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) 1996-2005, 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 1.84 2005/06/27 12:45:22 teodor Exp $
  12  *
  13  * INTERFACE ROUTINES
  14  *              index_open              - open an index relation by relation OID
  15  *              index_openrv    - open an index relation specified by a RangeVar
  16  *              index_close             - close an index relation
  17  *              index_beginscan - start a scan of an index with amgettuple
  18  *              index_beginscan_multi - start a scan of an index with amgetmulti
  19  *              index_rescan    - restart a scan of an index
  20  *              index_endscan   - end a scan
  21  *              index_insert    - insert an index tuple into a relation
  22  *              index_markpos   - mark a scan position
  23  *              index_restrpos  - restore a scan position
  24  *              index_getnext   - get the next tuple from a scan
  25  *              index_getmulti  - get multiple tuples from a scan
  26  *              index_bulk_delete       - bulk deletion of index tuples
  27  *              index_vacuum_cleanup    - post-deletion cleanup of an index
  28  *              index_getprocid - get a support procedure OID
  29  *              index_getprocinfo - get a support procedure's lookup info
  30  *
  31  * NOTES
  32  *              This file contains the index_ routines which used
  33  *              to be a scattered collection of stuff in access/genam.
  34  *
  35  *
  36  * old comments
  37  *              Scans are implemented as follows:
  38  *
  39  *              `0' represents an invalid item pointer.
  40  *              `-' represents an unknown item pointer.
  41  *              `X' represents a known item pointers.
  42  *              `+' represents known or invalid item pointers.
  43  *              `*' represents any item pointers.
  44  *
  45  *              State is represented by a triple of these symbols in the order of
  46  *              previous, current, next.  Note that the case of reverse scans works
  47  *              identically.
  48  *
  49  *                              State   Result
  50  *              (1)             + + -   + 0 0                   (if the next item pointer is invalid)
  51  *              (2)                             + X -                   (otherwise)
  52  *              (3)             * 0 0   * 0 0                   (no change)
  53  *              (4)             + X 0   X 0 0                   (shift)
  54  *              (5)             * + X   + X -                   (shift, add unknown)
  55  *
  56  *              All other states cannot occur.
  57  *
  58  *              Note: It would be possible to cache the status of the previous and
  59  *                        next item pointer using the flags.
  60  *
  61  *-------------------------------------------------------------------------
  62  */
  63
  64 #include "postgres.h"
  65
  66 #include "access/genam.h"
  67 #include "access/heapam.h"
  68 #include "utils/relcache.h"
  69
  70 #include "pgstat.h"
  71
  72 /* ----------------------------------------------------------------
  73  *                                      macros used in index_ routines
  74  * ----------------------------------------------------------------
  75  */
  76 #define RELATION_CHECKS \
  77 ( \
  78         AssertMacro(RelationIsValid(indexRelation)), \
  79         AssertMacro(PointerIsValid(indexRelation->rd_am)) \
  80 )
  81
  82 #define SCAN_CHECKS \
  83 ( \
  84         AssertMacro(IndexScanIsValid(scan)), \
  85         AssertMacro(RelationIsValid(scan->indexRelation)), \
  86         AssertMacro(PointerIsValid(scan->indexRelation->rd_am)) \
  87 )
  88
  89 #define GET_REL_PROCEDURE(pname) \
  90 do { \
  91         procedure = &indexRelation->rd_aminfo->pname; \
  92         if (!OidIsValid(procedure->fn_oid)) \
  93         { \
  94                 RegProcedure    procOid = indexRelation->rd_am->pname; \
  95                 if (!RegProcedureIsValid(procOid)) \
  96                         elog(ERROR, "invalid %s regproc", CppAsString(pname)); \
  97                 fmgr_info_cxt(procOid, procedure, indexRelation->rd_indexcxt); \
  98         } \
  99 } while(0)
 100
 101 #define GET_SCAN_PROCEDURE(pname) \
 102 do { \
 103         procedure = &scan->indexRelation->rd_aminfo->pname; \
 104         if (!OidIsValid(procedure->fn_oid)) \
 105         { \
 106                 RegProcedure    procOid = scan->indexRelation->rd_am->pname; \
 107                 if (!RegProcedureIsValid(procOid)) \
 108                         elog(ERROR, "invalid %s regproc", CppAsString(pname)); \
 109                 fmgr_info_cxt(procOid, procedure, scan->indexRelation->rd_indexcxt); \
 110         } \
 111 } while(0)
 112
 113 static IndexScanDesc index_beginscan_internal(Relation indexRelation,
 114                                                                                           int nkeys, ScanKey key);
 115
 116
 117 /* ----------------------------------------------------------------
 118  *                                 index_ interface functions
 119  * ----------------------------------------------------------------
 120  */
 121
 122 /* ----------------
 123  *              index_open - open an index relation by relation OID
 124  *
 125  *              Note: we acquire no lock on the index.  A lock is not needed when
 126  *              simply examining the index reldesc; the index's schema information
 127  *              is considered to be protected by the lock that the caller had better
 128  *              be holding on the parent relation.  Some type of lock should be
 129  *              obtained on the index before physically accessing it, however.
