1 /*-------------------------------------------------------------------------
2 *
3 * indexam.c
4 * general index access method routines
5 *
6 * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 *
10 * IDENTIFICATION
11 * src/backend/access/index/indexam.c
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_parallelscan_estimate - estimate shared memory for parallel scan
24 * index_parallelscan_initialize - initialize parallel scan
25 * index_parallelrescan - (re)start a parallel scan of an index
26 * index_beginscan_parallel - join parallel index scan
27 * index_getnext_tid - get the next TID from a scan
28 * index_fetch_heap - get the scan's next heap tuple
29 * index_getnext_slot - get the next tuple from a scan
30 * index_getbitmap - get all tuples from a scan
31 * index_bulk_delete - bulk deletion of index tuples
32 * index_vacuum_cleanup - post-deletion cleanup of an index
33 * index_can_return - does index support index-only scans?
34 * index_getprocid - get a support procedure OID
35 * index_getprocinfo - get a support procedure's lookup info
36 *
37 * NOTES
38 * This file contains the index_ routines which used
39 * to be a scattered collection of stuff in access/genam.
40 *
41 *-------------------------------------------------------------------------
42 */
43
44 #include "postgres.h"
45
46 #include "access/amapi.h"
47 #include "access/heapam.h"
48 #include "access/reloptions.h"
49 #include "access/relscan.h"
50 #include "access/tableam.h"
51 #include "access/transam.h"
52 #include "access/xlog.h"
53 #include "catalog/index.h"
54 #include "catalog/pg_amproc.h"
55 #include "catalog/pg_type.h"
56 #include "commands/defrem.h"
57 #include "nodes/makefuncs.h"
58 #include "pgstat.h"
59 #include "storage/bufmgr.h"
60 #include "storage/lmgr.h"
61 #include "storage/predicate.h"
62 #include "utils/ruleutils.h"
63 #include "utils/snapmgr.h"
64 #include "utils/syscache.h"
65
66
67 /* ----------------------------------------------------------------
68 * macros used in index_ routines
69 *
70 * Note: the ReindexIsProcessingIndex() check in RELATION_CHECKS is there
71 * to check that we don't try to scan or do retail insertions into an index
72 * that is currently being rebuilt or pending rebuild. This helps to catch
73 * things that don't work when reindexing system catalogs. The assertion
74 * doesn't prevent the actual rebuild because we don't use RELATION_CHECKS
75 * when calling the index AM's ambuild routine, and there is no reason for
76 * ambuild to call its subsidiary routines through this file.
77 * ----------------------------------------------------------------
78 */
79 #define RELATION_CHECKS \
80 ( \
81 AssertMacro(RelationIsValid(indexRelation)), \
82 AssertMacro(PointerIsValid(indexRelation->rd_indam)), \
83 AssertMacro(!ReindexIsProcessingIndex(RelationGetRelid(indexRelation))) \
84 )
85
86 #define SCAN_CHECKS \
87 ( \
88 AssertMacro(IndexScanIsValid(scan)), \
89 AssertMacro(RelationIsValid(scan->indexRelation)), \
90 AssertMacro(PointerIsValid(scan->indexRelation->rd_indam)) \
91 )
92
93 #define CHECK_REL_PROCEDURE(pname) \
94 do { \
95 if (indexRelation->rd_indam->pname == NULL) \
96 elog(ERROR, "function %s is not defined for index %s", \
97 CppAsString(pname), RelationGetRelationName(indexRelation)); \
98 } while(0)
99
100 #define CHECK_SCAN_PROCEDURE(pname) \
101 do { \
102 if (scan->indexRelation->rd_indam->pname == NULL) \
103 elog(ERROR, "function %s is not defined for index %s", \
104 CppAsString(pname), RelationGetRelationName(scan->indexRelation)); \
105 } while(0)
106
107 static IndexScanDesc index_beginscan_internal(Relation indexRelation,
108 int nkeys, int norderbys, Snapshot snapshot,
109 ParallelIndexScanDesc pscan, bool temp_snap);
110
111
112 /* ----------------------------------------------------------------
113 * index_ interface functions
114 * ----------------------------------------------------------------
115 */
116
117 /* ----------------
118 * index_open - open an index relation by relation OID
119 *
120 * If lockmode is not "NoLock", the specified kind of lock is
121 * obtained on the index. (Generally, NoLock should only be
122 * used if the caller knows it has some appropriate lock on the
123 * index already.)
124 *
125 * An error is raised if the index does not exist.
126 *
127 * This is a convenience routine adapted for indexscan use.
