hash.c File Reference

#include "postgres.h"
#include "access/hash.h"
#include "access/hash_xlog.h"
#include "access/relscan.h"
#include "access/stratnum.h"
#include "access/tableam.h"
#include "access/xloginsert.h"
#include "commands/progress.h"
#include "commands/vacuum.h"
#include "miscadmin.h"
#include "nodes/execnodes.h"
#include "optimizer/plancat.h"
#include "pgstat.h"
#include "storage/read_stream.h"
#include "utils/fmgrprotos.h"
#include "utils/index_selfuncs.h"
#include "utils/rel.h"

Include dependency graph for hash.c:

Go to the source code of this file.

Data Structures
struct	HashBuildState
struct	HashBulkDeleteStreamPrivate

Functions
static void	hashbuildCallback (Relation index, ItemPointer tid, Datum *values, bool *isnull, bool tupleIsAlive, void *state)
static BlockNumber	hash_bulkdelete_read_stream_cb (ReadStream *stream, void *callback_private_data, void *per_buffer_data)
Datum	hashhandler (PG_FUNCTION_ARGS)
IndexBuildResult *	hashbuild (Relation heap, Relation index, IndexInfo *indexInfo)
void	hashbuildempty (Relation index)
bool	hashinsert (Relation rel, Datum *values, bool *isnull, ItemPointer ht_ctid, Relation heapRel, IndexUniqueCheck checkUnique, bool indexUnchanged, IndexInfo *indexInfo)
bool	hashgettuple (IndexScanDesc scan, ScanDirection dir)
int64	hashgetbitmap (IndexScanDesc scan, TIDBitmap *tbm)
IndexScanDesc	hashbeginscan (Relation rel, int nkeys, int norderbys)
void	hashrescan (IndexScanDesc scan, ScanKey scankey, int nscankeys, ScanKey orderbys, int norderbys)
void	hashendscan (IndexScanDesc scan)
IndexBulkDeleteResult *	hashbulkdelete (IndexVacuumInfo *info, IndexBulkDeleteResult *stats, IndexBulkDeleteCallback callback, void *callback_state)
IndexBulkDeleteResult *	hashvacuumcleanup (IndexVacuumInfo *info, IndexBulkDeleteResult *stats)
void	hashbucketcleanup (Relation rel, Bucket cur_bucket, Buffer bucket_buf, BlockNumber bucket_blkno, BufferAccessStrategy bstrategy, uint32 maxbucket, uint32 highmask, uint32 lowmask, double *tuples_removed, double *num_index_tuples, bool split_cleanup, IndexBulkDeleteCallback callback, void *callback_state)
CompareType	hashtranslatestrategy (StrategyNumber strategy, Oid opfamily)
StrategyNumber	hashtranslatecmptype (CompareType cmptype, Oid opfamily)

Function Documentation

hash_bulkdelete_read_stream_cb()

static BlockNumber hash_bulkdelete_read_stream_cb ( ReadStream *  stream, void *  callback_private_data, void *  per_buffer_data  )

static

Definition at line 473 of file hash.c.

{
    HashBulkDeleteStreamPrivate *p = callback_private_data;
    Bucket      bucket;
 
    if (p->next_bucket > p->max_bucket)
        return InvalidBlockNumber;
 
    bucket = p->next_bucket++;
    return BUCKET_TO_BLKNO(p->metap, bucket);
}

References BUCKET_TO_BLKNO, fb(), InvalidBlockNumber, HashBulkDeleteStreamPrivate::max_bucket, HashBulkDeleteStreamPrivate::metap, and HashBulkDeleteStreamPrivate::next_bucket.

Referenced by hashbulkdelete().

hashbeginscan()

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

Definition at line 386 of file hash.c.

{
    IndexScanDesc scan;
    HashScanOpaque so;
 
    /* no order by operators allowed */
    Assert(norderbys == 0);
 
    scan = RelationGetIndexScan(rel, nkeys, norderbys);
 
    so = (HashScanOpaque) palloc_object(HashScanOpaqueData);
    HashScanPosInvalidate(so->currPos);
    so->hashso_bucket_buf = InvalidBuffer;
    so->hashso_split_bucket_buf = InvalidBuffer;
 
    so->hashso_buc_populated = false;
    so->hashso_buc_split = false;
 
    so->killedItems = NULL;
    so->numKilled = 0;
 
    scan->opaque = so;
 
    return scan;
}

References Assert, fb(), HashScanPosInvalidate, InvalidBuffer, IndexScanDescData::opaque, palloc_object, and RelationGetIndexScan().

Referenced by hashhandler().

hashbucketcleanup()

void hashbucketcleanup	(	Relation	rel,
		Bucket	cur_bucket,
		Buffer	bucket_buf,
		BlockNumber	bucket_blkno,
		BufferAccessStrategy	bstrategy,
		uint32	maxbucket,
		uint32	highmask,
		uint32	lowmask,
		double *	tuples_removed,
		double *	num_index_tuples,
		bool	split_cleanup,
		IndexBulkDeleteCallback	callback,
		void *	callback_state
	)

Definition at line 767 of file hash.c.

