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indxpath.c File Reference
#include "postgres.h"#include "access/stratnum.h"#include "access/sysattr.h"#include "access/transam.h"#include "catalog/pg_am.h"#include "catalog/pg_amop.h"#include "catalog/pg_operator.h"#include "catalog/pg_opfamily.h"#include "catalog/pg_type.h"#include "nodes/makefuncs.h"#include "nodes/nodeFuncs.h"#include "nodes/supportnodes.h"#include "optimizer/cost.h"#include "optimizer/optimizer.h"#include "optimizer/pathnode.h"#include "optimizer/paths.h"#include "optimizer/prep.h"#include "optimizer/restrictinfo.h"#include "utils/lsyscache.h"#include "utils/selfuncs.h"
Include dependency graph for indxpath.c:
Go to the source code of this file.
Data Structures | |
| struct | IndexClauseSet |
| struct | PathClauseUsage |
| struct | ec_member_matches_arg |
| struct | OrArgIndexMatch |
Macros | |
| #define | IndexCollMatchesExprColl(idxcollation, exprcollation) ((idxcollation) == InvalidOid || (idxcollation) == (exprcollation)) |
Enumerations | |
| enum | ScanTypeControl { ST_INDEXSCAN , ST_BITMAPSCAN , ST_ANYSCAN } |
Macro Definition Documentation
◆ IndexCollMatchesExprColl
| #define IndexCollMatchesExprColl | ( | idxcollation, | |
| exprcollation | |||
| ) | ((idxcollation) == InvalidOid || (idxcollation) == (exprcollation)) |
Definition at line 40 of file indxpath.c.
44{
48} ScanTypeControl;
49
50/* Data structure for collecting qual clauses that match an index */
51typedef struct
52{
53 bool nonempty; /* True if lists are not all empty */
54 /* Lists of IndexClause nodes, one list per index column */
56} IndexClauseSet;
57
58/* Per-path data used within choose_bitmap_and() */
59typedef struct
60{
65 bool unclassifiable; /* has too many quals+preds to process? */
66} PathClauseUsage;
67
68/* Callback argument for ec_member_matches_indexcol */
69typedef struct
70{
72 int indexcol; /* index column we want to match to */
74
75
97 Relids relids,
114 List *paths);
119 List *paths);
129 double rowcount);
142 List *clauses,
146 RestrictInfo *rinfo,
150 RestrictInfo *rinfo,
151 int indexcol,
155 RestrictInfo *rinfo,
158 RestrictInfo *rinfo,
159 int indexcol,
162 RestrictInfo *rinfo,
163 int indexcol,
166 RestrictInfo *rinfo,
167 Oid funcid,
168 int indexarg,
169 int indexcol,
172 RestrictInfo *rinfo,
173 int indexcol,
176 RestrictInfo *rinfo,
177 int indexcol,
180 RestrictInfo *rinfo,
181 int indexcol,
184 RestrictInfo *rinfo,
185 int indexcol,
199
200
201/*
202 * create_index_paths()
203 * Generate all interesting index paths for the given relation.
204 * Candidate paths are added to the rel's pathlist (using add_path).
205 *
206 * To be considered for an index scan, an index must match one or more
207 * restriction clauses or join clauses from the query's qual condition,
208 * or match the query's ORDER BY condition, or have a predicate that
209 * matches the query's qual condition.
210 *
211 * There are two basic kinds of index scans. A "plain" index scan uses
212 * only restriction clauses (possibly none at all) in its indexqual,
213 * so it can be applied in any context. A "parameterized" index scan uses
214 * join clauses (plus restriction clauses, if available) in its indexqual.
215 * When joining such a scan to one of the relations supplying the other
216 * variables used in its indexqual, the parameterized scan must appear as
217 * the inner relation of a nestloop join; it can't be used on the outer side,
218 * nor in a merge or hash join. In that context, values for the other rels'
219 * attributes are available and fixed during any one scan of the indexpath.
220 *
221 * An IndexPath is generated and submitted to add_path() for each plain or
222 * parameterized index scan this routine deems potentially interesting for
223 * the current query.
224 *
225 * 'rel' is the relation for which we want to generate index paths
226 *
227 * Note: check_index_predicates() must have been run previously for this rel.
228 *
229 * Note: in cases involving LATERAL references in the relation's tlist, it's
230 * possible that rel->lateral_relids is nonempty. Currently, we include
231 * lateral_relids into the parameterization reported for each path, but don't
232 * take it into account otherwise. The fact that any such rels *must* be
233 * available as parameter sources perhaps should influence our choices of
234 * index quals ... but for now, it doesn't seem worth troubling over.
235 * In particular, comments below about "unparameterized" paths should be read
236 * as meaning "unparameterized so far as the indexquals are concerned".
237 */
238void
240{
249
250 /* Skip the whole mess if no indexes */
252 return;
253
254 /* Bitmap paths are collected and then dealt with at the end */
256
257 /* Examine each index in turn */
259 {
261
262 /* Protect limited-size array in IndexClauseSets */
264
265 /*
266 * Ignore partial indexes that do not match the query.
267 * (generate_bitmap_or_paths() might be able to do something with
268 * them, but that's of no concern here.)
269 */
271 continue;
272
273 /*
274 * Identify the restriction clauses that can match the index.
275 */
278
279 /*
280 * Build index paths from the restriction clauses. These will be
281 * non-parameterized paths. Plain paths go directly to add_path(),
282 * bitmap paths are added to bitindexpaths to be handled below.
283 */
285 &bitindexpaths);
286
287 /*
288 * Identify the join clauses that can match the index. For the moment
289 * we keep them separate from the restriction clauses. Note that this
290 * step finds only "loose" join clauses that have not been merged into
291 * EquivalenceClasses. Also, collect join OR clauses for later.
292 */
296
297 /*
298 * Look for EquivalenceClasses that can generate joinclauses matching
299 * the index.
300 */
303 &eclauseset);
304
305 /*
306 * If we found any plain or eclass join clauses, build parameterized
307 * index paths using them.
308 */
311 &rclauseset,
312 &jclauseset,
313 &eclauseset,
314 &bitjoinpaths);
315 }
316
317 /*
318 * Generate BitmapOrPaths for any suitable OR-clauses present in the
319 * restriction list. Add these to bitindexpaths.
320 */
324
325 /*
326 * Likewise, generate BitmapOrPaths for any suitable OR-clauses present in
327 * the joinclause list. Add these to bitjoinpaths.
328 */
332
333 /*
334 * If we found anything usable, generate a BitmapHeapPath for the most
335 * promising combination of restriction bitmap index paths. Note there
336 * will be only one such path no matter how many indexes exist. This
337 * should be sufficient since there's basically only one figure of merit
338 * (total cost) for such a path.
339 */
341 {
342 Path *bitmapqual;
344
347 rel->lateral_relids, 1.0, 0);
349
350 /* create a partial bitmap heap path */
353 }
354
355 /*
356 * Likewise, if we found anything usable, generate BitmapHeapPaths for the
357 * most promising combinations of join bitmap index paths. Our strategy
358 * is to generate one such path for each distinct parameterization seen
359 * among the available bitmap index paths. This may look pretty
360 * expensive, but usually there won't be very many distinct
361 * parameterizations. (This logic is quite similar to that in
362 * consider_index_join_clauses, but we're working with whole paths not
363 * individual clauses.)
364 */
366 {
368
369 /* Identify each distinct parameterization seen in bitjoinpaths */
372 {
375
377 required_outer);
378 }
379
380 /* Now, for each distinct parameterization set ... */
382 {
385 Path *bitmapqual;
390
391 /* Identify all the bitmap join paths needing no more than that */
394 {
396
399 }
400
401 /*
402 * Add in restriction bitmap paths, since they can be used
403 * together with any join paths.
404 */
406
407 /* Select best AND combination for this parameterization */
409
410 /* And push that path into the mix */
416 }
417 }
418}
419
420/*
421 * consider_index_join_clauses
422 * Given sets of join clauses for an index, decide which parameterized
423 * index paths to build.
424 *
425 * Plain indexpaths are sent directly to add_path, while potential
426 * bitmap indexpaths are added to *bitindexpaths for later processing.
427 *
428 * 'rel' is the index's heap relation
429 * 'index' is the index for which we want to generate paths
430 * 'rclauseset' is the collection of indexable restriction clauses
431 * 'jclauseset' is the collection of indexable simple join clauses
432 * 'eclauseset' is the collection of indexable clauses from EquivalenceClasses
433 * '*bitindexpaths' is the list to add bitmap paths to
434 */
435static void
442{
445 int indexcol;
446
447 /*
448 * The strategy here is to identify every potentially useful set of outer
449 * rels that can provide indexable join clauses. For each such set,
450 * select all the join clauses available from those outer rels, add on all
451 * the indexable restriction clauses, and generate plain and/or bitmap
452 * index paths for that set of clauses. This is based on the assumption
453 * that it's always better to apply a clause as an indexqual than as a
454 * filter (qpqual); which is where an available clause would end up being
455 * applied if we omit it from the indexquals.
456 *
457 * This looks expensive, but in most practical cases there won't be very
458 * many distinct sets of outer rels to consider. As a safety valve when
459 * that's not true, we use a heuristic: limit the number of outer rel sets
460 * considered to a multiple of the number of clauses considered. (We'll
461 * always consider using each individual join clause, though.)
462 *
463 * For simplicity in selecting relevant clauses, we represent each set of
464 * outer rels as a maximum set of clause_relids --- that is, the indexed
465 * relation itself is also included in the relids set. considered_relids
466 * lists all relids sets we've already tried.
467 */
469 {
470 /* Consider each applicable simple join clause */
474 bitindexpaths,
475 jclauseset->indexclauses[indexcol],
476 considered_clauses,
477 &considered_relids);
478 /* Consider each applicable eclass join clause */
482 bitindexpaths,
483 eclauseset->indexclauses[indexcol],
484 considered_clauses,
485 &considered_relids);
486 }
487}
488
489/*
490 * consider_index_join_outer_rels
491 * Generate parameterized paths based on clause relids in the clause list.
492 *
493 * Workhorse for consider_index_join_clauses; see notes therein for rationale.
494 *
495 * 'rel', 'index', 'rclauseset', 'jclauseset', 'eclauseset', and
496 * 'bitindexpaths' as above
497 * 'indexjoinclauses' is a list of IndexClauses for join clauses
498 * 'considered_clauses' is the total number of clauses considered (so far)
499 * '*considered_relids' is a list of all relids sets already considered
500 */
501static void
511{
513
514 /* Examine relids of each joinclause in the given list */
516 {
521
522 /* If we already tried its relids set, no need to do so again */
524 continue;
525
526 /*
527 * Generate the union of this clause's relids set with each
528 * previously-tried set. This ensures we try this clause along with
529 * every interesting subset of previous clauses. However, to avoid
530 * exponential growth of planning time when there are many clauses,
531 * limit the number of relid sets accepted to 10 * considered_clauses.
532 *
533 * Note: get_join_index_paths appends entries to *considered_relids,
534 * but we do not need to visit such newly-added entries within this
535 * loop, so we don't use foreach() here. No real harm would be done
536 * if we did visit them, since the subset check would reject them; but
537 * it would waste some cycles.
538 */
541 {
543
544 /*
545 * If either is a subset of the other, no new set is possible.
546 * This isn't a complete test for redundancy, but it's easy and
547 * cheap. get_join_index_paths will check more carefully if we
548 * already generated the same relids set.
549 */
551 continue;
552
553 /*
554 * If this clause was derived from an equivalence class, the
555 * clause list may contain other clauses derived from the same
556 * eclass. We should not consider that combining this clause with
557 * one of those clauses generates a usefully different
558 * parameterization; so skip if any clause derived from the same
559 * eclass would already have been included when using oldrelids.
560 */
561 if (parent_ec &&
563 indexjoinclauses))
564 continue;
565
566 /*
567 * If the number of relid sets considered exceeds our heuristic
568 * limit, stop considering combinations of clauses. We'll still
569 * consider the current clause alone, though (below this loop).
570 */
572 break;
573
574 /* OK, try the union set */
577 bitindexpaths,
579 considered_relids);
580 }
581
582 /* Also try this set of relids by itself */
585 bitindexpaths,
586 clause_relids,
587 considered_relids);
588 }
589}
590
591/*
592 * get_join_index_paths
593 * Generate index paths using clauses from the specified outer relations.
594 * In addition to generating paths, relids is added to *considered_relids
595 * if not already present.
596 *
597 * Workhorse for consider_index_join_clauses; see notes therein for rationale.
598 *
599 * 'rel', 'index', 'rclauseset', 'jclauseset', 'eclauseset',
600 * 'bitindexpaths', 'considered_relids' as above
601 * 'relids' is the current set of relids to consider (the target rel plus
602 * one or more outer rels)
603 */
604static void
611 Relids relids,
613{
615 int indexcol;
616
617 /* If we already considered this relids set, don't repeat the work */
619 return;
620
621 /* Identify indexclauses usable with this relids set */
623
625 {
627
628 /* First find applicable simple join clauses */
630 {
632
634 clauseset.indexclauses[indexcol] =
636 }
637
638 /*
639 * Add applicable eclass join clauses. The clauses generated for each
640 * column are redundant (cf generate_implied_equalities_for_column),
641 * so we need at most one. This is the only exception to the general
642 * rule of using all available index clauses.
643 */
645 {
647
649 {
650 clauseset.indexclauses[indexcol] =
652 break;
653 }
654 }
655
656 /* Add restriction clauses */
657 clauseset.indexclauses[indexcol] =
659 rclauseset->indexclauses[indexcol]);
660
663 }
664
665 /* We should have found something, else caller passed silly relids */
667
668 /* Build index path(s) using the collected set of clauses */
670
671 /*
672 * Remember we considered paths for this set of relids.
673 */
675}
676
677/*
678 * eclass_already_used
679 * True if any join clause usable with oldrelids was generated from
680 * the specified equivalence class.
681 */
682static bool
685{
687
689 {
692
693 if (rinfo->parent_ec == parent_ec &&
695 return true;
696 }
697 return false;
698}
699
700
701/*
702 * get_index_paths
703 * Given an index and a set of index clauses for it, construct IndexPaths.
704 *
705 * Plain indexpaths are sent directly to add_path, while potential
706 * bitmap indexpaths are added to *bitindexpaths for later processing.
707 *
708 * This is a fairly simple frontend to build_index_paths(). Its reason for
709 * existence is mainly to handle ScalarArrayOpExpr quals properly. If the
710 * index AM supports them natively, we should just include them in simple
711 * index paths. If not, we should exclude them while building simple index
712 * paths, and then make a separate attempt to include them in bitmap paths.
713 */
714static void
718{
722
723 /*
724 * Build simple index paths using the clauses. Allow ScalarArrayOpExpr
725 * clauses only if the index AM supports them natively.
726 */
728 index, clauses,
729 index->predOK,
730 ST_ANYSCAN,
731 &skip_nonnative_saop);
732
733 /*
734 * Submit all the ones that can form plain IndexScan plans to add_path. (A
735 * plain IndexPath can represent either a plain IndexScan or an
736 * IndexOnlyScan, but for our purposes here that distinction does not
737 * matter. However, some of the indexes might support only bitmap scans,
738 * and those we mustn't submit to add_path here.)
739 *
740 * Also, pick out the ones that are usable as bitmap scans. For that, we
741 * must discard indexes that don't support bitmap scans, and we also are
742 * only interested in paths that have some selectivity; we should discard
743 * anything that was generated solely for ordering purposes.
744 */
746 {
748
751
754 ipath->indexselectivity < 1.0))
756 }
757
758 /*
759 * If there were ScalarArrayOpExpr clauses that the index can't handle
760 * natively, generate bitmap scan paths relying on executor-managed
761 * ScalarArrayOpExpr.
762 */
764 {
766 index, clauses,
767 false,
768 ST_BITMAPSCAN,
769 NULL);
771 }
772}
773
774/*
775 * build_index_paths
776 * Given an index and a set of index clauses for it, construct zero
777 * or more IndexPaths. It also constructs zero or more partial IndexPaths.
778 *
779 * We return a list of paths because (1) this routine checks some cases
780 * that should cause us to not generate any IndexPath, and (2) in some
781 * cases we want to consider both a forward and a backward scan, so as
782 * to obtain both sort orders. Note that the paths are just returned
783 * to the caller and not immediately fed to add_path().
784 *
785 * At top level, useful_predicate should be exactly the index's predOK flag
786 * (ie, true if it has a predicate that was proven from the restriction
787 * clauses). When working on an arm of an OR clause, useful_predicate
788 * should be true if the predicate required the current OR list to be proven.
789 * Note that this routine should never be called at all if the index has an
790 * unprovable predicate.
791 *
792 * scantype indicates whether we want to create plain indexscans, bitmap
793 * indexscans, or both. When it's ST_BITMAPSCAN, we will not consider
794 * index ordering while deciding if a Path is worth generating.
795 *
796 * If skip_nonnative_saop is non-NULL, we ignore ScalarArrayOpExpr clauses
797 * unless the index AM supports them directly, and we set *skip_nonnative_saop
798 * to true if we found any such clauses (caller must initialize the variable
799 * to false). If it's NULL, we do not ignore ScalarArrayOpExpr clauses.
800 *
801 * 'rel' is the index's heap relation
802 * 'index' is the index for which we want to generate paths
803 * 'clauses' is the collection of indexable clauses (IndexClause nodes)
804 * 'useful_predicate' indicates whether the index has a useful predicate
805 * 'scantype' indicates whether we need plain or bitmap scan support
806 * 'skip_nonnative_saop' indicates whether to accept SAOP if index AM doesn't
807 */
814{
818 Relids outer_relids;
827 int indexcol;
828
830
831 /*
832 * Check that index supports the desired scan type(s)
833 */
835 {
839 break;
843 break;
845 /* either or both are OK */
846 break;
847 }
848
849 /*
850 * 1. Combine the per-column IndexClause lists into an overall list.
851 *
852 * In the resulting list, clauses are ordered by index key, so that the
853 * column numbers form a nondecreasing sequence. (This order is depended
854 * on by btree and possibly other places.) The list can be empty, if the
855 * index AM allows that.
856 *
857 * We also build a Relids set showing which outer rels are required by the
858 * selected clauses. Any lateral_relids are included in that, but not
859 * otherwise accounted for.
860 */
864 {
866
868 {
871
874 {
875 /*
876 * Caller asked us to generate IndexPaths that omit any
877 * ScalarArrayOpExpr clauses when the underlying index AM
878 * lacks native support.
879 *
880 * We must omit this clause (and tell caller about it).
881 */
883 continue;
884 }
885
886 /* OK to include this clause */
888 outer_relids = bms_add_members(outer_relids,
889 rinfo->clause_relids);
890 }
891
892 /*
893 * If no clauses match the first index column, check for amoptionalkey
894 * restriction. We can't generate a scan over an index with
895 * amoptionalkey = false unless there's at least one index clause.
896 * (When working on columns after the first, this test cannot fail. It
897 * is always okay for columns after the first to not have any
898 * clauses.)
899 */
902 }
903
904 /* We do not want the index's rel itself listed in outer_relids */
906
907 /* Compute loop_count for cost estimation purposes */
909
910 /*
911 * 2. Compute pathkeys describing index's ordering, if any, then see how
912 * many of them are actually useful for this query. This is not relevant
913 * if we are only trying to build bitmap indexscans.
914 */
919 {
921 ForwardScanDirection);
923 index_pathkeys);
926 }
928 {
929 /*
930 * See if we can generate ordering operators for query_pathkeys or at
931 * least some prefix thereof. Matching to just a prefix of the
932 * query_pathkeys will allow an incremental sort to be considered on
933 * the index's partially sorted results.
934 */
936 &orderbyclauses,
937 &orderbyclausecols);
940 else
943 }
944 else
945 {
949 }
950
951 /*
952 * 3. Check if an index-only scan is possible. If we're not building
953 * plain indexscans, this isn't relevant since bitmap scans don't support
954 * index data retrieval anyway.
955 */
958
959 /*
960 * 4. Generate an indexscan path if there are relevant restriction clauses
961 * in the current clauses, OR the index ordering is potentially useful for
962 * later merging or final output ordering, OR the index has a useful
963 * predicate, OR an index-only scan is possible.
964 */
966 index_only_scan)
967 {
969 index_clauses,
970 orderbyclauses,
971 orderbyclausecols,
972 useful_pathkeys,
973 ForwardScanDirection,
974 index_only_scan,
975 outer_relids,
976 loop_count,
977 false);
979
980 /*
981 * If appropriate, consider parallel index scan. We don't allow
982 * parallel index scan for bitmap index scans.
983 */
987 {
989 index_clauses,
990 orderbyclauses,
991 orderbyclausecols,
992 useful_pathkeys,
993 ForwardScanDirection,
994 index_only_scan,
995 outer_relids,
996 loop_count,
997 true);
998
999 /*
1000 * if, after costing the path, we find that it's not worth using
1001 * parallel workers, just free it.
1002 */
1005 else
1007 }
1008 }
1009
1010 /*
1011 * 5. If the index is ordered, a backwards scan might be interesting.
1012 */
1014 {
1016 BackwardScanDirection);
1018 index_pathkeys);
1020 {
1022 index_clauses,
1023 NIL,
1024 NIL,
1025 useful_pathkeys,
1026 BackwardScanDirection,
1027 index_only_scan,
1028 outer_relids,
1029 loop_count,
1030 false);
1032
1033 /* If appropriate, consider parallel index scan */
1037 {
1039 index_clauses,
1040 NIL,
1041 NIL,
1042 useful_pathkeys,
1043 BackwardScanDirection,
1044 index_only_scan,
1045 outer_relids,
1046 loop_count,
1047 true);
1048
1049 /*
1050 * if, after costing the path, we find that it's not worth
1051 * using parallel workers, just free it.
1052 */
1055 else
1057 }
1058 }
1059 }
1060
1061 return result;
1062}
1063
1064/*
1065 * build_paths_for_OR
1066 * Given a list of restriction clauses from one arm of an OR clause,
1067 * construct all matching IndexPaths for the relation.
1068 *
1069 * Here we must scan all indexes of the relation, since a bitmap OR tree
1070 * can use multiple indexes.
1071 *
1072 * The caller actually supplies two lists of restriction clauses: some
1073 * "current" ones and some "other" ones. Both lists can be used freely
1074 * to match keys of the index, but an index must use at least one of the
1075 * "current" clauses to be considered usable. The motivation for this is
1076 * examples like
1077 * WHERE (x = 42) AND (... OR (y = 52 AND z = 77) OR ....)
1078 * While we are considering the y/z subclause of the OR, we can use "x = 42"
1079 * as one of the available index conditions; but we shouldn't match the
1080 * subclause to any index on x alone, because such a Path would already have
1081 * been generated at the upper level. So we could use an index on x,y,z
1082 * or an index on x,y for the OR subclause, but not an index on just x.
1083 * When dealing with a partial index, a match of the index predicate to
1084 * one of the "current" clauses also makes the index usable.
1085 *
1086 * 'rel' is the relation for which we want to generate index paths
1087 * 'clauses' is the current list of clauses (RestrictInfo nodes)
1088 * 'other_clauses' is the list of additional upper-level clauses
1089 */
1093{
1097
1099 {
1104
1105 /* Ignore index if it doesn't support bitmap scans */
1107 continue;
1108
1109 /*
1110 * Ignore partial indexes that do not match the query. If a partial
1111 * index is marked predOK then we know it's OK. Otherwise, we have to
1112 * test whether the added clauses are sufficient to imply the
1113 * predicate. If so, we can use the index in the current context.
1114 *
1115 * We set useful_predicate to true iff the predicate was proven using
1116 * the current set of clauses. This is needed to prevent matching a
1117 * predOK index to an arm of an OR, which would be a legal but
1118 * pointlessly inefficient plan. (A better plan will be generated by
1119 * just scanning the predOK index alone, no OR.)
