nbtree.c File Reference

#include "postgres.h"
#include "access/nbtree.h"
#include "access/relscan.h"
#include "access/xlog.h"
#include "catalog/index.h"
#include "commands/vacuum.h"
#include "pgstat.h"
#include "storage/condition_variable.h"
#include "storage/indexfsm.h"
#include "storage/ipc.h"
#include "storage/lmgr.h"
#include "storage/smgr.h"
#include "tcop/tcopprot.h"
#include "utils/builtins.h"
#include "utils/index_selfuncs.h"
#include "utils/memutils.h"

Include dependency graph for nbtree.c:

Go to the source code of this file.

Data Structures
struct	BTBuildState
struct	BTVacState
struct	BTParallelScanDescData

Typedefs
typedef struct BTParallelScanDescData	BTParallelScanDescData
typedef struct BTParallelScanDescData *	BTParallelScanDesc

Enumerations
enum	BTPS_State { BTPARALLEL_NOT_INITIALIZED, BTPARALLEL_ADVANCING, BTPARALLEL_IDLE, BTPARALLEL_DONE }

Functions
static void	btbuildCallback (Relation index, HeapTuple htup, Datum *values, bool *isnull, bool tupleIsAlive, void *state)
static void	btvacuumscan (IndexVacuumInfo *info, IndexBulkDeleteResult *stats, IndexBulkDeleteCallback callback, void *callback_state, BTCycleId cycleid)
static void	btvacuumpage (BTVacState *vstate, BlockNumber blkno, BlockNumber orig_blkno)
Datum	bthandler (PG_FUNCTION_ARGS)
IndexBuildResult *	btbuild (Relation heap, Relation index, IndexInfo *indexInfo)
void	btbuildempty (Relation index)
bool	btinsert (Relation rel, Datum *values, bool *isnull, ItemPointer ht_ctid, Relation heapRel, IndexUniqueCheck checkUnique, IndexInfo *indexInfo)
bool	btgettuple (IndexScanDesc scan, ScanDirection dir)
int64	btgetbitmap (IndexScanDesc scan, TIDBitmap *tbm)
IndexScanDesc	btbeginscan (Relation rel, int nkeys, int norderbys)
void	btrescan (IndexScanDesc scan, ScanKey scankey, int nscankeys, ScanKey orderbys, int norderbys)
void	btendscan (IndexScanDesc scan)
void	btmarkpos (IndexScanDesc scan)
void	btrestrpos (IndexScanDesc scan)
Size	btestimateparallelscan (void)
void	btinitparallelscan (void *target)
void	btparallelrescan (IndexScanDesc scan)
bool	_bt_parallel_seize (IndexScanDesc scan, BlockNumber *pageno)
void	_bt_parallel_release (IndexScanDesc scan, BlockNumber scan_page)
void	_bt_parallel_done (IndexScanDesc scan)
void	_bt_parallel_advance_array_keys (IndexScanDesc scan)
IndexBulkDeleteResult *	btbulkdelete (IndexVacuumInfo *info, IndexBulkDeleteResult *stats, IndexBulkDeleteCallback callback, void *callback_state)
IndexBulkDeleteResult *	btvacuumcleanup (IndexVacuumInfo *info, IndexBulkDeleteResult *stats)
bool	btcanreturn (Relation index, int attno)

Typedef Documentation

typedef struct BTParallelScanDescData* BTParallelScanDesc

Definition at line 104 of file nbtree.c.

typedef struct BTParallelScanDescData BTParallelScanDescData

Enumeration Type Documentation

enum BTPS_State

Enumerator
BTPARALLEL_NOT_INITIALIZED
BTPARALLEL_ADVANCING
BTPARALLEL_IDLE
BTPARALLEL_DONE

Definition at line 80 of file nbtree.c.

{
    BTPARALLEL_NOT_INITIALIZED,
    BTPARALLEL_ADVANCING,
    BTPARALLEL_IDLE,
    BTPARALLEL_DONE
} BTPS_State;

Function Documentation

void _bt_parallel_advance_array_keys

(

IndexScanDesc

scan

)

Definition at line 888 of file nbtree.c.

References BTScanOpaqueData::arrayKeyCount, BTPARALLEL_DONE, BTPARALLEL_NOT_INITIALIZED, InvalidBlockNumber, OffsetToPointer, IndexScanDescData::opaque, IndexScanDescData::parallel_scan, SpinLockAcquire, and SpinLockRelease.

Referenced by _bt_advance_array_keys().

{
    BTScanOpaque so = (BTScanOpaque) scan->opaque;
    ParallelIndexScanDesc parallel_scan = scan->parallel_scan;
    BTParallelScanDesc btscan;

    btscan = (BTParallelScanDesc) OffsetToPointer((void *) parallel_scan,
                                                  parallel_scan->ps_offset);

    so->arrayKeyCount++;
    SpinLockAcquire(&btscan->btps_mutex);
    if (btscan->btps_pageStatus == BTPARALLEL_DONE)
    {
        btscan->btps_scanPage = InvalidBlockNumber;
        btscan->btps_pageStatus = BTPARALLEL_NOT_INITIALIZED;
        btscan->btps_arrayKeyCount++;
    }
    SpinLockRelease(&btscan->btps_mutex);
}

void _bt_parallel_done

(

IndexScanDesc

scan

)

Definition at line 847 of file nbtree.c.

References BTScanOpaqueData::arrayKeyCount, BTPARALLEL_DONE, ConditionVariableBroadcast(), NULL, OffsetToPointer, IndexScanDescData::opaque, IndexScanDescData::parallel_scan, SpinLockAcquire, and SpinLockRelease.

Referenced by _bt_first(), and _bt_readnextpage().

{
    BTScanOpaque so = (BTScanOpaque) scan->opaque;
    ParallelIndexScanDesc parallel_scan = scan->parallel_scan;
    BTParallelScanDesc btscan;
    bool        status_changed = false;

    /* Do nothing, for non-parallel scans */
    if (parallel_scan == NULL)
        return;

    btscan = (BTParallelScanDesc) OffsetToPointer((void *) parallel_scan,
                                                  parallel_scan->ps_offset);

    /*
     * Mark the parallel scan as done for this combination of scan keys,
     * unless some other process already did so.  See also
     * _bt_advance_array_keys.
     */
    SpinLockAcquire(&btscan->btps_mutex);
    if (so->arrayKeyCount >= btscan->btps_arrayKeyCount &&
        btscan->btps_pageStatus != BTPARALLEL_DONE)
    {
        btscan->btps_pageStatus = BTPARALLEL_DONE;
        status_changed = true;
    }
    SpinLockRelease(&btscan->btps_mutex);

    /* wake up all the workers associated with this parallel scan */
    if (status_changed)
        ConditionVariableBroadcast(&btscan->btps_cv);
}

void _bt_parallel_release	(	IndexScanDesc	scan,
		BlockNumber	scan_page
	)

Definition at line 824 of file nbtree.c.

References BTPARALLEL_IDLE, BTParallelScanDescData::btps_cv, BTParallelScanDescData::btps_mutex, BTParallelScanDescData::btps_pageStatus, BTParallelScanDescData::btps_scanPage, ConditionVariableSignal(), OffsetToPointer, IndexScanDescData::parallel_scan, ParallelIndexScanDescData::ps_offset, SpinLockAcquire, and SpinLockRelease.

