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Add an executor aminsert() hint mechanism that informs index AMs that the incoming index tuple (the tuple that accompanies the hint) is not being inserted by execution of an SQL statement that logically modifies any of the index's key columns. The hint is received by indexes when an UPDATE takes place that does not apply an optimization like heapam's HOT (though only for indexes where all key columns are logically unchanged). Any index tuple that receives the hint on insert is expected to be a duplicate of at least one existing older version that is needed for the same logical row. Related versions will typically be stored on the same index page, at least within index AMs that apply the hint. Recognizing the difference between MVCC version churn duplicates and true logical row duplicates at the index AM level can help with cleanup of garbage index tuples. Cleanup can intelligently target tuples that are likely to be garbage, without wasting too many cycles on less promising tuples/pages (index pages with little or no version churn). This is infrastructure for an upcoming commit that will teach nbtree to perform bottom-up index deletion. No index AM actually applies the hint just yet. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Victor Yegorov <vyegorov@gmail.com> Discussion: https://postgr.es/m/CAH2-Wz=CEKFa74EScx_hFVshCOn6AA5T-ajFASTdzipdkLTNQQ@mail.gmail.com
217 lines
7.0 KiB
C
217 lines
7.0 KiB
C
/*-------------------------------------------------------------------------
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*
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* bloom.h
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* Header for bloom index.
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*
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* Copyright (c) 2016-2021, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* contrib/bloom/bloom.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef _BLOOM_H_
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#define _BLOOM_H_
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#include "access/amapi.h"
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#include "access/generic_xlog.h"
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#include "access/itup.h"
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#include "access/xlog.h"
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#include "fmgr.h"
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#include "nodes/pathnodes.h"
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/* Support procedures numbers */
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#define BLOOM_HASH_PROC 1
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#define BLOOM_OPTIONS_PROC 2
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#define BLOOM_NPROC 2
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/* Scan strategies */
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#define BLOOM_EQUAL_STRATEGY 1
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#define BLOOM_NSTRATEGIES 1
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/* Opaque for bloom pages */
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typedef struct BloomPageOpaqueData
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{
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OffsetNumber maxoff; /* number of index tuples on page */
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uint16 flags; /* see bit definitions below */
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uint16 unused; /* placeholder to force maxaligning of size of
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* BloomPageOpaqueData and to place
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* bloom_page_id exactly at the end of page */
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uint16 bloom_page_id; /* for identification of BLOOM indexes */
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} BloomPageOpaqueData;
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typedef BloomPageOpaqueData *BloomPageOpaque;
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/* Bloom page flags */
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#define BLOOM_META (1<<0)
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#define BLOOM_DELETED (2<<0)
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/*
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* The page ID is for the convenience of pg_filedump and similar utilities,
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* which otherwise would have a hard time telling pages of different index
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* types apart. It should be the last 2 bytes on the page. This is more or
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* less "free" due to alignment considerations.
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*
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* See comments above GinPageOpaqueData.
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*/
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#define BLOOM_PAGE_ID 0xFF83
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/* Macros for accessing bloom page structures */
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#define BloomPageGetOpaque(page) ((BloomPageOpaque) PageGetSpecialPointer(page))
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#define BloomPageGetMaxOffset(page) (BloomPageGetOpaque(page)->maxoff)
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#define BloomPageIsMeta(page) \
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((BloomPageGetOpaque(page)->flags & BLOOM_META) != 0)
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#define BloomPageIsDeleted(page) \
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((BloomPageGetOpaque(page)->flags & BLOOM_DELETED) != 0)
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#define BloomPageSetDeleted(page) \
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(BloomPageGetOpaque(page)->flags |= BLOOM_DELETED)
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#define BloomPageSetNonDeleted(page) \
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(BloomPageGetOpaque(page)->flags &= ~BLOOM_DELETED)
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#define BloomPageGetData(page) ((BloomTuple *)PageGetContents(page))
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#define BloomPageGetTuple(state, page, offset) \
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((BloomTuple *)(PageGetContents(page) \
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+ (state)->sizeOfBloomTuple * ((offset) - 1)))
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#define BloomPageGetNextTuple(state, tuple) \
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((BloomTuple *)((Pointer)(tuple) + (state)->sizeOfBloomTuple))
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/* Preserved page numbers */
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#define BLOOM_METAPAGE_BLKNO (0)
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#define BLOOM_HEAD_BLKNO (1) /* first data page */
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/*
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* We store Bloom signatures as arrays of uint16 words.
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*/
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typedef uint16 BloomSignatureWord;
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#define SIGNWORDBITS ((int) (BITS_PER_BYTE * sizeof(BloomSignatureWord)))
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/*
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* Default and maximum Bloom signature length in bits.
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*/
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#define DEFAULT_BLOOM_LENGTH (5 * SIGNWORDBITS)
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#define MAX_BLOOM_LENGTH (256 * SIGNWORDBITS)
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/*
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* Default and maximum signature bits generated per index key.
