vacuum.c File Reference

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

Include dependency graph for vacuum.c:

Go to the source code of this file.

Functions
static List *	expand_vacuum_rel (VacuumRelation *vrel, int options)
static List *	get_all_vacuum_rels (int options)
static void	vac_truncate_clog (TransactionId frozenXID, MultiXactId minMulti, TransactionId lastSaneFrozenXid, MultiXactId lastSaneMinMulti)
static bool	vacuum_rel (Oid relid, RangeVar *relation, VacuumParams *params)
static double	compute_parallel_delay (void)
static VacOptValue	get_vacoptval_from_boolean (DefElem *def)
static bool	vac_tid_reaped (ItemPointer itemptr, void *state)
static int	vac_cmp_itemptr (const void *left, const void *right)
void	ExecVacuum (ParseState *pstate, VacuumStmt *vacstmt, bool isTopLevel)
void	vacuum (List *relations, VacuumParams *params, BufferAccessStrategy bstrategy, bool isTopLevel)
bool	vacuum_is_permitted_for_relation (Oid relid, Form_pg_class reltuple, bits32 options)
Relation	vacuum_open_relation (Oid relid, RangeVar *relation, bits32 options, bool verbose, LOCKMODE lmode)
bool	vacuum_set_xid_limits (Relation rel, const VacuumParams *params, TransactionId *OldestXmin, MultiXactId *OldestMxact, TransactionId *FreezeLimit, MultiXactId *MultiXactCutoff)
bool	vacuum_xid_failsafe_check (TransactionId relfrozenxid, MultiXactId relminmxid)
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 *frozenxid_updated, bool *minmulti_updated, bool in_outer_xact)
void	vac_update_datfrozenxid (void)
void	vac_open_indexes (Relation relation, LOCKMODE lockmode, int *nindexes, Relation **Irel)
void	vac_close_indexes (int nindexes, Relation *Irel, LOCKMODE lockmode)
void	vacuum_delay_point (void)
IndexBulkDeleteResult *	vac_bulkdel_one_index (IndexVacuumInfo *ivinfo, IndexBulkDeleteResult *istat, VacDeadItems *dead_items)
IndexBulkDeleteResult *	vac_cleanup_one_index (IndexVacuumInfo *ivinfo, IndexBulkDeleteResult *istat)
Size	vac_max_items_to_alloc_size (int max_items)

Variables
int	vacuum_freeze_min_age
int	vacuum_freeze_table_age
int	vacuum_multixact_freeze_min_age
int	vacuum_multixact_freeze_table_age
int	vacuum_failsafe_age
int	vacuum_multixact_failsafe_age
static MemoryContext	vac_context = NULL
static BufferAccessStrategy	vac_strategy
pg_atomic_uint32 *	VacuumSharedCostBalance = NULL
pg_atomic_uint32 *	VacuumActiveNWorkers = NULL
int	VacuumCostBalanceLocal = 0

Function Documentation

compute_parallel_delay()

static double compute_parallel_delay ( void  )

static

Definition at line 2230 of file vacuum.c.

{
    double      msec = 0;
    uint32      shared_balance;
    int         nworkers;
 
    /* Parallel vacuum must be active */
    Assert(VacuumSharedCostBalance);
 
    nworkers = pg_atomic_read_u32(VacuumActiveNWorkers);
 
    /* At least count itself */
    Assert(nworkers >= 1);
 
    /* Update the shared cost balance value atomically */
    shared_balance = pg_atomic_add_fetch_u32(VacuumSharedCostBalance, VacuumCostBalance);
 
    /* Compute the total local balance for the current worker */
    VacuumCostBalanceLocal += VacuumCostBalance;
 
    if ((shared_balance >= VacuumCostLimit) &&
        (VacuumCostBalanceLocal > 0.5 * ((double) VacuumCostLimit / nworkers)))
    {
        /* Compute sleep time based on the local cost balance */
        msec = VacuumCostDelay * VacuumCostBalanceLocal / VacuumCostLimit;
        pg_atomic_sub_fetch_u32(VacuumSharedCostBalance, VacuumCostBalanceLocal);
        VacuumCostBalanceLocal = 0;
    }
 
    /*
     * Reset the local balance as we accumulated it into the shared value.
     */
    VacuumCostBalance = 0;
 
    return msec;
}

References Assert(), pg_atomic_add_fetch_u32(), pg_atomic_read_u32(), pg_atomic_sub_fetch_u32(), VacuumActiveNWorkers, VacuumCostBalance, VacuumCostBalanceLocal, VacuumCostDelay, VacuumCostLimit, and VacuumSharedCostBalance.

Referenced by vacuum_delay_point().

ExecVacuum()

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

Definition at line 107 of file vacuum.c.

{
    VacuumParams params;
    bool        verbose = false;
    bool        skip_locked = false;
    bool        analyze = false;
    bool        freeze = false;
    bool        full = false;
    bool        disable_page_skipping = false;
    bool        process_toast = true;
    ListCell   *lc;
 
    /* index_cleanup and truncate values unspecified for now */
    params.index_cleanup = VACOPTVALUE_UNSPECIFIED;
    params.truncate = VACOPTVALUE_UNSPECIFIED;
 
    /* 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)
        {
            /* Interpret no string as the default, which is 'auto' */
            if (!opt->arg)
                params.index_cleanup = VACOPTVALUE_AUTO;
            else
            {
                char       *sval = defGetString(opt);
 
                /* Try matching on 'auto' string, or fall back on boolean */
                if (pg_strcasecmp(sval, "auto") == 0)
                    params.index_cleanup = VACOPTVALUE_AUTO;
                else
                    params.index_cleanup = get_vacoptval_from_boolean(opt);
            }
        }
        else if (strcmp(opt->defname, "process_toast") == 0)
            process_toast = defGetBoolean(opt);
        else if (strcmp(opt->defname, "truncate") == 0)
            params.truncate = get_vacoptval_from_boolean(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 workers for vacuum 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) |
        (process_toast ? VACOPT_PROCESS_TOAST : 0);
 
    /* sanity checks on options */
    Assert(params.options & (VACOPT_VACUUM | VACOPT_ANALYZE));
    Assert((params.options & VACOPT_VACUUM) ||
           !(params.options & (VACOPT_FULL | VACOPT_FREEZE)));
 
    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))
    {
        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 uses VACOPT_VERBOSE instead of log_min_duration */
    params.log_min_duration = -1;
 
    /* Now go through the common routine */
    vacuum(vacstmt->rels, &params, NULL, isTopLevel);
}

References analyze(), DefElem::arg, Assert(), defGetBoolean(), defGetInt32(), defGetString(), DefElem::defname, ereport, errcode(), errmsg(), ERROR, VacuumParams::freeze_min_age, VacuumParams::freeze_table_age, get_vacoptval_from_boolean(), 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(), pg_strcasecmp(), VacuumStmt::rels, VacuumParams::truncate, VacuumRelation::va_cols, VACOPT_ANALYZE, VACOPT_DISABLE_PAGE_SKIPPING, VACOPT_FREEZE, VACOPT_FULL, VACOPT_PROCESS_TOAST, VACOPT_SKIP_LOCKED, VACOPT_VACUUM, VACOPT_VERBOSE, VACOPTVALUE_AUTO, VACOPTVALUE_UNSPECIFIED, vacuum(), and verbose.

