vacuum.h File Reference

#include "access/htup.h"
#include "catalog/pg_statistic.h"
#include "catalog/pg_type.h"
#include "nodes/parsenodes.h"
#include "storage/buf.h"
#include "storage/lock.h"
#include "utils/relcache.h"

Include dependency graph for vacuum.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Data Structures
struct	VacAttrStats
struct	VacuumParams

Typedefs
typedef struct VacAttrStats *	VacAttrStatsP
typedef Datum(*	AnalyzeAttrFetchFunc )(VacAttrStatsP stats, int rownum, bool *isNull)
typedef void(*	AnalyzeAttrComputeStatsFunc )(VacAttrStatsP stats, AnalyzeAttrFetchFunc fetchfunc, int samplerows, double totalrows)
typedef struct VacAttrStats	VacAttrStats
typedef struct VacuumParams	VacuumParams

Functions
void	ExecVacuum (VacuumStmt *vacstmt, bool isTopLevel)
void	vacuum (int options, List *relations, VacuumParams *params, BufferAccessStrategy bstrategy, bool isTopLevel)
void	vac_open_indexes (Relation relation, LOCKMODE lockmode, int *nindexes, Relation **Irel)
void	vac_close_indexes (int nindexes, Relation *Irel, LOCKMODE lockmode)
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	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)
void	vac_update_datfrozenxid (void)
void	vacuum_delay_point (void)
void	lazy_vacuum_rel (Relation onerel, int options, VacuumParams *params, BufferAccessStrategy bstrategy)
void	analyze_rel (Oid relid, RangeVar *relation, int options, VacuumParams *params, List *va_cols, bool in_outer_xact, BufferAccessStrategy bstrategy)
bool	std_typanalyze (VacAttrStats *stats)
double	anl_random_fract (void)
double	anl_init_selection_state (int n)
double	anl_get_next_S (double t, int n, double *stateptr)

Variables
PGDLLIMPORT int	default_statistics_target
int	vacuum_freeze_min_age
int	vacuum_freeze_table_age
int	vacuum_multixact_freeze_min_age
int	vacuum_multixact_freeze_table_age

Typedef Documentation

typedef void(* AnalyzeAttrComputeStatsFunc)(VacAttrStatsP stats, AnalyzeAttrFetchFunc fetchfunc, int samplerows, double totalrows)

Definition at line 64 of file vacuum.h.

typedef Datum(* AnalyzeAttrFetchFunc)(VacAttrStatsP stats, int rownum, bool *isNull)

Definition at line 61 of file vacuum.h.

typedef struct VacAttrStats VacAttrStats

typedef struct VacAttrStats* VacAttrStatsP

Definition at line 59 of file vacuum.h.

typedef struct VacuumParams VacuumParams

Function Documentation

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

Definition at line 115 of file analyze.c.

References acquire_sample_rows(), FdwRoutine::AnalyzeForeignTable, CHECK_FOR_INTERRUPTS, ConditionalLockRelationOid(), DEBUG2, do_analyze_rel(), elevel, ereport, errcode(), errmsg(), GetFdwRoutineForRelation(), GetUserId(), INFO, IsAutoVacuumWorkerProcess(), LOG, VacuumParams::log_min_duration, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MyDatabaseId, MyPgXact, NoLock, PG_CATALOG_NAMESPACE, pg_class_ownercheck(), pg_database_ownercheck(), PROC_IN_ANALYZE, RelationData::rd_rel, relation_close(), RELATION_IS_OTHER_TEMP, RelationGetNumberOfBlocks, RelationGetRelationName, RelationGetRelid, RELKIND_FOREIGN_TABLE, RELKIND_MATVIEW, RELKIND_PARTITIONED_TABLE, RELKIND_RELATION, RangeVar::relname, ShareUpdateExclusiveLock, StatisticRelationId, try_relation_open(), VACOPT_NOWAIT, VACOPT_VACUUM, VACOPT_VERBOSE, PGXACT::vacuumFlags, and WARNING.

Referenced by vacuum().

