1 /*-------------------------------------------------------------------------
2  *
3  * bloom.h
4  *	  Header for bloom index.
5  *
6  * Copyright (c) 2016-2020, PostgreSQL Global Development Group
7  *
8  * IDENTIFICATION
9  *	  contrib/bloom/bloom.h
10  *
11  *-------------------------------------------------------------------------
12  */
13 #ifndef _BLOOM_H_
14 #define _BLOOM_H_
15 
16 #include "access/amapi.h"
17 #include "access/generic_xlog.h"
18 #include "access/itup.h"
19 #include "access/xlog.h"
20 #include "fmgr.h"
21 #include "nodes/pathnodes.h"
22 
23 /* Support procedures numbers */
24 #define BLOOM_HASH_PROC			1
25 #define BLOOM_OPTIONS_PROC		2
26 #define BLOOM_NPROC				2
27 
28 /* Scan strategies */
29 #define BLOOM_EQUAL_STRATEGY	1
30 #define BLOOM_NSTRATEGIES		1
31 
32 /* Opaque for bloom pages */
33 typedef struct BloomPageOpaqueData
34 {
35 	OffsetNumber maxoff;		/* number of index tuples on page */
36 	uint16		flags;			/* see bit definitions below */
37 	uint16		unused;			/* placeholder to force maxaligning of size of
38 								 * BloomPageOpaqueData and to place
39 								 * bloom_page_id exactly at the end of page */
40 	uint16		bloom_page_id;	/* for identification of BLOOM indexes */
41 } BloomPageOpaqueData;
42 
43 typedef BloomPageOpaqueData *BloomPageOpaque;
44 
45 /* Bloom page flags */
46 #define BLOOM_META		(1<<0)
47 #define BLOOM_DELETED	(2<<0)
48 
49 /*
50  * The page ID is for the convenience of pg_filedump and similar utilities,
51  * which otherwise would have a hard time telling pages of different index
52  * types apart.  It should be the last 2 bytes on the page.  This is more or
53  * less "free" due to alignment considerations.
54  *
55  * See comments above GinPageOpaqueData.
56  */
57 #define BLOOM_PAGE_ID		0xFF83
58 
59 /* Macros for accessing bloom page structures */
60 #define BloomPageGetOpaque(page) ((BloomPageOpaque) PageGetSpecialPointer(page))
61 #define BloomPageGetMaxOffset(page) (BloomPageGetOpaque(page)->maxoff)
62 #define BloomPageIsMeta(page) \
63 	((BloomPageGetOpaque(page)->flags & BLOOM_META) != 0)
64 #define BloomPageIsDeleted(page) \
65 	((BloomPageGetOpaque(page)->flags & BLOOM_DELETED) != 0)
66 #define BloomPageSetDeleted(page) \
67 	(BloomPageGetOpaque(page)->flags |= BLOOM_DELETED)
68 #define BloomPageSetNonDeleted(page) \
69 	(BloomPageGetOpaque(page)->flags &= ~BLOOM_DELETED)
70 #define BloomPageGetData(page)		((BloomTuple *)PageGetContents(page))
71 #define BloomPageGetTuple(state, page, offset) \
72 	((BloomTuple *)(PageGetContents(page) \
73 		+ (state)->sizeOfBloomTuple * ((offset) - 1)))
74 #define BloomPageGetNextTuple(state, tuple) \
75 	((BloomTuple *)((Pointer)(tuple) + (state)->sizeOfBloomTuple))
76 
77 /* Preserved page numbers */
78 #define BLOOM_METAPAGE_BLKNO	(0)
79 #define BLOOM_HEAD_BLKNO		(1) /* first data page */
80 
81 /*
82  * We store Bloom signatures as arrays of uint16 words.
83  */
84 typedef uint16 BloomSignatureWord;
85 
86 #define SIGNWORDBITS ((int) (BITS_PER_BYTE * sizeof(BloomSignatureWord)))
87 
88 /*
89  * Default and maximum Bloom signature length in bits.
90  */
91 #define DEFAULT_BLOOM_LENGTH	(5 * SIGNWORDBITS)
92 #define MAX_BLOOM_LENGTH		(256 * SIGNWORDBITS)
93 
94 /*
95  * Default and maximum signature bits generated per index key.
96  */
97 #define DEFAULT_BLOOM_BITS		2
98 #define MAX_BLOOM_BITS			(MAX_BLOOM_LENGTH - 1)
99 
100 /* Bloom index options */
101 typedef struct BloomOptions
102 {
103 	int32		vl_len_;		/* varlena header (do not touch directly!) */
104 	int			bloomLength;	/* length of signature in words (not bits!) */
105 	int			bitSize[INDEX_MAX_KEYS];	/* # of bits generated for each
106 											 * index key */
107 } BloomOptions;
108 
109 /*
110  * FreeBlockNumberArray - array of block numbers sized so that metadata fill
111  * all space in metapage.