Referenced by standard_ProcessUtility().

expand_vacuum_rel()

static List * expand_vacuum_rel ( VacuumRelation *  vrel, int  options  )

static

Definition at line 726 of file vacuum.c.

{
    List       *vacrels = NIL;
    MemoryContext oldcontext;
 
    /* If caller supplied OID, there's nothing we need do here. */
    if (OidIsValid(vrel->oid))
    {
        oldcontext = MemoryContextSwitchTo(vac_context);
        vacrels = lappend(vacrels, vrel);
        MemoryContextSwitchTo(oldcontext);
    }
    else
    {
        /* Process a specific relation, and possibly partitions thereof */
        Oid         relid;
        HeapTuple   tuple;
        Form_pg_class classForm;
        bool        include_parts;
        int         rvr_opts;
 
        /*
         * Since autovacuum workers supply OIDs when calling vacuum(), no
         * autovacuum worker should reach this code.
         */
        Assert(!IsAutoVacuumWorkerProcess());
 
        /*
         * We transiently take AccessShareLock to protect the syscache lookup
         * below, as well as find_all_inheritors's expectation that the caller
         * holds some lock on the starting relation.
         */
        rvr_opts = (options & VACOPT_SKIP_LOCKED) ? RVR_SKIP_LOCKED : 0;
        relid = RangeVarGetRelidExtended(vrel->relation,
                                         AccessShareLock,
                                         rvr_opts,
                                         NULL, NULL);
 
        /*
         * If the lock is unavailable, emit the same log statement that
         * vacuum_rel() and analyze_rel() would.
         */
        if (!OidIsValid(relid))
        {
            if (options & VACOPT_VACUUM)
                ereport(WARNING,
                        (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
                         errmsg("skipping vacuum of \"%s\" --- lock not available",
                                vrel->relation->relname)));
            else
                ereport(WARNING,
                        (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
                         errmsg("skipping analyze of \"%s\" --- lock not available",
                                vrel->relation->relname)));
            return vacrels;
        }
 
        /*
         * To check whether the relation is a partitioned table and its
         * ownership, fetch its syscache entry.
         */
        tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
        if (!HeapTupleIsValid(tuple))
            elog(ERROR, "cache lookup failed for relation %u", relid);
        classForm = (Form_pg_class) GETSTRUCT(tuple);
 
        /*
         * Make a returnable VacuumRelation for this rel if the user has the
         * required privileges.
         */
        if (vacuum_is_permitted_for_relation(relid, classForm, options))
        {
            oldcontext = MemoryContextSwitchTo(vac_context);
            vacrels = lappend(vacrels, makeVacuumRelation(vrel->relation,
                                                          relid,
                                                          vrel->va_cols));
            MemoryContextSwitchTo(oldcontext);
        }
 
 
        include_parts = (classForm->relkind == RELKIND_PARTITIONED_TABLE);
        ReleaseSysCache(tuple);
 
        /*
         * If it is, make relation list entries for its partitions.  Note that
         * the list returned by find_all_inheritors() includes the passed-in
         * OID, so we have to skip that.  There's no point in taking locks on
         * the individual partitions yet, and doing so would just add
         * unnecessary deadlock risk.  For this last reason we do not check
         * yet the ownership of the partitions, which get added to the list to
         * process.  Ownership will be checked later on anyway.
         */
        if (include_parts)
        {
            List       *part_oids = find_all_inheritors(relid, NoLock, NULL);
            ListCell   *part_lc;
 
            foreach(part_lc, part_oids)
            {
                Oid         part_oid = lfirst_oid(part_lc);
 
                if (part_oid == relid)
                    continue;   /* ignore original table */
 
                /*
                 * We omit a RangeVar since it wouldn't be appropriate to
                 * complain about failure to open one of these relations
                 * later.
                 */
                oldcontext = MemoryContextSwitchTo(vac_context);
                vacrels = lappend(vacrels, makeVacuumRelation(NULL,
                                                              part_oid,
                                                              vrel->va_cols));
                MemoryContextSwitchTo(oldcontext);
            }
        }
 
        /*
         * Release lock again.  This means that by the time we actually try to
         * process the table, it might be gone or renamed.  In the former case
         * we'll silently ignore it; in the latter case we'll process it
         * anyway, but we must beware that the RangeVar doesn't necessarily
         * identify it anymore.  This isn't ideal, perhaps, but there's little
         * practical alternative, since we're typically going to commit this
         * transaction and begin a new one between now and then.  Moreover,
         * holding locks on multiple relations would create significant risk
         * of deadlock.
         */
        UnlockRelationOid(relid, AccessShareLock);
    }
 
    return vacrels;
}

References AccessShareLock, Assert(), elog(), ereport, errcode(), errmsg(), ERROR, find_all_inheritors(), GETSTRUCT, HeapTupleIsValid, IsAutoVacuumWorkerProcess(), lappend(), lfirst_oid, makeVacuumRelation(), MemoryContextSwitchTo(), NIL, NoLock, ObjectIdGetDatum(), VacuumRelation::oid, OidIsValid, RangeVarGetRelidExtended(), VacuumRelation::relation, ReleaseSysCache(), RangeVar::relname, RELOID, RVR_SKIP_LOCKED, SearchSysCache1(), UnlockRelationOid(), VacuumRelation::va_cols, vac_context, VACOPT_SKIP_LOCKED, VACOPT_VACUUM, vacuum_is_permitted_for_relation(), and WARNING.

Referenced by vacuum().

get_all_vacuum_rels()

static List * get_all_vacuum_rels ( int  options )

static

Definition at line 865 of file vacuum.c.

{
    List       *vacrels = NIL;
    Relation    pgclass;
    TableScanDesc scan;
    HeapTuple   tuple;
 
    pgclass = table_open(RelationRelationId, AccessShareLock);
 
    scan = table_beginscan_catalog(pgclass, 0, NULL);
 
    while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
    {
        Form_pg_class classForm = (Form_pg_class) GETSTRUCT(tuple);
        MemoryContext oldcontext;
        Oid         relid = classForm->oid;
 
        /* check permissions of relation */
        if (!vacuum_is_permitted_for_relation(relid, classForm, options))
            continue;
 
        /*
         * We include partitioned tables here; depending on which operation is
         * to be performed, caller will decide whether to process or ignore
         * them.
         */
        if (classForm->relkind != RELKIND_RELATION &&
            classForm->relkind != RELKIND_MATVIEW &&
            classForm->relkind != RELKIND_PARTITIONED_TABLE)
            continue;
 
        /*
         * Build VacuumRelation(s) specifying the table OIDs to be processed.
         * We omit a RangeVar since it wouldn't be appropriate to complain
         * about failure to open one of these relations later.
         */
        oldcontext = MemoryContextSwitchTo(vac_context);
        vacrels = lappend(vacrels, makeVacuumRelation(NULL,
                                                      relid,
                                                      NIL));
        MemoryContextSwitchTo(oldcontext);
    }
 
    table_endscan(scan);
    table_close(pgclass, AccessShareLock);
 
    return vacrels;
}

References AccessShareLock, ForwardScanDirection, GETSTRUCT, heap_getnext(), lappend(), makeVacuumRelation(), MemoryContextSwitchTo(), NIL, table_beginscan_catalog(), table_close(), table_endscan(), table_open(), vac_context, and vacuum_is_permitted_for_relation().

