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indxpath.c
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1 /*-------------------------------------------------------------------------
2  *
3  * indxpath.c
4  * Routines to determine which indexes are usable for scanning a
5  * given relation, and create Paths accordingly.
6  *
7  * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
8  * Portions Copyright (c) 1994, Regents of the University of California
9  *
10  *
11  * IDENTIFICATION
12  * src/backend/optimizer/path/indxpath.c
13  *
14  *-------------------------------------------------------------------------
15  */
16 #include "postgres.h"
17 
18 #include <math.h>
19 
20 #include "access/stratnum.h"
21 #include "access/sysattr.h"
22 #include "catalog/pg_am.h"
23 #include "catalog/pg_operator.h"
24 #include "catalog/pg_opfamily.h"
25 #include "catalog/pg_type.h"
26 #include "nodes/makefuncs.h"
27 #include "nodes/nodeFuncs.h"
28 #include "nodes/supportnodes.h"
29 #include "optimizer/cost.h"
30 #include "optimizer/optimizer.h"
31 #include "optimizer/pathnode.h"
32 #include "optimizer/paths.h"
33 #include "optimizer/prep.h"
34 #include "optimizer/restrictinfo.h"
35 #include "utils/lsyscache.h"
36 #include "utils/selfuncs.h"
37 
38 
39 /* XXX see PartCollMatchesExprColl */
40 #define IndexCollMatchesExprColl(idxcollation, exprcollation) \
41  ((idxcollation) == InvalidOid || (idxcollation) == (exprcollation))
42 
43 /* Whether we are looking for plain indexscan, bitmap scan, or either */
44 typedef enum
45 {
46  ST_INDEXSCAN, /* must support amgettuple */
47  ST_BITMAPSCAN, /* must support amgetbitmap */
48  ST_ANYSCAN, /* either is okay */
50 
51 /* Data structure for collecting qual clauses that match an index */
52 typedef struct
53 {
54  bool nonempty; /* True if lists are not all empty */
55  /* Lists of IndexClause nodes, one list per index column */
56  List *indexclauses[INDEX_MAX_KEYS];
58 
59 /* Per-path data used within choose_bitmap_and() */
60 typedef struct
61 {
62  Path *path; /* IndexPath, BitmapAndPath, or BitmapOrPath */
63  List *quals; /* the WHERE clauses it uses */
64  List *preds; /* predicates of its partial index(es) */
65  Bitmapset *clauseids; /* quals+preds represented as a bitmapset */
66  bool unclassifiable; /* has too many quals+preds to process? */
68 
69 /* Callback argument for ec_member_matches_indexcol */
70 typedef struct
71 {
72  IndexOptInfo *index; /* index we're considering */
73  int indexcol; /* index column we want to match to */
75 
76 
77 static void consider_index_join_clauses(PlannerInfo *root, RelOptInfo *rel,
79  IndexClauseSet *rclauseset,
80  IndexClauseSet *jclauseset,
81  IndexClauseSet *eclauseset,
82  List **bitindexpaths);
85  IndexClauseSet *rclauseset,
86  IndexClauseSet *jclauseset,
87  IndexClauseSet *eclauseset,
88  List **bitindexpaths,
89  List *indexjoinclauses,
90  int considered_clauses,
91  List **considered_relids);
92 static void get_join_index_paths(PlannerInfo *root, RelOptInfo *rel,
94  IndexClauseSet *rclauseset,
95  IndexClauseSet *jclauseset,
96  IndexClauseSet *eclauseset,
97  List **bitindexpaths,
98  Relids relids,
99  List **considered_relids);
100 static bool eclass_already_used(EquivalenceClass *parent_ec, Relids oldrelids,
101  List *indexjoinclauses);
102 static void get_index_paths(PlannerInfo *root, RelOptInfo *rel,
103  IndexOptInfo *index, IndexClauseSet *clauses,
104  List **bitindexpaths);
105 static List *build_index_paths(PlannerInfo *root, RelOptInfo *rel,
106  IndexOptInfo *index, IndexClauseSet *clauses,
107  bool useful_predicate,
108  ScanTypeControl scantype,
109  bool *skip_nonnative_saop,
110  bool *skip_lower_saop);
111 static List *build_paths_for_OR(PlannerInfo *root, RelOptInfo *rel,
112  List *clauses, List *other_clauses);
114  List *clauses, List *other_clauses);
115 static Path *choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel,
116  List *paths);
117 static int path_usage_comparator(const void *a, const void *b);
119  Path *ipath);
121  List *paths);
123  List **clauselist);
124 static void find_indexpath_quals(Path *bitmapqual, List **quals, List **preds);
125 static int find_list_position(Node *node, List **nodelist);
126 static bool check_index_only(RelOptInfo *rel, IndexOptInfo *index);
127 static double get_loop_count(PlannerInfo *root, Index cur_relid, Relids outer_relids);
128 static double adjust_rowcount_for_semijoins(PlannerInfo *root,
129  Index cur_relid,
130  Index outer_relid,
131  double rowcount);
132 static double approximate_joinrel_size(PlannerInfo *root, Relids relids);
135  IndexClauseSet *clauseset);
136 static void match_join_clauses_to_index(PlannerInfo *root,
138  IndexClauseSet *clauseset,
139  List **joinorclauses);
142  IndexClauseSet *clauseset);
143 static void match_clauses_to_index(PlannerInfo *root,
144  List *clauses,
146  IndexClauseSet *clauseset);
147 static void match_clause_to_index(PlannerInfo *root,
148  RestrictInfo *rinfo,
150  IndexClauseSet *clauseset);
152  RestrictInfo *rinfo,
153  int indexcol,
155 static bool IsBooleanOpfamily(Oid opfamily);
157  RestrictInfo *rinfo,
158  int indexcol, IndexOptInfo *index);
160  RestrictInfo *rinfo,
161  int indexcol,
164  RestrictInfo *rinfo,
165  int indexcol,
168  RestrictInfo *rinfo,
169  Oid funcid,
170  int indexarg,
171  int indexcol,
174  RestrictInfo *rinfo,
175  int indexcol,
178  RestrictInfo *rinfo,
179  int indexcol,
182  RestrictInfo *rinfo,
183  int indexcol,
185  Oid expr_op,
186  bool var_on_left);
187 static void match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys,
188  List **orderby_clauses_p,
189  List **clause_columns_p);
191  int indexcol, Expr *clause, Oid pk_opfamily);
192 static bool ec_member_matches_indexcol(PlannerInfo *root, RelOptInfo *rel,
194  void *arg);
195 
196 
197 /*
198  * create_index_paths()
199  * Generate all interesting index paths for the given relation.
200  * Candidate paths are added to the rel's pathlist (using add_path).
201  *
202  * To be considered for an index scan, an index must match one or more
203  * restriction clauses or join clauses from the query's qual condition,
204  * or match the query's ORDER BY condition, or have a predicate that
205  * matches the query's qual condition.
206  *
207  * There are two basic kinds of index scans. A "plain" index scan uses
208  * only restriction clauses (possibly none at all) in its indexqual,
209  * so it can be applied in any context. A "parameterized" index scan uses
210  * join clauses (plus restriction clauses, if available) in its indexqual.
211  * When joining such a scan to one of the relations supplying the other
212  * variables used in its indexqual, the parameterized scan must appear as
213  * the inner relation of a nestloop join; it can't be used on the outer side,
214  * nor in a merge or hash join. In that context, values for the other rels'
215  * attributes are available and fixed during any one scan of the indexpath.
216  *
217  * An IndexPath is generated and submitted to add_path() for each plain or
218  * parameterized index scan this routine deems potentially interesting for
219  * the current query.
220  *
221  * 'rel' is the relation for which we want to generate index paths
222  *
223  * Note: check_index_predicates() must have been run previously for this rel.
224  *
225  * Note: in cases involving LATERAL references in the relation's tlist, it's
226  * possible that rel->lateral_relids is nonempty. Currently, we include
227  * lateral_relids into the parameterization reported for each path, but don't
228  * take it into account otherwise. The fact that any such rels *must* be
229  * available as parameter sources perhaps should influence our choices of
230  * index quals ... but for now, it doesn't seem worth troubling over.
231  * In particular, comments below about "unparameterized" paths should be read
232  * as meaning "unparameterized so far as the indexquals are concerned".
233  */
234 void
236 {
237  List *indexpaths;
238  List *bitindexpaths;
239  List *bitjoinpaths;
240  List *joinorclauses;
241  IndexClauseSet rclauseset;
242  IndexClauseSet jclauseset;
243  IndexClauseSet eclauseset;
244  ListCell *lc;
245 
246  /* Skip the whole mess if no indexes */
247  if (rel->indexlist == NIL)
248  return;
249 
250  /* Bitmap paths are collected and then dealt with at the end */
251  bitindexpaths = bitjoinpaths = joinorclauses = NIL;
252 
253  /* Examine each index in turn */
254  foreach(lc, rel->indexlist)
255  {
257 
258  /* Protect limited-size array in IndexClauseSets */
259  Assert(index->nkeycolumns <= INDEX_MAX_KEYS);
260 
261  /*
262  * Ignore partial indexes that do not match the query.
263  * (generate_bitmap_or_paths() might be able to do something with
264  * them, but that's of no concern here.)
265  */
266  if (index->indpred != NIL && !index->predOK)
267  continue;
268 
269  /*
270  * Identify the restriction clauses that can match the index.
271  */
272  MemSet(&rclauseset, 0, sizeof(rclauseset));
273  match_restriction_clauses_to_index(root, index, &rclauseset);
274 
275  /*
276  * Build index paths from the restriction clauses. These will be
277  * non-parameterized paths. Plain paths go directly to add_path(),
278  * bitmap paths are added to bitindexpaths to be handled below.
279  */
280  get_index_paths(root, rel, index, &rclauseset,
281  &bitindexpaths);
282 
283  /*
284  * Identify the join clauses that can match the index. For the moment
285  * we keep them separate from the restriction clauses. Note that this
286  * step finds only "loose" join clauses that have not been merged into
287  * EquivalenceClasses. Also, collect join OR clauses for later.
288  */
289  MemSet(&jclauseset, 0, sizeof(jclauseset));
291  &jclauseset, &joinorclauses);
292 
293  /*
294  * Look for EquivalenceClasses that can generate joinclauses matching
295  * the index.
296  */
297  MemSet(&eclauseset, 0, sizeof(eclauseset));
299  &eclauseset);
300 
301  /*
302  * If we found any plain or eclass join clauses, build parameterized
303  * index paths using them.
304  */
305  if (jclauseset.nonempty || eclauseset.nonempty)
307  &rclauseset,
308  &jclauseset,
309  &eclauseset,
310  &bitjoinpaths);
311  }
312 
313  /*
314  * Generate BitmapOrPaths for any suitable OR-clauses present in the
315  * restriction list. Add these to bitindexpaths.
316  */
317  indexpaths = generate_bitmap_or_paths(root, rel,
318  rel->baserestrictinfo, NIL);
319  bitindexpaths = list_concat(bitindexpaths, indexpaths);
320 
321  /*
322  * Likewise, generate BitmapOrPaths for any suitable OR-clauses present in
323  * the joinclause list. Add these to bitjoinpaths.
324  */
325  indexpaths = generate_bitmap_or_paths(root, rel,
326  joinorclauses, rel->baserestrictinfo);
327  bitjoinpaths = list_concat(bitjoinpaths, indexpaths);
328 
329  /*
330  * If we found anything usable, generate a BitmapHeapPath for the most
331  * promising combination of restriction bitmap index paths. Note there
332  * will be only one such path no matter how many indexes exist. This
333  * should be sufficient since there's basically only one figure of merit
334  * (total cost) for such a path.
335  */
336  if (bitindexpaths != NIL)
337  {
338  Path *bitmapqual;
339  BitmapHeapPath *bpath;
340 
341  bitmapqual = choose_bitmap_and(root, rel, bitindexpaths);
342  bpath = create_bitmap_heap_path(root, rel, bitmapqual,
343  rel->lateral_relids, 1.0, 0);
344  add_path(rel, (Path *) bpath);
345 
346  /* create a partial bitmap heap path */
347  if (rel->consider_parallel && rel->lateral_relids == NULL)
348  create_partial_bitmap_paths(root, rel, bitmapqual);
349  }
350 
351  /*
352  * Likewise, if we found anything usable, generate BitmapHeapPaths for the
353  * most promising combinations of join bitmap index paths. Our strategy
354  * is to generate one such path for each distinct parameterization seen
355  * among the available bitmap index paths. This may look pretty
356  * expensive, but usually there won't be very many distinct
357  * parameterizations. (This logic is quite similar to that in
358  * consider_index_join_clauses, but we're working with whole paths not
359  * individual clauses.)
360  */
361  if (bitjoinpaths != NIL)
362  {
363  List *all_path_outers;
364 
365  /* Identify each distinct parameterization seen in bitjoinpaths */
366  all_path_outers = NIL;
367  foreach(lc, bitjoinpaths)
368  {
369  Path *path = (Path *) lfirst(lc);
370  Relids required_outer = PATH_REQ_OUTER(path);
371 
372  all_path_outers = list_append_unique(all_path_outers,
373  required_outer);
374  }
375 
376  /* Now, for each distinct parameterization set ... */
377  foreach(lc, all_path_outers)
378  {
379  Relids max_outers = (Relids) lfirst(lc);
380  List *this_path_set;
381  Path *bitmapqual;
382  Relids required_outer;
383  double loop_count;
384  BitmapHeapPath *bpath;
385  ListCell *lcp;
386 
387  /* Identify all the bitmap join paths needing no more than that */
388  this_path_set = NIL;
389  foreach(lcp, bitjoinpaths)
390  {
391  Path *path = (Path *) lfirst(lcp);
392 
393  if (bms_is_subset(PATH_REQ_OUTER(path), max_outers))
394  this_path_set = lappend(this_path_set, path);
395  }
396 
397  /*
398  * Add in restriction bitmap paths, since they can be used
399  * together with any join paths.
400  */
401  this_path_set = list_concat(this_path_set, bitindexpaths);
402 
403  /* Select best AND combination for this parameterization */
404  bitmapqual = choose_bitmap_and(root, rel, this_path_set);
405 
406  /* And push that path into the mix */
407  required_outer = PATH_REQ_OUTER(bitmapqual);
408  loop_count = get_loop_count(root, rel->relid, required_outer);
409  bpath = create_bitmap_heap_path(root, rel, bitmapqual,
410  required_outer, loop_count, 0);
411  add_path(rel, (Path *) bpath);
412  }
413  }
414 }
415 
416 /*
417  * consider_index_join_clauses
418  * Given sets of join clauses for an index, decide which parameterized
419  * index paths to build.
420  *
421  * Plain indexpaths are sent directly to add_path, while potential
422  * bitmap indexpaths are added to *bitindexpaths for later processing.
423  *
424  * 'rel' is the index's heap relation
425  * 'index' is the index for which we want to generate paths
426  * 'rclauseset' is the collection of indexable restriction clauses
427  * 'jclauseset' is the collection of indexable simple join clauses
428  * 'eclauseset' is the collection of indexable clauses from EquivalenceClasses
429  * '*bitindexpaths' is the list to add bitmap paths to
430  */
431 static void
434  IndexClauseSet *rclauseset,
435  IndexClauseSet *jclauseset,
436  IndexClauseSet *eclauseset,
437  List **bitindexpaths)
438 {
439  int considered_clauses = 0;
440  List *considered_relids = NIL;
441  int indexcol;
442 
443  /*
444  * The strategy here is to identify every potentially useful set of outer
445  * rels that can provide indexable join clauses. For each such set,
446  * select all the join clauses available from those outer rels, add on all
447  * the indexable restriction clauses, and generate plain and/or bitmap
448  * index paths for that set of clauses. This is based on the assumption
449  * that it's always better to apply a clause as an indexqual than as a
450  * filter (qpqual); which is where an available clause would end up being
451  * applied if we omit it from the indexquals.