1120 */
1123 {
1125 {
1126 /* Usable, but don't set useful_predicate */
1127 }
1128 else
1129 {
1130 /* Form all_clauses if not done already */
1133
1135 continue; /* can't use it at all */
1136
1139 }
1140 }
1141
1142 /*
1143 * Identify the restriction clauses that can match the index.
1144 */
1147
1148 /*
1149 * If no matches so far, and the index predicate isn't useful, we
1150 * don't want it.
1151 */
1153 continue;
1154
1155 /*
1156 * Add "other" restriction clauses to the clauseset.
1157 */
1159
1160 /*
1161 * Construct paths if possible.
1162 */
1165 useful_predicate,
1166 ST_BITMAPSCAN,
1167 NULL);
1169 }
1170
1171 return result;
1172}
1173
1174/*
1175 * Utility structure used to group similar OR-clause arguments in
1176 * group_similar_or_args(). It represents information about the OR-clause
1177 * argument and its matching index key.
1178 */
1179typedef struct
1180{
1181 int indexnum; /* index of the matching index, or -1 if no
1182 * matching index */
1183 int colnum; /* index of the matching column, or -1 if no
1184 * matching index */
1186 * if not an OpExpr */
1188 int argindex; /* index of the clause in the list of
1189 * arguments */
1190 int groupindex; /* value of argindex for the fist clause in
1191 * the group of similar clauses */
1192} OrArgIndexMatch;
1193
1194/*
1195 * Comparison function for OrArgIndexMatch which provides sort order placing
1196 * similar OR-clause arguments together.
1197 */
1198static int
1200{
1203
1205 return -1;
1207 return 1;
1208
1210 return -1;
1212 return 1;
1213
1215 return -1;
1217 return 1;
1218
1220 return -1;
1222 return 1;
1223
1225 return -1;
1227 return 1;
1228
1229 return 0;
1230}
1231
1232/*
1233 * Another comparison function for OrArgIndexMatch. It sorts groups together
1234 * using groupindex. The group items are then sorted by argindex.
1235 */
1236static int
1238{
1241
1243 return -1;
1245 return 1;
1246
1248 return -1;
1250 return 1;
1251
1252 return 0;
1253}
1254
1255/*
1256 * group_similar_or_args
1257 * Transform incoming OR-restrictinfo into a list of sub-restrictinfos,
1258 * each of them containing a subset of similar OR-clause arguments from
1259 * the source rinfo.
1260 *
1261 * Similar OR-clause arguments are of the form "indexkey op constant" having
1262 * the same indexkey, operator, and collation. Constant may comprise either
1263 * Const or Param. It may be employed later, during the
1264 * match_clause_to_indexcol() to transform the whole OR-sub-rinfo to an SAOP
1265 * clause.
1266 *
1267 * Returns the processed list of OR-clause arguments.
1268 */
1271{
1272 int n;
1276 bool matched = false;
1282
1286
1287 /*
1288 * To avoid N^2 behavior, take utility pass along the list of OR-clause
1289 * arguments. For each argument, fill the OrArgIndexMatch structure,
1290 * which will be used to sort these arguments at the next step.
1291 */
1292 i = -1;
1295 {
1298 OpExpr *clause;
1299 Oid opno;
1301 *rightop;
1303 int indexnum;
1304 int colnum;
1305
1306 i++;
1313
1315 continue;
1316
1318
1319 /* Only operator clauses can match */
1321 continue;
1322
1324 opno = clause->opno;
1325
1326 /* Only binary operators can match */
1328 continue;
1329
1330 /*
1331 * Ignore any RelabelType node above the operands. This is needed to
1332 * be able to apply indexscanning in binary-compatible-operator cases.
1333 * Note: we can assume there is at most one RelabelType node;
1334 * eval_const_expressions() will have simplified if more than one.
1335 */
1339
1343
1344 /*
1345 * Check for clauses of the form: (indexkey operator constant) or
1346 * (constant operator indexkey). But we don't know a particular index
1347 * yet. Therefore, we try to distinguish the potential index key and
1348 * constant first, then search for a matching index key among all
1349 * indexes.
1350 */
1354 {
1355 opno = get_commutator(opno);
1356
1358 {
1359 /* commutator doesn't exist, we can't reverse the order */
1360 continue;
1361 }
1363 }
1367 {
1369 }
1370 else
1371 {
1372 continue;
1373 }
1374
1375 /*
1376 * Match non-constant part to the index key. It's possible that a
1377 * single non-constant part matches multiple index keys. It's OK, we
1378 * just stop with first matching index key. Given that this choice is
1379 * determined the same for every clause, we will group similar clauses
1380 * together anyway.
1381 */
1382 indexnum = 0;
1384 {
1386
1387 /*
1388 * Ignore index if it doesn't support bitmap scans or SAOP
1389 * clauses.
1390 */
1392 continue;
1393
1395 {
1397 {
1402 matched = true;
1403 break;
1404 }
1405 }
1406
1407 /*
1408 * Stop looping through the indexes, if we managed to match
1409 * nonConstExpr to any index column.
1410 */
1412 break;
1413 indexnum++;
1414 }
1415 }
1416
1417 /*
1418 * Fast-path check: if no clause is matching to the index column, we can
1419 * just give up at this stage and return the clause list as-is.
1420 */
1421 if (!matched)
1422 {
1425 }
1426
1427 /*
1428 * Sort clauses to make similar clauses go together. But at the same
1429 * time, we would like to change the order of clauses as little as
1430 * possible. To do so, we reorder each group of similar clauses so that
1431 * the first item of the group stays in place, and all the other items are
1432 * moved after it. So, if there are no similar clauses, the order of
1433 * clauses stays the same. When there are some groups, required
1434 * reordering happens while the rest of the clauses remain in their
1435 * places. That is achieved by assigning a 'groupindex' to each clause:
1436 * the number of the first item in the group in the original clause list.
1437 */
1439
1440 /* Assign groupindex to the sorted clauses */
1442 {
1443 /*
1444 * When two clauses are similar and should belong to the same group,
1445 * copy the 'groupindex' from the previous clause. Given we are
1446 * considering clauses in direct order, all the clauses would have a
1447 * 'groupindex' equal to the 'groupindex' of the first clause in the
1448 * group.
1449 */
1456 }
1457
1458 /* Re-sort clauses first by groupindex then by argindex */
1460
1461 /*
1462 * Group similar clauses into single sub-restrictinfo. Side effect: the
1463 * resulting list of restrictions will be sorted by indexnum and colnum.
1464 */
1465 group_start = 0;
1467 {
1468 /* Check if it's a group boundary */
1470 (i == n ||
1476 {
1477 /*
1478 * One clause in group: add it "as is" to the upper-level OR.
1479 */
1481 {
1482 result = lappend(result,
1485 }
1486 else
1487 {
1488 /*
1489 * Two or more clauses in a group: create a nested OR.
1490 */
1495
1497
1498 /* Construct the list of nested OR arguments */
1500 {
1502
1506 else
1508 }
1509
1510 /* Construct the nested OR and wrap it with RestrictInfo */
1512 make_orclause(args),
1513 make_orclause(rargs),
1514 rinfo->is_pushed_down,
1515 rinfo->has_clone,
1516 rinfo->is_clone,
1517 rinfo->pseudoconstant,
1518 rinfo->security_level,
1519 rinfo->required_relids,
1520 rinfo->incompatible_relids,
1521 rinfo->outer_relids);
1523 }
1524
1526 }
1527 }
1529 return result;
1530}
1531
1532/*
1533 * make_bitmap_paths_for_or_group
1534 * Generate bitmap paths for a group of similar OR-clause arguments
1535 * produced by group_similar_or_args().
1536 *
1537 * This function considers two cases: (1) matching a group of clauses to
1538 * the index as a whole, and (2) matching the individual clauses one-by-one.
1539 * (1) typically comprises an optimal solution. If not, (2) typically
1540 * comprises fair alternative.
1541 *
1542 * Ideally, we could consider all arbitrary splits of arguments into
1543 * subgroups, but that could lead to unacceptable computational complexity.
1544 * This is why we only consider two cases of above.
1545 */
1549{
1556 splitcost = 0.0;
1557 Path *bitmapqual;
1559
1560 /*
1561 * First, try to match the whole group to the one index.
1562 */
1565 orargs,
1566 other_clauses);
1568 {
1572 }
1573
1574 /*
1575 * If we manage to find a bitmap scan, which uses the group of OR-clause
1576 * arguments as a whole, we can skip matching OR-clause arguments
1577 * one-by-one as long as there are no other clauses, which can bring more
1578 * efficiency to one-by-one case.
1579 */
1582
1583 /*
1584 * Also try to match all containing clauses one-by-one.
1585 */
1587 {
1589
1591 orargs,
1592 other_clauses);
1593
1595 {
1597 break;
1598 }
1599
1603 }
1604
1605 /*
1606 * Pick the best option.
1607 */
1612 else
1614}
1615
1616
1617/*
1618 * generate_bitmap_or_paths
1619 * Look through the list of clauses to find OR clauses, and generate
1620 * a BitmapOrPath for each one we can handle that way. Return a list
1621 * of the generated BitmapOrPaths.
1622 *
1623 * other_clauses is a list of additional clauses that can be assumed true
1624 * for the purpose of generating indexquals, but are not to be searched for
1625 * ORs. (See build_paths_for_OR() for motivation.)
1626 */
1630{
1634
1635 /*
1636 * We can use both the current and other clauses as context for
1637 * build_paths_for_OR; no need to remove ORs from the lists.
1638 */
1640
1642 {
1644 List *pathlist;
1645 Path *bitmapqual;
1649
1650 /* Ignore RestrictInfos that aren't ORs */
1652 continue;
1653
1654 /*
1655 * We must be able to match at least one index to each of the arms of
1656 * the OR, else we can't use it.
1657 */
1658 pathlist = NIL;
1659
1660 /*
1661 * Group the similar OR-clause arguments into dedicated RestrictInfos,
1662 * because each of those RestrictInfos has a chance to match the index
1663 * as a whole.
1664 */
1666
1668 {
1669 /*
1670 * Some parts of the rinfo were probably grouped. In this case,
1671 * we have a set of sub-rinfos that together are an exact
1672 * duplicate of rinfo. Thus, we need to remove the rinfo from
1673 * other clauses. match_clauses_to_index detects duplicated
1674 * iclauses by comparing pointers to original rinfos that would be
1675 * different. So, we must delete rinfo to avoid de-facto
1676 * duplicated clauses in the index clauses list.
1677 */
1679 }
1680
1682 {
1685
1686 /* OR arguments should be ANDs or sub-RestrictInfos */
1688 {
1690
1692 andargs,
1693 all_clauses);
1694
1695 /* Recurse in case there are sub-ORs */
1698 andargs,
1699 all_clauses));
1700 }
1702 {
1704
1705 /*
1706 * Generate bitmap paths for the group of similar OR-clause
1707 * arguments.
1708 */
1710 rel, ri,
1711 inner_other_clauses);
1712
1714 {
1715 pathlist = NIL;
1716 break;
1717 }
1718 else
1719 {
1721 continue;
1722 }
1723 }
1724 else
1725 {
1728
1730
1732 orargs,
1733 all_clauses);
1734 }
1735
1736 /*
1737 * If nothing matched this arm, we can't do anything with this OR
1738 * clause.
1739 */
1741 {
1742 pathlist = NIL;
1743 break;
1744 }
1745
1746 /*
1747 * OK, pick the most promising AND combination, and add it to
1748 * pathlist.
1749 */
1751 pathlist = lappend(pathlist, bitmapqual);
1752 }
1753
1756
1757 /*
1758 * If we have a match for every arm, then turn them into a
1759 * BitmapOrPath, and add to result list.
1760 */
1762 {
1764 result = lappend(result, bitmapqual);
1765 }
1766 }
1767
1768 return result;
1769}
1770
1771
1772/*
1773 * choose_bitmap_and
1774 * Given a nonempty list of bitmap paths, AND them into one path.
1775 *
1776 * This is a nontrivial decision since we can legally use any subset of the
1777 * given path set. We want to choose a good tradeoff between selectivity
1778 * and cost of computing the bitmap.
1779 *
1780 * The result is either a single one of the inputs, or a BitmapAndPath
1781 * combining multiple inputs.
1782 */
1785{
1793 j;
1794 ListCell *l;
1795
1799
1800 /*
1801 * In theory we should consider every nonempty subset of the given paths.
1802 * In practice that seems like overkill, given the crude nature of the
1803 * estimates, not to mention the possible effects of higher-level AND and
1804 * OR clauses. Moreover, it's completely impractical if there are a large
1805 * number of paths, since the work would grow as O(2^N).
1806 *
1807 * As a heuristic, we first check for paths using exactly the same sets of
1808 * WHERE clauses + index predicate conditions, and reject all but the
1809 * cheapest-to-scan in any such group. This primarily gets rid of indexes
1810 * that include the interesting columns but also irrelevant columns. (In
1811 * situations where the DBA has gone overboard on creating variant
1812 * indexes, this can make for a very large reduction in the number of
1813 * paths considered further.)
1814 *
1815 * We then sort the surviving paths with the cheapest-to-scan first, and
1816 * for each path, consider using that path alone as the basis for a bitmap
1817 * scan. Then we consider bitmap AND scans formed from that path plus
1818 * each subsequent (higher-cost) path, adding on a subsequent path if it
1819 * results in a reduction in the estimated total scan cost. This means we
1820 * consider about O(N^2) rather than O(2^N) path combinations, which is
1821 * quite tolerable, especially given than N is usually reasonably small
1822 * because of the prefiltering step. The cheapest of these is returned.
1823 *
1824 * We will only consider AND combinations in which no two indexes use the
1825 * same WHERE clause. This is a bit of a kluge: it's needed because
1826 * costsize.c and clausesel.c aren't very smart about redundant clauses.
1827 * They will usually double-count the redundant clauses, producing a
1828 * too-small selectivity that makes a redundant AND step look like it
1829 * reduces the total cost. Perhaps someday that code will be smarter and
1830 * we can remove this limitation. (But note that this also defends
1831 * against flat-out duplicate input paths, which can happen because
1832 * match_join_clauses_to_index will find the same OR join clauses that
1833 * extract_restriction_or_clauses has pulled OR restriction clauses out
1834 * of.)
1835 *
1836 * For the same reason, we reject AND combinations in which an index
1837 * predicate clause duplicates another clause. Here we find it necessary
1838 * to be even stricter: we'll reject a partial index if any of its
1839 * predicate clauses are implied by the set of WHERE clauses and predicate
1840 * clauses used so far. This covers cases such as a condition "x = 42"
1841 * used with a plain index, followed by a clauseless scan of a partial
1842 * index "WHERE x >= 40 AND x < 50". The partial index has been accepted
1843 * only because "x = 42" was present, and so allowing it would partially
1844 * double-count selectivity. (We could use predicate_implied_by on
1845 * regular qual clauses too, to have a more intelligent, but much more
1846 * expensive, check for redundancy --- but in most cases simple equality
1847 * seems to suffice.)
1848 */
1849
1850 /*
1851 * Extract clause usage info and detect any paths that use exactly the
1852 * same set of clauses; keep only the cheapest-to-scan of any such groups.
1853 * The surviving paths are put into an array for qsort'ing.
1854 */
1857 npaths = 0;
1858 foreach(l, paths)
1859 {
1861
1863
1864 /* If it's unclassifiable, treat it as distinct from all others */
1866 {
1868 continue;
1869 }
1870
1872 {
1875 break;
1876 }
1878 {
1879 /* duplicate clauseids, keep the cheaper one */
1884
1889 }
1890 else
1891 {
1892 /* not duplicate clauseids, add to array */
1894 }
1895 }
1896
1897 /* If only one surviving path, we're done */
1900
1901 /* Sort the surviving paths by index access cost */
1903 path_usage_comparator);
1904
1905 /*
1906 * For each surviving index, consider it as an "AND group leader", and see
1907 * whether adding on any of the later indexes results in an AND path with
1908 * cheaper total cost than before. Then take the cheapest AND group.
1909 *
1910 * Note: paths that are either clauseless or unclassifiable will have
1911 * empty clauseids, so that they will not be rejected by the clauseids
1912 * filter here, nor will they cause later paths to be rejected by it.
1913 */
1915 {
1919
1925
1927 {
1929
1931 /* Check for redundancy */
1933 continue; /* consider it redundant */
1935 {
1937
1938 /* we check each predicate clause separately */
1940 {
1942
1944 {
1946 break; /* out of inner foreach loop */
1947 }
1948 }
1950 continue;
1951 }
1952 /* tentatively add new path to paths, so we can estimate cost */
1956 {
1957 /* keep new path in paths, update subsidiary variables */
1962 pathinfo->clauseids);
1963 }
1964 else
1965 {
1966 /* reject new path, remove it from paths list */
1968 }
1969 }
1970
1971 /* Keep the cheapest AND-group (or singleton) */
1973 {
1974 bestpaths = paths;
1976 }
1977
1978 /* some easy cleanup (we don't try real hard though) */
1980 }
1981
1985}
1986
1987/* qsort comparator to sort in increasing index access cost order */
1988static int
1990{
1997
2000
2001 /*
2002 * If costs are the same, sort by selectivity.
2003 */
2005 return -1;
2007 return 1;
2008
2010 return -1;
2012 return 1;
2013
2014 return 0;
2015}
2016
2017/*
2018 * Estimate the cost of actually executing a bitmap scan with a single
2019 * index path (which could be a BitmapAnd or BitmapOr node).
2020 */
2023{
2025
2026 /* Set up a dummy BitmapHeapPath */
2029 bpath.path.parent = rel;
2034
2035 /*
2036 * Check the cost of temporary path without considering parallelism.
2037 * Parallel bitmap heap path will be considered at later stage.
2038 */
2039 bpath.path.parallel_workers = 0;
2040
2041 /* Now we can do cost_bitmap_heap_scan */
2043 bpath.path.param_info,
2044 ipath,
2047
2049}
2050
2051/*
2052 * Estimate the cost of actually executing a BitmapAnd scan with the given
2053 * inputs.
2054 */
2057{
2059
2060 /*
2061 * Might as well build a real BitmapAndPath here, as the work is slightly
2062 * too complicated to be worth repeating just to save one palloc.
2063 */
2065
2067}
2068
2069
2070/*
2071 * classify_index_clause_usage
2072 * Construct a PathClauseUsage struct describing the WHERE clauses and
2073 * index predicate clauses used by the given indexscan path.
2074 * We consider two clauses the same if they are equal().
2075 *
2076 * At some point we might want to migrate this info into the Path data
2077 * structure proper, but for the moment it's only needed within
2078 * choose_bitmap_and().
2079 *
2080 * *clauselist is used and expanded as needed to identify all the distinct
2081 * clauses seen across successive calls. Caller must initialize it to NIL
2082 * before first call of a set.
2083 */
2086{
2087 PathClauseUsage *result;
2088 Bitmapset *clauseids;
2090
2092 result->path = path;
2093
2094 /* Recursively find the quals and preds used by the path */
2098
2099 /*
2100 * Some machine-generated queries have outlandish numbers of qual clauses.
2101 * To avoid getting into O(N^2) behavior even in this preliminary
2102 * classification step, we want to limit the number of entries we can
2103 * accumulate in *clauselist. Treat any path with more than 100 quals +
2104 * preds as unclassifiable, which will cause calling code to consider it
2105 * distinct from all other paths.
2106 */
2108 {
2111 return result;
2112 }
2113
2114 /* Build up a bitmapset representing the quals and preds */
2115 clauseids = NULL;
2117 {
2119
2120 clauseids = bms_add_member(clauseids,
2122 }
2124 {
2126
2127 clauseids = bms_add_member(clauseids,
2129 }
2130 result->clauseids = clauseids;
2132
2133 return result;
2134}
2135
2136
2137/*
2138 * find_indexpath_quals
2139 *
2140 * Given the Path structure for a plain or bitmap indexscan, extract lists
2141 * of all the index clauses and index predicate conditions used in the Path.
2142 * These are appended to the initial contents of *quals and *preds (hence
2143 * caller should initialize those to NIL).
2144 *
2145 * Note we are not trying to produce an accurate representation of the AND/OR
2146 * semantics of the Path, but just find out all the base conditions used.
2147 *
2148 * The result lists contain pointers to the expressions used in the Path,
2149 * but all the list cells are freshly built, so it's safe to destructively
2150 * modify the lists (eg, by concat'ing with other lists).
2151 */
2152static void
2154{
2156 {
2158 ListCell *l;
2159
2161 {
2163 }
2164 }
2166 {
2168 ListCell *l;
2169
2171 {
2173 }
2174 }
2176 {
2178 ListCell *l;
2179
2181 {
2183
2185 }
2187 }
2188 else
2190}
2191
2192
2193/*
2194 * find_list_position
2195 * Return the given node's position (counting from 0) in the given
2196 * list of nodes. If it's not equal() to any existing list member,
2197 * add it at the end, and return that position.
2198 */
2199static int
2201{
2204
2205 i = 0;
2207 {
2209
2212 i++;
2213 }
2214
2216
2218}
2219
2220
2221/*
2222 * check_index_only
2223 * Determine whether an index-only scan is possible for this index.
2224 */
2225static bool
2227{
2228 bool result;
2233
2234 /* If we're not allowed to consider index-only scans, give up now */
2236 return false;
2237
2238 /*
2239 * Check that all needed attributes of the relation are available from the
2240 * index.
2241 */
2242
2243 /*
2244 * First, identify all the attributes needed for joins or final output.
2245 * Note: we must look at rel's targetlist, not the attr_needed data,
2246 * because attr_needed isn't computed for inheritance child rels.
2247 */
2249
2250 /*
2251 * Add all the attributes used by restriction clauses; but consider only
2252 * those clauses not implied by the index predicate, since ones that are
2253 * so implied don't need to be checked explicitly in the plan.
2254 *
2255 * Note: attributes used only in index quals would not be needed at
2256 * runtime either, if we are certain that the index is not lossy. However
2257 * it'd be complicated to account for that accurately, and it doesn't
2258 * matter in most cases, since we'd conclude that such attributes are
2259 * available from the index anyway.
2260 */
2262 {
2264
2266 }
2267
2268 /*
2269 * Construct a bitmapset of columns that the index can return back in an
2270 * index-only scan.
2271 */
2273 {
2275
2276 /*
2277 * For the moment, we just ignore index expressions. It might be nice
2278 * to do something with them, later.
2279 */
2280 if (attno == 0)
2281 continue;
2282
2284 index_canreturn_attrs =
2286 attno - FirstLowInvalidHeapAttributeNumber);
2287 }
2288
2289 /* Do we have all the necessary attributes? */
2291
2292 bms_free(attrs_used);
2294
2295 return result;
2296}
2297
2298/*
2299 * get_loop_count
2300 * Choose the loop count estimate to use for costing a parameterized path
2301 * with the given set of outer relids.
2302 *
2303 * Since we produce parameterized paths before we've begun to generate join
2304 * relations, it's impossible to predict exactly how many times a parameterized
2305 * path will be iterated; we don't know the size of the relation that will be
2306 * on the outside of the nestloop. However, we should try to account for
2307 * multiple iterations somehow in costing the path. The heuristic embodied
2308 * here is to use the rowcount of the smallest other base relation needed in
2309 * the join clauses used by the path. (We could alternatively consider the
2310 * largest one, but that seems too optimistic.) This is of course the right
2311 * answer for single-other-relation cases, and it seems like a reasonable
2312 * zero-order approximation for multiway-join cases.
2313 *
2314 * In addition, we check to see if the other side of each join clause is on
2315 * the inside of some semijoin that the current relation is on the outside of.
2316 * If so, the only way that a parameterized path could be used is if the
2317 * semijoin RHS has been unique-ified, so we should use the number of unique
2318 * RHS rows rather than using the relation's raw rowcount.