Referenced by vacuum().

get_vacoptval_from_boolean()

static VacOptValue get_vacoptval_from_boolean ( DefElem *  def )

static

Definition at line 2274 of file vacuum.c.

{
    return defGetBoolean(def) ? VACOPTVALUE_ENABLED : VACOPTVALUE_DISABLED;
}

References defGetBoolean(), VACOPTVALUE_DISABLED, and VACOPTVALUE_ENABLED.

Referenced by ExecVacuum().

vac_bulkdel_one_index()

IndexBulkDeleteResult* vac_bulkdel_one_index	(	IndexVacuumInfo *	ivinfo,
		IndexBulkDeleteResult *	istat,
		VacDeadItems *	dead_items
	)

Definition at line 2285 of file vacuum.c.

{
    /* Do bulk deletion */
    istat = index_bulk_delete(ivinfo, istat, vac_tid_reaped,
                              (void *) dead_items);
 
    ereport(ivinfo->message_level,
            (errmsg("scanned index \"%s\" to remove %d row versions",
                    RelationGetRelationName(ivinfo->index),
                    dead_items->num_items)));
 
    return istat;
}

References ereport, errmsg(), IndexVacuumInfo::index, index_bulk_delete(), IndexVacuumInfo::message_level, VacDeadItems::num_items, RelationGetRelationName, and vac_tid_reaped().

Referenced by lazy_vacuum_one_index(), and parallel_vacuum_process_one_index().

vac_cleanup_one_index()

IndexBulkDeleteResult* vac_cleanup_one_index	(	IndexVacuumInfo *	ivinfo,
		IndexBulkDeleteResult *	istat
	)

Definition at line 2306 of file vacuum.c.

{
    istat = index_vacuum_cleanup(ivinfo, istat);
 
    if (istat)
        ereport(ivinfo->message_level,
                (errmsg("index \"%s\" now contains %.0f row versions in %u pages",
                        RelationGetRelationName(ivinfo->index),
                        istat->num_index_tuples,
                        istat->num_pages),
                 errdetail("%.0f index row versions were removed.\n"
                           "%u index pages were newly deleted.\n"
                           "%u index pages are currently deleted, of which %u are currently reusable.",
                           istat->tuples_removed,
                           istat->pages_newly_deleted,
                           istat->pages_deleted, istat->pages_free)));
 
    return istat;
}

References ereport, errdetail(), errmsg(), IndexVacuumInfo::index, index_vacuum_cleanup(), IndexVacuumInfo::message_level, IndexBulkDeleteResult::num_index_tuples, IndexBulkDeleteResult::num_pages, IndexBulkDeleteResult::pages_deleted, IndexBulkDeleteResult::pages_free, IndexBulkDeleteResult::pages_newly_deleted, RelationGetRelationName, and IndexBulkDeleteResult::tuples_removed.

Referenced by lazy_cleanup_one_index(), and parallel_vacuum_process_one_index().

vac_close_indexes()

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

Definition at line 2145 of file vacuum.c.

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

References index_close(), and pfree().

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

vac_cmp_itemptr()

static int vac_cmp_itemptr ( const void *  left, const void *  right  )

static

Definition at line 2380 of file vacuum.c.

{
    BlockNumber lblk,
                rblk;
    OffsetNumber loff,
                roff;
 
    lblk = ItemPointerGetBlockNumber((ItemPointer) left);
    rblk = ItemPointerGetBlockNumber((ItemPointer) right);
 
    if (lblk < rblk)
        return -1;
    if (lblk > rblk)
        return 1;
 
    loff = ItemPointerGetOffsetNumber((ItemPointer) left);
    roff = ItemPointerGetOffsetNumber((ItemPointer) right);
 
    if (loff < roff)
        return -1;
    if (loff > roff)
        return 1;
 
    return 0;
}

References ItemPointerGetBlockNumber(), and ItemPointerGetOffsetNumber().

Referenced by vac_tid_reaped().

vac_estimate_reltuples()

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

Definition at line 1186 of file vacuum.c.

{
    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;
 
    /*
     * When successive VACUUM commands scan the same few pages again and
     * again, without anything from the table really changing, there is a risk
     * that our beliefs about tuple density will gradually become distorted.
     * This might be caused by vacuumlazy.c implementation details, such as
     * its tendency to always scan the last heap page.  Handle that here.
     *
     * If the relation is _exactly_ the same size according to the existing
     * pg_class entry, and only a few of its pages (less than 2%) were
     * scanned, keep the existing value of reltuples.  Also keep the existing
     * value when only a subset of rel's pages <= a single page were scanned.
     *
     * (Note: we might be returning -1 here.)
     */
    if (old_rel_pages == total_pages &&
        scanned_pages < (double) total_pages * 0.02)
        return old_rel_tuples;
    if (scanned_pages <= 1)
        return old_rel_tuples;
 
    /*
     * If old density is unknown, we can't do much except scale up
     * scanned_tuples to match total_pages.
     */
    if (old_rel_tuples < 0 || 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);
}

References RelationData::rd_rel.

Referenced by lazy_scan_heap(), and statapprox_heap().

vac_max_items_to_alloc_size()

Size vac_max_items_to_alloc_size

(

int

max_items

)

Definition at line 2331 of file vacuum.c.

{
    Assert(max_items <= MAXDEADITEMS(MaxAllocSize));
 
    return offsetof(VacDeadItems, items) + sizeof(ItemPointerData) * max_items;
}

References Assert(), MaxAllocSize, and MAXDEADITEMS.

Referenced by dead_items_alloc(), and parallel_vacuum_init().

vac_open_indexes()

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

Definition at line 2102 of file vacuum.c.

{
    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);
}

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().

vac_tid_reaped()

static bool vac_tid_reaped ( ItemPointer  itemptr, void *  state  )

static

Definition at line 2346 of file vacuum.c.