 130  *              This is handled automatically for most uses by index_beginscan
 131  *              and index_endscan for scan cases, or by ExecOpenIndices and
 132  *              ExecCloseIndices for update cases.  Other callers will need to
 133  *              obtain their own locks.
 134  *
 135  *              This is a convenience routine adapted for indexscan use.
 136  *              Some callers may prefer to use relation_open directly.
 137  * ----------------
 138  */
 139 Relation
 140 index_open(Oid relationId)
 141 {
 142         Relation        r;
 143
 144         r = relation_open(relationId, NoLock);
 145
 146         if (r->rd_rel->relkind != RELKIND_INDEX)
 147                 ereport(ERROR,
 148                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 149                                  errmsg("\"%s\" is not an index",
 150                                                 RelationGetRelationName(r))));
 151
 152         pgstat_initstats(&r->pgstat_info, r);
 153
 154         return r;
 155 }
 156
 157 /* ----------------
 158  *              index_openrv - open an index relation specified
 159  *              by a RangeVar node
 160  *
 161  *              As above, but relation is specified by a RangeVar.
 162  * ----------------
 163  */
 164 Relation
 165 index_openrv(const RangeVar *relation)
 166 {
 167         Relation        r;
 168
 169         r = relation_openrv(relation, NoLock);
 170
 171         if (r->rd_rel->relkind != RELKIND_INDEX)
 172                 ereport(ERROR,
 173                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 174                                  errmsg("\"%s\" is not an index",
 175                                                 RelationGetRelationName(r))));
 176
 177         pgstat_initstats(&r->pgstat_info, r);
 178
 179         return r;
 180 }
 181
 182 /* ----------------
 183  *              index_close - close a index relation
 184  *
 185  *              presently the relcache routines do all the work we need
 186  *              to open/close index relations.
 187  * ----------------
 188  */
 189 void
 190 index_close(Relation relation)
 191 {
 192         RelationClose(relation);
 193 }
 194
 195 /* ----------------
 196  *              index_insert - insert an index tuple into a relation
 197  * ----------------
 198  */
 199 bool
 200 index_insert(Relation indexRelation,
 201                          Datum *values,
 202                          bool *isnull,
 203                          ItemPointer heap_t_ctid,
 204                          Relation heapRelation,
 205                          bool check_uniqueness)
 206 {
 207         FmgrInfo   *procedure;
 208
 209         RELATION_CHECKS;
 210         GET_REL_PROCEDURE(aminsert);
 211
 212         /*
 213          * have the am's insert proc do all the work.
 214          */
 215         return DatumGetBool(FunctionCall6(procedure,
 216                                                                           PointerGetDatum(indexRelation),
 217                                                                           PointerGetDatum(values),
 218                                                                           PointerGetDatum(isnull),
 219                                                                           PointerGetDatum(heap_t_ctid),
 220                                                                           PointerGetDatum(heapRelation),
 221                                                                           BoolGetDatum(check_uniqueness)));
 222 }
 223
 224 /*
 225  * index_beginscan - start a scan of an index with amgettuple
 226  *
 227  * Note: heapRelation may be NULL if there is no intention of calling
 228  * index_getnext on this scan; index_getnext_indexitem will not use the
 229  * heapRelation link (nor the snapshot).  However, the caller had better
 230  * be holding some kind of lock on the heap relation in any case, to ensure
 231  * no one deletes it (or the index) out from under us.