Referenced by _bt_readpage().

{
    ParallelIndexScanDesc parallel_scan = scan->parallel_scan;
    BTParallelScanDesc btscan;

    btscan = (BTParallelScanDesc) OffsetToPointer((void *) parallel_scan,
                                                  parallel_scan->ps_offset);

    SpinLockAcquire(&btscan->btps_mutex);
    btscan->btps_scanPage = scan_page;
    btscan->btps_pageStatus = BTPARALLEL_IDLE;
    SpinLockRelease(&btscan->btps_mutex);
    ConditionVariableSignal(&btscan->btps_cv);
}

bool _bt_parallel_seize	(	IndexScanDesc	scan,
		BlockNumber *	pageno
	)

Definition at line 766 of file nbtree.c.

References BTScanOpaqueData::arrayKeyCount, BTPARALLEL_ADVANCING, BTPARALLEL_DONE, ConditionVariableCancelSleep(), ConditionVariableSleep(), OffsetToPointer, IndexScanDescData::opaque, P_NONE, IndexScanDescData::parallel_scan, SpinLockAcquire, SpinLockRelease, status(), and WAIT_EVENT_BTREE_PAGE.

Referenced by _bt_first(), _bt_readnextpage(), and _bt_steppage().

{
    BTScanOpaque so = (BTScanOpaque) scan->opaque;
    BTPS_State  pageStatus;
    bool        exit_loop = false;
    bool        status = true;
    ParallelIndexScanDesc parallel_scan = scan->parallel_scan;
    BTParallelScanDesc btscan;

    *pageno = P_NONE;

    btscan = (BTParallelScanDesc) OffsetToPointer((void *) parallel_scan,
                                                  parallel_scan->ps_offset);

    while (1)
    {
        SpinLockAcquire(&btscan->btps_mutex);
        pageStatus = btscan->btps_pageStatus;

        if (so->arrayKeyCount < btscan->btps_arrayKeyCount)
        {
            /* Parallel scan has already advanced to a new set of scankeys. */
            status = false;
        }
        else if (pageStatus == BTPARALLEL_DONE)
        {
            /*
             * We're done with this set of scankeys.  This may be the end, or
             * there could be more sets to try.
             */
            status = false;
        }
        else if (pageStatus != BTPARALLEL_ADVANCING)
        {
            /*
             * We have successfully seized control of the scan for the purpose
             * of advancing it to a new page!
             */
            btscan->btps_pageStatus = BTPARALLEL_ADVANCING;
            *pageno = btscan->btps_scanPage;
            exit_loop = true;
        }
        SpinLockRelease(&btscan->btps_mutex);
        if (exit_loop || !status)
            break;
        ConditionVariableSleep(&btscan->btps_cv, WAIT_EVENT_BTREE_PAGE);
    }
    ConditionVariableCancelSleep();

    return status;
}

IndexScanDesc btbeginscan	(	Relation	rel,
		int	nkeys,
		int	norderbys
	)

Definition at line 473 of file nbtree.c.

References BTScanOpaqueData::arrayContext, BTScanOpaqueData::arrayKeyData, BTScanOpaqueData::arrayKeys, Assert, BTScanPosInvalidate, BTScanOpaqueData::currPos, BTScanOpaqueData::currTuples, BTScanOpaqueData::keyData, BTScanOpaqueData::killedItems, BTScanOpaqueData::markPos, BTScanOpaqueData::markTuples, NULL, BTScanOpaqueData::numArrayKeys, IndexScanDescData::numberOfKeys, BTScanOpaqueData::numKilled, IndexScanDescData::opaque, palloc(), RelationGetDescr, RelationGetIndexScan(), and IndexScanDescData::xs_itupdesc.

Referenced by bthandler().

{
    IndexScanDesc scan;
    BTScanOpaque so;

    /* no order by operators allowed */
    Assert(norderbys == 0);

    /* get the scan */
    scan = RelationGetIndexScan(rel, nkeys, norderbys);

    /* allocate private workspace */
    so = (BTScanOpaque) palloc(sizeof(BTScanOpaqueData));
    BTScanPosInvalidate(so->currPos);
    BTScanPosInvalidate(so->markPos);
    if (scan->numberOfKeys > 0)
        so->keyData = (ScanKey) palloc(scan->numberOfKeys * sizeof(ScanKeyData));
    else
        so->keyData = NULL;

    so->arrayKeyData = NULL;    /* assume no array keys for now */
    so->numArrayKeys = 0;
    so->arrayKeys = NULL;
    so->arrayContext = NULL;

    so->killedItems = NULL;     /* until needed */
    so->numKilled = 0;

    /*
     * We don't know yet whether the scan will be index-only, so we do not
     * allocate the tuple workspace arrays until btrescan.  However, we set up
     * scan->xs_itupdesc whether we'll need it or not, since that's so cheap.
     */
    so->currTuples = so->markTuples = NULL;

    scan->xs_itupdesc = RelationGetDescr(rel);

    scan->opaque = so;

    return scan;
}

IndexBuildResult* btbuild	(	Relation	heap,
		Relation	index,
		IndexInfo *	indexInfo
	)

Definition at line 173 of file nbtree.c.

References _bt_leafbuild(), _bt_spooldestroy(), _bt_spoolinit(), btbuildCallback(), elog, ERROR, BTBuildState::haveDead, IndexBuildResult::heap_tuples, BTBuildState::heapRel, IndexInfo::ii_Unique, IndexBuildResult::index_tuples, IndexBuildHeapScan(), BTBuildState::indtuples, BTBuildState::isUnique, log_btree_build_stats, NULL, palloc(), RelationGetNumberOfBlocks, RelationGetRelationName, ResetUsage(), result, ShowUsage(), BTBuildState::spool, and BTBuildState::spool2.

Referenced by bthandler().

{
    IndexBuildResult *result;
    double      reltuples;
    BTBuildState buildstate;

    buildstate.isUnique = indexInfo->ii_Unique;
    buildstate.haveDead = false;
    buildstate.heapRel = heap;
    buildstate.spool = NULL;
    buildstate.spool2 = NULL;
    buildstate.indtuples = 0;

#ifdef BTREE_BUILD_STATS
    if (log_btree_build_stats)
        ResetUsage();
#endif                          /* BTREE_BUILD_STATS */

    /*
     * We expect to be called exactly once for any index relation. If that's
     * not the case, big trouble's what we have.
     */
    if (RelationGetNumberOfBlocks(index) != 0)
        elog(ERROR, "index \"%s\" already contains data",
             RelationGetRelationName(index));

    buildstate.spool = _bt_spoolinit(heap, index, indexInfo->ii_Unique, false);

    /*
     * If building a unique index, put dead tuples in a second spool to keep
     * them out of the uniqueness check.
     */
    if (indexInfo->ii_Unique)
        buildstate.spool2 = _bt_spoolinit(heap, index, false, true);

    /* do the heap scan */
    reltuples = IndexBuildHeapScan(heap, index, indexInfo, true,
                                   btbuildCallback, (void *) &buildstate);

    /* okay, all heap tuples are indexed */
    if (buildstate.spool2 && !buildstate.haveDead)
    {
        /* spool2 turns out to be unnecessary */
        _bt_spooldestroy(buildstate.spool2);
        buildstate.spool2 = NULL;
    }