{
    VacDeadItems *dead_items = (VacDeadItems *) state;
    int64       litem,
                ritem,
                item;
    ItemPointer res;
 
    litem = itemptr_encode(&dead_items->items[0]);
    ritem = itemptr_encode(&dead_items->items[dead_items->num_items - 1]);
    item = itemptr_encode(itemptr);
 
    /*
     * Doing a simple bound check before bsearch() is useful to avoid the
     * extra cost of bsearch(), especially if dead items on the heap are
     * concentrated in a certain range.  Since this function is called for
     * every index tuple, it pays to be really fast.
     */
    if (item < litem || item > ritem)
        return false;
 
    res = (ItemPointer) bsearch((void *) itemptr,
                                (void *) dead_items->items,
                                dead_items->num_items,
                                sizeof(ItemPointerData),
                                vac_cmp_itemptr);
 
    return (res != NULL);
}

References itemptr_encode(), VacDeadItems::items, VacDeadItems::num_items, res, and vac_cmp_itemptr().

Referenced by vac_bulkdel_one_index().

vac_truncate_clog()

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

static

Definition at line 1663 of file vacuum.c.

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

References AccessShareLock, AdvanceOldestCommitTsXid(), Assert(), datfrozenxid, datminmxid, ereport, errdetail(), errmsg(), FormData_pg_database, ForwardScanDirection, GETSTRUCT, heap_getnext(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MultiXactIdIsValid, MultiXactIdPrecedes(), MyDatabaseId, ReadNextTransactionId(), SetMultiXactIdLimit(), SetTransactionIdLimit(), table_beginscan_catalog(), table_close(), table_endscan(), table_open(), TransactionIdIsNormal, TransactionIdPrecedes(), TruncateCLOG(), TruncateCommitTs(), TruncateMultiXact(), and WARNING.

Referenced by vac_update_datfrozenxid().

vac_update_datfrozenxid()

void vac_update_datfrozenxid

(

void

)

Definition at line 1449 of file vacuum.c.

{
    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;
    ScanKeyData key[1];
 
    /*
     * Restrict this task to one backend per database.  This avoids race
     * conditions that would move datfrozenxid or datminmxid backward.  It
     * avoids calling vac_truncate_clog() with a datfrozenxid preceding a
     * datfrozenxid passed to an earlier vac_truncate_clog() call.
     */
    LockDatabaseFrozenIds(ExclusiveLock);
 
    /*
     * 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 = ReadNextTransactionId();
    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);
 
    /*
     * Get the pg_database tuple to scribble on.  Note that this does not
     * directly rely on the syscache to avoid issues with flattened toast
     * values for the in-place update.
     */
    ScanKeyInit(&key[0],
                Anum_pg_database_oid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(MyDatabaseId));
 
    scan = systable_beginscan(relation, DatabaseOidIndexId, true,
                              NULL, 1, key);
    tuple = systable_getnext(scan);
    tuple = heap_copytuple(tuple);
    systable_endscan(scan);
 
    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);
}

References AccessShareLock, Assert(), BTEqualStrategyNumber, elog(), ERROR, ExclusiveLock, ForceTransactionIdLimitUpdate(), GetOldestMultiXactId(), GetOldestNonRemovableTransactionId(), GETSTRUCT, heap_copytuple(), heap_freetuple(), heap_inplace_update(), HeapTupleIsValid, InvalidOid, sort-test::key, LockDatabaseFrozenIds(), MultiXactIdIsValid, MultiXactIdPrecedes(), MyDatabaseId, ObjectIdGetDatum(), ReadNextMultiXactId(), ReadNextTransactionId(), RowExclusiveLock, ScanKeyInit(), systable_beginscan(), systable_endscan(), systable_getnext(), table_close(), table_open(), TransactionIdIsNormal, TransactionIdIsValid, TransactionIdPrecedes(), and vac_truncate_clog().

Referenced by do_autovacuum(), and vacuum().

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 *	frozenxid_updated,
		bool *	minmulti_updated,
		bool	in_outer_xact
	)

Definition at line 1282 of file vacuum.c.

{
    Oid         relid = RelationGetRelid(relation);
    Relation    rd;
    HeapTuple   ctup;
    Form_pg_class pgcform;
    bool        dirty,
                futurexid,
                futuremxid;
    TransactionId oldfrozenxid;
    MultiXactId oldminmulti;
 
    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.  However, if the
     * stored relfrozenxid is "in the future" then it seems best to assume
     * it's corrupt, and overwrite with the oldest remaining XID in the table.
     * This should match vac_update_datfrozenxid() concerning what we consider
     * to be "in the future".
     */
    oldfrozenxid = pgcform->relfrozenxid;
    futurexid = false;
    if (frozenxid_updated)
        *frozenxid_updated = false;
    if (TransactionIdIsNormal(frozenxid) && oldfrozenxid != frozenxid)
    {
        bool        update = false;
 
        if (TransactionIdPrecedes(oldfrozenxid, frozenxid))
            update = true;
        else if (TransactionIdPrecedes(ReadNextTransactionId(), oldfrozenxid))
            futurexid = update = true;
 
        if (update)
        {
            pgcform->relfrozenxid = frozenxid;
            dirty = true;
            if (frozenxid_updated)
                *frozenxid_updated = true;
        }
    }
 
    /* Similarly for relminmxid */
    oldminmulti = pgcform->relminmxid;
    futuremxid = false;
    if (minmulti_updated)
        *minmulti_updated = false;
    if (MultiXactIdIsValid(minmulti) && oldminmulti != minmulti)
    {
        bool        update = false;
 
        if (MultiXactIdPrecedes(oldminmulti, minmulti))
            update = true;
        else if (MultiXactIdPrecedes(ReadNextMultiXactId(), oldminmulti))
            futuremxid = update = true;
 
        if (update)
        {
            pgcform->relminmxid = minmulti;
            dirty = true;
            if (minmulti_updated)
                *minmulti_updated = true;
        }
    }
 
    /* If anything changed, write out the tuple. */
    if (dirty)
        heap_inplace_update(rd, ctup);
 
    table_close(rd, RowExclusiveLock);
 
    if (futurexid)
        ereport(WARNING,
                (errcode(ERRCODE_DATA_CORRUPTED),
                 errmsg_internal("overwrote invalid relfrozenxid value %u with new value %u for table \"%s\"",
                                 oldfrozenxid, frozenxid,
                                 RelationGetRelationName(relation))));
    if (futuremxid)
        ereport(WARNING,
                (errcode(ERRCODE_DATA_CORRUPTED),
                 errmsg_internal("overwrote invalid relminmxid value %u with new value %u for table \"%s\"",
                                 oldminmulti, minmulti,
                                 RelationGetRelationName(relation))));
}

References elog(), ereport, errcode(), ERRCODE_DATA_CORRUPTED, errmsg_internal(), ERROR, GETSTRUCT, heap_inplace_update(), HeapTupleIsValid, MultiXactIdIsValid, MultiXactIdPrecedes(), ObjectIdGetDatum(), RelationData::rd_rules, ReadNextMultiXactId(), ReadNextTransactionId(), RelationGetRelationName, RelationGetRelid, RELOID, RowExclusiveLock, SearchSysCacheCopy1, table_close(), table_open(), TransactionIdIsNormal, TransactionIdPrecedes(), RelationData::trigdesc, and WARNING.