112  */
113 typedef BlockNumber FreeBlockNumberArray[
114 										 MAXALIGN_DOWN(
115 													   BLCKSZ - SizeOfPageHeaderData - MAXALIGN(sizeof(BloomPageOpaqueData))
116 													   - MAXALIGN(sizeof(uint16) * 2 + sizeof(uint32) + sizeof(BloomOptions))
117 													   ) / sizeof(BlockNumber)
118 ];
119 
120 /* Metadata of bloom index */
121 typedef struct BloomMetaPageData
122 {
123 	uint32		magickNumber;
124 	uint16		nStart;
125 	uint16		nEnd;
126 	BloomOptions opts;
127 	FreeBlockNumberArray notFullPage;
128 } BloomMetaPageData;
129 
130 /* Magic number to distinguish bloom pages among anothers */
131 #define BLOOM_MAGICK_NUMBER (0xDBAC0DED)
132 
133 /* Number of blocks numbers fit in BloomMetaPageData */
134 #define BloomMetaBlockN		(sizeof(FreeBlockNumberArray) / sizeof(BlockNumber))
135 
136 #define BloomPageGetMeta(page)	((BloomMetaPageData *) PageGetContents(page))
137 
138 typedef struct BloomState
139 {
140 	FmgrInfo	hashFn[INDEX_MAX_KEYS];
141 	Oid			collations[INDEX_MAX_KEYS];
142 	BloomOptions opts;			/* copy of options on index's metapage */
143 	int32		nColumns;
144 
145 	/*
146 	 * sizeOfBloomTuple is index-specific, and it depends on reloptions, so
147 	 * precompute it
148 	 */
149 	Size		sizeOfBloomTuple;
150 } BloomState;
151 
152 #define BloomPageGetFreeSpace(state, page) \
153 	(BLCKSZ - MAXALIGN(SizeOfPageHeaderData) \
154 		- BloomPageGetMaxOffset(page) * (state)->sizeOfBloomTuple \
155 		- MAXALIGN(sizeof(BloomPageOpaqueData)))
156 
157 /*
158  * Tuples are very different from all other relations
159  */
160 typedef struct BloomTuple
161 {
162 	ItemPointerData heapPtr;
163 	BloomSignatureWord sign[FLEXIBLE_ARRAY_MEMBER];
164 } BloomTuple;
165 
166 #define BLOOMTUPLEHDRSZ offsetof(BloomTuple, sign)
167 
168 /* Opaque data structure for bloom index scan */
169 typedef struct BloomScanOpaqueData
170 {
171 	BloomSignatureWord *sign;	/* Scan signature */
172 	BloomState	state;
173 } BloomScanOpaqueData;
174 
175 typedef BloomScanOpaqueData *BloomScanOpaque;
176 
177 /* blutils.c */
178 extern void _PG_init(void);
179 extern void initBloomState(BloomState *state, Relation index);
180 extern void BloomFillMetapage(Relation index, Page metaPage);
181 extern void BloomInitMetapage(Relation index);
182 extern void BloomInitPage(Page page, uint16 flags);
183 extern Buffer BloomNewBuffer(Relation index);
184 extern void signValue(BloomState *state, BloomSignatureWord *sign, Datum value, int attno);
185 extern BloomTuple *BloomFormTuple(BloomState *state, ItemPointer iptr, Datum *values, bool *isnull);
186 extern bool BloomPageAddItem(BloomState *state, Page page, BloomTuple *tuple);
187 
188 /* blvalidate.c */
189 extern bool blvalidate(Oid opclassoid);
190 
191 /* index access method interface functions */
192 extern bool blinsert(Relation index, Datum *values, bool *isnull,
193 					 ItemPointer ht_ctid, Relation heapRel,
194 					 IndexUniqueCheck checkUnique,
195 					 struct IndexInfo *indexInfo);
196 extern IndexScanDesc blbeginscan(Relation r, int nkeys, int norderbys);
197 extern int64 blgetbitmap(IndexScanDesc scan, TIDBitmap *tbm);
198 extern void blrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
199 					 ScanKey orderbys, int norderbys);
200 extern void blendscan(IndexScanDesc scan);
201 extern IndexBuildResult *blbuild(Relation heap, Relation index,
202 								 struct IndexInfo *indexInfo);
203 extern void blbuildempty(Relation index);
204 extern IndexBulkDeleteResult *blbulkdelete(IndexVacuumInfo *info,
205 										   IndexBulkDeleteResult *stats, IndexBulkDeleteCallback callback,
206 										   void *callback_state);
207 extern IndexBulkDeleteResult *blvacuumcleanup(IndexVacuumInfo *info,
208 											  IndexBulkDeleteResult *stats);
209 extern bytea *bloptions(Datum reloptions, bool validate);
210 extern void blcostestimate(PlannerInfo *root, IndexPath *path,
211 						   double loop_count, Cost *indexStartupCost,
212 						   Cost *indexTotalCost, Selectivity *indexSelectivity,
213 						   double *indexCorrelation, double *indexPages);
214 
215 #endif
216