finally
      * compute reltuples as updated_density * total_pages.
      *
      * For ANALYZE, the moving average multiplier is just the fraction of the
      * table's pages we scanned.  This is equivalent to assuming that the
      * tuple density in the unscanned pages didn't change.  Of course, it
      * probably did, if the new density measurement is different. But over
      * repeated cycles, the value of reltuples will converge towards the
      * correct value, if repeated measurements show the same new density.
      *
      * For VACUUM, the situation is a bit different: we have looked at a
      * nonrandom sample of pages, but we know for certain that the pages we
      * didn't look at are precisely the ones that haven't changed lately.
      * Thus, there is a reasonable argument for doing exactly the same thing
      * as for the ANALYZE case, that is use the old density measurement as the
      * value for the unscanned pages.
      *
      * This logic could probably use further refinement.
      */
     old_density = old_rel_tuples / old_rel_pages;
     new_density = scanned_tuples / scanned_pages;
     multiplier = (double) scanned_pages / (double) total_pages;
     updated_density = old_density + (new_density - old_density) * multiplier;
     return floor(updated_density * total_pages + 0.5);
 }

void vac_open_indexes	(	Relation	relation,
		LOCKMODE	lockmode,
		int *	nindexes,
		Relation **	Irel
	)

Definition at line 1496 of file vacuum.c.

References Assert, i, index_close(), index_open(), IndexIsReady, lfirst_oid, list_free(), list_length(), NoLock, palloc(), RelationData::rd_index, and RelationGetIndexList().

Referenced by do_analyze_rel(), and lazy_vacuum_rel().

 {
     List       *indexoidlist;
     ListCell   *indexoidscan;
     int         i;
 
     Assert(lockmode != NoLock);
 
     indexoidlist = RelationGetIndexList(relation);
 
     /* allocate enough memory for all indexes */
     i = list_length(indexoidlist);
 
     if (i > 0)
         *Irel = (Relation *) palloc(i * sizeof(Relation));
     else
         *Irel = NULL;
 
     /* collect just the ready indexes */
     i = 0;
     foreach(indexoidscan, indexoidlist)
     {
         Oid         indexoid = lfirst_oid(indexoidscan);
         Relation    indrel;
 
         indrel = index_open(indexoid, lockmode);
         if (IndexIsReady(indrel->rd_index))
             (*Irel)[i++] = indrel;
         else
             index_close(indrel, lockmode);
     }
 
     *nindexes = i;
 
     list_free(indexoidlist);
 }

static void vac_truncate_clog	(	TransactionId	frozenXID,
		MultiXactId	minMulti,
		TransactionId	lastSaneFrozenXid,
		MultiXactId	lastSaneMinMulti
	)

static

Definition at line 1086 of file vacuum.c.

References AccessShareLock, AdvanceOldestCommitTsXid(), Assert, DatabaseRelationId, ereport, errdetail(), errmsg(), FormData_pg_database, ForwardScanDirection, GETSTRUCT, heap_beginscan_catalog(), heap_close, heap_endscan(), heap_getnext(), heap_open(), HeapTupleGetOid, MultiXactIdIsValid, MultiXactIdPrecedes(), MyDatabaseId, ReadNewTransactionId(), SetMultiXactIdLimit(), SetTransactionIdLimit(), TransactionIdIsNormal, TransactionIdPrecedes(), TruncateCLOG(), TruncateCommitTs(), TruncateMultiXact(), and WARNING.

Referenced by vac_update_datfrozenxid().

 {
     TransactionId nextXID = ReadNewTransactionId();
     Relation    relation;
     HeapScanDesc scan;
     HeapTuple   tuple;
     Oid         oldestxid_datoid;
     Oid         minmulti_datoid;
     bool        bogus = false;
     bool        frozenAlreadyWrapped = false;
 
     /* init oldest datoids to sync with my frozenXID/minMulti values */
     oldestxid_datoid = MyDatabaseId;
     minmulti_datoid = MyDatabaseId;
 
     /*
      * Scan pg_database to compute the minimum datfrozenxid/datminmxid
      *
      * Since vac_update_datfrozenxid updates datfrozenxid/datminmxid in-place,
      * the values could change while we look at them.  Fetch each one just
      * once to ensure sane behavior of the comparison logic.  (Here, as in
      * many other places, we assume that fetching or updating an XID in shared
      * storage is atomic.)
      *
      * Note: we need not worry about a race condition with new entries being
      * inserted by CREATE DATABASE.  Any such entry will have a copy of some
      * existing DB's datfrozenxid, and that source DB cannot be ours because
      * of the interlock against copying a DB containing an active backend.
      * Hence the new entry will not reduce the minimum.  Also, if two VACUUMs
      * concurrently modify the datfrozenxid's of different databases, the
      * worst possible outcome is that pg_xact is not truncated as aggressively
      * as it could be.
      */
     relation = heap_open(DatabaseRelationId, AccessShareLock);
 
     scan = heap_beginscan_catalog(relation, 0, NULL);
 
     while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
     {
         volatile FormData_pg_database *dbform = (Form_pg_database) GETSTRUCT(tuple);
         TransactionId datfrozenxid = dbform->datfrozenxid;
         TransactionId datminmxid = dbform->datminmxid;
 
         Assert(TransactionIdIsNormal(datfrozenxid));
         Assert(MultiXactIdIsValid(datminmxid));
 