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

vacuum()

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

Definition at line 296 of file vacuum.c.

{
    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")));
 
    /* sanity check for PROCESS_TOAST */
    if ((params->options & VACOPT_FULL) != 0 &&
        (params->options & VACOPT_PROCESS_TOAST) == 0)
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("PROCESS_TOAST required with VACUUM FULL")));
 
    /*
     * 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;
}

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, PopActiveSnapshot(), PortalContext, PreventInTransactionBlock(), PushActiveSnapshot(), VacuumRelation::relation, StartTransactionCommand(), VacuumRelation::va_cols, vac_context, vac_strategy, vac_update_datfrozenxid(), VACOPT_ANALYZE, VACOPT_DISABLE_PAGE_SKIPPING, VACOPT_FULL, VACOPT_PROCESS_TOAST, VACOPT_VACUUM, vacuum_rel(), VacuumActiveNWorkers, VacuumCostActive, VacuumCostBalance, VacuumCostBalanceLocal, VacuumCostDelay, VacuumPageDirty, VacuumPageHit, VacuumPageMiss, and VacuumSharedCostBalance.

Referenced by autovacuum_do_vac_analyze(), ExecVacuum(), parallel_vacuum_index_is_parallel_safe(), and parallel_vacuum_process_all_indexes().

vacuum_delay_point()

void vacuum_delay_point

(

void

)

Definition at line 2166 of file vacuum.c.

{
    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;
 
        (void) WaitLatch(MyLatch,
                         WL_LATCH_SET | WL_TIMEOUT | WL_EXIT_ON_PM_DEATH,
                         msec,
                         WAIT_EVENT_VACUUM_DELAY);
        ResetLatch(MyLatch);
 
        VacuumCostBalance = 0;
 
        /* update balance values for workers */
        AutoVacuumUpdateDelay();
 
        /* Might have gotten an interrupt while sleeping */
        CHECK_FOR_INTERRUPTS();
    }
}

References AutoVacuumUpdateDelay(), CHECK_FOR_INTERRUPTS, compute_parallel_delay(), InterruptPending, MyLatch, ResetLatch(), VacuumCostActive, VacuumCostBalance, VacuumCostDelay, VacuumCostLimit, VacuumSharedCostBalance, WAIT_EVENT_VACUUM_DELAY, WaitLatch(), WL_EXIT_ON_PM_DEATH, WL_LATCH_SET, and WL_TIMEOUT.

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_scan_skip(), lazy_vacuum_heap_rel(), spgprocesspending(), and spgvacuumpage().

vacuum_is_permitted_for_relation()

bool vacuum_is_permitted_for_relation	(	Oid	relid,
		Form_pg_class	reltuple,
		bits32	options
	)

Definition at line 556 of file vacuum.c.

{
    char       *relname;
    AclMode     mode = 0;
 
    Assert((options & (VACOPT_VACUUM | VACOPT_ANALYZE)) != 0);
 
    /*
     * A role has privileges to vacuum or analyze the relation if any of the
     * following are true:
     *   - the role is a superuser
     *   - the role owns the relation
     *   - the role owns the current database and the relation is not shared
     *   - the role has been granted privileges to vacuum/analyze the relation
     */
    if (options & VACOPT_VACUUM)
        mode |= ACL_VACUUM;
    if (options & VACOPT_ANALYZE)
        mode |= ACL_ANALYZE;
    if (object_ownercheck(RelationRelationId, relid, GetUserId()) ||
        (object_ownercheck(DatabaseRelationId, MyDatabaseId, GetUserId()) && !reltuple->relisshared) ||
        pg_class_aclcheck(relid, GetUserId(), mode) == ACLCHECK_OK)
        return true;
 
    relname = NameStr(reltuple->relname);
 
    if ((options & VACOPT_VACUUM) != 0)
    {
        ereport(WARNING,
                (errmsg("permission denied to vacuum \"%s\", skipping 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)
        ereport(WARNING,
                (errmsg("permission denied to analyze \"%s\", skipping it",
                        relname)));
 
    return false;
}

References ACL_ANALYZE, ACL_VACUUM, ACLCHECK_OK, Assert(), ereport, errmsg(), GetUserId(), mode, MyDatabaseId, NameStr, object_ownercheck(), pg_class_aclcheck(), relname, VACOPT_ANALYZE, VACOPT_VACUUM, and WARNING.

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

vacuum_open_relation()

Relation vacuum_open_relation	(	Oid	relid,
		RangeVar *	relation,
		bits32	options,
		bool	verbose,
		LOCKMODE	lmode
	)

Definition at line 614 of file vacuum.c.

{
    Relation    rel;
    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))
        rel = try_relation_open(relid, lmode);
    else if (ConditionalLockRelationOid(relid, lmode))
        rel = try_relation_open(relid, NoLock);
    else
    {
        rel = NULL;
        rel_lock = false;
    }
 
    /* if relation is opened, leave */
    if (rel)
        return rel;
 
    /*
     * 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;
}

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

Referenced by analyze_rel(), and vacuum_rel().

vacuum_rel()

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

static

Definition at line 1816 of file vacuum.c.

{
    LOCKMODE    lmode;
    Relation    rel;
    LockRelId   lockrelid;
    Oid         toast_relid;
    Oid         save_userid;
    int         save_sec_context;
    int         save_nestlevel;
 
    Assert(params != NULL);
 
    /* Begin a transaction for vacuuming this relation */
    StartTransactionCommand();
 
    if (!(params->options & VACOPT_FULL))
    {
        /*
         * In lazy vacuum, we can set the PROC_IN_VACUUM flag, which lets
         * other concurrent VACUUMs know that they can ignore this one while
         * determining their OldestXmin.  (The reason we don't set it during a
         * full VACUUM is exactly that we may have to run user-defined
         * functions for functional indexes, and we want to make sure that if
         * they use the snapshot set above, any tuples it requires can't get
         * removed from other tables.  An index function that depends on the
         * contents of other tables is arguably broken, but we won't break it
         * here by violating transaction semantics.)
         *
         * We also set the VACUUM_FOR_WRAPAROUND flag, which is passed down by
         * autovacuum; it's used to avoid canceling a vacuum that was invoked
         * in an emergency.
         *
         * Note: these flags remain set until CommitTransaction or
         * AbortTransaction.  We don't want to clear them until we reset
         * MyProc->xid/xmin, otherwise GetOldestNonRemovableTransactionId()
         * might appear to go backwards, which is probably Not Good.  (We also
         * set PROC_IN_VACUUM *before* taking our own snapshot, so that our
         * xmin doesn't become visible ahead of setting the flag.)
         */
        LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
        MyProc->statusFlags |= PROC_IN_VACUUM;
        if (params->is_wraparound)
            MyProc->statusFlags |= PROC_VACUUM_FOR_WRAPAROUND;
        ProcGlobal->statusFlags[MyProc->pgxactoff] = MyProc->statusFlags;
        LWLockRelease(ProcArrayLock);
    }
 