{
    Relation    onerel;
    int         elevel;
    AcquireSampleRowsFunc acquirefunc = NULL;
    BlockNumber relpages = 0;

    /* Select logging level */
    if (options & VACOPT_VERBOSE)
        elevel = INFO;
    else
        elevel = DEBUG2;

    /* Set up static variables */
    vac_strategy = bstrategy;

    /*
     * Check for user-requested abort.
     */
    CHECK_FOR_INTERRUPTS();

    /*
     * Open the relation, getting ShareUpdateExclusiveLock to ensure that two
     * ANALYZEs don't run on it concurrently.  (This also locks out a
     * concurrent VACUUM, which doesn't matter much at the moment but might
     * matter if we ever try to accumulate stats on dead tuples.) If the rel
     * has been dropped since we last saw it, we don't need to process it.
     */
    if (!(options & VACOPT_NOWAIT))
        onerel = try_relation_open(relid, ShareUpdateExclusiveLock);
    else if (ConditionalLockRelationOid(relid, ShareUpdateExclusiveLock))
        onerel = try_relation_open(relid, NoLock);
    else
    {
        onerel = NULL;
        if (relation &&
            IsAutoVacuumWorkerProcess() && params->log_min_duration >= 0)
            ereport(LOG,
                    (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
                     errmsg("skipping analyze of \"%s\" --- lock not available",
                            relation->relname)));
    }
    if (!onerel)
        return;

    /*
     * Check permissions --- this should match vacuum's check!
     */
    if (!(pg_class_ownercheck(RelationGetRelid(onerel), GetUserId()) ||
          (pg_database_ownercheck(MyDatabaseId, GetUserId()) && !onerel->rd_rel->relisshared)))
    {
        /* No need for a WARNING if we already complained during VACUUM */
        if (!(options & VACOPT_VACUUM))
        {
            if (onerel->rd_rel->relisshared)
                ereport(WARNING,
                        (errmsg("skipping \"%s\" --- only superuser can analyze it",
                                RelationGetRelationName(onerel))));
            else if (onerel->rd_rel->relnamespace == PG_CATALOG_NAMESPACE)
                ereport(WARNING,
                        (errmsg("skipping \"%s\" --- only superuser or database owner can analyze it",
                                RelationGetRelationName(onerel))));
            else
                ereport(WARNING,
                        (errmsg("skipping \"%s\" --- only table or database owner can analyze it",
                                RelationGetRelationName(onerel))));
        }
        relation_close(onerel, ShareUpdateExclusiveLock);
        return;
    }

    /*
     * Silently ignore tables that are temp tables of other backends ---
     * trying to analyze these is rather pointless, 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 ANALYZE.)
     */
    if (RELATION_IS_OTHER_TEMP(onerel))
    {
        relation_close(onerel, ShareUpdateExclusiveLock);
        return;
    }

    /*
     * We can ANALYZE any table except pg_statistic. See update_attstats
     */
    if (RelationGetRelid(onerel) == StatisticRelationId)
    {
        relation_close(onerel, ShareUpdateExclusiveLock);
        return;
    }

    /*
     * Check that it's of an analyzable relkind, and set up appropriately.
     */
    if (onerel->rd_rel->relkind == RELKIND_RELATION ||
        onerel->rd_rel->relkind == RELKIND_MATVIEW)
    {
        /* Regular table, so we'll use the regular row acquisition function */
        acquirefunc = acquire_sample_rows;
        /* Also get regular table's size */
        relpages = RelationGetNumberOfBlocks(onerel);
    }
    else if (onerel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
    {
        /*
         * For a foreign table, call the FDW's hook function to see whether it
         * supports analysis.
         */
        FdwRoutine *fdwroutine;
        bool        ok = false;

        fdwroutine = GetFdwRoutineForRelation(onerel, false);

        if (fdwroutine->AnalyzeForeignTable != NULL)
            ok = fdwroutine->AnalyzeForeignTable(onerel,
                                                 &acquirefunc,
                                                 &relpages);

        if (!ok)
        {
            ereport(WARNING,
                    (errmsg("skipping \"%s\" --- cannot analyze this foreign table",
                            RelationGetRelationName(onerel))));
            relation_close(onerel, ShareUpdateExclusiveLock);
            return;
        }
    }
    else if (onerel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
    {
        /*
         * For partitioned tables, we want to do the recursive ANALYZE below.
         */
    }
    else
    {
        /* No need for a WARNING if we already complained during VACUUM */
        if (!(options & VACOPT_VACUUM))
            ereport(WARNING,
                    (errmsg("skipping \"%s\" --- cannot analyze non-tables or special system tables",
                            RelationGetRelationName(onerel))));
        relation_close(onerel, ShareUpdateExclusiveLock);
        return;
    }