 232  */
 233 IndexScanDesc
 234 index_beginscan(Relation heapRelation,
 235                                 Relation indexRelation,
 236                                 Snapshot snapshot,
 237                                 int nkeys, ScanKey key)
 238 {
 239         IndexScanDesc scan;
 240
 241         scan = index_beginscan_internal(indexRelation, nkeys, key);
 242
 243         /*
 244          * Save additional parameters into the scandesc.  Everything else was
 245          * set up by RelationGetIndexScan.
 246          */
 247         scan->is_multiscan = false;
 248         scan->heapRelation = heapRelation;
 249         scan->xs_snapshot = snapshot;
 250
 251         return scan;
 252 }
 253
 254 /*
 255  * index_beginscan_multi - start a scan of an index with amgetmulti
 256  *
 257  * As above, caller had better be holding some lock on the parent heap
 258  * relation, even though it's not explicitly mentioned here.
 259  */
 260 IndexScanDesc
 261 index_beginscan_multi(Relation indexRelation,
 262                                           Snapshot snapshot,
 263                                           int nkeys, ScanKey key)
 264 {
 265         IndexScanDesc scan;
 266
 267         scan = index_beginscan_internal(indexRelation, nkeys, key);
 268
 269         /*
 270          * Save additional parameters into the scandesc.  Everything else was
 271          * set up by RelationGetIndexScan.
 272          */
 273         scan->is_multiscan = true;
 274         scan->xs_snapshot = snapshot;
 275
 276         return scan;
 277 }
 278
 279 /*
 280  * index_beginscan_internal --- common code for index_beginscan variants
 281  */
 282 static IndexScanDesc
 283 index_beginscan_internal(Relation indexRelation,
 284                                                  int nkeys, ScanKey key)
 285 {
 286         IndexScanDesc scan;
 287         FmgrInfo   *procedure;
 288
 289         RELATION_CHECKS;
 290
 291         RelationIncrementReferenceCount(indexRelation);
 292
 293         /*
 294          * Acquire AccessShareLock for the duration of the scan
 295          *
 296          * Note: we could get an SI inval message here and consequently have to
 297          * rebuild the relcache entry.  The refcount increment above ensures
 298          * that we will rebuild it and not just flush it...
 299          */
 300         LockRelation(indexRelation, AccessShareLock);
 301
 302         /*
 303          * LockRelation can clean rd_aminfo structure, so fill procedure
 304          * after LockRelation
 305          */
 306
 307         GET_REL_PROCEDURE(ambeginscan);
 308
 309         /*
 310          * Tell the AM to open a scan.
 311          */
 312         scan = (IndexScanDesc)
 313                 DatumGetPointer(FunctionCall3(procedure,
 314                                                                           PointerGetDatum(indexRelation),
 315                                                                           Int32GetDatum(nkeys),
 316                                                                           PointerGetDatum(key)));
 317
 318         return scan;
 319 }
 320
 321 /* ----------------
 322  *              index_rescan  - (re)start a scan of an index
 323  *
 324  * The caller may specify a new set of scankeys (but the number of keys
 325  * cannot change).      To restart the scan without changing keys, pass NULL
 326  * for the key array.
 327  *
 328  * Note that this is also called when first starting an indexscan;
 329  * see RelationGetIndexScan.  Keys *must* be passed in that case,
 330  * unless scan->numberOfKeys is zero.