    /*
     * Finish the build by (1) completing the sort of the spool file, (2)
     * inserting the sorted tuples into btree pages and (3) building the upper
     * levels.
     */
    _bt_leafbuild(buildstate.spool, buildstate.spool2);
    _bt_spooldestroy(buildstate.spool);
    if (buildstate.spool2)
        _bt_spooldestroy(buildstate.spool2);

#ifdef BTREE_BUILD_STATS
    if (log_btree_build_stats)
    {
        ShowUsage("BTREE BUILD STATS");
        ResetUsage();
    }
#endif                          /* BTREE_BUILD_STATS */

    /*
     * Return statistics
     */
    result = (IndexBuildResult *) palloc(sizeof(IndexBuildResult));

    result->heap_tuples = reltuples;
    result->index_tuples = buildstate.indtuples;

    return result;
}

static void btbuildCallback ( Relation  index, HeapTuple  htup, Datum *  values, bool *  isnull, bool  tupleIsAlive, void *  state  )

static

Definition at line 253 of file nbtree.c.

References _bt_spool(), BTBuildState::haveDead, BTBuildState::indtuples, NULL, BTBuildState::spool, BTBuildState::spool2, and HeapTupleData::t_self.

Referenced by btbuild().

{
    BTBuildState *buildstate = (BTBuildState *) state;

    /*
     * insert the index tuple into the appropriate spool file for subsequent
     * processing
     */
    if (tupleIsAlive || buildstate->spool2 == NULL)
        _bt_spool(buildstate->spool, &htup->t_self, values, isnull);
    else
    {
        /* dead tuples are put into spool2 */
        buildstate->haveDead = true;
        _bt_spool(buildstate->spool2, &htup->t_self, values, isnull);
    }

    buildstate->indtuples += 1;
}

void btbuildempty

(

Relation

index

)

Definition at line 282 of file nbtree.c.

References _bt_initmetapage(), BTREE_METAPAGE, INIT_FORKNUM, log_newpage(), RelFileNodeBackend::node, P_NONE, PageSetChecksumInplace(), palloc(), RelationData::rd_smgr, SMgrRelationData::smgr_rnode, smgrimmedsync(), and smgrwrite().

Referenced by bthandler().

{
    Page        metapage;

    /* Construct metapage. */
    metapage = (Page) palloc(BLCKSZ);
    _bt_initmetapage(metapage, P_NONE, 0);

    /*
     * Write the page and log it.  It might seem that an immediate sync would
     * be sufficient to guarantee that the file exists on disk, but recovery
     * itself might remove it while replaying, for example, an
     * XLOG_DBASE_CREATE or XLOG_TBLSPC_CREATE record.  Therefore, we need
     * this even when wal_level=minimal.
     */
    PageSetChecksumInplace(metapage, BTREE_METAPAGE);
    smgrwrite(index->rd_smgr, INIT_FORKNUM, BTREE_METAPAGE,
              (char *) metapage, true);
    log_newpage(&index->rd_smgr->smgr_rnode.node, INIT_FORKNUM,
                BTREE_METAPAGE, metapage, false);

    /*
     * An immediate sync is required even if we xlog'd the page, because the
     * write did not go through shared_buffers and therefore a concurrent
     * checkpoint may have moved the redo pointer past our xlog record.
     */
    smgrimmedsync(index->rd_smgr, INIT_FORKNUM);
}

IndexBulkDeleteResult* btbulkdelete	(	IndexVacuumInfo *	info,
		IndexBulkDeleteResult *	stats,
		IndexBulkDeleteCallback	callback,
		void *	callback_state
	)

Definition at line 916 of file nbtree.c.

References _bt_end_vacuum(), _bt_end_vacuum_callback(), _bt_start_vacuum(), btvacuumscan(), IndexVacuumInfo::index, NULL, palloc0(), PG_END_ENSURE_ERROR_CLEANUP, PG_ENSURE_ERROR_CLEANUP, and PointerGetDatum.

Referenced by bthandler().

{
    Relation    rel = info->index;
    BTCycleId   cycleid;

    /* allocate stats if first time through, else re-use existing struct */
    if (stats == NULL)
        stats = (IndexBulkDeleteResult *) palloc0(sizeof(IndexBulkDeleteResult));

    /* Establish the vacuum cycle ID to use for this scan */
    /* The ENSURE stuff ensures we clean up shared memory on failure */
    PG_ENSURE_ERROR_CLEANUP(_bt_end_vacuum_callback, PointerGetDatum(rel));
    {
        cycleid = _bt_start_vacuum(rel);

        btvacuumscan(info, stats, callback, callback_state, cycleid);
    }
    PG_END_ENSURE_ERROR_CLEANUP(_bt_end_vacuum_callback, PointerGetDatum(rel));
    _bt_end_vacuum(rel);

    return stats;
}

bool btcanreturn	(	Relation	index,
		int	attno
	)

Definition at line 1389 of file nbtree.c.

Referenced by bthandler().

{
    return true;
}

void btendscan

(

IndexScanDesc

scan

)

Definition at line 579 of file nbtree.c.

References _bt_killitems(), BTScanOpaqueData::arrayContext, BTScanPosIsValid, BTScanPosUnpinIfPinned, BTScanOpaqueData::currPos, BTScanOpaqueData::currTuples, BTScanOpaqueData::keyData, BTScanOpaqueData::killedItems, BTScanOpaqueData::markItemIndex, BTScanOpaqueData::markPos, MemoryContextDelete(), NULL, BTScanOpaqueData::numKilled, IndexScanDescData::opaque, and pfree().

Referenced by bthandler().

{
    BTScanOpaque so = (BTScanOpaque) scan->opaque;

    /* we aren't holding any read locks, but gotta drop the pins */
    if (BTScanPosIsValid(so->currPos))
    {
        /* Before leaving current page, deal with any killed items */
        if (so->numKilled > 0)
            _bt_killitems(scan);
        BTScanPosUnpinIfPinned(so->currPos);
    }

    so->markItemIndex = -1;
    BTScanPosUnpinIfPinned(so->markPos);

    /* No need to invalidate positions, the RAM is about to be freed. */

    /* Release storage */
    if (so->keyData != NULL)
        pfree(so->keyData);
    /* so->arrayKeyData and so->arrayKeys are in arrayContext */
    if (so->arrayContext != NULL)
        MemoryContextDelete(so->arrayContext);
    if (so->killedItems != NULL)
        pfree(so->killedItems);
    if (so->currTuples != NULL)
        pfree(so->currTuples);
    /* so->markTuples should not be pfree'd, see btrescan */
    pfree(so);
}

Size btestimateparallelscan

(

void

)

Definition at line 701 of file nbtree.c.

Referenced by bthandler().

{
    return sizeof(BTParallelScanDescData);
}

int64 btgetbitmap	(	IndexScanDesc	scan,
		TIDBitmap *	tbm
	)

Definition at line 415 of file nbtree.c.

References _bt_advance_array_keys(), _bt_first(), _bt_next(), _bt_start_array_keys(), BTScanOpaqueData::currPos, ForwardScanDirection, BTScanPosItem::heapTid, BTScanPosData::itemIndex, BTScanPosData::items, BTScanPosData::lastItem, BTScanOpaqueData::numArrayKeys, IndexScanDescData::opaque, HeapTupleData::t_self, tbm_add_tuples(), and IndexScanDescData::xs_ctup.