2319 *
2320 * Note: for this to work, allpaths.c must establish all baserel size
2321 * estimates before it begins to compute paths, or at least before it
2322 * calls create_index_paths().
2323 */
2324static double
2326{
2327 double result;
2329
2330 /* For a non-parameterized path, just return 1.0 quickly */
2332 return 1.0;
2333
2334 result = 0.0;
2335 outer_relid = -1;
2337 {
2339 double rowcount;
2340
2341 /* Paranoia: ignore bogus relid indexes */
2343 continue;
2346 continue;
2348
2349 /* Other relation could be proven empty, if so ignore */
2351 continue;
2352
2353 /* Otherwise, rel's rows estimate should be valid by now */
2355
2356 /* Check to see if rel is on the inside of any semijoins */
2358 cur_relid,
2359 outer_relid,
2360 outer_rel->rows);
2361
2362 /* Remember smallest row count estimate among the outer rels */
2363 if (result == 0.0 || result > rowcount)
2364 result = rowcount;
2365 }
2366 /* Return 1.0 if we found no valid relations (shouldn't happen) */
2367 return (result > 0.0) ? result : 1.0;
2368}
2369
2370/*
2371 * Check to see if outer_relid is on the inside of any semijoin that cur_relid
2372 * is on the outside of. If so, replace rowcount with the estimated number of
2373 * unique rows from the semijoin RHS (assuming that's smaller, which it might
2374 * not be). The estimate is crude but it's the best we can do at this stage
2375 * of the proceedings.
2376 */
2377static double
2381 double rowcount)
2382{
2384
2386 {
2388
2392 {
2393 /* Estimate number of unique-ified rows */
2396
2399 sjinfo->semi_rhs_exprs,
2400 nraw,
2401 NULL,
2402 NULL);
2404 rowcount = nunique;
2405 }
2406 }
2407 return rowcount;
2408}
2409
2410/*
2411 * Make an approximate estimate of the size of a joinrel.
2412 *
2413 * We don't have enough info at this point to get a good estimate, so we
2414 * just multiply the base relation sizes together. Fortunately, this is
2415 * the right answer anyway for the most common case with a single relation
2416 * on the RHS of a semijoin. Also, estimate_num_groups() has only a weak
2417 * dependency on its input_rows argument (it basically uses it as a clamp).
2418 * So we might be able to get a fairly decent end result even with a severe
2419 * overestimate of the RHS's raw size.
2420 */
2421static double
2423{
2424 double rowcount = 1.0;
2425 int relid;
2426
2427 relid = -1;
2429 {
2430 RelOptInfo *rel;
2431
2432 /* Paranoia: ignore bogus relid indexes */
2434 continue;
2435 rel = root->simple_rel_array[relid];
2437 continue;
2439
2440 /* Relation could be proven empty, if so ignore */
2442 continue;
2443
2444 /* Otherwise, rel's rows estimate should be valid by now */
2446
2447 /* Accumulate product */
2448 rowcount *= rel->rows;
2449 }
2450 return rowcount;
2451}
2452
2453
2454/****************************************************************************
2455 * ---- ROUTINES TO CHECK QUERY CLAUSES ----
2456 ****************************************************************************/
2457
2458/*
2459 * match_restriction_clauses_to_index
2460 * Identify restriction clauses for the rel that match the index.
2461 * Matching clauses are added to *clauseset.
2462 */
2463static void
2467{
2468 /* We can ignore clauses that are implied by the index predicate */
2470}
2471
2472/*
2473 * match_join_clauses_to_index
2474 * Identify join clauses for the rel that match the index.
2475 * Matching clauses are added to *clauseset.
2476 * Also, add any potentially usable join OR clauses to *joinorclauses.
2477 * They also might be processed by match_clause_to_index() as a whole.
2478 */
2479static void
2484{
2486
2487 /* Scan the rel's join clauses */
2489 {
2491
2492 /* Check if clause can be moved to this rel */
2494 continue;
2495
2496 /*
2497 * Potentially usable, so see if it matches the index or is an OR. Use
2498 * list_append_unique_ptr() here to avoid possible duplicates when
2499 * processing the same clauses with different indexes.
2500 */
2503
2505 }
2506}
2507
2508/*
2509 * match_eclass_clauses_to_index
2510 * Identify EquivalenceClass join clauses for the rel that match the index.
2511 * Matching clauses are added to *clauseset.
2512 */
2513static void
2516{
2517 int indexcol;
2518
2519 /* No work if rel is not in any such ECs */
2521 return;
2522
2524 {
2526 List *clauses;
2527
2528 /* Generate clauses, skipping any that join to lateral_referencers */
2530 arg.indexcol = indexcol;
2532 index->rel,
2534 &arg,
2535 index->rel->lateral_referencers);
2536
2537 /*
2538 * We have to check whether the results actually do match the index,
2539 * since for non-btree indexes the EC's equality operators might not
2540 * be in the index opclass (cf ec_member_matches_indexcol).
2541 */
2543 }
2544}
2545
2546/*
2547 * match_clauses_to_index
2548 * Perform match_clause_to_index() for each clause in a list.
2549 * Matching clauses are added to *clauseset.
2550 */
2551static void
2553 List *clauses,
2556{
2558
2560 {
2562
2564 }
2565}
2566
2567/*
2568 * match_clause_to_index
2569 * Test whether a qual clause can be used with an index.
2570 *
2571 * If the clause is usable, add an IndexClause entry for it to the appropriate
2572 * list in *clauseset. (*clauseset must be initialized to zeroes before first
2573 * call.)
2574 *
2575 * Note: in some circumstances we may find the same RestrictInfos coming from
2576 * multiple places. Defend against redundant outputs by refusing to add a
2577 * clause twice (pointer equality should be a good enough check for this).
2578 *
2579 * Note: it's possible that a badly-defined index could have multiple matching
2580 * columns. We always select the first match if so; this avoids scenarios
2581 * wherein we get an inflated idea of the index's selectivity by using the
2582 * same clause multiple times with different index columns.
2583 */
2584static void
2586 RestrictInfo *rinfo,
2589{
2590 int indexcol;
2591
2592 /*
2593 * Never match pseudoconstants to indexes. (Normally a match could not
2594 * happen anyway, since a pseudoconstant clause couldn't contain a Var,
2595 * but what if someone builds an expression index on a constant? It's not
2596 * totally unreasonable to do so with a partial index, either.)
2597 */
2598 if (rinfo->pseudoconstant)
2599 return;
2600
2601 /*
2602 * If clause can't be used as an indexqual because it must wait till after
2603 * some lower-security-level restriction clause, reject it.
2604 */
2606 return;
2607
2608 /* OK, check each index key column for a match */
2610 {
2613
2614 /* Ignore duplicates */
2616 {
2618
2620 return;
2621 }
2622
2623 /* OK, try to match the clause to the index column */
2625 rinfo,
2626 indexcol,
2627 index);
2629 {
2630 /* Success, so record it */
2631 clauseset->indexclauses[indexcol] =
2634 return;
2635 }
2636 }
2637}
2638
2639/*
2640 * match_clause_to_indexcol()
2641 * Determine whether a restriction clause matches a column of an index,
2642 * and if so, build an IndexClause node describing the details.
2643 *
2644 * To match an index normally, an operator clause:
2645 *
2646 * (1) must be in the form (indexkey op const) or (const op indexkey);
2647 * and
2648 * (2) must contain an operator which is in the index's operator family
2649 * for this column; and
2650 * (3) must match the collation of the index, if collation is relevant.
2651 *
2652 * Our definition of "const" is exceedingly liberal: we allow anything that
2653 * doesn't involve a volatile function or a Var of the index's relation.
2654 * In particular, Vars belonging to other relations of the query are
2655 * accepted here, since a clause of that form can be used in a
2656 * parameterized indexscan. It's the responsibility of higher code levels
2657 * to manage restriction and join clauses appropriately.
2658 *
2659 * Note: we do need to check for Vars of the index's relation on the
2660 * "const" side of the clause, since clauses like (a.f1 OP (b.f2 OP a.f3))
2661 * are not processable by a parameterized indexscan on a.f1, whereas
2662 * something like (a.f1 OP (b.f2 OP c.f3)) is.
2663 *
2664 * Presently, the executor can only deal with indexquals that have the
2665 * indexkey on the left, so we can only use clauses that have the indexkey
2666 * on the right if we can commute the clause to put the key on the left.
2667 * We handle that by generating an IndexClause with the correctly-commuted
2668 * opclause as a derived indexqual.
2669 *
2670 * If the index has a collation, the clause must have the same collation.
2671 * For collation-less indexes, we assume it doesn't matter; this is
2672 * necessary for cases like "hstore ? text", wherein hstore's operators
2673 * don't care about collation but the clause will get marked with a
2674 * collation anyway because of the text argument. (This logic is
2675 * embodied in the macro IndexCollMatchesExprColl.)
2676 *
2677 * It is also possible to match RowCompareExpr clauses to indexes (but
2678 * currently, only btree indexes handle this).
2679 *
2680 * It is also possible to match ScalarArrayOpExpr clauses to indexes, when
2681 * the clause is of the form "indexkey op ANY (arrayconst)".
2682 *
2683 * It is also possible to match a list of OR clauses if it might be
2684 * transformed into a single ScalarArrayOpExpr clause. On success,
2685 * the returning index clause will contain a transformed clause.
2686 *
2687 * For boolean indexes, it is also possible to match the clause directly
2688 * to the indexkey; or perhaps the clause is (NOT indexkey).
2689 *
2690 * And, last but not least, some operators and functions can be processed
2691 * to derive (typically lossy) indexquals from a clause that isn't in
2692 * itself indexable. If we see that any operand of an OpExpr or FuncExpr
2693 * matches the index key, and the function has a planner support function
2694 * attached to it, we'll invoke the support function to see if such an
2695 * indexqual can be built.
2696 *
2697 * 'rinfo' is the clause to be tested (as a RestrictInfo node).
2698 * 'indexcol' is a column number of 'index' (counting from 0).
2699 * 'index' is the index of interest.
2700 *
2701 * Returns an IndexClause if the clause can be used with this index key,
2702 * or NULL if not.
2703 *
2704 * NOTE: This routine always returns NULL if the clause is an AND clause.
2705 * Higher-level routines deal with OR and AND clauses. OR clause can be
2706 * matched as a whole by match_orclause_to_indexcol() though.
2707 */
2710 RestrictInfo *rinfo,
2711 int indexcol,
2713{
2716 Oid opfamily;
2717
2719
2720 /*
2721 * Historically this code has coped with NULL clauses. That's probably
2722 * not possible anymore, but we might as well continue to cope.
2723 */
2726
2727 /* First check for boolean-index cases. */
2728 opfamily = index->opfamily[indexcol];
2730 {
2734 }
2735
2736 /*
2737 * Clause must be an opclause, funcclause, ScalarArrayOpExpr,
2738 * RowCompareExpr, or OR-clause that could be converted to SAOP. Or, if
2739 * the index supports it, we can handle IS NULL/NOT NULL clauses.
2740 */
2742 {
2744 }
2746 {
2748 }
2750 {
2752 }
2754 {
2756 }
2758 {
2760 }
2762 {
2764
2767 {
2769 iclause->rinfo = rinfo;
2772 iclause->indexcol = indexcol;
2775 }
2776 }
2777
2779}
2780
2781/*
2782 * IsBooleanOpfamily
2783 * Detect whether an opfamily supports boolean equality as an operator.
2784 *
2785 * If the opfamily OID is in the range of built-in objects, we can rely
2786 * on hard-wired knowledge of which built-in opfamilies support this.
2787 * For extension opfamilies, there's no choice but to do a catcache lookup.
2788 */
2789static bool
2791{
2794 else
2796}
2797
2798/*
2799 * match_boolean_index_clause
2800 * Recognize restriction clauses that can be matched to a boolean index.
2801 *
2802 * The idea here is that, for an index on a boolean column that supports the
2803 * BooleanEqualOperator, we can transform a plain reference to the indexkey
2804 * into "indexkey = true", or "NOT indexkey" into "indexkey = false", etc,
2805 * so as to make the expression indexable using the index's "=" operator.
2806 * Since Postgres 8.1, we must do this because constant simplification does
2807 * the reverse transformation; without this code there'd be no way to use
2808 * such an index at all.
2809 *
2810 * This should be called only when IsBooleanOpfamily() recognizes the
2811 * index's operator family. We check to see if the clause matches the
2812 * index's key, and if so, build a suitable IndexClause.
2813 */
2816 RestrictInfo *rinfo,
2817 int indexcol,
2819{
2822
2823 /* Direct match? */
2825 {
2826 /* convert to indexkey = TRUE */
2828 (Expr *) clause,
2831 }
2832 /* NOT clause? */
2834 {
2836
2838 {
2839 /* convert to indexkey = FALSE */
2844 }
2845 }
2846
2847 /*
2848 * Since we only consider clauses at top level of WHERE, we can convert
2849 * indexkey IS TRUE and indexkey IS FALSE to index searches as well. The
2850 * different meaning for NULL isn't important.
2851 */
2853 {
2856
2859 {
2860 /* convert to indexkey = TRUE */
2865 }
2868 {
2869 /* convert to indexkey = FALSE */
2874 }
2875 }
2876
2877 /*
2878 * If we successfully made an operator clause from the given qual, we must
2879 * wrap it in an IndexClause. It's not lossy.
2880 */
2881 if (op)
2882 {
2884
2885 iclause->rinfo = rinfo;
2888 iclause->indexcol = indexcol;
2891 }
2892
2894}
2895
2896/*
2897 * match_opclause_to_indexcol()
2898 * Handles the OpExpr case for match_clause_to_indexcol(),
2899 * which see for comments.
2900 */
2903 RestrictInfo *rinfo,
2904 int indexcol,
2906{
2910 *rightop;
2914 Oid opfamily;
2916
2917 /*
2918 * Only binary operators need apply. (In theory, a planner support
2919 * function could do something with a unary operator, but it seems
2920 * unlikely to be worth the cycles to check.)
2921 */
2924
2927 expr_op = clause->opno;
2928 expr_coll = clause->inputcollid;
2929
2931 opfamily = index->opfamily[indexcol];
2933
2934 /*
2935 * Check for clauses of the form: (indexkey operator constant) or
2936 * (constant operator indexkey). See match_clause_to_indexcol's notes
2937 * about const-ness.
2938 *
2939 * Note that we don't ask the support function about clauses that don't
2940 * have one of these forms. Again, in principle it might be possible to
2941 * do something, but it seems unlikely to be worth the cycles to check.
2942 */
2946 {
2949 {
2951 iclause->rinfo = rinfo;
2954 iclause->indexcol = indexcol;
2957 }
2958
2959 /*
2960 * If we didn't find a member of the index's opfamily, try the support
2961 * function for the operator's underlying function.
2962 */
2965 rinfo,
2966 clause->opfuncid,
2967 0, /* indexarg on left */
2968 indexcol,
2969 index);
2970 }
2971
2975 {
2977 {
2979
2982 {
2984
2985 /* Build a commuted OpExpr and RestrictInfo */
2987
2988 /* Make an IndexClause showing that as a derived qual */
2990 iclause->rinfo = rinfo;
2993 iclause->indexcol = indexcol;
2996 }
2997 }
2998
2999 /*
3000 * If we didn't find a member of the index's opfamily, try the support
3001 * function for the operator's underlying function.
3002 */
3005 rinfo,
3006 clause->opfuncid,
3007 1, /* indexarg on right */
3008 indexcol,
3009 index);
3010 }
3011
3013}
3014
3015/*
3016 * match_funcclause_to_indexcol()
3017 * Handles the FuncExpr case for match_clause_to_indexcol(),
3018 * which see for comments.
3019 */
3022 RestrictInfo *rinfo,
3023 int indexcol,
3025{
3027 int indexarg;
3029
3030 /*
3031 * We have no built-in intelligence about function clauses, but if there's
3032 * a planner support function, it might be able to do something. But, to
3033 * cut down on wasted planning cycles, only call the support function if
3034 * at least one argument matches the target index column.
3035 *
3036 * Note that we don't insist on the other arguments being pseudoconstants;
3037 * the support function has to check that. This is to allow cases where
3038 * only some of the other arguments need to be included in the indexqual.
3039 */
3040 indexarg = 0;
3042 {
3044
3046 {
3048 rinfo,
3049 clause->funcid,
3050 indexarg,
3051 indexcol,
3052 index);
3053 }
3054
3055 indexarg++;
3056 }
3057
3059}
3060
3061/*
3062 * get_index_clause_from_support()
3063 * If the function has a planner support function, try to construct
3064 * an IndexClause using indexquals created by the support function.
3065 */
3068 RestrictInfo *rinfo,
3069 Oid funcid,
3070 int indexarg,
3071 int indexcol,
3073{
3077
3080
3083 req.funcid = funcid;
3085 req.indexarg = indexarg;
3087 req.indexcol = indexcol;
3090
3092
3096
3098 {
3102
3103 /*
3104 * The support function API says it should just give back bare
3105 * clauses, so here we must wrap each one in a RestrictInfo.
3106 */
3108 {
3110
3111 indexquals = lappend(indexquals,
3113 }
3114
3115 iclause->rinfo = rinfo;
3116 iclause->indexquals = indexquals;
3118 iclause->indexcol = indexcol;
3120
3122 }
3123
3125}
3126
3127/*
3128 * match_saopclause_to_indexcol()
3129 * Handles the ScalarArrayOpExpr case for match_clause_to_indexcol(),
3130 * which see for comments.
3131 */
3134 RestrictInfo *rinfo,
3135 int indexcol,
3137{
3140 *rightop;
3145 Oid opfamily;
3147
3148 /* We only accept ANY clauses, not ALL */
3149 if (!saop->useOr)
3154 expr_op = saop->opno;
3155 expr_coll = saop->inputcollid;
3156
3158 opfamily = index->opfamily[indexcol];
3160
3161 /*
3162 * We must have indexkey on the left and a pseudo-constant array argument.
3163 */
3167 {
3170 {
3172
3173 iclause->rinfo = rinfo;
3176 iclause->indexcol = indexcol;
3179 }
3180
3181 /*
3182 * We do not currently ask support functions about ScalarArrayOpExprs,
3183 * though in principle we could.
3184 */
3185 }
3186
3188}
3189
3190/*
3191 * match_rowcompare_to_indexcol()
3192 * Handles the RowCompareExpr case for match_clause_to_indexcol(),
3193 * which see for comments.
3194 *
3195 * In this routine we check whether the first column of the row comparison
3196 * matches the target index column. This is sufficient to guarantee that some
3197 * index condition can be constructed from the RowCompareExpr --- the rest
3198 * is handled by expand_indexqual_rowcompare().
3199 */
3202 RestrictInfo *rinfo,
3203 int indexcol,
3205{
3208 Oid opfamily;
3211 *rightop;
3215
3216 /* Forget it if we're not dealing with a btree index */
3219
3221 opfamily = index->opfamily[indexcol];
3223
3224 /*
3225 * We could do the matching on the basis of insisting that the opfamily
3226 * shown in the RowCompareExpr be the same as the index column's opfamily,
3227 * but that could fail in the presence of reverse-sort opfamilies: it'd be
3228 * a matter of chance whether RowCompareExpr had picked the forward or
3229 * reverse-sort family. So look only at the operator, and match if it is
3230 * a member of the index's opfamily (after commutation, if the indexkey is
3231 * on the right). We'll worry later about whether any additional
3232 * operators are matchable to the index.
3233 */
3238
3239 /* Collations must match, if relevant */
3242
3243 /*
3244 * These syntactic tests are the same as in match_opclause_to_indexcol()
3245 */
3249 {
3250 /* OK, indexkey is on left */
3252 }
3256 {
3257 /* indexkey is on right, so commute the operator */
3262 }
3263 else
3265
3266 /* We're good if the operator is the right type of opfamily member */
3268 {
3274 rinfo,
3275 indexcol,
3276 index,
3277 expr_op,
3278 var_on_left);
3279 }
3280
3282}
3283
3284/*
3285 * match_orclause_to_indexcol()
3286 * Handles the OR-expr case for match_clause_to_indexcol() in the case
3287 * when it could be transformed to ScalarArrayOpExpr.
3288 *
3289 * In this routine, we attempt to transform a list of OR-clause args into a
3290 * single SAOP expression matching the target index column. On success,
3291 * return an IndexClause containing the transformed expression.
3292 * Return NULL if the transformation fails.
3293 */
3296 RestrictInfo *rinfo,
3297 int indexcol,
3299{
3313
3314 /* Forget it if index doesn't support SAOP clauses */
3317
3318 /*
3319 * Try to convert a list of OR-clauses to a single SAOP expression. Each
3320 * OR entry must be in the form: (indexkey operator constant) or (constant
3321 * operator indexkey). Operators of all the entries must match. On
3322 * discovery of anything unsupported, we give up by breaking out of the
3323 * loop immediately and returning NULL.
3324 */
3326 {
3329 Oid opno;
3331 *rightop;
3333
3334 /* If it's not a RestrictInfo (i.e. it's a sub-AND), we can't use it */
3336 break;
3337
3338 /* Only operator clauses can match */
3340 break;
3341
3343 opno = subClause->opno;
3344
3345 /* Only binary operators can match */
3347 break;
3348
3349 /*
3350 * Check for clauses of the form: (indexkey operator constant) or
3351 * (constant operator indexkey). These tests should agree with
3352 * match_opclause_to_indexcol.
3353 */
3359 {
3362 }
3366 {
3367 opno = get_commutator(opno);
3369 {
3370 /* commutator doesn't exist, we can't reverse the order */
3371 break;
3372 }
3375 }
3376 else
3377 {
3378 break;
3379 }
3380
3381 /*
3382 * Save information about the operator, type, and collation for the
3383 * first matching qual. Then, check that subsequent quals match the
3384 * first.
3385 */
3387 {
3388 matchOpno = opno;
3391 inputcollid = subClause->inputcollid;
3392
3393 /*
3394 * Check that the operator is presented in the opfamily and that
3395 * the expression collation matches the index collation. Also,
3396 * there must be an array type to construct an array later.
3397 */
3399 inputcollid) ||
3402 break;
3403
3404 /*
3405 * Disallow if either type is RECORD, mainly because we can't be
3406 * positive that all the RHS expressions are the same record type.
3407 */
3409 break;
3410
3412 }
3413 else
3414 {
3416 inputcollid != subClause->inputcollid ||
3418 break;
3419 }
3420
3421 /*
3422 * The righthand inputs don't necessarily have to be plain Consts, but
3423 * make_SAOP_expr needs to know if any are not.
3424 */
3427
3429 }
3430
3431 /*
3432 * Handle failed conversion from breaking out of the loop because of an
3433 * unsupported qual. Also check that we have an indexExpr, just in case
3434 * the OR list was somehow empty (it shouldn't be). Return NULL to
3435 * indicate the conversion failed.
3436 */
3438 {
3441 }
3442
3443 /*
3444 * Build the new SAOP node. We use the indexExpr from the last OR arm;
3445 * since all the arms passed match_index_to_operand, it shouldn't matter
3446 * which one we use. But using "inputcollid" twice is a bit of a cheat:
3447 * we might end up with an array Const node that is labeled with a
3448 * collation despite its elements being of a noncollatable type. But
3449 * nothing is likely to complain about that, so we don't bother being more
3450 * accurate.
3451 */
3455
3456 /*
3457 * Finally, build an IndexClause based on the SAOP node. It's not lossy.
3458 */
3460 iclause->rinfo = rinfo;
3464 iclause->indexcol = indexcol;
3467}
3468
3469/*
3470 * expand_indexqual_rowcompare --- expand a single indexqual condition
3471 * that is a RowCompareExpr
3472 *
3473 * It's already known that the first column of the row comparison matches
3474 * the specified column of the index. We can use additional columns of the
3475 * row comparison as index qualifications, so long as they match the index
3476 * in the "same direction", ie, the indexkeys are all on the same side of the
3477 * clause and the operators are all the same-type members of the opfamilies.