128 * Some callers may prefer to use relation_open directly.
129 * ----------------
130 */
131 Relation
index_open(Oid relationId,LOCKMODE lockmode)132 index_open(Oid relationId, LOCKMODE lockmode)
133 {
134 Relation r;
135
136 r = relation_open(relationId, lockmode);
137
138 if (r->rd_rel->relkind != RELKIND_INDEX &&
139 r->rd_rel->relkind != RELKIND_PARTITIONED_INDEX)
140 ereport(ERROR,
141 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
142 errmsg("\"%s\" is not an index",
143 RelationGetRelationName(r))));
144
145 return r;
146 }
147
148 /* ----------------
149 * index_close - close an index relation
150 *
151 * If lockmode is not "NoLock", we then release the specified lock.
152 *
153 * Note that it is often sensible to hold a lock beyond index_close;
154 * in that case, the lock is released automatically at xact end.
155 * ----------------
156 */
157 void
index_close(Relation relation,LOCKMODE lockmode)158 index_close(Relation relation, LOCKMODE lockmode)
159 {
160 LockRelId relid = relation->rd_lockInfo.lockRelId;
161
162 Assert(lockmode >= NoLock && lockmode < MAX_LOCKMODES);
163
164 /* The relcache does the real work... */
165 RelationClose(relation);
166
167 if (lockmode != NoLock)
168 UnlockRelationId(&relid, lockmode);
169 }
170
171 /* ----------------
172 * index_insert - insert an index tuple into a relation
173 * ----------------
174 */
175 bool
index_insert(Relation indexRelation,Datum * values,bool * isnull,ItemPointer heap_t_ctid,Relation heapRelation,IndexUniqueCheck checkUnique,IndexInfo * indexInfo)176 index_insert(Relation indexRelation,
177 Datum *values,
178 bool *isnull,
179 ItemPointer heap_t_ctid,
180 Relation heapRelation,
181 IndexUniqueCheck checkUnique,
182 IndexInfo *indexInfo)
183 {
184 RELATION_CHECKS;
185 CHECK_REL_PROCEDURE(aminsert);
186
187 if (!(indexRelation->rd_indam->ampredlocks))
188 CheckForSerializableConflictIn(indexRelation,
189 (ItemPointer) NULL,
190 InvalidBlockNumber);
191
192 return indexRelation->rd_indam->aminsert(indexRelation, values, isnull,
193 heap_t_ctid, heapRelation,
194 checkUnique, indexInfo);
195 }
196
197 /*
198 * index_beginscan - start a scan of an index with amgettuple
199 *
200 * Caller must be holding suitable locks on the heap and the index.
201 */
202 IndexScanDesc
index_beginscan(Relation heapRelation,Relation indexRelation,Snapshot snapshot,int nkeys,int norderbys)203 index_beginscan(Relation heapRelation,
204 Relation indexRelation,
205 Snapshot snapshot,
206 int nkeys, int norderbys)
207 {
208 IndexScanDesc scan;
209
210 scan = index_beginscan_internal(indexRelation, nkeys, norderbys, snapshot, NULL, false);
211
212 /*
213 * Save additional parameters into the scandesc. Everything else was set
214 * up by RelationGetIndexScan.
215 */
216 scan->heapRelation = heapRelation;
217 scan->xs_snapshot = snapshot;
218
219 /* prepare to fetch index matches from table */
220 scan->xs_heapfetch = table_index_fetch_begin(heapRelation);
221
222 return scan;
223 }
224
225 /*
226 * index_beginscan_bitmap - start a scan of an index with amgetbitmap
227 *
228 * As above, caller had better be holding some lock on the parent heap
229 * relation, even though it's not explicitly mentioned here.
230 */
231 IndexScanDesc
index_beginscan_bitmap(Relation indexRelation,Snapshot snapshot,int nkeys)232 index_beginscan_bitmap(Relation indexRelation,
233 Snapshot snapshot,
234 int nkeys)
235 {
236 IndexScanDesc scan;
237
238 scan = index_beginscan_internal(indexRelation, nkeys, 0, snapshot, NULL, false);
239
240 /*
241 * Save additional parameters into the scandesc. Everything else was set
242 * up by RelationGetIndexScan.