{
    BlockNumber blkno;
    Buffer      buf;
    Bucket      new_bucket PG_USED_FOR_ASSERTS_ONLY = InvalidBucket;
    bool        bucket_dirty = false;
    XLogRecPtr  recptr;
 
    blkno = bucket_blkno;
    buf = bucket_buf;
 
    if (split_cleanup)
        new_bucket = _hash_get_newbucket_from_oldbucket(rel, cur_bucket,
                                                        lowmask, maxbucket);
 
    /* Scan each page in bucket */
    for (;;)
    {
        HashPageOpaque opaque;
        OffsetNumber offno;
        OffsetNumber maxoffno;
        Buffer      next_buf;
        Page        page;
        OffsetNumber deletable[MaxOffsetNumber];
        int         ndeletable = 0;
        bool        retain_pin = false;
        bool        clear_dead_marking = false;
 
        vacuum_delay_point(false);
 
        page = BufferGetPage(buf);
        opaque = HashPageGetOpaque(page);
 
        /* Scan each tuple in page */
        maxoffno = PageGetMaxOffsetNumber(page);
        for (offno = FirstOffsetNumber;
             offno <= maxoffno;
             offno = OffsetNumberNext(offno))
        {
            ItemPointer htup;
            IndexTuple  itup;
            Bucket      bucket;
            bool        kill_tuple = false;
 
            itup = (IndexTuple) PageGetItem(page,
                                            PageGetItemId(page, offno));
            htup = &(itup->t_tid);
 
            /*
             * To remove the dead tuples, we strictly want to rely on results
             * of callback function.  refer btvacuumpage for detailed reason.
             */
            if (callback && callback(htup, callback_state))
            {
                kill_tuple = true;
                if (tuples_removed)
                    *tuples_removed += 1;
            }
            else if (split_cleanup)
            {
                /* delete the tuples that are moved by split. */
                bucket = _hash_hashkey2bucket(_hash_get_indextuple_hashkey(itup),
                                              maxbucket,
                                              highmask,
                                              lowmask);
                /* mark the item for deletion */
                if (bucket != cur_bucket)
                {
                    /*
                     * We expect tuples to either belong to current bucket or
                     * new_bucket.  This is ensured because we don't allow
                     * further splits from bucket that contains garbage. See
                     * comments in _hash_expandtable.
                     */
                    Assert(bucket == new_bucket);
                    kill_tuple = true;
                }
            }
 
            if (kill_tuple)
            {
                /* mark the item for deletion */
                deletable[ndeletable++] = offno;
            }
            else
            {
                /* we're keeping it, so count it */
                if (num_index_tuples)
                    *num_index_tuples += 1;
            }
        }
 
        /* retain the pin on primary bucket page till end of bucket scan */
        if (blkno == bucket_blkno)
            retain_pin = true;
        else
            retain_pin = false;
 
        blkno = opaque->hasho_nextblkno;
 
        /*
         * Apply deletions, advance to next page and write page if needed.
         */
        if (ndeletable > 0)
        {
            /* No ereport(ERROR) until changes are logged */
            START_CRIT_SECTION();
 
            PageIndexMultiDelete(page, deletable, ndeletable);
            bucket_dirty = true;
 
            /*
             * Let us mark the page as clean if vacuum removes the DEAD tuples
             * from an index page. We do this by clearing
             * LH_PAGE_HAS_DEAD_TUPLES flag.
             */
            if (tuples_removed && *tuples_removed > 0 &&
                H_HAS_DEAD_TUPLES(opaque))
            {
                opaque->hasho_flag &= ~LH_PAGE_HAS_DEAD_TUPLES;
                clear_dead_marking = true;
            }
 
            MarkBufferDirty(buf);
 
            /* XLOG stuff */
            if (RelationNeedsWAL(rel))
            {
                xl_hash_delete xlrec;
 
                xlrec.clear_dead_marking = clear_dead_marking;
                xlrec.is_primary_bucket_page = (buf == bucket_buf);
 
                XLogBeginInsert();
                XLogRegisterData(&xlrec, SizeOfHashDelete);
 
                /*
                 * bucket buffer was not changed, but still needs to be
                 * registered to ensure that we can acquire a cleanup lock on
                 * it during replay.
                 */
                if (!xlrec.is_primary_bucket_page)
                {
                    uint8       flags = REGBUF_STANDARD | REGBUF_NO_IMAGE | REGBUF_NO_CHANGE;
 
                    XLogRegisterBuffer(0, bucket_buf, flags);
                }
 
                XLogRegisterBuffer(1, buf, REGBUF_STANDARD);
                XLogRegisterBufData(1, deletable,
                                    ndeletable * sizeof(OffsetNumber));
 
                recptr = XLogInsert(RM_HASH_ID, XLOG_HASH_DELETE);
            }
            else
                recptr = XLogGetFakeLSN(rel);
 
