granicus.if.org Git - postgresql/blob - src/backend/access/index/indexam.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * indexam.c
   4  *        general index access method routines
   5  *
   6  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        $PostgreSQL: pgsql/src/backend/access/index/indexam.c,v 1.106 2008/04/12 23:14:21 tgl Exp $
  12  *
  13  * INTERFACE ROUTINES
  14  *              index_open              - open an index relation by relation OID
  15  *              index_close             - close an index relation
  16  *              index_beginscan - start a scan of an index with amgettuple
  17  *              index_beginscan_bitmap - start a scan of an index with amgetbitmap
  18  *              index_rescan    - restart a scan of an index
  19  *              index_endscan   - end a scan
  20  *              index_insert    - insert an index tuple into a relation
  21  *              index_markpos   - mark a scan position
  22  *              index_restrpos  - restore a scan position
  23  *              index_getnext   - get the next tuple from a scan
  24  *              index_getbitmap - get all tuples from a scan
  25  *              index_bulk_delete       - bulk deletion of index tuples
  26  *              index_vacuum_cleanup    - post-deletion cleanup of an index
  27  *              index_getprocid - get a support procedure OID
  28  *              index_getprocinfo - get a support procedure's lookup info
  29  *
  30  * NOTES
  31  *              This file contains the index_ routines which used
  32  *              to be a scattered collection of stuff in access/genam.
  33  *
  34  *
  35  * old comments
  36  *              Scans are implemented as follows:
  37  *
  38  *              `0' represents an invalid item pointer.
  39  *              `-' represents an unknown item pointer.
  40  *              `X' represents a known item pointers.
  41  *              `+' represents known or invalid item pointers.
  42  *              `*' represents any item pointers.
  43  *
  44  *              State is represented by a triple of these symbols in the order of
  45  *              previous, current, next.  Note that the case of reverse scans works
  46  *              identically.
  47  *
  48  *                              State   Result
  49  *              (1)             + + -   + 0 0                   (if the next item pointer is invalid)
  50  *              (2)                             + X -                   (otherwise)
  51  *              (3)             * 0 0   * 0 0                   (no change)
  52  *              (4)             + X 0   X 0 0                   (shift)
  53  *              (5)             * + X   + X -                   (shift, add unknown)
  54  *
  55  *              All other states cannot occur.
  56  *
  57  *              Note: It would be possible to cache the status of the previous and
  58  *                        next item pointer using the flags.
  59  *
  60  *-------------------------------------------------------------------------
  61  */
  62
  63 #include "postgres.h"
  64
  65 #include "access/genam.h"
  66 #include "access/heapam.h"
  67 #include "access/transam.h"
  68 #include "pgstat.h"
  69 #include "utils/relcache.h"
  70 #include "utils/snapmgr.h"
  71 #include "utils/tqual.h"
  72
  73
  74 /* ----------------------------------------------------------------
  75  *                                      macros used in index_ routines
  76  * ----------------------------------------------------------------
  77  */
  78 #define RELATION_CHECKS \
  79 ( \
  80         AssertMacro(RelationIsValid(indexRelation)), \
  81         AssertMacro(PointerIsValid(indexRelation->rd_am)) \
  82 )
  83
  84 #define SCAN_CHECKS \
  85 ( \
  86         AssertMacro(IndexScanIsValid(scan)), \
  87         AssertMacro(RelationIsValid(scan->indexRelation)), \
  88         AssertMacro(PointerIsValid(scan->indexRelation->rd_am)) \
  89 )
  90
  91 #define GET_REL_PROCEDURE(pname) \
  92 do { \
  93         procedure = &indexRelation->rd_aminfo->pname; \
  94         if (!OidIsValid(procedure->fn_oid)) \
  95         { \
  96                 RegProcedure    procOid = indexRelation->rd_am->pname; \
  97                 if (!RegProcedureIsValid(procOid)) \
  98                         elog(ERROR, "invalid %s regproc", CppAsString(pname)); \
  99                 fmgr_info_cxt(procOid, procedure, indexRelation->rd_indexcxt); \