452  *
453  * This looks expensive, but in most practical cases there won't be very
454  * many distinct sets of outer rels to consider. As a safety valve when
455  * that's not true, we use a heuristic: limit the number of outer rel sets
456  * considered to a multiple of the number of clauses considered. (We'll
457  * always consider using each individual join clause, though.)
458  *
459  * For simplicity in selecting relevant clauses, we represent each set of
460  * outer rels as a maximum set of clause_relids --- that is, the indexed
461  * relation itself is also included in the relids set. considered_relids
462  * lists all relids sets we've already tried.
463  */
464  for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
465  {
466  /* Consider each applicable simple join clause */
467  considered_clauses += list_length(jclauseset->indexclauses[indexcol]);
469  rclauseset, jclauseset, eclauseset,
470  bitindexpaths,
471  jclauseset->indexclauses[indexcol],
472  considered_clauses,
473  &considered_relids);
474  /* Consider each applicable eclass join clause */
475  considered_clauses += list_length(eclauseset->indexclauses[indexcol]);
477  rclauseset, jclauseset, eclauseset,
478  bitindexpaths,
479  eclauseset->indexclauses[indexcol],
480  considered_clauses,
481  &considered_relids);
482  }
483 }
484 
485 /*
486  * consider_index_join_outer_rels
487  * Generate parameterized paths based on clause relids in the clause list.
488  *
489  * Workhorse for consider_index_join_clauses; see notes therein for rationale.
490  *
491  * 'rel', 'index', 'rclauseset', 'jclauseset', 'eclauseset', and
492  * 'bitindexpaths' as above
493  * 'indexjoinclauses' is a list of IndexClauses for join clauses
494  * 'considered_clauses' is the total number of clauses considered (so far)
495  * '*considered_relids' is a list of all relids sets already considered
496  */
497 static void
500  IndexClauseSet *rclauseset,
501  IndexClauseSet *jclauseset,
502  IndexClauseSet *eclauseset,
503  List **bitindexpaths,
504  List *indexjoinclauses,
505  int considered_clauses,
506  List **considered_relids)
507 {
508  ListCell *lc;
509 
510  /* Examine relids of each joinclause in the given list */
511  foreach(lc, indexjoinclauses)
512  {
513  IndexClause *iclause = (IndexClause *) lfirst(lc);
514  Relids clause_relids = iclause->rinfo->clause_relids;
515  EquivalenceClass *parent_ec = iclause->rinfo->parent_ec;
516  int num_considered_relids;
517 
518  /* If we already tried its relids set, no need to do so again */
519  if (list_member(*considered_relids, clause_relids))
520  continue;
521 
522  /*
523  * Generate the union of this clause's relids set with each
524  * previously-tried set. This ensures we try this clause along with
525  * every interesting subset of previous clauses. However, to avoid
526  * exponential growth of planning time when there are many clauses,
527  * limit the number of relid sets accepted to 10 * considered_clauses.
528  *
529  * Note: get_join_index_paths appends entries to *considered_relids,
530  * but we do not need to visit such newly-added entries within this
531  * loop, so we don't use foreach() here. No real harm would be done
532  * if we did visit them, since the subset check would reject them; but
533  * it would waste some cycles.
534  */
535  num_considered_relids = list_length(*considered_relids);
536  for (int pos = 0; pos < num_considered_relids; pos++)
537  {
538  Relids oldrelids = (Relids) list_nth(*considered_relids, pos);
539 
540  /*
541  * If either is a subset of the other, no new set is possible.
542  * This isn't a complete test for redundancy, but it's easy and
543  * cheap. get_join_index_paths will check more carefully if we
544  * already generated the same relids set.
545  */
546  if (bms_subset_compare(clause_relids, oldrelids) != BMS_DIFFERENT)
547  continue;
548 
549  /*
550  * If this clause was derived from an equivalence class, the
551  * clause list may contain other clauses derived from the same
552  * eclass. We should not consider that combining this clause with
553  * one of those clauses generates a usefully different
554  * parameterization; so skip if any clause derived from the same
555  * eclass would already have been included when using oldrelids.
556  */
557  if (parent_ec &&
558  eclass_already_used(parent_ec, oldrelids,
559  indexjoinclauses))
560  continue;
561 
562  /*
563  * If the number of relid sets considered exceeds our heuristic
564  * limit, stop considering combinations of clauses. We'll still
565  * consider the current clause alone, though (below this loop).
566  */
567  if (list_length(*considered_relids) >= 10 * considered_clauses)
568  break;
569 
570  /* OK, try the union set */
571  get_join_index_paths(root, rel, index,
572  rclauseset, jclauseset, eclauseset,
573  bitindexpaths,
574  bms_union(clause_relids, oldrelids),
575  considered_relids);
576  }
577 
578  /* Also try this set of relids by itself */
579  get_join_index_paths(root, rel, index,
580  rclauseset, jclauseset, eclauseset,
581  bitindexpaths,
582  clause_relids,
583  considered_relids);
584  }
585 }
586 
587 /*
588  * get_join_index_paths
589  * Generate index paths using clauses from the specified outer relations.
590  * In addition to generating paths, relids is added to *considered_relids
591  * if not already present.
592  *
593  * Workhorse for consider_index_join_clauses; see notes therein for rationale.
594  *
595  * 'rel', 'index', 'rclauseset', 'jclauseset', 'eclauseset',
596  * 'bitindexpaths', 'considered_relids' as above
597  * 'relids' is the current set of relids to consider (the target rel plus
598  * one or more outer rels)
599  */
600 static void
603  IndexClauseSet *rclauseset,
604  IndexClauseSet *jclauseset,
605  IndexClauseSet *eclauseset,
606  List **bitindexpaths,
607  Relids relids,
608  List **considered_relids)
609 {
610  IndexClauseSet clauseset;
611  int indexcol;
612 
613  /* If we already considered this relids set, don't repeat the work */
614  if (list_member(*considered_relids, relids))
615  return;
616 
617  /* Identify indexclauses usable with this relids set */
618  MemSet(&clauseset, 0, sizeof(clauseset));
619 
620  for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
621  {
622  ListCell *lc;
623 
624  /* First find applicable simple join clauses */
625  foreach(lc, jclauseset->indexclauses[indexcol])
626  {
627  IndexClause *iclause = (IndexClause *) lfirst(lc);
628 
629  if (bms_is_subset(iclause->rinfo->clause_relids, relids))
630  clauseset.indexclauses[indexcol] =
631  lappend(clauseset.indexclauses[indexcol], iclause);
632  }
633 
634  /*
635  * Add applicable eclass join clauses. The clauses generated for each
636  * column are redundant (cf generate_implied_equalities_for_column),
637  * so we need at most one. This is the only exception to the general
638  * rule of using all available index clauses.
639  */
640  foreach(lc, eclauseset->indexclauses[indexcol])
641  {
642  IndexClause *iclause = (IndexClause *) lfirst(lc);
643 
644  if (bms_is_subset(iclause->rinfo->clause_relids, relids))
645  {
646  clauseset.indexclauses[indexcol] =
647  lappend(clauseset.indexclauses[indexcol], iclause);
648  break;
649  }
650  }
651 
652  /* Add restriction clauses */
653  clauseset.indexclauses[indexcol] =
654  list_concat(clauseset.indexclauses[indexcol],
655  rclauseset->indexclauses[indexcol]);
656 
657  if (clauseset.indexclauses[indexcol] != NIL)
658  clauseset.nonempty = true;
659  }
660 
661  /* We should have found something, else caller passed silly relids */
662  Assert(clauseset.nonempty);
663 
664  /* Build index path(s) using the collected set of clauses */
665  get_index_paths(root, rel, index, &clauseset, bitindexpaths);
666 
667  /*
668  * Remember we considered paths for this set of relids.
669  */
670  *considered_relids = lappend(*considered_relids, relids);
671 }
672 
673 /*
674  * eclass_already_used
675  * True if any join clause usable with oldrelids was generated from
676  * the specified equivalence class.
677  */
678 static bool
680  List *indexjoinclauses)
681 {
682  ListCell *lc;
683 
684  foreach(lc, indexjoinclauses)
685  {
686  IndexClause *iclause = (IndexClause *) lfirst(lc);
687  RestrictInfo *rinfo = iclause->rinfo;
688 
689  if (rinfo->parent_ec == parent_ec &&
690  bms_is_subset(rinfo->clause_relids, oldrelids))
691  return true;
692  }
693  return false;
694 }
695 
696 
697 /*
698  * get_index_paths
699  * Given an index and a set of index clauses for it, construct IndexPaths.
700  *
701  * Plain indexpaths are sent directly to add_path, while potential
702  * bitmap indexpaths are added to *bitindexpaths for later processing.
703  *
704  * This is a fairly simple frontend to build_index_paths(). Its reason for
705  * existence is mainly to handle ScalarArrayOpExpr quals properly. If the
706  * index AM supports them natively, we should just include them in simple
707  * index paths. If not, we should exclude them while building simple index
708  * paths, and then make a separate attempt to include them in bitmap paths.
709  * Furthermore, we should consider excluding lower-order ScalarArrayOpExpr
710  * quals so as to create ordered paths.
711  */
712 static void
714  IndexOptInfo *index, IndexClauseSet *clauses,
715  List **bitindexpaths)
716 {
717  List *indexpaths;
718  bool skip_nonnative_saop = false;
719  bool skip_lower_saop = false;
720  ListCell *lc;
721 
722  /*
723  * Build simple index paths using the clauses. Allow ScalarArrayOpExpr
724  * clauses only if the index AM supports them natively, and skip any such
725  * clauses for index columns after the first (so that we produce ordered
726  * paths if possible).
727  */
728  indexpaths = build_index_paths(root, rel,
729  index, clauses,
730  index->predOK,
731  ST_ANYSCAN,
732  &skip_nonnative_saop,
733  &skip_lower_saop);
734 
735  /*
736  * If we skipped any lower-order ScalarArrayOpExprs on an index with an AM
737  * that supports them, then try again including those clauses. This will
738  * produce paths with more selectivity but no ordering.
739  */
740  if (skip_lower_saop)
741  {
742  indexpaths = list_concat(indexpaths,
743  build_index_paths(root, rel,
744  index, clauses,
745  index->predOK,
746  ST_ANYSCAN,
747  &skip_nonnative_saop,
748  NULL));
749  }
750 
751  /*
752  * Submit all the ones that can form plain IndexScan plans to add_path. (A
753  * plain IndexPath can represent either a plain IndexScan or an
754  * IndexOnlyScan, but for our purposes here that distinction does not
755  * matter. However, some of the indexes might support only bitmap scans,
756  * and those we mustn't submit to add_path here.)
757  *
758  * Also, pick out the ones that are usable as bitmap scans. For that, we
759  * must discard indexes that don't support bitmap scans, and we also are
760  * only interested in paths that have some selectivity; we should discard
761  * anything that was generated solely for ordering purposes.
762  */
763  foreach(lc, indexpaths)
764  {
765  IndexPath *ipath = (IndexPath *) lfirst(lc);
766 
767  if (index->amhasgettuple)
768  add_path(rel, (Path *) ipath);
769 
770  if (index->amhasgetbitmap &&
771  (ipath->path.pathkeys == NIL ||
772  ipath->indexselectivity < 1.0))
773  *bitindexpaths = lappend(*bitindexpaths, ipath);
774  }
775 
776  /*
777  * If there were ScalarArrayOpExpr clauses that the index can't handle
778  * natively, generate bitmap scan paths relying on executor-managed
779  * ScalarArrayOpExpr.
780  */
781  if (skip_nonnative_saop)
782  {
783  indexpaths = build_index_paths(root, rel,
784  index, clauses,
785  false,
787  NULL,
788  NULL);
789  *bitindexpaths = list_concat(*bitindexpaths, indexpaths);
790  }
791 }
792 
793 /*
794  * build_index_paths
795  * Given an index and a set of index clauses for it, construct zero
796  * or more IndexPaths. It also constructs zero or more partial IndexPaths.
797  *
798  * We return a list of paths because (1) this routine checks some cases
799  * that should cause us to not generate any IndexPath, and (2) in some
800  * cases we want to consider both a forward and a backward scan, so as
801  * to obtain both sort orders. Note that the paths are just returned
802  * to the caller and not immediately fed to add_path().
803  *
804  * At top level, useful_predicate should be exactly the index's predOK flag
805  * (ie, true if it has a predicate that was proven from the restriction
806  * clauses). When working on an arm of an OR clause, useful_predicate
807  * should be true if the predicate required the current OR list to be proven.
808  * Note that this routine should never be called at all if the index has an
809  * unprovable predicate.
810  *
811  * scantype indicates whether we want to create plain indexscans, bitmap
812  * indexscans, or both. When it's ST_BITMAPSCAN, we will not consider
813  * index ordering while deciding if a Path is worth generating.
814  *
815  * If skip_nonnative_saop is non-NULL, we ignore ScalarArrayOpExpr clauses
816  * unless the index AM supports them directly, and we set *skip_nonnative_saop
817  * to true if we found any such clauses (caller must initialize the variable
818  * to false). If it's NULL, we do not ignore ScalarArrayOpExpr clauses.
819  *
820  * If skip_lower_saop is non-NULL, we ignore ScalarArrayOpExpr clauses for
821  * non-first index columns, and we set *skip_lower_saop to true if we found
822  * any such clauses (caller must initialize the variable to false). If it's
823  * NULL, we do not ignore non-first ScalarArrayOpExpr clauses, but they will
824  * result in considering the scan's output to be unordered.
825  *
826  * 'rel' is the index's heap relation
827  * 'index' is the index for which we want to generate paths
828  * 'clauses' is the collection of indexable clauses (IndexClause nodes)
829  * 'useful_predicate' indicates whether the index has a useful predicate
830  * 'scantype' indicates whether we need plain or bitmap scan support
831  * 'skip_nonnative_saop' indicates whether to accept SAOP if index AM doesn't
832  * 'skip_lower_saop' indicates whether to accept non-first-column SAOP
833  */
834 static List *
836  IndexOptInfo *index, IndexClauseSet *clauses,
837  bool useful_predicate,
838  ScanTypeControl scantype,
839  bool *skip_nonnative_saop,
840  bool *skip_lower_saop)
841 {
842  List *result = NIL;
843  IndexPath *ipath;
844  List *index_clauses;
845  Relids outer_relids;
846  double loop_count;
847  List *orderbyclauses;
848  List *orderbyclausecols;
849  List *index_pathkeys;
850  List *useful_pathkeys;
851  bool found_lower_saop_clause;
852  bool pathkeys_possibly_useful;
853  bool index_is_ordered;
854  bool index_only_scan;
855  int indexcol;
856 
857  /*
858  * Check that index supports the desired scan type(s)
859  */
860  switch (scantype)
861  {
862  case ST_INDEXSCAN:
863  if (!index->amhasgettuple)
864  return NIL;
865  break;
866  case ST_BITMAPSCAN:
867  if (!index->amhasgetbitmap)
868  return NIL;
869  break;
870  case ST_ANYSCAN:
871  /* either or both are OK */
872  break;
873  }
874 
875  /*
876  * 1. Combine the per-column IndexClause lists into an overall list.
877  *
878  * In the resulting list, clauses are ordered by index key, so that the
879  * column numbers form a nondecreasing sequence. (This order is depended
880  * on by btree and possibly other places.) The list can be empty, if the
881  * index AM allows that.