 331  * ----------------
 332  */
 333 void
 334 index_rescan(IndexScanDesc scan, ScanKey key)
 335 {
 336         FmgrInfo   *procedure;
 337
 338         SCAN_CHECKS;
 339         GET_SCAN_PROCEDURE(amrescan);
 340
 341         /* Release any held pin on a heap page */
 342         if (BufferIsValid(scan->xs_cbuf))
 343         {
 344                 ReleaseBuffer(scan->xs_cbuf);
 345                 scan->xs_cbuf = InvalidBuffer;
 346         }
 347
 348         scan->kill_prior_tuple = false;         /* for safety */
 349         scan->keys_are_unique = false;          /* may be set by index AM */
 350         scan->got_tuple = false;
 351         scan->unique_tuple_pos = 0;
 352         scan->unique_tuple_mark = 0;
 353
 354         FunctionCall2(procedure,
 355                                   PointerGetDatum(scan),
 356                                   PointerGetDatum(key));
 357
 358         pgstat_reset_index_scan(&scan->xs_pgstat_info);
 359 }
 360
 361 /* ----------------
 362  *              index_endscan - end a scan
 363  * ----------------
 364  */
 365 void
 366 index_endscan(IndexScanDesc scan)
 367 {
 368         FmgrInfo   *procedure;
 369
 370         SCAN_CHECKS;
 371         GET_SCAN_PROCEDURE(amendscan);
 372
 373         /* Release any held pin on a heap page */
 374         if (BufferIsValid(scan->xs_cbuf))
 375         {
 376                 ReleaseBuffer(scan->xs_cbuf);
 377                 scan->xs_cbuf = InvalidBuffer;
 378         }
 379
 380         /* End the AM's scan */
 381         FunctionCall1(procedure, PointerGetDatum(scan));
 382
 383         /* Release index lock and refcount acquired by index_beginscan */
 384
 385         UnlockRelation(scan->indexRelation, AccessShareLock);
 386
 387         RelationDecrementReferenceCount(scan->indexRelation);
 388
 389         /* Release the scan data structure itself */
 390         IndexScanEnd(scan);
 391 }
 392
 393 /* ----------------
 394  *              index_markpos  - mark a scan position
 395  * ----------------
 396  */
 397 void
 398 index_markpos(IndexScanDesc scan)
 399 {
 400         FmgrInfo   *procedure;
 401
 402         SCAN_CHECKS;
 403         GET_SCAN_PROCEDURE(ammarkpos);
 404
 405         scan->unique_tuple_mark = scan->unique_tuple_pos;
 406
 407         FunctionCall1(procedure, PointerGetDatum(scan));
 408 }
 409
 410 /* ----------------
 411  *              index_restrpos  - restore a scan position
 412  *
 413  * NOTE: this only restores the internal scan state of the index AM.
 414  * The current result tuple (scan->xs_ctup) doesn't change.  See comments
 415  * for ExecRestrPos().
 416  * ----------------
 417  */
 418 void
 419 index_restrpos(IndexScanDesc scan)
 420 {
 421         FmgrInfo   *procedure;
 422
 423         SCAN_CHECKS;
 424         GET_SCAN_PROCEDURE(amrestrpos);
 425
 426         scan->kill_prior_tuple = false;         /* for safety */
 427
 428         /*
 429          * We do not reset got_tuple; so if the scan is actually being
 430          * short-circuited by index_getnext, the effective position
 431          * restoration is done by restoring unique_tuple_pos.
 432          */
 433         scan->unique_tuple_pos = scan->unique_tuple_mark;
 434
 435         FunctionCall1(procedure, PointerGetDatum(scan));
 436 }
 437
 438 /* ----------------
 439  *              index_getnext - get the next heap tuple from a scan
 440  *
 441  * The result is the next heap tuple satisfying the scan keys and the
 442  * snapshot, or NULL if no more matching tuples exist.  On success,
 443  * the buffer containing the heap tuple is pinned (the pin will be dropped
 444  * at the next index_getnext or index_endscan).  The index TID corresponding
 445  * to the heap tuple can be obtained if needed from scan->currentItemData.
 446  * ----------------
 447  */
 448 HeapTuple
 449 index_getnext(IndexScanDesc scan, ScanDirection direction)
 450 {
 451         HeapTuple       heapTuple = &scan->xs_ctup;
 452         FmgrInfo   *procedure;
 453
 454         SCAN_CHECKS;
 455         GET_SCAN_PROCEDURE(amgettuple);
 456
 457         /*
 458          * If we already got a tuple and it must be unique, there's no need to
 459          * make the index AM look through any additional tuples.  (This can
 460          * save a useful amount of work in scenarios where there are many dead
 461          * tuples due to heavy update activity.)
 462          *
 463          * To do this we must keep track of the logical scan position
 464          * (before/on/after tuple).  Also, we have to be sure to release scan
 465          * resources before returning NULL; if we fail to do so then a
 466          * multi-index scan can easily run the system out of free buffers.      We
 467          * can release index-level resources fairly cheaply by calling
 468          * index_rescan.  This means there are two persistent states as far as
 469          * the index AM is concerned: on-tuple and rescanned.  If we are
 470          * actually asked to re-fetch the single tuple, we have to go through
 471          * a fresh indexscan startup, which penalizes that (infrequent) case.