            PageSetLSN(BufferGetPage(buf), recptr);
 
            END_CRIT_SECTION();
        }
 
        /* bail out if there are no more pages to scan. */
        if (!BlockNumberIsValid(blkno))
            break;
 
        next_buf = _hash_getbuf_with_strategy(rel, blkno, HASH_WRITE,
                                              LH_OVERFLOW_PAGE,
                                              bstrategy);
 
        /*
         * release the lock on previous page after acquiring the lock on next
         * page
         */
        if (retain_pin)
            LockBuffer(buf, BUFFER_LOCK_UNLOCK);
        else
            _hash_relbuf(rel, buf);
 
        buf = next_buf;
    }
 
    /*
     * lock the bucket page to clear the garbage flag and squeeze the bucket.
     * if the current buffer is same as bucket buffer, then we already have
     * lock on bucket page.
     */
    if (buf != bucket_buf)
    {
        _hash_relbuf(rel, buf);
        LockBuffer(bucket_buf, BUFFER_LOCK_EXCLUSIVE);
    }
 
    /*
     * Clear the garbage flag from bucket after deleting the tuples that are
     * moved by split.  We purposefully clear the flag before squeeze bucket,
     * so that after restart, vacuum shouldn't again try to delete the moved
     * by split tuples.
     */
    if (split_cleanup)
    {
        HashPageOpaque bucket_opaque;
        Page        page;
 
        page = BufferGetPage(bucket_buf);
        bucket_opaque = HashPageGetOpaque(page);
 
        /* No ereport(ERROR) until changes are logged */
        START_CRIT_SECTION();
 
        bucket_opaque->hasho_flag &= ~LH_BUCKET_NEEDS_SPLIT_CLEANUP;
        MarkBufferDirty(bucket_buf);
 
        /* XLOG stuff */
        if (RelationNeedsWAL(rel))
        {
            XLogBeginInsert();
            XLogRegisterBuffer(0, bucket_buf, REGBUF_STANDARD);
 
            recptr = XLogInsert(RM_HASH_ID, XLOG_HASH_SPLIT_CLEANUP);
        }
        else
            recptr = XLogGetFakeLSN(rel);
 
        PageSetLSN(page, recptr);
 
        END_CRIT_SECTION();
    }
 
    /*
     * If we have deleted anything, try to compact free space.  For squeezing
     * the bucket, we must have a cleanup lock, else it can impact the
     * ordering of tuples for a scan that has started before it.
     */
    if (bucket_dirty && IsBufferCleanupOK(bucket_buf))
        _hash_squeezebucket(rel, cur_bucket, bucket_blkno, bucket_buf,
                            bstrategy);
    else
        LockBuffer(bucket_buf, BUFFER_LOCK_UNLOCK);
}

References _hash_get_indextuple_hashkey(), _hash_get_newbucket_from_oldbucket(), _hash_getbuf_with_strategy(), _hash_hashkey2bucket(), _hash_relbuf(), _hash_squeezebucket(), Assert, BlockNumberIsValid(), buf, BUFFER_LOCK_EXCLUSIVE, BUFFER_LOCK_UNLOCK, BufferGetPage(), callback(), xl_hash_delete::clear_dead_marking, END_CRIT_SECTION, fb(), FirstOffsetNumber, H_HAS_DEAD_TUPLES, HASH_WRITE, HashPageOpaqueData::hasho_flag, HashPageOpaqueData::hasho_nextblkno, HashPageGetOpaque, InvalidBucket, IsBufferCleanupOK(), LH_OVERFLOW_PAGE, LockBuffer(), MarkBufferDirty(), MaxOffsetNumber, OffsetNumberNext, PageGetItem(), PageGetItemId(), PageGetMaxOffsetNumber(), PageIndexMultiDelete(), PageSetLSN(), PG_USED_FOR_ASSERTS_ONLY, REGBUF_NO_CHANGE, REGBUF_NO_IMAGE, REGBUF_STANDARD, RelationNeedsWAL, SizeOfHashDelete, START_CRIT_SECTION, IndexTupleData::t_tid, vacuum_delay_point(), XLOG_HASH_DELETE, XLOG_HASH_SPLIT_CLEANUP, XLogBeginInsert(), XLogGetFakeLSN(), XLogInsert(), XLogRegisterBufData(), XLogRegisterBuffer(), and XLogRegisterData().

Referenced by _hash_expandtable(), _hash_splitbucket(), and hashbulkdelete().

hashbuild()

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

Definition at line 135 of file hash.c.