    /*
     * OK, let's do it.  First let other backends know I'm in ANALYZE.
     */
    LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
    MyPgXact->vacuumFlags |= PROC_IN_ANALYZE;
    LWLockRelease(ProcArrayLock);

    /*
     * Do the normal non-recursive ANALYZE.  We can skip this for partitioned
     * tables, which don't contain any rows.
     */
    if (onerel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
        do_analyze_rel(onerel, options, params, va_cols, acquirefunc,
                       relpages, false, in_outer_xact, elevel);

    /*
     * If there are child tables, do recursive ANALYZE.
     */
    if (onerel->rd_rel->relhassubclass)
        do_analyze_rel(onerel, options, params, va_cols, acquirefunc, relpages,
                       true, in_outer_xact, elevel);

    /*
     * Close source relation now, but keep lock so that no one deletes it
     * before we commit.  (If someone did, they'd fail to clean up the entries
     * we made in pg_statistic.  Also, releasing the lock before commit would
     * expose us to concurrent-update failures in update_attstats.)
     */
    relation_close(onerel, NoLock);

    /*
     * Reset my PGXACT flag.  Note: we need this here, and not in vacuum_rel,
     * because the vacuum flag is cleared by the end-of-xact code.
     */
    LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
    MyPgXact->vacuumFlags &= ~PROC_IN_ANALYZE;
    LWLockRelease(ProcArrayLock);
}

double anl_get_next_S	(	double	t,
		int	n,
		double *	stateptr
	)

Definition at line 284 of file sampling.c.

{
    double      result;

    oldrs.W = *stateptr;
    result = reservoir_get_next_S(&oldrs, t, n);
    *stateptr = oldrs.W;
    return result;
}

double anl_init_selection_state

(

int

n

)

Definition at line 273 of file sampling.c.

{
    /* initialize if first time through */
    if (oldrs.randstate[0] == 0)
        sampler_random_init_state(random(), oldrs.randstate);

    /* Initial value of W (for use when Algorithm Z is first applied) */
    return exp(-log(sampler_random_fract(oldrs.randstate)) / n);
}

double anl_random_fract

(

void

)

Definition at line 262 of file sampling.c.

{
    /* initialize if first time through */
    if (oldrs.randstate[0] == 0)
        sampler_random_init_state(random(), oldrs.randstate);

    /* and compute a random fraction */
    return sampler_random_fract(oldrs.randstate);
}

void ExecVacuum	(	VacuumStmt *	vacstmt,
		bool	isTopLevel
	)

Definition at line 87 of file vacuum.c.

References Assert, ereport, errcode(), errmsg(), ERROR, VacuumParams::freeze_min_age, VacuumParams::freeze_table_age, VacuumParams::is_wraparound, lfirst_node, VacuumParams::log_min_duration, VacuumParams::multixact_freeze_min_age, VacuumParams::multixact_freeze_table_age, NIL, VacuumStmt::options, VacuumStmt::rels, VacuumRelation::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_SKIPTOAST));

    /*
     * Make sure VACOPT_ANALYZE is specified if any column lists are present.
     */
    if (!(vacstmt->options & VACOPT_ANALYZE))
    {
        ListCell   *lc;

        foreach(lc, vacstmt->rels)
        {
            VacuumRelation *vrel = lfirst_node(VacuumRelation, lc);

            if (vrel->va_cols != NIL)
                ereport(ERROR,
                        (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                         errmsg("ANALYZE option must be specified when a column list is provided")));
        }
    }

    /*
     * 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->rels, &params, NULL, isTopLevel);
}

void lazy_vacuum_rel	(	Relation	onerel,
		int	options,
		VacuumParams *	params,
		BufferAccessStrategy	bstrategy
	)

Definition at line 182 of file vacuumlazy.c.