         /*
          * If things are working properly, no database should have a
          * datfrozenxid or datminmxid that is "in the future".  However, such
          * cases have been known to arise due to bugs in pg_upgrade.  If we
          * see any entries that are "in the future", chicken out and don't do
          * anything.  This ensures we won't truncate clog before those
          * databases have been scanned and cleaned up.  (We will issue the
          * "already wrapped" warning if appropriate, though.)
          */
         if (TransactionIdPrecedes(lastSaneFrozenXid, datfrozenxid) ||
             MultiXactIdPrecedes(lastSaneMinMulti, datminmxid))
             bogus = true;
 
         if (TransactionIdPrecedes(nextXID, datfrozenxid))
             frozenAlreadyWrapped = true;
         else if (TransactionIdPrecedes(datfrozenxid, frozenXID))
         {
             frozenXID = datfrozenxid;
             oldestxid_datoid = HeapTupleGetOid(tuple);
         }
 
         if (MultiXactIdPrecedes(datminmxid, minMulti))
         {
             minMulti = datminmxid;
             minmulti_datoid = HeapTupleGetOid(tuple);
         }
     }
 
     heap_endscan(scan);
 
     heap_close(relation, AccessShareLock);
 
     /*
      * Do not truncate CLOG if we seem to have suffered wraparound already;
      * the computed minimum XID might be bogus.  This case should now be
      * impossible due to the defenses in GetNewTransactionId, but we keep the
      * test anyway.
      */
     if (frozenAlreadyWrapped)
     {
         ereport(WARNING,
                 (errmsg("some databases have not been vacuumed in over 2 billion transactions"),
                  errdetail("You might have already suffered transaction-wraparound data loss.")));
         return;
     }
 
     /* chicken out if data is bogus in any other way */
     if (bogus)
         return;
 
     /*
      * Advance the oldest value for commit timestamps before truncating, so
      * that if a user requests a timestamp for a transaction we're truncating
      * away right after this point, they get NULL instead of an ugly "file not
      * found" error from slru.c.  This doesn't matter for xact/multixact
      * because they are not subject to arbitrary lookups from users.
      */
     AdvanceOldestCommitTsXid(frozenXID);
 
     /*
      * Truncate CLOG, multixact and CommitTs to the oldest computed value.
      */
     TruncateCLOG(frozenXID, oldestxid_datoid);
     TruncateCommitTs(frozenXID);
     TruncateMultiXact(minMulti, minmulti_datoid);
 
     /*
      * Update the wrap limit for GetNewTransactionId and creation of new
      * MultiXactIds.  Note: these functions will also signal the postmaster
      * for an(other) autovac cycle if needed.   XXX should we avoid possibly
      * signalling twice?
      */
     SetTransactionIdLimit(frozenXID, oldestxid_datoid);
     SetMultiXactIdLimit(minMulti, minmulti_datoid, false);
 }

void vac_update_datfrozenxid ( void )

Definition at line 922 of file vacuum.c.

References AccessShareLock, Assert, DATABASEOID, DatabaseRelationId, elog, ERROR, ForceTransactionIdLimitUpdate(), GetOldestMultiXactId(), GetOldestXmin(), GETSTRUCT, heap_close, heap_freetuple(), heap_inplace_update(), heap_open(), HeapTupleIsValid, InvalidOid, MultiXactIdIsValid, MultiXactIdPrecedes(), MyDatabaseId, ObjectIdGetDatum, PROCARRAY_FLAGS_VACUUM, ReadNewTransactionId(), ReadNextMultiXactId(), RelationRelationId, RELKIND_MATVIEW, RELKIND_RELATION, RELKIND_TOASTVALUE, RowExclusiveLock, SearchSysCacheCopy1, systable_beginscan(), systable_endscan(), systable_getnext(), TransactionIdIsNormal, TransactionIdPrecedes(), and vac_truncate_clog().

Referenced by do_autovacuum(), and vacuum().

 {
     HeapTuple   tuple;
     Form_pg_database dbform;
     Relation    relation;
     SysScanDesc scan;
     HeapTuple   classTup;
     TransactionId newFrozenXid;
     MultiXactId newMinMulti;
     TransactionId lastSaneFrozenXid;
     MultiXactId lastSaneMinMulti;
     bool        bogus = false;
     bool        dirty = false;
 
     /*
      * Initialize the "min" calculation with GetOldestXmin, which is a
      * reasonable approximation to the minimum relfrozenxid for not-yet-
      * committed pg_class entries for new tables; see AddNewRelationTuple().
      * So we cannot produce a wrong minimum by starting with this.
      */
     newFrozenXid = GetOldestXmin(NULL, PROCARRAY_FLAGS_VACUUM);
 
     /*
      * Similarly, initialize the MultiXact "min" with the value that would be
      * used on pg_class for new tables.  See AddNewRelationTuple().
      */
     newMinMulti = GetOldestMultiXactId();
 
     /*
      * Identify the latest relfrozenxid and relminmxid values that we could
      * validly see during the scan.  These are conservative values, but it's
      * not really worth trying to be more exact.
      */
     lastSaneFrozenXid = ReadNewTransactionId();
     lastSaneMinMulti = ReadNextMultiXactId();
 
     /*
      * We must seqscan pg_class to find the minimum Xid, because there is no
      * index that can help us here.
      */
     relation = heap_open(RelationRelationId, AccessShareLock);
 
     scan = systable_beginscan(relation, InvalidOid, false,
                               NULL, 0, NULL);
 
     while ((classTup = systable_getnext(scan)) != NULL)
     {
         Form_pg_class classForm = (Form_pg_class) GETSTRUCT(classTup);
 
         /*
          * Only consider relations able to hold unfrozen XIDs (anything else
          * should have InvalidTransactionId in relfrozenxid anyway.)
          */
         if (classForm->relkind != RELKIND_RELATION &&
             classForm->relkind != RELKIND_MATVIEW &&
             classForm->relkind != RELKIND_TOASTVALUE)
             continue;
 
         Assert(TransactionIdIsNormal(classForm->relfrozenxid));
         Assert(MultiXactIdIsValid(classForm->relminmxid));
 
