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postgresql/contrib/bloom/bloom.h
Tom Lane ee4af347ba Measure Bloom index signature-length reloption in bits, not words. 
Per discussion, this is a more understandable and future-proof way of
exposing the setting to users.  On-disk, we can still store it in words,
so as to not break on-disk compatibility with beta1.

Along the way, clean up the code associated with Bloom reloptions.
Provide explicit macros for default and maximum lengths rather than
having magic numbers buried in multiple places in the code.  Drop
the adjustBloomOptions() code altogether: it was useless in view of
the fact that reloptions.c already performed default-substitution and
range checking for the options.  Rename a couple of macros and types
for more clarity.

Discussion: <23767.1464926580@sss.pgh.pa.us>
2016-06-03 10:52:45 -04:00

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/*-------------------------------------------------------------------------
*
* bloom.h
* Header for bloom index.
*
* Copyright (c) 2016, PostgreSQL Global Development Group
*
* IDENTIFICATION
* contrib/bloom/bloom.h
*
*-------------------------------------------------------------------------
*/
#ifndef _BLOOM_H_
#define _BLOOM_H_
#include "access/amapi.h"
#include "access/generic_xlog.h"
#include "access/itup.h"
#include "access/xlog.h"
#include "nodes/relation.h"
#include "fmgr.h"
/* Support procedures numbers */
#define BLOOM_HASH_PROC 1
#define BLOOM_NPROC 1
/* Scan strategies */
#define BLOOM_EQUAL_STRATEGY 1
#define BLOOM_NSTRATEGIES 1
/* Opaque for bloom pages */
typedef struct BloomPageOpaqueData
{
OffsetNumber maxoff; /* number of index tuples on page */
uint16 flags; /* see bit definitions below */
uint16 unused; /* placeholder to force maxaligning of size
* of BloomPageOpaqueData and to place
* bloom_page_id exactly at the end of page
*/
uint16 bloom_page_id; /* for identification of BLOOM indexes */
} BloomPageOpaqueData;
typedef BloomPageOpaqueData *BloomPageOpaque;
/* Bloom page flags */
#define BLOOM_META (1<<0)
#define BLOOM_DELETED (2<<0)
/*
* The page ID is for the convenience of pg_filedump and similar utilities,
* which otherwise would have a hard time telling pages of different index
* types apart. It should be the last 2 bytes on the page. This is more or
* less "free" due to alignment considerations.
*
* See comments above GinPageOpaqueData.
*/
#define BLOOM_PAGE_ID 0xFF83
/* Macros for accessing bloom page structures */
#define BloomPageGetOpaque(page) ((BloomPageOpaque) PageGetSpecialPointer(page))
#define BloomPageGetMaxOffset(page) (BloomPageGetOpaque(page)->maxoff)
#define BloomPageIsMeta(page) \
((BloomPageGetOpaque(page)->flags & BLOOM_META) != 0)
#define BloomPageIsDeleted(page) \
((BloomPageGetOpaque(page)->flags & BLOOM_DELETED) != 0)
#define BloomPageSetDeleted(page) \
(BloomPageGetOpaque(page)->flags |= BLOOM_DELETED)
#define BloomPageSetNonDeleted(page) \
(BloomPageGetOpaque(page)->flags &= ~BLOOM_DELETED)
#define BloomPageGetData(page) ((BloomTuple *)PageGetContents(page))
#define BloomPageGetTuple(state, page, offset) \
((BloomTuple *)(PageGetContents(page) \
+ (state)->sizeOfBloomTuple * ((offset) - 1)))
#define BloomPageGetNextTuple(state, tuple) \
((BloomTuple *)((Pointer)(tuple) + (state)->sizeOfBloomTuple))
/* Preserved page numbers */
#define BLOOM_METAPAGE_BLKNO (0)
#define BLOOM_HEAD_BLKNO (1) /* first data page */
/*
* We store Bloom signatures as arrays of uint16 words.
*/
typedef uint16 BloomSignatureWord;
#define SIGNWORDBITS ((int) (BITS_PER_BYTE * sizeof(BloomSignatureWord)))
/*
* Default and maximum Bloom signature length in bits.
*/
#define DEFAULT_BLOOM_LENGTH (5 * SIGNWORDBITS)
#define MAX_BLOOM_LENGTH (256 * SIGNWORDBITS)
/*
* Default and maximum signature bits generated per index key.
*/
#define DEFAULT_BLOOM_BITS 2
#define MAX_BLOOM_BITS (MAX_BLOOM_LENGTH - 1)