 100         } \
 101 } while(0)
 102
 103 #define GET_SCAN_PROCEDURE(pname) \
 104 do { \
 105         procedure = &scan->indexRelation->rd_aminfo->pname; \
 106         if (!OidIsValid(procedure->fn_oid)) \
 107         { \
 108                 RegProcedure    procOid = scan->indexRelation->rd_am->pname; \
 109                 if (!RegProcedureIsValid(procOid)) \
 110                         elog(ERROR, "invalid %s regproc", CppAsString(pname)); \
 111                 fmgr_info_cxt(procOid, procedure, scan->indexRelation->rd_indexcxt); \
 112         } \
 113 } while(0)
 114
 115 static IndexScanDesc index_beginscan_internal(Relation indexRelation,
 116                                                  int nkeys, ScanKey key);
 117
 118
 119 /* ----------------------------------------------------------------
 120  *                                 index_ interface functions
 121  * ----------------------------------------------------------------
 122  */
 123
 124 /* ----------------
 125  *              index_open - open an index relation by relation OID
 126  *
 127  *              If lockmode is not "NoLock", the specified kind of lock is
 128  *              obtained on the index.  (Generally, NoLock should only be
 129  *              used if the caller knows it has some appropriate lock on the
 130  *              index already.)
 131  *
 132  *              An error is raised if the index does not exist.
 133  *
 134  *              This is a convenience routine adapted for indexscan use.
 135  *              Some callers may prefer to use relation_open directly.
 136  * ----------------
 137  */
 138 Relation
 139 index_open(Oid relationId, LOCKMODE lockmode)
 140 {
 141         Relation        r;
 142
 143         r = relation_open(relationId, lockmode);
 144
 145         if (r->rd_rel->relkind != RELKIND_INDEX)
 146                 ereport(ERROR,
 147                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 148                                  errmsg("\"%s\" is not an index",
 149                                                 RelationGetRelationName(r))));
 150
 151         return r;
 152 }
 153
 154 /* ----------------
 155  *              index_close - close an index relation
 156  *
 157  *              If lockmode is not "NoLock", we then release the specified lock.
 158  *
 159  *              Note that it is often sensible to hold a lock beyond index_close;
 160  *              in that case, the lock is released automatically at xact end.
 161  * ----------------
 162  */
 163 void
 164 index_close(Relation relation, LOCKMODE lockmode)
 165 {
 166         LockRelId       relid = relation->rd_lockInfo.lockRelId;
 167
 168         Assert(lockmode >= NoLock && lockmode < MAX_LOCKMODES);
 169
 170         /* The relcache does the real work... */
 171         RelationClose(relation);
 172
 173         if (lockmode != NoLock)
 174                 UnlockRelationId(&relid, lockmode);
 175 }
 176
 177 /* ----------------
 178  *              index_insert - insert an index tuple into a relation
 179  * ----------------
 180  */
 181 bool
 182 index_insert(Relation indexRelation,
 183                          Datum *values,
 184                          bool *isnull,
 185                          ItemPointer heap_t_ctid,
 186                          Relation heapRelation,
 187                          bool check_uniqueness)
 188 {
 189         FmgrInfo   *procedure;
 190
 191         RELATION_CHECKS;
 192         GET_REL_PROCEDURE(aminsert);
 193
 194         /*
 195          * have the am's insert proc do all the work.
 196          */
 197         return DatumGetBool(FunctionCall6(procedure,
 198                                                                           PointerGetDatum(indexRelation),
 199                                                                           PointerGetDatum(values),
 200                                                                           PointerGetDatum(isnull),
 201                                                                           PointerGetDatum(heap_t_ctid),
 202                                                                           PointerGetDatum(heapRelation),
 203                                                                           BoolGetDatum(check_uniqueness)));
 204 }
 205
 206 /*
 207  * index_beginscan - start a scan of an index with amgettuple
 208  *
 209  * Caller must be holding suitable locks on the heap and the index.