    /*
     * Need to acquire a snapshot to prevent pg_subtrans from being truncated,
     * cutoff xids in local memory wrapping around, and to have updated xmin
     * horizons.
     */
    PushActiveSnapshot(GetTransactionSnapshot());
 
    /*
     * Check for user-requested abort.  Note we want this to be inside a
     * transaction, so xact.c doesn't issue useless WARNING.
     */
    CHECK_FOR_INTERRUPTS();
 
    /*
     * Determine the type of lock we want --- hard exclusive lock for a FULL
     * vacuum, but just ShareUpdateExclusiveLock for concurrent vacuum. Either
     * way, we can be sure that no other backend is vacuuming the same table.
     */
    lmode = (params->options & VACOPT_FULL) ?
        AccessExclusiveLock : ShareUpdateExclusiveLock;
 
    /* open the relation and get the appropriate lock on it */
    rel = vacuum_open_relation(relid, relation, params->options,
                               params->log_min_duration >= 0, lmode);
 
    /* leave if relation could not be opened or locked */
    if (!rel)
    {
        PopActiveSnapshot();
        CommitTransactionCommand();
        return false;
    }
 
    /*
     * Check if relation needs to be skipped based on privileges.  This check
     * happens also when building the relation list to vacuum for a manual
     * operation, and needs to be done additionally here as VACUUM could
     * happen across multiple transactions where privileges could have changed
     * in-between.  Make sure to only generate logs for VACUUM in this case.
     */
    if (!vacuum_is_permitted_for_relation(RelationGetRelid(rel),
                                          rel->rd_rel,
                                          VACOPT_VACUUM))
    {
        relation_close(rel, lmode);
        PopActiveSnapshot();
        CommitTransactionCommand();
        return true;    /* user might have the ANALYZE privilege */
    }
 
    /*
     * Check that it's of a vacuumable relkind.
     */
    if (rel->rd_rel->relkind != RELKIND_RELATION &&
        rel->rd_rel->relkind != RELKIND_MATVIEW &&
        rel->rd_rel->relkind != RELKIND_TOASTVALUE &&
        rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
    {
        ereport(WARNING,
                (errmsg("skipping \"%s\" --- cannot vacuum non-tables or special system tables",
                        RelationGetRelationName(rel))));
        relation_close(rel, lmode);
        PopActiveSnapshot();
        CommitTransactionCommand();
        return false;
    }
 
    /*
     * Silently ignore tables that are temp tables of other backends ---
     * trying to vacuum these will lead to great unhappiness, since their
     * contents are probably not up-to-date on disk.  (We don't throw a
     * warning here; it would just lead to chatter during a database-wide
     * VACUUM.)
     */
    if (RELATION_IS_OTHER_TEMP(rel))
    {
        relation_close(rel, lmode);
        PopActiveSnapshot();
        CommitTransactionCommand();
        return false;
    }
 
    /*
     * Silently ignore partitioned tables as there is no work to be done.  The
     * useful work is on their child partitions, which have been queued up for
     * us separately.
     */
    if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
    {
        relation_close(rel, lmode);
        PopActiveSnapshot();
        CommitTransactionCommand();
        /* It's OK to proceed with ANALYZE on this table */
        return true;
    }
 
    /*
     * Get a session-level lock too. This will protect our access to the
     * relation across multiple transactions, so that we can vacuum the
     * relation's TOAST table (if any) secure in the knowledge that no one is
     * deleting the parent relation.
     *
     * NOTE: this cannot block, even if someone else is waiting for access,
     * because the lock manager knows that both lock requests are from the
     * same process.
     */
    lockrelid = rel->rd_lockInfo.lockRelId;
    LockRelationIdForSession(&lockrelid, lmode);
 
    /*
     * Set index_cleanup option based on index_cleanup reloption if it wasn't
     * specified in VACUUM command, or when running in an autovacuum worker
     */
    if (params->index_cleanup == VACOPTVALUE_UNSPECIFIED)
    {
        StdRdOptIndexCleanup vacuum_index_cleanup;
 
        if (rel->rd_options == NULL)
            vacuum_index_cleanup = STDRD_OPTION_VACUUM_INDEX_CLEANUP_AUTO;
        else
            vacuum_index_cleanup =
                ((StdRdOptions *) rel->rd_options)->vacuum_index_cleanup;
 
        if (vacuum_index_cleanup == STDRD_OPTION_VACUUM_INDEX_CLEANUP_AUTO)
            params->index_cleanup = VACOPTVALUE_AUTO;
        else if (vacuum_index_cleanup == STDRD_OPTION_VACUUM_INDEX_CLEANUP_ON)
            params->index_cleanup = VACOPTVALUE_ENABLED;
        else
        {
            Assert(vacuum_index_cleanup ==
                   STDRD_OPTION_VACUUM_INDEX_CLEANUP_OFF);
            params->index_cleanup = VACOPTVALUE_DISABLED;
        }
    }
 
    /*
     * Set truncate option based on truncate reloption if it wasn't specified
     * in VACUUM command, or when running in an autovacuum worker
     */
    if (params->truncate == VACOPTVALUE_UNSPECIFIED)
    {
        if (rel->rd_options == NULL ||
            ((StdRdOptions *) rel->rd_options)->vacuum_truncate)
            params->truncate = VACOPTVALUE_ENABLED;
        else
            params->truncate = VACOPTVALUE_DISABLED;
    }
 
    /*
     * Remember the relation's TOAST relation for later, if the caller asked
     * us to process it.  In VACUUM FULL, though, the toast table is
     * automatically rebuilt by cluster_rel so we shouldn't recurse to it.
     */
    if ((params->options & VACOPT_PROCESS_TOAST) != 0 &&
        (params->options & VACOPT_FULL) == 0)
        toast_relid = rel->rd_rel->reltoastrelid;
    else
        toast_relid = InvalidOid;
 
    /*
     * Switch to the table owner's userid, so that any index functions are run
     * as that user.  Also lock down security-restricted operations and
     * arrange to make GUC variable changes local to this command. (This is
     * unnecessary, but harmless, for lazy VACUUM.)
     */
    GetUserIdAndSecContext(&save_userid, &save_sec_context);
    SetUserIdAndSecContext(rel->rd_rel->relowner,
                           save_sec_context | SECURITY_RESTRICTED_OPERATION);
    save_nestlevel = NewGUCNestLevel();
 
    /*
     * Do the actual work --- either FULL or "lazy" vacuum
     */
    if (params->options & VACOPT_FULL)
    {
        ClusterParams cluster_params = {0};
 
        /* close relation before vacuuming, but hold lock until commit */
        relation_close(rel, NoLock);
        rel = NULL;
 
        if ((params->options & VACOPT_VERBOSE) != 0)
            cluster_params.options |= CLUOPT_VERBOSE;
 