243 */
244 scan->xs_snapshot = snapshot;
245
246 return scan;
247 }
248
249 /*
250 * index_beginscan_internal --- common code for index_beginscan variants
251 */
252 static IndexScanDesc
index_beginscan_internal(Relation indexRelation,int nkeys,int norderbys,Snapshot snapshot,ParallelIndexScanDesc pscan,bool temp_snap)253 index_beginscan_internal(Relation indexRelation,
254 int nkeys, int norderbys, Snapshot snapshot,
255 ParallelIndexScanDesc pscan, bool temp_snap)
256 {
257 IndexScanDesc scan;
258
259 RELATION_CHECKS;
260 CHECK_REL_PROCEDURE(ambeginscan);
261
262 if (!(indexRelation->rd_indam->ampredlocks))
263 PredicateLockRelation(indexRelation, snapshot);
264
265 /*
266 * We hold a reference count to the relcache entry throughout the scan.
267 */
268 RelationIncrementReferenceCount(indexRelation);
269
270 /*
271 * Tell the AM to open a scan.
272 */
273 scan = indexRelation->rd_indam->ambeginscan(indexRelation, nkeys,
274 norderbys);
275 /* Initialize information for parallel scan. */
276 scan->parallel_scan = pscan;
277 scan->xs_temp_snap = temp_snap;
278
279 return scan;
280 }
281
282 /* ----------------
283 * index_rescan - (re)start a scan of an index
284 *
285 * During a restart, the caller may specify a new set of scankeys and/or
286 * orderbykeys; but the number of keys cannot differ from what index_beginscan
287 * was told. (Later we might relax that to "must not exceed", but currently
288 * the index AMs tend to assume that scan->numberOfKeys is what to believe.)
289 * To restart the scan without changing keys, pass NULL for the key arrays.
290 * (Of course, keys *must* be passed on the first call, unless
291 * scan->numberOfKeys is zero.)
292 * ----------------
293 */
294 void
index_rescan(IndexScanDesc scan,ScanKey keys,int nkeys,ScanKey orderbys,int norderbys)295 index_rescan(IndexScanDesc scan,
296 ScanKey keys, int nkeys,
297 ScanKey orderbys, int norderbys)
298 {
299 SCAN_CHECKS;
300 CHECK_SCAN_PROCEDURE(amrescan);
301
302 Assert(nkeys == scan->numberOfKeys);
303 Assert(norderbys == scan->numberOfOrderBys);
304
305 /* Release resources (like buffer pins) from table accesses */
306 if (scan->xs_heapfetch)
307 table_index_fetch_reset(scan->xs_heapfetch);
308
309 scan->kill_prior_tuple = false; /* for safety */
310 scan->xs_heap_continue = false;
311
312 scan->indexRelation->rd_indam->amrescan(scan, keys, nkeys,
313 orderbys, norderbys);
314 }
315
316 /* ----------------
317 * index_endscan - end a scan
318 * ----------------
319 */
320 void
index_endscan(IndexScanDesc scan)321 index_endscan(IndexScanDesc scan)
322 {
323 SCAN_CHECKS;
324 CHECK_SCAN_PROCEDURE(amendscan);
325
326 /* Release resources (like buffer pins) from table accesses */
327 if (scan->xs_heapfetch)
328 {
329 table_index_fetch_end(scan->xs_heapfetch);
330 scan->xs_heapfetch = NULL;
331 }
332
333 /* End the AM's scan */
334 scan->indexRelation->rd_indam->amendscan(scan);
335
336 /* Release index refcount acquired by index_beginscan */
337 RelationDecrementReferenceCount(scan->indexRelation);
338
339 if (scan->xs_temp_snap)
340 UnregisterSnapshot(scan->xs_snapshot);
341
342 /* Release the scan data structure itself */
343 IndexScanEnd(scan);
344 }
345
346 /* ----------------
347 * index_markpos - mark a scan position
348 * ----------------
349 */
350 void
index_markpos(IndexScanDesc scan)351 index_markpos(IndexScanDesc scan)
352 {
353 SCAN_CHECKS;
354 CHECK_SCAN_PROCEDURE(ammarkpos);
355
356 scan->indexRelation->rd_indam->ammarkpos(scan);
357 }
358
359 /* ----------------
360 * index_restrpos - restore a scan position
361 *
362 * NOTE: this only restores the internal scan state of the index AM. See
363 * comments for ExecRestrPos().
364 *
365 * NOTE: For heap, in the presence of HOT chains, mark/restore only works
366 * correctly if the scan's snapshot is MVCC-safe; that ensures that there's at
367 * most one returnable tuple in each HOT chain, and so restoring the prior
368 * state at the granularity of the index AM is sufficient. Since the only
369 * current user of mark/restore functionality is nodeMergejoin.c, this
370 * effectively means that merge-join plans only work for MVCC snapshots. This
371 * could be fixed if necessary, but for now it seems unimportant.