 210  */
 211 IndexScanDesc
 212 index_beginscan(Relation heapRelation,
 213                                 Relation indexRelation,
 214                                 Snapshot snapshot,
 215                                 int nkeys, ScanKey key)
 216 {
 217         IndexScanDesc scan;
 218
 219         scan = index_beginscan_internal(indexRelation, nkeys, key);
 220
 221         /*
 222          * Save additional parameters into the scandesc.  Everything else was set
 223          * up by RelationGetIndexScan.
 224          */
 225         scan->heapRelation = heapRelation;
 226         scan->xs_snapshot = snapshot;
 227
 228         return scan;
 229 }
 230
 231 /*
 232  * index_beginscan_bitmap - start a scan of an index with amgetbitmap
 233  *
 234  * As above, caller had better be holding some lock on the parent heap
 235  * relation, even though it's not explicitly mentioned here.
 236  */
 237 IndexScanDesc
 238 index_beginscan_bitmap(Relation indexRelation,
 239                                            Snapshot snapshot,
 240                                            int nkeys, ScanKey key)
 241 {
 242         IndexScanDesc scan;
 243
 244         scan = index_beginscan_internal(indexRelation, nkeys, key);
 245
 246         /*
 247          * Save additional parameters into the scandesc.  Everything else was set
 248          * up by RelationGetIndexScan.
 249          */
 250         scan->xs_snapshot = snapshot;
 251
 252         return scan;
 253 }
 254
 255 /*
 256  * index_beginscan_internal --- common code for index_beginscan variants
 257  */
 258 static IndexScanDesc
 259 index_beginscan_internal(Relation indexRelation,
 260                                                  int nkeys, ScanKey key)
 261 {
 262         IndexScanDesc scan;
 263         FmgrInfo   *procedure;
 264
 265         RELATION_CHECKS;
 266         GET_REL_PROCEDURE(ambeginscan);
 267
 268         /*
 269          * We hold a reference count to the relcache entry throughout the scan.
 270          */
 271         RelationIncrementReferenceCount(indexRelation);
 272
 273         /*
 274          * Tell the AM to open a scan.
 275          */
 276         scan = (IndexScanDesc)
 277                 DatumGetPointer(FunctionCall3(procedure,
 278                                                                           PointerGetDatum(indexRelation),
 279                                                                           Int32GetDatum(nkeys),
 280                                                                           PointerGetDatum(key)));
 281
 282         return scan;
 283 }
 284
 285 /* ----------------
 286  *              index_rescan  - (re)start a scan of an index
 287  *
 288  * The caller may specify a new set of scankeys (but the number of keys
 289  * cannot change).      To restart the scan without changing keys, pass NULL
 290  * for the key array.
 291  *
 292  * Note that this is also called when first starting an indexscan;
 293  * see RelationGetIndexScan.  Keys *must* be passed in that case,
 294  * unless scan->numberOfKeys is zero.