882  *
883  * found_lower_saop_clause is set true if we accept a ScalarArrayOpExpr
884  * index clause for a non-first index column. This prevents us from
885  * assuming that the scan result is ordered. (Actually, the result is
886  * still ordered if there are equality constraints for all earlier
887  * columns, but it seems too expensive and non-modular for this code to be
888  * aware of that refinement.)
889  *
890  * We also build a Relids set showing which outer rels are required by the
891  * selected clauses. Any lateral_relids are included in that, but not
892  * otherwise accounted for.
893  */
894  index_clauses = NIL;
895  found_lower_saop_clause = false;
896  outer_relids = bms_copy(rel->lateral_relids);
897  for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
898  {
899  ListCell *lc;
900 
901  foreach(lc, clauses->indexclauses[indexcol])
902  {
903  IndexClause *iclause = (IndexClause *) lfirst(lc);
904  RestrictInfo *rinfo = iclause->rinfo;
905 
906  /* We might need to omit ScalarArrayOpExpr clauses */
907  if (IsA(rinfo->clause, ScalarArrayOpExpr))
908  {
909  if (!index->amsearcharray)
910  {
911  if (skip_nonnative_saop)
912  {
913  /* Ignore because not supported by index */
914  *skip_nonnative_saop = true;
915  continue;
916  }
917  /* Caller had better intend this only for bitmap scan */
918  Assert(scantype == ST_BITMAPSCAN);
919  }
920  if (indexcol > 0)
921  {
922  if (skip_lower_saop)
923  {
924  /* Caller doesn't want to lose index ordering */
925  *skip_lower_saop = true;
926  continue;
927  }
928  found_lower_saop_clause = true;
929  }
930  }
931 
932  /* OK to include this clause */
933  index_clauses = lappend(index_clauses, iclause);
934  outer_relids = bms_add_members(outer_relids,
935  rinfo->clause_relids);
936  }
937 
938  /*
939  * If no clauses match the first index column, check for amoptionalkey
940  * restriction. We can't generate a scan over an index with
941  * amoptionalkey = false unless there's at least one index clause.
942  * (When working on columns after the first, this test cannot fail. It
943  * is always okay for columns after the first to not have any
944  * clauses.)
945  */
946  if (index_clauses == NIL && !index->amoptionalkey)
947  return NIL;
948  }
949 
950  /* We do not want the index's rel itself listed in outer_relids */
951  outer_relids = bms_del_member(outer_relids, rel->relid);
952 
953  /* Compute loop_count for cost estimation purposes */
954  loop_count = get_loop_count(root, rel->relid, outer_relids);
955 
956  /*
957  * 2. Compute pathkeys describing index's ordering, if any, then see how
958  * many of them are actually useful for this query. This is not relevant
959  * if we are only trying to build bitmap indexscans, nor if we have to
960  * assume the scan is unordered.
961  */
962  pathkeys_possibly_useful = (scantype != ST_BITMAPSCAN &&
963  !found_lower_saop_clause &&
964  has_useful_pathkeys(root, rel));
965  index_is_ordered = (index->sortopfamily != NULL);
966  if (index_is_ordered && pathkeys_possibly_useful)
967  {
968  index_pathkeys = build_index_pathkeys(root, index,
970  useful_pathkeys = truncate_useless_pathkeys(root, rel,
971  index_pathkeys);
972  orderbyclauses = NIL;
973  orderbyclausecols = NIL;
974  }
975  else if (index->amcanorderbyop && pathkeys_possibly_useful)
976  {
977  /*
978  * See if we can generate ordering operators for query_pathkeys or at
979  * least some prefix thereof. Matching to just a prefix of the
980  * query_pathkeys will allow an incremental sort to be considered on
981  * the index's partially sorted results.
982  */
984  &orderbyclauses,
985  &orderbyclausecols);
986  if (list_length(root->query_pathkeys) == list_length(orderbyclauses))
987  useful_pathkeys = root->query_pathkeys;
988  else
989  useful_pathkeys = list_copy_head(root->query_pathkeys,
990  list_length(orderbyclauses));
991  }
992  else
993  {
994  useful_pathkeys = NIL;
995  orderbyclauses = NIL;
996  orderbyclausecols = NIL;
997  }
998 
999  /*
1000  * 3. Check if an index-only scan is possible. If we're not building
1001  * plain indexscans, this isn't relevant since bitmap scans don't support
1002  * index data retrieval anyway.
1003  */
1004  index_only_scan = (scantype != ST_BITMAPSCAN &&
1005  check_index_only(rel, index));
1006 
1007  /*
1008  * 4. Generate an indexscan path if there are relevant restriction clauses
1009  * in the current clauses, OR the index ordering is potentially useful for
1010  * later merging or final output ordering, OR the index has a useful
1011  * predicate, OR an index-only scan is possible.
1012  */
1013  if (index_clauses != NIL || useful_pathkeys != NIL || useful_predicate ||
1014  index_only_scan)
1015  {
1016  ipath = create_index_path(root, index,
1017  index_clauses,
1018  orderbyclauses,
1019  orderbyclausecols,
1020  useful_pathkeys,
1022  index_only_scan,
1023  outer_relids,
1024  loop_count,
1025  false);
1026  result = lappend(result, ipath);
1027 
1028  /*
1029  * If appropriate, consider parallel index scan. We don't allow
1030  * parallel index scan for bitmap index scans.
1031  */
1032  if (index->amcanparallel &&
1033  rel->consider_parallel && outer_relids == NULL &&
1034  scantype != ST_BITMAPSCAN)
1035  {
1036  ipath = create_index_path(root, index,
1037  index_clauses,
1038  orderbyclauses,
1039  orderbyclausecols,
1040  useful_pathkeys,
1042  index_only_scan,
1043  outer_relids,
1044  loop_count,
1045  true);
1046 
1047  /*
1048  * if, after costing the path, we find that it's not worth using
1049  * parallel workers, just free it.
1050  */
1051  if (ipath->path.parallel_workers > 0)
1052  add_partial_path(rel, (Path *) ipath);
1053  else
1054  pfree(ipath);
1055  }
1056  }
1057 
1058  /*
1059  * 5. If the index is ordered, a backwards scan might be interesting.
1060  */
1061  if (index_is_ordered && pathkeys_possibly_useful)
1062  {
1063  index_pathkeys = build_index_pathkeys(root, index,
1065  useful_pathkeys = truncate_useless_pathkeys(root, rel,
1066  index_pathkeys);
1067  if (useful_pathkeys != NIL)
1068  {
1069  ipath = create_index_path(root, index,
1070  index_clauses,
1071  NIL,
1072  NIL,
1073  useful_pathkeys,
1075  index_only_scan,
1076  outer_relids,
1077  loop_count,
1078  false);
1079  result = lappend(result, ipath);
1080 
1081  /* If appropriate, consider parallel index scan */
1082  if (index->amcanparallel &&
1083  rel->consider_parallel && outer_relids == NULL &&
1084  scantype != ST_BITMAPSCAN)
1085  {
1086  ipath = create_index_path(root, index,
1087  index_clauses,
1088  NIL,
1089  NIL,
1090  useful_pathkeys,
1092  index_only_scan,
1093  outer_relids,
1094  loop_count,
1095  true);
1096 
1097  /*
1098  * if, after costing the path, we find that it's not worth
1099  * using parallel workers, just free it.
1100  */
1101  if (ipath->path.parallel_workers > 0)
1102  add_partial_path(rel, (Path *) ipath);
1103  else
1104  pfree(ipath);
1105  }
1106  }
1107  }
1108 
1109  return result;
1110 }
1111 
1112 /*
1113  * build_paths_for_OR
1114  * Given a list of restriction clauses from one arm of an OR clause,
1115  * construct all matching IndexPaths for the relation.
1116  *
1117  * Here we must scan all indexes of the relation, since a bitmap OR tree
1118  * can use multiple indexes.
1119  *
1120  * The caller actually supplies two lists of restriction clauses: some
1121  * "current" ones and some "other" ones. Both lists can be used freely
1122  * to match keys of the index, but an index must use at least one of the
1123  * "current" clauses to be considered usable. The motivation for this is
1124  * examples like
1125  * WHERE (x = 42) AND (... OR (y = 52 AND z = 77) OR ....)
1126  * While we are considering the y/z subclause of the OR, we can use "x = 42"
1127  * as one of the available index conditions; but we shouldn't match the
1128  * subclause to any index on x alone, because such a Path would already have
1129  * been generated at the upper level. So we could use an index on x,y,z
1130  * or an index on x,y for the OR subclause, but not an index on just x.
1131  * When dealing with a partial index, a match of the index predicate to
1132  * one of the "current" clauses also makes the index usable.
1133  *
1134  * 'rel' is the relation for which we want to generate index paths
1135  * 'clauses' is the current list of clauses (RestrictInfo nodes)
1136  * 'other_clauses' is the list of additional upper-level clauses
1137  */
1138 static List *
1140  List *clauses, List *other_clauses)
1141 {
1142  List *result = NIL;
1143  List *all_clauses = NIL; /* not computed till needed */
1144  ListCell *lc;
1145 
1146  foreach(lc, rel->indexlist)
1147  {
1149  IndexClauseSet clauseset;
1150  List *indexpaths;
1151  bool useful_predicate;
1152 
1153  /* Ignore index if it doesn't support bitmap scans */
1154  if (!index->amhasgetbitmap)
1155  continue;
1156 
1157  /*
1158  * Ignore partial indexes that do not match the query. If a partial
1159  * index is marked predOK then we know it's OK. Otherwise, we have to
1160  * test whether the added clauses are sufficient to imply the
1161  * predicate. If so, we can use the index in the current context.
1162  *
1163  * We set useful_predicate to true iff the predicate was proven using
1164  * the current set of clauses. This is needed to prevent matching a
1165  * predOK index to an arm of an OR, which would be a legal but
1166  * pointlessly inefficient plan. (A better plan will be generated by
1167  * just scanning the predOK index alone, no OR.)
1168  */
1169  useful_predicate = false;
1170  if (index->indpred != NIL)
1171  {
1172  if (index->predOK)
1173  {
1174  /* Usable, but don't set useful_predicate */
1175  }
1176  else
1177  {
1178  /* Form all_clauses if not done already */
1179  if (all_clauses == NIL)
1180  all_clauses = list_concat_copy(clauses, other_clauses);
1181 
1182  if (!predicate_implied_by(index->indpred, all_clauses, false))
1183  continue; /* can't use it at all */
1184 
1185  if (!predicate_implied_by(index->indpred, other_clauses, false))
1186  useful_predicate = true;
1187  }
1188  }
1189 
1190  /*
1191  * Identify the restriction clauses that can match the index.
1192  */
1193  MemSet(&clauseset, 0, sizeof(clauseset));
1194  match_clauses_to_index(root, clauses, index, &clauseset);
1195 
1196  /*
1197  * If no matches so far, and the index predicate isn't useful, we
1198  * don't want it.
1199  */
1200  if (!clauseset.nonempty && !useful_predicate)
1201  continue;
1202 
1203  /*
1204  * Add "other" restriction clauses to the clauseset.
1205  */
1206  match_clauses_to_index(root, other_clauses, index, &clauseset);
1207 
1208  /*
1209  * Construct paths if possible.
1210  */
1211  indexpaths = build_index_paths(root, rel,
1212  index, &clauseset,
1213  useful_predicate,
1214  ST_BITMAPSCAN,
1215  NULL,
1216  NULL);
1217  result = list_concat(result, indexpaths);
1218  }
1219 
1220  return result;
1221 }
1222 
1223 /*
1224  * generate_bitmap_or_paths
1225  * Look through the list of clauses to find OR clauses, and generate
1226  * a BitmapOrPath for each one we can handle that way. Return a list
1227  * of the generated BitmapOrPaths.
1228  *
1229  * other_clauses is a list of additional clauses that can be assumed true
1230  * for the purpose of generating indexquals, but are not to be searched for
1231  * ORs. (See build_paths_for_OR() for motivation.)
1232  */
1233 static List *
1235  List *clauses, List *other_clauses)
1236 {
1237  List *result = NIL;
1238  List *all_clauses;
1239  ListCell *lc;
1240 
1241  /*
1242  * We can use both the current and other clauses as context for
1243  * build_paths_for_OR; no need to remove ORs from the lists.
1244  */
1245  all_clauses = list_concat_copy(clauses, other_clauses);
1246 
1247  foreach(lc, clauses)
1248  {
1249  RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
1250  List *pathlist;
1251  Path *bitmapqual;
1252  ListCell *j;
1253 
1254  /* Ignore RestrictInfos that aren't ORs */
1255  if (!restriction_is_or_clause(rinfo))
1256  continue;
1257 
1258  /*
1259  * We must be able to match at least one index to each of the arms of
1260  * the OR, else we can't use it.
1261  */
1262  pathlist = NIL;
1263  foreach(j, ((BoolExpr *) rinfo->orclause)->args)
1264  {
1265  Node *orarg = (Node *) lfirst(j);
1266  List *indlist;
1267 
1268  /* OR arguments should be ANDs or sub-RestrictInfos */
1269  if (is_andclause(orarg))
1270  {
1271  List *andargs = ((BoolExpr *) orarg)->args;
1272 
1273  indlist = build_paths_for_OR(root, rel,
1274  andargs,
1275  all_clauses);
1276 
1277  /* Recurse in case there are sub-ORs */
1278  indlist = list_concat(indlist,
1279  generate_bitmap_or_paths(root, rel,
1280  andargs,
1281  all_clauses));
1282  }
1283  else
1284  {
1285  RestrictInfo *ri = castNode(RestrictInfo, orarg);
1286  List *orargs;
1287 
1289  orargs = list_make1(ri);
1290 
1291  indlist = build_paths_for_OR(root, rel,
1292  orargs,
1293  all_clauses);
1294  }
1295 
1296  /*
1297  * If nothing matched this arm, we can't do anything with this OR
1298  * clause.
1299  */
1300  if (indlist == NIL)
1301  {
1302  pathlist = NIL;
1303  break;
1304  }
1305 
1306  /*
1307  * OK, pick the most promising AND combination, and add it to
1308  * pathlist.
1309  */
1310  bitmapqual = choose_bitmap_and(root, rel, indlist);
1311  pathlist = lappend(pathlist, bitmapqual);
1312  }
1313 
1314  /*
1315  * If we have a match for every arm, then turn them into a
1316  * BitmapOrPath, and add to result list.
1317  */
1318  if (pathlist != NIL)
1319  {
1320  bitmapqual = (Path *) create_bitmap_or_path(root, rel, pathlist);
1321  result = lappend(result, bitmapqual);
1322  }
1323  }
1324 
1325  return result;
1326 }
1327 
1328 
1329 /*
1330  * choose_bitmap_and
1331  * Given a nonempty list of bitmap paths, AND them into one path.
1332  *
1333  * This is a nontrivial decision since we can legally use any subset of the
1334  * given path set. We want to choose a good tradeoff between selectivity
1335  * and cost of computing the bitmap.
1336  *
1337  * The result is either a single one of the inputs, or a BitmapAndPath
1338  * combining multiple inputs.
1339  */
1340 static Path *
1342 {
1343  int npaths = list_length(paths);
1344  PathClauseUsage **pathinfoarray;
1345  PathClauseUsage *pathinfo;
1346  List *clauselist;
1347  List *bestpaths = NIL;
1348  Cost bestcost = 0;
1349  int i,
1350  j;
1351  ListCell *l;
1352 
1353  Assert(npaths > 0); /* else caller error */
1354  if (npaths == 1)
1355  return (Path *) linitial(paths); /* easy case */
1356 
1357  /*
1358  * In theory we should consider every nonempty subset of the given paths.
1359  * In practice that seems like overkill, given the crude nature of the
1360  * estimates, not to mention the possible effects of higher-level AND and
1361  * OR clauses. Moreover, it's completely impractical if there are a large
1362  * number of paths, since the work would grow as O(2^N).