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*/
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#define DEFAULT_BLOOM_BITS 2
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#define MAX_BLOOM_BITS (MAX_BLOOM_LENGTH - 1)
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/* Bloom index options */
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typedef struct BloomOptions
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{
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int32 vl_len_; /* varlena header (do not touch directly!) */
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int bloomLength; /* length of signature in words (not bits!) */
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int bitSize[INDEX_MAX_KEYS]; /* # of bits generated for each
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* index key */
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} BloomOptions;
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/*
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* FreeBlockNumberArray - array of block numbers sized so that metadata fill
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* all space in metapage.
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*/
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typedef BlockNumber FreeBlockNumberArray[
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MAXALIGN_DOWN(
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BLCKSZ - SizeOfPageHeaderData - MAXALIGN(sizeof(BloomPageOpaqueData))
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- MAXALIGN(sizeof(uint16) * 2 + sizeof(uint32) + sizeof(BloomOptions))
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) / sizeof(BlockNumber)
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];
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/* Metadata of bloom index */
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typedef struct BloomMetaPageData
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{
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uint32 magickNumber;
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uint16 nStart;
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uint16 nEnd;
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BloomOptions opts;
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FreeBlockNumberArray notFullPage;
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} BloomMetaPageData;
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/* Magic number to distinguish bloom pages among anothers */
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#define BLOOM_MAGICK_NUMBER (0xDBAC0DED)
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/* Number of blocks numbers fit in BloomMetaPageData */
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#define BloomMetaBlockN (sizeof(FreeBlockNumberArray) / sizeof(BlockNumber))
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#define BloomPageGetMeta(page) ((BloomMetaPageData *) PageGetContents(page))
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typedef struct BloomState
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{
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FmgrInfo hashFn[INDEX_MAX_KEYS];
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Oid collations[INDEX_MAX_KEYS];
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BloomOptions opts; /* copy of options on index's metapage */
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int32 nColumns;
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/*
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* sizeOfBloomTuple is index-specific, and it depends on reloptions, so
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* precompute it
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*/
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Size sizeOfBloomTuple;
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} BloomState;
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#define BloomPageGetFreeSpace(state, page) \
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(BLCKSZ - MAXALIGN(SizeOfPageHeaderData) \
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- BloomPageGetMaxOffset(page) * (state)->sizeOfBloomTuple \
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- MAXALIGN(sizeof(BloomPageOpaqueData)))
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/*
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* Tuples are very different from all other relations
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*/
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typedef struct BloomTuple
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{
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ItemPointerData heapPtr;
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BloomSignatureWord sign[FLEXIBLE_ARRAY_MEMBER];
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} BloomTuple;
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#define BLOOMTUPLEHDRSZ offsetof(BloomTuple, sign)
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/* Opaque data structure for bloom index scan */
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typedef struct BloomScanOpaqueData
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{
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BloomSignatureWord *sign; /* Scan signature */
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BloomState state;
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} BloomScanOpaqueData;
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typedef BloomScanOpaqueData *BloomScanOpaque;
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/* blutils.c */
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extern void _PG_init(void);
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extern void initBloomState(BloomState *state, Relation index);
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extern void BloomFillMetapage(Relation index, Page metaPage);
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extern void BloomInitMetapage(Relation index);
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extern void BloomInitPage(Page page, uint16 flags);
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extern Buffer BloomNewBuffer(Relation index);
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extern void signValue(BloomState *state, BloomSignatureWord *sign, Datum value, int attno);
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extern BloomTuple *BloomFormTuple(BloomState *state, ItemPointer iptr, Datum *values, bool *isnull);
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extern bool BloomPageAddItem(BloomState *state, Page page, BloomTuple *tuple);
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/* blvalidate.c */
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extern bool blvalidate(Oid opclassoid);
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/* index access method interface functions */
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extern bool blinsert(Relation index, Datum *values, bool *isnull,
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ItemPointer ht_ctid, Relation heapRel,
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IndexUniqueCheck checkUnique,
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bool indexUnchanged,
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struct IndexInfo *indexInfo);
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extern IndexScanDesc blbeginscan(Relation r, int nkeys, int norderbys);
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extern int64 blgetbitmap(IndexScanDesc scan, TIDBitmap *tbm);
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extern void blrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
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ScanKey orderbys, int norderbys);
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extern void blendscan(IndexScanDesc scan);
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extern IndexBuildResult *blbuild(Relation heap, Relation index,
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struct IndexInfo *indexInfo);
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extern void blbuildempty(Relation index);
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extern IndexBulkDeleteResult *blbulkdelete(IndexVacuumInfo *info,
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IndexBulkDeleteResult *stats, IndexBulkDeleteCallback callback,
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void *callback_state);
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extern IndexBulkDeleteResult *blvacuumcleanup(IndexVacuumInfo *info,
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IndexBulkDeleteResult *stats);
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extern bytea *bloptions(Datum reloptions, bool validate);
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extern void blcostestimate(PlannerInfo *root, IndexPath *path,
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double loop_count, Cost *indexStartupCost,
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Cost *indexTotalCost, Selectivity *indexSelectivity,
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double *indexCorrelation, double *indexPages);
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#endif
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