 295  * ----------------
 296  */
 297 void
 298 index_rescan(IndexScanDesc scan, ScanKey key)
 299 {
 300         FmgrInfo   *procedure;
 301
 302         SCAN_CHECKS;
 303         GET_SCAN_PROCEDURE(amrescan);
 304
 305         /* Release any held pin on a heap page */
 306         if (BufferIsValid(scan->xs_cbuf))
 307         {
 308                 ReleaseBuffer(scan->xs_cbuf);
 309                 scan->xs_cbuf = InvalidBuffer;
 310         }
 311
 312         scan->xs_next_hot = InvalidOffsetNumber;
 313
 314         scan->kill_prior_tuple = false;         /* for safety */
 315
 316         FunctionCall2(procedure,
 317                                   PointerGetDatum(scan),
 318                                   PointerGetDatum(key));
 319 }
 320
 321 /* ----------------
 322  *              index_endscan - end a scan
 323  * ----------------
 324  */
 325 void
 326 index_endscan(IndexScanDesc scan)
 327 {
 328         FmgrInfo   *procedure;
 329
 330         SCAN_CHECKS;
 331         GET_SCAN_PROCEDURE(amendscan);
 332
 333         /* Release any held pin on a heap page */
 334         if (BufferIsValid(scan->xs_cbuf))
 335         {
 336                 ReleaseBuffer(scan->xs_cbuf);
 337                 scan->xs_cbuf = InvalidBuffer;
 338         }
 339
 340         /* End the AM's scan */
 341         FunctionCall1(procedure, PointerGetDatum(scan));
 342
 343         /* Release index refcount acquired by index_beginscan */
 344         RelationDecrementReferenceCount(scan->indexRelation);
 345
 346         /* Release the scan data structure itself */
 347         IndexScanEnd(scan);
 348 }
 349
 350 /* ----------------
 351  *              index_markpos  - mark a scan position
 352  * ----------------
 353  */
 354 void
 355 index_markpos(IndexScanDesc scan)
 356 {
 357         FmgrInfo   *procedure;
 358
 359         SCAN_CHECKS;
 360         GET_SCAN_PROCEDURE(ammarkpos);
 361
 362         FunctionCall1(procedure, PointerGetDatum(scan));
 363 }
 364
 365 /* ----------------
 366  *              index_restrpos  - restore a scan position
 367  *
 368  * NOTE: this only restores the internal scan state of the index AM.
 369  * The current result tuple (scan->xs_ctup) doesn't change.  See comments
 370  * for ExecRestrPos().
 371  *
 372  * NOTE: in the presence of HOT chains, mark/restore only works correctly
 373  * if the scan's snapshot is MVCC-safe; that ensures that there's at most one
 374  * returnable tuple in each HOT chain, and so restoring the prior state at the
 375  * granularity of the index AM is sufficient.  Since the only current user
 376  * of mark/restore functionality is nodeMergejoin.c, this effectively means
 377  * that merge-join plans only work for MVCC snapshots.  This could be fixed
 378  * if necessary, but for now it seems unimportant.
 379  * ----------------
 380  */
 381 void
 382 index_restrpos(IndexScanDesc scan)
 383 {
 384         FmgrInfo   *procedure;
 385
 386         Assert(IsMVCCSnapshot(scan->xs_snapshot));
 387
 388         SCAN_CHECKS;
 389         GET_SCAN_PROCEDURE(amrestrpos);
 390
 391         scan->xs_next_hot = InvalidOffsetNumber;
 392
 393         scan->kill_prior_tuple = false;         /* for safety */
 394
 395         FunctionCall1(procedure, PointerGetDatum(scan));
 396 }
 397
 398 /* ----------------
 399  *              index_getnext - get the next heap tuple from a scan
 400  *
 401  * The result is the next heap tuple satisfying the scan keys and the
 402  * snapshot, or NULL if no more matching tuples exist.  On success,
 403  * the buffer containing the heap tuple is pinned (the pin will be dropped
 404  * at the next index_getnext or index_endscan).
 405  * ----------------
 406  */
 407 HeapTuple
 408 index_getnext(IndexScanDesc scan, ScanDirection direction)
 409 {
 410         HeapTuple       heapTuple = &scan->xs_ctup;
 411         ItemPointer tid = &heapTuple->t_self;
 412         FmgrInfo   *procedure;
 413
 414         SCAN_CHECKS;
 415         GET_SCAN_PROCEDURE(amgettuple);
 416
 417         /*
 418          * We always reset xs_hot_dead; if we are here then either we are just
 419          * starting the scan, or we previously returned a visible tuple, and in
 420          * either case it's inappropriate to kill the prior index entry.
 421          */
 422         scan->xs_hot_dead = false;
 423
 424         for (;;)
 425         {
 426                 OffsetNumber offnum;
 427                 bool            at_chain_start;
 428                 Page            dp;
 429
 430                 if (scan->xs_next_hot != InvalidOffsetNumber)
 431                 {
 432                         /*
 433                          * We are resuming scan of a HOT chain after having returned an
 434                          * earlier member.      Must still hold pin on current heap page.