1363  *
1364  * As a heuristic, we first check for paths using exactly the same sets of
1365  * WHERE clauses + index predicate conditions, and reject all but the
1366  * cheapest-to-scan in any such group. This primarily gets rid of indexes
1367  * that include the interesting columns but also irrelevant columns. (In
1368  * situations where the DBA has gone overboard on creating variant
1369  * indexes, this can make for a very large reduction in the number of
1370  * paths considered further.)
1371  *
1372  * We then sort the surviving paths with the cheapest-to-scan first, and
1373  * for each path, consider using that path alone as the basis for a bitmap
1374  * scan. Then we consider bitmap AND scans formed from that path plus
1375  * each subsequent (higher-cost) path, adding on a subsequent path if it
1376  * results in a reduction in the estimated total scan cost. This means we
1377  * consider about O(N^2) rather than O(2^N) path combinations, which is
1378  * quite tolerable, especially given than N is usually reasonably small
1379  * because of the prefiltering step. The cheapest of these is returned.
1380  *
1381  * We will only consider AND combinations in which no two indexes use the
1382  * same WHERE clause. This is a bit of a kluge: it's needed because
1383  * costsize.c and clausesel.c aren't very smart about redundant clauses.
1384  * They will usually double-count the redundant clauses, producing a
1385  * too-small selectivity that makes a redundant AND step look like it
1386  * reduces the total cost. Perhaps someday that code will be smarter and
1387  * we can remove this limitation. (But note that this also defends
1388  * against flat-out duplicate input paths, which can happen because
1389  * match_join_clauses_to_index will find the same OR join clauses that
1390  * extract_restriction_or_clauses has pulled OR restriction clauses out
1391  * of.)
1392  *
1393  * For the same reason, we reject AND combinations in which an index
1394  * predicate clause duplicates another clause. Here we find it necessary
1395  * to be even stricter: we'll reject a partial index if any of its
1396  * predicate clauses are implied by the set of WHERE clauses and predicate
1397  * clauses used so far. This covers cases such as a condition "x = 42"
1398  * used with a plain index, followed by a clauseless scan of a partial
1399  * index "WHERE x >= 40 AND x < 50". The partial index has been accepted
1400  * only because "x = 42" was present, and so allowing it would partially
1401  * double-count selectivity. (We could use predicate_implied_by on
1402  * regular qual clauses too, to have a more intelligent, but much more
1403  * expensive, check for redundancy --- but in most cases simple equality
1404  * seems to suffice.)
1405  */
1406 
1407  /*
1408  * Extract clause usage info and detect any paths that use exactly the
1409  * same set of clauses; keep only the cheapest-to-scan of any such groups.
1410  * The surviving paths are put into an array for qsort'ing.
1411  */
1412  pathinfoarray = (PathClauseUsage **)
1413  palloc(npaths * sizeof(PathClauseUsage *));
1414  clauselist = NIL;
1415  npaths = 0;
1416  foreach(l, paths)
1417  {
1418  Path *ipath = (Path *) lfirst(l);
1419 
1420  pathinfo = classify_index_clause_usage(ipath, &clauselist);
1421 
1422  /* If it's unclassifiable, treat it as distinct from all others */
1423  if (pathinfo->unclassifiable)
1424  {
1425  pathinfoarray[npaths++] = pathinfo;
1426  continue;
1427  }
1428 
1429  for (i = 0; i < npaths; i++)
1430  {
1431  if (!pathinfoarray[i]->unclassifiable &&
1432  bms_equal(pathinfo->clauseids, pathinfoarray[i]->clauseids))
1433  break;
1434  }
1435  if (i < npaths)
1436  {
1437  /* duplicate clauseids, keep the cheaper one */
1438  Cost ncost;
1439  Cost ocost;
1440  Selectivity nselec;
1441  Selectivity oselec;
1442 
1443  cost_bitmap_tree_node(pathinfo->path, &ncost, &nselec);
1444  cost_bitmap_tree_node(pathinfoarray[i]->path, &ocost, &oselec);
1445  if (ncost < ocost)
1446  pathinfoarray[i] = pathinfo;
1447  }
1448  else
1449  {
1450  /* not duplicate clauseids, add to array */
1451  pathinfoarray[npaths++] = pathinfo;
1452  }
1453  }
1454 
1455  /* If only one surviving path, we're done */
1456  if (npaths == 1)
1457  return pathinfoarray[0]->path;
1458 
1459  /* Sort the surviving paths by index access cost */
1460  qsort(pathinfoarray, npaths, sizeof(PathClauseUsage *),
1462 
1463  /*
1464  * For each surviving index, consider it as an "AND group leader", and see
1465  * whether adding on any of the later indexes results in an AND path with
1466  * cheaper total cost than before. Then take the cheapest AND group.
1467  *
1468  * Note: paths that are either clauseless or unclassifiable will have
1469  * empty clauseids, so that they will not be rejected by the clauseids
1470  * filter here, nor will they cause later paths to be rejected by it.
1471  */
1472  for (i = 0; i < npaths; i++)
1473  {
1474  Cost costsofar;
1475  List *qualsofar;
1476  Bitmapset *clauseidsofar;
1477 
1478  pathinfo = pathinfoarray[i];
1479  paths = list_make1(pathinfo->path);
1480  costsofar = bitmap_scan_cost_est(root, rel, pathinfo->path);
1481  qualsofar = list_concat_copy(pathinfo->quals, pathinfo->preds);
1482  clauseidsofar = bms_copy(pathinfo->clauseids);
1483 
1484  for (j = i + 1; j < npaths; j++)
1485  {
1486  Cost newcost;
1487 
1488  pathinfo = pathinfoarray[j];
1489  /* Check for redundancy */
1490  if (bms_overlap(pathinfo->clauseids, clauseidsofar))
1491  continue; /* consider it redundant */
1492  if (pathinfo->preds)
1493  {
1494  bool redundant = false;
1495 
1496  /* we check each predicate clause separately */
1497  foreach(l, pathinfo->preds)
1498  {
1499  Node *np = (Node *) lfirst(l);
1500 
1501  if (predicate_implied_by(list_make1(np), qualsofar, false))
1502  {
1503  redundant = true;
1504  break; /* out of inner foreach loop */
1505  }
1506  }
1507  if (redundant)
1508  continue;
1509  }
1510  /* tentatively add new path to paths, so we can estimate cost */
1511  paths = lappend(paths, pathinfo->path);
1512  newcost = bitmap_and_cost_est(root, rel, paths);
1513  if (newcost < costsofar)
1514  {
1515  /* keep new path in paths, update subsidiary variables */
1516  costsofar = newcost;
1517  qualsofar = list_concat(qualsofar, pathinfo->quals);
1518  qualsofar = list_concat(qualsofar, pathinfo->preds);
1519  clauseidsofar = bms_add_members(clauseidsofar,
1520  pathinfo->clauseids);
1521  }
1522  else
1523  {
1524  /* reject new path, remove it from paths list */
1525  paths = list_truncate(paths, list_length(paths) - 1);
1526  }
1527  }
1528 
1529  /* Keep the cheapest AND-group (or singleton) */
1530  if (i == 0 || costsofar < bestcost)
1531  {
1532  bestpaths = paths;
1533  bestcost = costsofar;
1534  }
1535 
1536  /* some easy cleanup (we don't try real hard though) */
1537  list_free(qualsofar);
1538  }
1539 
1540  if (list_length(bestpaths) == 1)
1541  return (Path *) linitial(bestpaths); /* no need for AND */
1542  return (Path *) create_bitmap_and_path(root, rel, bestpaths);
1543 }
1544 
1545 /* qsort comparator to sort in increasing index access cost order */
1546 static int
1547 path_usage_comparator(const void *a, const void *b)
1548 {
1549  PathClauseUsage *pa = *(PathClauseUsage *const *) a;
1550  PathClauseUsage *pb = *(PathClauseUsage *const *) b;
1551  Cost acost;
1552  Cost bcost;
1553  Selectivity aselec;
1554  Selectivity bselec;
1555 
1556  cost_bitmap_tree_node(pa->path, &acost, &aselec);
1557  cost_bitmap_tree_node(pb->path, &bcost, &bselec);
1558 
1559  /*
1560  * If costs are the same, sort by selectivity.
1561  */
1562  if (acost < bcost)
1563  return -1;
1564  if (acost > bcost)
1565  return 1;
1566 
1567  if (aselec < bselec)
1568  return -1;
1569  if (aselec > bselec)
1570  return 1;
1571 
1572  return 0;
1573 }
1574 
1575 /*
1576  * Estimate the cost of actually executing a bitmap scan with a single
1577  * index path (which could be a BitmapAnd or BitmapOr node).
1578  */
1579 static Cost
1581 {
1582  BitmapHeapPath bpath;
1583 
1584  /* Set up a dummy BitmapHeapPath */
1585  bpath.path.type = T_BitmapHeapPath;
1586  bpath.path.pathtype = T_BitmapHeapScan;
1587  bpath.path.parent = rel;
1588  bpath.path.pathtarget = rel->reltarget;
1589  bpath.path.param_info = ipath->param_info;
1590  bpath.path.pathkeys = NIL;
1591  bpath.bitmapqual = ipath;
1592 
1593  /*
1594  * Check the cost of temporary path without considering parallelism.
1595  * Parallel bitmap heap path will be considered at later stage.
1596  */
1597  bpath.path.parallel_workers = 0;
1598 
1599  /* Now we can do cost_bitmap_heap_scan */
1600  cost_bitmap_heap_scan(&bpath.path, root, rel,
1601  bpath.path.param_info,
1602  ipath,
1603  get_loop_count(root, rel->relid,
1604  PATH_REQ_OUTER(ipath)));
1605 
1606  return bpath.path.total_cost;
1607 }
1608 
1609 /*
1610  * Estimate the cost of actually executing a BitmapAnd scan with the given
1611  * inputs.
1612  */
1613 static Cost
1615 {
1616  BitmapAndPath *apath;
1617 
1618  /*
1619  * Might as well build a real BitmapAndPath here, as the work is slightly
1620  * too complicated to be worth repeating just to save one palloc.
1621  */
1622  apath = create_bitmap_and_path(root, rel, paths);
1623 
1624  return bitmap_scan_cost_est(root, rel, (Path *) apath);
1625 }
1626 
1627 
1628 /*
1629  * classify_index_clause_usage
1630  * Construct a PathClauseUsage struct describing the WHERE clauses and
1631  * index predicate clauses used by the given indexscan path.
1632  * We consider two clauses the same if they are equal().
1633  *
1634  * At some point we might want to migrate this info into the Path data
1635  * structure proper, but for the moment it's only needed within
1636  * choose_bitmap_and().
1637  *
1638  * *clauselist is used and expanded as needed to identify all the distinct
1639  * clauses seen across successive calls. Caller must initialize it to NIL
1640  * before first call of a set.
1641  */
1642 static PathClauseUsage *
1644 {
1645  PathClauseUsage *result;
1646  Bitmapset *clauseids;
1647  ListCell *lc;
1648 
1649  result = (PathClauseUsage *) palloc(sizeof(PathClauseUsage));
1650  result->path = path;
1651 
1652  /* Recursively find the quals and preds used by the path */
1653  result->quals = NIL;
1654  result->preds = NIL;
1655  find_indexpath_quals(path, &result->quals, &result->preds);
1656 
1657  /*
1658  * Some machine-generated queries have outlandish numbers of qual clauses.
1659  * To avoid getting into O(N^2) behavior even in this preliminary
1660  * classification step, we want to limit the number of entries we can
1661  * accumulate in *clauselist. Treat any path with more than 100 quals +
1662  * preds as unclassifiable, which will cause calling code to consider it
1663  * distinct from all other paths.
1664  */
1665  if (list_length(result->quals) + list_length(result->preds) > 100)
1666  {
1667  result->clauseids = NULL;
1668  result->unclassifiable = true;
1669  return result;
1670  }
1671 
1672  /* Build up a bitmapset representing the quals and preds */
1673  clauseids = NULL;
1674  foreach(lc, result->quals)
1675  {
1676  Node *node = (Node *) lfirst(lc);
1677 
1678  clauseids = bms_add_member(clauseids,
1679  find_list_position(node, clauselist));
1680  }
1681  foreach(lc, result->preds)
1682  {
1683  Node *node = (Node *) lfirst(lc);
1684 
1685  clauseids = bms_add_member(clauseids,
1686  find_list_position(node, clauselist));
1687  }
1688  result->clauseids = clauseids;
1689  result->unclassifiable = false;
1690 
1691  return result;
1692 }
1693 
1694 
1695 /*
1696  * find_indexpath_quals
1697  *
1698  * Given the Path structure for a plain or bitmap indexscan, extract lists
1699  * of all the index clauses and index predicate conditions used in the Path.
1700  * These are appended to the initial contents of *quals and *preds (hence
1701  * caller should initialize those to NIL).
1702  *
1703  * Note we are not trying to produce an accurate representation of the AND/OR
1704  * semantics of the Path, but just find out all the base conditions used.
1705  *
1706  * The result lists contain pointers to the expressions used in the Path,
1707  * but all the list cells are freshly built, so it's safe to destructively
1708  * modify the lists (eg, by concat'ing with other lists).
1709  */
1710 static void
1711 find_indexpath_quals(Path *bitmapqual, List **quals, List **preds)
1712 {
1713  if (IsA(bitmapqual, BitmapAndPath))
1714  {
1715  BitmapAndPath *apath = (BitmapAndPath *) bitmapqual;
1716  ListCell *l;
1717 
1718  foreach(l, apath->bitmapquals)
1719  {
1720  find_indexpath_quals((Path *) lfirst(l), quals, preds);
1721  }
1722  }
1723  else if (IsA(bitmapqual, BitmapOrPath))
1724  {
1725  BitmapOrPath *opath = (BitmapOrPath *) bitmapqual;
1726  ListCell *l;
1727 
1728  foreach(l, opath->bitmapquals)
1729  {
1730  find_indexpath_quals((Path *) lfirst(l), quals, preds);
1731  }
1732  }
1733  else if (IsA(bitmapqual, IndexPath))
1734  {
1735  IndexPath *ipath = (IndexPath *) bitmapqual;
1736  ListCell *l;
1737 
1738  foreach(l, ipath->indexclauses)
1739  {
1740  IndexClause *iclause = (IndexClause *) lfirst(l);
1741 
1742  *quals = lappend(*quals, iclause->rinfo->clause);
1743  }
1744  *preds = list_concat(*preds, ipath->indexinfo->indpred);
1745  }
1746  else
1747  elog(ERROR, "unrecognized node type: %d", nodeTag(bitmapqual));
1748 }
1749 
1750 
1751 /*
1752  * find_list_position
1753  * Return the given node's position (counting from 0) in the given
1754  * list of nodes. If it's not equal() to any existing list member,
1755  * add it at the end, and return that position.
1756  */
1757 static int
1758 find_list_position(Node *node, List **nodelist)
1759 {
1760  int i;
1761  ListCell *lc;
1762 
1763  i = 0;
1764  foreach(lc, *nodelist)
1765  {
1766  Node *oldnode = (Node *) lfirst(lc);
1767 
1768  if (equal(node, oldnode))
1769  return i;
1770  i++;
1771  }
1772 
1773  *nodelist = lappend(*nodelist, node);
1774 
1775  return i;
1776 }
1777 
1778 
1779 /*
1780  * check_index_only
1781  * Determine whether an index-only scan is possible for this index.
1782  */
1783 static bool
1785 {
1786  bool result;
1787  Bitmapset *attrs_used = NULL;
1788  Bitmapset *index_canreturn_attrs = NULL;
1789  ListCell *lc;
1790  int i;
1791 
1792  /* Index-only scans must be enabled */
1793  if (!enable_indexonlyscan)
1794  return false;
1795 
1796  /*
1797  * Check that all needed attributes of the relation are available from the
1798  * index.