3478 *
3479 * If all the columns of the RowCompareExpr match in this way, we just use it
3480 * as-is, except for possibly commuting it to put the indexkeys on the left.
3481 *
3482 * Otherwise, we build a shortened RowCompareExpr (if more than one
3483 * column matches) or a simple OpExpr (if the first-column match is all
3484 * there is). In these cases the modified clause is always "<=" or ">="
3485 * even when the original was "<" or ">" --- this is necessary to match all
3486 * the rows that could match the original. (We are building a lossy version
3487 * of the row comparison when we do this, so we set lossy = true.)
3488 *
3489 * Note: this is really just the last half of match_rowcompare_to_indexcol,
3490 * but we split it out for comprehensibility.
3491 */
3494 RestrictInfo *rinfo,
3495 int indexcol,
3499{
3502 int op_strategy;
3513
3514 iclause->rinfo = rinfo;
3515 iclause->indexcol = indexcol;
3516
3518 {
3519 var_args = clause->largs;
3520 non_var_args = clause->rargs;
3521 }
3522 else
3523 {
3524 var_args = clause->rargs;
3525 non_var_args = clause->largs;
3526 }
3527
3529 &op_strategy,
3530 &op_lefttype,
3531 &op_righttype);
3532
3533 /* Initialize returned list of which index columns are used */
3535
3536 /* Build lists of ops, opfamilies and operator datatypes in case needed */
3541
3542 /*
3543 * See how many of the remaining columns match some index column in the
3544 * same way. As in match_clause_to_indexcol(), the "other" side of any
3545 * potential index condition is OK as long as it doesn't use Vars from the
3546 * indexed relation.
3547 */
3548 matching_cols = 1;
3549
3551 {
3555
3558 {
3559 /* indexkey is on right, so commute the operator */
3562 break; /* operator is not usable */
3563 }
3565 break; /* no good, Var on wrong side */
3567 break; /* no good, volatile comparison value */
3568
3569 /*
3570 * The Var side can match any key column of the index.
3571 */
3573 {
3578 list_nth_oid(clause->inputcollids,
3579 matching_cols)))
3580 break;
3581 }
3583 break; /* no match found */
3584
3585 /* Add column number to returned list */
3587
3588 /* Add operator info to lists */
3590 &op_strategy,
3591 &op_lefttype,
3592 &op_righttype);
3597
3598 /* This column matches, keep scanning */
3599 matching_cols++;
3600 }
3601
3602 /* Result is non-lossy if all columns are usable as index quals */
3604
3605 /*
3606 * We can use rinfo->clause as-is if we have var on left and it's all
3607 * usable as index quals.
3608 */
3611 else
3612 {
3613 /*
3614 * We have to generate a modified rowcompare (possibly just one
3615 * OpExpr). The painful part of this is changing < to <= or > to >=,
3616 * so deal with that first.
3617 */
3619 {
3620 /* very easy, just use the commuted operators */
3622 }
3624 op_strategy == BTGreaterEqualStrategyNumber)
3625 {
3626 /* easy, just use the same (possibly commuted) operators */
3628 }
3629 else
3630 {
3634
3636 op_strategy = BTLessEqualStrategyNumber;
3638 op_strategy = BTGreaterEqualStrategyNumber;
3639 else
3645 {
3649
3651 op_strategy);
3654 op_strategy, lefttype, righttype, opfam);
3656 }
3657 }
3658
3659 /* If we have more than one matching col, create a subset rowcompare */
3661 {
3663
3665 rc->opnos = new_ops;
3666 rc->opfamilies = list_copy_head(clause->opfamilies,
3667 matching_cols);
3668 rc->inputcollids = list_copy_head(clause->inputcollids,
3669 matching_cols);
3673 (Expr *) rc));
3674 }
3675 else
3676 {
3677 Expr *op;
3678
3679 /* We don't report an index column list in this case */
3681
3685 InvalidOid,
3686 linitial_oid(clause->inputcollids));
3688 }
3689 }
3690
3692}
3693
3694
3695/****************************************************************************
3696 * ---- ROUTINES TO CHECK ORDERING OPERATORS ----
3697 ****************************************************************************/
3698
3699/*
3700 * match_pathkeys_to_index
3701 * For the given 'index' and 'pathkeys', output a list of suitable ORDER
3702 * BY expressions, each of the form "indexedcol operator pseudoconstant",
3703 * along with an integer list of the index column numbers (zero based)
3704 * that each clause would be used with.
3705 *
3706 * This attempts to find an ORDER BY and index column number for all items in
3707 * the pathkey list, however, if we're unable to match any given pathkey to an
3708 * index column, we return just the ones matched by the function so far. This
3709 * allows callers who are interested in partial matches to get them. Callers
3710 * can determine a partial match vs a full match by checking the outputted
3711 * list lengths. A full match will have one item in the output lists for each
3712 * item in the given 'pathkeys' list.
3713 */
3714static void
3718{
3720
3723
3724 /* Only indexes with the amcanorderbyop property are interesting here */
3726 return;
3727
3729 {
3731 bool found = false;
3733 EquivalenceMember *member;
3734
3735
3736 /* Pathkey must request default sort order for the target opfamily */
3738 return;
3739
3740 /* If eclass is volatile, no hope of using an indexscan */
3742 return;
3743
3744 /*
3745 * Try to match eclass member expression(s) to index. Note that child
3746 * EC members are considered, but only when they belong to the target
3747 * relation. (Unlike regular members, the same expression could be a
3748 * child member of more than one EC. Therefore, the same index could
3749 * be considered to match more than one pathkey list, which is OK
3750 * here. See also get_eclass_for_sort_expr.)
3751 */
3753 index->rel->relids);
3755 {
3756 int indexcol;
3757
3758 /* No possibility of match if it references other relations */
3760 continue;
3761
3762 /*
3763 * We allow any column of the index to match each pathkey; they
3764 * don't have to match left-to-right as you might expect. This is
3765 * correct for GiST, and it doesn't matter for SP-GiST because
3766 * that doesn't handle multiple columns anyway, and no other
3767 * existing AMs support amcanorderbyop. We might need different
3768 * logic in future for other implementations.
3769 */
3771 {
3772 Expr *expr;
3773
3775 indexcol,
3776 member->em_expr,
3777 pathkey->pk_opfamily);
3778 if (expr)
3779 {
3782 found = true;
3783 break;
3784 }
3785 }
3786
3787 if (found) /* don't want to look at remaining members */
3788 break;
3789 }
3790
3791 /*
3792 * Return the matches found so far when this pathkey couldn't be
3793 * matched to the index.
3794 */
3795 if (!found)
3796 return;
3797 }
3798}
3799
3800/*
3801 * match_clause_to_ordering_op
3802 * Determines whether an ordering operator expression matches an
3803 * index column.
3804 *
3805 * This is similar to, but simpler than, match_clause_to_indexcol.
3806 * We only care about simple OpExpr cases. The input is a bare
3807 * expression that is being ordered by, which must be of the form
3808 * (indexkey op const) or (const op indexkey) where op is an ordering
3809 * operator for the column's opfamily.
3810 *
3811 * 'index' is the index of interest.
3812 * 'indexcol' is a column number of 'index' (counting from 0).
3813 * 'clause' is the ordering expression to be tested.
3814 * 'pk_opfamily' is the btree opfamily describing the required sort order.
3815 *
3816 * Note that we currently do not consider the collation of the ordering
3817 * operator's result. In practical cases the result type will be numeric
3818 * and thus have no collation, and it's not very clear what to match to
3819 * if it did have a collation. The index's collation should match the
3820 * ordering operator's input collation, not its result.
3821 *
3822 * If successful, return 'clause' as-is if the indexkey is on the left,
3823 * otherwise a commuted copy of 'clause'. If no match, return NULL.
3824 */
3827 int indexcol,
3828 Expr *clause,
3829 Oid pk_opfamily)
3830{
3831 Oid opfamily;
3834 *rightop;
3837 Oid sortfamily;
3839
3841
3842 opfamily = index->opfamily[indexcol];
3844
3845 /*
3846 * Clause must be a binary opclause.
3847 */
3856
3857 /*
3858 * We can forget the whole thing right away if wrong collation.
3859 */
3862
3863 /*
3864 * Check for clauses of the form: (indexkey operator constant) or
3865 * (constant operator indexkey).
3866 */
3870 {
3872 }
3876 {
3877 /* Might match, but we need a commuted operator */
3882 }
3883 else
3885
3886 /*
3887 * Is the (commuted) operator an ordering operator for the opfamily? And
3888 * if so, does it yield the right sorting semantics?
3889 */
3891 if (sortfamily != pk_opfamily)
3893
3894 /* We have a match. Return clause or a commuted version thereof. */
3896 {
3898
3899 /* flat-copy all the fields of clause */
3901
3902 /* commute it */
3906
3908 }
3909
3910 return clause;
3911}
3912
3913
3914/****************************************************************************
3915 * ---- ROUTINES TO DO PARTIAL INDEX PREDICATE TESTS ----
3916 ****************************************************************************/
3917
3918/*
3919 * check_index_predicates
3920 * Set the predicate-derived IndexOptInfo fields for each index
3921 * of the specified relation.
3922 *
3923 * predOK is set true if the index is partial and its predicate is satisfied
3924 * for this query, ie the query's WHERE clauses imply the predicate.
3925 *
3926 * indrestrictinfo is set to the relation's baserestrictinfo list less any
3927 * conditions that are implied by the index's predicate. (Obviously, for a
3928 * non-partial index, this is the same as baserestrictinfo.) Such conditions
3929 * can be dropped from the plan when using the index, in certain cases.
3930 *
3931 * At one time it was possible for this to get re-run after adding more
3932 * restrictions to the rel, thus possibly letting us prove more indexes OK.
3933 * That doesn't happen any more (at least not in the core code's usage),
3934 * but this code still supports it in case extensions want to mess with the
3935 * baserestrictinfo list. We assume that adding more restrictions can't make
3936 * an index not predOK. We must recompute indrestrictinfo each time, though,
3937 * to make sure any newly-added restrictions get into it if needed.
3938 */
3939void
3941{
3947
3948 /* Indexes are available only on base or "other" member relations. */
3950
3951 /*
3952 * Initialize the indrestrictinfo lists to be identical to
3953 * baserestrictinfo, and check whether there are any partial indexes. If
3954 * not, this is all we need to do.
3955 */
3958 {
3960
3964 }
3966 return;
3967
3968 /*
3969 * Construct a list of clauses that we can assume true for the purpose of
3970 * proving the index(es) usable. Restriction clauses for the rel are
3971 * always usable, and so are any join clauses that are "movable to" this
3972 * rel. Also, we can consider any EC-derivable join clauses (which must
3973 * be "movable to" this rel, by definition).
3974 */
3976
3977 /* Scan the rel's join clauses */
3979 {
3981
3982 /* Check if clause can be moved to this rel */
3984 continue;
3985
3987 }
3988
3989 /*
3990 * Add on any equivalence-derivable join clauses. Computing the correct
3991 * relid sets for generate_join_implied_equalities is slightly tricky
3992 * because the rel could be a child rel rather than a true baserel, and in
3993 * that case we must subtract its parents' relid(s) from all_query_rels.
3994 * Additionally, we mustn't consider clauses that are only computable
3995 * after outer joins that can null the rel.
3996 */
4000 else
4003
4005 clauselist =
4009 otherrels),
4010 otherrels,
4011 rel,
4012 NULL));
4013
4014 /*
4015 * Normally we remove quals that are implied by a partial index's
4016 * predicate from indrestrictinfo, indicating that they need not be
4017 * checked explicitly by an indexscan plan using this index. However, if
4018 * the rel is a target relation of UPDATE/DELETE/MERGE/SELECT FOR UPDATE,
4019 * we cannot remove such quals from the plan, because they need to be in
4020 * the plan so that they will be properly rechecked by EvalPlanQual
4021 * testing. Some day we might want to remove such quals from the main
4022 * plan anyway and pass them through to EvalPlanQual via a side channel;
4023 * but for now, we just don't remove implied quals at all for target
4024 * relations.
4025 */
4028
4029 /*
4030 * Now try to prove each index predicate true, and compute the
4031 * indrestrictinfo lists for partial indexes. Note that we compute the
4032 * indrestrictinfo list even for non-predOK indexes; this might seem
4033 * wasteful, but we may be able to use such indexes in OR clauses, cf
4034 * generate_bitmap_or_paths().
4035 */
4037 {
4040
4042 continue; /* ignore non-partial indexes here */
4043
4046 false);
4047
4048 /* If rel is an update target, leave indrestrictinfo as set above */
4050 continue;
4051
4052 /*
4053 * If index is !amoptionalkey, also leave indrestrictinfo as set
4054 * above. Otherwise we risk removing all quals for the first index
4055 * key and then not being able to generate an indexscan at all. It
4056 * would be better to be more selective, but we've not yet identified
4057 * which if any of the quals match the first index key.
4058 */
4060 continue;
4061
4062 /* Else compute indrestrictinfo as the non-implied quals */
4065 {
4067
4068 /* predicate_implied_by() assumes first arg is immutable */
4073 }
4074 }
4075}
4076
4077/****************************************************************************
4078 * ---- ROUTINES TO CHECK EXTERNALLY-VISIBLE CONDITIONS ----
4079 ****************************************************************************/
4080
4081/*
4082 * ec_member_matches_indexcol
4083 * Test whether an EquivalenceClass member matches an index column.
4084 *
4085 * This is a callback for use by generate_implied_equalities_for_column.
4086 */
4087static bool
4091{
4096
4098
4101
4102 /*
4103 * If it's a btree index, we can reject it if its opfamily isn't
4104 * compatible with the EC, since no clause generated from the EC could be
4105 * used with the index. For non-btree indexes, we can't easily tell
4106 * whether clauses generated from the EC could be used with the index, so
4107 * don't check the opfamily. This might mean we return "true" for a
4108 * useless EC, so we have to recheck the results of
4109 * generate_implied_equalities_for_column; see
4110 * match_eclass_clauses_to_index.
4111 */
4114 return false;
4115
4116 /* We insist on collation match for all index types, though */
4118 return false;
4119
4121}
4122
4123/*
4124 * relation_has_unique_index_for
4125 * Determine whether the relation provably has at most one row satisfying
4126 * a set of equality conditions, because the conditions constrain all
4127 * columns of some unique index.
4128 *
4129 * The conditions are provided as a list of RestrictInfo nodes, where the
4130 * caller has already determined that each condition is a mergejoinable
4131 * equality with an expression in this relation on one side, and an
4132 * expression not involving this relation on the other. The transient
4133 * outer_is_left flag is used to identify which side we should look at:
4134 * left side if outer_is_left is false, right side if it is true.
4135 *
4136 * The caller need only supply equality conditions arising from joins;
4137 * this routine automatically adds in any usable baserestrictinfo clauses.
4138 * (Note that the passed-in restrictlist will be destructively modified!)
4139 *
4140 * If extra_clauses isn't NULL, return baserestrictinfo clauses which were used
4141 * to derive uniqueness.
4142 */
4143bool
4146{
4148
4149 /* Short-circuit if no indexes... */
4151 return false;
4152
4153 /*
4154 * Examine the rel's restriction clauses for usable var = const clauses
4155 * that we can add to the restrictlist.
4156 */
4158 {
4160
4161 /*
4162 * Note: can_join won't be set for a restriction clause, but
4163 * mergeopfamilies will be if it has a mergejoinable operator and
4164 * doesn't contain volatile functions.
4165 */
4167 continue; /* not mergejoinable */
4168
4169 /*
4170 * The clause certainly doesn't refer to anything but the given rel.
4171 * If either side is pseudoconstant then we can use it.
4172 */
4174 {
4175 /* righthand side is inner */
4177 }
4179 {
4180 /* lefthand side is inner */
4182 }
4183 else
4184 continue;
4185
4186 /* OK, add to list */
4188 }
4189
4190 /* Short-circuit the easy case */
4192 return false;
4193
4194 /* Examine each index of the relation ... */
4196 {
4200
4201 /*
4202 * If the index is not unique, or not immediately enforced, or if it's
4203 * a partial index, it's useless here. We're unable to make use of
4204 * predOK partial unique indexes due to the fact that
4205 * check_index_predicates() also makes use of join predicates to
4206 * determine if the partial index is usable. Here we need proofs that
4207 * hold true before any joins are evaluated.
4208 */
4210 continue;
4211
4212 /*
4213 * Try to find each index column in the list of conditions. This is
4214 * O(N^2) or worse, but we expect all the lists to be short.
4215 */
4217 {
4219
4221 {
4223 Node *rexpr;
4224
4225 /*
4226 * The condition's equality operator must be a member of the
4227 * index opfamily, else it is not asserting the right kind of
4228 * equality behavior for this index. We check this first
4229 * since it's probably cheaper than match_index_to_operand().
4230 */
4232 continue;
4233
4234 /*
4235 * XXX at some point we may need to check collations here too.
4236 * For the moment we assume all collations reduce to the same
4237 * notion of equality.
4238 */
4239
4240 /* OK, see if the condition operand matches the index key */
4241 if (rinfo->outer_is_left)
4243 else
4245
4247 {
4249 {
4252
4253 /*
4254 * Add filter clause into a list allowing caller to
4255 * know if uniqueness have made not only by join
4256 * clauses.
4257 */
4259 bms_is_empty(rinfo->right_relids));
4260 if (extra_clauses)
4261 exprs = lappend(exprs, rinfo);
4263 }
4264
4265 break; /* found a match; column is unique */
4266 }
4267 }
4268
4270 break; /* no match; this index doesn't help us */
4271 }
4272
4273 /* Matched all key columns of this index? */
4275 {
4276 if (extra_clauses)
4277 *extra_clauses = exprs;
4278 return true;
4279 }
4280 }
4281
4282 return false;
4283}
4284
4285/*
4286 * indexcol_is_bool_constant_for_query
4287 *
4288 * If an index column is constrained to have a constant value by the query's
4289 * WHERE conditions, then it's irrelevant for sort-order considerations.
4290 * Usually that means we have a restriction clause WHERE indexcol = constant,
4291 * which gets turned into an EquivalenceClass containing a constant, which
4292 * is recognized as redundant by build_index_pathkeys(). But if the index
4293 * column is a boolean variable (or expression), then we are not going to
4294 * see WHERE indexcol = constant, because expression preprocessing will have
4295 * simplified that to "WHERE indexcol" or "WHERE NOT indexcol". So we are not
4296 * going to have a matching EquivalenceClass (unless the query also contains
4297 * "ORDER BY indexcol"). To allow such cases to work the same as they would
4298 * for non-boolean values, this function is provided to detect whether the
4299 * specified index column matches a boolean restriction clause.
4300 */
4301bool
4304 int indexcol)
4305{
4307
4308 /* If the index isn't boolean, we can't possibly get a match */
4310 return false;
4311
4312 /* Check each restriction clause for the index's rel */
4314 {
4316
4317 /*
4318 * As in match_clause_to_indexcol, never match pseudoconstants to
4319 * indexes. (It might be semantically okay to do so here, but the
4320 * odds of getting a match are negligible, so don't waste the cycles.)
4321 */
4322 if (rinfo->pseudoconstant)
4323 continue;
4324
4325 /* See if we can match the clause's expression to the index column */
4327 return true;
4328 }
4329
4330 return false;
4331}
4332
4333
4334/****************************************************************************
4335 * ---- ROUTINES TO CHECK OPERANDS ----
4336 ****************************************************************************/
4337
4338/*
4339 * match_index_to_operand()
4340 * Generalized test for a match between an index's key
4341 * and the operand on one side of a restriction or join clause.
4342 *
4343 * operand: the nodetree to be compared to the index
4344 * indexcol: the column number of the index (counting from 0)
4345 * index: the index of interest
4346 *
4347 * Note that we aren't interested in collations here; the caller must check
4348 * for a collation match, if it's dealing with an operator where that matters.
4349 *
4350 * This is exported for use in selfuncs.c.
4351 */
4352bool
4354 int indexcol,
4356{
4358
4359 /*
4360 * Ignore any PlaceHolderVar node contained in the operand. This is
4361 * needed to be able to apply indexscanning in cases where the operand (or
4362 * a subtree) has been wrapped in PlaceHolderVars to enforce separate
4363 * identity or as a result of outer joins.
4364 */
4365 operand = strip_phvs_in_index_operand(operand);
4366
4367 /*
4368 * Ignore any RelabelType node above the operand. This is needed to be
4369 * able to apply indexscanning in binary-compatible-operator cases.
4370 *
4371 * Note: we must handle nested RelabelType nodes here. While
4372 * eval_const_expressions() will have simplified them to at most one
4373 * layer, our prior stripping of PlaceHolderVars may have brought separate
4374 * RelabelTypes into adjacency.
4375 */
4378
4381 {
4382 /*
4383 * Simple index column; operand must be a matching Var.
4384 */
4389 return true;
4390 }
4391 else
4392 {
4393 /*
4394 * Index expression; find the correct expression. (This search could
4395 * be avoided, at the cost of complicating all the callers of this
4396 * routine; doesn't seem worth it.)
4397 */
4401
4404 {
4406 {
4410 }
4411 }
4415
4416 /*
4417 * Does it match the operand? Again, strip any relabeling.
4418 */
4421
4423 return true;
4424 }
4425
4426 return false;
4427}
4428
4429/*
4430 * strip_phvs_in_index_operand
4431 * Strip PlaceHolderVar nodes from the given operand expression to
4432 * facilitate matching against an index's key.
4433 *
4434 * A PlaceHolderVar appearing in a relation-scan-level expression is
4435 * effectively a no-op. Nevertheless, to play it safe, we strip only
4436 * PlaceHolderVars that are not marked nullable.
4437 *
4438 * The removal is performed recursively because PlaceHolderVars can be nested
4439 * or interleaved with other node types. We must peel back all layers to
4440 * expose the base operand.
4441 *
4442 * As a performance optimization, we first use a lightweight walker to check
4443 * for the presence of strippable PlaceHolderVars. The expensive mutator is
4444 * invoked only if a candidate is found, avoiding unnecessary memory allocation
4445 * and tree copying in the common case where no PlaceHolderVars are present.
4446 */
4447Node *
4449{
4450 /* Don't mutate/copy if no target PHVs exist */
4452 return operand;
4453
4455}
4456
4457/*
4458 * contain_strippable_phv_walker
4459 * Detect if there are any PlaceHolderVars in the tree that are candidates
4460 * for stripping.
4461 *
4462 * We identify a PlaceHolderVar as strippable only if its phnullingrels is
4463 * empty.
4464 */
4465static bool
4467{
4469 return false;
4470
4472 {
4474
4476 return true;
4477 }
4478
4480 context);
4481}
4482
4483/*
4484 * strip_phvs_in_index_operand_mutator
4485 * Recursively remove PlaceHolderVars in the tree that match the criteria.
4486 *
4487 * We strip a PlaceHolderVar only if its phnullingrels is empty, replacing it
4488 * with its contained expression.
4489 */
4492{
4495
4497 {
4499
4500 /* If matches the criteria, strip it */
4502 {
4503 /* Recurse on its contained expression */
4505 context);
4506 }
4507
4508 /* Otherwise, keep this PHV but check its contained expression */
4509 }
4510
4512 context);
4513}
4514
4515/*
4516 * is_pseudo_constant_for_index()
4517 * Test whether the given expression can be used as an indexscan
4518 * comparison value.
4519 *
4520 * An indexscan comparison value must not contain any volatile functions,
4521 * and it can't contain any Vars of the index's own table. Vars of
4522 * other tables are okay, though; in that case we'd be producing an
4523 * indexqual usable in a parameterized indexscan. This is, therefore,
4524 * a weaker condition than is_pseudo_constant_clause().