         /*
          * If things are working properly, no relation should have a
          * relfrozenxid or relminmxid that is "in the future".  However, such
          * cases have been known to arise due to bugs in pg_upgrade.  If we
          * see any entries that are "in the future", chicken out and don't do
          * anything.  This ensures we won't truncate clog before those
          * relations have been scanned and cleaned up.
          */
         if (TransactionIdPrecedes(lastSaneFrozenXid, classForm->relfrozenxid) ||
             MultiXactIdPrecedes(lastSaneMinMulti, classForm->relminmxid))
         {
             bogus = true;
             break;
         }
 
         if (TransactionIdPrecedes(classForm->relfrozenxid, newFrozenXid))
             newFrozenXid = classForm->relfrozenxid;
 
         if (MultiXactIdPrecedes(classForm->relminmxid, newMinMulti))
             newMinMulti = classForm->relminmxid;
     }
 
     /* we're done with pg_class */
     systable_endscan(scan);
     heap_close(relation, AccessShareLock);
 
     /* chicken out if bogus data found */
     if (bogus)
         return;
 
     Assert(TransactionIdIsNormal(newFrozenXid));
     Assert(MultiXactIdIsValid(newMinMulti));
 
     /* Now fetch the pg_database tuple we need to update. */
     relation = heap_open(DatabaseRelationId, RowExclusiveLock);
 
     /* Fetch a copy of the tuple to scribble on */
     tuple = SearchSysCacheCopy1(DATABASEOID, ObjectIdGetDatum(MyDatabaseId));
     if (!HeapTupleIsValid(tuple))
         elog(ERROR, "could not find tuple for database %u", MyDatabaseId);
     dbform = (Form_pg_database) GETSTRUCT(tuple);
 
     /*
      * As in vac_update_relstats(), we ordinarily don't want to let
      * datfrozenxid go backward; but if it's "in the future" then it must be
      * corrupt and it seems best to overwrite it.
      */
     if (dbform->datfrozenxid != newFrozenXid &&
         (TransactionIdPrecedes(dbform->datfrozenxid, newFrozenXid) ||
          TransactionIdPrecedes(lastSaneFrozenXid, dbform->datfrozenxid)))
     {
         dbform->datfrozenxid = newFrozenXid;
         dirty = true;
     }
     else
         newFrozenXid = dbform->datfrozenxid;
 
     /* Ditto for datminmxid */
     if (dbform->datminmxid != newMinMulti &&
         (MultiXactIdPrecedes(dbform->datminmxid, newMinMulti) ||
          MultiXactIdPrecedes(lastSaneMinMulti, dbform->datminmxid)))
     {
         dbform->datminmxid = newMinMulti;
         dirty = true;
     }
     else
         newMinMulti = dbform->datminmxid;
 
     if (dirty)
         heap_inplace_update(relation, tuple);
 
     heap_freetuple(tuple);
     heap_close(relation, RowExclusiveLock);
 
     /*
      * If we were able to advance datfrozenxid or datminmxid, see if we can
      * truncate pg_xact and/or pg_multixact.  Also do it if the shared
      * XID-wrap-limit info is stale, since this action will update that too.
      */
     if (dirty || ForceTransactionIdLimitUpdate())
         vac_truncate_clog(newFrozenXid, newMinMulti,
                           lastSaneFrozenXid, lastSaneMinMulti);
 }

void vac_update_relstats	(	Relation	relation,
		BlockNumber	num_pages,
		double	num_tuples,
		BlockNumber	num_all_visible_pages,
		bool	hasindex,
		TransactionId	frozenxid,
		MultiXactId	minmulti,
		bool	in_outer_xact
	)

Definition at line 785 of file vacuum.c.

References elog, ERROR, GETSTRUCT, heap_close, heap_inplace_update(), heap_open(), HeapTupleIsValid, MultiXactIdIsValid, MultiXactIdPrecedes(), ObjectIdGetDatum, RelationData::rd_rules, ReadNewTransactionId(), ReadNextMultiXactId(), RelationGetRelid, RelationRelationId, RELOID, RowExclusiveLock, SearchSysCacheCopy1, TransactionIdIsNormal, TransactionIdPrecedes(), and RelationData::trigdesc.

Referenced by do_analyze_rel(), lazy_cleanup_index(), and lazy_vacuum_rel().

 {
     Oid         relid = RelationGetRelid(relation);
     Relation    rd;
     HeapTuple   ctup;
     Form_pg_class pgcform;
     bool        dirty;
 
     rd = heap_open(RelationRelationId, RowExclusiveLock);
 
     /* Fetch a copy of the tuple to scribble on */
     ctup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
     if (!HeapTupleIsValid(ctup))
         elog(ERROR, "pg_class entry for relid %u vanished during vacuuming",
              relid);
     pgcform = (Form_pg_class) GETSTRUCT(ctup);
 
     /* Apply statistical updates, if any, to copied tuple */
 
     dirty = false;
     if (pgcform->relpages != (int32) num_pages)
     {
         pgcform->relpages = (int32) num_pages;
         dirty = true;
     }
     if (pgcform->reltuples != (float4) num_tuples)
     {
         pgcform->reltuples = (float4) num_tuples;
         dirty = true;
     }
     if (pgcform->relallvisible != (int32) num_all_visible_pages)
     {
         pgcform->relallvisible = (int32) num_all_visible_pages;
         dirty = true;
     }
 
     /* Apply DDL updates, but not inside an outer transaction (see above) */
 
     if (!in_outer_xact)
     {
         /*
          * If we didn't find any indexes, reset relhasindex.
          */
         if (pgcform->relhasindex && !hasindex)
         {
             pgcform->relhasindex = false;
             dirty = true;
         }
 
         /*
          * If we have discovered that there are no indexes, then there's no
          * primary key either.  This could be done more thoroughly...
          */
         if (pgcform->relhaspkey && !hasindex)
         {
             pgcform->relhaspkey = false;
             dirty = true;
         }
 
         /* We also clear relhasrules and relhastriggers if needed */
         if (pgcform->relhasrules && relation->rd_rules == NULL)
         {
             pgcform->relhasrules = false;
             dirty = true;
         }
         if (pgcform->relhastriggers && relation->trigdesc == NULL)
         {
             pgcform->relhastriggers = false;
             dirty = true;
         }
     }
 