Referenced by bthandler().

{
    BTScanOpaque so = (BTScanOpaque) scan->opaque;
    int64       ntids = 0;
    ItemPointer heapTid;

    /*
     * If we have any array keys, initialize them.
     */
    if (so->numArrayKeys)
    {
        /* punt if we have any unsatisfiable array keys */
        if (so->numArrayKeys < 0)
            return ntids;

        _bt_start_array_keys(scan, ForwardScanDirection);
    }

    /* This loop handles advancing to the next array elements, if any */
    do
    {
        /* Fetch the first page & tuple */
        if (_bt_first(scan, ForwardScanDirection))
        {
            /* Save tuple ID, and continue scanning */
            heapTid = &scan->xs_ctup.t_self;
            tbm_add_tuples(tbm, heapTid, 1, false);
            ntids++;

            for (;;)
            {
                /*
                 * Advance to next tuple within page.  This is the same as the
                 * easy case in _bt_next().
                 */
                if (++so->currPos.itemIndex > so->currPos.lastItem)
                {
                    /* let _bt_next do the heavy lifting */
                    if (!_bt_next(scan, ForwardScanDirection))
                        break;
                }

                /* Save tuple ID, and continue scanning */
                heapTid = &so->currPos.items[so->currPos.itemIndex].heapTid;
                tbm_add_tuples(tbm, heapTid, 1, false);
                ntids++;
            }
        }
        /* Now see if we have more array keys to deal with */
    } while (so->numArrayKeys && _bt_advance_array_keys(scan, ForwardScanDirection));

    return ntids;
}

bool btgettuple	(	IndexScanDesc	scan,
		ScanDirection	dir
	)

Definition at line 341 of file nbtree.c.

References _bt_advance_array_keys(), _bt_first(), _bt_next(), _bt_start_array_keys(), BTScanPosIsValid, BTScanOpaqueData::currPos, BTScanPosData::itemIndex, IndexScanDescData::kill_prior_tuple, BTScanOpaqueData::killedItems, MaxIndexTuplesPerPage, NULL, BTScanOpaqueData::numArrayKeys, BTScanOpaqueData::numKilled, IndexScanDescData::opaque, palloc(), and IndexScanDescData::xs_recheck.

Referenced by bthandler().

{
    BTScanOpaque so = (BTScanOpaque) scan->opaque;
    bool        res;

    /* btree indexes are never lossy */
    scan->xs_recheck = false;

    /*
     * If we have any array keys, initialize them during first call for a
     * scan.  We can't do this in btrescan because we don't know the scan
     * direction at that time.
     */
    if (so->numArrayKeys && !BTScanPosIsValid(so->currPos))
    {
        /* punt if we have any unsatisfiable array keys */
        if (so->numArrayKeys < 0)
            return false;

        _bt_start_array_keys(scan, dir);
    }

    /* This loop handles advancing to the next array elements, if any */
    do
    {
        /*
         * If we've already initialized this scan, we can just advance it in
         * the appropriate direction.  If we haven't done so yet, we call
         * _bt_first() to get the first item in the scan.
         */
        if (!BTScanPosIsValid(so->currPos))
            res = _bt_first(scan, dir);
        else
        {
            /*
             * Check to see if we should kill the previously-fetched tuple.
             */
            if (scan->kill_prior_tuple)
            {
                /*
                 * Yes, remember it for later. (We'll deal with all such
                 * tuples at once right before leaving the index page.)  The
                 * test for numKilled overrun is not just paranoia: if the
                 * caller reverses direction in the indexscan then the same
                 * item might get entered multiple times. It's not worth
                 * trying to optimize that, so we don't detect it, but instead
                 * just forget any excess entries.
                 */
                if (so->killedItems == NULL)
                    so->killedItems = (int *)
                        palloc(MaxIndexTuplesPerPage * sizeof(int));
                if (so->numKilled < MaxIndexTuplesPerPage)
                    so->killedItems[so->numKilled++] = so->currPos.itemIndex;
            }

            /*
             * Now continue the scan.
             */
            res = _bt_next(scan, dir);
        }

        /* If we have a tuple, return it ... */
        if (res)
            break;
        /* ... otherwise see if we have more array keys to deal with */
    } while (so->numArrayKeys && _bt_advance_array_keys(scan, dir));

    return res;
}

Datum bthandler

(

PG_FUNCTION_ARGS

)

Definition at line 125 of file nbtree.c.

References IndexAmRoutine::ambeginscan, IndexAmRoutine::ambuild, IndexAmRoutine::ambuildempty, IndexAmRoutine::ambulkdelete, IndexAmRoutine::amcanbackward, IndexAmRoutine::amcanmulticol, IndexAmRoutine::amcanorder, IndexAmRoutine::amcanorderbyop, IndexAmRoutine::amcanparallel, IndexAmRoutine::amcanreturn, IndexAmRoutine::amcanunique, IndexAmRoutine::amclusterable, IndexAmRoutine::amcostestimate, IndexAmRoutine::amendscan, IndexAmRoutine::amestimateparallelscan, IndexAmRoutine::amgetbitmap, IndexAmRoutine::amgettuple, IndexAmRoutine::aminitparallelscan, IndexAmRoutine::aminsert, IndexAmRoutine::amkeytype, IndexAmRoutine::ammarkpos, IndexAmRoutine::amoptionalkey, IndexAmRoutine::amoptions, IndexAmRoutine::amparallelrescan, IndexAmRoutine::ampredlocks, IndexAmRoutine::amproperty, IndexAmRoutine::amrescan, IndexAmRoutine::amrestrpos, IndexAmRoutine::amsearcharray, IndexAmRoutine::amsearchnulls, IndexAmRoutine::amstorage, IndexAmRoutine::amstrategies, IndexAmRoutine::amsupport, IndexAmRoutine::amvacuumcleanup, IndexAmRoutine::amvalidate, btbeginscan(), btbuild(), btbuildempty(), btbulkdelete(), btcanreturn(), btcostestimate(), btendscan(), btestimateparallelscan(), btgetbitmap(), btgettuple(), btinitparallelscan(), btinsert(), btmarkpos(), BTMaxStrategyNumber, BTNProcs, btoptions(), btparallelrescan(), btproperty(), btrescan(), btrestrpos(), btvacuumcleanup(), btvalidate(), InvalidOid, makeNode, and PG_RETURN_POINTER.

