1 /*------------------------------------------------------------------------- 2 * 3 * spgist_private.h 4 * Private declarations for SP-GiST access method. 5 * 6 * 7 * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group 8 * Portions Copyright (c) 1994, Regents of the University of California 9 * 10 * src/include/access/spgist_private.h 11 * 12 *------------------------------------------------------------------------- 13 */ 14 #ifndef SPGIST_PRIVATE_H 15 #define SPGIST_PRIVATE_H 16 17 #include "access/itup.h" 18 #include "access/spgist.h" 19 #include "nodes/tidbitmap.h" 20 #include "storage/buf.h" 21 #include "utils/relcache.h" 22 23 24 /* Page numbers of fixed-location pages */ 25 #define SPGIST_METAPAGE_BLKNO (0) /* metapage */ 26 #define SPGIST_ROOT_BLKNO (1) /* root for normal entries */ 27 #define SPGIST_NULL_BLKNO (2) /* root for null-value entries */ 28 #define SPGIST_LAST_FIXED_BLKNO SPGIST_NULL_BLKNO 29 30 #define SpGistBlockIsRoot(blkno) \ 31 ((blkno) == SPGIST_ROOT_BLKNO || (blkno) == SPGIST_NULL_BLKNO) 32 #define SpGistBlockIsFixed(blkno) \ 33 ((BlockNumber) (blkno) <= (BlockNumber) SPGIST_LAST_FIXED_BLKNO) 34 35 /* 36 * Contents of page special space on SPGiST index pages 37 */ 38 typedef struct SpGistPageOpaqueData 39 { 40 uint16 flags; /* see bit definitions below */ 41 uint16 nRedirection; /* number of redirection tuples on page */ 42 uint16 nPlaceholder; /* number of placeholder tuples on page */ 43 /* note there's no count of either LIVE or DEAD tuples ... */ 44 uint16 spgist_page_id; /* for identification of SP-GiST indexes */ 45 } SpGistPageOpaqueData; 46 47 typedef SpGistPageOpaqueData *SpGistPageOpaque; 48 49 /* Flag bits in page special space */ 50 #define SPGIST_META (1<<0) 51 #define SPGIST_DELETED (1<<1) /* never set, but keep for backwards 52 * compatibility */ 53 #define SPGIST_LEAF (1<<2) 54 #define SPGIST_NULLS (1<<3) 55 56 #define SpGistPageGetOpaque(page) ((SpGistPageOpaque) PageGetSpecialPointer(page)) 57 #define SpGistPageIsMeta(page) (SpGistPageGetOpaque(page)->flags & SPGIST_META) 58 #define SpGistPageIsDeleted(page) (SpGistPageGetOpaque(page)->flags & SPGIST_DELETED) 59 #define SpGistPageIsLeaf(page) (SpGistPageGetOpaque(page)->flags & SPGIST_LEAF) 60 #define SpGistPageStoresNulls(page) (SpGistPageGetOpaque(page)->flags & SPGIST_NULLS) 61 62 /* 63 * The page ID is for the convenience of pg_filedump and similar utilities, 64 * which otherwise would have a hard time telling pages of different index 65 * types apart. It should be the last 2 bytes on the page. This is more or 66 * less "free" due to alignment considerations. 67 * 68 * See comments above GinPageOpaqueData. 69 */ 70 #define SPGIST_PAGE_ID 0xFF82 71 72 /* 73 * Each backend keeps a cache of last-used page info in its index->rd_amcache 74 * area. This is initialized from, and occasionally written back to, 75 * shared storage in the index metapage. 