vacuum.h File Reference

#include "access/htup.h"
#include "catalog/pg_class.h"
#include "catalog/pg_statistic.h"
#include "catalog/pg_type.h"
#include "parser/parse_node.h"
#include "storage/buf.h"
#include "storage/lock.h"
#include "utils/relcache.h"

Include dependency graph for vacuum.h:

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Data Structures
struct	VacAttrStats
struct	VacuumParams

Macros
#define	VACUUM_OPTION_NO_PARALLEL   0
#define	VACUUM_OPTION_PARALLEL_BULKDEL   (1 << 0)
#define	VACUUM_OPTION_PARALLEL_COND_CLEANUP   (1 << 1)
#define	VACUUM_OPTION_PARALLEL_CLEANUP   (1 << 2)
#define	VACUUM_OPTION_MAX_VALID_VALUE   ((1 << 3) - 1)

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 enum VacuumOption	VacuumOption
typedef enum VacOptTernaryValue	VacOptTernaryValue
typedef struct VacuumParams	VacuumParams

Enumerations
enum	VacuumOption {   VACOPT_VACUUM = 1 << 0, VACOPT_ANALYZE = 1 << 1, VACOPT_VERBOSE = 1 << 2, VACOPT_FREEZE = 1 << 3,   VACOPT_FULL = 1 << 4, VACOPT_SKIP_LOCKED = 1 << 5, VACOPT_SKIPTOAST = 1 << 6, VACOPT_DISABLE_PAGE_SKIPPING = 1 << 7 }
enum	VacOptTernaryValue { VACOPT_TERNARY_DEFAULT = 0, VACOPT_TERNARY_DISABLED, VACOPT_TERNARY_ENABLED }

Functions
void	ExecVacuum (ParseState *pstate, VacuumStmt *vacstmt, bool isTopLevel)
void	vacuum (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, 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)
bool	vacuum_is_relation_owner (Oid relid, Form_pg_class reltuple, int options)
Relation	vacuum_open_relation (Oid relid, RangeVar *relation, int options, bool verbose, LOCKMODE lmode)
void	analyze_rel (Oid relid, RangeVar *relation, 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
pg_atomic_uint32 *	VacuumSharedCostBalance
pg_atomic_uint32 *	VacuumActiveNWorkers
int	VacuumCostBalanceLocal

Macro Definition Documentation

VACUUM_OPTION_MAX_VALID_VALUE

#define VACUUM_OPTION_MAX_VALID_VALUE   ((1 << 3) - 1)

Definition at line 63 of file vacuum.h.

Referenced by begin_parallel_vacuum().

VACUUM_OPTION_NO_PARALLEL

#define VACUUM_OPTION_NO_PARALLEL   0

Definition at line 39 of file vacuum.h.

Referenced by compute_parallel_vacuum_workers(), and dihandler().

VACUUM_OPTION_PARALLEL_BULKDEL

#define VACUUM_OPTION_PARALLEL_BULKDEL   (1 << 0)

Definition at line 45 of file vacuum.h.

Referenced by begin_parallel_vacuum(), blhandler(), bthandler(), compute_parallel_vacuum_workers(), ginhandler(), gisthandler(), hashhandler(), skip_parallel_vacuum_index(), and spghandler().

VACUUM_OPTION_PARALLEL_CLEANUP

#define VACUUM_OPTION_PARALLEL_CLEANUP   (1 << 2)

Definition at line 60 of file vacuum.h.

Referenced by begin_parallel_vacuum(), blhandler(), brinhandler(), compute_parallel_vacuum_workers(), ginhandler(), and skip_parallel_vacuum_index().

VACUUM_OPTION_PARALLEL_COND_CLEANUP

#define VACUUM_OPTION_PARALLEL_COND_CLEANUP   (1 << 1)

Definition at line 52 of file vacuum.h.

Referenced by begin_parallel_vacuum(), bthandler(), compute_parallel_vacuum_workers(), gisthandler(), skip_parallel_vacuum_index(), and spghandler().

Typedef Documentation

AnalyzeAttrComputeStatsFunc

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

Definition at line 105 of file vacuum.h.