372 * ----------------
373 */
374 void
index_restrpos(IndexScanDesc scan)375 index_restrpos(IndexScanDesc scan)
376 {
377 Assert(IsMVCCSnapshot(scan->xs_snapshot));
378
379 SCAN_CHECKS;
380 CHECK_SCAN_PROCEDURE(amrestrpos);
381
382 /* release resources (like buffer pins) from table accesses */
383 if (scan->xs_heapfetch)
384 table_index_fetch_reset(scan->xs_heapfetch);
385
386 scan->kill_prior_tuple = false; /* for safety */
387 scan->xs_heap_continue = false;
388
389 scan->indexRelation->rd_indam->amrestrpos(scan);
390 }
391
392 /*
393 * index_parallelscan_estimate - estimate shared memory for parallel scan
394 *
395 * Currently, we don't pass any information to the AM-specific estimator,
396 * so it can probably only return a constant. In the future, we might need
397 * to pass more information.
398 */
399 Size
index_parallelscan_estimate(Relation indexRelation,Snapshot snapshot)400 index_parallelscan_estimate(Relation indexRelation, Snapshot snapshot)
401 {
402 Size nbytes;
403
404 RELATION_CHECKS;
405
406 nbytes = offsetof(ParallelIndexScanDescData, ps_snapshot_data);
407 nbytes = add_size(nbytes, EstimateSnapshotSpace(snapshot));
408 nbytes = MAXALIGN(nbytes);
409
410 /*
411 * If amestimateparallelscan is not provided, assume there is no
412 * AM-specific data needed. (It's hard to believe that could work, but
413 * it's easy enough to cater to it here.)
414 */
415 if (indexRelation->rd_indam->amestimateparallelscan != NULL)
416 nbytes = add_size(nbytes,
417 indexRelation->rd_indam->amestimateparallelscan());
418
419 return nbytes;
420 }
421
422 /*
423 * index_parallelscan_initialize - initialize parallel scan
424 *
425 * We initialize both the ParallelIndexScanDesc proper and the AM-specific
426 * information which follows it.
427 *
428 * This function calls access method specific initialization routine to
429 * initialize am specific information. Call this just once in the leader
430 * process; then, individual workers attach via index_beginscan_parallel.
431 */
432 void
index_parallelscan_initialize(Relation heapRelation,Relation indexRelation,Snapshot snapshot,ParallelIndexScanDesc target)433 index_parallelscan_initialize(Relation heapRelation, Relation indexRelation,
434 Snapshot snapshot, ParallelIndexScanDesc target)
435 {
436 Size offset;
437
438 RELATION_CHECKS;
439
440 offset = add_size(offsetof(ParallelIndexScanDescData, ps_snapshot_data),
441 EstimateSnapshotSpace(snapshot));
442 offset = MAXALIGN(offset);
443
444 target->ps_relid = RelationGetRelid(heapRelation);
445 target->ps_indexid = RelationGetRelid(indexRelation);
446 target->ps_offset = offset;
447 SerializeSnapshot(snapshot, target->ps_snapshot_data);
448
449 /* aminitparallelscan is optional; assume no-op if not provided by AM */
450 if (indexRelation->rd_indam->aminitparallelscan != NULL)
451 {
452 void *amtarget;
453
454 amtarget = OffsetToPointer(target, offset);
455 indexRelation->rd_indam->aminitparallelscan(amtarget);
456 }
457 }
458
459 /* ----------------
460 * index_parallelrescan - (re)start a parallel scan of an index
461 * ----------------
462 */
463 void
index_parallelrescan(IndexScanDesc scan)464 index_parallelrescan(IndexScanDesc scan)
465 {
466 SCAN_CHECKS;
467
468 if (scan->xs_heapfetch)
469 table_index_fetch_reset(scan->xs_heapfetch);
470
471 /* amparallelrescan is optional; assume no-op if not provided by AM */
472 if (scan->indexRelation->rd_indam->amparallelrescan != NULL)
473 scan->indexRelation->rd_indam->amparallelrescan(scan);
474 }
475
476 /*
477 * index_beginscan_parallel - join parallel index scan
478 *
479 * Caller must be holding suitable locks on the heap and the index.