References _, appendStringInfo(), Assert, buf, StringInfoData::data, DEBUG2, elevel, ereport, errmsg_internal(), FreeSpaceMapVacuum(), VacuumParams::freeze_min_age, VacuumParams::freeze_table_age, FreezeLimit, LVRelStats::frozenskipped_pages, get_database_name(), get_namespace_name(), GetCurrentTimestamp(), LVRelStats::hasindex, INFO, initStringInfo(), InvalidMultiXactId, InvalidTransactionId, IsAutoVacuumWorkerProcess(), lazy_scan_heap(), lazy_truncate_heap(), LVRelStats::lock_waiter_detected, LOG, VacuumParams::log_min_duration, VacuumParams::multixact_freeze_min_age, VacuumParams::multixact_freeze_table_age, MultiXactCutoff, MultiXactIdPrecedesOrEquals(), MyDatabaseId, LVRelStats::new_dead_tuples, LVRelStats::new_rel_tuples, NoLock, LVRelStats::num_index_scans, LVRelStats::old_rel_pages, LVRelStats::old_rel_tuples, OldestXmin, LVRelStats::pages_removed, palloc0(), pfree(), pg_rusage_init(), pg_rusage_show(), pgstat_progress_end_command(), pgstat_progress_start_command(), pgstat_progress_update_param(), pgstat_report_vacuum(), LVRelStats::pinskipped_pages, PROGRESS_COMMAND_VACUUM, PROGRESS_VACUUM_PHASE, PROGRESS_VACUUM_PHASE_FINAL_CLEANUP, RelationData::rd_rel, LVRelStats::rel_pages, RelationGetNamespace, RelationGetRelationName, RelationGetRelid, RowExclusiveLock, LVRelStats::scanned_pages, should_attempt_truncation(), TimestampDifference(), TimestampDifferenceExceeds(), TransactionIdPrecedesOrEquals(), LVRelStats::tupcount_pages, LVRelStats::tuples_deleted, vac_close_indexes(), vac_open_indexes(), vac_update_relstats(), VACOPT_DISABLE_PAGE_SKIPPING, VACOPT_VERBOSE, vacuum_set_xid_limits(), VacuumPageDirty, VacuumPageHit, VacuumPageMiss, and visibilitymap_count().

Referenced by vacuum_rel().

{
    LVRelStats *vacrelstats;
    Relation   *Irel;
    int         nindexes;
    PGRUsage    ru0;
    TimestampTz starttime = 0;
    long        secs;
    int         usecs;
    double      read_rate,
                write_rate;
    bool        aggressive;     /* should we scan all unfrozen pages? */
    bool        scanned_all_unfrozen;   /* actually scanned all such pages? */
    TransactionId xidFullScanLimit;
    MultiXactId mxactFullScanLimit;
    BlockNumber new_rel_pages;
    double      new_rel_tuples;
    BlockNumber new_rel_allvisible;
    double      new_live_tuples;
    TransactionId new_frozen_xid;
    MultiXactId new_min_multi;

    Assert(params != NULL);

    /* measure elapsed time iff autovacuum logging requires it */
    if (IsAutoVacuumWorkerProcess() && params->log_min_duration >= 0)
    {
        pg_rusage_init(&ru0);
        starttime = GetCurrentTimestamp();
    }

    if (options & VACOPT_VERBOSE)
        elevel = INFO;
    else
        elevel = DEBUG2;

    pgstat_progress_start_command(PROGRESS_COMMAND_VACUUM,
                                  RelationGetRelid(onerel));

    vac_strategy = bstrategy;

    vacuum_set_xid_limits(onerel,
                          params->freeze_min_age,
                          params->freeze_table_age,
                          params->multixact_freeze_min_age,
                          params->multixact_freeze_table_age,
                          &OldestXmin, &FreezeLimit, &xidFullScanLimit,
                          &MultiXactCutoff, &mxactFullScanLimit);

    /*
     * We request an aggressive scan if the table's frozen Xid is now older
     * than or equal to the requested Xid full-table scan limit; or if the
     * table's minimum MultiXactId is older than or equal to the requested
     * mxid full-table scan limit; or if DISABLE_PAGE_SKIPPING was specified.
     */
    aggressive = TransactionIdPrecedesOrEquals(onerel->rd_rel->relfrozenxid,
                                               xidFullScanLimit);
    aggressive |= MultiXactIdPrecedesOrEquals(onerel->rd_rel->relminmxid,
                                              mxactFullScanLimit);
    if (options & VACOPT_DISABLE_PAGE_SKIPPING)
        aggressive = true;

    vacrelstats = (LVRelStats *) palloc0(sizeof(LVRelStats));

    vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
    vacrelstats->old_rel_tuples = onerel->rd_rel->reltuples;
    vacrelstats->num_index_scans = 0;
    vacrelstats->pages_removed = 0;
    vacrelstats->lock_waiter_detected = false;