     /*
      * Update relfrozenxid, unless caller passed InvalidTransactionId
      * indicating it has no new data.
      *
      * Ordinarily, we don't let relfrozenxid go backwards: if things are
      * working correctly, the only way the new frozenxid could be older would
      * be if a previous VACUUM was done with a tighter freeze_min_age, in
      * which case we don't want to forget the work it already did.  However,
      * if the stored relfrozenxid is "in the future", then it must be corrupt
      * and it seems best to overwrite it with the cutoff we used this time.
      * This should match vac_update_datfrozenxid() concerning what we consider
      * to be "in the future".
      */
     if (TransactionIdIsNormal(frozenxid) &&
         pgcform->relfrozenxid != frozenxid &&
         (TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
          TransactionIdPrecedes(ReadNewTransactionId(),
                                pgcform->relfrozenxid)))
     {
         pgcform->relfrozenxid = frozenxid;
         dirty = true;
     }
 
     /* Similarly for relminmxid */
     if (MultiXactIdIsValid(minmulti) &&
         pgcform->relminmxid != minmulti &&
         (MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
          MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
     {
         pgcform->relminmxid = minmulti;
         dirty = true;
     }
 
     /* If anything changed, write out the tuple. */
     if (dirty)
         heap_inplace_update(rd, ctup);
 
     heap_close(rd, RowExclusiveLock);
 }

void vacuum	(	int	options,
		RangeVar *	relation,
		Oid	relid,
		VacuumParams *	params,
		List *	va_cols,
		BufferAccessStrategy	bstrategy,
		bool	isTopLevel
	)

Definition at line 149 of file vacuum.c.

References ActiveSnapshotSet(), ALLOCSET_DEFAULT_SIZES, AllocSetContextCreate(), analyze_rel(), Assert, BAS_VACUUM, CommitTransactionCommand(), cur, ereport, errcode(), errmsg(), ERROR, get_rel_oids(), GetAccessStrategy(), GetTransactionSnapshot(), IsAutoVacuumWorkerProcess(), IsInTransactionChain(), lfirst_oid, list_length(), MemoryContextDelete(), MemoryContextSwitchTo(), PG_CATCH, PG_END_TRY, PG_RE_THROW, PG_TRY, pgstat_vacuum_stat(), PopActiveSnapshot(), PortalContext, PreventTransactionChain(), PushActiveSnapshot(), StartTransactionCommand(), vac_update_datfrozenxid(), VACOPT_ANALYZE, VACOPT_DISABLE_PAGE_SKIPPING, VACOPT_FULL, VACOPT_VACUUM, vacuum_rel(), VacuumCostActive, VacuumCostBalance, VacuumCostDelay, VacuumPageDirty, VacuumPageHit, and VacuumPageMiss.

Referenced by autovacuum_do_vac_analyze(), and ExecVacuum().

 {
     const char *stmttype;
     volatile bool in_outer_xact,
                 use_own_xacts;
     List       *relations;
     static bool in_vacuum = false;
 
     Assert(params != NULL);
 
     stmttype = (options & VACOPT_VACUUM) ? "VACUUM" : "ANALYZE";
 
     /*
      * We cannot run VACUUM inside a user transaction block; if we were inside
      * a transaction, then our commit- and start-transaction-command calls
      * would not have the intended effect!  There are numerous other subtle
      * dependencies on this, too.
      *
      * ANALYZE (without VACUUM) can run either way.
      */
     if (options & VACOPT_VACUUM)
     {
         PreventTransactionChain(isTopLevel, stmttype);
         in_outer_xact = false;
     }
     else
         in_outer_xact = IsInTransactionChain(isTopLevel);
 
     /*
      * Due to static variables vac_context, anl_context and vac_strategy,
      * vacuum() is not reentrant.  This matters when VACUUM FULL or ANALYZE
      * calls a hostile index expression that itself calls ANALYZE.
      */
     if (in_vacuum)
         ereport(ERROR,
                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                  errmsg("%s cannot be executed from VACUUM or ANALYZE",
                         stmttype)));
 
     /*
      * Sanity check DISABLE_PAGE_SKIPPING option.
      */
     if ((options & VACOPT_FULL) != 0 &&
         (options & VACOPT_DISABLE_PAGE_SKIPPING) != 0)
         ereport(ERROR,
                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                  errmsg("VACUUM option DISABLE_PAGE_SKIPPING cannot be used with FULL")));
 
     /*
      * Send info about dead objects to the statistics collector, unless we are
      * in autovacuum --- autovacuum.c does this for itself.
      */
     if ((options & VACOPT_VACUUM) && !IsAutoVacuumWorkerProcess())
         pgstat_vacuum_stat();
 
     /*
      * Create special memory context for cross-transaction storage.
      *
      * Since it is a child of PortalContext, it will go away eventually even
      * if we suffer an error; there's no need for special abort cleanup logic.
      */
     vac_context = AllocSetContextCreate(PortalContext,
                                         "Vacuum",
                                         ALLOCSET_DEFAULT_SIZES);
 
     /*
      * If caller didn't give us a buffer strategy object, make one in the
      * cross-transaction memory context.
      */
     if (bstrategy == NULL)
     {
         MemoryContext old_context = MemoryContextSwitchTo(vac_context);
 
         bstrategy = GetAccessStrategy(BAS_VACUUM);
         MemoryContextSwitchTo(old_context);
     }
     vac_strategy = bstrategy;
 
     /*
      * Build list of relations to process, unless caller gave us one. (If we
      * build one, we put it in vac_context for safekeeping.)
      */
     relations = get_rel_oids(relid, relation);
 