1799  */
1800 
1801  /*
1802  * First, identify all the attributes needed for joins or final output.
1803  * Note: we must look at rel's targetlist, not the attr_needed data,
1804  * because attr_needed isn't computed for inheritance child rels.
1805  */
1806  pull_varattnos((Node *) rel->reltarget->exprs, rel->relid, &attrs_used);
1807 
1808  /*
1809  * Add all the attributes used by restriction clauses; but consider only
1810  * those clauses not implied by the index predicate, since ones that are
1811  * so implied don't need to be checked explicitly in the plan.
1812  *
1813  * Note: attributes used only in index quals would not be needed at
1814  * runtime either, if we are certain that the index is not lossy. However
1815  * it'd be complicated to account for that accurately, and it doesn't
1816  * matter in most cases, since we'd conclude that such attributes are
1817  * available from the index anyway.
1818  */
1819  foreach(lc, index->indrestrictinfo)
1820  {
1821  RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
1822 
1823  pull_varattnos((Node *) rinfo->clause, rel->relid, &attrs_used);
1824  }
1825 
1826  /*
1827  * Construct a bitmapset of columns that the index can return back in an
1828  * index-only scan.
1829  */
1830  for (i = 0; i < index->ncolumns; i++)
1831  {
1832  int attno = index->indexkeys[i];
1833 
1834  /*
1835  * For the moment, we just ignore index expressions. It might be nice
1836  * to do something with them, later.
1837  */
1838  if (attno == 0)
1839  continue;
1840 
1841  if (index->canreturn[i])
1842  index_canreturn_attrs =
1843  bms_add_member(index_canreturn_attrs,
1845  }
1846 
1847  /* Do we have all the necessary attributes? */
1848  result = bms_is_subset(attrs_used, index_canreturn_attrs);
1849 
1850  bms_free(attrs_used);
1851  bms_free(index_canreturn_attrs);
1852 
1853  return result;
1854 }
1855 
1856 /*
1857  * get_loop_count
1858  * Choose the loop count estimate to use for costing a parameterized path
1859  * with the given set of outer relids.
1860  *
1861  * Since we produce parameterized paths before we've begun to generate join
1862  * relations, it's impossible to predict exactly how many times a parameterized
1863  * path will be iterated; we don't know the size of the relation that will be
1864  * on the outside of the nestloop. However, we should try to account for
1865  * multiple iterations somehow in costing the path. The heuristic embodied
1866  * here is to use the rowcount of the smallest other base relation needed in
1867  * the join clauses used by the path. (We could alternatively consider the
1868  * largest one, but that seems too optimistic.) This is of course the right
1869  * answer for single-other-relation cases, and it seems like a reasonable
1870  * zero-order approximation for multiway-join cases.
1871  *
1872  * In addition, we check to see if the other side of each join clause is on
1873  * the inside of some semijoin that the current relation is on the outside of.
1874  * If so, the only way that a parameterized path could be used is if the
1875  * semijoin RHS has been unique-ified, so we should use the number of unique
1876  * RHS rows rather than using the relation's raw rowcount.
1877  *
1878  * Note: for this to work, allpaths.c must establish all baserel size
1879  * estimates before it begins to compute paths, or at least before it
1880  * calls create_index_paths().
1881  */
1882 static double
1883 get_loop_count(PlannerInfo *root, Index cur_relid, Relids outer_relids)
1884 {
1885  double result;
1886  int outer_relid;
1887 
1888  /* For a non-parameterized path, just return 1.0 quickly */
1889  if (outer_relids == NULL)
1890  return 1.0;
1891 
1892  result = 0.0;
1893  outer_relid = -1;
1894  while ((outer_relid = bms_next_member(outer_relids, outer_relid)) >= 0)
1895  {
1896  RelOptInfo *outer_rel;
1897  double rowcount;
1898 
1899  /* Paranoia: ignore bogus relid indexes */
1900  if (outer_relid >= root->simple_rel_array_size)
1901  continue;
1902  outer_rel = root->simple_rel_array[outer_relid];
1903  if (outer_rel == NULL)
1904  continue;
1905  Assert(outer_rel->relid == outer_relid); /* sanity check on array */
1906 
1907  /* Other relation could be proven empty, if so ignore */
1908  if (IS_DUMMY_REL(outer_rel))
1909  continue;
1910 
1911  /* Otherwise, rel's rows estimate should be valid by now */
1912  Assert(outer_rel->rows > 0);
1913 
1914  /* Check to see if rel is on the inside of any semijoins */
1915  rowcount = adjust_rowcount_for_semijoins(root,
1916  cur_relid,
1917  outer_relid,
1918  outer_rel->rows);
1919 
1920  /* Remember smallest row count estimate among the outer rels */
1921  if (result == 0.0 || result > rowcount)
1922  result = rowcount;
1923  }
1924  /* Return 1.0 if we found no valid relations (shouldn't happen) */
1925  return (result > 0.0) ? result : 1.0;
1926 }
1927 
1928 /*
1929  * Check to see if outer_relid is on the inside of any semijoin that cur_relid
1930  * is on the outside of. If so, replace rowcount with the estimated number of
1931  * unique rows from the semijoin RHS (assuming that's smaller, which it might
1932  * not be). The estimate is crude but it's the best we can do at this stage
1933  * of the proceedings.
1934  */
1935 static double
1937  Index cur_relid,
1938  Index outer_relid,
1939  double rowcount)
1940 {
1941  ListCell *lc;
1942 
1943  foreach(lc, root->join_info_list)
1944  {
1945  SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(lc);
1946 
1947  if (sjinfo->jointype == JOIN_SEMI &&
1948  bms_is_member(cur_relid, sjinfo->syn_lefthand) &&
1949  bms_is_member(outer_relid, sjinfo->syn_righthand))
1950  {
1951  /* Estimate number of unique-ified rows */
1952  double nraw;
1953  double nunique;
1954 
1955  nraw = approximate_joinrel_size(root, sjinfo->syn_righthand);
1956  nunique = estimate_num_groups(root,
1957  sjinfo->semi_rhs_exprs,
1958  nraw,
1959  NULL,
1960  NULL);
1961  if (rowcount > nunique)
1962  rowcount = nunique;
1963  }
1964  }
1965  return rowcount;
1966 }
1967 
1968 /*
1969  * Make an approximate estimate of the size of a joinrel.
1970  *
1971  * We don't have enough info at this point to get a good estimate, so we
1972  * just multiply the base relation sizes together. Fortunately, this is
1973  * the right answer anyway for the most common case with a single relation
1974  * on the RHS of a semijoin. Also, estimate_num_groups() has only a weak
1975  * dependency on its input_rows argument (it basically uses it as a clamp).
1976  * So we might be able to get a fairly decent end result even with a severe
1977  * overestimate of the RHS's raw size.
1978  */
1979 static double
1981 {
1982  double rowcount = 1.0;
1983  int relid;
1984 
1985  relid = -1;
1986  while ((relid = bms_next_member(relids, relid)) >= 0)
1987  {
1988  RelOptInfo *rel;
1989 
1990  /* Paranoia: ignore bogus relid indexes */
1991  if (relid >= root->simple_rel_array_size)
1992  continue;
1993  rel = root->simple_rel_array[relid];
1994  if (rel == NULL)
1995  continue;
1996  Assert(rel->relid == relid); /* sanity check on array */
1997 
1998  /* Relation could be proven empty, if so ignore */
1999  if (IS_DUMMY_REL(rel))
2000  continue;
2001 
2002  /* Otherwise, rel's rows estimate should be valid by now */
2003  Assert(rel->rows > 0);
2004 
2005  /* Accumulate product */
2006  rowcount *= rel->rows;
2007  }
2008  return rowcount;
2009 }
2010 
2011 
2012 /****************************************************************************
2013  * ---- ROUTINES TO CHECK QUERY CLAUSES ----
2014  ****************************************************************************/
2015 
2016 /*
2017  * match_restriction_clauses_to_index
2018  * Identify restriction clauses for the rel that match the index.
2019  * Matching clauses are added to *clauseset.
2020  */
2021 static void
2024  IndexClauseSet *clauseset)
2025 {
2026  /* We can ignore clauses that are implied by the index predicate */
2027  match_clauses_to_index(root, index->indrestrictinfo, index, clauseset);
2028 }
2029 
2030 /*
2031  * match_join_clauses_to_index
2032  * Identify join clauses for the rel that match the index.
2033  * Matching clauses are added to *clauseset.
2034  * Also, add any potentially usable join OR clauses to *joinorclauses.
2035  */
2036 static void
2038  RelOptInfo *rel, IndexOptInfo *index,
2039  IndexClauseSet *clauseset,
2040  List **joinorclauses)
2041 {
2042  ListCell *lc;
2043 
2044  /* Scan the rel's join clauses */
2045  foreach(lc, rel->joininfo)
2046  {
2047  RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
2048 
2049  /* Check if clause can be moved to this rel */
2050  if (!join_clause_is_movable_to(rinfo, rel))
2051  continue;
2052 
2053  /* Potentially usable, so see if it matches the index or is an OR */
2054  if (restriction_is_or_clause(rinfo))
2055  *joinorclauses = lappend(*joinorclauses, rinfo);
2056  else
2057  match_clause_to_index(root, rinfo, index, clauseset);
2058  }
2059 }
2060 
2061 /*
2062  * match_eclass_clauses_to_index
2063  * Identify EquivalenceClass join clauses for the rel that match the index.
2064  * Matching clauses are added to *clauseset.
2065  */
2066 static void
2068  IndexClauseSet *clauseset)
2069 {
2070  int indexcol;
2071 
2072  /* No work if rel is not in any such ECs */
2073  if (!index->rel->has_eclass_joins)
2074  return;
2075 
2076  for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
2077  {
2079  List *clauses;
2080 
2081  /* Generate clauses, skipping any that join to lateral_referencers */
2082  arg.index = index;
2083  arg.indexcol = indexcol;
2085  index->rel,
2087  (void *) &arg,
2088  index->rel->lateral_referencers);
2089 
2090  /*
2091  * We have to check whether the results actually do match the index,
2092  * since for non-btree indexes the EC's equality operators might not
2093  * be in the index opclass (cf ec_member_matches_indexcol).
2094  */
2095  match_clauses_to_index(root, clauses, index, clauseset);
2096  }
2097 }
2098 
2099 /*
2100  * match_clauses_to_index
2101  * Perform match_clause_to_index() for each clause in a list.
2102  * Matching clauses are added to *clauseset.
2103  */
2104 static void
2106  List *clauses,
2108  IndexClauseSet *clauseset)
2109 {
2110  ListCell *lc;
2111 
2112  foreach(lc, clauses)
2113  {
2114  RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
2115 
2116  match_clause_to_index(root, rinfo, index, clauseset);
2117  }
2118 }
2119 
2120 /*
2121  * match_clause_to_index
2122  * Test whether a qual clause can be used with an index.
2123  *
2124  * If the clause is usable, add an IndexClause entry for it to the appropriate
2125  * list in *clauseset. (*clauseset must be initialized to zeroes before first
2126  * call.)
2127  *
2128  * Note: in some circumstances we may find the same RestrictInfos coming from
2129  * multiple places. Defend against redundant outputs by refusing to add a
2130  * clause twice (pointer equality should be a good enough check for this).
2131  *
2132  * Note: it's possible that a badly-defined index could have multiple matching
2133  * columns. We always select the first match if so; this avoids scenarios
2134  * wherein we get an inflated idea of the index's selectivity by using the
2135  * same clause multiple times with different index columns.
2136  */
2137 static void
2139  RestrictInfo *rinfo,
2141  IndexClauseSet *clauseset)
2142 {
2143  int indexcol;
2144 
2145  /*
2146  * Never match pseudoconstants to indexes. (Normally a match could not
2147  * happen anyway, since a pseudoconstant clause couldn't contain a Var,
2148  * but what if someone builds an expression index on a constant? It's not
2149  * totally unreasonable to do so with a partial index, either.)
2150  */
2151  if (rinfo->pseudoconstant)
2152  return;
2153 
2154  /*
2155  * If clause can't be used as an indexqual because it must wait till after
2156  * some lower-security-level restriction clause, reject it.
2157  */
2158  if (!restriction_is_securely_promotable(rinfo, index->rel))
2159  return;
2160 
2161  /* OK, check each index key column for a match */
2162  for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
2163  {
2164  IndexClause *iclause;
2165  ListCell *lc;
2166 
2167  /* Ignore duplicates */
2168  foreach(lc, clauseset->indexclauses[indexcol])
2169  {
2170  iclause = (IndexClause *) lfirst(lc);
2171 
2172  if (iclause->rinfo == rinfo)
2173  return;
2174  }
2175 
2176  /* OK, try to match the clause to the index column */
2177  iclause = match_clause_to_indexcol(root,
2178  rinfo,
2179  indexcol,
2180  index);
2181  if (iclause)
2182  {
2183  /* Success, so record it */
2184  clauseset->indexclauses[indexcol] =
2185  lappend(clauseset->indexclauses[indexcol], iclause);
2186  clauseset->nonempty = true;
2187  return;
2188  }
2189  }
2190 }
2191 
2192 /*
2193  * match_clause_to_indexcol()
2194  * Determine whether a restriction clause matches a column of an index,
2195  * and if so, build an IndexClause node describing the details.
2196  *
2197  * To match an index normally, an operator clause:
2198  *
2199  * (1) must be in the form (indexkey op const) or (const op indexkey);
2200  * and
2201  * (2) must contain an operator which is in the index's operator family
2202  * for this column; and
2203  * (3) must match the collation of the index, if collation is relevant.
2204  *
2205  * Our definition of "const" is exceedingly liberal: we allow anything that
2206  * doesn't involve a volatile function or a Var of the index's relation.
2207  * In particular, Vars belonging to other relations of the query are
2208  * accepted here, since a clause of that form can be used in a
2209  * parameterized indexscan. It's the responsibility of higher code levels
2210  * to manage restriction and join clauses appropriately.
2211  *
2212  * Note: we do need to check for Vars of the index's relation on the
2213  * "const" side of the clause, since clauses like (a.f1 OP (b.f2 OP a.f3))
2214  * are not processable by a parameterized indexscan on a.f1, whereas
2215  * something like (a.f1 OP (b.f2 OP c.f3)) is.
2216  *
2217  * Presently, the executor can only deal with indexquals that have the
2218  * indexkey on the left, so we can only use clauses that have the indexkey
2219  * on the right if we can commute the clause to put the key on the left.
2220  * We handle that by generating an IndexClause with the correctly-commuted
2221  * opclause as a derived indexqual.
2222  *
2223  * If the index has a collation, the clause must have the same collation.
2224  * For collation-less indexes, we assume it doesn't matter; this is
2225  * necessary for cases like "hstore ? text", wherein hstore's operators
2226  * don't care about collation but the clause will get marked with a
2227  * collation anyway because of the text argument. (This logic is
2228  * embodied in the macro IndexCollMatchesExprColl.)
2229  *
2230  * It is also possible to match RowCompareExpr clauses to indexes (but
2231  * currently, only btree indexes handle this).
2232  *
2233  * It is also possible to match ScalarArrayOpExpr clauses to indexes, when
2234  * the clause is of the form "indexkey op ANY (arrayconst)".
2235  *
2236  * For boolean indexes, it is also possible to match the clause directly
2237  * to the indexkey; or perhaps the clause is (NOT indexkey).
2238  *
2239  * And, last but not least, some operators and functions can be processed
2240  * to derive (typically lossy) indexquals from a clause that isn't in
2241  * itself indexable. If we see that any operand of an OpExpr or FuncExpr
2242  * matches the index key, and the function has a planner support function
2243  * attached to it, we'll invoke the support function to see if such an
2244  * indexqual can be built.