4525 *
4526 * This function is exported for use by planner support functions,
4527 * which will have available the IndexOptInfo, but not any RestrictInfo
4528 * infrastructure. It is making the same test made by functions above
4529 * such as match_opclause_to_indexcol(), but those rely where possible
4530 * on RestrictInfo information about variable membership.
4531 *
4532 * expr: the nodetree to be checked
4533 * index: the index of interest
4534 */
4535bool
4537{
4538 /* pull_varnos is cheaper than volatility check, so do that first */
4540 return false; /* no good, contains Var of table */
4542 return false; /* no good, volatile comparison value */
4543 return true;
4544}
void create_partial_bitmap_paths(PlannerInfo *root, RelOptInfo *rel, Path *bitmapqual)
Definition allpaths.c:4690
Bitmapset * bms_difference(const Bitmapset *a, const Bitmapset *b)
Definition bitmapset.c:346
BMS_Comparison bms_subset_compare(const Bitmapset *a, const Bitmapset *b)
Definition bitmapset.c:445
Bitmapset * bms_del_members(Bitmapset *a, const Bitmapset *b)
Definition bitmapset.c:1160
Bitmapset * bms_add_members(Bitmapset *a, const Bitmapset *b)
Definition bitmapset.c:916
ScalarArrayOpExpr * make_SAOP_expr(Oid oper, Node *leftexpr, Oid coltype, Oid arraycollid, Oid inputcollid, List *exprs, bool haveNonConst)
Definition clauses.c:5832
void cost_bitmap_tree_node(Path *path, Cost *cost, Selectivity *selec)
Definition costsize.c:1114
void cost_bitmap_heap_scan(Path *path, PlannerInfo *root, RelOptInfo *baserel, ParamPathInfo *param_info, Path *bitmapqual, double loop_count)
Definition costsize.c:1011
void setup_eclass_member_iterator(EquivalenceMemberIterator *it, EquivalenceClass *ec, Relids child_relids)
Definition equivclass.c:3155
List * generate_implied_equalities_for_column(PlannerInfo *root, RelOptInfo *rel, ec_matches_callback_type callback, void *callback_arg, Relids prohibited_rels)
Definition equivclass.c:3238
EquivalenceMember * eclass_member_iterator_next(EquivalenceMemberIterator *it)
Definition equivclass.c:3174
List * generate_join_implied_equalities(PlannerInfo *root, Relids join_relids, Relids outer_relids, RelOptInfo *inner_rel, SpecialJoinInfo *sjinfo)
Definition equivclass.c:1549
static Path * choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel, List *paths)
Definition indxpath.c:1785
static Cost bitmap_and_cost_est(PlannerInfo *root, RelOptInfo *rel, List *paths)
Definition indxpath.c:2057
static void find_indexpath_quals(Path *bitmapqual, List **quals, List **preds)
Definition indxpath.c:2154
static void get_join_index_paths(PlannerInfo *root, RelOptInfo *rel, IndexOptInfo *index, IndexClauseSet *rclauseset, IndexClauseSet *jclauseset, IndexClauseSet *eclauseset, List **bitindexpaths, Relids relids, List **considered_relids)
Definition indxpath.c:606
static int or_arg_index_match_cmp(const void *a, const void *b)
Definition indxpath.c:1200
static void match_clause_to_index(PlannerInfo *root, RestrictInfo *rinfo, IndexOptInfo *index, IndexClauseSet *clauseset)
Definition indxpath.c:2586
bool is_pseudo_constant_for_index(PlannerInfo *root, Node *expr, IndexOptInfo *index)
Definition indxpath.c:4537
static bool eclass_already_used(EquivalenceClass *parent_ec, Relids oldrelids, List *indexjoinclauses)
Definition indxpath.c:684
static void match_join_clauses_to_index(PlannerInfo *root, RelOptInfo *rel, IndexOptInfo *index, IndexClauseSet *clauseset, List **joinorclauses)
Definition indxpath.c:2481
static IndexClause * match_saopclause_to_indexcol(PlannerInfo *root, RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
Definition indxpath.c:3134
static bool check_index_only(RelOptInfo *rel, IndexOptInfo *index)
Definition indxpath.c:2227
static void match_eclass_clauses_to_index(PlannerInfo *root, IndexOptInfo *index, IndexClauseSet *clauseset)
Definition indxpath.c:2515
static PathClauseUsage * classify_index_clause_usage(Path *path, List **clauselist)
Definition indxpath.c:2086
static void get_index_paths(PlannerInfo *root, RelOptInfo *rel, IndexOptInfo *index, IndexClauseSet *clauses, List **bitindexpaths)
Definition indxpath.c:716
Node * strip_phvs_in_index_operand(Node *operand)
Definition indxpath.c:4449
void check_index_predicates(PlannerInfo *root, RelOptInfo *rel)
Definition indxpath.c:3941
static List * build_index_paths(PlannerInfo *root, RelOptInfo *rel, IndexOptInfo *index, IndexClauseSet *clauses, bool useful_predicate, ScanTypeControl scantype, bool *skip_nonnative_saop)
Definition indxpath.c:810
static void match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys, List **orderby_clauses_p, List **clause_columns_p)
Definition indxpath.c:3716
static int find_list_position(Node *node, List **nodelist)
Definition indxpath.c:2201
static void match_clauses_to_index(PlannerInfo *root, List *clauses, IndexOptInfo *index, IndexClauseSet *clauseset)
Definition indxpath.c:2553
static double get_loop_count(PlannerInfo *root, Index cur_relid, Relids outer_relids)
Definition indxpath.c:2326
static void consider_index_join_outer_rels(PlannerInfo *root, RelOptInfo *rel, IndexOptInfo *index, IndexClauseSet *rclauseset, IndexClauseSet *jclauseset, IndexClauseSet *eclauseset, List **bitindexpaths, List *indexjoinclauses, int considered_clauses, List **considered_relids)
Definition indxpath.c:503
void create_index_paths(PlannerInfo *root, RelOptInfo *rel)
Definition indxpath.c:240
static double adjust_rowcount_for_semijoins(PlannerInfo *root, Index cur_relid, Index outer_relid, double rowcount)
Definition indxpath.c:2379
static IndexClause * match_clause_to_indexcol(PlannerInfo *root, RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
Definition indxpath.c:2710
static bool ec_member_matches_indexcol(PlannerInfo *root, RelOptInfo *rel, EquivalenceClass *ec, EquivalenceMember *em, void *arg)
Definition indxpath.c:4089
static IndexClause * get_index_clause_from_support(PlannerInfo *root, RestrictInfo *rinfo, Oid funcid, int indexarg, int indexcol, IndexOptInfo *index)
Definition indxpath.c:3068
#define IndexCollMatchesExprColl(idxcollation, exprcollation)
Definition indxpath.c:40
static IndexClause * match_orclause_to_indexcol(PlannerInfo *root, RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
Definition indxpath.c:3296
static IndexClause * match_opclause_to_indexcol(PlannerInfo *root, RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
Definition indxpath.c:2903
static Cost bitmap_scan_cost_est(PlannerInfo *root, RelOptInfo *rel, Path *ipath)
Definition indxpath.c:2023
bool match_index_to_operand(Node *operand, int indexcol, IndexOptInfo *index)
Definition indxpath.c:4354
static IndexClause * match_boolean_index_clause(PlannerInfo *root, RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
Definition indxpath.c:2816
static void consider_index_join_clauses(PlannerInfo *root, RelOptInfo *rel, IndexOptInfo *index, IndexClauseSet *rclauseset, IndexClauseSet *jclauseset, IndexClauseSet *eclauseset, List **bitindexpaths)
Definition indxpath.c:437
static int or_arg_index_match_cmp_group(const void *a, const void *b)
Definition indxpath.c:1238
static Node * strip_phvs_in_index_operand_mutator(Node *node, void *context)
Definition indxpath.c:4492
static IndexClause * expand_indexqual_rowcompare(PlannerInfo *root, RestrictInfo *rinfo, int indexcol, IndexOptInfo *index, Oid expr_op, bool var_on_left)
Definition indxpath.c:3494
static void match_restriction_clauses_to_index(PlannerInfo *root, IndexOptInfo *index, IndexClauseSet *clauseset)
Definition indxpath.c:2465
static IndexClause * match_rowcompare_to_indexcol(PlannerInfo *root, RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
Definition indxpath.c:3202
static List * build_paths_for_OR(PlannerInfo *root, RelOptInfo *rel, List *clauses, List *other_clauses)
Definition indxpath.c:1092
bool indexcol_is_bool_constant_for_query(PlannerInfo *root, IndexOptInfo *index, int indexcol)
Definition indxpath.c:4303
static IndexClause * match_funcclause_to_indexcol(PlannerInfo *root, RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
Definition indxpath.c:3022
static int path_usage_comparator(const void *a, const void *b)
Definition indxpath.c:1990
static bool contain_strippable_phv_walker(Node *node, void *context)
Definition indxpath.c:4467
static List * group_similar_or_args(PlannerInfo *root, RelOptInfo *rel, RestrictInfo *rinfo)
Definition indxpath.c:1271
static double approximate_joinrel_size(PlannerInfo *root, Relids relids)
Definition indxpath.c:2423
static Expr * match_clause_to_ordering_op(IndexOptInfo *index, int indexcol, Expr *clause, Oid pk_opfamily)
Definition indxpath.c:3827
bool relation_has_unique_index_for(PlannerInfo *root, RelOptInfo *rel, List *restrictlist, List **extra_clauses)
Definition indxpath.c:4145
static List * generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel, List *clauses, List *other_clauses)
Definition indxpath.c:1629
static List * make_bitmap_paths_for_or_group(PlannerInfo *root, RelOptInfo *rel, RestrictInfo *ri, List *other_clauses)
Definition indxpath.c:1548
void get_op_opfamily_properties(Oid opno, Oid opfamily, bool ordering_op, int *strategy, Oid *lefttype, Oid *righttype)
Definition lsyscache.c:138
Oid get_op_opfamily_sortfamily(Oid opno, Oid opfamily)
Definition lsyscache.c:110
int get_op_opfamily_strategy(Oid opno, Oid opfamily)
Definition lsyscache.c:85
Oid get_opfamily_member(Oid opfamily, Oid lefttype, Oid righttype, int16 strategy)
Definition lsyscache.c:168
Expr * make_opclause(Oid opno, Oid opresulttype, bool opretset, Expr *leftop, Expr *rightop, Oid opcollid, Oid inputcollid)
Definition makefuncs.c:701
static MemoryContext MemoryContextSwitchTo(MemoryContext context)
Definition palloc.h:124
List * truncate_useless_pathkeys(PlannerInfo *root, RelOptInfo *rel, List *pathkeys)
Definition pathkeys.c:2200
bool has_useful_pathkeys(PlannerInfo *root, RelOptInfo *rel)
Definition pathkeys.c:2291
List * build_index_pathkeys(PlannerInfo *root, IndexOptInfo *index, ScanDirection scandir)
Definition pathkeys.c:740
BitmapAndPath * create_bitmap_and_path(PlannerInfo *root, RelOptInfo *rel, List *bitmapquals)
Definition pathnode.c:1129
IndexPath * create_index_path(PlannerInfo *root, IndexOptInfo *index, List *indexclauses, List *indexorderbys, List *indexorderbycols, List *pathkeys, ScanDirection indexscandir, bool indexonly, Relids required_outer, double loop_count, bool partial_path)
Definition pathnode.c:1047
void add_partial_path(RelOptInfo *parent_rel, Path *new_path)
Definition pathnode.c:793
BitmapOrPath * create_bitmap_or_path(PlannerInfo *root, RelOptInfo *rel, List *bitmapquals)
Definition pathnode.c:1181
BitmapHeapPath * create_bitmap_heap_path(PlannerInfo *root, RelOptInfo *rel, Path *bitmapqual, Relids required_outer, double loop_count, int parallel_degree)
Definition pathnode.c:1096
bool predicate_implied_by(List *predicate_list, List *clause_list, bool weak)
Definition predtest.c:152
PlanRowMark * get_plan_rowmark(List *rowmarks, Index rtindex)
Definition preptlist.c:526
Relids find_childrel_parents(PlannerInfo *root, RelOptInfo *rel)
Definition relnode.c:1657
bool restriction_is_or_clause(RestrictInfo *restrictinfo)
Definition restrictinfo.c:407
bool restriction_is_securely_promotable(RestrictInfo *restrictinfo, RelOptInfo *rel)
Definition restrictinfo.c:422
RestrictInfo * make_plain_restrictinfo(PlannerInfo *root, Expr *clause, Expr *orclause, bool is_pushed_down, bool has_clone, bool is_clone, bool pseudoconstant, Index security_level, Relids required_relids, Relids incompatible_relids, Relids outer_relids)
Definition restrictinfo.c:103
bool join_clause_is_movable_to(RestrictInfo *rinfo, RelOptInfo *baserel)
Definition restrictinfo.c:575
RestrictInfo * commute_restrictinfo(RestrictInfo *rinfo, Oid comm_op)
Definition restrictinfo.c:350
double estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows, List **pgset, EstimationInfo *estinfo)
Definition selfuncs.c:3771
Definition pathnodes.h:2121
Definition pathnodes.h:2109
Definition pathnodes.h:2134
Definition bitmapset.h:50
Definition primnodes.h:967
Definition primnodes.h:2005
Definition primnodes.h:324
Definition pathnodes.h:1634
Definition pathnodes.h:1760
Definition pathnodes.h:1695
Definition primnodes.h:189
Definition primnodes.h:779
Definition indxpath.c:53
Definition pathnodes.h:2080
Definition pathnodes.h:1329
Definition pathnodes.h:2034
Definition pg_list.h:54
Definition memnodes.h:118
Definition nodes.h:135
Definition primnodes.h:1981
Definition primnodes.h:846
Definition indxpath.c:1181
Definition indxpath.c:61
Definition pathnodes.h:1787
Definition pathnodes.h:1945
Definition pathnodes.h:3085
Definition pathnodes.h:297
Definition pathnodes.h:992
Definition primnodes.h:1215
Definition pathnodes.h:2864
Definition primnodes.h:1489
Definition primnodes.h:926
Definition pathnodes.h:3191
Definition primnodes.h:262
Definition indxpath.c:71
Definition preproc-array_of_struct.c:43
Definition pg_list.h:46
void pull_varattnos(Node *node, Index varno, Bitmapset **varattnos)
Definition var.c:296
Enumeration Type Documentation
◆ ScanTypeControl
| Enumerator | |
|---|---|
| ST_INDEXSCAN | |
| ST_BITMAPSCAN | |
| ST_ANYSCAN | |
Definition at line 44 of file indxpath.c.
45{
49} ScanTypeControl;
Function Documentation
◆ adjust_rowcount_for_semijoins()
|
static |
Definition at line 2379 of file indxpath.c.
2383{
2385
2387 {
2389
2393 {
2394 /* Estimate number of unique-ified rows */
2397
2400 sjinfo->semi_rhs_exprs,
2401 nraw,
2402 NULL,
2403 NULL);
2405 rowcount = nunique;
2406 }
2407 }
2408 return rowcount;
2409}
References approximate_joinrel_size(), bms_is_member(), estimate_num_groups(), fb(), JOIN_SEMI, SpecialJoinInfo::jointype, lfirst, root, SpecialJoinInfo::semi_rhs_exprs, SpecialJoinInfo::syn_lefthand, and SpecialJoinInfo::syn_righthand.
Referenced by get_loop_count().
◆ approximate_joinrel_size()
|
static |
Definition at line 2423 of file indxpath.c.
2424{
2425 double rowcount = 1.0;
2426 int relid;
2427
2428 relid = -1;
2430 {
2431 RelOptInfo *rel;
2432
2433 /* Paranoia: ignore bogus relid indexes */
2435 continue;
2436 rel = root->simple_rel_array[relid];
2438 continue;
2440
2441 /* Relation could be proven empty, if so ignore */
2443 continue;
2444
2445 /* Otherwise, rel's rows estimate should be valid by now */
2447
2448 /* Accumulate product */
2449 rowcount *= rel->rows;
2450 }
2451 return rowcount;
2452}
References Assert, bms_next_member(), fb(), IS_DUMMY_REL, RelOptInfo::relid, root, and RelOptInfo::rows.
Referenced by adjust_rowcount_for_semijoins().
◆ bitmap_and_cost_est()
|
static |
Definition at line 2057 of file indxpath.c.
2058{
2060
2061 /*
2062 * Might as well build a real BitmapAndPath here, as the work is slightly
2063 * too complicated to be worth repeating just to save one palloc.
2064 */
2066
2068}
References bitmap_scan_cost_est(), create_bitmap_and_path(), fb(), and root.
Referenced by choose_bitmap_and().
◆ bitmap_scan_cost_est()
|
static |
Definition at line 2023 of file indxpath.c.
2024{
2026
2027 /* Set up a dummy BitmapHeapPath */
2030 bpath.path.parent = rel;
2035
2036 /*
2037 * Check the cost of temporary path without considering parallelism.
2038 * Parallel bitmap heap path will be considered at later stage.
2039 */
2040 bpath.path.parallel_workers = 0;
2041
2042 /* Now we can do cost_bitmap_heap_scan */
2044 bpath.path.param_info,
2045 ipath,
2048
2050}
References cost_bitmap_heap_scan(), fb(), get_loop_count(), NIL, BitmapHeapPath::path, PATH_REQ_OUTER, Path::pathtype, RelOptInfo::relid, RelOptInfo::reltarget, and root.
Referenced by bitmap_and_cost_est(), and choose_bitmap_and().
◆ build_index_paths()
|
static |
Definition at line 810 of file indxpath.c.
815{
819 Relids outer_relids;
828 int indexcol;
829
831
832 /*
833 * Check that index supports the desired scan type(s)
834 */
836 {
840 break;
844 break;
846 /* either or both are OK */
847 break;
848 }
849
850 /*
851 * 1. Combine the per-column IndexClause lists into an overall list.
852 *
853 * In the resulting list, clauses are ordered by index key, so that the
854 * column numbers form a nondecreasing sequence. (This order is depended
855 * on by btree and possibly other places.) The list can be empty, if the
856 * index AM allows that.
857 *
858 * We also build a Relids set showing which outer rels are required by the
859 * selected clauses. Any lateral_relids are included in that, but not
860 * otherwise accounted for.
861 */
865 {
867
869 {
872
875 {
876 /*
877 * Caller asked us to generate IndexPaths that omit any
878 * ScalarArrayOpExpr clauses when the underlying index AM
879 * lacks native support.
880 *
881 * We must omit this clause (and tell caller about it).
882 */
884 continue;
885 }
886
887 /* OK to include this clause */
889 outer_relids = bms_add_members(outer_relids,
890 rinfo->clause_relids);
891 }
892
893 /*
894 * If no clauses match the first index column, check for amoptionalkey
895 * restriction. We can't generate a scan over an index with
896 * amoptionalkey = false unless there's at least one index clause.
897 * (When working on columns after the first, this test cannot fail. It
898 * is always okay for columns after the first to not have any
899 * clauses.)
900 */
903 }
904
905 /* We do not want the index's rel itself listed in outer_relids */
907
908 /* Compute loop_count for cost estimation purposes */
910
911 /*
912 * 2. Compute pathkeys describing index's ordering, if any, then see how
913 * many of them are actually useful for this query. This is not relevant
914 * if we are only trying to build bitmap indexscans.
915 */
920 {
922 ForwardScanDirection);
924 index_pathkeys);
927 }
929 {
930 /*
931 * See if we can generate ordering operators for query_pathkeys or at
932 * least some prefix thereof. Matching to just a prefix of the
933 * query_pathkeys will allow an incremental sort to be considered on
934 * the index's partially sorted results.
935 */
937 &orderbyclauses,
938 &orderbyclausecols);
941 else
944 }
945 else
946 {
950 }
951
952 /*
953 * 3. Check if an index-only scan is possible. If we're not building
954 * plain indexscans, this isn't relevant since bitmap scans don't support
955 * index data retrieval anyway.
956 */
959
960 /*
961 * 4. Generate an indexscan path if there are relevant restriction clauses
962 * in the current clauses, OR the index ordering is potentially useful for
963 * later merging or final output ordering, OR the index has a useful
964 * predicate, OR an index-only scan is possible.
965 */
967 index_only_scan)
968 {
970 index_clauses,
971 orderbyclauses,
972 orderbyclausecols,
973 useful_pathkeys,
974 ForwardScanDirection,
975 index_only_scan,
976 outer_relids,
977 loop_count,
978 false);
980
981 /*
982 * If appropriate, consider parallel index scan. We don't allow
983 * parallel index scan for bitmap index scans.
984 */
988 {
990 index_clauses,
991 orderbyclauses,
992 orderbyclausecols,
993 useful_pathkeys,
994 ForwardScanDirection,
995 index_only_scan,
996 outer_relids,
997 loop_count,
998 true);
999
1000 /*
1001 * if, after costing the path, we find that it's not worth using
1002 * parallel workers, just free it.
1003 */
1006 else
1008 }
1009 }
1010
1011 /*
1012 * 5. If the index is ordered, a backwards scan might be interesting.
1013 */
1015 {
1017 BackwardScanDirection);
1019 index_pathkeys);
1021 {
1023 index_clauses,
1024 NIL,
1025 NIL,
1026 useful_pathkeys,
1027 BackwardScanDirection,
1028 index_only_scan,
1029 outer_relids,
1030 loop_count,
1031 false);
1033
1034 /* If appropriate, consider parallel index scan */
1038 {
1040 index_clauses,
1041 NIL,
1042 NIL,
1043 useful_pathkeys,
1044 BackwardScanDirection,
1045 index_only_scan,
1046 outer_relids,
1047 loop_count,
1048 true);
1049
1050 /*
1051 * if, after costing the path, we find that it's not worth
1052 * using parallel workers, just free it.
1053 */
1056 else
1058 }
1059 }
1060 }
1061
1062 return result;
1063}
References add_partial_path(), Assert, BackwardScanDirection, bms_add_members(), bms_copy(), bms_del_member(), build_index_pathkeys(), check_index_only(), RestrictInfo::clause, RelOptInfo::consider_parallel, create_index_path(), fb(), ForwardScanDirection, get_loop_count(), has_useful_pathkeys(), IndexClauseSet::indexclauses, IsA, lappend(), RelOptInfo::lateral_relids, lfirst, list_copy_head(), list_length(), match_pathkeys_to_index(), NIL, pfree(), RelOptInfo::relid, root, ST_ANYSCAN, ST_BITMAPSCAN, ST_INDEXSCAN, and truncate_useless_pathkeys().
Referenced by build_paths_for_OR(), and get_index_paths().
◆ build_paths_for_OR()
|
static |
Definition at line 1092 of file indxpath.c.
1094{
1098
1100 {
1105
1106 /* Ignore index if it doesn't support bitmap scans */
1108 continue;
1109
1110 /*
1111 * Ignore partial indexes that do not match the query. If a partial
1112 * index is marked predOK then we know it's OK. Otherwise, we have to
1113 * test whether the added clauses are sufficient to imply the
1114 * predicate. If so, we can use the index in the current context.
1115 *
1116 * We set useful_predicate to true iff the predicate was proven using
1117 * the current set of clauses. This is needed to prevent matching a
1118 * predOK index to an arm of an OR, which would be a legal but
1119 * pointlessly inefficient plan. (A better plan will be generated by
1120 * just scanning the predOK index alone, no OR.)
1121 */
1124 {
1126 {
1127 /* Usable, but don't set useful_predicate */
1128 }
1129 else
1130 {
1131 /* Form all_clauses if not done already */
1134
1136 continue; /* can't use it at all */
1137
1140 }
1141 }
1142
1143 /*
1144 * Identify the restriction clauses that can match the index.
1145 */
1148
1149 /*
1150 * If no matches so far, and the index predicate isn't useful, we
1151 * don't want it.
1152 */
1154 continue;
1155
1156 /*
1157 * Add "other" restriction clauses to the clauseset.
1158 */
1160
1161 /*
1162 * Construct paths if possible.