AnalyzeAttrFetchFunc

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

Definition at line 102 of file vacuum.h.

VacAttrStats

typedef struct VacAttrStats VacAttrStats

VacAttrStatsP

typedef struct VacAttrStats* VacAttrStatsP

Definition at line 100 of file vacuum.h.

VacOptTernaryValue

typedef enum VacOptTernaryValue VacOptTernaryValue

VacuumOption

typedef enum VacuumOption VacuumOption

VacuumParams

typedef struct VacuumParams VacuumParams

Enumeration Type Documentation

VacOptTernaryValue

enum VacOptTernaryValue

Enumerator
VACOPT_TERNARY_DEFAULT
VACOPT_TERNARY_DISABLED
VACOPT_TERNARY_ENABLED

Definition at line 195 of file vacuum.h.

{
    VACOPT_TERNARY_DEFAULT = 0,
    VACOPT_TERNARY_DISABLED,
    VACOPT_TERNARY_ENABLED,
} VacOptTernaryValue;

VacuumOption

enum VacuumOption

Enumerator
VACOPT_VACUUM
VACOPT_ANALYZE
VACOPT_VERBOSE
VACOPT_FREEZE
VACOPT_FULL
VACOPT_SKIP_LOCKED
VACOPT_SKIPTOAST
VACOPT_DISABLE_PAGE_SKIPPING

Definition at line 177 of file vacuum.h.

{
    VACOPT_VACUUM = 1 << 0,     /* do VACUUM */
    VACOPT_ANALYZE = 1 << 1,    /* do ANALYZE */
    VACOPT_VERBOSE = 1 << 2,    /* print progress info */
    VACOPT_FREEZE = 1 << 3,     /* FREEZE option */
    VACOPT_FULL = 1 << 4,       /* FULL (non-concurrent) vacuum */
    VACOPT_SKIP_LOCKED = 1 << 5,    /* skip if cannot get lock */
    VACOPT_SKIPTOAST = 1 << 6,  /* don't process the TOAST table, if any */
    VACOPT_DISABLE_PAGE_SKIPPING = 1 << 7   /* don't skip any pages */
} VacuumOption;

Function Documentation

analyze_rel()

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

Definition at line 119 of file analyze.c.

References acquire_sample_rows(), FdwRoutine::AnalyzeForeignTable, CHECK_FOR_INTERRUPTS, DEBUG2, do_analyze_rel(), elevel, ereport, errmsg(), GetFdwRoutineForRelation(), INFO, VacuumParams::log_min_duration, NoLock, VacuumParams::options, pgstat_progress_end_command(), pgstat_progress_start_command(), PROGRESS_COMMAND_ANALYZE, RelationData::rd_rel, relation_close(), RELATION_IS_OTHER_TEMP, RelationGetNumberOfBlocks, RelationGetRelationName, RelationGetRelid, ShareUpdateExclusiveLock, VACOPT_ANALYZE, VACOPT_VACUUM, VACOPT_VERBOSE, vacuum_is_relation_owner(), vacuum_open_relation(), and WARNING.

Referenced by vacuum().

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

    /* Select logging level */
    if (params->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.
     *
     * Make sure to generate only logs for ANALYZE in this case.
     */
    onerel = vacuum_open_relation(relid, relation, params->options & ~(VACOPT_VACUUM),
                                  params->log_min_duration >= 0,
                                  ShareUpdateExclusiveLock);

    /* leave if relation could not be opened or locked */
    if (!onerel)
        return;

    /*
     * Check if relation needs to be skipped based on ownership.  This check
     * happens also when building the relation list to analyze for a manual
     * operation, and needs to be done additionally here as ANALYZE could
     * happen across multiple transactions where relation ownership could have
     * changed in-between.  Make sure to generate only logs for ANALYZE in
     * this case.
     */
    if (!vacuum_is_relation_owner(RelationGetRelid(onerel),
                                  onerel->rd_rel,
                                  params->options & VACOPT_ANALYZE))
    {
        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 (!(params->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, initialize progress reporting.
     */
    pgstat_progress_start_command(PROGRESS_COMMAND_ANALYZE,
                                  RelationGetRelid(onerel));

    /*
     * 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, 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, 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);

    pgstat_progress_end_command();
}

anl_get_next_S()

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

Definition at line 288 of file sampling.c.