{
    IndexBuildResult *result;
    BlockNumber relpages;
    double      reltuples;
    double      allvisfrac;
    uint32      num_buckets;
    Size        sort_threshold;
    HashBuildState buildstate;
 
    /*
     * 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));
 
    /* Estimate the number of rows currently present in the table */
    estimate_rel_size(heap, NULL, &relpages, &reltuples, &allvisfrac);
 
    /* Initialize the hash index metadata page and initial buckets */
    num_buckets = _hash_init(index, reltuples, MAIN_FORKNUM);
 
    /*
     * If we just insert the tuples into the index in scan order, then
     * (assuming their hash codes are pretty random) there will be no locality
     * of access to the index, and if the index is bigger than available RAM
     * then we'll thrash horribly.  To prevent that scenario, we can sort the
     * tuples by (expected) bucket number.  However, such a sort is useless
     * overhead when the index does fit in RAM.  We choose to sort if the
     * initial index size exceeds maintenance_work_mem, or the number of
     * buffers usable for the index, whichever is less.  (Limiting by the
     * number of buffers should reduce thrashing between PG buffers and kernel
     * buffers, which seems useful even if no physical I/O results.  Limiting
     * by maintenance_work_mem is useful to allow easy testing of the sort
     * code path, and may be useful to DBAs as an additional control knob.)
     *
     * NOTE: this test will need adjustment if a bucket is ever different from
     * one page.  Also, "initial index size" accounting does not include the
     * metapage, nor the first bitmap page.
     */
    sort_threshold = (maintenance_work_mem * (Size) 1024) / BLCKSZ;
    if (index->rd_rel->relpersistence != RELPERSISTENCE_TEMP)
        sort_threshold = Min(sort_threshold, NBuffers);
    else
        sort_threshold = Min(sort_threshold, NLocBuffer);
 
    if (num_buckets >= sort_threshold)
        buildstate.spool = _h_spoolinit(heap, index, num_buckets);
    else
        buildstate.spool = NULL;
 
    /* prepare to build the index */
    buildstate.indtuples = 0;
    buildstate.heapRel = heap;
 
    /* do the heap scan */
    reltuples = table_index_build_scan(heap, index, indexInfo, true, true,
                                       hashbuildCallback,
                                       &buildstate, NULL);
    pgstat_progress_update_param(PROGRESS_CREATEIDX_TUPLES_TOTAL,
                                 buildstate.indtuples);
 
    if (buildstate.spool)
    {
        /* sort the tuples and insert them into the index */
        _h_indexbuild(buildstate.spool, buildstate.heapRel);
        _h_spooldestroy(buildstate.spool);
    }
 
    /*
     * Return statistics
     */
    result = palloc_object(IndexBuildResult);
 
    result->heap_tuples = reltuples;
    result->index_tuples = buildstate.indtuples;
 
    return result;
}

References _h_indexbuild(), _h_spooldestroy(), _h_spoolinit(), _hash_init(), elog, ERROR, estimate_rel_size(), fb(), hashbuildCallback(), IndexBuildResult::heap_tuples, IndexBuildResult::index_tuples, MAIN_FORKNUM, maintenance_work_mem, Min, NBuffers, NLocBuffer, palloc_object, pgstat_progress_update_param(), PROGRESS_CREATEIDX_TUPLES_TOTAL, RelationGetNumberOfBlocks, RelationGetRelationName, and table_index_build_scan().

Referenced by hashhandler().

hashbuildCallback()

static void hashbuildCallback ( Relation  index, ItemPointer  tid, Datum *  values, bool *  isnull, bool  tupleIsAlive, void *  state  )

static

Definition at line 230 of file hash.c.

{
    HashBuildState *buildstate = (HashBuildState *) state;
    Datum       index_values[1];
    bool        index_isnull[1];
    IndexTuple  itup;
 
    /* convert data to a hash key; on failure, do not insert anything */
    if (!_hash_convert_tuple(index,
                             values, isnull,
                             index_values, index_isnull))
        return;
 
    /* Either spool the tuple for sorting, or just put it into the index */
    if (buildstate->spool)
        _h_spool(buildstate->spool, tid, index_values, index_isnull);
    else
    {
        /* form an index tuple and point it at the heap tuple */
        itup = index_form_tuple(RelationGetDescr(index),
                                index_values, index_isnull);
        itup->t_tid = *tid;
        _hash_doinsert(index, itup, buildstate->heapRel, false);
        pfree(itup);
    }
 
    buildstate->indtuples += 1;
}

References _h_spool(), _hash_convert_tuple(), _hash_doinsert(), fb(), index_form_tuple(), pfree(), RelationGetDescr, IndexTupleData::t_tid, and values.

Referenced by hashbuild().

hashbuildempty()

void hashbuildempty

(

Relation

index

)

Definition at line 221 of file hash.c.

{
    _hash_init(index, 0, INIT_FORKNUM);
}

References _hash_init(), and INIT_FORKNUM.

Referenced by hashhandler().

hashbulkdelete()

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

Definition at line 498 of file hash.c.