480 */
481 IndexScanDesc
index_beginscan_parallel(Relation heaprel,Relation indexrel,int nkeys,int norderbys,ParallelIndexScanDesc pscan)482 index_beginscan_parallel(Relation heaprel, Relation indexrel, int nkeys,
483 int norderbys, ParallelIndexScanDesc pscan)
484 {
485 Snapshot snapshot;
486 IndexScanDesc scan;
487
488 Assert(RelationGetRelid(heaprel) == pscan->ps_relid);
489 snapshot = RestoreSnapshot(pscan->ps_snapshot_data);
490 RegisterSnapshot(snapshot);
491 scan = index_beginscan_internal(indexrel, nkeys, norderbys, snapshot,
492 pscan, true);
493
494 /*
495 * Save additional parameters into the scandesc. Everything else was set
496 * up by index_beginscan_internal.
497 */
498 scan->heapRelation = heaprel;
499 scan->xs_snapshot = snapshot;
500
501 /* prepare to fetch index matches from table */
502 scan->xs_heapfetch = table_index_fetch_begin(heaprel);
503
504 return scan;
505 }
506
507 /* ----------------
508 * index_getnext_tid - get the next TID from a scan
509 *
510 * The result is the next TID satisfying the scan keys,
511 * or NULL if no more matching tuples exist.
512 * ----------------
513 */
514 ItemPointer
index_getnext_tid(IndexScanDesc scan,ScanDirection direction)515 index_getnext_tid(IndexScanDesc scan, ScanDirection direction)
516 {
517 bool found;
518
519 SCAN_CHECKS;
520 CHECK_SCAN_PROCEDURE(amgettuple);
521
522 Assert(TransactionIdIsValid(RecentGlobalXmin));
523
524 /*
525 * The AM's amgettuple proc finds the next index entry matching the scan
526 * keys, and puts the TID into scan->xs_heaptid. It should also set
527 * scan->xs_recheck and possibly scan->xs_itup/scan->xs_hitup, though we
528 * pay no attention to those fields here.
529 */
530 found = scan->indexRelation->rd_indam->amgettuple(scan, direction);
531
532 /* Reset kill flag immediately for safety */
533 scan->kill_prior_tuple = false;
534 scan->xs_heap_continue = false;
535
536 /* If we're out of index entries, we're done */
537 if (!found)
538 {
539 /* release resources (like buffer pins) from table accesses */
540 if (scan->xs_heapfetch)
541 table_index_fetch_reset(scan->xs_heapfetch);
542
543 return NULL;
544 }
545 Assert(ItemPointerIsValid(&scan->xs_heaptid));
546
547 pgstat_count_index_tuples(scan->indexRelation, 1);
548
549 /* Return the TID of the tuple we found. */
550 return &scan->xs_heaptid;
551 }
552
553 /* ----------------
554 * index_fetch_heap - get the scan's next heap tuple
555 *
556 * The result is a visible heap tuple associated with the index TID most
557 * recently fetched by index_getnext_tid, or NULL if no more matching tuples
558 * exist. (There can be more than one matching tuple because of HOT chains,
559 * although when using an MVCC snapshot it should be impossible for more than
560 * one such tuple to exist.)
561 *
562 * On success, the buffer containing the heap tup is pinned (the pin will be
563 * dropped in a future index_getnext_tid, index_fetch_heap or index_endscan
564 * call).
565 *
566 * Note: caller must check scan->xs_recheck, and perform rechecking of the
567 * scan keys if required. We do not do that here because we don't have
568 * enough information to do it efficiently in the general case.
569 * ----------------
570 */
571 bool
index_fetch_heap(IndexScanDesc scan,TupleTableSlot * slot)572 index_fetch_heap(IndexScanDesc scan, TupleTableSlot *slot)
573 {
574 bool all_dead = false;
575 bool found;
576
577 found = table_index_fetch_tuple(scan->xs_heapfetch, &scan->xs_heaptid,
578 scan->xs_snapshot, slot,
579 &scan->xs_heap_continue, &all_dead);
580
581 if (found)
582 pgstat_count_heap_fetch(scan->indexRelation);
583
584 /*
585 * If we scanned a whole HOT chain and found only dead tuples, tell index
586 * AM to kill its entry for that TID (this will take effect in the next
587 * amgettuple call, in index_getnext_tid). We do not do this when in
588 * recovery because it may violate MVCC to do so. See comments in
589 * RelationGetIndexScan().
590 */
591 if (!scan->xactStartedInRecovery)
592 scan->kill_prior_tuple = all_dead;
593
594 return found;
595 }
596
597 /* ----------------
598 * index_getnext_slot - get the next tuple from a scan
599 *
600 * The result is true if a tuple satisfying the scan keys and the snapshot was
601 * found, false otherwise. The tuple is stored in the specified slot.