1163 */
1166 useful_predicate,
1167 ST_BITMAPSCAN,
1168 NULL);
1170 }
1171
1172 return result;
1173}
References build_index_paths(), fb(), RelOptInfo::indexlist, lfirst, list_concat(), list_concat_copy(), match_clauses_to_index(), MemSet, NIL, predicate_implied_by(), root, and ST_BITMAPSCAN.
Referenced by generate_bitmap_or_paths(), and make_bitmap_paths_for_or_group().
◆ check_index_only()
|
static |
Definition at line 2227 of file indxpath.c.
2228{
2229 bool result;
2234
2235 /* If we're not allowed to consider index-only scans, give up now */
2237 return false;
2238
2239 /*
2240 * Check that all needed attributes of the relation are available from the
2241 * index.
2242 */
2243
2244 /*
2245 * First, identify all the attributes needed for joins or final output.
2246 * Note: we must look at rel's targetlist, not the attr_needed data,
2247 * because attr_needed isn't computed for inheritance child rels.
2248 */
2250
2251 /*
2252 * Add all the attributes used by restriction clauses; but consider only
2253 * those clauses not implied by the index predicate, since ones that are
2254 * so implied don't need to be checked explicitly in the plan.
2255 *
2256 * Note: attributes used only in index quals would not be needed at
2257 * runtime either, if we are certain that the index is not lossy. However
2258 * it'd be complicated to account for that accurately, and it doesn't
2259 * matter in most cases, since we'd conclude that such attributes are
2260 * available from the index anyway.
2261 */
2263 {
2265
2267 }
2268
2269 /*
2270 * Construct a bitmapset of columns that the index can return back in an
2271 * index-only scan.
2272 */
2274 {
2276
2277 /*
2278 * For the moment, we just ignore index expressions. It might be nice
2279 * to do something with them, later.
2280 */
2281 if (attno == 0)
2282 continue;
2283
2285 index_canreturn_attrs =
2287 attno - FirstLowInvalidHeapAttributeNumber);
2288 }
2289
2290 /* Do we have all the necessary attributes? */
2292
2293 bms_free(attrs_used);
2295
2296 return result;
2297}
References bms_add_member(), bms_free(), bms_is_subset(), RestrictInfo::clause, PathTarget::exprs, fb(), FirstLowInvalidHeapAttributeNumber, i, lfirst, PGS_CONSIDER_INDEXONLY, RelOptInfo::pgs_mask, pull_varattnos(), RelOptInfo::relid, and RelOptInfo::reltarget.
Referenced by build_index_paths().
◆ check_index_predicates()
| void check_index_predicates | ( | PlannerInfo * | root, |
| RelOptInfo * | rel | ||
| ) |
Definition at line 3941 of file indxpath.c.
3942{
3948
3949 /* Indexes are available only on base or "other" member relations. */
3951
3952 /*
3953 * Initialize the indrestrictinfo lists to be identical to
3954 * baserestrictinfo, and check whether there are any partial indexes. If
3955 * not, this is all we need to do.
3956 */
3959 {
3961
3965 }
3967 return;
3968
3969 /*
3970 * Construct a list of clauses that we can assume true for the purpose of
3971 * proving the index(es) usable. Restriction clauses for the rel are
3972 * always usable, and so are any join clauses that are "movable to" this
3973 * rel. Also, we can consider any EC-derivable join clauses (which must
3974 * be "movable to" this rel, by definition).
3975 */
3977
3978 /* Scan the rel's join clauses */
3980 {
3982
3983 /* Check if clause can be moved to this rel */
3985 continue;
3986
3988 }
3989
3990 /*
3991 * Add on any equivalence-derivable join clauses. Computing the correct
3992 * relid sets for generate_join_implied_equalities is slightly tricky
3993 * because the rel could be a child rel rather than a true baserel, and in
3994 * that case we must subtract its parents' relid(s) from all_query_rels.
3995 * Additionally, we mustn't consider clauses that are only computable
3996 * after outer joins that can null the rel.
3997 */
4001 else
4004
4006 clauselist =
4010 otherrels),
4011 otherrels,
4012 rel,
4013 NULL));
4014
4015 /*
4016 * Normally we remove quals that are implied by a partial index's
4017 * predicate from indrestrictinfo, indicating that they need not be
4018 * checked explicitly by an indexscan plan using this index. However, if
4019 * the rel is a target relation of UPDATE/DELETE/MERGE/SELECT FOR UPDATE,
4020 * we cannot remove such quals from the plan, because they need to be in
4021 * the plan so that they will be properly rechecked by EvalPlanQual
4022 * testing. Some day we might want to remove such quals from the main
4023 * plan anyway and pass them through to EvalPlanQual via a side channel;
4024 * but for now, we just don't remove implied quals at all for target
4025 * relations.
4026 */
4029
4030 /*
4031 * Now try to prove each index predicate true, and compute the
4032 * indrestrictinfo lists for partial indexes. Note that we compute the
4033 * indrestrictinfo list even for non-predOK indexes; this might seem
4034 * wasteful, but we may be able to use such indexes in OR clauses, cf
4035 * generate_bitmap_or_paths().
4036 */
4038 {
4041
4043 continue; /* ignore non-partial indexes here */
4044
4047 false);
4048
4049 /* If rel is an update target, leave indrestrictinfo as set above */
4051 continue;
4052
4053 /*
4054 * If index is !amoptionalkey, also leave indrestrictinfo as set
4055 * above. Otherwise we risk removing all quals for the first index
4056 * key and then not being able to generate an indexscan at all. It
4057 * would be better to be more selective, but we've not yet identified
4058 * which if any of the quals match the first index key.
4059 */
4061 continue;
4062
4063 /* Else compute indrestrictinfo as the non-implied quals */
4066 {
4068
4069 /* predicate_implied_by() assumes first arg is immutable */
4074 }
4075 }
4076}
References Assert, RelOptInfo::baserestrictinfo, bms_del_members(), bms_difference(), bms_is_empty, bms_is_member(), bms_union(), RestrictInfo::clause, contain_mutable_functions(), fb(), find_childrel_parents(), generate_join_implied_equalities(), get_plan_rowmark(), RelOptInfo::indexlist, IS_SIMPLE_REL, join_clause_is_movable_to(), RelOptInfo::joininfo, lappend(), lfirst, list_concat(), list_copy(), list_make1, NIL, RelOptInfo::nulling_relids, predicate_implied_by(), RelOptInfo::relid, RelOptInfo::relids, RELOPT_OTHER_MEMBER_REL, RelOptInfo::reloptkind, and root.
Referenced by set_plain_rel_size(), and set_tablesample_rel_size().
◆ choose_bitmap_and()
|
static |
Definition at line 1785 of file indxpath.c.
1786{
1794 j;
1795 ListCell *l;
1796
1800
1801 /*
1802 * In theory we should consider every nonempty subset of the given paths.
1803 * In practice that seems like overkill, given the crude nature of the
1804 * estimates, not to mention the possible effects of higher-level AND and
1805 * OR clauses. Moreover, it's completely impractical if there are a large
1806 * number of paths, since the work would grow as O(2^N).
1807 *
1808 * As a heuristic, we first check for paths using exactly the same sets of
1809 * WHERE clauses + index predicate conditions, and reject all but the
1810 * cheapest-to-scan in any such group. This primarily gets rid of indexes
1811 * that include the interesting columns but also irrelevant columns. (In
1812 * situations where the DBA has gone overboard on creating variant
1813 * indexes, this can make for a very large reduction in the number of
1814 * paths considered further.)
1815 *
1816 * We then sort the surviving paths with the cheapest-to-scan first, and
1817 * for each path, consider using that path alone as the basis for a bitmap
1818 * scan. Then we consider bitmap AND scans formed from that path plus
1819 * each subsequent (higher-cost) path, adding on a subsequent path if it
1820 * results in a reduction in the estimated total scan cost. This means we
1821 * consider about O(N^2) rather than O(2^N) path combinations, which is
1822 * quite tolerable, especially given than N is usually reasonably small
1823 * because of the prefiltering step. The cheapest of these is returned.
1824 *
1825 * We will only consider AND combinations in which no two indexes use the
1826 * same WHERE clause. This is a bit of a kluge: it's needed because
1827 * costsize.c and clausesel.c aren't very smart about redundant clauses.
1828 * They will usually double-count the redundant clauses, producing a
1829 * too-small selectivity that makes a redundant AND step look like it
1830 * reduces the total cost. Perhaps someday that code will be smarter and
1831 * we can remove this limitation. (But note that this also defends
1832 * against flat-out duplicate input paths, which can happen because
1833 * match_join_clauses_to_index will find the same OR join clauses that
1834 * extract_restriction_or_clauses has pulled OR restriction clauses out
1835 * of.)
1836 *
1837 * For the same reason, we reject AND combinations in which an index
1838 * predicate clause duplicates another clause. Here we find it necessary
1839 * to be even stricter: we'll reject a partial index if any of its
1840 * predicate clauses are implied by the set of WHERE clauses and predicate
1841 * clauses used so far. This covers cases such as a condition "x = 42"
1842 * used with a plain index, followed by a clauseless scan of a partial
1843 * index "WHERE x >= 40 AND x < 50". The partial index has been accepted
1844 * only because "x = 42" was present, and so allowing it would partially
1845 * double-count selectivity. (We could use predicate_implied_by on
1846 * regular qual clauses too, to have a more intelligent, but much more
1847 * expensive, check for redundancy --- but in most cases simple equality
1848 * seems to suffice.)
1849 */
1850
1851 /*
1852 * Extract clause usage info and detect any paths that use exactly the
1853 * same set of clauses; keep only the cheapest-to-scan of any such groups.
1854 * The surviving paths are put into an array for qsort'ing.
1855 */
1858 npaths = 0;
1859 foreach(l, paths)
1860 {
1862
1864
1865 /* If it's unclassifiable, treat it as distinct from all others */
1867 {
1869 continue;
1870 }
1871
1873 {
1876 break;
1877 }
1879 {
1880 /* duplicate clauseids, keep the cheaper one */
1885
1890 }
1891 else
1892 {
1893 /* not duplicate clauseids, add to array */
1895 }
1896 }
1897
1898 /* If only one surviving path, we're done */
1901
1902 /* Sort the surviving paths by index access cost */
1904 path_usage_comparator);
1905
1906 /*
1907 * For each surviving index, consider it as an "AND group leader", and see
1908 * whether adding on any of the later indexes results in an AND path with
1909 * cheaper total cost than before. Then take the cheapest AND group.
1910 *
1911 * Note: paths that are either clauseless or unclassifiable will have
1912 * empty clauseids, so that they will not be rejected by the clauseids
1913 * filter here, nor will they cause later paths to be rejected by it.
1914 */
1916 {
1920
1926
1928 {
1930
1932 /* Check for redundancy */
1934 continue; /* consider it redundant */
1936 {
1938
1939 /* we check each predicate clause separately */
1941 {
1943
1945 {
1947 break; /* out of inner foreach loop */
1948 }
1949 }
1951 continue;
1952 }
1953 /* tentatively add new path to paths, so we can estimate cost */
1957 {
1958 /* keep new path in paths, update subsidiary variables */
1963 pathinfo->clauseids);
1964 }
1965 else
1966 {
1967 /* reject new path, remove it from paths list */
1969 }
1970 }
1971
1972 /* Keep the cheapest AND-group (or singleton) */
1974 {
1975 bestpaths = paths;
1977 }
1978
1979 /* some easy cleanup (we don't try real hard though) */
1981 }
1982
1986}
References Assert, bitmap_and_cost_est(), bitmap_scan_cost_est(), bms_add_members(), bms_copy(), bms_equal(), bms_overlap(), classify_index_clause_usage(), cost_bitmap_tree_node(), create_bitmap_and_path(), fb(), i, j, lappend(), lfirst, linitial, list_concat(), list_concat_copy(), list_free(), list_length(), list_make1, list_truncate(), NIL, palloc_array, path_usage_comparator(), predicate_implied_by(), qsort, and root.
Referenced by create_index_paths(), generate_bitmap_or_paths(), and make_bitmap_paths_for_or_group().
◆ classify_index_clause_usage()
|
static |
Definition at line 2086 of file indxpath.c.
2087{
2088 PathClauseUsage *result;
2089 Bitmapset *clauseids;
2091
2093 result->path = path;
2094
2095 /* Recursively find the quals and preds used by the path */
2099
2100 /*
2101 * Some machine-generated queries have outlandish numbers of qual clauses.
2102 * To avoid getting into O(N^2) behavior even in this preliminary
2103 * classification step, we want to limit the number of entries we can
2104 * accumulate in *clauselist. Treat any path with more than 100 quals +
2105 * preds as unclassifiable, which will cause calling code to consider it
2106 * distinct from all other paths.
2107 */
2109 {
2112 return result;
2113 }
2114
2115 /* Build up a bitmapset representing the quals and preds */
2116 clauseids = NULL;
2118 {
2120
2121 clauseids = bms_add_member(clauseids,
2123 }
2125 {
2127
2128 clauseids = bms_add_member(clauseids,
2130 }
2131 result->clauseids = clauseids;
2133
2134 return result;
2135}
References bms_add_member(), PathClauseUsage::clauseids, fb(), find_indexpath_quals(), find_list_position(), lfirst, list_length(), NIL, palloc_object, PathClauseUsage::path, PathClauseUsage::preds, PathClauseUsage::quals, and PathClauseUsage::unclassifiable.
Referenced by choose_bitmap_and().
◆ consider_index_join_clauses()
|
static |
Definition at line 437 of file indxpath.c.
443{
446 int indexcol;
447
448 /*
449 * The strategy here is to identify every potentially useful set of outer
450 * rels that can provide indexable join clauses. For each such set,
451 * select all the join clauses available from those outer rels, add on all
452 * the indexable restriction clauses, and generate plain and/or bitmap
453 * index paths for that set of clauses. This is based on the assumption
454 * that it's always better to apply a clause as an indexqual than as a
455 * filter (qpqual); which is where an available clause would end up being
456 * applied if we omit it from the indexquals.
457 *
458 * This looks expensive, but in most practical cases there won't be very
459 * many distinct sets of outer rels to consider. As a safety valve when
460 * that's not true, we use a heuristic: limit the number of outer rel sets
461 * considered to a multiple of the number of clauses considered. (We'll
462 * always consider using each individual join clause, though.)
463 *
464 * For simplicity in selecting relevant clauses, we represent each set of
465 * outer rels as a maximum set of clause_relids --- that is, the indexed
466 * relation itself is also included in the relids set. considered_relids
467 * lists all relids sets we've already tried.
468 */
470 {
471 /* Consider each applicable simple join clause */
475 bitindexpaths,
476 jclauseset->indexclauses[indexcol],
477 considered_clauses,
478 &considered_relids);
479 /* Consider each applicable eclass join clause */
483 bitindexpaths,
484 eclauseset->indexclauses[indexcol],
485 considered_clauses,
486 &considered_relids);
487 }
488}
References consider_index_join_outer_rels(), fb(), list_length(), NIL, and root.
Referenced by create_index_paths().
◆ consider_index_join_outer_rels()
|
static |
Definition at line 503 of file indxpath.c.
512{
514
515 /* Examine relids of each joinclause in the given list */
517 {
522
523 /* If we already tried its relids set, no need to do so again */
525 continue;
526
527 /*
528 * Generate the union of this clause's relids set with each
529 * previously-tried set. This ensures we try this clause along with
530 * every interesting subset of previous clauses. However, to avoid
531 * exponential growth of planning time when there are many clauses,
532 * limit the number of relid sets accepted to 10 * considered_clauses.
533 *
534 * Note: get_join_index_paths appends entries to *considered_relids,
535 * but we do not need to visit such newly-added entries within this
536 * loop, so we don't use foreach() here. No real harm would be done
537 * if we did visit them, since the subset check would reject them; but
538 * it would waste some cycles.
539 */
542 {
544
545 /*
546 * If either is a subset of the other, no new set is possible.
547 * This isn't a complete test for redundancy, but it's easy and
548 * cheap. get_join_index_paths will check more carefully if we
549 * already generated the same relids set.
550 */
552 continue;
553
554 /*
555 * If this clause was derived from an equivalence class, the
556 * clause list may contain other clauses derived from the same
557 * eclass. We should not consider that combining this clause with
558 * one of those clauses generates a usefully different
559 * parameterization; so skip if any clause derived from the same
560 * eclass would already have been included when using oldrelids.
561 */
562 if (parent_ec &&
564 indexjoinclauses))
565 continue;
566
567 /*
568 * If the number of relid sets considered exceeds our heuristic
569 * limit, stop considering combinations of clauses. We'll still
570 * consider the current clause alone, though (below this loop).
571 */
573 break;
574
575 /* OK, try the union set */
578 bitindexpaths,
580 considered_relids);
581 }
582
583 /* Also try this set of relids by itself */
586 bitindexpaths,
587 clause_relids,
588 considered_relids);
589 }
590}
References BMS_DIFFERENT, bms_subset_compare(), bms_union(), eclass_already_used(), fb(), get_join_index_paths(), lfirst, list_length(), list_member(), list_nth(), and root.
Referenced by consider_index_join_clauses().
◆ contain_strippable_phv_walker()
Definition at line 4467 of file indxpath.c.
4468{
4470 return false;
4471
4473 {
4475
4477 return true;
4478 }
4479
4481 context);
4482}
References bms_is_empty, contain_strippable_phv_walker(), expression_tree_walker, fb(), and IsA.
Referenced by contain_strippable_phv_walker(), and strip_phvs_in_index_operand().
◆ create_index_paths()
| void create_index_paths | ( | PlannerInfo * | root, |
| RelOptInfo * | rel | ||
| ) |
Definition at line 240 of file indxpath.c.
241{
250
251 /* Skip the whole mess if no indexes */
253 return;
254
255 /* Bitmap paths are collected and then dealt with at the end */
257
258 /* Examine each index in turn */
260 {
262
263 /* Protect limited-size array in IndexClauseSets */
265
266 /*
267 * Ignore partial indexes that do not match the query.
268 * (generate_bitmap_or_paths() might be able to do something with
269 * them, but that's of no concern here.)
270 */
272 continue;
273
274 /*
275 * Identify the restriction clauses that can match the index.
276 */
279
280 /*
281 * Build index paths from the restriction clauses. These will be
282 * non-parameterized paths. Plain paths go directly to add_path(),
283 * bitmap paths are added to bitindexpaths to be handled below.
284 */
286 &bitindexpaths);
287
288 /*
289 * Identify the join clauses that can match the index. For the moment
290 * we keep them separate from the restriction clauses. Note that this
291 * step finds only "loose" join clauses that have not been merged into
292 * EquivalenceClasses. Also, collect join OR clauses for later.
293 */
297
298 /*
299 * Look for EquivalenceClasses that can generate joinclauses matching
300 * the index.
301 */
304 &eclauseset);
305
306 /*
307 * If we found any plain or eclass join clauses, build parameterized
308 * index paths using them.
309 */
312 &rclauseset,
313 &jclauseset,
314 &eclauseset,
315 &bitjoinpaths);
316 }
317
318 /*
319 * Generate BitmapOrPaths for any suitable OR-clauses present in the
320 * restriction list. Add these to bitindexpaths.
321 */
325
326 /*
327 * Likewise, generate BitmapOrPaths for any suitable OR-clauses present in
328 * the joinclause list. Add these to bitjoinpaths.
329 */
333
334 /*
335 * If we found anything usable, generate a BitmapHeapPath for the most
336 * promising combination of restriction bitmap index paths. Note there
337 * will be only one such path no matter how many indexes exist. This
338 * should be sufficient since there's basically only one figure of merit
339 * (total cost) for such a path.
340 */
342 {
343 Path *bitmapqual;
345
348 rel->lateral_relids, 1.0, 0);
350
351 /* create a partial bitmap heap path */
354 }
355
356 /*
357 * Likewise, if we found anything usable, generate BitmapHeapPaths for the
358 * most promising combinations of join bitmap index paths. Our strategy
359 * is to generate one such path for each distinct parameterization seen
360 * among the available bitmap index paths. This may look pretty
361 * expensive, but usually there won't be very many distinct
362 * parameterizations. (This logic is quite similar to that in
363 * consider_index_join_clauses, but we're working with whole paths not
364 * individual clauses.)
365 */
367 {
369
370 /* Identify each distinct parameterization seen in bitjoinpaths */
373 {
376
378 required_outer);
379 }
380
381 /* Now, for each distinct parameterization set ... */
383 {
386 Path *bitmapqual;
391
392 /* Identify all the bitmap join paths needing no more than that */
395 {
397
400 }
401
402 /*
403 * Add in restriction bitmap paths, since they can be used
404 * together with any join paths.
405 */
407
408 /* Select best AND combination for this parameterization */
410
411 /* And push that path into the mix */
417 }
418 }
419}
References add_path(), Assert, RelOptInfo::baserestrictinfo, bms_is_subset(), choose_bitmap_and(), consider_index_join_clauses(), RelOptInfo::consider_parallel, create_bitmap_heap_path(), create_partial_bitmap_paths(), fb(), generate_bitmap_or_paths(), get_index_paths(), get_loop_count(), INDEX_MAX_KEYS, RelOptInfo::indexlist, lappend(), RelOptInfo::lateral_relids, lfirst, list_append_unique(), list_concat(), match_eclass_clauses_to_index(), match_join_clauses_to_index(), match_restriction_clauses_to_index(), MemSet, NIL, PATH_REQ_OUTER, RelOptInfo::relid, and root.
Referenced by set_plain_rel_pathlist().
◆ ec_member_matches_indexcol()
|
static |
Definition at line 4089 of file indxpath.c.
4092{
4097
4099
4102
4103 /*
4104 * If it's a btree index, we can reject it if its opfamily isn't
4105 * compatible with the EC, since no clause generated from the EC could be
4106 * used with the index. For non-btree indexes, we can't easily tell
4107 * whether clauses generated from the EC could be used with the index, so
4108 * don't check the opfamily. This might mean we return "true" for a
4109 * useless EC, so we have to recheck the results of
4110 * generate_implied_equalities_for_column; see
4111 * match_eclass_clauses_to_index.
4112 */
4115 return false;
4116
4117 /* We insist on collation match for all index types, though */
4119 return false;
4120
4122}
References arg, Assert, EquivalenceClass::ec_collation, EquivalenceClass::ec_opfamilies, fb(), IndexCollMatchesExprColl, list_member_oid(), and match_index_to_operand().
Referenced by match_eclass_clauses_to_index().
◆ eclass_already_used()
|
static |
Definition at line 684 of file indxpath.c.
686{
688
690 {
693
694 if (rinfo->parent_ec == parent_ec &&
696 return true;
697 }
698 return false;
699}
References bms_is_subset(), fb(), and lfirst.
Referenced by consider_index_join_outer_rels().
◆ expand_indexqual_rowcompare()
|
static |
Definition at line 3494 of file indxpath.c.
3500{
3503 int op_strategy;
3514
3515 iclause->rinfo = rinfo;
3516 iclause->indexcol = indexcol;
3517
3519 {
3520 var_args = clause->largs;
3521 non_var_args = clause->rargs;
3522 }
3523 else
3524 {
3525 var_args = clause->rargs;
3526 non_var_args = clause->largs;
3527 }
3528
3530 &op_strategy,
3531 &op_lefttype,
3532 &op_righttype);
3533
3534 /* Initialize returned list of which index columns are used */
3536
3537 /* Build lists of ops, opfamilies and operator datatypes in case needed */
3542
3543 /*
3544 * See how many of the remaining columns match some index column in the
3545 * same way. As in match_clause_to_indexcol(), the "other" side of any
3546 * potential index condition is OK as long as it doesn't use Vars from the
3547 * indexed relation.