{
    double      result;

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

anl_init_selection_state()

double anl_init_selection_state

(

int

n

)

Definition at line 277 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);
}

anl_random_fract()

double anl_random_fract

(

void

)

Definition at line 266 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);
}

ExecVacuum()

void ExecVacuum	(	ParseState *	pstate,
		VacuumStmt *	vacstmt,
		bool	isTopLevel
	)

Definition at line 98 of file vacuum.c.

References analyze(), DefElem::arg, Assert, defGetBoolean(), defGetInt32(), DefElem::defname, ereport, errcode(), errmsg(), ERROR, VacuumParams::freeze_min_age, VacuumParams::freeze_table_age, get_vacopt_ternary_value(), VacuumParams::index_cleanup, VacuumStmt::is_vacuumcmd, VacuumParams::is_wraparound, lfirst, lfirst_node, DefElem::location, VacuumParams::log_min_duration, MAX_PARALLEL_WORKER_LIMIT, VacuumParams::multixact_freeze_min_age, VacuumParams::multixact_freeze_table_age, NIL, VacuumParams::nworkers, VacuumParams::options, VacuumStmt::options, parser_errposition(), VacuumStmt::rels, VacuumParams::truncate, VacuumRelation::va_cols, VACOPT_ANALYZE, VACOPT_DISABLE_PAGE_SKIPPING, VACOPT_FREEZE, VACOPT_FULL, VACOPT_SKIP_LOCKED, VACOPT_SKIPTOAST, VACOPT_TERNARY_DEFAULT, VACOPT_VACUUM, VACOPT_VERBOSE, vacuum(), and verbose.

Referenced by standard_ProcessUtility().

{
    VacuumParams params;
    bool        verbose = false;
    bool        skip_locked = false;
    bool        analyze = false;
    bool        freeze = false;
    bool        full = false;
    bool        disable_page_skipping = false;
    ListCell   *lc;

    /* Set default value */
    params.index_cleanup = VACOPT_TERNARY_DEFAULT;
    params.truncate = VACOPT_TERNARY_DEFAULT;

    /* By default parallel vacuum is enabled */
    params.nworkers = 0;

    /* Parse options list */
    foreach(lc, vacstmt->options)
    {
        DefElem    *opt = (DefElem *) lfirst(lc);

        /* Parse common options for VACUUM and ANALYZE */
        if (strcmp(opt->defname, "verbose") == 0)
            verbose = defGetBoolean(opt);
        else if (strcmp(opt->defname, "skip_locked") == 0)
            skip_locked = defGetBoolean(opt);
        else if (!vacstmt->is_vacuumcmd)
            ereport(ERROR,
                    (errcode(ERRCODE_SYNTAX_ERROR),
                     errmsg("unrecognized ANALYZE option \"%s\"", opt->defname),
                     parser_errposition(pstate, opt->location)));

        /* Parse options available on VACUUM */
        else if (strcmp(opt->defname, "analyze") == 0)
            analyze = defGetBoolean(opt);
        else if (strcmp(opt->defname, "freeze") == 0)
            freeze = defGetBoolean(opt);
        else if (strcmp(opt->defname, "full") == 0)
            full = defGetBoolean(opt);
        else if (strcmp(opt->defname, "disable_page_skipping") == 0)
            disable_page_skipping = defGetBoolean(opt);
        else if (strcmp(opt->defname, "index_cleanup") == 0)
            params.index_cleanup = get_vacopt_ternary_value(opt);
        else if (strcmp(opt->defname, "truncate") == 0)
            params.truncate = get_vacopt_ternary_value(opt);
        else if (strcmp(opt->defname, "parallel") == 0)
        {
            if (opt->arg == NULL)
            {
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("parallel option requires a value between 0 and %d",
                                MAX_PARALLEL_WORKER_LIMIT),
                         parser_errposition(pstate, opt->location)));
            }
            else
            {
                int         nworkers;

                nworkers = defGetInt32(opt);
                if (nworkers < 0 || nworkers > MAX_PARALLEL_WORKER_LIMIT)
                    ereport(ERROR,
                            (errcode(ERRCODE_SYNTAX_ERROR),
                             errmsg("parallel vacuum degree must be between 0 and %d",
                                    MAX_PARALLEL_WORKER_LIMIT),
                             parser_errposition(pstate, opt->location)));