/* Bloom index options */
typedef struct BloomOptions
{
int32 vl_len_; /* varlena header (do not touch directly!) */
int bloomLength; /* length of signature in words (not bits!) */
int bitSize[INDEX_MAX_KEYS]; /* # of bits generated for each
* index key */
} BloomOptions;
/*
* FreeBlockNumberArray - array of block numbers sized so that metadata fill
* all space in metapage.
*/
typedef BlockNumber FreeBlockNumberArray[
MAXALIGN_DOWN(
BLCKSZ - SizeOfPageHeaderData - MAXALIGN(sizeof(BloomPageOpaqueData))
- MAXALIGN(sizeof(uint16) * 2 + sizeof(uint32) + sizeof(BloomOptions))
) / sizeof(BlockNumber)
];
/* Metadata of bloom index */
typedef struct BloomMetaPageData
{
uint32 magickNumber;
uint16 nStart;
uint16 nEnd;
BloomOptions opts;
FreeBlockNumberArray notFullPage;
} BloomMetaPageData;
/* Magic number to distinguish bloom pages among anothers */
#define BLOOM_MAGICK_NUMBER (0xDBAC0DED)
/* Number of blocks numbers fit in BloomMetaPageData */
#define BloomMetaBlockN (sizeof(FreeBlockNumberArray) / sizeof(BlockNumber))
#define BloomPageGetMeta(page) ((BloomMetaPageData *) PageGetContents(page))
typedef struct BloomState
{
FmgrInfo hashFn[INDEX_MAX_KEYS];
BloomOptions opts; /* copy of options on index's metapage */
int32 nColumns;
/*
* sizeOfBloomTuple is index-specific, and it depends on reloptions, so
* precompute it
*/
Size sizeOfBloomTuple;
} BloomState;
#define BloomPageGetFreeSpace(state, page) \
(BLCKSZ - MAXALIGN(SizeOfPageHeaderData) \
- BloomPageGetMaxOffset(page) * (state)->sizeOfBloomTuple \
- MAXALIGN(sizeof(BloomPageOpaqueData)))
/*
* Tuples are very different from all other relations
*/
typedef struct BloomTuple
{
ItemPointerData heapPtr;
BloomSignatureWord sign[FLEXIBLE_ARRAY_MEMBER];
} BloomTuple;
#define BLOOMTUPLEHDRSZ offsetof(BloomTuple, sign)
/* Opaque data structure for bloom index scan */
typedef struct BloomScanOpaqueData
{
BloomSignatureWord *sign; /* Scan signature */
BloomState state;
} BloomScanOpaqueData;
typedef BloomScanOpaqueData *BloomScanOpaque;
/* blutils.c */
extern void _PG_init(void);
extern Datum blhandler(PG_FUNCTION_ARGS);
extern void initBloomState(BloomState * state, Relation index);
extern void BloomFillMetapage(Relation index, Page metaPage);
extern void BloomInitMetapage(Relation index);
extern void BloomInitPage(Page page, uint16 flags);
extern Buffer BloomNewBuffer(Relation index);
extern void signValue(BloomState * state, BloomSignatureWord * sign, Datum value, int attno);
extern BloomTuple *BloomFormTuple(BloomState * state, ItemPointer iptr, Datum *values, bool *isnull);
extern bool BloomPageAddItem(BloomState * state, Page page, BloomTuple * tuple);
/* blvalidate.c */
extern bool blvalidate(Oid opclassoid);
/* index access method interface functions */
extern bool blinsert(Relation index, Datum *values, bool *isnull,
ItemPointer ht_ctid, Relation heapRel,
IndexUniqueCheck checkUnique);
extern IndexScanDesc blbeginscan(Relation r, int nkeys, int norderbys);
extern int64 blgetbitmap(IndexScanDesc scan, TIDBitmap *tbm);
extern void blrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
ScanKey orderbys, int norderbys);
extern void blendscan(IndexScanDesc scan);
extern IndexBuildResult *blbuild(Relation heap, Relation index,
struct IndexInfo *indexInfo);
extern void blbuildempty(Relation index);
extern IndexBulkDeleteResult *blbulkdelete(IndexVacuumInfo *info,
IndexBulkDeleteResult *stats, IndexBulkDeleteCallback callback,
void *callback_state);
extern IndexBulkDeleteResult *blvacuumcleanup(IndexVacuumInfo *info,
IndexBulkDeleteResult *stats);
extern bytea *bloptions(Datum reloptions, bool validate);
extern void blcostestimate(PlannerInfo *root, IndexPath *path,
double loop_count, Cost *indexStartupCost,
Cost *indexTotalCost, Selectivity *indexSelectivity,
double *indexCorrelation);
#endif
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