{
    IndexAmRoutine *amroutine = makeNode(IndexAmRoutine);

    amroutine->amstrategies = BTMaxStrategyNumber;
    amroutine->amsupport = BTNProcs;
    amroutine->amcanorder = true;
    amroutine->amcanorderbyop = false;
    amroutine->amcanbackward = true;
    amroutine->amcanunique = true;
    amroutine->amcanmulticol = true;
    amroutine->amoptionalkey = true;
    amroutine->amsearcharray = true;
    amroutine->amsearchnulls = true;
    amroutine->amstorage = false;
    amroutine->amclusterable = true;
    amroutine->ampredlocks = true;
    amroutine->amcanparallel = true;
    amroutine->amkeytype = InvalidOid;

    amroutine->ambuild = btbuild;
    amroutine->ambuildempty = btbuildempty;
    amroutine->aminsert = btinsert;
    amroutine->ambulkdelete = btbulkdelete;
    amroutine->amvacuumcleanup = btvacuumcleanup;
    amroutine->amcanreturn = btcanreturn;
    amroutine->amcostestimate = btcostestimate;
    amroutine->amoptions = btoptions;
    amroutine->amproperty = btproperty;
    amroutine->amvalidate = btvalidate;
    amroutine->ambeginscan = btbeginscan;
    amroutine->amrescan = btrescan;
    amroutine->amgettuple = btgettuple;
    amroutine->amgetbitmap = btgetbitmap;
    amroutine->amendscan = btendscan;
    amroutine->ammarkpos = btmarkpos;
    amroutine->amrestrpos = btrestrpos;
    amroutine->amestimateparallelscan = btestimateparallelscan;
    amroutine->aminitparallelscan = btinitparallelscan;
    amroutine->amparallelrescan = btparallelrescan;

    PG_RETURN_POINTER(amroutine);
}

void btinitparallelscan

(

void *

target

)

Definition at line 710 of file nbtree.c.

References BTPARALLEL_NOT_INITIALIZED, BTParallelScanDescData::btps_arrayKeyCount, BTParallelScanDescData::btps_cv, BTParallelScanDescData::btps_mutex, BTParallelScanDescData::btps_pageStatus, BTParallelScanDescData::btps_scanPage, ConditionVariableInit(), InvalidBlockNumber, and SpinLockInit.

Referenced by bthandler().

{
    BTParallelScanDesc bt_target = (BTParallelScanDesc) target;

    SpinLockInit(&bt_target->btps_mutex);
    bt_target->btps_scanPage = InvalidBlockNumber;
    bt_target->btps_pageStatus = BTPARALLEL_NOT_INITIALIZED;
    bt_target->btps_arrayKeyCount = 0;
    ConditionVariableInit(&bt_target->btps_cv);
}

bool btinsert	(	Relation	rel,
		Datum *	values,
		bool *	isnull,
		ItemPointer	ht_ctid,
		Relation	heapRel,
		IndexUniqueCheck	checkUnique,
		IndexInfo *	indexInfo
	)

Definition at line 318 of file nbtree.c.

References _bt_doinsert(), index_form_tuple(), pfree(), RelationGetDescr, result, and IndexTupleData::t_tid.

Referenced by bthandler().

{
    bool        result;
    IndexTuple  itup;

    /* generate an index tuple */
    itup = index_form_tuple(RelationGetDescr(rel), values, isnull);
    itup->t_tid = *ht_ctid;

    result = _bt_doinsert(rel, itup, checkUnique, heapRel);

    pfree(itup);

    return result;
}

void btmarkpos

(

IndexScanDesc

scan

)

Definition at line 615 of file nbtree.c.

References BTScanPosInvalidate, BTScanPosIsValid, BTScanPosUnpinIfPinned, BTScanOpaqueData::currPos, BTScanPosData::itemIndex, BTScanOpaqueData::markItemIndex, BTScanOpaqueData::markPos, and IndexScanDescData::opaque.

Referenced by bthandler().

{
    BTScanOpaque so = (BTScanOpaque) scan->opaque;

    /* There may be an old mark with a pin (but no lock). */
    BTScanPosUnpinIfPinned(so->markPos);

    /*
     * Just record the current itemIndex.  If we later step to next page
     * before releasing the marked position, _bt_steppage makes a full copy of
     * the currPos struct in markPos.  If (as often happens) the mark is moved
     * before we leave the page, we don't have to do that work.
     */
    if (BTScanPosIsValid(so->currPos))
        so->markItemIndex = so->currPos.itemIndex;
    else
    {
        BTScanPosInvalidate(so->markPos);
        so->markItemIndex = -1;
    }

    /* Also record the current positions of any array keys */
    if (so->numArrayKeys)
        _bt_mark_array_keys(scan);
}

void btparallelrescan

(

IndexScanDesc

scan

)

Definition at line 725 of file nbtree.c.

References Assert, BTPARALLEL_NOT_INITIALIZED, BTParallelScanDescData::btps_arrayKeyCount, BTParallelScanDescData::btps_mutex, BTParallelScanDescData::btps_pageStatus, BTParallelScanDescData::btps_scanPage, InvalidBlockNumber, OffsetToPointer, IndexScanDescData::parallel_scan, ParallelIndexScanDescData::ps_offset, SpinLockAcquire, and SpinLockRelease.

Referenced by bthandler().

{
    BTParallelScanDesc btscan;
    ParallelIndexScanDesc parallel_scan = scan->parallel_scan;

    Assert(parallel_scan);

    btscan = (BTParallelScanDesc) OffsetToPointer((void *) parallel_scan,
                                                  parallel_scan->ps_offset);

    /*
     * In theory, we don't need to acquire the spinlock here, because there
     * shouldn't be any other workers running at this point, but we do so for
     * consistency.
     */
    SpinLockAcquire(&btscan->btps_mutex);
    btscan->btps_scanPage = InvalidBlockNumber;
    btscan->btps_pageStatus = BTPARALLEL_NOT_INITIALIZED;
    btscan->btps_arrayKeyCount = 0;
    SpinLockRelease(&btscan->btps_mutex);
}

void btrescan	(	IndexScanDesc	scan,
		ScanKey	scankey,
		int	nscankeys,
		ScanKey	orderbys,
		int	norderbys
	)

Definition at line 519 of file nbtree.c.

References _bt_killitems(), _bt_preprocess_array_keys(), BTScanOpaqueData::arrayKeyCount, BTScanPosInvalidate, BTScanPosIsValid, BTScanPosUnpinIfPinned, BTScanOpaqueData::currPos, BTScanOpaqueData::currTuples, IndexScanDescData::keyData, BTScanOpaqueData::markItemIndex, BTScanOpaqueData::markPos, BTScanOpaqueData::markTuples, memmove, NULL, IndexScanDescData::numberOfKeys, BTScanOpaqueData::numberOfKeys, BTScanOpaqueData::numKilled, IndexScanDescData::opaque, palloc(), and IndexScanDescData::xs_want_itup.

Referenced by bthandler().