                /*
                 * Disable parallel vacuum, if user has specified parallel
                 * degree as zero.
                 */
                if (nworkers == 0)
                    params.nworkers = -1;
                else
                    params.nworkers = nworkers;
            }
        }
        else
            ereport(ERROR,
                    (errcode(ERRCODE_SYNTAX_ERROR),
                     errmsg("unrecognized VACUUM option \"%s\"", opt->defname),
                     parser_errposition(pstate, opt->location)));
    }

    /* Set vacuum options */
    params.options =
        (vacstmt->is_vacuumcmd ? VACOPT_VACUUM : VACOPT_ANALYZE) |
        (verbose ? VACOPT_VERBOSE : 0) |
        (skip_locked ? VACOPT_SKIP_LOCKED : 0) |
        (analyze ? VACOPT_ANALYZE : 0) |
        (freeze ? VACOPT_FREEZE : 0) |
        (full ? VACOPT_FULL : 0) |
        (disable_page_skipping ? VACOPT_DISABLE_PAGE_SKIPPING : 0);

    /* sanity checks on options */
    Assert(params.options & (VACOPT_VACUUM | VACOPT_ANALYZE));
    Assert((params.options & VACOPT_VACUUM) ||
           !(params.options & (VACOPT_FULL | VACOPT_FREEZE)));
    Assert(!(params.options & VACOPT_SKIPTOAST));

    if ((params.options & VACOPT_FULL) && params.nworkers > 0)
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("VACUUM FULL cannot be performed in parallel")));

    /*
     * Make sure VACOPT_ANALYZE is specified if any column lists are present.
     */
    if (!(params.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 (params.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->rels, &params, NULL, isTopLevel);
}

std_typanalyze()

bool std_typanalyze

(

VacAttrStats *

stats

)

Definition at line 1680 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;
}

vac_close_indexes()

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

Definition at line 1994 of file vacuum.c.

References index_close(), and pfree().

Referenced by do_analyze_rel(), heap_vacuum_rel(), and parallel_vacuum_main().

{
    if (Irel == NULL)
        return;

    while (nindexes--)
    {
        Relation    ind = Irel[nindexes];

        index_close(ind, lockmode);
    }
    pfree(Irel);
}

vac_estimate_reltuples()

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

Definition at line 1138 of file vacuum.c.

References RelationData::rd_rel.

Referenced by 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      unscanned_pages;
    double      total_tuples;

    /* 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
     * estimate the number of tuples in the unscanned pages using that figure,
     * and finally add on the number of tuples in the scanned pages.
     */
    old_density = old_rel_tuples / old_rel_pages;
    unscanned_pages = (double) total_pages - (double) scanned_pages;
    total_tuples = old_density * unscanned_pages + scanned_tuples;
    return floor(total_tuples + 0.5);
}

vac_open_indexes()

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

Definition at line 1951 of file vacuum.c.

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

Referenced by do_analyze_rel(), heap_vacuum_rel(), and parallel_vacuum_main().

{
    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 (indrel->rd_index->indisready)
            (*Irel)[i++] = indrel;
        else
            index_close(indrel, lockmode);
    }

    *nindexes = i;

    list_free(indexoidlist);
}

vac_update_datfrozenxid()

void vac_update_datfrozenxid

(

void

)

Definition at line 1350 of file vacuum.c.

