blscan.c File Reference

#include "postgres.h"
#include "access/relscan.h"
#include "bloom.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "storage/bufmgr.h"

Include dependency graph for blscan.c:

Go to the source code of this file.

Functions
IndexScanDesc	blbeginscan (Relation r, int nkeys, int norderbys)
void	blrescan (IndexScanDesc scan, ScanKey scankey, int nscankeys, ScanKey orderbys, int norderbys)
void	blendscan (IndexScanDesc scan)
int64	blgetbitmap (IndexScanDesc scan, TIDBitmap *tbm)

Function Documentation

blbeginscan()

IndexScanDesc blbeginscan	(	Relation	r,
		int	nkeys,
		int	norderbys
	)

Definition at line 25 of file blscan.c.

{
    IndexScanDesc scan;
    BloomScanOpaque so;
 
    scan = RelationGetIndexScan(r, nkeys, norderbys);
 
    so = (BloomScanOpaque) palloc(sizeof(BloomScanOpaqueData));
    initBloomState(&so->state, scan->indexRelation);
    so->sign = NULL;
 
    scan->opaque = so;
 
    return scan;
}

References IndexScanDescData::indexRelation, initBloomState(), IndexScanDescData::opaque, palloc(), RelationGetIndexScan(), BloomScanOpaqueData::sign, and BloomScanOpaqueData::state.

Referenced by blhandler().

blendscan()

void blendscan

(

IndexScanDesc

scan

)

Definition at line 62 of file blscan.c.

{
    BloomScanOpaque so = (BloomScanOpaque) scan->opaque;
 
    if (so->sign)
        pfree(so->sign);
    so->sign = NULL;
}

References if(), IndexScanDescData::opaque, pfree(), and BloomScanOpaqueData::sign.

Referenced by blhandler().

blgetbitmap()

int64 blgetbitmap	(	IndexScanDesc	scan,
		TIDBitmap *	tbm
	)

Definition at line 75 of file blscan.c.

{
    int64       ntids = 0;
    BlockNumber blkno = BLOOM_HEAD_BLKNO,
                npages;
    int         i;
    BufferAccessStrategy bas;
    BloomScanOpaque so = (BloomScanOpaque) scan->opaque;
 
    if (so->sign == NULL)
    {
        /* New search: have to calculate search signature */
        ScanKey     skey = scan->keyData;
 
        so->sign = palloc0(sizeof(BloomSignatureWord) * so->state.opts.bloomLength);
 
        for (i = 0; i < scan->numberOfKeys; i++)
        {
            /*
             * Assume bloom-indexable operators to be strict, so nothing could
             * be found for NULL key.
             */
            if (skey->sk_flags & SK_ISNULL)
            {
                pfree(so->sign);
                so->sign = NULL;
                return 0;
            }
 
            /* Add next value to the signature */
            signValue(&so->state, so->sign, skey->sk_argument,
                      skey->sk_attno - 1);
 
            skey++;
        }
    }
 
    /*
     * We're going to read the whole index. This is why we use appropriate
     * buffer access strategy.
     */
    bas = GetAccessStrategy(BAS_BULKREAD);
    npages = RelationGetNumberOfBlocks(scan->indexRelation);
    pgstat_count_index_scan(scan->indexRelation);
    if (scan->instrument)
        scan->instrument->nsearches++;
 
    for (blkno = BLOOM_HEAD_BLKNO; blkno < npages; blkno++)
    {
        Buffer      buffer;
        Page        page;
 
        buffer = ReadBufferExtended(scan->indexRelation, MAIN_FORKNUM,
                                    blkno, RBM_NORMAL, bas);
 
        LockBuffer(buffer, BUFFER_LOCK_SHARE);
        page = BufferGetPage(buffer);
 
        if (!PageIsNew(page) && !BloomPageIsDeleted(page))
        {
            OffsetNumber offset,
                        maxOffset = BloomPageGetMaxOffset(page);
 
            for (offset = 1; offset <= maxOffset; offset++)
            {
                BloomTuple *itup = BloomPageGetTuple(&so->state, page, offset);
                bool        res = true;
 
                /* Check index signature with scan signature */
                for (i = 0; i < so->state.opts.bloomLength; i++)
                {
                    if ((itup->sign[i] & so->sign[i]) != so->sign[i])
                    {
                        res = false;
                        break;
                    }
                }
 
                /* Add matching tuples to bitmap */
                if (res)
                {
                    tbm_add_tuples(tbm, &itup->heapPtr, 1, true);
                    ntids++;
                }
            }
        }
 
        UnlockReleaseBuffer(buffer);
        CHECK_FOR_INTERRUPTS();
    }
    FreeAccessStrategy(bas);
 
    return ntids;
}

References BAS_BULKREAD, BLOOM_HEAD_BLKNO, BloomOptions::bloomLength, BloomPageGetMaxOffset, BloomPageGetTuple, BloomPageIsDeleted, BUFFER_LOCK_SHARE, BufferGetPage(), CHECK_FOR_INTERRUPTS, FreeAccessStrategy(), GetAccessStrategy(), BloomTuple::heapPtr, i, if(), IndexScanDescData::indexRelation, IndexScanDescData::instrument, IndexScanDescData::keyData, LockBuffer(), MAIN_FORKNUM, IndexScanInstrumentation::nsearches, IndexScanDescData::numberOfKeys, IndexScanDescData::opaque, BloomState::opts, PageIsNew(), palloc0(), pfree(), pgstat_count_index_scan, RBM_NORMAL, ReadBufferExtended(), RelationGetNumberOfBlocks, BloomTuple::sign, BloomScanOpaqueData::sign, signValue(), ScanKeyData::sk_argument, ScanKeyData::sk_attno, ScanKeyData::sk_flags, SK_ISNULL, BloomScanOpaqueData::state, tbm_add_tuples(), and UnlockReleaseBuffer().

Referenced by blhandler().

blrescan()

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

Definition at line 45 of file blscan.c.

{
    BloomScanOpaque so = (BloomScanOpaque) scan->opaque;
 
    if (so->sign)
        pfree(so->sign);
    so->sign = NULL;
 
    if (scankey && scan->numberOfKeys > 0)
        memcpy(scan->keyData, scankey, scan->numberOfKeys * sizeof(ScanKeyData));
}

References if(), IndexScanDescData::keyData, IndexScanDescData::numberOfKeys, IndexScanDescData::opaque, pfree(), and BloomScanOpaqueData::sign.

Referenced by blhandler().