{
    BTScanOpaque so = (BTScanOpaque) scan->opaque;

    /* we aren't holding any read locks, but gotta drop the pins */
    if (BTScanPosIsValid(so->currPos))
    {
        /* Before leaving current page, deal with any killed items */
        if (so->numKilled > 0)
            _bt_killitems(scan);
        BTScanPosUnpinIfPinned(so->currPos);
        BTScanPosInvalidate(so->currPos);
    }

    so->markItemIndex = -1;
    so->arrayKeyCount = 0;
    BTScanPosUnpinIfPinned(so->markPos);
    BTScanPosInvalidate(so->markPos);

    /*
     * Allocate tuple workspace arrays, if needed for an index-only scan and
     * not already done in a previous rescan call.  To save on palloc
     * overhead, both workspaces are allocated as one palloc block; only this
     * function and btendscan know that.
     *
     * NOTE: this data structure also makes it safe to return data from a
     * "name" column, even though btree name_ops uses an underlying storage
     * datatype of cstring.  The risk there is that "name" is supposed to be
     * padded to NAMEDATALEN, but the actual index tuple is probably shorter.
     * However, since we only return data out of tuples sitting in the
     * currTuples array, a fetch of NAMEDATALEN bytes can at worst pull some
     * data out of the markTuples array --- running off the end of memory for
     * a SIGSEGV is not possible.  Yeah, this is ugly as sin, but it beats
     * adding special-case treatment for name_ops elsewhere.
     */
    if (scan->xs_want_itup && so->currTuples == NULL)
    {
        so->currTuples = (char *) palloc(BLCKSZ * 2);
        so->markTuples = so->currTuples + BLCKSZ;
    }

    /*
     * Reset the scan keys. Note that keys ordering stuff moved to _bt_first.
     * - vadim 05/05/97
     */
    if (scankey && scan->numberOfKeys > 0)
        memmove(scan->keyData,
                scankey,
                scan->numberOfKeys * sizeof(ScanKeyData));
    so->numberOfKeys = 0;       /* until _bt_preprocess_keys sets it */

    /* If any keys are SK_SEARCHARRAY type, set up array-key info */
    _bt_preprocess_array_keys(scan);
}

void btrestrpos

(

IndexScanDesc

scan

)

Definition at line 645 of file nbtree.c.

References _bt_killitems(), _bt_restore_array_keys(), BTScanPosInvalidate, BTScanPosIsPinned, BTScanPosIsValid, BTScanPosUnpinIfPinned, BTScanPosData::buf, BTScanOpaqueData::currPos, BTScanOpaqueData::currTuples, IncrBufferRefCount(), BTScanPosData::itemIndex, BTScanPosData::lastItem, BTScanOpaqueData::markItemIndex, BTScanOpaqueData::markPos, BTScanOpaqueData::markTuples, BTScanPosData::nextTupleOffset, BTScanOpaqueData::numArrayKeys, BTScanOpaqueData::numKilled, offsetof, and IndexScanDescData::opaque.

Referenced by bthandler().

{
    BTScanOpaque so = (BTScanOpaque) scan->opaque;

    /* Restore the marked positions of any array keys */
    if (so->numArrayKeys)
        _bt_restore_array_keys(scan);

    if (so->markItemIndex >= 0)
    {
        /*
         * The scan has never moved to a new page since the last mark.  Just
         * restore the itemIndex.
         *
         * NB: In this case we can't count on anything in so->markPos to be
         * accurate.
         */
        so->currPos.itemIndex = so->markItemIndex;
    }
    else
    {
        /*
         * The scan moved to a new page after last mark or restore, and we are
         * now restoring to the marked page.  We aren't holding any read
         * locks, but if we're still holding the pin for the current position,
         * we must drop it.
         */
        if (BTScanPosIsValid(so->currPos))
        {
            /* Before leaving current page, deal with any killed items */
            if (so->numKilled > 0)
                _bt_killitems(scan);
            BTScanPosUnpinIfPinned(so->currPos);
        }

        if (BTScanPosIsValid(so->markPos))
        {
            /* bump pin on mark buffer for assignment to current buffer */
            if (BTScanPosIsPinned(so->markPos))
                IncrBufferRefCount(so->markPos.buf);
            memcpy(&so->currPos, &so->markPos,
                   offsetof(BTScanPosData, items[1]) +
                   so->markPos.lastItem * sizeof(BTScanPosItem));
            if (so->currTuples)
                memcpy(so->currTuples, so->markTuples,
                       so->markPos.nextTupleOffset);
        }
        else
            BTScanPosInvalidate(so->currPos);
    }
}

IndexBulkDeleteResult* btvacuumcleanup	(	IndexVacuumInfo *	info,
		IndexBulkDeleteResult *	stats
	)

Definition at line 946 of file nbtree.c.

References IndexVacuumInfo::analyze_only, btvacuumscan(), IndexVacuumInfo::estimated_count, IndexVacuumInfo::index, IndexFreeSpaceMapVacuum(), NULL, IndexVacuumInfo::num_heap_tuples, IndexBulkDeleteResult::num_index_tuples, and palloc0().

Referenced by bthandler().

{
    /* No-op in ANALYZE ONLY mode */
    if (info->analyze_only)
        return stats;

    /*
     * If btbulkdelete was called, we need not do anything, just return the
     * stats from the latest btbulkdelete call.  If it wasn't called, we must
     * still do a pass over the index, to recycle any newly-recyclable pages
     * and to obtain index statistics.
     *
     * Since we aren't going to actually delete any leaf items, there's no
     * need to go through all the vacuum-cycle-ID pushups.
     */
    if (stats == NULL)
    {
        stats = (IndexBulkDeleteResult *) palloc0(sizeof(IndexBulkDeleteResult));
        btvacuumscan(info, stats, NULL, NULL, 0);
    }

    /* Finally, vacuum the FSM */
    IndexFreeSpaceMapVacuum(info->index);

    /*
     * It's quite possible for us to be fooled by concurrent page splits into
     * double-counting some index tuples, so disbelieve any total that exceeds
     * the underlying heap's count ... if we know that accurately.  Otherwise
     * this might just make matters worse.
     */
    if (!info->estimated_count)
    {
        if (stats->num_index_tuples > info->num_heap_tuples)
            stats->num_index_tuples = info->num_heap_tuples;
    }

    return stats;
}

static void btvacuumpage ( BTVacState *  vstate, BlockNumber  blkno, BlockNumber  orig_blkno  )

static

Definition at line 1128 of file nbtree.c.

References _bt_checkpage(), _bt_delitems_vacuum(), _bt_page_recyclable(), _bt_pagedel(), _bt_relbuf(), BT_READ, BTP_SPLIT_END, BTPageOpaqueData::btpo_cycleid, BTPageOpaqueData::btpo_flags, BTPageOpaqueData::btpo_next, buf, BUFFER_LOCK_UNLOCK, BufferGetPage, callback(), BTVacState::callback, BTVacState::callback_state, BTVacState::cycleid, IndexVacuumInfo::index, BTVacState::info, BTVacState::lastBlockLocked, BTVacState::lastBlockVacuumed, LockBuffer(), LockBufferForCleanup(), MAIN_FORKNUM, MarkBufferDirtyHint(), MaxOffsetNumber, MemoryContextReset(), MemoryContextSwitchTo(), NULL, IndexBulkDeleteResult::num_index_tuples, OffsetNumberNext, P_FIRSTDATAKEY, P_IGNORE, P_ISDELETED, P_ISHALFDEAD, P_ISLEAF, P_NONE, P_RIGHTMOST, BTVacState::pagedelcontext, PageGetItem, PageGetItemId, PageGetMaxOffsetNumber, PageGetSpecialPointer, PageIsNew, IndexBulkDeleteResult::pages_deleted, RBM_NORMAL, ReadBufferExtended(), RecordFreeIndexPage(), BTVacState::stats, IndexVacuumInfo::strategy, IndexTupleData::t_tid, BTVacState::totFreePages, IndexBulkDeleteResult::tuples_removed, and vacuum_delay_point().

Referenced by btvacuumscan().