76 */ 77 typedef struct SpGistLastUsedPage 78 { 79 BlockNumber blkno; /* block number, or InvalidBlockNumber */ 80 int freeSpace; /* page's free space (could be obsolete!) */ 81 } SpGistLastUsedPage; 82 83 /* Note: indexes in cachedPage[] match flag assignments for SpGistGetBuffer */ 84 #define SPGIST_CACHED_PAGES 8 85 86 typedef struct SpGistLUPCache 87 { 88 SpGistLastUsedPage cachedPage[SPGIST_CACHED_PAGES]; 89 } SpGistLUPCache; 90 91 /* 92 * metapage 93 */ 94 typedef struct SpGistMetaPageData 95 { 96 uint32 magicNumber; /* for identity cross-check */ 97 SpGistLUPCache lastUsedPages; /* shared storage of last-used info */ 98 } SpGistMetaPageData; 99 100 #define SPGIST_MAGIC_NUMBER (0xBA0BABEE) 101 102 #define SpGistPageGetMeta(p) \ 103 ((SpGistMetaPageData *) PageGetContents(p)) 104 105 /* 106 * Private state of index AM. SpGistState is common to both insert and 107 * search code; SpGistScanOpaque is for searches only. 108 */ 109 110 /* Per-datatype info needed in SpGistState */ 111 typedef struct SpGistTypeDesc 112 { 113 Oid type; 114 bool attbyval; 115 int16 attlen; 116 } SpGistTypeDesc; 117 118 typedef struct SpGistState 119 { 120 spgConfigOut config; /* filled in by opclass config method */ 121 122 SpGistTypeDesc attType; /* type of input data and leaf values */ 123 SpGistTypeDesc attPrefixType; /* type of inner-tuple prefix values */ 124 SpGistTypeDesc attLabelType; /* type of node label values */ 125 126 char *deadTupleStorage; /* workspace for spgFormDeadTuple */ 127 128 TransactionId myXid; /* XID to use when creating a redirect tuple */ 129 bool isBuild; /* true if doing index build */ 130 } SpGistState; 131 132 /* 133 * Private state of an index scan 134 */ 135 typedef struct SpGistScanOpaqueData 136 { 137 SpGistState state; /* see above */ 138 MemoryContext tempCxt; /* short-lived memory context */ 139 MemoryContext traversalCxt; /* memory context for traversalValues */ 140 141 /* Control flags showing whether to search nulls and/or non-nulls */ 142 bool searchNulls; /* scan matches (all) null entries */ 143 bool searchNonNulls; /* scan matches (some) non-null entries */ 144 145 /* Index quals to be passed to opclass (null-related quals removed) */ 146 int numberOfKeys; /* number of index qualifier conditions */ 147 ScanKey keyData; /* array of index qualifier descriptors */ 148 149 /* Stack of yet-to-be-visited pages */ 150 List *scanStack; /* List of ScanStackEntrys */ 151 152 /* These fields are only used in amgetbitmap scans: */ 153 TIDBitmap *tbm; /* bitmap being filled */ 154 int64 ntids; /* number of TIDs passed to bitmap */ 155 156 /* These fields are only used in amgettuple scans: */ 157 bool want_itup; /* are we reconstructing tuples? */ 158 TupleDesc indexTupDesc; /* if so, tuple descriptor for them */ 159 int nPtrs; /* number of TIDs found on current page */ 160 int iPtr; /* index for scanning through same */ 161 ItemPointerData heapPtrs[MaxIndexTuplesPerPage]; /* TIDs from cur page */ 162 bool recheck[MaxIndexTuplesPerPage]; /* their recheck flags */ 163 HeapTuple reconTups[MaxIndexTuplesPerPage]; /* reconstructed tuples */ 164 165 /* 166 * Note: using MaxIndexTuplesPerPage above is a bit hokey since 167 * SpGistLeafTuples aren't exactly IndexTuples; however, they are larger, 168 * so this is safe. 169 */ 170 } SpGistScanOpaqueData; 171 172 typedef SpGistScanOpaqueData *SpGistScanOpaque; 173 174 /* 175 * This struct is what we actually keep in index->rd_amcache. It includes 176 * static configuration information as well as the lastUsedPages cache. 