     /*
      * Decide whether we need to start/commit our own transactions.
      *
      * For VACUUM (with or without ANALYZE): always do so, so that we can
      * release locks as soon as possible.  (We could possibly use the outer
      * transaction for a one-table VACUUM, but handling TOAST tables would be
      * problematic.)
      *
      * For ANALYZE (no VACUUM): if inside a transaction block, we cannot
      * start/commit our own transactions.  Also, there's no need to do so if
      * only processing one relation.  For multiple relations when not within a
      * transaction block, and also in an autovacuum worker, use own
      * transactions so we can release locks sooner.
      */
     if (options & VACOPT_VACUUM)
         use_own_xacts = true;
     else
     {
         Assert(options & VACOPT_ANALYZE);
         if (IsAutoVacuumWorkerProcess())
             use_own_xacts = true;
         else if (in_outer_xact)
             use_own_xacts = false;
         else if (list_length(relations) > 1)
             use_own_xacts = true;
         else
             use_own_xacts = false;
     }
 
     /*
      * vacuum_rel expects to be entered with no transaction active; it will
      * start and commit its own transaction.  But we are called by an SQL
      * command, and so we are executing inside a transaction already. We
      * commit the transaction started in PostgresMain() here, and start
      * another one before exiting to match the commit waiting for us back in
      * PostgresMain().
      */
     if (use_own_xacts)
     {
         Assert(!in_outer_xact);
 
         /* ActiveSnapshot is not set by autovacuum */
         if (ActiveSnapshotSet())
             PopActiveSnapshot();
 
         /* matches the StartTransaction in PostgresMain() */
         CommitTransactionCommand();
     }
 
     /* Turn vacuum cost accounting on or off */
     PG_TRY();
     {
         ListCell   *cur;
 
         in_vacuum = true;
         VacuumCostActive = (VacuumCostDelay > 0);
         VacuumCostBalance = 0;
         VacuumPageHit = 0;
         VacuumPageMiss = 0;
         VacuumPageDirty = 0;
 
         /*
          * Loop to process each selected relation.
          */
         foreach(cur, relations)
         {
             Oid         relid = lfirst_oid(cur);
 
             if (options & VACOPT_VACUUM)
             {
                 if (!vacuum_rel(relid, relation, options, params))
                     continue;
             }
 
             if (options & VACOPT_ANALYZE)
             {
                 /*
                  * If using separate xacts, start one for analyze. Otherwise,
                  * we can use the outer transaction.
                  */
                 if (use_own_xacts)
                 {
                     StartTransactionCommand();
                     /* functions in indexes may want a snapshot set */
                     PushActiveSnapshot(GetTransactionSnapshot());
                 }
 
                 analyze_rel(relid, relation, options, params,
                             va_cols, in_outer_xact, vac_strategy);
 
                 if (use_own_xacts)
                 {
                     PopActiveSnapshot();
                     CommitTransactionCommand();
                 }
             }
         }
     }
     PG_CATCH();
     {
         in_vacuum = false;
         VacuumCostActive = false;
         PG_RE_THROW();
     }
     PG_END_TRY();
 
     in_vacuum = false;
     VacuumCostActive = false;
 
     /*
      * Finish up processing.
      */
     if (use_own_xacts)
     {
         /* here, we are not in a transaction */
 
         /*
          * This matches the CommitTransaction waiting for us in
          * PostgresMain().
          */
         StartTransactionCommand();
     }
 
     if ((options & VACOPT_VACUUM) && !IsAutoVacuumWorkerProcess())
     {
         /*
          * Update pg_database.datfrozenxid, and truncate pg_xact if possible.
          * (autovacuum.c does this for itself.)
          */
         vac_update_datfrozenxid();
     }
 
     /*
      * Clean up working storage --- note we must do this after
      * StartTransactionCommand, else we might be trying to delete the active
      * context!
      */
     MemoryContextDelete(vac_context);
     vac_context = NULL;
 }

void vacuum_delay_point ( void )

Definition at line 1560 of file vacuum.c.

References AutoVacuumUpdateDelay(), CHECK_FOR_INTERRUPTS, InterruptPending, pg_usleep(), VacuumCostActive, VacuumCostBalance, VacuumCostDelay, and VacuumCostLimit.

Referenced by acquire_sample_rows(), blbulkdelete(), blvacuumcleanup(), btvacuumpage(), compute_array_stats(), compute_distinct_stats(), compute_index_stats(), compute_range_stats(), compute_scalar_stats(), compute_trivial_stats(), compute_tsvector_stats(), file_acquire_sample_rows(), ginbulkdelete(), ginInsertCleanup(), ginvacuumcleanup(), ginVacuumPostingTreeLeaves(), gistbulkdelete(), gistvacuumcleanup(), hashbucketcleanup(), lazy_scan_heap(), lazy_vacuum_heap(), spgprocesspending(), and spgvacuumpage().

 {
     /* Always check for interrupts */
     CHECK_FOR_INTERRUPTS();
 
     /* Nap if appropriate */
     if (VacuumCostActive && !InterruptPending &&
         VacuumCostBalance >= VacuumCostLimit)
     {
         int         msec;
 
         msec = VacuumCostDelay * VacuumCostBalance / VacuumCostLimit;
         if (msec > VacuumCostDelay * 4)
             msec = VacuumCostDelay * 4;
 
         pg_usleep(msec * 1000L);
 
         VacuumCostBalance = 0;
 
         /* update balance values for workers */
         AutoVacuumUpdateDelay();
 
         /* Might have gotten an interrupt while sleeping */
         CHECK_FOR_INTERRUPTS();
     }
 }

static bool vacuum_rel	(	Oid	relid,
		RangeVar *	relation,
		int	options,
		VacuumParams *	params
	)

static

Definition at line 1224 of file vacuum.c.