2245  *
2246  * 'rinfo' is the clause to be tested (as a RestrictInfo node).
2247  * 'indexcol' is a column number of 'index' (counting from 0).
2248  * 'index' is the index of interest.
2249  *
2250  * Returns an IndexClause if the clause can be used with this index key,
2251  * or NULL if not.
2252  *
2253  * NOTE: returns NULL if clause is an OR or AND clause; it is the
2254  * responsibility of higher-level routines to cope with those.
2255  */
2256 static IndexClause *
2258  RestrictInfo *rinfo,
2259  int indexcol,
2261 {
2262  IndexClause *iclause;
2263  Expr *clause = rinfo->clause;
2264  Oid opfamily;
2265 
2266  Assert(indexcol < index->nkeycolumns);
2267 
2268  /*
2269  * Historically this code has coped with NULL clauses. That's probably
2270  * not possible anymore, but we might as well continue to cope.
2271  */
2272  if (clause == NULL)
2273  return NULL;
2274 
2275  /* First check for boolean-index cases. */
2276  opfamily = index->opfamily[indexcol];
2277  if (IsBooleanOpfamily(opfamily))
2278  {
2279  iclause = match_boolean_index_clause(root, rinfo, indexcol, index);
2280  if (iclause)
2281  return iclause;
2282  }
2283 
2284  /*
2285  * Clause must be an opclause, funcclause, ScalarArrayOpExpr, or
2286  * RowCompareExpr. Or, if the index supports it, we can handle IS
2287  * NULL/NOT NULL clauses.
2288  */
2289  if (IsA(clause, OpExpr))
2290  {
2291  return match_opclause_to_indexcol(root, rinfo, indexcol, index);
2292  }
2293  else if (IsA(clause, FuncExpr))
2294  {
2295  return match_funcclause_to_indexcol(root, rinfo, indexcol, index);
2296  }
2297  else if (IsA(clause, ScalarArrayOpExpr))
2298  {
2299  return match_saopclause_to_indexcol(root, rinfo, indexcol, index);
2300  }
2301  else if (IsA(clause, RowCompareExpr))
2302  {
2303  return match_rowcompare_to_indexcol(root, rinfo, indexcol, index);
2304  }
2305  else if (index->amsearchnulls && IsA(clause, NullTest))
2306  {
2307  NullTest *nt = (NullTest *) clause;
2308 
2309  if (!nt->argisrow &&
2310  match_index_to_operand((Node *) nt->arg, indexcol, index))
2311  {
2312  iclause = makeNode(IndexClause);
2313  iclause->rinfo = rinfo;
2314  iclause->indexquals = list_make1(rinfo);
2315  iclause->lossy = false;
2316  iclause->indexcol = indexcol;
2317  iclause->indexcols = NIL;
2318  return iclause;
2319  }
2320  }
2321 
2322  return NULL;
2323 }
2324 
2325 /*
2326  * IsBooleanOpfamily
2327  * Detect whether an opfamily supports boolean equality as an operator.
2328  *
2329  * If the opfamily OID is in the range of built-in objects, we can rely
2330  * on hard-wired knowledge of which built-in opfamilies support this.
2331  * For extension opfamilies, there's no choice but to do a catcache lookup.
2332  */
2333 static bool
2335 {
2336  if (opfamily < FirstNormalObjectId)
2337  return IsBuiltinBooleanOpfamily(opfamily);
2338  else
2339  return op_in_opfamily(BooleanEqualOperator, opfamily);
2340 }
2341 
2342 /*
2343  * match_boolean_index_clause
2344  * Recognize restriction clauses that can be matched to a boolean index.
2345  *
2346  * The idea here is that, for an index on a boolean column that supports the
2347  * BooleanEqualOperator, we can transform a plain reference to the indexkey
2348  * into "indexkey = true", or "NOT indexkey" into "indexkey = false", etc,
2349  * so as to make the expression indexable using the index's "=" operator.
2350  * Since Postgres 8.1, we must do this because constant simplification does
2351  * the reverse transformation; without this code there'd be no way to use
2352  * such an index at all.
2353  *
2354  * This should be called only when IsBooleanOpfamily() recognizes the
2355  * index's operator family. We check to see if the clause matches the
2356  * index's key, and if so, build a suitable IndexClause.
2357  */
2358 static IndexClause *
2360  RestrictInfo *rinfo,
2361  int indexcol,
2363 {
2364  Node *clause = (Node *) rinfo->clause;
2365  Expr *op = NULL;
2366 
2367  /* Direct match? */
2368  if (match_index_to_operand(clause, indexcol, index))
2369  {
2370  /* convert to indexkey = TRUE */
2371  op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2372  (Expr *) clause,
2373  (Expr *) makeBoolConst(true, false),
2375  }
2376  /* NOT clause? */
2377  else if (is_notclause(clause))
2378  {
2379  Node *arg = (Node *) get_notclausearg((Expr *) clause);
2380 
2381  if (match_index_to_operand(arg, indexcol, index))
2382  {
2383  /* convert to indexkey = FALSE */
2384  op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2385  (Expr *) arg,
2386  (Expr *) makeBoolConst(false, false),
2388  }
2389  }
2390 
2391  /*
2392  * Since we only consider clauses at top level of WHERE, we can convert
2393  * indexkey IS TRUE and indexkey IS FALSE to index searches as well. The
2394  * different meaning for NULL isn't important.
2395  */
2396  else if (clause && IsA(clause, BooleanTest))
2397  {
2398  BooleanTest *btest = (BooleanTest *) clause;
2399  Node *arg = (Node *) btest->arg;
2400 
2401  if (btest->booltesttype == IS_TRUE &&
2402  match_index_to_operand(arg, indexcol, index))
2403  {
2404  /* convert to indexkey = TRUE */
2405  op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2406  (Expr *) arg,
2407  (Expr *) makeBoolConst(true, false),
2409  }
2410  else if (btest->booltesttype == IS_FALSE &&
2411  match_index_to_operand(arg, indexcol, index))
2412  {
2413  /* convert to indexkey = FALSE */
2414  op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2415  (Expr *) arg,
2416  (Expr *) makeBoolConst(false, false),
2418  }
2419  }
2420 
2421  /*
2422  * If we successfully made an operator clause from the given qual, we must
2423  * wrap it in an IndexClause. It's not lossy.
2424  */
2425  if (op)
2426  {
2427  IndexClause *iclause = makeNode(IndexClause);
2428 
2429  iclause->rinfo = rinfo;
2430  iclause->indexquals = list_make1(make_simple_restrictinfo(root, op));
2431  iclause->lossy = false;
2432  iclause->indexcol = indexcol;
2433  iclause->indexcols = NIL;
2434  return iclause;
2435  }
2436 
2437  return NULL;
2438 }
2439 
2440 /*
2441  * match_opclause_to_indexcol()
2442  * Handles the OpExpr case for match_clause_to_indexcol(),
2443  * which see for comments.
2444  */
2445 static IndexClause *
2447  RestrictInfo *rinfo,
2448  int indexcol,
2450 {
2451  IndexClause *iclause;
2452  OpExpr *clause = (OpExpr *) rinfo->clause;
2453  Node *leftop,
2454  *rightop;
2455  Oid expr_op;
2456  Oid expr_coll;
2457  Index index_relid;
2458  Oid opfamily;
2459  Oid idxcollation;
2460 
2461  /*
2462  * Only binary operators need apply. (In theory, a planner support
2463  * function could do something with a unary operator, but it seems
2464  * unlikely to be worth the cycles to check.)
2465  */
2466  if (list_length(clause->args) != 2)
2467  return NULL;
2468 
2469  leftop = (Node *) linitial(clause->args);
2470  rightop = (Node *) lsecond(clause->args);
2471  expr_op = clause->opno;
2472  expr_coll = clause->inputcollid;
2473 
2474  index_relid = index->rel->relid;
2475  opfamily = index->opfamily[indexcol];
2476  idxcollation = index->indexcollations[indexcol];
2477 
2478  /*
2479  * Check for clauses of the form: (indexkey operator constant) or
2480  * (constant operator indexkey). See match_clause_to_indexcol's notes
2481  * about const-ness.
2482  *
2483  * Note that we don't ask the support function about clauses that don't
2484  * have one of these forms. Again, in principle it might be possible to
2485  * do something, but it seems unlikely to be worth the cycles to check.
2486  */
2487  if (match_index_to_operand(leftop, indexcol, index) &&
2488  !bms_is_member(index_relid, rinfo->right_relids) &&
2489  !contain_volatile_functions(rightop))
2490  {
2491  if (IndexCollMatchesExprColl(idxcollation, expr_coll) &&
2492  op_in_opfamily(expr_op, opfamily))
2493  {
2494  iclause = makeNode(IndexClause);
2495  iclause->rinfo = rinfo;
2496  iclause->indexquals = list_make1(rinfo);
2497  iclause->lossy = false;
2498  iclause->indexcol = indexcol;
2499  iclause->indexcols = NIL;
2500  return iclause;
2501  }
2502 
2503  /*
2504  * If we didn't find a member of the index's opfamily, try the support
2505  * function for the operator's underlying function.
2506  */
2507  set_opfuncid(clause); /* make sure we have opfuncid */
2508  return get_index_clause_from_support(root,
2509  rinfo,
2510  clause->opfuncid,
2511  0, /* indexarg on left */
2512  indexcol,
2513  index);
2514  }
2515 
2516  if (match_index_to_operand(rightop, indexcol, index) &&
2517  !bms_is_member(index_relid, rinfo->left_relids) &&
2518  !contain_volatile_functions(leftop))
2519  {
2520  if (IndexCollMatchesExprColl(idxcollation, expr_coll))
2521  {
2522  Oid comm_op = get_commutator(expr_op);
2523 
2524  if (OidIsValid(comm_op) &&
2525  op_in_opfamily(comm_op, opfamily))
2526  {
2527  RestrictInfo *commrinfo;
2528 
2529  /* Build a commuted OpExpr and RestrictInfo */
2530  commrinfo = commute_restrictinfo(rinfo, comm_op);
2531 
2532  /* Make an IndexClause showing that as a derived qual */
2533  iclause = makeNode(IndexClause);
2534  iclause->rinfo = rinfo;
2535  iclause->indexquals = list_make1(commrinfo);
2536  iclause->lossy = false;
2537  iclause->indexcol = indexcol;
2538  iclause->indexcols = NIL;
2539  return iclause;
2540  }
2541  }
2542 
2543  /*
2544  * If we didn't find a member of the index's opfamily, try the support
2545  * function for the operator's underlying function.
2546  */
2547  set_opfuncid(clause); /* make sure we have opfuncid */
2548  return get_index_clause_from_support(root,
2549  rinfo,
2550  clause->opfuncid,
2551  1, /* indexarg on right */
2552  indexcol,
2553  index);
2554  }
2555 
2556  return NULL;
2557 }
2558 
2559 /*
2560  * match_funcclause_to_indexcol()
2561  * Handles the FuncExpr case for match_clause_to_indexcol(),
2562  * which see for comments.
2563  */
2564 static IndexClause *
2566  RestrictInfo *rinfo,
2567  int indexcol,
2569 {
2570  FuncExpr *clause = (FuncExpr *) rinfo->clause;
2571  int indexarg;
2572  ListCell *lc;
2573 
2574  /*
2575  * We have no built-in intelligence about function clauses, but if there's
2576  * a planner support function, it might be able to do something. But, to
2577  * cut down on wasted planning cycles, only call the support function if
2578  * at least one argument matches the target index column.
2579  *
2580  * Note that we don't insist on the other arguments being pseudoconstants;
2581  * the support function has to check that. This is to allow cases where
2582  * only some of the other arguments need to be included in the indexqual.
2583  */
2584  indexarg = 0;
2585  foreach(lc, clause->args)
2586  {
2587  Node *op = (Node *) lfirst(lc);
2588 
2589  if (match_index_to_operand(op, indexcol, index))
2590  {
2591  return get_index_clause_from_support(root,
2592  rinfo,
2593  clause->funcid,
2594  indexarg,
2595  indexcol,
2596  index);
2597  }
2598 
2599  indexarg++;
2600  }
2601 
2602  return NULL;
2603 }
2604 
2605 /*
2606  * get_index_clause_from_support()
2607  * If the function has a planner support function, try to construct
2608  * an IndexClause using indexquals created by the support function.
2609  */
2610 static IndexClause *
2612  RestrictInfo *rinfo,
2613  Oid funcid,
2614  int indexarg,
2615  int indexcol,
2617 {
2618  Oid prosupport = get_func_support(funcid);
2620  List *sresult;
2621 
2622  if (!OidIsValid(prosupport))
2623  return NULL;
2624 
2625  req.type = T_SupportRequestIndexCondition;
2626  req.root = root;
2627  req.funcid = funcid;
2628  req.node = (Node *) rinfo->clause;
2629  req.indexarg = indexarg;
2630  req.index = index;
2631  req.indexcol = indexcol;
2632  req.opfamily = index->opfamily[indexcol];
2633  req.indexcollation = index->indexcollations[indexcol];
2634 
2635  req.lossy = true; /* default assumption */
2636 
2637  sresult = (List *)
2638  DatumGetPointer(OidFunctionCall1(prosupport,
2639  PointerGetDatum(&req)));
2640 
2641  if (sresult != NIL)
2642  {
2643  IndexClause *iclause = makeNode(IndexClause);
2644  List *indexquals = NIL;
2645  ListCell *lc;
2646 
2647  /*
2648  * The support function API says it should just give back bare
2649  * clauses, so here we must wrap each one in a RestrictInfo.
2650  */
2651  foreach(lc, sresult)
2652  {
2653  Expr *clause = (Expr *) lfirst(lc);
2654 
2655  indexquals = lappend(indexquals,
2656  make_simple_restrictinfo(root, clause));
2657  }
2658 
2659  iclause->rinfo = rinfo;
2660  iclause->indexquals = indexquals;
2661  iclause->lossy = req.lossy;
2662  iclause->indexcol = indexcol;
2663  iclause->indexcols = NIL;
2664 
2665  return iclause;
2666  }
2667 
2668  return NULL;
2669 }
2670 
2671 /*
2672  * match_saopclause_to_indexcol()
2673  * Handles the ScalarArrayOpExpr case for match_clause_to_indexcol(),
2674  * which see for comments.
2675  */
2676 static IndexClause *
2678  RestrictInfo *rinfo,
2679  int indexcol,
2681 {
2682  ScalarArrayOpExpr *saop = (ScalarArrayOpExpr *) rinfo->clause;
2683  Node *leftop,
2684  *rightop;
2685  Relids right_relids;
2686  Oid expr_op;
2687  Oid expr_coll;
2688  Index index_relid;
2689  Oid opfamily;
2690  Oid idxcollation;
2691 
2692  /* We only accept ANY clauses, not ALL */
2693  if (!saop->useOr)
2694  return NULL;
2695  leftop = (Node *) linitial(saop->args);
2696  rightop = (Node *) lsecond(saop->args);
2697  right_relids = pull_varnos(root, rightop);
2698  expr_op = saop->opno;
2699  expr_coll = saop->inputcollid;
2700 
2701  index_relid = index->rel->relid;
2702  opfamily = index->opfamily[indexcol];
2703  idxcollation = index->indexcollations[indexcol];
2704 
2705  /*
2706  * We must have indexkey on the left and a pseudo-constant array argument.