177 */ 178 typedef struct SpGistCache 179 { 180 spgConfigOut config; /* filled in by opclass config method */ 181 182 SpGistTypeDesc attType; /* type of input data and leaf values */ 183 SpGistTypeDesc attPrefixType; /* type of inner-tuple prefix values */ 184 SpGistTypeDesc attLabelType; /* type of node label values */ 185 186 SpGistLUPCache lastUsedPages; /* local storage of last-used info */ 187 } SpGistCache; 188 189 190 /* 191 * SPGiST tuple types. Note: inner, leaf, and dead tuple structs 192 * must have the same tupstate field in the same position! Real inner and 193 * leaf tuples always have tupstate = LIVE; if the state is something else, 194 * use the SpGistDeadTuple struct to inspect the tuple. 195 */ 196 197 /* values of tupstate (see README for more info) */ 198 #define SPGIST_LIVE 0 /* normal live tuple (either inner or leaf) */ 199 #define SPGIST_REDIRECT 1 /* temporary redirection placeholder */ 200 #define SPGIST_DEAD 2 /* dead, cannot be removed because of links */ 201 #define SPGIST_PLACEHOLDER 3 /* placeholder, used to preserve offsets */ 202 203 /* 204 * SPGiST inner tuple: list of "nodes" that subdivide a set of tuples 205 * 206 * Inner tuple layout: 207 * header/optional prefix/array of nodes, which are SpGistNodeTuples 208 * 209 * size and prefixSize must be multiples of MAXALIGN 210 */ 211 typedef struct SpGistInnerTupleData 212 { 213 unsigned int tupstate:2, /* LIVE/REDIRECT/DEAD/PLACEHOLDER */ 214 allTheSame:1, /* all nodes in tuple are equivalent */ 215 nNodes:13, /* number of nodes within inner tuple */ 216 prefixSize:16; /* size of prefix, or 0 if none */ 217 uint16 size; /* total size of inner tuple */ 218 /* On most machines there will be a couple of wasted bytes here */ 219 /* prefix datum follows, then nodes */ 220 } SpGistInnerTupleData; 221 222 typedef SpGistInnerTupleData *SpGistInnerTuple; 223 224 /* these must match largest values that fit in bit fields declared above */ 225 #define SGITMAXNNODES 0x1FFF 226 #define SGITMAXPREFIXSIZE 0xFFFF 227 #define SGITMAXSIZE 0xFFFF 228 229 #define SGITHDRSZ MAXALIGN(sizeof(SpGistInnerTupleData)) 230 #define _SGITDATA(x) (((char *) (x)) + SGITHDRSZ) 231 #define SGITDATAPTR(x) ((x)->prefixSize ? _SGITDATA(x) : NULL) 232 #define SGITDATUM(x, s) ((x)->prefixSize ? \ 233 ((s)->attPrefixType.attbyval ? \ 234 *(Datum *) _SGITDATA(x) : \ 235 PointerGetDatum(_SGITDATA(x))) \ 236 : (Datum) 0) 237 #define SGITNODEPTR(x) ((SpGistNodeTuple) (_SGITDATA(x) + (x)->prefixSize)) 238 239 /* Macro for iterating through the nodes of an inner tuple */ 240 #define SGITITERATE(x, i, nt) \ 241 for ((i) = 0, (nt) = SGITNODEPTR(x); \ 242 (i) < (x)->nNodes; \ 243 (i)++, (nt) = (SpGistNodeTuple) (((char *) (nt)) + IndexTupleSize(nt))) 244 245 /* 246 * SPGiST node tuple: one node within an inner tuple 247 * 248 * Node tuples use the same header as ordinary Postgres IndexTuples, but 249 * we do not use a null bitmap, because we know there is only one column 250 * so the INDEX_NULL_MASK bit suffices. Also, pass-by-value datums are 251 * stored as a full Datum, the same convention as for inner tuple prefixes 252 * and leaf tuple datums. 