 472          */
 473         if (scan->keys_are_unique && scan->got_tuple)
 474         {
 475                 int                     new_tuple_pos = scan->unique_tuple_pos;
 476
 477                 if (ScanDirectionIsForward(direction))
 478                 {
 479                         if (new_tuple_pos <= 0)
 480                                 new_tuple_pos++;
 481                 }
 482                 else
 483                 {
 484                         if (new_tuple_pos >= 0)
 485                                 new_tuple_pos--;
 486                 }
 487                 if (new_tuple_pos == 0)
 488                 {
 489                         /*
 490                          * We are moving onto the unique tuple from having been off
 491                          * it. We just fall through and let the index AM do the work.
 492                          * Note we should get the right answer regardless of scan
 493                          * direction.
 494                          */
 495                         scan->unique_tuple_pos = 0; /* need to update position */
 496                 }
 497                 else
 498                 {
 499                         /*
 500                          * Moving off the tuple; must do amrescan to release
 501                          * index-level pins before we return NULL.      Since index_rescan
 502                          * will reset my state, must save and restore...
 503                          */
 504                         int                     unique_tuple_mark = scan->unique_tuple_mark;
 505
 506                         index_rescan(scan, NULL /* no change to key */ );
 507
 508                         scan->keys_are_unique = true;
 509                         scan->got_tuple = true;
 510                         scan->unique_tuple_pos = new_tuple_pos;
 511                         scan->unique_tuple_mark = unique_tuple_mark;
 512
 513                         return NULL;
 514                 }
 515         }
 516
 517         /* just make sure this is false... */
 518         scan->kill_prior_tuple = false;
 519
 520         for (;;)
 521         {
 522                 bool            found;
 523
 524                 pgstat_count_index_scan(&scan->xs_pgstat_info);
 525
 526                 /*
 527                  * The AM's gettuple proc finds the next tuple matching the scan
 528                  * keys.
 529                  */
 530                 found = DatumGetBool(FunctionCall2(procedure,
 531                                                                                    PointerGetDatum(scan),
 532                                                                                    Int32GetDatum(direction)));
 533
 534                 /* Reset kill flag immediately for safety */
 535                 scan->kill_prior_tuple = false;
 536
 537                 if (!found)
 538                 {
 539                         /* Release any held pin on a heap page */
 540                         if (BufferIsValid(scan->xs_cbuf))
 541                         {
 542                                 ReleaseBuffer(scan->xs_cbuf);
 543                                 scan->xs_cbuf = InvalidBuffer;
 544                         }
 545                         return NULL;            /* failure exit */
 546                 }
 547
 548                 /*
 549                  * Fetch the heap tuple and see if it matches the snapshot.
 550                  */
 551                 if (heap_release_fetch(scan->heapRelation, scan->xs_snapshot,
 552                                                            heapTuple, &scan->xs_cbuf, true,
 553                                                            &scan->xs_pgstat_info))
 554                         break;
 555
 556                 /* Skip if no undeleted tuple at this location */
 557                 if (heapTuple->t_data == NULL)
 558                         continue;
 559
 560                 /*
 561                  * If we can't see it, maybe no one else can either.  Check to see
 562                  * if the tuple is dead to all transactions.  If so, signal the
 563                  * index AM to not return it on future indexscans.
 564                  *
 565                  * We told heap_release_fetch to keep a pin on the buffer, so we can
 566                  * re-access the tuple here.  But we must re-lock the buffer first.
 567                  */
 568                 LockBuffer(scan->xs_cbuf, BUFFER_LOCK_SHARE);
 569
 570                 if (HeapTupleSatisfiesVacuum(heapTuple->t_data, RecentGlobalXmin,
 571                                                                          scan->xs_cbuf) == HEAPTUPLE_DEAD)
 572                         scan->kill_prior_tuple = true;
 573
 574                 LockBuffer(scan->xs_cbuf, BUFFER_LOCK_UNLOCK);
 575         }
 576
 577         /* Success exit */
 578         scan->got_tuple = true;
 579
 580         /*
 581          * If we just fetched a known-unique tuple, then subsequent calls will
 582          * go through the short-circuit code above.  unique_tuple_pos has been
 583          * initialized to 0, which is the correct state ("on row").