 435                          */
 436                         Assert(BufferIsValid(scan->xs_cbuf));
 437                         Assert(ItemPointerGetBlockNumber(tid) ==
 438                                    BufferGetBlockNumber(scan->xs_cbuf));
 439                         Assert(TransactionIdIsValid(scan->xs_prev_xmax));
 440                         offnum = scan->xs_next_hot;
 441                         at_chain_start = false;
 442                         scan->xs_next_hot = InvalidOffsetNumber;
 443                 }
 444                 else
 445                 {
 446                         bool            found;
 447                         Buffer          prev_buf;
 448
 449                         /*
 450                          * If we scanned a whole HOT chain and found only dead tuples,
 451                          * tell index AM to kill its entry for that TID.
 452                          */
 453                         scan->kill_prior_tuple = scan->xs_hot_dead;
 454
 455                         /*
 456                          * The AM's gettuple proc finds the next index entry matching the
 457                          * scan keys, and puts the TID in xs_ctup.t_self (ie, *tid).
 458                          */
 459                         found = DatumGetBool(FunctionCall2(procedure,
 460                                                                                            PointerGetDatum(scan),
 461                                                                                            Int32GetDatum(direction)));
 462
 463                         /* Reset kill flag immediately for safety */
 464                         scan->kill_prior_tuple = false;
 465
 466                         /* If we're out of index entries, break out of outer loop */
 467                         if (!found)
 468                                 break;
 469
 470                         pgstat_count_index_tuples(scan->indexRelation, 1);
 471
 472                         /* Switch to correct buffer if we don't have it already */
 473                         prev_buf = scan->xs_cbuf;
 474                         scan->xs_cbuf = ReleaseAndReadBuffer(scan->xs_cbuf,
 475                                                                                                  scan->heapRelation,
 476                                                                                          ItemPointerGetBlockNumber(tid));
 477
 478                         /*
 479                          * Prune page, but only if we weren't already on this page
 480                          */
 481                         if (prev_buf != scan->xs_cbuf)
 482                                 heap_page_prune_opt(scan->heapRelation, scan->xs_cbuf,
 483                                                                         RecentGlobalXmin);
 484
 485                         /* Prepare to scan HOT chain starting at index-referenced offnum */
 486                         offnum = ItemPointerGetOffsetNumber(tid);
 487                         at_chain_start = true;
 488
 489                         /* We don't know what the first tuple's xmin should be */
 490                         scan->xs_prev_xmax = InvalidTransactionId;
 491
 492                         /* Initialize flag to detect if all entries are dead */
 493                         scan->xs_hot_dead = true;
 494                 }
 495
 496                 /* Obtain share-lock on the buffer so we can examine visibility */
 497                 LockBuffer(scan->xs_cbuf, BUFFER_LOCK_SHARE);
 498
 499                 dp = (Page) BufferGetPage(scan->xs_cbuf);
 500
 501                 /* Scan through possible multiple members of HOT-chain */
 502                 for (;;)
 503                 {
 504                         ItemId          lp;
 505                         ItemPointer ctid;
 506
 507                         /* check for bogus TID */
 508                         if (offnum < FirstOffsetNumber ||
 509                                 offnum > PageGetMaxOffsetNumber(dp))
 510                                 break;
 511
 512                         lp = PageGetItemId(dp, offnum);
 513
 514                         /* check for unused, dead, or redirected items */
 515                         if (!ItemIdIsNormal(lp))
 516                         {
 517                                 /* We should only see a redirect at start of chain */
 518                                 if (ItemIdIsRedirected(lp) && at_chain_start)
 519                                 {
 520                                         /* Follow the redirect */
 521                                         offnum = ItemIdGetRedirect(lp);
 522                                         at_chain_start = false;
 523                                         continue;
 524                                 }
 525                                 /* else must be end of chain */
 526                                 break;
 527                         }
 528
 529                         /*
 530                          * We must initialize all of *heapTuple (ie, scan->xs_ctup) since
 531                          * it is returned to the executor on success.