602 *
603 * On success, resources (like buffer pins) are likely to be held, and will be
604 * dropped by a future index_getnext_tid, index_fetch_heap or index_endscan
605 * call).
606 *
607 * Note: caller must check scan->xs_recheck, and perform rechecking of the
608 * scan keys if required. We do not do that here because we don't have
609 * enough information to do it efficiently in the general case.
610 * ----------------
611 */
612 bool
index_getnext_slot(IndexScanDesc scan,ScanDirection direction,TupleTableSlot * slot)613 index_getnext_slot(IndexScanDesc scan, ScanDirection direction, TupleTableSlot *slot)
614 {
615 for (;;)
616 {
617 if (!scan->xs_heap_continue)
618 {
619 ItemPointer tid;
620
621 /* Time to fetch the next TID from the index */
622 tid = index_getnext_tid(scan, direction);
623
624 /* If we're out of index entries, we're done */
625 if (tid == NULL)
626 break;
627
628 Assert(ItemPointerEquals(tid, &scan->xs_heaptid));
629 }
630
631 /*
632 * Fetch the next (or only) visible heap tuple for this index entry.
633 * If we don't find anything, loop around and grab the next TID from
634 * the index.
635 */
636 Assert(ItemPointerIsValid(&scan->xs_heaptid));
637 if (index_fetch_heap(scan, slot))
638 return true;
639 }
640
641 return false;
642 }
643
644 /* ----------------
645 * index_getbitmap - get all tuples at once from an index scan
646 *
647 * Adds the TIDs of all heap tuples satisfying the scan keys to a bitmap.
648 * Since there's no interlock between the index scan and the eventual heap
649 * access, this is only safe to use with MVCC-based snapshots: the heap
650 * item slot could have been replaced by a newer tuple by the time we get
651 * to it.
652 *
653 * Returns the number of matching tuples found. (Note: this might be only
654 * approximate, so it should only be used for statistical purposes.)
655 * ----------------
656 */
657 int64
index_getbitmap(IndexScanDesc scan,TIDBitmap * bitmap)658 index_getbitmap(IndexScanDesc scan, TIDBitmap *bitmap)
659 {
660 int64 ntids;
661
662 SCAN_CHECKS;
663 CHECK_SCAN_PROCEDURE(amgetbitmap);
664
665 /* just make sure this is false... */
666 scan->kill_prior_tuple = false;
667
668 /*
669 * have the am's getbitmap proc do all the work.
670 */
671 ntids = scan->indexRelation->rd_indam->amgetbitmap(scan, bitmap);
672
673 pgstat_count_index_tuples(scan->indexRelation, ntids);
674
675 return ntids;
676 }
677
678 /* ----------------
679 * index_bulk_delete - do mass deletion of index entries
680 *
681 * callback routine tells whether a given main-heap tuple is
682 * to be deleted
683 *
684 * return value is an optional palloc'd struct of statistics
685 * ----------------
686 */
687 IndexBulkDeleteResult *
index_bulk_delete(IndexVacuumInfo * info,IndexBulkDeleteResult * stats,IndexBulkDeleteCallback callback,void * callback_state)688 index_bulk_delete(IndexVacuumInfo *info,
689 IndexBulkDeleteResult *stats,
690 IndexBulkDeleteCallback callback,
691 void *callback_state)
692 {
693 Relation indexRelation = info->index;
694
695 RELATION_CHECKS;
696 CHECK_REL_PROCEDURE(ambulkdelete);
697
698 return indexRelation->rd_indam->ambulkdelete(info, stats,
699 callback, callback_state);
700 }
701
702 /* ----------------
703 * index_vacuum_cleanup - do post-deletion cleanup of an index
704 *
705 * return value is an optional palloc'd struct of statistics
706 * ----------------
707 */
708 IndexBulkDeleteResult *
index_vacuum_cleanup(IndexVacuumInfo * info,IndexBulkDeleteResult * stats)709 index_vacuum_cleanup(IndexVacuumInfo *info,
710 IndexBulkDeleteResult *stats)
711 {
712 Relation indexRelation = info->index;
713
714 RELATION_CHECKS;
715 CHECK_REL_PROCEDURE(amvacuumcleanup);
716
717 return indexRelation->rd_indam->amvacuumcleanup(info, stats);
718 }
719
720 /* ----------------
721 * index_can_return
722 *
723 * Does the index access method support index-only scans for the given
724 * column?