3548 */
3549 matching_cols = 1;
3550
3552 {
3556
3559 {
3560 /* indexkey is on right, so commute the operator */
3563 break; /* operator is not usable */
3564 }
3566 break; /* no good, Var on wrong side */
3568 break; /* no good, volatile comparison value */
3569
3570 /*
3571 * The Var side can match any key column of the index.
3572 */
3574 {
3579 list_nth_oid(clause->inputcollids,
3580 matching_cols)))
3581 break;
3582 }
3584 break; /* no match found */
3585
3586 /* Add column number to returned list */
3588
3589 /* Add operator info to lists */
3591 &op_strategy,
3592 &op_lefttype,
3593 &op_righttype);
3598
3599 /* This column matches, keep scanning */
3600 matching_cols++;
3601 }
3602
3603 /* Result is non-lossy if all columns are usable as index quals */
3605
3606 /*
3607 * We can use rinfo->clause as-is if we have var on left and it's all
3608 * usable as index quals.
3609 */
3612 else
3613 {
3614 /*
3615 * We have to generate a modified rowcompare (possibly just one
3616 * OpExpr). The painful part of this is changing < to <= or > to >=,
3617 * so deal with that first.
3618 */
3620 {
3621 /* very easy, just use the commuted operators */
3623 }
3625 op_strategy == BTGreaterEqualStrategyNumber)
3626 {
3627 /* easy, just use the same (possibly commuted) operators */
3629 }
3630 else
3631 {
3635
3637 op_strategy = BTLessEqualStrategyNumber;
3639 op_strategy = BTGreaterEqualStrategyNumber;
3640 else
3646 {
3650
3652 op_strategy);
3655 op_strategy, lefttype, righttype, opfam);
3657 }
3658 }
3659
3660 /* If we have more than one matching col, create a subset rowcompare */
3662 {
3664
3666 rc->opnos = new_ops;
3667 rc->opfamilies = list_copy_head(clause->opfamilies,
3668 matching_cols);
3669 rc->inputcollids = list_copy_head(clause->inputcollids,
3670 matching_cols);
3674 (Expr *) rc));
3675 }
3676 else
3677 {
3678 Expr *op;
3679
3680 /* We don't report an index column list in this case */
3682
3686 InvalidOid,
3687 linitial_oid(clause->inputcollids));
3689 }
3690 }
3691
3693}
References bms_is_member(), BTGreaterEqualStrategyNumber, BTGreaterStrategyNumber, BTLessEqualStrategyNumber, BTLessStrategyNumber, RestrictInfo::clause, RowCompareExpr::cmptype, contain_volatile_functions(), copyObject, elog, ERROR, fb(), forthree, get_commutator(), get_op_opfamily_properties(), get_op_opfamily_strategy(), get_opfamily_member(), i, IndexCollMatchesExprColl, InvalidOid, lappend_int(), lappend_oid(), RowCompareExpr::largs, lfirst_oid, linitial, linitial_oid, list_copy_head(), list_length(), list_make1, list_make1_int, list_make1_oid, list_nth(), list_nth_oid(), list_truncate(), make_opclause(), make_simple_restrictinfo, makeNode, match_index_to_operand(), NIL, OidIsValid, pull_varnos(), RowCompareExpr::rargs, and root.
Referenced by match_rowcompare_to_indexcol().
◆ find_indexpath_quals()
Definition at line 2154 of file indxpath.c.
2155{
2157 {
2159 ListCell *l;
2160
2162 {
2164 }
2165 }
2167 {
2169 ListCell *l;
2170
2172 {
2174 }
2175 }
2177 {
2179 ListCell *l;
2180
2182 {
2184
2186 }
2188 }
2189 else
2191}
References elog, ERROR, fb(), find_indexpath_quals(), IsA, lappend(), lfirst, list_concat(), and nodeTag.
Referenced by classify_index_clause_usage(), and find_indexpath_quals().
◆ find_list_position()
Definition at line 2201 of file indxpath.c.
References equal(), fb(), i, lappend(), and lfirst.
Referenced by classify_index_clause_usage().
◆ generate_bitmap_or_paths()
|
static |
Definition at line 1629 of file indxpath.c.
1631{
1635
1636 /*
1637 * We can use both the current and other clauses as context for
1638 * build_paths_for_OR; no need to remove ORs from the lists.
1639 */
1641
1643 {
1645 List *pathlist;
1646 Path *bitmapqual;
1650
1651 /* Ignore RestrictInfos that aren't ORs */
1653 continue;
1654
1655 /*
1656 * We must be able to match at least one index to each of the arms of
1657 * the OR, else we can't use it.
1658 */
1659 pathlist = NIL;
1660
1661 /*
1662 * Group the similar OR-clause arguments into dedicated RestrictInfos,
1663 * because each of those RestrictInfos has a chance to match the index
1664 * as a whole.
1665 */
1667
1669 {
1670 /*
1671 * Some parts of the rinfo were probably grouped. In this case,
1672 * we have a set of sub-rinfos that together are an exact
1673 * duplicate of rinfo. Thus, we need to remove the rinfo from
1674 * other clauses. match_clauses_to_index detects duplicated
1675 * iclauses by comparing pointers to original rinfos that would be
1676 * different. So, we must delete rinfo to avoid de-facto
1677 * duplicated clauses in the index clauses list.
1678 */
1680 }
1681
1683 {
1686
1687 /* OR arguments should be ANDs or sub-RestrictInfos */
1689 {
1691
1693 andargs,
1694 all_clauses);
1695
1696 /* Recurse in case there are sub-ORs */
1699 andargs,
1700 all_clauses));
1701 }
1703 {
1705
1706 /*
1707 * Generate bitmap paths for the group of similar OR-clause
1708 * arguments.
1709 */
1711 rel, ri,
1712 inner_other_clauses);
1713
1715 {
1716 pathlist = NIL;
1717 break;
1718 }
1719 else
1720 {
1722 continue;
1723 }
1724 }
1725 else
1726 {
1729
1731
1733 orargs,
1734 all_clauses);
1735 }
1736
1737 /*
1738 * If nothing matched this arm, we can't do anything with this OR
1739 * clause.
1740 */
1742 {
1743 pathlist = NIL;
1744 break;
1745 }
1746
1747 /*
1748 * OK, pick the most promising AND combination, and add it to
1749 * pathlist.
1750 */
1752 pathlist = lappend(pathlist, bitmapqual);
1753 }
1754
1757
1758 /*
1759 * If we have a match for every arm, then turn them into a
1760 * BitmapOrPath, and add to result list.
1761 */
1763 {
1765 result = lappend(result, bitmapqual);
1766 }
1767 }
1768
1769 return result;
1770}
References build_paths_for_OR(), castNode, choose_bitmap_and(), create_bitmap_or_path(), fb(), generate_bitmap_or_paths(), group_similar_or_args(), is_andclause(), j, lappend(), lfirst, lfirst_node, list_concat(), list_concat_copy(), list_copy(), list_delete(), list_free(), list_make1, make_bitmap_paths_for_or_group(), NIL, restriction_is_or_clause(), and root.
Referenced by create_index_paths(), and generate_bitmap_or_paths().
◆ get_index_clause_from_support()
|
static |
Definition at line 3068 of file indxpath.c.
3074{
3078
3081
3084 req.funcid = funcid;
3086 req.indexarg = indexarg;
3088 req.indexcol = indexcol;
3091
3093
3097
3099 {
3103
3104 /*
3105 * The support function API says it should just give back bare
3106 * clauses, so here we must wrap each one in a RestrictInfo.
3107 */
3109 {
3111
3112 indexquals = lappend(indexquals,
3114 }
3115
3116 iclause->rinfo = rinfo;
3117 iclause->indexquals = indexquals;
3119 iclause->indexcol = indexcol;
3121
3123 }
3124
3126}
References RestrictInfo::clause, DatumGetPointer(), fb(), get_func_support(), lappend(), lfirst, make_simple_restrictinfo, makeNode, NIL, OidFunctionCall1, OidIsValid, PointerGetDatum(), root, and List::type.
Referenced by match_funcclause_to_indexcol(), and match_opclause_to_indexcol().
◆ get_index_paths()
|
static |
Definition at line 716 of file indxpath.c.
719{
723
724 /*
725 * Build simple index paths using the clauses. Allow ScalarArrayOpExpr
726 * clauses only if the index AM supports them natively.
727 */
729 index, clauses,
730 index->predOK,
731 ST_ANYSCAN,
732 &skip_nonnative_saop);
733
734 /*
735 * Submit all the ones that can form plain IndexScan plans to add_path. (A
736 * plain IndexPath can represent either a plain IndexScan or an
737 * IndexOnlyScan, but for our purposes here that distinction does not
738 * matter. However, some of the indexes might support only bitmap scans,
739 * and those we mustn't submit to add_path here.)
740 *
741 * Also, pick out the ones that are usable as bitmap scans. For that, we
742 * must discard indexes that don't support bitmap scans, and we also are
743 * only interested in paths that have some selectivity; we should discard
744 * anything that was generated solely for ordering purposes.
745 */
747 {
749
752
755 ipath->indexselectivity < 1.0))
757 }
758
759 /*
760 * If there were ScalarArrayOpExpr clauses that the index can't handle
761 * natively, generate bitmap scan paths relying on executor-managed
762 * ScalarArrayOpExpr.
763 */
765 {
767 index, clauses,
768 false,
769 ST_BITMAPSCAN,
770 NULL);
772 }
773}
References add_path(), build_index_paths(), fb(), lappend(), lfirst, list_concat(), NIL, root, ST_ANYSCAN, and ST_BITMAPSCAN.
Referenced by create_index_paths(), and get_join_index_paths().
◆ get_join_index_paths()
|
static |
Definition at line 606 of file indxpath.c.
614{
616 int indexcol;
617
618 /* If we already considered this relids set, don't repeat the work */
620 return;
621
622 /* Identify indexclauses usable with this relids set */
624
626 {
628
629 /* First find applicable simple join clauses */
631 {
633
635 clauseset.indexclauses[indexcol] =
637 }
638
639 /*
640 * Add applicable eclass join clauses. The clauses generated for each
641 * column are redundant (cf generate_implied_equalities_for_column),
642 * so we need at most one. This is the only exception to the general
643 * rule of using all available index clauses.
644 */
646 {
648
650 {
651 clauseset.indexclauses[indexcol] =
653 break;
654 }
655 }
656
657 /* Add restriction clauses */
658 clauseset.indexclauses[indexcol] =
660 rclauseset->indexclauses[indexcol]);
661
664 }
665
666 /* We should have found something, else caller passed silly relids */
668
669 /* Build index path(s) using the collected set of clauses */
671
672 /*
673 * Remember we considered paths for this set of relids.
674 */
676}
References Assert, bms_is_subset(), fb(), get_index_paths(), lappend(), lfirst, list_concat(), list_member(), MemSet, NIL, and root.
Referenced by consider_index_join_outer_rels().
◆ get_loop_count()
|
static |
Definition at line 2326 of file indxpath.c.
2327{
2328 double result;
2330
2331 /* For a non-parameterized path, just return 1.0 quickly */
2333 return 1.0;
2334
2335 result = 0.0;
2336 outer_relid = -1;
2338 {
2340 double rowcount;
2341
2342 /* Paranoia: ignore bogus relid indexes */
2344 continue;
2347 continue;
2349
2350 /* Other relation could be proven empty, if so ignore */
2352 continue;
2353
2354 /* Otherwise, rel's rows estimate should be valid by now */
2356
2357 /* Check to see if rel is on the inside of any semijoins */
2359 cur_relid,
2360 outer_relid,
2361 outer_rel->rows);
2362
2363 /* Remember smallest row count estimate among the outer rels */
2364 if (result == 0.0 || result > rowcount)
2365 result = rowcount;
2366 }
2367 /* Return 1.0 if we found no valid relations (shouldn't happen) */
2368 return (result > 0.0) ? result : 1.0;
2369}
References adjust_rowcount_for_semijoins(), Assert, bms_next_member(), fb(), IS_DUMMY_REL, and root.
Referenced by bitmap_scan_cost_est(), build_index_paths(), and create_index_paths().
◆ group_similar_or_args()
|
static |
Definition at line 1271 of file indxpath.c.
1272{
1273 int n;
1277 bool matched = false;
1283
1287
1288 /*
1289 * To avoid N^2 behavior, take utility pass along the list of OR-clause
1290 * arguments. For each argument, fill the OrArgIndexMatch structure,
1291 * which will be used to sort these arguments at the next step.
1292 */
1293 i = -1;
1296 {
1299 OpExpr *clause;
1300 Oid opno;
1302 *rightop;
1304 int indexnum;
1305 int colnum;
1306
1307 i++;
1314
1316 continue;
1317
1319
1320 /* Only operator clauses can match */
1322 continue;
1323
1325 opno = clause->opno;
1326
1327 /* Only binary operators can match */
1329 continue;
1330
1331 /*
1332 * Ignore any RelabelType node above the operands. This is needed to
1333 * be able to apply indexscanning in binary-compatible-operator cases.
1334 * Note: we can assume there is at most one RelabelType node;
1335 * eval_const_expressions() will have simplified if more than one.
1336 */
1340
1344
1345 /*
1346 * Check for clauses of the form: (indexkey operator constant) or
1347 * (constant operator indexkey). But we don't know a particular index
1348 * yet. Therefore, we try to distinguish the potential index key and
1349 * constant first, then search for a matching index key among all
1350 * indexes.
1351 */
1355 {
1356 opno = get_commutator(opno);
1357
1359 {
1360 /* commutator doesn't exist, we can't reverse the order */
1361 continue;
1362 }
1364 }
1368 {
1370 }
1371 else
1372 {
1373 continue;
1374 }
1375
1376 /*
1377 * Match non-constant part to the index key. It's possible that a
1378 * single non-constant part matches multiple index keys. It's OK, we
1379 * just stop with first matching index key. Given that this choice is
1380 * determined the same for every clause, we will group similar clauses
1381 * together anyway.
1382 */
1383 indexnum = 0;
1385 {
1387
1388 /*
1389 * Ignore index if it doesn't support bitmap scans or SAOP
1390 * clauses.
1391 */
1393 continue;
1394
1396 {
1398 {
1403 matched = true;
1404 break;
1405 }
1406 }
1407
1408 /*
1409 * Stop looping through the indexes, if we managed to match
1410 * nonConstExpr to any index column.
1411 */
1413 break;
1414 indexnum++;
1415 }
1416 }
1417
1418 /*
1419 * Fast-path check: if no clause is matching to the index column, we can
1420 * just give up at this stage and return the clause list as-is.
1421 */
1422 if (!matched)
1423 {
1426 }
1427
1428 /*
1429 * Sort clauses to make similar clauses go together. But at the same
1430 * time, we would like to change the order of clauses as little as
1431 * possible. To do so, we reorder each group of similar clauses so that
1432 * the first item of the group stays in place, and all the other items are
1433 * moved after it. So, if there are no similar clauses, the order of
1434 * clauses stays the same. When there are some groups, required
1435 * reordering happens while the rest of the clauses remain in their
1436 * places. That is achieved by assigning a 'groupindex' to each clause:
1437 * the number of the first item in the group in the original clause list.
1438 */
1440
1441 /* Assign groupindex to the sorted clauses */
1443 {
1444 /*
1445 * When two clauses are similar and should belong to the same group,
1446 * copy the 'groupindex' from the previous clause. Given we are
1447 * considering clauses in direct order, all the clauses would have a
1448 * 'groupindex' equal to the 'groupindex' of the first clause in the
1449 * group.
1450 */
1457 }
1458
1459 /* Re-sort clauses first by groupindex then by argindex */
1461
1462 /*
1463 * Group similar clauses into single sub-restrictinfo. Side effect: the
1464 * resulting list of restrictions will be sorted by indexnum and colnum.
1465 */
1466 group_start = 0;
1468 {
1469 /* Check if it's a group boundary */
1471 (i == n ||
1477 {
1478 /*
1479 * One clause in group: add it "as is" to the upper-level OR.
1480 */
1482 {
1483 result = lappend(result,
1486 }
1487 else
1488 {
1489 /*
1490 * Two or more clauses in a group: create a nested OR.
1491 */
1496
1498
1499 /* Construct the list of nested OR arguments */
1501 {
1503
1507 else
1509 }
1510
1511 /* Construct the nested OR and wrap it with RestrictInfo */
1513 make_orclause(args),
1514 make_orclause(rargs),
1515 rinfo->is_pushed_down,
1516 rinfo->has_clone,
1517 rinfo->is_clone,
1518 rinfo->pseudoconstant,
1519 rinfo->security_level,
1520 rinfo->required_relids,
1521 rinfo->incompatible_relids,
1522 rinfo->outer_relids);
1524 }
1525
1527 }
1528 }
1530 return result;
1531}
References arg, OpExpr::args, Assert, bms_is_member(), castNode, contain_volatile_functions(), fb(), get_commutator(), get_leftop(), get_rightop(), RestrictInfo::has_clone, i, RestrictInfo::incompatible_relids, RelOptInfo::indexlist, InvalidOid, RestrictInfo::is_clone, RestrictInfo::is_pushed_down, IsA, j, lappend(), lfirst, list_length(), list_nth(), make_orclause(), make_plain_restrictinfo(), match_index_to_operand(), NIL, OidIsValid, OpExpr::opno, or_arg_index_match_cmp(), or_arg_index_match_cmp_group(), RestrictInfo::outer_relids, palloc_array, pfree(), qsort, RelOptInfo::relid, RestrictInfo::required_relids, root, and RestrictInfo::security_level.
Referenced by generate_bitmap_or_paths().
◆ indexcol_is_bool_constant_for_query()
| bool indexcol_is_bool_constant_for_query | ( | PlannerInfo * | root, |
| IndexOptInfo * | index, | ||
| int | indexcol | ||
| ) |
Definition at line 4303 of file indxpath.c.
4306{
4308
4309 /* If the index isn't boolean, we can't possibly get a match */
4311 return false;
4312
4313 /* Check each restriction clause for the index's rel */
4315 {
4317
4318 /*
4319 * As in match_clause_to_indexcol, never match pseudoconstants to
4320 * indexes. (It might be semantically okay to do so here, but the
4321 * odds of getting a match are negligible, so don't waste the cycles.)
4322 */
4323 if (rinfo->pseudoconstant)
4324 continue;
4325
4326 /* See if we can match the clause's expression to the index column */
4328 return true;
4329 }
4330
4331 return false;
4332}
References fb(), IsBooleanOpfamily(), lfirst, match_boolean_index_clause(), and root.
Referenced by build_index_pathkeys().
◆ is_pseudo_constant_for_index()
| bool is_pseudo_constant_for_index | ( | PlannerInfo * | root, |
| Node * | expr, | ||
| IndexOptInfo * | index | ||
| ) |
Definition at line 4537 of file indxpath.c.
4538{
4539 /* pull_varnos is cheaper than volatility check, so do that first */
4541 return false; /* no good, contains Var of table */
4543 return false; /* no good, volatile comparison value */
4544 return true;
4545}
References bms_is_member(), contain_volatile_functions(), pull_varnos(), and root.
◆ IsBooleanOpfamily()
Definition at line 2791 of file indxpath.c.
2792{
2795 else
2797}
References fb(), FirstNormalObjectId, and op_in_opfamily().
Referenced by indexcol_is_bool_constant_for_query(), and match_clause_to_indexcol().
◆ make_bitmap_paths_for_or_group()
|
static |
Definition at line 1548 of file indxpath.c.
1550{
1557 splitcost = 0.0;
1558 Path *bitmapqual;
1560
1561 /*
1562 * First, try to match the whole group to the one index.
1563 */
1566 orargs,
1567 other_clauses);
1569 {
1573 }
1574
1575 /*
1576 * If we manage to find a bitmap scan, which uses the group of OR-clause
1577 * arguments as a whole, we can skip matching OR-clause arguments
1578 * one-by-one as long as there are no other clauses, which can bring more
1579 * efficiency to one-by-one case.
1580 */
1583
1584 /*
1585 * Also try to match all containing clauses one-by-one.
1586 */
1588 {
1590
1592 orargs,
1593 other_clauses);
1594
1596 {
1598 break;
1599 }
1600
1604 }
1605
1606 /*
1607 * Pick the best option.
1608 */
1613 else
1615}
References build_paths_for_OR(), choose_bitmap_and(), fb(), lappend(), lfirst, list_make1, NIL, root, and Path::total_cost.
Referenced by generate_bitmap_or_paths().
◆ match_boolean_index_clause()
|
static |
Definition at line 2816 of file indxpath.c.
2820{
2823
2824 /* Direct match? */
2826 {
2827 /* convert to indexkey = TRUE */
2829 (Expr *) clause,
2832 }
2833 /* NOT clause? */
2835 {
2837
2839 {
2840 /* convert to indexkey = FALSE */
2845 }
2846 }
2847
2848 /*
2849 * Since we only consider clauses at top level of WHERE, we can convert
2850 * indexkey IS TRUE and indexkey IS FALSE to index searches as well. The
2851 * different meaning for NULL isn't important.
2852 */
2854 {
2857
2860 {
2861 /* convert to indexkey = TRUE */
2866 }
2869 {
2870 /* convert to indexkey = FALSE */
2875 }
2876 }
2877
2878 /*
2879 * If we successfully made an operator clause from the given qual, we must
2880 * wrap it in an IndexClause. It's not lossy.
2881 */
2882 if (op)
2883 {
2885
2886 iclause->rinfo = rinfo;
2889 iclause->indexcol = indexcol;
2892 }
2893
2895}
References arg, RestrictInfo::clause, fb(), get_notclausearg(), InvalidOid, IS_FALSE, is_notclause(), IS_TRUE, IsA, list_make1, make_opclause(), make_simple_restrictinfo, makeBoolConst(), makeNode, match_index_to_operand(), NIL, and root.
Referenced by indexcol_is_bool_constant_for_query(), and match_clause_to_indexcol().
◆ match_clause_to_index()
|
static |
Definition at line 2586 of file indxpath.c.
2590{
2591 int indexcol;
2592
2593 /*
2594 * Never match pseudoconstants to indexes. (Normally a match could not
2595 * happen anyway, since a pseudoconstant clause couldn't contain a Var,
2596 * but what if someone builds an expression index on a constant? It's not
2597 * totally unreasonable to do so with a partial index, either.)
2598 */
2599 if (rinfo->pseudoconstant)
2600 return;
2601
2602 /*
2603 * If clause can't be used as an indexqual because it must wait till after
2604 * some lower-security-level restriction clause, reject it.
2605 */
2607 return;
2608
2609 /* OK, check each index key column for a match */
2611 {
2614
2615 /* Ignore duplicates */
2617 {
2619
2621 return;
2622 }
2623
2624 /* OK, try to match the clause to the index column */
2626 rinfo,
2627 indexcol,
2628 index);
2630 {
2631 /* Success, so record it */
2632 clauseset->indexclauses[indexcol] =
2635 return;
2636 }
2637 }
2638}
References fb(), lappend(), lfirst, match_clause_to_indexcol(), restriction_is_securely_promotable(), and root.
Referenced by match_clauses_to_index(), and match_join_clauses_to_index().
◆ match_clause_to_indexcol()
|
static |
Definition at line 2710 of file indxpath.c.
2714{
2717 Oid opfamily;
2718
2720
2721 /*
2722 * Historically this code has coped with NULL clauses. That's probably
2723 * not possible anymore, but we might as well continue to cope.
2724 */
2727
2728 /* First check for boolean-index cases. */
2729 opfamily = index->opfamily[indexcol];
2731 {
2735 }
2736
2737 /*
2738 * Clause must be an opclause, funcclause, ScalarArrayOpExpr,
2739 * RowCompareExpr, or OR-clause that could be converted to SAOP. Or, if
2740 * the index supports it, we can handle IS NULL/NOT NULL clauses.