References AccessExclusiveLock, Assert, AtEOXact_GUC(), CHECK_FOR_INTERRUPTS, cluster_rel(), CommitTransactionCommand(), ConditionalLockRelationOid(), ereport, errcode(), errmsg(), GetTransactionSnapshot(), GetUserId(), GetUserIdAndSecContext(), InvalidOid, VacuumParams::is_wraparound, IsAutoVacuumWorkerProcess(), lazy_vacuum_rel(), LockRelationIdForSession(), LockInfoData::lockRelId, LOG, VacuumParams::log_min_duration, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MyDatabaseId, MyPgXact, NewGUCNestLevel(), NoLock, PG_CATALOG_NAMESPACE, pg_class_ownercheck(), pg_database_ownercheck(), PopActiveSnapshot(), PROC_IN_VACUUM, PROC_VACUUM_FOR_WRAPAROUND, PushActiveSnapshot(), RelationData::rd_lockInfo, RelationData::rd_rel, relation_close(), RELATION_IS_OTHER_TEMP, RelationGetRelationName, RelationGetRelid, RELKIND_MATVIEW, RELKIND_PARTITIONED_TABLE, RELKIND_RELATION, RELKIND_TOASTVALUE, RangeVar::relname, SECURITY_RESTRICTED_OPERATION, SetUserIdAndSecContext(), ShareUpdateExclusiveLock, StartTransactionCommand(), try_relation_open(), UnlockRelationIdForSession(), VACOPT_FULL, VACOPT_NOWAIT, VACOPT_SKIPTOAST, VACOPT_VERBOSE, PGXACT::vacuumFlags, and WARNING.

Referenced by vacuum().

 {
     LOCKMODE    lmode;
     Relation    onerel;
     LockRelId   onerelid;
     Oid         toast_relid;
     Oid         save_userid;
     int         save_sec_context;
     int         save_nestlevel;
 
     Assert(params != NULL);
 
     /* Begin a transaction for vacuuming this relation */
     StartTransactionCommand();
 
     /*
      * Functions in indexes may want a snapshot set.  Also, setting a snapshot
      * ensures that RecentGlobalXmin is kept truly recent.
      */
     PushActiveSnapshot(GetTransactionSnapshot());
 
     if (!(options & VACOPT_FULL))
     {
         /*
          * In lazy vacuum, we can set the PROC_IN_VACUUM flag, which lets
          * other concurrent VACUUMs know that they can ignore this one while
          * determining their OldestXmin.  (The reason we don't set it during a
          * full VACUUM is exactly that we may have to run user-defined
          * functions for functional indexes, and we want to make sure that if
          * they use the snapshot set above, any tuples it requires can't get
          * removed from other tables.  An index function that depends on the
          * contents of other tables is arguably broken, but we won't break it
          * here by violating transaction semantics.)
          *
          * We also set the VACUUM_FOR_WRAPAROUND flag, which is passed down by
          * autovacuum; it's used to avoid canceling a vacuum that was invoked
          * in an emergency.
          *
          * Note: these flags remain set until CommitTransaction or
          * AbortTransaction.  We don't want to clear them until we reset
          * MyPgXact->xid/xmin, else OldestXmin might appear to go backwards,
          * which is probably Not Good.
          */
         LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
         MyPgXact->vacuumFlags |= PROC_IN_VACUUM;
         if (params->is_wraparound)
             MyPgXact->vacuumFlags |= PROC_VACUUM_FOR_WRAPAROUND;
         LWLockRelease(ProcArrayLock);
     }
 
     /*
      * Check for user-requested abort.  Note we want this to be inside a
      * transaction, so xact.c doesn't issue useless WARNING.
      */
     CHECK_FOR_INTERRUPTS();
 
     /*
      * Determine the type of lock we want --- hard exclusive lock for a FULL
      * vacuum, but just ShareUpdateExclusiveLock for concurrent vacuum. Either
      * way, we can be sure that no other backend is vacuuming the same table.
      */
     lmode = (options & VACOPT_FULL) ? AccessExclusiveLock : ShareUpdateExclusiveLock;
 
     /*
      * Open the relation and get the appropriate lock on it.
      *
      * There's a race condition here: the rel may have gone away since the
      * last time we saw it.  If so, we don't need to vacuum it.
      *
      * If we've been asked not to wait for the relation lock, acquire it first
      * in non-blocking mode, before calling try_relation_open().
      */
     if (!(options & VACOPT_NOWAIT))
         onerel = try_relation_open(relid, lmode);
     else if (ConditionalLockRelationOid(relid, lmode))
         onerel = try_relation_open(relid, NoLock);
     else
     {
         onerel = NULL;
         if (IsAutoVacuumWorkerProcess() && params->log_min_duration >= 0)
             ereport(LOG,
                     (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
                      errmsg("skipping vacuum of \"%s\" --- lock not available",
                             relation->relname)));
     }
 
     if (!onerel)
     {
         PopActiveSnapshot();
         CommitTransactionCommand();
         return false;
     }
 
     /*
      * Check permissions.
      *
      * We allow the user to vacuum a table if he is superuser, the table
      * owner, or the database owner (but in the latter case, only if it's not
      * a shared relation).  pg_class_ownercheck includes the superuser case.
      *
      * Note we choose to treat permissions failure as a WARNING and keep
      * trying to vacuum the rest of the DB --- is this appropriate?
      */
     if (!(pg_class_ownercheck(RelationGetRelid(onerel), GetUserId()) ||
           (pg_database_ownercheck(MyDatabaseId, GetUserId()) && !onerel->rd_rel->relisshared)))
     {
         if (onerel->rd_rel->relisshared)
             ereport(WARNING,
                     (errmsg("skipping \"%s\" --- only superuser can vacuum it",
                             RelationGetRelationName(onerel))));
         else if (onerel->rd_rel->relnamespace == PG_CATALOG_NAMESPACE)
             ereport(WARNING,
                     (errmsg("skipping \"%s\" --- only superuser or database owner can vacuum it",
                             RelationGetRelationName(onerel))));
         else
             ereport(WARNING,
                     (errmsg("skipping \"%s\" --- only table or database owner can vacuum it",
                             RelationGetRelationName(onerel))));
         relation_close(onerel, lmode);
         PopActiveSnapshot();
         CommitTransactionCommand();
         return false;
     }
 