References AccessShareLock, Assert, DATABASEOID, elog, ERROR, ForceTransactionIdLimitUpdate(), GetOldestMultiXactId(), GetOldestNonRemovableTransactionId(), GETSTRUCT, heap_freetuple(), heap_inplace_update(), HeapTupleIsValid, InvalidOid, MultiXactIdIsValid, MultiXactIdPrecedes(), MyDatabaseId, ObjectIdGetDatum, ReadNewTransactionId(), ReadNextMultiXactId(), RowExclusiveLock, SearchSysCacheCopy1, systable_beginscan(), systable_endscan(), systable_getnext(), table_close(), table_open(), TransactionIdIsNormal, TransactionIdIsValid, 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
     * GetOldestNonRemovableTransactionId(), 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 = GetOldestNonRemovableTransactionId(NULL);

    /*
     * 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 = table_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)
        {
            Assert(!TransactionIdIsValid(classForm->relfrozenxid));
            Assert(!MultiXactIdIsValid(classForm->relminmxid));
            continue;
        }

        /*
         * Some table AMs might not need per-relation xid / multixid horizons.
         * It therefore seems reasonable to allow relfrozenxid and relminmxid
         * to not be set (i.e. set to their respective Invalid*Id)
         * independently. Thus validate and compute horizon for each only if
         * set.
         *
         * 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 & multixact SLRUs
         * before those relations have been scanned and cleaned up.
         */

        if (TransactionIdIsValid(classForm->relfrozenxid))
        {
            Assert(TransactionIdIsNormal(classForm->relfrozenxid));

            /* check for values in the future */
            if (TransactionIdPrecedes(lastSaneFrozenXid, classForm->relfrozenxid))
            {
                bogus = true;
                break;
            }

            /* determine new horizon */
            if (TransactionIdPrecedes(classForm->relfrozenxid, newFrozenXid))
                newFrozenXid = classForm->relfrozenxid;
        }

        if (MultiXactIdIsValid(classForm->relminmxid))
        {
            /* check for values in the future */
            if (MultiXactIdPrecedes(lastSaneMinMulti, classForm->relminmxid))
            {
                bogus = true;
                break;
            }

            /* determine new horizon */
            if (MultiXactIdPrecedes(classForm->relminmxid, newMinMulti))
                newMinMulti = classForm->relminmxid;
        }
    }

    /* we're done with pg_class */
    systable_endscan(scan);
    table_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 = table_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);
    table_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);
}

vac_update_relstats()

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 1223 of file vacuum.c.

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

Referenced by do_analyze_rel(), heap_vacuum_rel(), and update_index_statistics().

{
    Oid         relid = RelationGetRelid(relation);
    Relation    rd;
    HeapTuple   ctup;
    Form_pg_class pgcform;
    bool        dirty;

    rd = table_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;
        }

        /* 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);

    table_close(rd, RowExclusiveLock);
}

vacuum()

void vacuum	(	List *	relations,
		VacuumParams *	params,
		BufferAccessStrategy	bstrategy,
		bool	isTopLevel
	)

Definition at line 272 of file vacuum.c.

References ActiveSnapshotSet(), ALLOCSET_DEFAULT_SIZES, AllocSetContextCreate, analyze_rel(), Assert, BAS_VACUUM, CommandCounterIncrement(), CommitTransactionCommand(), cur, ereport, errcode(), errmsg(), ERROR, expand_vacuum_rel(), get_all_vacuum_rels(), GetAccessStrategy(), GetTransactionSnapshot(), IsAutoVacuumWorkerProcess(), IsInTransactionBlock(), lfirst_node, list_concat(), list_length(), MemoryContextDelete(), MemoryContextSwitchTo(), NIL, VacuumRelation::oid, VacuumParams::options, PG_END_TRY, PG_FINALLY, PG_TRY, pgstat_vacuum_stat(), PopActiveSnapshot(), PortalContext, PreventInTransactionBlock(), PushActiveSnapshot(), VacuumRelation::relation, StartTransactionCommand(), VacuumRelation::va_cols, vac_update_datfrozenxid(), VACOPT_ANALYZE, VACOPT_DISABLE_PAGE_SKIPPING, VACOPT_FULL, VACOPT_VACUUM, vacuum_rel(), VacuumCostActive, VacuumCostBalance, VacuumCostBalanceLocal, 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 = (params->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 (params->options & VACOPT_VACUUM)
    {
        PreventInTransactionBlock(isTopLevel, stmttype);
        in_outer_xact = false;
    }
    else
        in_outer_xact = IsInTransactionBlock(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 ((params->options & VACOPT_FULL) != 0 &&
        (params->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 ((params->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, params->options);
            old_context = MemoryContextSwitchTo(vac_context);
            newrels = list_concat(newrels, sublist);
            MemoryContextSwitchTo(old_context);
        }
        relations = newrels;
    }
    else
        relations = get_all_vacuum_rels(params->options);