        /* VACUUM FULL is now a variant of CLUSTER; see cluster.c */
        cluster_rel(relid, InvalidOid, &cluster_params);
    }
    else
        table_relation_vacuum(rel, params, vac_strategy);
 
    /* Roll back any GUC changes executed by index functions */
    AtEOXact_GUC(false, save_nestlevel);
 
    /* Restore userid and security context */
    SetUserIdAndSecContext(save_userid, save_sec_context);
 
    /* all done with this class, but hold lock until commit */
    if (rel)
        relation_close(rel, NoLock);
 
    /*
     * Complete the transaction and free all temporary memory used.
     */
    PopActiveSnapshot();
    CommitTransactionCommand();
 
    /*
     * If the relation has a secondary toast rel, vacuum that too while we
     * still hold the session lock on the main table.  Note however that
     * "analyze" will not get done on the toast table.  This is good, because
     * the toaster always uses hardcoded index access and statistics are
     * totally unimportant for toast relations.
     */
    if (toast_relid != InvalidOid)
        vacuum_rel(toast_relid, NULL, params);
 
    /*
     * Now release the session-level lock on the main table.
     */
    UnlockRelationIdForSession(&lockrelid, lmode);
 
    /* Report that we really did it. */
    return true;
}

References AccessExclusiveLock, Assert(), AtEOXact_GUC(), CHECK_FOR_INTERRUPTS, CLUOPT_VERBOSE, cluster_rel(), CommitTransactionCommand(), ereport, errmsg(), GetTransactionSnapshot(), GetUserIdAndSecContext(), VacuumParams::index_cleanup, InvalidOid, VacuumParams::is_wraparound, LockRelationIdForSession(), LockInfoData::lockRelId, VacuumParams::log_min_duration, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MyProc, NewGUCNestLevel(), NoLock, ClusterParams::options, VacuumParams::options, PGPROC::pgxactoff, PopActiveSnapshot(), PROC_IN_VACUUM, PROC_VACUUM_FOR_WRAPAROUND, ProcGlobal, PushActiveSnapshot(), RelationData::rd_lockInfo, RelationData::rd_options, RelationData::rd_rel, relation_close(), RELATION_IS_OTHER_TEMP, RelationGetRelationName, RelationGetRelid, SECURITY_RESTRICTED_OPERATION, SetUserIdAndSecContext(), ShareUpdateExclusiveLock, StartTransactionCommand(), PGPROC::statusFlags, PROC_HDR::statusFlags, STDRD_OPTION_VACUUM_INDEX_CLEANUP_AUTO, STDRD_OPTION_VACUUM_INDEX_CLEANUP_OFF, STDRD_OPTION_VACUUM_INDEX_CLEANUP_ON, table_relation_vacuum(), VacuumParams::truncate, UnlockRelationIdForSession(), vac_strategy, VACOPT_FULL, VACOPT_PROCESS_TOAST, VACOPT_VACUUM, VACOPT_VERBOSE, VACOPTVALUE_AUTO, VACOPTVALUE_DISABLED, VACOPTVALUE_ENABLED, VACOPTVALUE_UNSPECIFIED, vacuum_is_permitted_for_relation(), vacuum_open_relation(), and WARNING.

Referenced by vacuum().

vacuum_set_xid_limits()

bool vacuum_set_xid_limits	(	Relation	rel,
		const VacuumParams *	params,
		TransactionId *	OldestXmin,
		MultiXactId *	OldestMxact,
		TransactionId *	FreezeLimit,
		MultiXactId *	MultiXactCutoff
	)

Definition at line 940 of file vacuum.c.

{
    int         freeze_min_age,
                multixact_freeze_min_age,
                freeze_table_age,
                multixact_freeze_table_age,
                effective_multixact_freeze_max_age;
    TransactionId nextXID,
                safeOldestXmin,
                aggressiveXIDCutoff;
    MultiXactId nextMXID,
                safeOldestMxact,
                aggressiveMXIDCutoff;
 
    /* Use mutable copies of freeze age parameters */
    freeze_min_age = params->freeze_min_age;
    multixact_freeze_min_age = params->multixact_freeze_min_age;
    freeze_table_age = params->freeze_table_age;
    multixact_freeze_table_age = params->multixact_freeze_table_age;
 
    /*
     * Acquire OldestXmin.
     *
     * 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 (usually no
     * XID assigned), 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));
 
    /* Acquire OldestMxact */
    *OldestMxact = GetOldestMultiXactId();
    Assert(MultiXactIdIsValid(*OldestMxact));
 
    /* Acquire next XID/next MXID values used to apply age-based settings */
    nextXID = ReadNextTransactionId();
    nextMXID = ReadNextMultiXactId();
 
    /*
     * 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.
     */
    if (freeze_min_age < 0)
        freeze_min_age = vacuum_freeze_min_age;
    freeze_min_age = Min(freeze_min_age, autovacuum_freeze_max_age / 2);
    Assert(freeze_min_age >= 0);
 
    /* Compute FreezeLimit, being careful to generate a normal XID */
    *FreezeLimit = nextXID - freeze_min_age;
    if (!TransactionIdIsNormal(*FreezeLimit))
        *FreezeLimit = FirstNormalTransactionId;
    /* FreezeLimit must always be <= OldestXmin */
    if (TransactionIdPrecedes(*OldestXmin, *FreezeLimit))
        *FreezeLimit = *OldestXmin;
 
    /*
     * 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.
     */
    if (multixact_freeze_min_age < 0)
        multixact_freeze_min_age = vacuum_multixact_freeze_min_age;
    multixact_freeze_min_age = Min(multixact_freeze_min_age,
                                   effective_multixact_freeze_max_age / 2);
    Assert(multixact_freeze_min_age >= 0);
 
    /* Compute MultiXactCutoff, being careful to generate a valid value */
    *MultiXactCutoff = nextMXID - multixact_freeze_min_age;
    if (*MultiXactCutoff < FirstMultiXactId)
        *MultiXactCutoff = FirstMultiXactId;
    /* MultiXactCutoff must always be <= OldestMxact */
    if (MultiXactIdPrecedes(*OldestMxact, *MultiXactCutoff))
        *MultiXactCutoff = *OldestMxact;
 
    /*
     * Done setting output parameters; check if OldestXmin or OldestMxact are
     * held back to an unsafe degree in passing
     */
    safeOldestXmin = nextXID - autovacuum_freeze_max_age;
    if (!TransactionIdIsNormal(safeOldestXmin))
        safeOldestXmin = FirstNormalTransactionId;
    safeOldestMxact = nextMXID - effective_multixact_freeze_max_age;
    if (safeOldestMxact < FirstMultiXactId)
        safeOldestMxact = FirstMultiXactId;
    if (TransactionIdPrecedes(*OldestXmin, safeOldestXmin))
        ereport(WARNING,
                (errmsg("cutoff for removing and freezing tuples 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.")));
    if (MultiXactIdPrecedes(*OldestMxact, safeOldestMxact))
        ereport(WARNING,
                (errmsg("cutoff for freezing multixacts 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.")));
 