{
    Relation    rel = info->index;
    double      tuples_removed;
    double      num_index_tuples;
    double      orig_ntuples;
    Bucket      orig_maxbucket;
    Bucket      cur_maxbucket;
    Bucket      cur_bucket;
    Buffer      metabuf = InvalidBuffer;
    HashMetaPage metap;
    HashMetaPage cachedmetap;
    HashBulkDeleteStreamPrivate stream_private;
    ReadStream *stream = NULL;
    XLogRecPtr  recptr;
 
    tuples_removed = 0;
    num_index_tuples = 0;
 
    /*
     * We need a copy of the metapage so that we can use its hashm_spares[]
     * values to compute bucket page addresses, but a cached copy should be
     * good enough.  (If not, we'll detect that further down and refresh the
     * cache as necessary.)
     */
    cachedmetap = _hash_getcachedmetap(rel, &metabuf, false);
    Assert(cachedmetap != NULL);
 
    orig_maxbucket = cachedmetap->hashm_maxbucket;
    orig_ntuples = cachedmetap->hashm_ntuples;
 
    /* Scan the buckets that we know exist */
    cur_bucket = 0;
    cur_maxbucket = orig_maxbucket;
 
    /* Set up streaming read for primary bucket pages */
    stream_private.metap = cachedmetap;
    stream_private.next_bucket = cur_bucket;
    stream_private.max_bucket = cur_maxbucket;
 
    /*
     * It is safe to use batchmode as hash_bulkdelete_read_stream_cb takes no
     * locks.
     */
    stream = read_stream_begin_relation(READ_STREAM_MAINTENANCE |
                                        READ_STREAM_USE_BATCHING,
                                        info->strategy,
                                        rel,
                                        MAIN_FORKNUM,
                                        hash_bulkdelete_read_stream_cb,
                                        &stream_private,
                                        0);
 
bucket_loop:
    while (cur_bucket <= cur_maxbucket)
    {
        BlockNumber bucket_blkno;
        BlockNumber blkno;
        Buffer      bucket_buf;
        Buffer      buf;
        HashPageOpaque bucket_opaque;
        Page        page;
        bool        split_cleanup = false;
 
        /* Get address of bucket's start page */
        bucket_blkno = BUCKET_TO_BLKNO(cachedmetap, cur_bucket);
 
        blkno = bucket_blkno;
 
        /*
         * We need to acquire a cleanup lock on the primary bucket page to out
         * wait concurrent scans before deleting the dead tuples.
         */
        buf = read_stream_next_buffer(stream, NULL);
        Assert(BufferIsValid(buf));
        LockBufferForCleanup(buf);
        _hash_checkpage(rel, buf, LH_BUCKET_PAGE);
 
        page = BufferGetPage(buf);
        bucket_opaque = HashPageGetOpaque(page);
 
        /*
         * If the bucket contains tuples that are moved by split, then we need
         * to delete such tuples.  We can't delete such tuples if the split
         * operation on bucket is not finished as those are needed by scans.
         */
        if (!H_BUCKET_BEING_SPLIT(bucket_opaque) &&
            H_NEEDS_SPLIT_CLEANUP(bucket_opaque))
        {
            split_cleanup = true;
 
            /*
             * This bucket might have been split since we last held a lock on
             * the metapage.  If so, hashm_maxbucket, hashm_highmask and
             * hashm_lowmask might be old enough to cause us to fail to remove
             * tuples left behind by the most recent split.  To prevent that,
             * now that the primary page of the target bucket has been locked
             * (and thus can't be further split), check whether we need to
             * update our cached metapage data.
             */
            Assert(bucket_opaque->hasho_prevblkno != InvalidBlockNumber);
            if (bucket_opaque->hasho_prevblkno > cachedmetap->hashm_maxbucket)
            {
                cachedmetap = _hash_getcachedmetap(rel, &metabuf, true);
                Assert(cachedmetap != NULL);
 
                /*
                 * Reset stream with updated metadata for remaining buckets.
                 * The BUCKET_TO_BLKNO mapping depends on hashm_spares[],
                 * which may have changed.
                 */
                stream_private.metap = cachedmetap;
                stream_private.next_bucket = cur_bucket + 1;
                stream_private.max_bucket = cur_maxbucket;
                read_stream_reset(stream);
            }
        }
 
        bucket_buf = buf;
 
        hashbucketcleanup(rel, cur_bucket, bucket_buf, blkno, info->strategy,
                          cachedmetap->hashm_maxbucket,
                          cachedmetap->hashm_highmask,
                          cachedmetap->hashm_lowmask, &tuples_removed,
                          &num_index_tuples, split_cleanup,
                          callback, callback_state);
 
        _hash_dropbuf(rel, bucket_buf);
 
        /* Advance to next bucket */
        cur_bucket++;
    }
 
    if (BufferIsInvalid(metabuf))
        metabuf = _hash_getbuf(rel, HASH_METAPAGE, HASH_NOLOCK, LH_META_PAGE);
 