 584          */
 585
 586         pgstat_count_index_getnext(&scan->xs_pgstat_info);
 587
 588         return heapTuple;
 589 }
 590
 591 /* ----------------
 592  *              index_getnext_indexitem - get the next index tuple from a scan
 593  *
 594  * Finds the next index tuple satisfying the scan keys.  Note that the
 595  * corresponding heap tuple is not accessed, and thus no time qual (snapshot)
 596  * check is done, other than the index AM's internal check for killed tuples
 597  * (which most callers of this routine will probably want to suppress by
 598  * setting scan->ignore_killed_tuples = false).
 599  *
 600  * On success (TRUE return), the found index TID is in scan->currentItemData,
 601  * and its heap TID is in scan->xs_ctup.t_self.  scan->xs_cbuf is untouched.
 602  * ----------------
 603  */
 604 bool
 605 index_getnext_indexitem(IndexScanDesc scan,
 606                                                 ScanDirection direction)
 607 {
 608         FmgrInfo   *procedure;
 609         bool            found;
 610
 611         SCAN_CHECKS;
 612         GET_SCAN_PROCEDURE(amgettuple);
 613
 614         /* just make sure this is false... */
 615         scan->kill_prior_tuple = false;
 616
 617         /*
 618          * have the am's gettuple proc do all the work.
 619          */
 620         found = DatumGetBool(FunctionCall2(procedure,
 621                                                                            PointerGetDatum(scan),
 622                                                                            Int32GetDatum(direction)));
 623
 624         return found;
 625 }
 626
 627 /* ----------------
 628  *              index_getmulti - get multiple tuples from an index scan
 629  *
 630  * Collects the TIDs of multiple heap tuples satisfying the scan keys.
 631  * Since there's no interlock between the index scan and the eventual heap
 632  * access, this is only safe to use with MVCC-based snapshots: the heap
 633  * item slot could have been replaced by a newer tuple by the time we get
 634  * to it.
 635  *
 636  * A TRUE result indicates more calls should occur; a FALSE result says the
 637  * scan is done.  *returned_tids could be zero or nonzero in either case.
 638  * ----------------
 639  */
 640 bool
 641 index_getmulti(IndexScanDesc scan,
 642                            ItemPointer tids, int32 max_tids,
 643                            int32 *returned_tids)
 644 {
 645         FmgrInfo   *procedure;
 646         bool            found;
 647
 648         SCAN_CHECKS;
 649         GET_SCAN_PROCEDURE(amgetmulti);
 650
 651         /* just make sure this is false... */
 652         scan->kill_prior_tuple = false;
 653
 654         /*
 655          * have the am's getmulti proc do all the work.
 656          */
 657         found = DatumGetBool(FunctionCall4(procedure,
 658                                                                            PointerGetDatum(scan),
 659                                                                            PointerGetDatum(tids),
 660                                                                            Int32GetDatum(max_tids),
 661                                                                            PointerGetDatum(returned_tids)));
 662
 663         return found;
 664 }
 665
 666 /* ----------------
 667  *              index_bulk_delete - do mass deletion of index entries
 668  *
 669  *              callback routine tells whether a given main-heap tuple is
 670  *              to be deleted
 671  *
 672  *              return value is an optional palloc'd struct of statistics
 673  * ----------------
 674  */
 675 IndexBulkDeleteResult *
 676 index_bulk_delete(Relation indexRelation,
 677                                   IndexBulkDeleteCallback callback,
 678                                   void *callback_state)
 679 {
 680         FmgrInfo   *procedure;
 681         IndexBulkDeleteResult *result;
 682
 683         RELATION_CHECKS;
 684         GET_REL_PROCEDURE(ambulkdelete);
 685
 686         result = (IndexBulkDeleteResult *)
 687                 DatumGetPointer(FunctionCall3(procedure,
 688                                                                           PointerGetDatum(indexRelation),
 689                                                                           PointerGetDatum((Pointer) callback),
 690                                                                           PointerGetDatum(callback_state)));
 691
 692         return result;
 693 }
 694
 695 /* ----------------
 696  *              index_vacuum_cleanup - do post-deletion cleanup of an index
 697  *
 698  *              return value is an optional palloc'd struct of statistics
 699  * ----------------
 700  */
 701 IndexBulkDeleteResult *
 702 index_vacuum_cleanup(Relation indexRelation,