     /*
      * Check that it's a vacuumable relation; we used to do this in
      * get_rel_oids() but seems safer to check after we've locked the
      * relation.
      */
     if (onerel->rd_rel->relkind != RELKIND_RELATION &&
         onerel->rd_rel->relkind != RELKIND_MATVIEW &&
         onerel->rd_rel->relkind != RELKIND_TOASTVALUE &&
         onerel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
     {
         ereport(WARNING,
                 (errmsg("skipping \"%s\" --- cannot vacuum non-tables or special system tables",
                         RelationGetRelationName(onerel))));
         relation_close(onerel, lmode);
         PopActiveSnapshot();
         CommitTransactionCommand();
         return false;
     }
 
     /*
      * Silently ignore tables that are temp tables of other backends ---
      * trying to vacuum these will lead to great unhappiness, since their
      * contents are probably not up-to-date on disk.  (We don't throw a
      * warning here; it would just lead to chatter during a database-wide
      * VACUUM.)
      */
     if (RELATION_IS_OTHER_TEMP(onerel))
     {
         relation_close(onerel, lmode);
         PopActiveSnapshot();
         CommitTransactionCommand();
         return false;
     }
 
     /*
      * Ignore partitioned tables as there is no work to be done.  Since we
      * release the lock here, it's possible that any partitions added from
      * this point on will not get processed, but that seems harmless.
      */
     if (onerel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
     {
         relation_close(onerel, lmode);
         PopActiveSnapshot();
         CommitTransactionCommand();
 
         /* It's OK for other commands to look at this table */
         return true;
     }
 
     /*
      * Get a session-level lock too. This will protect our access to the
      * relation across multiple transactions, so that we can vacuum the
      * relation's TOAST table (if any) secure in the knowledge that no one is
      * deleting the parent relation.
      *
      * NOTE: this cannot block, even if someone else is waiting for access,
      * because the lock manager knows that both lock requests are from the
      * same process.
      */
     onerelid = onerel->rd_lockInfo.lockRelId;
     LockRelationIdForSession(&onerelid, lmode);
 
     /*
      * Remember the relation's TOAST relation for later, if the caller asked
      * us to process it.  In VACUUM FULL, though, the toast table is
      * automatically rebuilt by cluster_rel so we shouldn't recurse to it.
      */
     if (!(options & VACOPT_SKIPTOAST) && !(options & VACOPT_FULL))
         toast_relid = onerel->rd_rel->reltoastrelid;
     else
         toast_relid = InvalidOid;
 
     /*
      * Switch to the table owner's userid, so that any index functions are run
      * as that user.  Also lock down security-restricted operations and
      * arrange to make GUC variable changes local to this command. (This is
      * unnecessary, but harmless, for lazy VACUUM.)
      */
     GetUserIdAndSecContext(&save_userid, &save_sec_context);
     SetUserIdAndSecContext(onerel->rd_rel->relowner,
                            save_sec_context | SECURITY_RESTRICTED_OPERATION);
     save_nestlevel = NewGUCNestLevel();
 
     /*
      * Do the actual work --- either FULL or "lazy" vacuum
      */
     if (options & VACOPT_FULL)
     {
         /* close relation before vacuuming, but hold lock until commit */
         relation_close(onerel, NoLock);
         onerel = NULL;
 
         /* VACUUM FULL is now a variant of CLUSTER; see cluster.c */
         cluster_rel(relid, InvalidOid, false,
                     (options & VACOPT_VERBOSE) != 0);
     }
     else
         lazy_vacuum_rel(onerel, options, params, vac_strategy);
 
     /* Roll back any GUC changes executed by index functions */
     AtEOXact_GUC(false, save_nestlevel);
 
     /* Restore userid and security context */
     SetUserIdAndSecContext(save_userid, save_sec_context);
 
     /* all done with this class, but hold lock until commit */
     if (onerel)
         relation_close(onerel, NoLock);
 
     /*
      * Complete the transaction and free all temporary memory used.
      */
     PopActiveSnapshot();
     CommitTransactionCommand();
 
     /*
      * If the relation has a secondary toast rel, vacuum that too while we
      * still hold the session lock on the master table.  Note however that
      * "analyze" will not get done on the toast table.  This is good, because
      * the toaster always uses hardcoded index access and statistics are
      * totally unimportant for toast relations.
      */
     if (toast_relid != InvalidOid)
         vacuum_rel(toast_relid, relation, options, params);
 
     /*
      * Now release the session-level lock on the master table.
      */
     UnlockRelationIdForSession(&onerelid, lmode);
 
     /* Report that we really did it. */
     return true;
 }

void vacuum_set_xid_limits	(	Relation	rel,
		int	freeze_min_age,
		int	freeze_table_age,
		int	multixact_freeze_min_age,
		int	multixact_freeze_table_age,
		TransactionId *	oldestXmin,
		TransactionId *	freezeLimit,
		TransactionId *	xidFullScanLimit,
		MultiXactId *	multiXactCutoff,
		MultiXactId *	mxactFullScanLimit
	)

Definition at line 501 of file vacuum.c.

References Assert, autovacuum_freeze_max_age, ereport, errhint(), errmsg(), FirstMultiXactId, FirstNormalTransactionId, GetOldestMultiXactId(), GetOldestXmin(), Min, MultiXactIdPrecedes(), MultiXactMemberFreezeThreshold(), PROCARRAY_FLAGS_VACUUM, ReadNewTransactionId(), ReadNextMultiXactId(), TransactionIdIsNormal, TransactionIdLimitedForOldSnapshots(), TransactionIdPrecedes(), vacuum_freeze_min_age, vacuum_freeze_table_age, vacuum_multixact_freeze_min_age, vacuum_multixact_freeze_table_age, and WARNING.

Referenced by copy_heap_data(), and lazy_vacuum_rel().