    /* Write-lock metapage and check for split since we started */
    LockBuffer(metabuf, BUFFER_LOCK_EXCLUSIVE);
    metap = HashPageGetMeta(BufferGetPage(metabuf));
 
    if (cur_maxbucket != metap->hashm_maxbucket)
    {
        /* There's been a split, so process the additional bucket(s) */
        LockBuffer(metabuf, BUFFER_LOCK_UNLOCK);
        cachedmetap = _hash_getcachedmetap(rel, &metabuf, true);
        Assert(cachedmetap != NULL);
        cur_maxbucket = cachedmetap->hashm_maxbucket;
 
        /* Reset stream to process additional buckets from split */
        stream_private.metap = cachedmetap;
        stream_private.next_bucket = cur_bucket;
        stream_private.max_bucket = cur_maxbucket;
        read_stream_reset(stream);
        goto bucket_loop;
    }
 
    /* Stream should be exhausted since we processed all buckets */
    Assert(read_stream_next_buffer(stream, NULL) == InvalidBuffer);
    read_stream_end(stream);
 
    /* Okay, we're really done.  Update tuple count in metapage. */
    START_CRIT_SECTION();
 
    if (orig_maxbucket == metap->hashm_maxbucket &&
        orig_ntuples == metap->hashm_ntuples)
    {
        /*
         * No one has split or inserted anything since start of scan, so
         * believe our count as gospel.
         */
        metap->hashm_ntuples = num_index_tuples;
    }
    else
    {
        /*
         * Otherwise, our count is untrustworthy since we may have
         * double-scanned tuples in split buckets.  Proceed by dead-reckoning.
         * (Note: we still return estimated_count = false, because using this
         * count is better than not updating reltuples at all.)
         */
        if (metap->hashm_ntuples > tuples_removed)
            metap->hashm_ntuples -= tuples_removed;
        else
            metap->hashm_ntuples = 0;
        num_index_tuples = metap->hashm_ntuples;
    }
 
    MarkBufferDirty(metabuf);
 
    /* XLOG stuff */
    if (RelationNeedsWAL(rel))
    {
        xl_hash_update_meta_page xlrec;
 
        xlrec.ntuples = metap->hashm_ntuples;
 
        XLogBeginInsert();
        XLogRegisterData(&xlrec, SizeOfHashUpdateMetaPage);
 
        XLogRegisterBuffer(0, metabuf, REGBUF_STANDARD);
 
        recptr = XLogInsert(RM_HASH_ID, XLOG_HASH_UPDATE_META_PAGE);
    }
    else
        recptr = XLogGetFakeLSN(rel);
 
    PageSetLSN(BufferGetPage(metabuf), recptr);
 
    END_CRIT_SECTION();
 
    _hash_relbuf(rel, metabuf);
 
    /* return statistics */
    if (stats == NULL)
        stats = palloc0_object(IndexBulkDeleteResult);
    stats->estimated_count = false;
    stats->num_index_tuples = num_index_tuples;
    stats->tuples_removed += tuples_removed;
    /* hashvacuumcleanup will fill in num_pages */
 
    return stats;
}

References _hash_checkpage(), _hash_dropbuf(), _hash_getbuf(), _hash_getcachedmetap(), _hash_relbuf(), Assert, BUCKET_TO_BLKNO, buf, BUFFER_LOCK_EXCLUSIVE, BUFFER_LOCK_UNLOCK, BufferGetPage(), BufferIsInvalid, BufferIsValid(), callback(), END_CRIT_SECTION, IndexBulkDeleteResult::estimated_count, fb(), H_BUCKET_BEING_SPLIT, H_NEEDS_SPLIT_CLEANUP, hash_bulkdelete_read_stream_cb(), HASH_METAPAGE, HASH_NOLOCK, hashbucketcleanup(), HashMetaPageData::hashm_maxbucket, HashMetaPageData::hashm_ntuples, HashPageGetMeta, HashPageGetOpaque, IndexVacuumInfo::index, InvalidBlockNumber, InvalidBuffer, LH_BUCKET_PAGE, LH_META_PAGE, LockBuffer(), LockBufferForCleanup(), MAIN_FORKNUM, MarkBufferDirty(), xl_hash_update_meta_page::ntuples, IndexBulkDeleteResult::num_index_tuples, PageSetLSN(), palloc0_object, read_stream_begin_relation(), read_stream_end(), READ_STREAM_MAINTENANCE, read_stream_next_buffer(), read_stream_reset(), READ_STREAM_USE_BATCHING, REGBUF_STANDARD, RelationNeedsWAL, SizeOfHashUpdateMetaPage, START_CRIT_SECTION, IndexVacuumInfo::strategy, IndexBulkDeleteResult::tuples_removed, XLOG_HASH_UPDATE_META_PAGE, XLogBeginInsert(), XLogGetFakeLSN(), XLogInsert(), XLogRegisterBuffer(), and XLogRegisterData().

Referenced by hashhandler().

hashendscan()

void hashendscan

(

IndexScanDesc

scan

)

Definition at line 446 of file hash.c.