2707  */
2708  if (match_index_to_operand(leftop, indexcol, index) &&
2709  !bms_is_member(index_relid, right_relids) &&
2710  !contain_volatile_functions(rightop))
2711  {
2712  if (IndexCollMatchesExprColl(idxcollation, expr_coll) &&
2713  op_in_opfamily(expr_op, opfamily))
2714  {
2715  IndexClause *iclause = makeNode(IndexClause);
2716 
2717  iclause->rinfo = rinfo;
2718  iclause->indexquals = list_make1(rinfo);
2719  iclause->lossy = false;
2720  iclause->indexcol = indexcol;
2721  iclause->indexcols = NIL;
2722  return iclause;
2723  }
2724 
2725  /*
2726  * We do not currently ask support functions about ScalarArrayOpExprs,
2727  * though in principle we could.
2728  */
2729  }
2730 
2731  return NULL;
2732 }
2733 
2734 /*
2735  * match_rowcompare_to_indexcol()
2736  * Handles the RowCompareExpr case for match_clause_to_indexcol(),
2737  * which see for comments.
2738  *
2739  * In this routine we check whether the first column of the row comparison
2740  * matches the target index column. This is sufficient to guarantee that some
2741  * index condition can be constructed from the RowCompareExpr --- the rest
2742  * is handled by expand_indexqual_rowcompare().
2743  */
2744 static IndexClause *
2746  RestrictInfo *rinfo,
2747  int indexcol,
2749 {
2750  RowCompareExpr *clause = (RowCompareExpr *) rinfo->clause;
2751  Index index_relid;
2752  Oid opfamily;
2753  Oid idxcollation;
2754  Node *leftop,
2755  *rightop;
2756  bool var_on_left;
2757  Oid expr_op;
2758  Oid expr_coll;
2759 
2760  /* Forget it if we're not dealing with a btree index */
2761  if (index->relam != BTREE_AM_OID)
2762  return NULL;
2763 
2764  index_relid = index->rel->relid;
2765  opfamily = index->opfamily[indexcol];
2766  idxcollation = index->indexcollations[indexcol];
2767 
2768  /*
2769  * We could do the matching on the basis of insisting that the opfamily
2770  * shown in the RowCompareExpr be the same as the index column's opfamily,
2771  * but that could fail in the presence of reverse-sort opfamilies: it'd be
2772  * a matter of chance whether RowCompareExpr had picked the forward or
2773  * reverse-sort family. So look only at the operator, and match if it is
2774  * a member of the index's opfamily (after commutation, if the indexkey is
2775  * on the right). We'll worry later about whether any additional
2776  * operators are matchable to the index.
2777  */
2778  leftop = (Node *) linitial(clause->largs);
2779  rightop = (Node *) linitial(clause->rargs);
2780  expr_op = linitial_oid(clause->opnos);
2781  expr_coll = linitial_oid(clause->inputcollids);
2782 
2783  /* Collations must match, if relevant */
2784  if (!IndexCollMatchesExprColl(idxcollation, expr_coll))
2785  return NULL;
2786 
2787  /*
2788  * These syntactic tests are the same as in match_opclause_to_indexcol()
2789  */
2790  if (match_index_to_operand(leftop, indexcol, index) &&
2791  !bms_is_member(index_relid, pull_varnos(root, rightop)) &&
2792  !contain_volatile_functions(rightop))
2793  {
2794  /* OK, indexkey is on left */
2795  var_on_left = true;
2796  }
2797  else if (match_index_to_operand(rightop, indexcol, index) &&
2798  !bms_is_member(index_relid, pull_varnos(root, leftop)) &&
2799  !contain_volatile_functions(leftop))
2800  {
2801  /* indexkey is on right, so commute the operator */
2802  expr_op = get_commutator(expr_op);
2803  if (expr_op == InvalidOid)
2804  return NULL;
2805  var_on_left = false;
2806  }
2807  else
2808  return NULL;
2809 
2810  /* We're good if the operator is the right type of opfamily member */
2811  switch (get_op_opfamily_strategy(expr_op, opfamily))
2812  {
2813  case BTLessStrategyNumber:
2817  return expand_indexqual_rowcompare(root,
2818  rinfo,
2819  indexcol,
2820  index,
2821  expr_op,
2822  var_on_left);
2823  }
2824 
2825  return NULL;
2826 }
2827 
2828 /*
2829  * expand_indexqual_rowcompare --- expand a single indexqual condition
2830  * that is a RowCompareExpr
2831  *
2832  * It's already known that the first column of the row comparison matches
2833  * the specified column of the index. We can use additional columns of the
2834  * row comparison as index qualifications, so long as they match the index
2835  * in the "same direction", ie, the indexkeys are all on the same side of the
2836  * clause and the operators are all the same-type members of the opfamilies.
2837  *
2838  * If all the columns of the RowCompareExpr match in this way, we just use it
2839  * as-is, except for possibly commuting it to put the indexkeys on the left.
2840  *
2841  * Otherwise, we build a shortened RowCompareExpr (if more than one
2842  * column matches) or a simple OpExpr (if the first-column match is all
2843  * there is). In these cases the modified clause is always "<=" or ">="
2844  * even when the original was "<" or ">" --- this is necessary to match all
2845  * the rows that could match the original. (We are building a lossy version
2846  * of the row comparison when we do this, so we set lossy = true.)
2847  *
2848  * Note: this is really just the last half of match_rowcompare_to_indexcol,
2849  * but we split it out for comprehensibility.
2850  */
2851 static IndexClause *
2853  RestrictInfo *rinfo,
2854  int indexcol,
2856  Oid expr_op,
2857  bool var_on_left)
2858 {
2859  IndexClause *iclause = makeNode(IndexClause);
2860  RowCompareExpr *clause = (RowCompareExpr *) rinfo->clause;
2861  int op_strategy;
2862  Oid op_lefttype;
2863  Oid op_righttype;
2864  int matching_cols;
2865  List *expr_ops;
2866  List *opfamilies;
2867  List *lefttypes;
2868  List *righttypes;
2869  List *new_ops;
2870  List *var_args;
2871  List *non_var_args;
2872 
2873  iclause->rinfo = rinfo;
2874  iclause->indexcol = indexcol;
2875 
2876  if (var_on_left)
2877  {
2878  var_args = clause->largs;
2879  non_var_args = clause->rargs;
2880  }
2881  else
2882  {
2883  var_args = clause->rargs;
2884  non_var_args = clause->largs;
2885  }
2886 
2887  get_op_opfamily_properties(expr_op, index->opfamily[indexcol], false,
2888  &op_strategy,
2889  &op_lefttype,
2890  &op_righttype);
2891 
2892  /* Initialize returned list of which index columns are used */
2893  iclause->indexcols = list_make1_int(indexcol);
2894 
2895  /* Build lists of ops, opfamilies and operator datatypes in case needed */
2896  expr_ops = list_make1_oid(expr_op);
2897  opfamilies = list_make1_oid(index->opfamily[indexcol]);
2898  lefttypes = list_make1_oid(op_lefttype);
2899  righttypes = list_make1_oid(op_righttype);
2900 
2901  /*
2902  * See how many of the remaining columns match some index column in the
2903  * same way. As in match_clause_to_indexcol(), the "other" side of any
2904  * potential index condition is OK as long as it doesn't use Vars from the
2905  * indexed relation.
2906  */
2907  matching_cols = 1;
2908 
2909  while (matching_cols < list_length(var_args))
2910  {
2911  Node *varop = (Node *) list_nth(var_args, matching_cols);
2912  Node *constop = (Node *) list_nth(non_var_args, matching_cols);
2913  int i;
2914 
2915  expr_op = list_nth_oid(clause->opnos, matching_cols);
2916  if (!var_on_left)
2917  {
2918  /* indexkey is on right, so commute the operator */
2919  expr_op = get_commutator(expr_op);
2920  if (expr_op == InvalidOid)
2921  break; /* operator is not usable */
2922  }
2923  if (bms_is_member(index->rel->relid, pull_varnos(root, constop)))
2924  break; /* no good, Var on wrong side */
2925  if (contain_volatile_functions(constop))
2926  break; /* no good, volatile comparison value */
2927 
2928  /*
2929  * The Var side can match any key column of the index.
2930  */
2931  for (i = 0; i < index->nkeycolumns; i++)
2932  {
2933  if (match_index_to_operand(varop, i, index) &&
2934  get_op_opfamily_strategy(expr_op,
2935  index->opfamily[i]) == op_strategy &&
2936  IndexCollMatchesExprColl(index->indexcollations[i],
2937  list_nth_oid(clause->inputcollids,
2938  matching_cols)))
2939  break;
2940  }
2941  if (i >= index->nkeycolumns)
2942  break; /* no match found */
2943 
2944  /* Add column number to returned list */
2945  iclause->indexcols = lappend_int(iclause->indexcols, i);
2946 
2947  /* Add operator info to lists */
2948  get_op_opfamily_properties(expr_op, index->opfamily[i], false,
2949  &op_strategy,
2950  &op_lefttype,
2951  &op_righttype);
2952  expr_ops = lappend_oid(expr_ops, expr_op);
2953  opfamilies = lappend_oid(opfamilies, index->opfamily[i]);
2954  lefttypes = lappend_oid(lefttypes, op_lefttype);
2955  righttypes = lappend_oid(righttypes, op_righttype);
2956 
2957  /* This column matches, keep scanning */
2958  matching_cols++;
2959  }
2960 
2961  /* Result is non-lossy if all columns are usable as index quals */
2962  iclause->lossy = (matching_cols != list_length(clause->opnos));
2963 
2964  /*
2965  * We can use rinfo->clause as-is if we have var on left and it's all
2966  * usable as index quals.
2967  */
2968  if (var_on_left && !iclause->lossy)
2969  iclause->indexquals = list_make1(rinfo);
2970  else
2971  {
2972  /*
2973  * We have to generate a modified rowcompare (possibly just one
2974  * OpExpr). The painful part of this is changing < to <= or > to >=,
2975  * so deal with that first.
2976  */
2977  if (!iclause->lossy)
2978  {
2979  /* very easy, just use the commuted operators */
2980  new_ops = expr_ops;
2981  }
2982  else if (op_strategy == BTLessEqualStrategyNumber ||
2983  op_strategy == BTGreaterEqualStrategyNumber)
2984  {
2985  /* easy, just use the same (possibly commuted) operators */
2986  new_ops = list_truncate(expr_ops, matching_cols);
2987  }
2988  else
2989  {
2990  ListCell *opfamilies_cell;
2991  ListCell *lefttypes_cell;
2992  ListCell *righttypes_cell;
2993 
2994  if (op_strategy == BTLessStrategyNumber)
2995  op_strategy = BTLessEqualStrategyNumber;
2996  else if (op_strategy == BTGreaterStrategyNumber)
2997  op_strategy = BTGreaterEqualStrategyNumber;
2998  else
2999  elog(ERROR, "unexpected strategy number %d", op_strategy);
3000  new_ops = NIL;
3001  forthree(opfamilies_cell, opfamilies,
3002  lefttypes_cell, lefttypes,
3003  righttypes_cell, righttypes)
3004  {
3005  Oid opfam = lfirst_oid(opfamilies_cell);
3006  Oid lefttype = lfirst_oid(lefttypes_cell);
3007  Oid righttype = lfirst_oid(righttypes_cell);
3008 
3009  expr_op = get_opfamily_member(opfam, lefttype, righttype,
3010  op_strategy);
3011  if (!OidIsValid(expr_op)) /* should not happen */
3012  elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
3013  op_strategy, lefttype, righttype, opfam);
3014  new_ops = lappend_oid(new_ops, expr_op);
3015  }
3016  }
3017 
3018  /* If we have more than one matching col, create a subset rowcompare */
3019  if (matching_cols > 1)
3020  {
3022 
3023  rc->rctype = (RowCompareType) op_strategy;
3024  rc->opnos = new_ops;
3025  rc->opfamilies = list_copy_head(clause->opfamilies,
3026  matching_cols);
3027  rc->inputcollids = list_copy_head(clause->inputcollids,
3028  matching_cols);
3029  rc->largs = list_copy_head(var_args, matching_cols);
3030  rc->rargs = list_copy_head(non_var_args, matching_cols);
3032  (Expr *) rc));
3033  }
3034  else
3035  {
3036  Expr *op;
3037 
3038  /* We don't report an index column list in this case */
3039  iclause->indexcols = NIL;
3040 
3041  op = make_opclause(linitial_oid(new_ops), BOOLOID, false,
3042  copyObject(linitial(var_args)),
3043  copyObject(linitial(non_var_args)),
3044  InvalidOid,
3045  linitial_oid(clause->inputcollids));
3046  iclause->indexquals = list_make1(make_simple_restrictinfo(root, op));
3047  }
3048  }
3049 
3050  return iclause;
3051 }
3052 
3053 
3054 /****************************************************************************
3055  * ---- ROUTINES TO CHECK ORDERING OPERATORS ----
3056  ****************************************************************************/
3057 
3058 /*
3059  * match_pathkeys_to_index
3060  * For the given 'index' and 'pathkeys', output a list of suitable ORDER
3061  * BY expressions, each of the form "indexedcol operator pseudoconstant",
3062  * along with an integer list of the index column numbers (zero based)
3063  * that each clause would be used with.
3064  *
3065  * This attempts to find an ORDER BY and index column number for all items in
3066  * the pathkey list, however, if we're unable to match any given pathkey to an
3067  * index column, we return just the ones matched by the function so far. This
3068  * allows callers who are interested in partial matches to get them. Callers
3069  * can determine a partial match vs a full match by checking the outputted
3070  * list lengths. A full match will have one item in the output lists for each
3071  * item in the given 'pathkeys' list.
3072  */
3073 static void
3075  List **orderby_clauses_p,
3076  List **clause_columns_p)
3077 {
3078  ListCell *lc1;
3079 
3080  *orderby_clauses_p = NIL; /* set default results */
3081  *clause_columns_p = NIL;
3082 
3083  /* Only indexes with the amcanorderbyop property are interesting here */
3084  if (!index->amcanorderbyop)
3085  return;
3086 
3087  foreach(lc1, pathkeys)
3088  {
3089  PathKey *pathkey = (PathKey *) lfirst(lc1);
3090  bool found = false;
3091  ListCell *lc2;
3092 
3093 
3094  /* Pathkey must request default sort order for the target opfamily */
3095  if (pathkey->pk_strategy != BTLessStrategyNumber ||
3096  pathkey->pk_nulls_first)
3097  return;
3098 
3099  /* If eclass is volatile, no hope of using an indexscan */
3100  if (pathkey->pk_eclass->ec_has_volatile)
3101  return;
3102 
3103  /*
3104  * Try to match eclass member expression(s) to index. Note that child
3105  * EC members are considered, but only when they belong to the target
3106  * relation. (Unlike regular members, the same expression could be a
3107  * child member of more than one EC. Therefore, the same index could
3108  * be considered to match more than one pathkey list, which is OK
3109  * here. See also get_eclass_for_sort_expr.)
3110  */
3111  foreach(lc2, pathkey->pk_eclass->ec_members)
3112  {
3113  EquivalenceMember *member = (EquivalenceMember *) lfirst(lc2);
3114  int indexcol;
3115 
3116  /* No possibility of match if it references other relations */
3117  if (!bms_equal(member->em_relids, index->rel->relids))
3118  continue;
3119 
3120  /*
3121  * We allow any column of the index to match each pathkey; they
3122  * don't have to match left-to-right as you might expect. This is
3123  * correct for GiST, and it doesn't matter for SP-GiST because
3124  * that doesn't handle multiple columns anyway, and no other
3125  * existing AMs support amcanorderbyop. We might need different
3126  * logic in future for other implementations.