253 */ 254 255 typedef IndexTupleData SpGistNodeTupleData; 256 257 typedef SpGistNodeTupleData *SpGistNodeTuple; 258 259 #define SGNTHDRSZ MAXALIGN(sizeof(SpGistNodeTupleData)) 260 #define SGNTDATAPTR(x) (((char *) (x)) + SGNTHDRSZ) 261 #define SGNTDATUM(x, s) ((s)->attLabelType.attbyval ? \ 262 *(Datum *) SGNTDATAPTR(x) : \ 263 PointerGetDatum(SGNTDATAPTR(x))) 264 265 /* 266 * SPGiST leaf tuple: carries a datum and a heap tuple TID 267 * 268 * In the simplest case, the datum is the same as the indexed value; but 269 * it could also be a suffix or some other sort of delta that permits 270 * reconstruction given knowledge of the prefix path traversed to get here. 271 * 272 * The size field is wider than could possibly be needed for an on-disk leaf 273 * tuple, but this allows us to form leaf tuples even when the datum is too 274 * wide to be stored immediately, and it costs nothing because of alignment 275 * considerations. 276 * 277 * Normally, nextOffset links to the next tuple belonging to the same parent 278 * node (which must be on the same page). But when the root page is a leaf 279 * page, we don't chain its tuples, so nextOffset is always 0 on the root. 280 * 281 * size must be a multiple of MAXALIGN; also, it must be at least SGDTSIZE 282 * so that the tuple can be converted to REDIRECT status later. (This 283 * restriction only adds bytes for the null-datum case, otherwise alignment 284 * restrictions force it anyway.) 285 * 286 * In a leaf tuple for a NULL indexed value, there's no useful datum value; 287 * however, the SGDTSIZE limit ensures that's there's a Datum word there 288 * anyway, so SGLTDATUM can be applied safely as long as you don't do 289 * anything with the result. 290 */ 291 typedef struct SpGistLeafTupleData 292 { 293 unsigned int tupstate:2, /* LIVE/REDIRECT/DEAD/PLACEHOLDER */ 294 size:30; /* large enough for any palloc'able value */ 295 OffsetNumber nextOffset; /* next tuple in chain, or InvalidOffset */ 296 ItemPointerData heapPtr; /* TID of represented heap tuple */ 297 /* leaf datum follows */ 298 } SpGistLeafTupleData; 299 300 typedef SpGistLeafTupleData *SpGistLeafTuple; 301 302 #define SGLTHDRSZ MAXALIGN(sizeof(SpGistLeafTupleData)) 303 #define SGLTDATAPTR(x) (((char *) (x)) + SGLTHDRSZ) 304 #define SGLTDATUM(x, s) ((s)->attType.attbyval ? \ 305 *(Datum *) SGLTDATAPTR(x) : \ 306 PointerGetDatum(SGLTDATAPTR(x))) 307 308 /* 309 * SPGiST dead tuple: declaration for examining non-live tuples 310 * 311 * The tupstate field of this struct must match those of regular inner and 312 * leaf tuples, and its size field must match a leaf tuple's. 313 * Also, the pointer field must be in the same place as a leaf tuple's heapPtr 314 * field, to satisfy some Asserts that we make when replacing a leaf tuple 315 * with a dead tuple. 316 * We don't use nextOffset, but it's needed to align the pointer field. 317 * pointer and xid are only valid when tupstate = REDIRECT. 318 */ 319 typedef struct SpGistDeadTupleData 320 { 321 unsigned int tupstate:2, /* LIVE/REDIRECT/DEAD/PLACEHOLDER */ 322 size:30; 323 OffsetNumber nextOffset; /* not used in dead tuples */ 324 ItemPointerData pointer; /* redirection inside index */ 325 TransactionId xid; /* ID of xact that inserted this tuple */ 326 } SpGistDeadTupleData; 327 328 typedef SpGistDeadTupleData *SpGistDeadTuple; 329 330 #define SGDTSIZE MAXALIGN(sizeof(SpGistDeadTupleData)) 331 332 /* 333 * Macros for doing free-space calculations. Note that when adding up the 334 * space needed for tuples, we always consider each tuple to need the tuple's 335 * size plus sizeof(ItemIdData) (for the line pointer). This works correctly 336 * so long as tuple sizes are always maxaligned. 