    /* Open all indexes of the relation */
    vac_open_indexes(onerel, RowExclusiveLock, &nindexes, &Irel);
    vacrelstats->hasindex = (nindexes > 0);

    /* Do the vacuuming */
    lazy_scan_heap(onerel, options, vacrelstats, Irel, nindexes, aggressive);

    /* Done with indexes */
    vac_close_indexes(nindexes, Irel, NoLock);

    /*
     * Compute whether we actually scanned the all unfrozen pages. If we did,
     * we can adjust relfrozenxid and relminmxid.
     *
     * NB: We need to check this before truncating the relation, because that
     * will change ->rel_pages.
     */
    if ((vacrelstats->scanned_pages + vacrelstats->frozenskipped_pages)
        < vacrelstats->rel_pages)
    {
        Assert(!aggressive);
        scanned_all_unfrozen = false;
    }
    else
        scanned_all_unfrozen = true;

    /*
     * Optionally truncate the relation.
     */
    if (should_attempt_truncation(vacrelstats))
        lazy_truncate_heap(onerel, vacrelstats);

    /* Report that we are now doing final cleanup */
    pgstat_progress_update_param(PROGRESS_VACUUM_PHASE,
                                 PROGRESS_VACUUM_PHASE_FINAL_CLEANUP);

    /* Vacuum the Free Space Map */
    FreeSpaceMapVacuum(onerel);

    /*
     * Update statistics in pg_class.
     *
     * A corner case here is that if we scanned no pages at all because every
     * page is all-visible, we should not update relpages/reltuples, because
     * we have no new information to contribute.  In particular this keeps us
     * from replacing relpages=reltuples=0 (which means "unknown tuple
     * density") with nonzero relpages and reltuples=0 (which means "zero
     * tuple density") unless there's some actual evidence for the latter.
     *
     * It's important that we use tupcount_pages and not scanned_pages for the
     * check described above; scanned_pages counts pages where we could not
     * get cleanup lock, and which were processed only for frozenxid purposes.
     *
     * We do update relallvisible even in the corner case, since if the table
     * is all-visible we'd definitely like to know that.  But clamp the value
     * to be not more than what we're setting relpages to.
     *
     * Also, don't change relfrozenxid/relminmxid if we skipped any pages,
     * since then we don't know for certain that all tuples have a newer xmin.
     */
    new_rel_pages = vacrelstats->rel_pages;
    new_rel_tuples = vacrelstats->new_rel_tuples;
    if (vacrelstats->tupcount_pages == 0 && new_rel_pages > 0)
    {
        new_rel_pages = vacrelstats->old_rel_pages;
        new_rel_tuples = vacrelstats->old_rel_tuples;
    }

    visibilitymap_count(onerel, &new_rel_allvisible, NULL);
    if (new_rel_allvisible > new_rel_pages)
        new_rel_allvisible = new_rel_pages;

    new_frozen_xid = scanned_all_unfrozen ? FreezeLimit : InvalidTransactionId;
    new_min_multi = scanned_all_unfrozen ? MultiXactCutoff : InvalidMultiXactId;

    vac_update_relstats(onerel,
                        new_rel_pages,
                        new_rel_tuples,
                        new_rel_allvisible,
                        vacrelstats->hasindex,
                        new_frozen_xid,
                        new_min_multi,
                        false);

    /* report results to the stats collector, too */
    new_live_tuples = new_rel_tuples - vacrelstats->new_dead_tuples;
    if (new_live_tuples < 0)
        new_live_tuples = 0;    /* just in case */

    pgstat_report_vacuum(RelationGetRelid(onerel),
                         onerel->rd_rel->relisshared,
                         new_live_tuples,
                         vacrelstats->new_dead_tuples);
    pgstat_progress_end_command();

    /* and log the action if appropriate */
    if (IsAutoVacuumWorkerProcess() && params->log_min_duration >= 0)
    {
        TimestampTz endtime = GetCurrentTimestamp();

        if (params->log_min_duration == 0 ||
            TimestampDifferenceExceeds(starttime, endtime,
                                       params->log_min_duration))
        {
            StringInfoData buf;