    /*
     * 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 (params->options & VACOPT_VACUUM)
        use_own_xacts = true;
    else
    {
        Assert(params->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;
        VacuumCostBalanceLocal = 0;
        VacuumSharedCostBalance = NULL;
        VacuumActiveNWorkers = NULL;

        /*
         * Loop to process each selected relation.
         */
        foreach(cur, relations)
        {
            VacuumRelation *vrel = lfirst_node(VacuumRelation, cur);

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

            if (params->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, params,
                            vrel->va_cols, in_outer_xact, vac_strategy);

                if (use_own_xacts)
                {
                    PopActiveSnapshot();
                    CommitTransactionCommand();
                }
                else
                {
                    /*
                     * If we're not using separate xacts, better separate the
                     * ANALYZE actions with CCIs.  This avoids trouble if user
                     * says "ANALYZE t, t".
                     */
                    CommandCounterIncrement();
                }
            }
        }
    }
    PG_FINALLY();
    {
        in_vacuum = false;
        VacuumCostActive = false;
    }
    PG_END_TRY();

    /*
     * 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 ((params->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;
}

vacuum_delay_point()

void vacuum_delay_point

(

void

)

Definition at line 2015 of file vacuum.c.

References AutoVacuumUpdateDelay(), CHECK_FOR_INTERRUPTS, compute_parallel_delay(), InterruptPending, pg_usleep(), pgstat_report_wait_end(), pgstat_report_wait_start(), VacuumCostActive, VacuumCostBalance, VacuumCostDelay, VacuumCostLimit, and WAIT_EVENT_VACUUM_DELAY.

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(), gistvacuumpage(), hashbucketcleanup(), lazy_scan_heap(), lazy_vacuum_heap(), spgprocesspending(), and spgvacuumpage().

{
    double      msec = 0;

    /* Always check for interrupts */
    CHECK_FOR_INTERRUPTS();

    if (!VacuumCostActive || InterruptPending)
        return;

    /*
     * For parallel vacuum, the delay is computed based on the shared cost
     * balance.  See compute_parallel_delay.
     */
    if (VacuumSharedCostBalance != NULL)
        msec = compute_parallel_delay();
    else if (VacuumCostBalance >= VacuumCostLimit)
        msec = VacuumCostDelay * VacuumCostBalance / VacuumCostLimit;

    /* Nap if appropriate */
    if (msec > 0)
    {
        if (msec > VacuumCostDelay * 4)
            msec = VacuumCostDelay * 4;

        pgstat_report_wait_start(WAIT_EVENT_VACUUM_DELAY);
        pg_usleep((long) (msec * 1000));
        pgstat_report_wait_end();

        VacuumCostBalance = 0;

        /* update balance values for workers */
        AutoVacuumUpdateDelay();

        /* Might have gotten an interrupt while sleeping */
        CHECK_FOR_INTERRUPTS();
    }
}

vacuum_is_relation_owner()

bool vacuum_is_relation_owner	(	Oid	relid,
		Form_pg_class	reltuple,
		int	options
	)

Definition at line 533 of file vacuum.c.

References Assert, ereport, errmsg(), GetUserId(), MyDatabaseId, NameStr, pg_class_ownercheck(), pg_database_ownercheck(), relname, VACOPT_ANALYZE, VACOPT_VACUUM, and WARNING.

Referenced by analyze_rel(), expand_vacuum_rel(), get_all_vacuum_rels(), and vacuum_rel().

