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8b65cf4c5e
This patch is a no-op patch which is intended to reduce the chances of failures of omission once the functional part of the "snapshot too old" patch goes in. It adds parameters for snapshot, relation, and an enum to specify whether the snapshot age check needs to be done for the page at this point. This initial patch passes NULL for the first two new parameters and BGP_NO_SNAPSHOT_TEST for the third. The follow-on patch will change the places where the test needs to be made.
179 lines
3.5 KiB
C
179 lines
3.5 KiB
C
/*-------------------------------------------------------------------------
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*
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* blscan.c
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* Bloom index scan functions.
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*
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* Copyright (c) 2016, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* contrib/bloom/blscan.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "access/relscan.h"
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#include "pgstat.h"
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#include "miscadmin.h"
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#include "storage/bufmgr.h"
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#include "storage/lmgr.h"
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#include "utils/memutils.h"
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#include "utils/rel.h"
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#include "bloom.h"
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/*
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* Begin scan of bloom index.
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*/
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IndexScanDesc
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blbeginscan(Relation r, int nkeys, int norderbys)
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{
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IndexScanDesc scan;
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scan = RelationGetIndexScan(r, nkeys, norderbys);
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return scan;
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}
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/*
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* Rescan a bloom index.
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*/
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void
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blrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
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ScanKey orderbys, int norderbys)
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{
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BloomScanOpaque so;
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so = (BloomScanOpaque) scan->opaque;
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if (so == NULL)
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{
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/* if called from blbeginscan */
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so = (BloomScanOpaque) palloc(sizeof(BloomScanOpaqueData));
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initBloomState(&so->state, scan->indexRelation);
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scan->opaque = so;
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}
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else
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{
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if (so->sign)
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pfree(so->sign);
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}
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so->sign = NULL;
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if (scankey && scan->numberOfKeys > 0)
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{
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memmove(scan->keyData, scankey,
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scan->numberOfKeys * sizeof(ScanKeyData));
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}
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}
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/*
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* End scan of bloom index.
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*/
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void
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blendscan(IndexScanDesc scan)
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{
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BloomScanOpaque so = (BloomScanOpaque) scan->opaque;
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if (so->sign)
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pfree(so->sign);
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so->sign = NULL;
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}
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/*
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* Insert all matching tuples into to a bitmap.
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*/
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int64
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blgetbitmap(IndexScanDesc scan, TIDBitmap *tbm)
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{
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int64 ntids = 0;
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BlockNumber blkno = BLOOM_HEAD_BLKNO,
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npages;
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int i;
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BufferAccessStrategy bas;
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BloomScanOpaque so = (BloomScanOpaque) scan->opaque;
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if (so->sign == NULL)
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{
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/* New search: have to calculate search signature */
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ScanKey skey = scan->keyData;
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so->sign = palloc0(sizeof(SignType) * so->state.opts.bloomLength);
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for (i = 0; i < scan->numberOfKeys; i++)
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{
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/*
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* Assume bloom-indexable operators to be strict, so nothing could
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* be found for NULL key.
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*/
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if (skey->sk_flags & SK_ISNULL)
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{
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pfree(so->sign);
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so->sign = NULL;
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return 0;
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}
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/* Add next value to the signature */
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signValue(&so->state, so->sign, skey->sk_argument,
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skey->sk_attno - 1);
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skey++;
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}
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}
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/*
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* We're going to read the whole index. This is why we use appropriate
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* buffer access strategy.
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*/
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bas = GetAccessStrategy(BAS_BULKREAD);
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npages = RelationGetNumberOfBlocks(scan->indexRelation);
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for (blkno = BLOOM_HEAD_BLKNO; blkno < npages; blkno++)
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{
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Buffer buffer;
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Page page;
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buffer = ReadBufferExtended(scan->indexRelation, MAIN_FORKNUM,
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blkno, RBM_NORMAL, bas);
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LockBuffer(buffer, BUFFER_LOCK_SHARE);
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page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
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if (!BloomPageIsDeleted(page))
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{
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OffsetNumber offset,
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maxOffset = BloomPageGetMaxOffset(page);
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for (offset = 1; offset <= maxOffset; offset++)
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{
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BloomTuple *itup = BloomPageGetTuple(&so->state, page, offset);
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bool res = true;
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/* Check index signature with scan signature */
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for (i = 0; i < so->state.opts.bloomLength; i++)
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{
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if ((itup->sign[i] & so->sign[i]) != so->sign[i])
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{
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res = false;
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break;
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}
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}
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/* Add matching tuples to bitmap */
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if (res)
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{
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tbm_add_tuples(tbm, &itup->heapPtr, 1, true);
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ntids++;
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}
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}
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}
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UnlockReleaseBuffer(buffer);
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CHECK_FOR_INTERRUPTS();
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}
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FreeAccessStrategy(bas);
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return ntids;
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}
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