 {
     int         freezemin;
     int         mxid_freezemin;
     int         effective_multixact_freeze_max_age;
     TransactionId limit;
     TransactionId safeLimit;
     MultiXactId mxactLimit;
     MultiXactId safeMxactLimit;
 
     /*
      * We can always ignore processes running lazy vacuum.  This is because we
      * use these values only for deciding which tuples we must keep in the
      * tables.  Since lazy vacuum doesn't write its XID anywhere, it's safe to
      * ignore it.  In theory it could be problematic to ignore lazy vacuums in
      * a full vacuum, but keep in mind that only one vacuum process can be
      * working on a particular table at any time, and that each vacuum is
      * always an independent transaction.
      */
     *oldestXmin =
         TransactionIdLimitedForOldSnapshots(GetOldestXmin(rel, PROCARRAY_FLAGS_VACUUM), rel);
 
     Assert(TransactionIdIsNormal(*oldestXmin));
 
     /*
      * Determine the minimum freeze age to use: as specified by the caller, or
      * vacuum_freeze_min_age, but in any case not more than half
      * autovacuum_freeze_max_age, so that autovacuums to prevent XID
      * wraparound won't occur too frequently.
      */
     freezemin = freeze_min_age;
     if (freezemin < 0)
         freezemin = vacuum_freeze_min_age;
     freezemin = Min(freezemin, autovacuum_freeze_max_age / 2);
     Assert(freezemin >= 0);
 
     /*
      * Compute the cutoff XID, being careful not to generate a "permanent" XID
      */
     limit = *oldestXmin - freezemin;
     if (!TransactionIdIsNormal(limit))
         limit = FirstNormalTransactionId;
 
     /*
      * If oldestXmin is very far back (in practice, more than
      * autovacuum_freeze_max_age / 2 XIDs old), complain and force a minimum
      * freeze age of zero.
      */
     safeLimit = ReadNewTransactionId() - autovacuum_freeze_max_age;
     if (!TransactionIdIsNormal(safeLimit))
         safeLimit = FirstNormalTransactionId;
 
     if (TransactionIdPrecedes(limit, safeLimit))
     {
         ereport(WARNING,
                 (errmsg("oldest xmin is far in the past"),
                  errhint("Close open transactions soon to avoid wraparound problems.")));
         limit = *oldestXmin;
     }
 
     *freezeLimit = limit;
 
     /*
      * Compute the multixact age for which freezing is urgent.  This is
      * normally autovacuum_multixact_freeze_max_age, but may be less if we are
      * short of multixact member space.
      */
     effective_multixact_freeze_max_age = MultiXactMemberFreezeThreshold();
 
     /*
      * Determine the minimum multixact freeze age to use: as specified by
      * caller, or vacuum_multixact_freeze_min_age, but in any case not more
      * than half effective_multixact_freeze_max_age, so that autovacuums to
      * prevent MultiXact wraparound won't occur too frequently.
      */
     mxid_freezemin = multixact_freeze_min_age;
     if (mxid_freezemin < 0)
         mxid_freezemin = vacuum_multixact_freeze_min_age;
     mxid_freezemin = Min(mxid_freezemin,
                          effective_multixact_freeze_max_age / 2);
     Assert(mxid_freezemin >= 0);
 
     /* compute the cutoff multi, being careful to generate a valid value */
     mxactLimit = GetOldestMultiXactId() - mxid_freezemin;
     if (mxactLimit < FirstMultiXactId)
         mxactLimit = FirstMultiXactId;
 
     safeMxactLimit =
         ReadNextMultiXactId() - effective_multixact_freeze_max_age;
     if (safeMxactLimit < FirstMultiXactId)
         safeMxactLimit = FirstMultiXactId;
 
     if (MultiXactIdPrecedes(mxactLimit, safeMxactLimit))
     {
         ereport(WARNING,
                 (errmsg("oldest multixact is far in the past"),
                  errhint("Close open transactions with multixacts soon to avoid wraparound problems.")));
         mxactLimit = safeMxactLimit;
     }
 
     *multiXactCutoff = mxactLimit;
 
     if (xidFullScanLimit != NULL)
     {
         int         freezetable;
 
         Assert(mxactFullScanLimit != NULL);
 
         /*
          * Determine the table freeze age to use: as specified by the caller,
          * or vacuum_freeze_table_age, but in any case not more than
          * autovacuum_freeze_max_age * 0.95, so that if you have e.g nightly
          * VACUUM schedule, the nightly VACUUM gets a chance to freeze tuples
          * before anti-wraparound autovacuum is launched.
          */
         freezetable = freeze_table_age;
         if (freezetable < 0)
             freezetable = vacuum_freeze_table_age;
         freezetable = Min(freezetable, autovacuum_freeze_max_age * 0.95);
         Assert(freezetable >= 0);
 
         /*
          * Compute XID limit causing a full-table vacuum, being careful not to
          * generate a "permanent" XID.
          */
         limit = ReadNewTransactionId() - freezetable;
         if (!TransactionIdIsNormal(limit))
             limit = FirstNormalTransactionId;
 
         *xidFullScanLimit = limit;
 
         /*
          * Similar to the above, determine the table freeze age to use for
          * multixacts: as specified by the caller, or
          * vacuum_multixact_freeze_table_age, but in any case not more than
          * autovacuum_multixact_freeze_table_age * 0.95, so that if you have
          * e.g. nightly VACUUM schedule, the nightly VACUUM gets a chance to
          * freeze multixacts before anti-wraparound autovacuum is launched.
          */
         freezetable = multixact_freeze_table_age;
         if (freezetable < 0)
             freezetable = vacuum_multixact_freeze_table_age;
         freezetable = Min(freezetable,
                           effective_multixact_freeze_max_age * 0.95);
         Assert(freezetable >= 0);
 
         /*
          * Compute MultiXact limit causing a full-table vacuum, being careful
          * to generate a valid MultiXact value.
          */
         mxactLimit = ReadNextMultiXactId() - freezetable;
         if (mxactLimit < FirstMultiXactId)
             mxactLimit = FirstMultiXactId;
 
         *mxactFullScanLimit = mxactLimit;
     }
     else
     {
         Assert(mxactFullScanLimit == NULL);
     }
 }