            TimestampDifference(starttime, endtime, &secs, &usecs);

            read_rate = 0;
            write_rate = 0;
            if ((secs > 0) || (usecs > 0))
            {
                read_rate = (double) BLCKSZ * VacuumPageMiss / (1024 * 1024) /
                    (secs + usecs / 1000000.0);
                write_rate = (double) BLCKSZ * VacuumPageDirty / (1024 * 1024) /
                    (secs + usecs / 1000000.0);
            }

            /*
             * This is pretty messy, but we split it up so that we can skip
             * emitting individual parts of the message when not applicable.
             */
            initStringInfo(&buf);
            appendStringInfo(&buf, _("automatic vacuum of table \"%s.%s.%s\": index scans: %d\n"),
                             get_database_name(MyDatabaseId),
                             get_namespace_name(RelationGetNamespace(onerel)),
                             RelationGetRelationName(onerel),
                             vacrelstats->num_index_scans);
            appendStringInfo(&buf, _("pages: %u removed, %u remain, %u skipped due to pins, %u skipped frozen\n"),
                             vacrelstats->pages_removed,
                             vacrelstats->rel_pages,
                             vacrelstats->pinskipped_pages,
                             vacrelstats->frozenskipped_pages);
            appendStringInfo(&buf,
                             _("tuples: %.0f removed, %.0f remain, %.0f are dead but not yet removable, oldest xmin: %u\n"),
                             vacrelstats->tuples_deleted,
                             vacrelstats->new_rel_tuples,
                             vacrelstats->new_dead_tuples,
                             OldestXmin);
            appendStringInfo(&buf,
                             _("buffer usage: %d hits, %d misses, %d dirtied\n"),
                             VacuumPageHit,
                             VacuumPageMiss,
                             VacuumPageDirty);
            appendStringInfo(&buf, _("avg read rate: %.3f MB/s, avg write rate: %.3f MB/s\n"),
                             read_rate, write_rate);
            appendStringInfo(&buf, _("system usage: %s"), pg_rusage_show(&ru0));

            ereport(LOG,
                    (errmsg_internal("%s", buf.data)));
            pfree(buf.data);
        }
    }
}

bool std_typanalyze

(

VacAttrStats *

stats

)

Definition at line 1739 of file analyze.c.

References VacAttrStats::attr, VacAttrStats::attrtypid, compute_distinct_stats(), compute_scalar_stats(), VacAttrStats::compute_stats, compute_trivial_stats(), default_statistics_target, StdAnalyzeData::eqfunc, StdAnalyzeData::eqopr, VacAttrStats::extra_data, get_opcode(), get_sort_group_operators(), InvalidOid, StdAnalyzeData::ltopr, VacAttrStats::minrows, OidIsValid, and palloc().

Referenced by array_typanalyze(), and examine_attribute().

{
    Form_pg_attribute attr = stats->attr;
    Oid         ltopr;
    Oid         eqopr;
    StdAnalyzeData *mystats;

    /* If the attstattarget column is negative, use the default value */
    /* NB: it is okay to scribble on stats->attr since it's a copy */
    if (attr->attstattarget < 0)
        attr->attstattarget = default_statistics_target;

    /* Look for default "<" and "=" operators for column's type */
    get_sort_group_operators(stats->attrtypid,
                             false, false, false,
                             &ltopr, &eqopr, NULL,
                             NULL);

    /* Save the operator info for compute_stats routines */
    mystats = (StdAnalyzeData *) palloc(sizeof(StdAnalyzeData));
    mystats->eqopr = eqopr;
    mystats->eqfunc = OidIsValid(eqopr) ? get_opcode(eqopr) : InvalidOid;
    mystats->ltopr = ltopr;
    stats->extra_data = mystats;