 532                          */
 533                         heapTuple->t_data = (HeapTupleHeader) PageGetItem(dp, lp);
 534                         heapTuple->t_len = ItemIdGetLength(lp);
 535                         ItemPointerSetOffsetNumber(tid, offnum);
 536                         heapTuple->t_tableOid = RelationGetRelid(scan->heapRelation);
 537                         ctid = &heapTuple->t_data->t_ctid;
 538
 539                         /*
 540                          * Shouldn't see a HEAP_ONLY tuple at chain start.  (This test
 541                          * should be unnecessary, since the chain root can't be removed
 542                          * while we have pin on the index entry, but let's make it
 543                          * anyway.)
 544                          */
 545                         if (at_chain_start && HeapTupleIsHeapOnly(heapTuple))
 546                                 break;
 547
 548                         /*
 549                          * The xmin should match the previous xmax value, else chain is
 550                          * broken.      (Note: this test is not optional because it protects
 551                          * us against the case where the prior chain member's xmax aborted
 552                          * since we looked at it.)
 553                          */
 554                         if (TransactionIdIsValid(scan->xs_prev_xmax) &&
 555                                 !TransactionIdEquals(scan->xs_prev_xmax,
 556                                                                   HeapTupleHeaderGetXmin(heapTuple->t_data)))
 557                                 break;
 558
 559                         /* If it's visible per the snapshot, we must return it */
 560                         if (HeapTupleSatisfiesVisibility(heapTuple, scan->xs_snapshot,
 561                                                                                          scan->xs_cbuf))
 562                         {
 563                                 /*
 564                                  * If the snapshot is MVCC, we know that it could accept at
 565                                  * most one member of the HOT chain, so we can skip examining
 566                                  * any more members.  Otherwise, check for continuation of the
 567                                  * HOT-chain, and set state for next time.
 568                                  */
 569                                 if (IsMVCCSnapshot(scan->xs_snapshot))
 570                                         scan->xs_next_hot = InvalidOffsetNumber;
 571                                 else if (HeapTupleIsHotUpdated(heapTuple))
 572                                 {
 573                                         Assert(ItemPointerGetBlockNumber(ctid) ==
 574                                                    ItemPointerGetBlockNumber(tid));
 575                                         scan->xs_next_hot = ItemPointerGetOffsetNumber(ctid);
 576                                         scan->xs_prev_xmax = HeapTupleHeaderGetXmax(heapTuple->t_data);
 577                                 }
 578                                 else
 579                                         scan->xs_next_hot = InvalidOffsetNumber;
 580
 581                                 LockBuffer(scan->xs_cbuf, BUFFER_LOCK_UNLOCK);
 582
 583                                 pgstat_count_heap_fetch(scan->indexRelation);
 584
 585                                 return heapTuple;
 586                         }
 587
 588                         /*
 589                          * If we can't see it, maybe no one else can either.  Check to see
 590                          * if the tuple is dead to all transactions.  If we find that all
 591                          * the tuples in the HOT chain are dead, we'll signal the index AM
 592                          * to not return that TID on future indexscans.
 593                          */
 594                         if (scan->xs_hot_dead &&
 595                                 HeapTupleSatisfiesVacuum(heapTuple->t_data, RecentGlobalXmin,
 596                                                                                  scan->xs_cbuf) != HEAPTUPLE_DEAD)
 597                                 scan->xs_hot_dead = false;
 598
 599                         /*
 600                          * Check to see if HOT chain continues past this tuple; if so
 601                          * fetch the next offnum (we don't bother storing it into
 602                          * xs_next_hot, but must store xs_prev_xmax), and loop around.