{
    HashScanOpaque so = (HashScanOpaque) scan->opaque;
    Relation    rel = scan->indexRelation;
 
    if (HashScanPosIsValid(so->currPos))
    {
        /* Before leaving current page, deal with any killed items */
        if (so->numKilled > 0)
            _hash_kill_items(scan);
    }
 
    _hash_dropscanbuf(rel, so);
 
    if (so->killedItems != NULL)
        pfree(so->killedItems);
    pfree(so);
    scan->opaque = NULL;
}

References _hash_dropscanbuf(), _hash_kill_items(), fb(), HashScanPosIsValid, IndexScanDescData::indexRelation, IndexScanDescData::opaque, and pfree().

Referenced by hashhandler().

hashgetbitmap()

int64 hashgetbitmap	(	IndexScanDesc	scan,
		TIDBitmap *	tbm
	)

Definition at line 354 of file hash.c.

{
    HashScanOpaque so = (HashScanOpaque) scan->opaque;
    bool        res;
    int64       ntids = 0;
    HashScanPosItem *currItem;
 
    res = _hash_first(scan, ForwardScanDirection);
 
    while (res)
    {
        currItem = &so->currPos.items[so->currPos.itemIndex];
 
        /*
         * _hash_first and _hash_next handle eliminate dead index entries
         * whenever scan->ignore_killed_tuples is true.  Therefore, there's
         * nothing to do here except add the results to the TIDBitmap.
         */
        tbm_add_tuples(tbm, &(currItem->heapTid), 1, true);
        ntids++;
 
        res = _hash_next(scan, ForwardScanDirection);
    }
 
    return ntids;
}

References _hash_first(), _hash_next(), fb(), ForwardScanDirection, IndexScanDescData::opaque, and tbm_add_tuples().

Referenced by hashhandler().

hashgettuple()

bool hashgettuple	(	IndexScanDesc	scan,
		ScanDirection	dir
	)

Definition at line 303 of file hash.c.

{
    HashScanOpaque so = (HashScanOpaque) scan->opaque;
    bool        res;
 
    /* Hash indexes are always lossy since we store only the hash code */
    scan->xs_recheck = true;
 
    /*
     * 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 a routine to
     * get the first item in the scan.
     */
    if (!HashScanPosIsValid(so->currPos))
        res = _hash_first(scan, dir);
    else
    {
        /*
         * Check to see if we should kill the previously-fetched tuple.
         */
        if (scan->kill_prior_tuple)
        {
            /*
             * Yes, so remember it for later. (We'll deal with all such tuples
             * at once right after leaving the index page or at end of scan.)
             * In case if caller reverses the indexscan direction it is quite
             * possible that the same item might get entered multiple times.
             * But, we don't detect that; instead, we just forget any excess
             * entries.
             */
            if (so->killedItems == NULL)
                so->killedItems = palloc_array(int, MaxIndexTuplesPerPage);
 
            if (so->numKilled < MaxIndexTuplesPerPage)
                so->killedItems[so->numKilled++] = so->currPos.itemIndex;
        }
 
        /*
         * Now continue the scan.
         */
        res = _hash_next(scan, dir);
    }
 
    return res;
}

References _hash_first(), _hash_next(), fb(), HashScanPosIsValid, IndexScanDescData::kill_prior_tuple, MaxIndexTuplesPerPage, IndexScanDescData::opaque, palloc_array, and IndexScanDescData::xs_recheck.

Referenced by hashhandler().

hashhandler()

Datum hashhandler

(

PG_FUNCTION_ARGS

)

Definition at line 70 of file hash.c.

{
    static const IndexAmRoutine amroutine = {
        .type = T_IndexAmRoutine,
        .amstrategies = HTMaxStrategyNumber,
        .amsupport = HASHNProcs,
        .amoptsprocnum = HASHOPTIONS_PROC,
        .amcanorder = false,
        .amcanorderbyop = false,
        .amcanhash = true,
        .amconsistentequality = true,
        .amconsistentordering = false,
        .amcanbackward = true,
        .amcanunique = false,
        .amcanmulticol = false,
        .amoptionalkey = false,
        .amsearcharray = false,
        .amsearchnulls = false,
        .amstorage = false,
        .amclusterable = false,
        .ampredlocks = true,
        .amcanparallel = false,
        .amcanbuildparallel = false,
        .amcaninclude = false,
        .amusemaintenanceworkmem = false,
        .amsummarizing = false,
        .amparallelvacuumoptions =
        VACUUM_OPTION_PARALLEL_BULKDEL,
        .amkeytype = INT4OID,
 