{
    IndexVacuumInfo *info = vstate->info;
    IndexBulkDeleteResult *stats = vstate->stats;
    IndexBulkDeleteCallback callback = vstate->callback;
    void       *callback_state = vstate->callback_state;
    Relation    rel = info->index;
    bool        delete_now;
    BlockNumber recurse_to;
    Buffer      buf;
    Page        page;
    BTPageOpaque opaque = NULL;

restart:
    delete_now = false;
    recurse_to = P_NONE;

    /* call vacuum_delay_point while not holding any buffer lock */
    vacuum_delay_point();

    /*
     * We can't use _bt_getbuf() here because it always applies
     * _bt_checkpage(), which will barf on an all-zero page. We want to
     * recycle all-zero pages, not fail.  Also, we want to use a nondefault
     * buffer access strategy.
     */
    buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_NORMAL,
                             info->strategy);
    LockBuffer(buf, BT_READ);
    page = BufferGetPage(buf);
    if (!PageIsNew(page))
    {
        _bt_checkpage(rel, buf);
        opaque = (BTPageOpaque) PageGetSpecialPointer(page);
    }

    /*
     * If we are recursing, the only case we want to do anything with is a
     * live leaf page having the current vacuum cycle ID.  Any other state
     * implies we already saw the page (eg, deleted it as being empty).
     */
    if (blkno != orig_blkno)
    {
        if (_bt_page_recyclable(page) ||
            P_IGNORE(opaque) ||
            !P_ISLEAF(opaque) ||
            opaque->btpo_cycleid != vstate->cycleid)
        {
            _bt_relbuf(rel, buf);
            return;
        }
    }

    /* Page is valid, see what to do with it */
    if (_bt_page_recyclable(page))
    {
        /* Okay to recycle this page */
        RecordFreeIndexPage(rel, blkno);
        vstate->totFreePages++;
        stats->pages_deleted++;
    }
    else if (P_ISDELETED(opaque))
    {
        /* Already deleted, but can't recycle yet */
        stats->pages_deleted++;
    }
    else if (P_ISHALFDEAD(opaque))
    {
        /* Half-dead, try to delete */
        delete_now = true;
    }
    else if (P_ISLEAF(opaque))
    {
        OffsetNumber deletable[MaxOffsetNumber];
        int         ndeletable;
        OffsetNumber offnum,
                    minoff,
                    maxoff;

        /*
         * Trade in the initial read lock for a super-exclusive write lock on
         * this page.  We must get such a lock on every leaf page over the
         * course of the vacuum scan, whether or not it actually contains any
         * deletable tuples --- see nbtree/README.
         */
        LockBuffer(buf, BUFFER_LOCK_UNLOCK);
        LockBufferForCleanup(buf);

        /*
         * Remember highest leaf page number we've taken cleanup lock on; see
         * notes in btvacuumscan
         */
        if (blkno > vstate->lastBlockLocked)
            vstate->lastBlockLocked = blkno;

        /*
         * Check whether we need to recurse back to earlier pages.  What we
         * are concerned about is a page split that happened since we started
         * the vacuum scan.  If the split moved some tuples to a lower page
         * then we might have missed 'em.  If so, set up for tail recursion.
         * (Must do this before possibly clearing btpo_cycleid below!)
         */
        if (vstate->cycleid != 0 &&
            opaque->btpo_cycleid == vstate->cycleid &&
            !(opaque->btpo_flags & BTP_SPLIT_END) &&
            !P_RIGHTMOST(opaque) &&
            opaque->btpo_next < orig_blkno)
            recurse_to = opaque->btpo_next;

        /*
         * Scan over all items to see which ones need deleted according to the
         * callback function.
         */
        ndeletable = 0;
        minoff = P_FIRSTDATAKEY(opaque);
        maxoff = PageGetMaxOffsetNumber(page);
        if (callback)
        {
            for (offnum = minoff;
                 offnum <= maxoff;
                 offnum = OffsetNumberNext(offnum))
            {
                IndexTuple  itup;
                ItemPointer htup;

                itup = (IndexTuple) PageGetItem(page,
                                                PageGetItemId(page, offnum));
                htup = &(itup->t_tid);

                /*
                 * During Hot Standby we currently assume that
                 * XLOG_BTREE_VACUUM records do not produce conflicts. That is
                 * only true as long as the callback function depends only
                 * upon whether the index tuple refers to heap tuples removed
                 * in the initial heap scan. When vacuum starts it derives a
                 * value of OldestXmin. Backends taking later snapshots could
                 * have a RecentGlobalXmin with a later xid than the vacuum's
                 * OldestXmin, so it is possible that row versions deleted
                 * after OldestXmin could be marked as killed by other
                 * backends. The callback function *could* look at the index
                 * tuple state in isolation and decide to delete the index
                 * tuple, though currently it does not. If it ever did, we
                 * would need to reconsider whether XLOG_BTREE_VACUUM records
                 * should cause conflicts. If they did cause conflicts they
                 * would be fairly harsh conflicts, since we haven't yet
                 * worked out a way to pass a useful value for
                 * latestRemovedXid on the XLOG_BTREE_VACUUM records. This
                 * applies to *any* type of index that marks index tuples as
                 * killed.
                 */
                if (callback(htup, callback_state))
                    deletable[ndeletable++] = offnum;
            }
        }

        /*
         * Apply any needed deletes.  We issue just one _bt_delitems_vacuum()
         * call per page, so as to minimize WAL traffic.
         */
        if (ndeletable > 0)
        {
            /*
             * Notice that the issued XLOG_BTREE_VACUUM WAL record includes
             * all information to the replay code to allow it to get a cleanup
             * lock on all pages between the previous lastBlockVacuumed and
             * this page. This ensures that WAL replay locks all leaf pages at
             * some point, which is important should non-MVCC scans be
             * requested. This is currently unused on standby, but we record
             * it anyway, so that the WAL contains the required information.
             *
             * Since we can visit leaf pages out-of-order when recursing,
             * replay might end up locking such pages an extra time, but it
             * doesn't seem worth the amount of bookkeeping it'd take to avoid
             * that.
             */
            _bt_delitems_vacuum(rel, buf, deletable, ndeletable,
                                vstate->lastBlockVacuumed);

            /*
             * Remember highest leaf page number we've issued a
             * XLOG_BTREE_VACUUM WAL record for.
             */
            if (blkno > vstate->lastBlockVacuumed)
                vstate->lastBlockVacuumed = blkno;

            stats->tuples_removed += ndeletable;
            /* must recompute maxoff */
            maxoff = PageGetMaxOffsetNumber(page);
        }
        else
        {
            /*
             * If the page has been split during this vacuum cycle, it seems
             * worth expending a write to clear btpo_cycleid even if we don't
             * have any deletions to do.  (If we do, _bt_delitems_vacuum takes
             * care of this.)  This ensures we won't process the page again.
             *
             * We treat this like a hint-bit update because there's no need to
             * WAL-log it.
             */
            if (vstate->cycleid != 0 &&
                opaque->btpo_cycleid == vstate->cycleid)
            {
                opaque->btpo_cycleid = 0;
                MarkBufferDirtyHint(buf, true);
            }
        }

        /*
         * If it's now empty, try to delete; else count the live tuples. We
         * don't delete when recursing, though, to avoid putting entries into
         * freePages out-of-order (doesn't seem worth any extra code to handle
         * the case).
         */
        if (minoff > maxoff)
            delete_now = (blkno == orig_blkno);
        else
            stats->num_index_tuples += maxoff - minoff + 1;
    }

    if (delete_now)
    {
        MemoryContext oldcontext;
        int         ndel;