 603                          */
 604                         if (HeapTupleIsHotUpdated(heapTuple))
 605                         {
 606                                 Assert(ItemPointerGetBlockNumber(ctid) ==
 607                                            ItemPointerGetBlockNumber(tid));
 608                                 offnum = ItemPointerGetOffsetNumber(ctid);
 609                                 at_chain_start = false;
 610                                 scan->xs_prev_xmax = HeapTupleHeaderGetXmax(heapTuple->t_data);
 611                         }
 612                         else
 613                                 break;                  /* end of chain */
 614                 }                                               /* loop over a single HOT chain */
 615
 616                 LockBuffer(scan->xs_cbuf, BUFFER_LOCK_UNLOCK);
 617
 618                 /* Loop around to ask index AM for another TID */
 619                 scan->xs_next_hot = InvalidOffsetNumber;
 620         }
 621
 622         /* Release any held pin on a heap page */
 623         if (BufferIsValid(scan->xs_cbuf))
 624         {
 625                 ReleaseBuffer(scan->xs_cbuf);
 626                 scan->xs_cbuf = InvalidBuffer;
 627         }
 628
 629         return NULL;                            /* failure exit */
 630 }
 631
 632 /* ----------------
 633  *              index_getbitmap - get all tuples at once from an index scan
 634  *
 635  * Adds the TIDs of all heap tuples satisfying the scan keys to a bitmap.
 636  * Since there's no interlock between the index scan and the eventual heap
 637  * access, this is only safe to use with MVCC-based snapshots: the heap
 638  * item slot could have been replaced by a newer tuple by the time we get
 639  * to it.
 640  *
 641  * Returns the number of matching tuples found.
 642  * ----------------
 643  */
 644 int64
 645 index_getbitmap(IndexScanDesc scan, TIDBitmap *bitmap)
 646 {
 647         FmgrInfo   *procedure;
 648         int64           ntids;
 649
 650         SCAN_CHECKS;
 651         GET_SCAN_PROCEDURE(amgetbitmap);
 652
 653         /* just make sure this is false... */
 654         scan->kill_prior_tuple = false;
 655
 656         /*
 657          * have the am's getbitmap proc do all the work.
 658          */
 659         ntids = DatumGetInt64(FunctionCall2(procedure,
 660                                                                                 PointerGetDatum(scan),
 661                                                                                 PointerGetDatum(bitmap)));
 662
 663         pgstat_count_index_tuples(scan->indexRelation, ntids);
 664
 665         return ntids;
 666 }
 667
 668 /* ----------------
 669  *              index_bulk_delete - do mass deletion of index entries
 670  *
 671  *              callback routine tells whether a given main-heap tuple is
 672  *              to be deleted
 673  *
 674  *              return value is an optional palloc'd struct of statistics
 675  * ----------------
 676  */
 677 IndexBulkDeleteResult *
 678 index_bulk_delete(IndexVacuumInfo *info,
 679                                   IndexBulkDeleteResult *stats,
 680                                   IndexBulkDeleteCallback callback,
 681                                   void *callback_state)
 682 {
 683         Relation        indexRelation = info->index;
 684         FmgrInfo   *procedure;
 685         IndexBulkDeleteResult *result;
 686
 687         RELATION_CHECKS;
 688         GET_REL_PROCEDURE(ambulkdelete);
 689
 690         result = (IndexBulkDeleteResult *)
 691                 DatumGetPointer(FunctionCall4(procedure,
 692                                                                           PointerGetDatum(info),
 693                                                                           PointerGetDatum(stats),
 694                                                                           PointerGetDatum((Pointer) callback),
 695                                                                           PointerGetDatum(callback_state)));
 696
 697         return result;
 698 }
 699
 700 /* ----------------
 701  *              index_vacuum_cleanup - do post-deletion cleanup of an index
 702  *
 703  *              return value is an optional palloc'd struct of statistics
 704  * ----------------
 705  */
 706 IndexBulkDeleteResult *
 707 index_vacuum_cleanup(IndexVacuumInfo *info,
 708                                          IndexBulkDeleteResult *stats)
 709 {
 710         Relation        indexRelation = info->index;
 711         FmgrInfo   *procedure;
 712         IndexBulkDeleteResult *result;
 713
 714         RELATION_CHECKS;
 715         GET_REL_PROCEDURE(amvacuumcleanup);
 716
 717         result = (IndexBulkDeleteResult *)
 718                 DatumGetPointer(FunctionCall2(procedure,
 719                                                                           PointerGetDatum(info),
 720                                                                           PointerGetDatum(stats)));
 721
 722         return result;
 723 }
 724
 725 /* ----------------
 726  *              index_getprocid
 727  *
 728  *              Index access methods typically require support routines that are
 729  *              not directly the implementation of any WHERE-clause query operator
 730  *              and so cannot be kept in pg_amop.  Instead, such routines are kept
 731  *              in pg_amproc.  These registered procedure OIDs are assigned numbers
 732  *              according to a convention established by the access method.