{
    char       *relname;

    Assert((options & (VACOPT_VACUUM | VACOPT_ANALYZE)) != 0);

    /*
     * Check permissions.
     *
     * We allow the user to vacuum or analyze 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 or analyze the rest of the DB --- is this appropriate?
     */
    if (pg_class_ownercheck(relid, GetUserId()) ||
        (pg_database_ownercheck(MyDatabaseId, GetUserId()) && !reltuple->relisshared))
        return true;

    relname = NameStr(reltuple->relname);

    if ((options & VACOPT_VACUUM) != 0)
    {
        if (reltuple->relisshared)
            ereport(WARNING,
                    (errmsg("skipping \"%s\" --- only superuser can vacuum it",
                            relname)));
        else if (reltuple->relnamespace == PG_CATALOG_NAMESPACE)
            ereport(WARNING,
                    (errmsg("skipping \"%s\" --- only superuser or database owner can vacuum it",
                            relname)));
        else
            ereport(WARNING,
                    (errmsg("skipping \"%s\" --- only table or database owner can vacuum it",
                            relname)));

        /*
         * For VACUUM ANALYZE, both logs could show up, but just generate
         * information for VACUUM as that would be the first one to be
         * processed.
         */
        return false;
    }

    if ((options & VACOPT_ANALYZE) != 0)
    {
        if (reltuple->relisshared)
            ereport(WARNING,
                    (errmsg("skipping \"%s\" --- only superuser can analyze it",
                            relname)));
        else if (reltuple->relnamespace == PG_CATALOG_NAMESPACE)
            ereport(WARNING,
                    (errmsg("skipping \"%s\" --- only superuser or database owner can analyze it",
                            relname)));
        else
            ereport(WARNING,
                    (errmsg("skipping \"%s\" --- only table or database owner can analyze it",
                            relname)));
    }

    return false;
}

vacuum_open_relation()

Relation vacuum_open_relation	(	Oid	relid,
		RangeVar *	relation,
		int	options,
		bool	verbose,
		LOCKMODE	lmode
	)

Definition at line 607 of file vacuum.c.

References Assert, ConditionalLockRelationOid(), elevel, ereport, errcode(), ERRCODE_UNDEFINED_TABLE, errmsg(), IsAutoVacuumWorkerProcess(), LOG, NoLock, RangeVar::relname, try_relation_open(), VACOPT_ANALYZE, VACOPT_SKIP_LOCKED, VACOPT_VACUUM, and WARNING.

Referenced by analyze_rel(), and vacuum_rel().

{
    Relation    onerel;
    bool        rel_lock = true;
    int         elevel;

    Assert((options & (VACOPT_VACUUM | VACOPT_ANALYZE)) != 0);

    /*
     * Open the relation and get the appropriate lock on it.
     *
     * There's a race condition here: the relation may have gone away since
     * the last time we saw it.  If so, we don't need to vacuum or analyze 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_SKIP_LOCKED))
        onerel = try_relation_open(relid, lmode);
    else if (ConditionalLockRelationOid(relid, lmode))
        onerel = try_relation_open(relid, NoLock);
    else
    {
        onerel = NULL;
        rel_lock = false;
    }

    /* if relation is opened, leave */
    if (onerel)
        return onerel;

    /*
     * Relation could not be opened, hence generate if possible a log
     * informing on the situation.
     *
     * If the RangeVar is not defined, we do not have enough information to
     * provide a meaningful log statement.  Chances are that the caller has
     * intentionally not provided this information so that this logging is
     * skipped, anyway.
     */
    if (relation == NULL)
        return NULL;

    /*
     * Determine the log level.
     *
     * For manual VACUUM or ANALYZE, we emit a WARNING to match the log
     * statements in the permission checks; otherwise, only log if the caller
     * so requested.
     */
    if (!IsAutoVacuumWorkerProcess())
        elevel = WARNING;
    else if (verbose)
        elevel = LOG;
    else
        return NULL;

    if ((options & VACOPT_VACUUM) != 0)
    {
        if (!rel_lock)
            ereport(elevel,
                    (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
                     errmsg("skipping vacuum of \"%s\" --- lock not available",
                            relation->relname)));
        else
            ereport(elevel,
                    (errcode(ERRCODE_UNDEFINED_TABLE),
                     errmsg("skipping vacuum of \"%s\" --- relation no longer exists",
                            relation->relname)));