725 * ----------------
726 */
727 bool
index_can_return(Relation indexRelation,int attno)728 index_can_return(Relation indexRelation, int attno)
729 {
730 RELATION_CHECKS;
731
732 /* amcanreturn is optional; assume false if not provided by AM */
733 if (indexRelation->rd_indam->amcanreturn == NULL)
734 return false;
735
736 return indexRelation->rd_indam->amcanreturn(indexRelation, attno);
737 }
738
739 /* ----------------
740 * index_getprocid
741 *
742 * Index access methods typically require support routines that are
743 * not directly the implementation of any WHERE-clause query operator
744 * and so cannot be kept in pg_amop. Instead, such routines are kept
745 * in pg_amproc. These registered procedure OIDs are assigned numbers
746 * according to a convention established by the access method.
747 * The general index code doesn't know anything about the routines
748 * involved; it just builds an ordered list of them for
749 * each attribute on which an index is defined.
750 *
751 * As of Postgres 8.3, support routines within an operator family
752 * are further subdivided by the "left type" and "right type" of the
753 * query operator(s) that they support. The "default" functions for a
754 * particular indexed attribute are those with both types equal to
755 * the index opclass' opcintype (note that this is subtly different
756 * from the indexed attribute's own type: it may be a binary-compatible
757 * type instead). Only the default functions are stored in relcache
758 * entries --- access methods can use the syscache to look up non-default
759 * functions.
760 *
761 * This routine returns the requested default procedure OID for a
762 * particular indexed attribute.
763 * ----------------
764 */
765 RegProcedure
index_getprocid(Relation irel,AttrNumber attnum,uint16 procnum)766 index_getprocid(Relation irel,
767 AttrNumber attnum,
768 uint16 procnum)
769 {
770 RegProcedure *loc;
771 int nproc;
772 int procindex;
773
774 nproc = irel->rd_indam->amsupport;
775
776 Assert(procnum > 0 && procnum <= (uint16) nproc);
777
778 procindex = (nproc * (attnum - 1)) + (procnum - 1);
779
780 loc = irel->rd_support;
781
782 Assert(loc != NULL);
783
784 return loc[procindex];
785 }
786
787 /* ----------------
788 * index_getprocinfo
789 *
790 * This routine allows index AMs to keep fmgr lookup info for
791 * support procs in the relcache. As above, only the "default"
792 * functions for any particular indexed attribute are cached.
793 *
794 * Note: the return value points into cached data that will be lost during
795 * any relcache rebuild! Therefore, either use the callinfo right away,
796 * or save it only after having acquired some type of lock on the index rel.
797 * ----------------
798 */
799 FmgrInfo *
index_getprocinfo(Relation irel,AttrNumber attnum,uint16 procnum)800 index_getprocinfo(Relation irel,
801 AttrNumber attnum,
802 uint16 procnum)
803 {
804 FmgrInfo *locinfo;
805 int nproc;
806 int optsproc;
807 int procindex;
808
809 nproc = irel->rd_indam->amsupport;
810 optsproc = irel->rd_indam->amoptsprocnum;
811
812 Assert(procnum > 0 && procnum <= (uint16) nproc);
813
814 procindex = (nproc * (attnum - 1)) + (procnum - 1);
815
816 locinfo = irel->rd_supportinfo;
817
818 Assert(locinfo != NULL);
819
820 locinfo += procindex;
821
822 /* Initialize the lookup info if first time through */
823 if (locinfo->fn_oid == InvalidOid)
824 {
825 RegProcedure *loc = irel->rd_support;
826 RegProcedure procId;
827
828 Assert(loc != NULL);
829
830 procId = loc[procindex];
831
832 /*
833 * Complain if function was not found during IndexSupportInitialize.
834 * This should not happen unless the system tables contain bogus
835 * entries for the index opclass. (If an AM wants to allow a support
836 * function to be optional, it can use index_getprocid.)
837 */
838 if (!RegProcedureIsValid(procId))
839 elog(ERROR, "missing support function %d for attribute %d of index \"%s\"",
840 procnum, attnum, RelationGetRelationName(irel));
841
842 fmgr_info_cxt(procId, locinfo, irel->rd_indexcxt);
843
844 if (procnum != optsproc)
845 {
846 /* Initialize locinfo->fn_expr with opclass options Const */
847 bytea **attoptions = RelationGetIndexAttOptions(irel, false);
848 MemoryContext oldcxt = MemoryContextSwitchTo(irel->rd_indexcxt);
849
850 set_fn_opclass_options(locinfo, attoptions[attnum - 1]);
851
852 MemoryContextSwitchTo(oldcxt);
853 }
854 }
855
856 return locinfo;
857 }
858
859 /* ----------------
860 * index_store_float8_orderby_distances
861 *
862 * Convert AM distance function's results (that can be inexact)
863 * to ORDER BY types and save them into xs_orderbyvals/xs_orderbynulls
864 * for a possible recheck.