2741 */
2743 {
2745 }
2747 {
2749 }
2751 {
2753 }
2755 {
2757 }
2759 {
2761 }
2763 {
2765
2768 {
2770 iclause->rinfo = rinfo;
2773 iclause->indexcol = indexcol;
2776 }
2777 }
2778
2780}
References Assert, RestrictInfo::clause, fb(), IsA, IsBooleanOpfamily(), list_make1, makeNode, match_boolean_index_clause(), match_funcclause_to_indexcol(), match_index_to_operand(), match_opclause_to_indexcol(), match_orclause_to_indexcol(), match_rowcompare_to_indexcol(), match_saopclause_to_indexcol(), NIL, restriction_is_or_clause(), and root.
Referenced by match_clause_to_index().
◆ match_clause_to_ordering_op()
|
static |
Definition at line 3827 of file indxpath.c.
3831{
3832 Oid opfamily;
3835 *rightop;
3838 Oid sortfamily;
3840
3842
3843 opfamily = index->opfamily[indexcol];
3845
3846 /*
3847 * Clause must be a binary opclause.
3848 */
3857
3858 /*
3859 * We can forget the whole thing right away if wrong collation.
3860 */
3863
3864 /*
3865 * Check for clauses of the form: (indexkey operator constant) or
3866 * (constant operator indexkey).
3867 */
3871 {
3873 }
3877 {
3878 /* Might match, but we need a commuted operator */
3883 }
3884 else
3886
3887 /*
3888 * Is the (commuted) operator an ordering operator for the opfamily? And
3889 * if so, does it yield the right sorting semantics?
3890 */
3892 if (sortfamily != pk_opfamily)
3894
3895 /* We have a match. Return clause or a commuted version thereof. */
3897 {
3899
3900 /* flat-copy all the fields of clause */
3902
3903 /* commute it */
3907
3909 }
3910
3911 return clause;
3912}
References Assert, contain_var_clause(), contain_volatile_functions(), fb(), get_commutator(), get_leftop(), get_op_opfamily_sortfamily(), get_rightop(), IndexCollMatchesExprColl, InvalidOid, is_opclause(), list_make2, makeNode, and match_index_to_operand().
Referenced by match_pathkeys_to_index().
◆ match_clauses_to_index()
|
static |
Definition at line 2553 of file indxpath.c.
2557{
2559
2561 {
2563
2565 }
2566}
References fb(), lfirst_node, match_clause_to_index(), and root.
Referenced by build_paths_for_OR(), match_eclass_clauses_to_index(), and match_restriction_clauses_to_index().
◆ match_eclass_clauses_to_index()
|
static |
Definition at line 2515 of file indxpath.c.
2517{
2518 int indexcol;
2519
2520 /* No work if rel is not in any such ECs */
2522 return;
2523
2525 {
2527 List *clauses;
2528
2529 /* Generate clauses, skipping any that join to lateral_referencers */
2531 arg.indexcol = indexcol;
2533 index->rel,
2535 &arg,
2536 index->rel->lateral_referencers);
2537
2538 /*
2539 * We have to check whether the results actually do match the index,
2540 * since for non-btree indexes the EC's equality operators might not
2541 * be in the index opclass (cf ec_member_matches_indexcol).
2542 */
2544 }
2545}
References arg, ec_member_matches_indexcol(), fb(), generate_implied_equalities_for_column(), match_clauses_to_index(), and root.
Referenced by create_index_paths().
◆ match_funcclause_to_indexcol()
|
static |
Definition at line 3022 of file indxpath.c.
3026{
3028 int indexarg;
3030
3031 /*
3032 * We have no built-in intelligence about function clauses, but if there's
3033 * a planner support function, it might be able to do something. But, to
3034 * cut down on wasted planning cycles, only call the support function if
3035 * at least one argument matches the target index column.
3036 *
3037 * Note that we don't insist on the other arguments being pseudoconstants;
3038 * the support function has to check that. This is to allow cases where
3039 * only some of the other arguments need to be included in the indexqual.
3040 */
3041 indexarg = 0;
3043 {
3045
3047 {
3049 rinfo,
3050 clause->funcid,
3051 indexarg,
3052 indexcol,
3053 index);
3054 }
3055
3056 indexarg++;
3057 }
3058
3060}
References FuncExpr::args, RestrictInfo::clause, fb(), FuncExpr::funcid, get_index_clause_from_support(), lfirst, match_index_to_operand(), and root.
Referenced by match_clause_to_indexcol().
◆ match_index_to_operand()
| bool match_index_to_operand | ( | Node * | operand, |
| int | indexcol, | ||
| IndexOptInfo * | index | ||
| ) |
Definition at line 4354 of file indxpath.c.
4357{
4359
4360 /*
4361 * Ignore any PlaceHolderVar node contained in the operand. This is
4362 * needed to be able to apply indexscanning in cases where the operand (or
4363 * a subtree) has been wrapped in PlaceHolderVars to enforce separate
4364 * identity or as a result of outer joins.
4365 */
4366 operand = strip_phvs_in_index_operand(operand);
4367
4368 /*
4369 * Ignore any RelabelType node above the operand. This is needed to be
4370 * able to apply indexscanning in binary-compatible-operator cases.
4371 *
4372 * Note: we must handle nested RelabelType nodes here. While
4373 * eval_const_expressions() will have simplified them to at most one
4374 * layer, our prior stripping of PlaceHolderVars may have brought separate
4375 * RelabelTypes into adjacency.
4376 */
4379
4382 {
4383 /*
4384 * Simple index column; operand must be a matching Var.
4385 */
4390 return true;
4391 }
4392 else
4393 {
4394 /*
4395 * Index expression; find the correct expression. (This search could
4396 * be avoided, at the cost of complicating all the callers of this
4397 * routine; doesn't seem worth it.)
4398 */
4402
4405 {
4407 {
4411 }
4412 }
4416
4417 /*
4418 * Does it match the operand? Again, strip any relabeling.
4419 */
4422
4424 return true;
4425 }
4426
4427 return false;
4428}
References arg, elog, equal(), ERROR, fb(), i, IsA, lfirst, list_head(), lnext(), and strip_phvs_in_index_operand().
Referenced by ec_member_matches_indexcol(), expand_indexqual_rowcompare(), get_actual_variable_range(), group_similar_or_args(), match_boolean_index_clause(), match_clause_to_indexcol(), match_clause_to_ordering_op(), match_funcclause_to_indexcol(), match_opclause_to_indexcol(), match_orclause_to_indexcol(), match_rowcompare_to_indexcol(), match_saopclause_to_indexcol(), and relation_has_unique_index_for().
◆ match_join_clauses_to_index()
|
static |
Definition at line 2481 of file indxpath.c.
2485{
2487
2488 /* Scan the rel's join clauses */
2490 {
2492
2493 /* Check if clause can be moved to this rel */
2495 continue;
2496
2497 /*
2498 * Potentially usable, so see if it matches the index or is an OR. Use
2499 * list_append_unique_ptr() here to avoid possible duplicates when
2500 * processing the same clauses with different indexes.
2501 */
2504
2506 }
2507}
References fb(), join_clause_is_movable_to(), RelOptInfo::joininfo, lfirst, list_append_unique_ptr(), match_clause_to_index(), restriction_is_or_clause(), and root.
Referenced by create_index_paths().
◆ match_opclause_to_indexcol()
|
static |
Definition at line 2903 of file indxpath.c.
2907{
2911 *rightop;
2915 Oid opfamily;
2917
2918 /*
2919 * Only binary operators need apply. (In theory, a planner support
2920 * function could do something with a unary operator, but it seems
2921 * unlikely to be worth the cycles to check.)
2922 */
2925
2928 expr_op = clause->opno;
2929 expr_coll = clause->inputcollid;
2930
2932 opfamily = index->opfamily[indexcol];
2934
2935 /*
2936 * Check for clauses of the form: (indexkey operator constant) or
2937 * (constant operator indexkey). See match_clause_to_indexcol's notes
2938 * about const-ness.
2939 *
2940 * Note that we don't ask the support function about clauses that don't
2941 * have one of these forms. Again, in principle it might be possible to
2942 * do something, but it seems unlikely to be worth the cycles to check.
2943 */
2947 {
2950 {
2952 iclause->rinfo = rinfo;
2955 iclause->indexcol = indexcol;
2958 }
2959
2960 /*
2961 * If we didn't find a member of the index's opfamily, try the support
2962 * function for the operator's underlying function.
2963 */
2966 rinfo,
2967 clause->opfuncid,
2968 0, /* indexarg on left */
2969 indexcol,
2970 index);
2971 }
2972
2976 {
2978 {
2980
2983 {
2985
2986 /* Build a commuted OpExpr and RestrictInfo */
2988
2989 /* Make an IndexClause showing that as a derived qual */
2991 iclause->rinfo = rinfo;
2994 iclause->indexcol = indexcol;
2997 }
2998 }
2999
3000 /*
3001 * If we didn't find a member of the index's opfamily, try the support
3002 * function for the operator's underlying function.
3003 */
3006 rinfo,
3007 clause->opfuncid,
3008 1, /* indexarg on right */
3009 indexcol,
3010 index);
3011 }
3012
3014}
References OpExpr::args, bms_is_member(), RestrictInfo::clause, commute_restrictinfo(), contain_volatile_functions(), fb(), get_commutator(), get_index_clause_from_support(), IndexCollMatchesExprColl, linitial, list_length(), list_make1, lsecond, makeNode, match_index_to_operand(), NIL, OidIsValid, op_in_opfamily(), OpExpr::opno, root, and set_opfuncid().
Referenced by match_clause_to_indexcol().
◆ match_orclause_to_indexcol()
|
static |
Definition at line 3296 of file indxpath.c.
3300{
3314
3315 /* Forget it if index doesn't support SAOP clauses */
3318
3319 /*
3320 * Try to convert a list of OR-clauses to a single SAOP expression. Each
3321 * OR entry must be in the form: (indexkey operator constant) or (constant
3322 * operator indexkey). Operators of all the entries must match. On
3323 * discovery of anything unsupported, we give up by breaking out of the
3324 * loop immediately and returning NULL.
3325 */
3327 {
3330 Oid opno;
3332 *rightop;
3334
3335 /* If it's not a RestrictInfo (i.e. it's a sub-AND), we can't use it */
3337 break;
3338
3339 /* Only operator clauses can match */
3341 break;
3342
3344 opno = subClause->opno;
3345
3346 /* Only binary operators can match */
3348 break;
3349
3350 /*
3351 * Check for clauses of the form: (indexkey operator constant) or
3352 * (constant operator indexkey). These tests should agree with
3353 * match_opclause_to_indexcol.
3354 */
3360 {
3363 }
3367 {
3368 opno = get_commutator(opno);
3370 {
3371 /* commutator doesn't exist, we can't reverse the order */
3372 break;
3373 }
3376 }
3377 else
3378 {
3379 break;
3380 }
3381
3382 /*
3383 * Save information about the operator, type, and collation for the
3384 * first matching qual. Then, check that subsequent quals match the
3385 * first.
3386 */
3388 {
3389 matchOpno = opno;
3392 inputcollid = subClause->inputcollid;
3393
3394 /*
3395 * Check that the operator is presented in the opfamily and that
3396 * the expression collation matches the index collation. Also,
3397 * there must be an array type to construct an array later.
3398 */
3400 inputcollid) ||
3403 break;
3404
3405 /*
3406 * Disallow if either type is RECORD, mainly because we can't be
3407 * positive that all the RHS expressions are the same record type.
3408 */
3410 break;
3411
3413 }
3414 else
3415 {
3417 inputcollid != subClause->inputcollid ||
3419 break;
3420 }
3421
3422 /*
3423 * The righthand inputs don't necessarily have to be plain Consts, but
3424 * make_SAOP_expr needs to know if any are not.
3425 */
3428
3430 }
3431
3432 /*
3433 * Handle failed conversion from breaking out of the loop because of an
3434 * unsupported qual. Also check that we have an indexExpr, just in case
3435 * the OR list was somehow empty (it shouldn't be). Return NULL to
3436 * indicate the conversion failed.
3437 */
3439 {
3442 }
3443
3444 /*
3445 * Build the new SAOP node. We use the indexExpr from the last OR arm;
3446 * since all the arms passed match_index_to_operand, it shouldn't matter
3447 * which one we use. But using "inputcollid" twice is a bit of a cheat:
3448 * we might end up with an array Const node that is labeled with a
3449 * collation despite its elements being of a noncollatable type. But
3450 * nothing is likely to complain about that, so we don't bother being more
3451 * accurate.
3452 */
3456
3457 /*
3458 * Finally, build an IndexClause based on the SAOP node. It's not lossy.
3459 */
3461 iclause->rinfo = rinfo;
3465 iclause->indexcol = indexcol;
3468}
References Assert, bms_is_member(), contain_volatile_functions(), exprType(), fb(), get_array_type(), get_commutator(), IndexCollMatchesExprColl, InvalidOid, IsA, lappend(), lfirst, linitial, list_free(), list_length(), list_make1, lsecond, make_SAOP_expr(), make_simple_restrictinfo, makeNode, match_index_to_operand(), NIL, OidIsValid, op_in_opfamily(), and root.
Referenced by match_clause_to_indexcol().
◆ match_pathkeys_to_index()
|
static |
Definition at line 3716 of file indxpath.c.
3719{
3721
3724
3725 /* Only indexes with the amcanorderbyop property are interesting here */
3727 return;
3728
3730 {
3732 bool found = false;
3734 EquivalenceMember *member;
3735
3736
3737 /* Pathkey must request default sort order for the target opfamily */
3739 return;
3740
3741 /* If eclass is volatile, no hope of using an indexscan */
3743 return;
3744
3745 /*
3746 * Try to match eclass member expression(s) to index. Note that child
3747 * EC members are considered, but only when they belong to the target
3748 * relation. (Unlike regular members, the same expression could be a
3749 * child member of more than one EC. Therefore, the same index could
3750 * be considered to match more than one pathkey list, which is OK
3751 * here. See also get_eclass_for_sort_expr.)
3752 */
3754 index->rel->relids);
3756 {
3757 int indexcol;
3758
3759 /* No possibility of match if it references other relations */
3761 continue;
3762
3763 /*
3764 * We allow any column of the index to match each pathkey; they
3765 * don't have to match left-to-right as you might expect. This is
3766 * correct for GiST, and it doesn't matter for SP-GiST because
3767 * that doesn't handle multiple columns anyway, and no other
3768 * existing AMs support amcanorderbyop. We might need different
3769 * logic in future for other implementations.
3770 */
3772 {
3773 Expr *expr;
3774
3776 indexcol,
3777 member->em_expr,
3778 pathkey->pk_opfamily);
3779 if (expr)
3780 {
3783 found = true;
3784 break;
3785 }
3786 }
3787
3788 if (found) /* don't want to look at remaining members */
3789 break;
3790 }
3791
3792 /*
3793 * Return the matches found so far when this pathkey couldn't be
3794 * matched to the index.
3795 */
3796 if (!found)
3797 return;
3798 }
3799}
References bms_equal(), COMPARE_LT, eclass_member_iterator_next(), EquivalenceMember::em_expr, EquivalenceMember::em_relids, fb(), lappend(), lappend_int(), lfirst, match_clause_to_ordering_op(), NIL, and setup_eclass_member_iterator().
Referenced by build_index_paths().
◆ match_restriction_clauses_to_index()
|
static |
Definition at line 2465 of file indxpath.c.
2468{
2469 /* We can ignore clauses that are implied by the index predicate */
2471}
References fb(), match_clauses_to_index(), and root.
Referenced by create_index_paths().
◆ match_rowcompare_to_indexcol()
|
static |
Definition at line 3202 of file indxpath.c.
3206{
3209 Oid opfamily;
3212 *rightop;
3216
3217 /* Forget it if we're not dealing with a btree index */
3220
3222 opfamily = index->opfamily[indexcol];
3224
3225 /*
3226 * We could do the matching on the basis of insisting that the opfamily
3227 * shown in the RowCompareExpr be the same as the index column's opfamily,
3228 * but that could fail in the presence of reverse-sort opfamilies: it'd be
3229 * a matter of chance whether RowCompareExpr had picked the forward or
3230 * reverse-sort family. So look only at the operator, and match if it is
3231 * a member of the index's opfamily (after commutation, if the indexkey is
3232 * on the right). We'll worry later about whether any additional
3233 * operators are matchable to the index.
3234 */
3239
3240 /* Collations must match, if relevant */
3243
3244 /*
3245 * These syntactic tests are the same as in match_opclause_to_indexcol()
3246 */
3250 {
3251 /* OK, indexkey is on left */
3253 }
3257 {
3258 /* indexkey is on right, so commute the operator */
3263 }
3264 else
3266
3267 /* We're good if the operator is the right type of opfamily member */
3269 {
3275 rinfo,
3276 indexcol,
3277 index,
3278 expr_op,
3279 var_on_left);
3280 }
3281
3283}
References bms_is_member(), BTGreaterEqualStrategyNumber, BTGreaterStrategyNumber, BTLessEqualStrategyNumber, BTLessStrategyNumber, RestrictInfo::clause, contain_volatile_functions(), expand_indexqual_rowcompare(), fb(), get_commutator(), get_op_opfamily_strategy(), IndexCollMatchesExprColl, InvalidOid, RowCompareExpr::largs, linitial, linitial_oid, match_index_to_operand(), pull_varnos(), RowCompareExpr::rargs, and root.
Referenced by match_clause_to_indexcol().
◆ match_saopclause_to_indexcol()
|
static |
Definition at line 3134 of file indxpath.c.
3138{
3141 *rightop;
3146 Oid opfamily;
3148
3149 /* We only accept ANY clauses, not ALL */
3150 if (!saop->useOr)
3155 expr_op = saop->opno;
3156 expr_coll = saop->inputcollid;
3157
3159 opfamily = index->opfamily[indexcol];
3161
3162 /*
3163 * We must have indexkey on the left and a pseudo-constant array argument.
3164 */
3168 {
3171 {
3173
3174 iclause->rinfo = rinfo;
3177 iclause->indexcol = indexcol;
3180 }
3181
3182 /*
3183 * We do not currently ask support functions about ScalarArrayOpExprs,
3184 * though in principle we could.
3185 */
3186 }
3187
3189}
References ScalarArrayOpExpr::args, bms_is_member(), RestrictInfo::clause, contain_volatile_functions(), fb(), IndexCollMatchesExprColl, linitial, list_make1, lsecond, makeNode, match_index_to_operand(), NIL, op_in_opfamily(), ScalarArrayOpExpr::opno, pull_varnos(), root, and ScalarArrayOpExpr::useOr.
Referenced by match_clause_to_indexcol().
◆ or_arg_index_match_cmp()
Definition at line 1200 of file indxpath.c.
1201{
1204
1206 return -1;
1208 return 1;
1209
1211 return -1;
1213 return 1;
1214
1216 return -1;
1218 return 1;
1219
1221 return -1;
1223 return 1;
1224
1226 return -1;
1228 return 1;
1229
1230 return 0;
1231}
Referenced by group_similar_or_args().
◆ or_arg_index_match_cmp_group()
Definition at line 1238 of file indxpath.c.
1239{
1242
1244 return -1;
1246 return 1;
1247
1249 return -1;
1251 return 1;
1252
1253 return 0;
1254}
Referenced by group_similar_or_args().
◆ path_usage_comparator()
Definition at line 1990 of file indxpath.c.
1991{
1998
2001
2002 /*
2003 * If costs are the same, sort by selectivity.
2004 */
2006 return -1;
2008 return 1;
2009
2011 return -1;
2013 return 1;
2014
2015 return 0;
2016}
References a, b, cost_bitmap_tree_node(), and fb().
Referenced by choose_bitmap_and().
◆ relation_has_unique_index_for()
| bool relation_has_unique_index_for | ( | PlannerInfo * | root, |
| RelOptInfo * | rel, | ||
| List * | restrictlist, | ||
| List ** | extra_clauses | ||
| ) |
Definition at line 4145 of file indxpath.c.
4147{
4149
4150 /* Short-circuit if no indexes... */
4152 return false;
4153
4154 /*
4155 * Examine the rel's restriction clauses for usable var = const clauses
4156 * that we can add to the restrictlist.
4157 */
4159 {
4161
4162 /*
4163 * Note: can_join won't be set for a restriction clause, but
4164 * mergeopfamilies will be if it has a mergejoinable operator and
4165 * doesn't contain volatile functions.
4166 */
4168 continue; /* not mergejoinable */
4169
4170 /*
4171 * The clause certainly doesn't refer to anything but the given rel.
4172 * If either side is pseudoconstant then we can use it.
4173 */
4175 {
4176 /* righthand side is inner */
4178 }
4180 {
4181 /* lefthand side is inner */
4183 }
4184 else
4185 continue;
4186
4187 /* OK, add to list */
4189 }
4190
4191 /* Short-circuit the easy case */
4193 return false;
4194
4195 /* Examine each index of the relation ... */
4197 {
4201
4202 /*
4203 * If the index is not unique, or not immediately enforced, or if it's
4204 * a partial index, it's useless here. We're unable to make use of
4205 * predOK partial unique indexes due to the fact that
4206 * check_index_predicates() also makes use of join predicates to
4207 * determine if the partial index is usable. Here we need proofs that
4208 * hold true before any joins are evaluated.
4209 */
4211 continue;
4212
4213 /*
4214 * Try to find each index column in the list of conditions. This is
4215 * O(N^2) or worse, but we expect all the lists to be short.
4216 */
4218 {
4220
4222 {
4224 Node *rexpr;
4225
4226 /*
4227 * The condition's equality operator must be a member of the
4228 * index opfamily, else it is not asserting the right kind of
4229 * equality behavior for this index. We check this first
4230 * since it's probably cheaper than match_index_to_operand().
4231 */
4233 continue;
4234
4235 /*
4236 * XXX at some point we may need to check collations here too.
4237 * For the moment we assume all collations reduce to the same
4238 * notion of equality.
4239 */
4240
4241 /* OK, see if the condition operand matches the index key */
4242 if (rinfo->outer_is_left)
4244 else
4246
4248 {
4250 {
4253
4254 /*
4255 * Add filter clause into a list allowing caller to
4256 * know if uniqueness have made not only by join
4257 * clauses.
4258 */
4260 bms_is_empty(rinfo->right_relids));
4261 if (extra_clauses)
4262 exprs = lappend(exprs, rinfo);
4264 }
4265
4266 break; /* found a match; column is unique */
4267 }
4268 }
4269
4271 break; /* no match; this index doesn't help us */
4272 }
4273
4274 /* Matched all key columns of this index? */
4276 {
4277 if (extra_clauses)
4278 *extra_clauses = exprs;
4279 return true;
4280 }
4281 }
4282
4283 return false;
4284}
References Assert, RelOptInfo::baserestrictinfo, bms_is_empty, bms_membership(), BMS_SINGLETON, RestrictInfo::clause, fb(), get_leftop(), get_rightop(), RelOptInfo::indexlist, lappend(), lfirst, list_member_oid(), match_index_to_operand(), MemoryContextSwitchTo(), NIL, and root.
Referenced by rel_is_distinct_for().
◆ strip_phvs_in_index_operand()
Definition at line 4449 of file indxpath.c.
4450{
4451 /* Don't mutate/copy if no target PHVs exist */
4453 return operand;
4454
4456}
References contain_strippable_phv_walker(), fb(), and strip_phvs_in_index_operand_mutator().
Referenced by fix_indexqual_operand(), and match_index_to_operand().
◆ strip_phvs_in_index_operand_mutator()
Definition at line 4492 of file indxpath.c.
4493{
4496
4498 {
4500
4501 /* If matches the criteria, strip it */
4503 {
4504 /* Recurse on its contained expression */
4506 context);
4507 }
4508
4509 /* Otherwise, keep this PHV but check its contained expression */
4510 }
4511
4513 context);
4514}
References bms_is_empty, expression_tree_mutator, fb(), IsA, and strip_phvs_in_index_operand_mutator().
Referenced by strip_phvs_in_index_operand(), and strip_phvs_in_index_operand_mutator().