    /*
     * Determine which standard statistics algorithm to use
     */
    if (OidIsValid(eqopr) && OidIsValid(ltopr))
    {
        /* Seems to be a scalar datatype */
        stats->compute_stats = compute_scalar_stats;
        /*--------------------
         * The following choice of minrows is based on the paper
         * "Random sampling for histogram construction: how much is enough?"
         * by Surajit Chaudhuri, Rajeev Motwani and Vivek Narasayya, in
         * Proceedings of ACM SIGMOD International Conference on Management
         * of Data, 1998, Pages 436-447.  Their Corollary 1 to Theorem 5
         * says that for table size n, histogram size k, maximum relative
         * error in bin size f, and error probability gamma, the minimum
         * random sample size is
         *      r = 4 * k * ln(2*n/gamma) / f^2
         * Taking f = 0.5, gamma = 0.01, n = 10^6 rows, we obtain
         *      r = 305.82 * k
         * Note that because of the log function, the dependence on n is
         * quite weak; even at n = 10^12, a 300*k sample gives <= 0.66
         * bin size error with probability 0.99.  So there's no real need to
         * scale for n, which is a good thing because we don't necessarily
         * know it at this point.
         *--------------------
         */
        stats->minrows = 300 * attr->attstattarget;
    }
    else if (OidIsValid(eqopr))
    {
        /* We can still recognize distinct values */
        stats->compute_stats = compute_distinct_stats;
        /* Might as well use the same minrows as above */
        stats->minrows = 300 * attr->attstattarget;
    }
    else
    {
        /* Can't do much but the trivial stuff */
        stats->compute_stats = compute_trivial_stats;
        /* Might as well use the same minrows as above */
        stats->minrows = 300 * attr->attstattarget;
    }

    return true;
}

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

Definition at line 1637 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 777 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 1594 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);
}

void vac_update_datfrozenxid

(

void

)

Definition at line 1014 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 877 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,
		List *	relations,
		VacuumParams *	params,
		BufferAccessStrategy	bstrategy,
		bool	isTopLevel
	)

Definition at line 166 of file vacuum.c.

References ActiveSnapshotSet(), ALLOCSET_DEFAULT_SIZES, AllocSetContextCreate(), analyze_rel(), Assert, BAS_VACUUM, CommitTransactionCommand(), cur, ereport, errcode(), errmsg(), ERROR, expand_vacuum_rel(), get_all_vacuum_rels(), GetAccessStrategy(), GetTransactionSnapshot(), IsAutoVacuumWorkerProcess(), IsInTransactionChain(), lfirst_node, list_concat(), list_length(), MemoryContextDelete(), MemoryContextSwitchTo(), NIL, VacuumRelation::oid, PG_CATCH, PG_END_TRY, PG_RE_THROW, PG_TRY, pgstat_vacuum_stat(), PopActiveSnapshot(), PortalContext, PreventTransactionChain(), PushActiveSnapshot(), VacuumRelation::relation, StartTransactionCommand(), VacuumRelation::va_cols, 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().

{
    static bool in_vacuum = false;

    const char *stmttype;
    volatile bool in_outer_xact,
                use_own_xacts;

    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 relation(s) to process, putting any new data in
     * vac_context for safekeeping.
     */
    if (relations != NIL)
    {
        List       *newrels = NIL;
        ListCell   *lc;

        foreach(lc, relations)
        {
            VacuumRelation *vrel = lfirst_node(VacuumRelation, lc);
            List       *sublist;
            MemoryContext old_context;

            sublist = expand_vacuum_rel(vrel);
            old_context = MemoryContextSwitchTo(vac_context);
            newrels = list_concat(newrels, sublist);
            MemoryContextSwitchTo(old_context);
        }
        relations = newrels;
    }
    else
        relations = get_all_vacuum_rels();

    /*
     * 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, and set/clear in_vacuum */
    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)
        {
            VacuumRelation *vrel = lfirst_node(VacuumRelation, cur);

            if (options & VACOPT_VACUUM)
            {
                if (!vacuum_rel(vrel->oid, vrel->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(vrel->oid, vrel->relation, options, params,
                            vrel->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 1658 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();
    }
}

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 593 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);
    }
}

Variable Documentation

PGDLLIMPORT int default_statistics_target

Definition at line 77 of file analyze.c.

Referenced by range_typanalyze(), std_typanalyze(), and ts_typanalyze().

int vacuum_freeze_min_age

Definition at line 59 of file vacuum.c.

Referenced by do_autovacuum(), and vacuum_set_xid_limits().

int vacuum_freeze_table_age

Definition at line 60 of file vacuum.c.

Referenced by do_autovacuum(), and vacuum_set_xid_limits().

int vacuum_multixact_freeze_min_age

Definition at line 61 of file vacuum.c.

Referenced by do_autovacuum(), and vacuum_set_xid_limits().

int vacuum_multixact_freeze_table_age

Definition at line 62 of file vacuum.c.

Referenced by do_autovacuum(), and vacuum_set_xid_limits().