        /*
         * For VACUUM ANALYZE, both logs could show up, but just generate
         * information for VACUUM as that would be the first one to be
         * processed.
         */
        return NULL;
    }

    if ((options & VACOPT_ANALYZE) != 0)
    {
        if (!rel_lock)
            ereport(elevel,
                    (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
                     errmsg("skipping analyze of \"%s\" --- lock not available",
                            relation->relname)));
        else
            ereport(elevel,
                    (errcode(ERRCODE_UNDEFINED_TABLE),
                     errmsg("skipping analyze of \"%s\" --- relation no longer exists",
                            relation->relname)));
    }

    return NULL;
}

vacuum_set_xid_limits()

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 929 of file vacuum.c.

References Assert, autovacuum_freeze_max_age, ereport, errhint(), errmsg(), FirstMultiXactId, FirstNormalTransactionId, GetOldestMultiXactId(), GetOldestNonRemovableTransactionId(), Min, MultiXactIdPrecedes(), MultiXactMemberFreezeThreshold(), OldSnapshotThresholdActive(), ReadNewTransactionId(), ReadNextMultiXactId(), SetOldSnapshotThresholdTimestamp(), 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_table_data(), and heap_vacuum_rel().

{
    int         freezemin;
    int         mxid_freezemin;
    int         effective_multixact_freeze_max_age;
    TransactionId limit;
    TransactionId safeLimit;
    MultiXactId oldestMxact;
    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 = GetOldestNonRemovableTransactionId(rel);

    if (OldSnapshotThresholdActive())
    {
        TransactionId limit_xmin;
        TimestampTz limit_ts;

        if (TransactionIdLimitedForOldSnapshots(*oldestXmin, rel, &limit_xmin, &limit_ts))
        {
            /*
             * TODO: We should only set the threshold if we are pruning on the
             * basis of the increased limits. Not as crucial here as it is for
             * opportunistic pruning (which often happens at a much higher
             * frequency), but would still be a significant improvement.
             */
            SetOldSnapshotThresholdTimestamp(limit_ts, limit_xmin);
            *oldestXmin = limit_xmin;
        }
    }

    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.\n"
                         "You might also need to commit or roll back old prepared transactions, or drop stale replication slots.")));
        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 */
    oldestMxact = GetOldestMultiXactId();
    mxactLimit = oldestMxact - 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.")));
        /* Use the safe limit, unless an older mxact is still running */
        if (MultiXactIdPrecedes(oldestMxact, safeMxactLimit))
            mxactLimit = oldestMxact;
        else
            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

default_statistics_target

PGDLLIMPORT int default_statistics_target

Definition at line 81 of file analyze.c.

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

vacuum_freeze_min_age

int vacuum_freeze_min_age

Definition at line 61 of file vacuum.c.

Referenced by do_autovacuum(), and vacuum_set_xid_limits().

vacuum_freeze_table_age

int vacuum_freeze_table_age

Definition at line 62 of file vacuum.c.

Referenced by do_autovacuum(), and vacuum_set_xid_limits().

vacuum_multixact_freeze_min_age

int vacuum_multixact_freeze_min_age

Definition at line 63 of file vacuum.c.

Referenced by do_autovacuum(), and vacuum_set_xid_limits().

vacuum_multixact_freeze_table_age

int vacuum_multixact_freeze_table_age

Definition at line 64 of file vacuum.c.

Referenced by do_autovacuum(), and vacuum_set_xid_limits().

VacuumActiveNWorkers

pg_atomic_uint32* VacuumActiveNWorkers

Definition at line 77 of file vacuum.c.

Referenced by lazy_parallel_vacuum_indexes(), parallel_vacuum_index(), parallel_vacuum_main(), and vacuum_indexes_leader().

VacuumCostBalanceLocal

int VacuumCostBalanceLocal

Definition at line 78 of file vacuum.c.

Referenced by compute_parallel_delay(), lazy_parallel_vacuum_indexes(), parallel_vacuum_main(), and vacuum().

VacuumSharedCostBalance

pg_atomic_uint32* VacuumSharedCostBalance

Definition at line 76 of file vacuum.c.

Referenced by lazy_parallel_vacuum_indexes(), and parallel_vacuum_main().