    /*
     * Finally, figure out if caller needs to do an aggressive VACUUM or not.
     *
     * Determine the table freeze age to use: as specified by the caller, or
     * the value of the vacuum_freeze_table_age GUC, 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 XIDs before
     * anti-wraparound autovacuum is launched.
     */
    if (freeze_table_age < 0)
        freeze_table_age = vacuum_freeze_table_age;
    freeze_table_age = Min(freeze_table_age, autovacuum_freeze_max_age * 0.95);
    Assert(freeze_table_age >= 0);
    aggressiveXIDCutoff = nextXID - freeze_table_age;
    if (!TransactionIdIsNormal(aggressiveXIDCutoff))
        aggressiveXIDCutoff = FirstNormalTransactionId;
    if (TransactionIdPrecedesOrEquals(rel->rd_rel->relfrozenxid,
                                      aggressiveXIDCutoff))
        return true;
 
    /*
     * Similar to the above, determine the table freeze age to use for
     * multixacts: as specified by the caller, or the value of the
     * vacuum_multixact_freeze_table_age GUC, but in any case not more than
     * effective_multixact_freeze_max_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.
     */
    if (multixact_freeze_table_age < 0)
        multixact_freeze_table_age = vacuum_multixact_freeze_table_age;
    multixact_freeze_table_age =
        Min(multixact_freeze_table_age,
            effective_multixact_freeze_max_age * 0.95);
    Assert(multixact_freeze_table_age >= 0);
    aggressiveMXIDCutoff = nextMXID - multixact_freeze_table_age;
    if (aggressiveMXIDCutoff < FirstMultiXactId)
        aggressiveMXIDCutoff = FirstMultiXactId;
    if (MultiXactIdPrecedesOrEquals(rel->rd_rel->relminmxid,
                                    aggressiveMXIDCutoff))
        return true;
 
    /* Non-aggressive VACUUM */
    return false;
}

References Assert(), autovacuum_freeze_max_age, ereport, errhint(), errmsg(), FirstMultiXactId, FirstNormalTransactionId, VacuumParams::freeze_min_age, VacuumParams::freeze_table_age, GetOldestMultiXactId(), GetOldestNonRemovableTransactionId(), Min, VacuumParams::multixact_freeze_min_age, VacuumParams::multixact_freeze_table_age, MultiXactIdIsValid, MultiXactIdPrecedes(), MultiXactIdPrecedesOrEquals(), MultiXactMemberFreezeThreshold(), OldSnapshotThresholdActive(), RelationData::rd_rel, ReadNextMultiXactId(), ReadNextTransactionId(), SetOldSnapshotThresholdTimestamp(), TransactionIdIsNormal, TransactionIdLimitedForOldSnapshots(), TransactionIdPrecedes(), TransactionIdPrecedesOrEquals(), 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().

vacuum_xid_failsafe_check()

bool vacuum_xid_failsafe_check	(	TransactionId	relfrozenxid,
		MultiXactId	relminmxid
	)

Definition at line 1126 of file vacuum.c.

{
    TransactionId xid_skip_limit;
    MultiXactId multi_skip_limit;
    int         skip_index_vacuum;
 
    Assert(TransactionIdIsNormal(relfrozenxid));
    Assert(MultiXactIdIsValid(relminmxid));
 
    /*
     * Determine the index skipping age to use. In any case no less than
     * autovacuum_freeze_max_age * 1.05.
     */
    skip_index_vacuum = Max(vacuum_failsafe_age, autovacuum_freeze_max_age * 1.05);
 
    xid_skip_limit = ReadNextTransactionId() - skip_index_vacuum;
    if (!TransactionIdIsNormal(xid_skip_limit))
        xid_skip_limit = FirstNormalTransactionId;
 
    if (TransactionIdPrecedes(relfrozenxid, xid_skip_limit))
    {
        /* The table's relfrozenxid is too old */
        return true;
    }
 
    /*
     * Similar to above, determine the index skipping age to use for
     * multixact. In any case no less than autovacuum_multixact_freeze_max_age *
     * 1.05.
     */
    skip_index_vacuum = Max(vacuum_multixact_failsafe_age,
                            autovacuum_multixact_freeze_max_age * 1.05);
 
    multi_skip_limit = ReadNextMultiXactId() - skip_index_vacuum;
    if (multi_skip_limit < FirstMultiXactId)
        multi_skip_limit = FirstMultiXactId;
 
    if (MultiXactIdPrecedes(relminmxid, multi_skip_limit))
    {
        /* The table's relminmxid is too old */
        return true;
    }
 
    return false;
}

References Assert(), autovacuum_freeze_max_age, autovacuum_multixact_freeze_max_age, FirstMultiXactId, FirstNormalTransactionId, Max, MultiXactIdIsValid, MultiXactIdPrecedes(), ReadNextMultiXactId(), ReadNextTransactionId(), TransactionIdIsNormal, TransactionIdPrecedes(), vacuum_failsafe_age, and vacuum_multixact_failsafe_age.

Referenced by lazy_check_wraparound_failsafe().

Variable Documentation

vac_context

MemoryContext vac_context = NULL

static

Definition at line 75 of file vacuum.c.

Referenced by expand_vacuum_rel(), get_all_vacuum_rels(), and vacuum().

vac_strategy

BufferAccessStrategy vac_strategy

static

Definition at line 76 of file vacuum.c.

Referenced by vacuum(), and vacuum_rel().

vacuum_failsafe_age

int vacuum_failsafe_age

Definition at line 70 of file vacuum.c.

Referenced by vacuum_xid_failsafe_check().

vacuum_freeze_min_age

int vacuum_freeze_min_age

Definition at line 66 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 67 of file vacuum.c.

Referenced by do_autovacuum(), and vacuum_set_xid_limits().

vacuum_multixact_failsafe_age

int vacuum_multixact_failsafe_age

Definition at line 71 of file vacuum.c.

Referenced by vacuum_xid_failsafe_check().

vacuum_multixact_freeze_min_age

int vacuum_multixact_freeze_min_age

Definition at line 68 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 69 of file vacuum.c.

Referenced by do_autovacuum(), and vacuum_set_xid_limits().

VacuumActiveNWorkers

pg_atomic_uint32* VacuumActiveNWorkers = NULL

Definition at line 84 of file vacuum.c.

Referenced by compute_parallel_delay(), parallel_vacuum_main(), parallel_vacuum_process_all_indexes(), parallel_vacuum_process_safe_indexes(), parallel_vacuum_process_unsafe_indexes(), and vacuum().

VacuumCostBalanceLocal

int VacuumCostBalanceLocal = 0

Definition at line 85 of file vacuum.c.

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

VacuumSharedCostBalance

pg_atomic_uint32* VacuumSharedCostBalance = NULL

Definition at line 83 of file vacuum.c.

Referenced by compute_parallel_delay(), parallel_vacuum_main(), parallel_vacuum_process_all_indexes(), vacuum(), and vacuum_delay_point().