        .ambuild = hashbuild,
        .ambuildempty = hashbuildempty,
        .aminsert = hashinsert,
        .aminsertcleanup = NULL,
        .ambulkdelete = hashbulkdelete,
        .amvacuumcleanup = hashvacuumcleanup,
        .amcanreturn = NULL,
        .amcostestimate = hashcostestimate,
        .amgettreeheight = NULL,
        .amoptions = hashoptions,
        .amproperty = NULL,
        .ambuildphasename = NULL,
        .amvalidate = hashvalidate,
        .amadjustmembers = hashadjustmembers,
        .ambeginscan = hashbeginscan,
        .amrescan = hashrescan,
        .amgettuple = hashgettuple,
        .amgetbitmap = hashgetbitmap,
        .amendscan = hashendscan,
        .ammarkpos = NULL,
        .amrestrpos = NULL,
        .amestimateparallelscan = NULL,
        .aminitparallelscan = NULL,
        .amparallelrescan = NULL,
        .amtranslatestrategy = hashtranslatestrategy,
        .amtranslatecmptype = hashtranslatecmptype,
    };
 
    PG_RETURN_POINTER(&amroutine);
}

References fb(), hashadjustmembers(), hashbeginscan(), hashbuild(), hashbuildempty(), hashbulkdelete(), hashcostestimate(), hashendscan(), hashgetbitmap(), hashgettuple(), hashinsert(), HASHNProcs, hashoptions(), HASHOPTIONS_PROC, hashrescan(), hashtranslatecmptype(), hashtranslatestrategy(), hashvacuumcleanup(), hashvalidate(), HTMaxStrategyNumber, PG_RETURN_POINTER, IndexAmRoutine::type, and VACUUM_OPTION_PARALLEL_BULKDEL.

hashinsert()

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

Definition at line 271 of file hash.c.

{
    Datum       index_values[1];
    bool        index_isnull[1];
    IndexTuple  itup;
 
    /* convert data to a hash key; on failure, do not insert anything */
    if (!_hash_convert_tuple(rel,
                             values, isnull,
                             index_values, index_isnull))
        return false;
 
    /* form an index tuple and point it at the heap tuple */
    itup = index_form_tuple(RelationGetDescr(rel), index_values, index_isnull);
    itup->t_tid = *ht_ctid;
 
    _hash_doinsert(rel, itup, heapRel, false);
 
    pfree(itup);
 
    return false;
}

References _hash_convert_tuple(), _hash_doinsert(), fb(), index_form_tuple(), pfree(), RelationGetDescr, IndexTupleData::t_tid, and values.

Referenced by hashhandler().

hashrescan()

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

Definition at line 416 of file hash.c.

{
    HashScanOpaque so = (HashScanOpaque) scan->opaque;
    Relation    rel = scan->indexRelation;
 
    if (HashScanPosIsValid(so->currPos))
    {
        /* Before leaving current page, deal with any killed items */
        if (so->numKilled > 0)
            _hash_kill_items(scan);
    }
 
    _hash_dropscanbuf(rel, so);
 
    /* set position invalid (this will cause _hash_first call) */
    HashScanPosInvalidate(so->currPos);
 
    /* Update scan key, if a new one is given */
    if (scankey && scan->numberOfKeys > 0)
        memcpy(scan->keyData, scankey, scan->numberOfKeys * sizeof(ScanKeyData));
 
    so->hashso_buc_populated = false;
    so->hashso_buc_split = false;
}

References _hash_dropscanbuf(), _hash_kill_items(), fb(), HashScanPosInvalidate, HashScanPosIsValid, IndexScanDescData::indexRelation, IndexScanDescData::keyData, IndexScanDescData::numberOfKeys, and IndexScanDescData::opaque.

Referenced by hashhandler().

hashtranslatecmptype()

StrategyNumber hashtranslatecmptype	(	CompareType	cmptype,
		Oid	opfamily
	)

Definition at line 1022 of file hash.c.

{
    if (cmptype == COMPARE_EQ)
        return HTEqualStrategyNumber;
    return InvalidStrategy;
}

References COMPARE_EQ, HTEqualStrategyNumber, and InvalidStrategy.

Referenced by hashhandler().

hashtranslatestrategy()

CompareType hashtranslatestrategy	(	StrategyNumber	strategy,
		Oid	opfamily
	)

Definition at line 1014 of file hash.c.

{
    if (strategy == HTEqualStrategyNumber)
        return COMPARE_EQ;
    return COMPARE_INVALID;
}

References COMPARE_EQ, COMPARE_INVALID, and HTEqualStrategyNumber.

Referenced by hashhandler().

hashvacuumcleanup()

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

Definition at line 728 of file hash.c.

{
    Relation    rel = info->index;
    BlockNumber num_pages;
 
    /* If hashbulkdelete wasn't called, return NULL signifying no change */
    /* Note: this covers the analyze_only case too */
    if (stats == NULL)
        return NULL;
 
    /* update statistics */
    num_pages = RelationGetNumberOfBlocks(rel);
    stats->num_pages = num_pages;
 
    return stats;
}

References fb(), IndexVacuumInfo::index, IndexBulkDeleteResult::num_pages, and RelationGetNumberOfBlocks.

Referenced by hashhandler().