865 * ----------------
866 */
867 void
index_store_float8_orderby_distances(IndexScanDesc scan,Oid * orderByTypes,IndexOrderByDistance * distances,bool recheckOrderBy)868 index_store_float8_orderby_distances(IndexScanDesc scan, Oid *orderByTypes,
869 IndexOrderByDistance *distances,
870 bool recheckOrderBy)
871 {
872 int i;
873
874 Assert(distances || !recheckOrderBy);
875
876 scan->xs_recheckorderby = recheckOrderBy;
877
878 for (i = 0; i < scan->numberOfOrderBys; i++)
879 {
880 if (orderByTypes[i] == FLOAT8OID)
881 {
882 #ifndef USE_FLOAT8_BYVAL
883 /* must free any old value to avoid memory leakage */
884 if (!scan->xs_orderbynulls[i])
885 pfree(DatumGetPointer(scan->xs_orderbyvals[i]));
886 #endif
887 if (distances && !distances[i].isnull)
888 {
889 scan->xs_orderbyvals[i] = Float8GetDatum(distances[i].value);
890 scan->xs_orderbynulls[i] = false;
891 }
892 else
893 {
894 scan->xs_orderbyvals[i] = (Datum) 0;
895 scan->xs_orderbynulls[i] = true;
896 }
897 }
898 else if (orderByTypes[i] == FLOAT4OID)
899 {
900 /* convert distance function's result to ORDER BY type */
901 if (distances && !distances[i].isnull)
902 {
903 scan->xs_orderbyvals[i] = Float4GetDatum((float4) distances[i].value);
904 scan->xs_orderbynulls[i] = false;
905 }
906 else
907 {
908 scan->xs_orderbyvals[i] = (Datum) 0;
909 scan->xs_orderbynulls[i] = true;
910 }
911 }
912 else
913 {
914 /*
915 * If the ordering operator's return value is anything else, we
916 * don't know how to convert the float8 bound calculated by the
917 * distance function to that. The executor won't actually need
918 * the order by values we return here, if there are no lossy
919 * results, so only insist on converting if the *recheck flag is
920 * set.
921 */
922 if (scan->xs_recheckorderby)
923 elog(ERROR, "ORDER BY operator must return float8 or float4 if the distance function is lossy");
924 scan->xs_orderbynulls[i] = true;
925 }
926 }
927 }
928
929 /* ----------------
930 * index_opclass_options
931 *
932 * Parse opclass-specific options for index column.
933 * ----------------
934 */
935 bytea *
index_opclass_options(Relation indrel,AttrNumber attnum,Datum attoptions,bool validate)936 index_opclass_options(Relation indrel, AttrNumber attnum, Datum attoptions,
937 bool validate)
938 {
939 int amoptsprocnum = indrel->rd_indam->amoptsprocnum;
940 Oid procid = InvalidOid;
941 FmgrInfo *procinfo;
942 local_relopts relopts;
943
944 /* fetch options support procedure if specified */
945 if (amoptsprocnum != 0)
946 procid = index_getprocid(indrel, attnum, amoptsprocnum);
947
948 if (!OidIsValid(procid))
949 {
950 Oid opclass;
951 Datum indclassDatum;
952 oidvector *indclass;
953 bool isnull;
954
955 if (!DatumGetPointer(attoptions))
956 return NULL; /* ok, no options, no procedure */
957
958 /*
959 * Report an error if the opclass's options-parsing procedure does not
960 * exist but the opclass options are specified.
961 */
962 indclassDatum = SysCacheGetAttr(INDEXRELID, indrel->rd_indextuple,
963 Anum_pg_index_indclass, &isnull);
964 Assert(!isnull);
965 indclass = (oidvector *) DatumGetPointer(indclassDatum);
966 opclass = indclass->values[attnum - 1];
967
968 ereport(ERROR,
969 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
970 errmsg("operator class %s has no options",
971 generate_opclass_name(opclass))));
972 }
973
974 init_local_reloptions(&relopts, 0);
975
976 procinfo = index_getprocinfo(indrel, attnum, amoptsprocnum);
977
978 (void) FunctionCall1(procinfo, PointerGetDatum(&relopts));
979
980 return build_local_reloptions(&relopts, attoptions, validate);
981 }
982