 733  *              The general index code doesn't know anything about the routines
 734  *              involved; it just builds an ordered list of them for
 735  *              each attribute on which an index is defined.
 736  *
 737  *              As of Postgres 8.3, support routines within an operator family
 738  *              are further subdivided by the "left type" and "right type" of the
 739  *              query operator(s) that they support.  The "default" functions for a
 740  *              particular indexed attribute are those with both types equal to
 741  *              the index opclass' opcintype (note that this is subtly different
 742  *              from the indexed attribute's own type: it may be a binary-compatible
 743  *              type instead).  Only the default functions are stored in relcache
 744  *              entries --- access methods can use the syscache to look up non-default
 745  *              functions.
 746  *
 747  *              This routine returns the requested default procedure OID for a
 748  *              particular indexed attribute.
 749  * ----------------
 750  */
 751 RegProcedure
 752 index_getprocid(Relation irel,
 753                                 AttrNumber attnum,
 754                                 uint16 procnum)
 755 {
 756         RegProcedure *loc;
 757         int                     nproc;
 758         int                     procindex;
 759
 760         nproc = irel->rd_am->amsupport;
 761
 762         Assert(procnum > 0 && procnum <= (uint16) nproc);
 763
 764         procindex = (nproc * (attnum - 1)) + (procnum - 1);
 765
 766         loc = irel->rd_support;
 767
 768         Assert(loc != NULL);
 769
 770         return loc[procindex];
 771 }
 772
 773 /* ----------------
 774  *              index_getprocinfo
 775  *
 776  *              This routine allows index AMs to keep fmgr lookup info for
 777  *              support procs in the relcache.  As above, only the "default"
 778  *              functions for any particular indexed attribute are cached.
 779  *
 780  * Note: the return value points into cached data that will be lost during
 781  * any relcache rebuild!  Therefore, either use the callinfo right away,
 782  * or save it only after having acquired some type of lock on the index rel.
 783  * ----------------
 784  */
 785 FmgrInfo *
 786 index_getprocinfo(Relation irel,
 787                                   AttrNumber attnum,
 788                                   uint16 procnum)
 789 {
 790         FmgrInfo   *locinfo;
 791         int                     nproc;
 792         int                     procindex;
 793
 794         nproc = irel->rd_am->amsupport;
 795
 796         Assert(procnum > 0 && procnum <= (uint16) nproc);
 797
 798         procindex = (nproc * (attnum - 1)) + (procnum - 1);
 799
 800         locinfo = irel->rd_supportinfo;
 801
 802         Assert(locinfo != NULL);
 803
 804         locinfo += procindex;
 805
 806         /* Initialize the lookup info if first time through */
 807         if (locinfo->fn_oid == InvalidOid)
 808         {
 809                 RegProcedure *loc = irel->rd_support;
 810                 RegProcedure procId;
 811
 812                 Assert(loc != NULL);
 813
 814                 procId = loc[procindex];
 815
 816                 /*
 817                  * Complain if function was not found during IndexSupportInitialize.
 818                  * This should not happen unless the system tables contain bogus
 819                  * entries for the index opclass.  (If an AM wants to allow a support
 820                  * function to be optional, it can use index_getprocid.)
 821                  */
 822                 if (!RegProcedureIsValid(procId))
 823                         elog(ERROR, "missing support function %d for attribute %d of index \"%s\"",
 824                                  procnum, attnum, RelationGetRelationName(irel));
 825
 826                 fmgr_info_cxt(procId, locinfo, irel->rd_indexcxt);
 827         }
 828
 829         return locinfo;
 830 }