337 */ 338 339 /* Page capacity after allowing for fixed header and special space */ 340 #define SPGIST_PAGE_CAPACITY \ 341 MAXALIGN_DOWN(BLCKSZ - \ 342 SizeOfPageHeaderData - \ 343 MAXALIGN(sizeof(SpGistPageOpaqueData))) 344 345 /* 346 * Compute free space on page, assuming that up to n placeholders can be 347 * recycled if present (n should be the number of tuples to be inserted) 348 */ 349 #define SpGistPageGetFreeSpace(p, n) \ 350 (PageGetExactFreeSpace(p) + \ 351 Min(SpGistPageGetOpaque(p)->nPlaceholder, n) * \ 352 (SGDTSIZE + sizeof(ItemIdData))) 353 354 /* 355 * XLOG stuff 356 */ 357 358 #define STORE_STATE(s, d) \ 359 do { \ 360 (d).myXid = (s)->myXid; \ 361 (d).isBuild = (s)->isBuild; \ 362 } while(0) 363 364 /* 365 * The "flags" argument for SpGistGetBuffer should be either GBUF_LEAF to 366 * get a leaf page, or GBUF_INNER_PARITY(blockNumber) to get an inner 367 * page in the same triple-parity group as the specified block number. 368 * (Typically, this should be GBUF_INNER_PARITY(parentBlockNumber + 1) 369 * to follow the rule described in spgist/README.) 370 * In addition, GBUF_NULLS can be OR'd in to get a page for storage of 371 * null-valued tuples. 372 * 373 * Note: these flag values are used as indexes into lastUsedPages. 374 */ 375 #define GBUF_LEAF 0x03 376 #define GBUF_INNER_PARITY(x) ((x) % 3) 377 #define GBUF_NULLS 0x04 378 379 #define GBUF_PARITY_MASK 0x03 380 #define GBUF_REQ_LEAF(flags) (((flags) & GBUF_PARITY_MASK) == GBUF_LEAF) 381 #define GBUF_REQ_NULLS(flags) ((flags) & GBUF_NULLS) 382 383 /* spgutils.c */ 384 extern SpGistCache *spgGetCache(Relation index); 385 extern void initSpGistState(SpGistState *state, Relation index); 386 extern Buffer SpGistNewBuffer(Relation index); 387 extern void SpGistUpdateMetaPage(Relation index); 388 extern Buffer SpGistGetBuffer(Relation index, int flags, 389 int needSpace, bool *isNew); 390 extern void SpGistSetLastUsedPage(Relation index, Buffer buffer); 391 extern void SpGistInitPage(Page page, uint16 f); 392 extern void SpGistInitBuffer(Buffer b, uint16 f); 393 extern void SpGistInitMetapage(Page page); 394 extern unsigned int SpGistGetTypeSize(SpGistTypeDesc *att, Datum datum); 395 extern SpGistLeafTuple spgFormLeafTuple(SpGistState *state, 396 ItemPointer heapPtr, 397 Datum datum, bool isnull); 398 extern SpGistNodeTuple spgFormNodeTuple(SpGistState *state, 399 Datum label, bool isnull); 400 extern SpGistInnerTuple spgFormInnerTuple(SpGistState *state, 401 bool hasPrefix, Datum prefix, 402 int nNodes, SpGistNodeTuple *nodes); 403 extern SpGistDeadTuple spgFormDeadTuple(SpGistState *state, int tupstate, 404 BlockNumber blkno, OffsetNumber offnum); 405 extern Datum *spgExtractNodeLabels(SpGistState *state, 406 SpGistInnerTuple innerTuple); 407 extern OffsetNumber SpGistPageAddNewItem(SpGistState *state, Page page, 408 Item item, Size size, 409 OffsetNumber *startOffset, 410 bool errorOK); 411 412 /* spgdoinsert.c */ 413 extern void spgUpdateNodeLink(SpGistInnerTuple tup, int nodeN, 414 BlockNumber blkno, OffsetNumber offset); 415 extern void spgPageIndexMultiDelete(SpGistState *state, Page page, 416 OffsetNumber *itemnos, int nitems, 417 int firststate, int reststate, 418 BlockNumber blkno, OffsetNumber offnum); 419 extern bool spgdoinsert(Relation index, SpGistState *state, 420 ItemPointer heapPtr, Datum datum, bool isnull); 421 422 #endif /* SPGIST_PRIVATE_H */ 423