        /* Run pagedel in a temp context to avoid memory leakage */
        MemoryContextReset(vstate->pagedelcontext);
        oldcontext = MemoryContextSwitchTo(vstate->pagedelcontext);

        ndel = _bt_pagedel(rel, buf);

        /* count only this page, else may double-count parent */
        if (ndel)
            stats->pages_deleted++;

        MemoryContextSwitchTo(oldcontext);
        /* pagedel released buffer, so we shouldn't */
    }
    else
        _bt_relbuf(rel, buf);

    /*
     * This is really tail recursion, but if the compiler is too stupid to
     * optimize it as such, we'd eat an uncomfortably large amount of stack
     * space per recursion level (due to the deletable[] array). A failure is
     * improbable since the number of levels isn't likely to be large ... but
     * just in case, let's hand-optimize into a loop.
     */
    if (recurse_to != P_NONE)
    {
        blkno = recurse_to;
        goto restart;
    }
}

static void btvacuumscan ( IndexVacuumInfo *  info, IndexBulkDeleteResult *  stats, IndexBulkDeleteCallback  callback, void *  callback_state, BTCycleId  cycleid  )

static

Definition at line 998 of file nbtree.c.

References _bt_checkpage(), _bt_delitems_vacuum(), _bt_relbuf(), ALLOCSET_DEFAULT_SIZES, AllocSetContextCreate(), BTREE_METAPAGE, btvacuumpage(), buf, callback(), BTVacState::callback, BTVacState::callback_state, CurrentMemoryContext, BTVacState::cycleid, IndexBulkDeleteResult::estimated_count, ExclusiveLock, IndexVacuumInfo::index, BTVacState::info, BTVacState::lastBlockLocked, BTVacState::lastBlockVacuumed, LockBufferForCleanup(), LockRelationForExtension(), MAIN_FORKNUM, MemoryContextDelete(), NULL, IndexBulkDeleteResult::num_index_tuples, IndexBulkDeleteResult::num_pages, BTVacState::pagedelcontext, IndexBulkDeleteResult::pages_deleted, IndexBulkDeleteResult::pages_free, RBM_NORMAL, ReadBufferExtended(), RELATION_IS_LOCAL, RelationGetNumberOfBlocks, BTVacState::stats, IndexVacuumInfo::strategy, BTVacState::totFreePages, UnlockRelationForExtension(), and XLogStandbyInfoActive.

Referenced by btbulkdelete(), and btvacuumcleanup().

{
    Relation    rel = info->index;
    BTVacState  vstate;
    BlockNumber num_pages;
    BlockNumber blkno;
    bool        needLock;

    /*
     * Reset counts that will be incremented during the scan; needed in case
     * of multiple scans during a single VACUUM command
     */
    stats->estimated_count = false;
    stats->num_index_tuples = 0;
    stats->pages_deleted = 0;

    /* Set up info to pass down to btvacuumpage */
    vstate.info = info;
    vstate.stats = stats;
    vstate.callback = callback;
    vstate.callback_state = callback_state;
    vstate.cycleid = cycleid;
    vstate.lastBlockVacuumed = BTREE_METAPAGE;  /* Initialise at first block */
    vstate.lastBlockLocked = BTREE_METAPAGE;
    vstate.totFreePages = 0;

    /* Create a temporary memory context to run _bt_pagedel in */
    vstate.pagedelcontext = AllocSetContextCreate(CurrentMemoryContext,
                                                  "_bt_pagedel",
                                                  ALLOCSET_DEFAULT_SIZES);

    /*
     * The outer loop iterates over all index pages except the metapage, in
     * physical order (we hope the kernel will cooperate in providing
     * read-ahead for speed).  It is critical that we visit all leaf pages,
     * including ones added after we start the scan, else we might fail to
     * delete some deletable tuples.  Hence, we must repeatedly check the
     * relation length.  We must acquire the relation-extension lock while
     * doing so to avoid a race condition: if someone else is extending the
     * relation, there is a window where bufmgr/smgr have created a new
     * all-zero page but it hasn't yet been write-locked by _bt_getbuf(). If
     * we manage to scan such a page here, we'll improperly assume it can be
     * recycled.  Taking the lock synchronizes things enough to prevent a
     * problem: either num_pages won't include the new page, or _bt_getbuf
     * already has write lock on the buffer and it will be fully initialized
     * before we can examine it.  (See also vacuumlazy.c, which has the same
     * issue.)  Also, we need not worry if a page is added immediately after
     * we look; the page splitting code already has write-lock on the left
     * page before it adds a right page, so we must already have processed any
     * tuples due to be moved into such a page.
     *
     * We can skip locking for new or temp relations, however, since no one
     * else could be accessing them.
     */
    needLock = !RELATION_IS_LOCAL(rel);

    blkno = BTREE_METAPAGE + 1;
    for (;;)
    {
        /* Get the current relation length */
        if (needLock)
            LockRelationForExtension(rel, ExclusiveLock);
        num_pages = RelationGetNumberOfBlocks(rel);
        if (needLock)
            UnlockRelationForExtension(rel, ExclusiveLock);

        /* Quit if we've scanned the whole relation */
        if (blkno >= num_pages)
            break;
        /* Iterate over pages, then loop back to recheck length */
        for (; blkno < num_pages; blkno++)
        {
            btvacuumpage(&vstate, blkno, blkno);
        }
    }

    /*
     * Check to see if we need to issue one final WAL record for this index,
     * which may be needed for correctness on a hot standby node when non-MVCC
     * index scans could take place.
     *
     * If the WAL is replayed in hot standby, the replay process needs to get
     * cleanup locks on all index leaf pages, just as we've been doing here.
     * However, we won't issue any WAL records about pages that have no items
     * to be deleted.  For pages between pages we've vacuumed, the replay code
     * will take locks under the direction of the lastBlockVacuumed fields in
     * the XLOG_BTREE_VACUUM WAL records.  To cover pages after the last one
     * we vacuum, we need to issue a dummy XLOG_BTREE_VACUUM WAL record
     * against the last leaf page in the index, if that one wasn't vacuumed.
     */
    if (XLogStandbyInfoActive() &&
        vstate.lastBlockVacuumed < vstate.lastBlockLocked)
    {
        Buffer      buf;

        /*
         * The page should be valid, but we can't use _bt_getbuf() because we
         * want to use a nondefault buffer access strategy.  Since we aren't
         * going to delete any items, getting cleanup lock again is probably
         * overkill, but for consistency do that anyway.
         */
        buf = ReadBufferExtended(rel, MAIN_FORKNUM, vstate.lastBlockLocked,
                                 RBM_NORMAL, info->strategy);
        LockBufferForCleanup(buf);
        _bt_checkpage(rel, buf);
        _bt_delitems_vacuum(rel, buf, NULL, 0, vstate.lastBlockVacuumed);
        _bt_relbuf(rel, buf);
    }

    MemoryContextDelete(vstate.pagedelcontext);

    /* update statistics */
    stats->num_pages = num_pages;
    stats->pages_free = vstate.totFreePages;
}