 703                                          IndexVacuumCleanupInfo *info,
 704                                          IndexBulkDeleteResult *stats)
 705 {
 706         FmgrInfo   *procedure;
 707         IndexBulkDeleteResult *result;
 708
 709         RELATION_CHECKS;
 710
 711         /* It's okay for an index AM not to have a vacuumcleanup procedure */
 712         if (!RegProcedureIsValid(indexRelation->rd_am->amvacuumcleanup))
 713                 return stats;
 714
 715         GET_REL_PROCEDURE(amvacuumcleanup);
 716
 717         result = (IndexBulkDeleteResult *)
 718                 DatumGetPointer(FunctionCall3(procedure,
 719                                                                           PointerGetDatum(indexRelation),
 720                                                                           PointerGetDatum((Pointer) info),
 721                                                                           PointerGetDatum((Pointer) stats)));
 722
 723         return result;
 724 }
 725
 726 /* ----------------
 727  *              index_getprocid
 728  *
 729  *              Some indexed access methods may require support routines that are
 730  *              not in the operator class/operator model imposed by pg_am.      These
 731  *              access methods may store the OIDs of registered procedures they
 732  *              need in pg_amproc.      These registered procedure OIDs are ordered in
 733  *              a way that makes sense to the access method, and used only by the
 734  *              access method.  The general index code doesn't know anything about
 735  *              the routines involved; it just builds an ordered list of them for
 736  *              each attribute on which an index is defined.
 737  *
 738  *              This routine returns the requested procedure OID for a particular
 739  *              indexed attribute.
 740  * ----------------
 741  */
 742 RegProcedure
 743 index_getprocid(Relation irel,
 744                                 AttrNumber attnum,
 745                                 uint16 procnum)
 746 {
 747         RegProcedure *loc;
 748         int                     nproc;
 749         int                     procindex;
 750
 751         nproc = irel->rd_am->amsupport;
 752
 753         Assert(procnum > 0 && procnum <= (uint16) nproc);
 754
 755         procindex = (nproc * (attnum - 1)) + (procnum - 1);
 756
 757         loc = irel->rd_support;
 758
 759         Assert(loc != NULL);
 760
 761         return loc[procindex];
 762 }
 763
 764 /* ----------------
 765  *              index_getprocinfo
 766  *
 767  *              This routine allows index AMs to keep fmgr lookup info for
 768  *              support procs in the relcache.
 769  *
 770  * Note: the return value points into cached data that will be lost during
 771  * any relcache rebuild!  Therefore, either use the callinfo right away,
 772  * or save it only after having acquired some type of lock on the index rel.
 773  * ----------------
 774  */
 775 FmgrInfo *
 776 index_getprocinfo(Relation irel,
 777                                   AttrNumber attnum,
 778                                   uint16 procnum)
 779 {
 780         FmgrInfo   *locinfo;
 781         int                     nproc;
 782         int                     procindex;
 783
 784         nproc = irel->rd_am->amsupport;
 785
 786         Assert(procnum > 0 && procnum <= (uint16) nproc);
 787
 788         procindex = (nproc * (attnum - 1)) + (procnum - 1);
 789
 790         locinfo = irel->rd_supportinfo;
 791
 792         Assert(locinfo != NULL);
 793
 794         locinfo += procindex;
 795
 796         /* Initialize the lookup info if first time through */
 797         if (locinfo->fn_oid == InvalidOid)
 798         {
 799                 RegProcedure *loc = irel->rd_support;
 800                 RegProcedure procId;
 801
 802                 Assert(loc != NULL);
 803
 804                 procId = loc[procindex];
 805
 806                 /*
 807                  * Complain if function was not found during
 808                  * IndexSupportInitialize. This should not happen unless the
 809                  * system tables contain bogus entries for the index opclass.  (If
 810                  * an AM wants to allow a support function to be optional, it can
 811                  * use index_getprocid.)
 812                  */
 813                 if (!RegProcedureIsValid(procId))
 814                         elog(ERROR, "missing support function %d for attribute %d of index \"%s\"",
 815                                  procnum, attnum, RelationGetRelationName(irel));
 816
 817                 fmgr_info_cxt(procId, locinfo, irel->rd_indexcxt);
 818         }
 819
 820         return locinfo;
 821 }