3127  */
3128  for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
3129  {
3130  Expr *expr;
3131 
3133  indexcol,
3134  member->em_expr,
3135  pathkey->pk_opfamily);
3136  if (expr)
3137  {
3138  *orderby_clauses_p = lappend(*orderby_clauses_p, expr);
3139  *clause_columns_p = lappend_int(*clause_columns_p, indexcol);
3140  found = true;
3141  break;
3142  }
3143  }
3144 
3145  if (found) /* don't want to look at remaining members */
3146  break;
3147  }
3148 
3149  /*
3150  * Return the matches found so far when this pathkey couldn't be
3151  * matched to the index.
3152  */
3153  if (!found)
3154  return;
3155  }
3156 }
3157 
3158 /*
3159  * match_clause_to_ordering_op
3160  * Determines whether an ordering operator expression matches an
3161  * index column.
3162  *
3163  * This is similar to, but simpler than, match_clause_to_indexcol.
3164  * We only care about simple OpExpr cases. The input is a bare
3165  * expression that is being ordered by, which must be of the form
3166  * (indexkey op const) or (const op indexkey) where op is an ordering
3167  * operator for the column's opfamily.
3168  *
3169  * 'index' is the index of interest.
3170  * 'indexcol' is a column number of 'index' (counting from 0).
3171  * 'clause' is the ordering expression to be tested.
3172  * 'pk_opfamily' is the btree opfamily describing the required sort order.
3173  *
3174  * Note that we currently do not consider the collation of the ordering
3175  * operator's result. In practical cases the result type will be numeric
3176  * and thus have no collation, and it's not very clear what to match to
3177  * if it did have a collation. The index's collation should match the
3178  * ordering operator's input collation, not its result.
3179  *
3180  * If successful, return 'clause' as-is if the indexkey is on the left,
3181  * otherwise a commuted copy of 'clause'. If no match, return NULL.
3182  */
3183 static Expr *
3185  int indexcol,
3186  Expr *clause,
3187  Oid pk_opfamily)
3188 {
3189  Oid opfamily;
3190  Oid idxcollation;
3191  Node *leftop,
3192  *rightop;
3193  Oid expr_op;
3194  Oid expr_coll;
3195  Oid sortfamily;
3196  bool commuted;
3197 
3198  Assert(indexcol < index->nkeycolumns);
3199 
3200  opfamily = index->opfamily[indexcol];
3201  idxcollation = index->indexcollations[indexcol];
3202 
3203  /*
3204  * Clause must be a binary opclause.
3205  */
3206  if (!is_opclause(clause))
3207  return NULL;
3208  leftop = get_leftop(clause);
3209  rightop = get_rightop(clause);
3210  if (!leftop || !rightop)
3211  return NULL;
3212  expr_op = ((OpExpr *) clause)->opno;
3213  expr_coll = ((OpExpr *) clause)->inputcollid;
3214 
3215  /*
3216  * We can forget the whole thing right away if wrong collation.
3217  */
3218  if (!IndexCollMatchesExprColl(idxcollation, expr_coll))
3219  return NULL;
3220 
3221  /*
3222  * Check for clauses of the form: (indexkey operator constant) or
3223  * (constant operator indexkey).
3224  */
3225  if (match_index_to_operand(leftop, indexcol, index) &&
3226  !contain_var_clause(rightop) &&
3227  !contain_volatile_functions(rightop))
3228  {
3229  commuted = false;
3230  }
3231  else if (match_index_to_operand(rightop, indexcol, index) &&
3232  !contain_var_clause(leftop) &&
3233  !contain_volatile_functions(leftop))
3234  {
3235  /* Might match, but we need a commuted operator */
3236  expr_op = get_commutator(expr_op);
3237  if (expr_op == InvalidOid)
3238  return NULL;
3239  commuted = true;
3240  }
3241  else
3242  return NULL;
3243 
3244  /*
3245  * Is the (commuted) operator an ordering operator for the opfamily? And
3246  * if so, does it yield the right sorting semantics?
3247  */
3248  sortfamily = get_op_opfamily_sortfamily(expr_op, opfamily);
3249  if (sortfamily != pk_opfamily)
3250  return NULL;
3251 
3252  /* We have a match. Return clause or a commuted version thereof. */
3253  if (commuted)
3254  {
3255  OpExpr *newclause = makeNode(OpExpr);
3256 
3257  /* flat-copy all the fields of clause */
3258  memcpy(newclause, clause, sizeof(OpExpr));
3259 
3260  /* commute it */
3261  newclause->opno = expr_op;
3262  newclause->opfuncid = InvalidOid;
3263  newclause->args = list_make2(rightop, leftop);
3264 
3265  clause = (Expr *) newclause;
3266  }
3267 
3268  return clause;
3269 }
3270 
3271 
3272 /****************************************************************************
3273  * ---- ROUTINES TO DO PARTIAL INDEX PREDICATE TESTS ----
3274  ****************************************************************************/
3275 
3276 /*
3277  * check_index_predicates
3278  * Set the predicate-derived IndexOptInfo fields for each index
3279  * of the specified relation.
3280  *
3281  * predOK is set true if the index is partial and its predicate is satisfied
3282  * for this query, ie the query's WHERE clauses imply the predicate.
3283  *
3284  * indrestrictinfo is set to the relation's baserestrictinfo list less any
3285  * conditions that are implied by the index's predicate. (Obviously, for a
3286  * non-partial index, this is the same as baserestrictinfo.) Such conditions
3287  * can be dropped from the plan when using the index, in certain cases.
3288  *
3289  * At one time it was possible for this to get re-run after adding more
3290  * restrictions to the rel, thus possibly letting us prove more indexes OK.
3291  * That doesn't happen any more (at least not in the core code's usage),
3292  * but this code still supports it in case extensions want to mess with the
3293  * baserestrictinfo list. We assume that adding more restrictions can't make
3294  * an index not predOK. We must recompute indrestrictinfo each time, though,
3295  * to make sure any newly-added restrictions get into it if needed.
3296  */
3297 void
3299 {
3300  List *clauselist;
3301  bool have_partial;
3302  bool is_target_rel;
3303  Relids otherrels;
3304  ListCell *lc;
3305 
3306  /* Indexes are available only on base or "other" member relations. */
3307  Assert(IS_SIMPLE_REL(rel));
3308 
3309  /*
3310  * Initialize the indrestrictinfo lists to be identical to
3311  * baserestrictinfo, and check whether there are any partial indexes. If
3312  * not, this is all we need to do.
3313  */
3314  have_partial = false;
3315  foreach(lc, rel->indexlist)
3316  {
3318 
3319  index->indrestrictinfo = rel->baserestrictinfo;
3320  if (index->indpred)
3321  have_partial = true;
3322  }
3323  if (!have_partial)
3324  return;
3325 
3326  /*
3327  * Construct a list of clauses that we can assume true for the purpose of
3328  * proving the index(es) usable. Restriction clauses for the rel are
3329  * always usable, and so are any join clauses that are "movable to" this
3330  * rel. Also, we can consider any EC-derivable join clauses (which must
3331  * be "movable to" this rel, by definition).
3332  */
3333  clauselist = list_copy(rel->baserestrictinfo);
3334 
3335  /* Scan the rel's join clauses */
3336  foreach(lc, rel->joininfo)
3337  {
3338  RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
3339 
3340  /* Check if clause can be moved to this rel */
3341  if (!join_clause_is_movable_to(rinfo, rel))
3342  continue;
3343 
3344  clauselist = lappend(clauselist, rinfo);
3345  }
3346 
3347  /*
3348  * Add on any equivalence-derivable join clauses. Computing the correct
3349  * relid sets for generate_join_implied_equalities is slightly tricky
3350  * because the rel could be a child rel rather than a true baserel, and in
3351  * that case we must subtract its parents' relid(s) from all_query_rels.
3352  * Additionally, we mustn't consider clauses that are only computable
3353  * after outer joins that can null the rel.
3354  */
3355  if (rel->reloptkind == RELOPT_OTHER_MEMBER_REL)
3356  otherrels = bms_difference(root->all_query_rels,
3357  find_childrel_parents(root, rel));
3358  else
3359  otherrels = bms_difference(root->all_query_rels, rel->relids);
3360  otherrels = bms_del_members(otherrels, rel->nulling_relids);
3361 
3362  if (!bms_is_empty(otherrels))
3363  clauselist =
3364  list_concat(clauselist,
3366  bms_union(rel->relids,
3367  otherrels),
3368  otherrels,
3369  rel,
3370  NULL));
3371 
3372  /*
3373  * Normally we remove quals that are implied by a partial index's
3374  * predicate from indrestrictinfo, indicating that they need not be
3375  * checked explicitly by an indexscan plan using this index. However, if
3376  * the rel is a target relation of UPDATE/DELETE/MERGE/SELECT FOR UPDATE,
3377  * we cannot remove such quals from the plan, because they need to be in
3378  * the plan so that they will be properly rechecked by EvalPlanQual
3379  * testing. Some day we might want to remove such quals from the main
3380  * plan anyway and pass them through to EvalPlanQual via a side channel;
3381  * but for now, we just don't remove implied quals at all for target
3382  * relations.
3383  */
3384  is_target_rel = (bms_is_member(rel->relid, root->all_result_relids) ||
3385  get_plan_rowmark(root->rowMarks, rel->relid) != NULL);
3386 
3387  /*
3388  * Now try to prove each index predicate true, and compute the
3389  * indrestrictinfo lists for partial indexes. Note that we compute the
3390  * indrestrictinfo list even for non-predOK indexes; this might seem
3391  * wasteful, but we may be able to use such indexes in OR clauses, cf
3392  * generate_bitmap_or_paths().
3393  */
3394  foreach(lc, rel->indexlist)
3395  {
3397  ListCell *lcr;
3398 
3399  if (index->indpred == NIL)
3400  continue; /* ignore non-partial indexes here */
3401 
3402  if (!index->predOK) /* don't repeat work if already proven OK */
3403  index->predOK = predicate_implied_by(index->indpred, clauselist,
3404  false);
3405 
3406  /* If rel is an update target, leave indrestrictinfo as set above */
3407  if (is_target_rel)
3408  continue;
3409 
3410  /* Else compute indrestrictinfo as the non-implied quals */
3411  index->indrestrictinfo = NIL;
3412  foreach(lcr, rel->baserestrictinfo)
3413  {
3414  RestrictInfo *rinfo = (RestrictInfo *) lfirst(lcr);
3415 
3416  /* predicate_implied_by() assumes first arg is immutable */
3417  if (contain_mutable_functions((Node *) rinfo->clause) ||
3419  index->indpred, false))
3420  index->indrestrictinfo = lappend(index->indrestrictinfo, rinfo);
3421  }
3422  }
3423 }
3424 
3425 /****************************************************************************
3426  * ---- ROUTINES TO CHECK EXTERNALLY-VISIBLE CONDITIONS ----
3427  ****************************************************************************/
3428 
3429 /*
3430  * ec_member_matches_indexcol
3431  * Test whether an EquivalenceClass member matches an index column.
3432  *
3433  * This is a callback for use by generate_implied_equalities_for_column.
3434  */
3435 static bool
3438  void *arg)
3439 {
3440  IndexOptInfo *index = ((ec_member_matches_arg *) arg)->index;
3441  int indexcol = ((ec_member_matches_arg *) arg)->indexcol;
3442  Oid curFamily;
3443  Oid curCollation;
3444 
3445  Assert(indexcol < index->nkeycolumns);
3446 
3447  curFamily = index->opfamily[indexcol];
3448  curCollation = index->indexcollations[indexcol];
3449 
3450  /*
3451  * If it's a btree index, we can reject it if its opfamily isn't
3452  * compatible with the EC, since no clause generated from the EC could be
3453  * used with the index. For non-btree indexes, we can't easily tell
3454  * whether clauses generated from the EC could be used with the index, so
3455  * don't check the opfamily. This might mean we return "true" for a
3456  * useless EC, so we have to recheck the results of
3457  * generate_implied_equalities_for_column; see
3458  * match_eclass_clauses_to_index.
3459  */
3460  if (index->relam == BTREE_AM_OID &&
3461  !list_member_oid(ec->ec_opfamilies, curFamily))
3462  return false;
3463 
3464  /* We insist on collation match for all index types, though */
3465  if (!IndexCollMatchesExprColl(curCollation, ec->ec_collation))
3466  return false;
3467 
3468  return match_index_to_operand((Node *) em->em_expr, indexcol, index);
3469 }
3470 
3471 /*
3472  * relation_has_unique_index_for
3473  * Determine whether the relation provably has at most one row satisfying
3474  * a set of equality conditions, because the conditions constrain all
3475  * columns of some unique index.
3476  *
3477  * The conditions can be represented in either or both of two ways:
3478  * 1. A list of RestrictInfo nodes, where the caller has already determined
3479  * that each condition is a mergejoinable equality with an expression in
3480  * this relation on one side, and an expression not involving this relation
3481  * on the other. The transient outer_is_left flag is used to identify which
3482  * side we should look at: left side if outer_is_left is false, right side
3483  * if it is true.
3484  * 2. A list of expressions in this relation, and a corresponding list of
3485  * equality operators. The caller must have already checked that the operators
3486  * represent equality. (Note: the operators could be cross-type; the
3487  * expressions should correspond to their RHS inputs.)
3488  *
3489  * The caller need only supply equality conditions arising from joins;
3490  * this routine automatically adds in any usable baserestrictinfo clauses.
3491  * (Note that the passed-in restrictlist will be destructively modified!)
3492  */
3493 bool
3495  List *restrictlist,
3496  List *exprlist, List *oprlist)
3497 {
3498  return relation_has_unique_index_ext(root, rel, restrictlist,
3499  exprlist, oprlist, NULL);
3500 }
3501 
3502 /*
3503  * relation_has_unique_index_ext
3504  * Same as relation_has_unique_index_for(), but supports extra_clauses
3505  * parameter. If extra_clauses isn't NULL, return baserestrictinfo clauses
3506  * which were used to derive uniqueness.
3507  */
3508 bool
3510  List *restrictlist,
3511  List *exprlist, List *oprlist,
3512  List **extra_clauses)
3513 {
3514  ListCell *ic;
3515 
3516  Assert(list_length(exprlist) == list_length(oprlist));
3517 
3518  /* Short-circuit if no indexes... */
3519  if (rel->indexlist == NIL)
3520  return false;
3521 
3522  /*
3523  * Examine the rel's restriction clauses for usable var = const clauses
3524  * that we can add to the restrictlist.
3525  */
3526  foreach(ic, rel->baserestrictinfo)
3527  {
3528  RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(ic);
3529 
3530  /*
3531  * Note: can_join won't be set for a restriction clause, but
3532  * mergeopfamilies will be if it has a mergejoinable operator and
3533  * doesn't contain volatile functions.
3534  */
3535  if (restrictinfo->mergeopfamilies == NIL)
3536  continue; /* not mergejoinable */
3537 
3538  /*
3539  * The clause certainly doesn't refer to anything but the given rel.
3540  * If either side is pseudoconstant then we can use it.
3541  */
3542  if (bms_is_empty(restrictinfo->left_relids))
3543  {
3544  /* righthand side is inner */
3545  restrictinfo->outer_is_left = true;
3546  }
3547  else if (bms_is_empty(restrictinfo->right_relids))
3548  {
3549  /* lefthand side is inner */
3550  restrictinfo->outer_is_left = false;
3551  }
3552  else
3553  continue;
3554 
3555  /* OK, add to list */
3556  restrictlist = lappend(restrictlist, restrictinfo);
3557  }
3558 
3559  /* Short-circuit the easy case */
3560  if (restrictlist == NIL && exprlist == NIL)
3561  return false;
3562 
3563  /* Examine each index of the relation ... */
3564  foreach(ic, rel->indexlist)
3565  {
3566  IndexOptInfo *ind = (IndexOptInfo *) lfirst(ic);
3567  int c;
3568  List *exprs = NIL;
3569 
3570  /*
3571  * If the index is not unique, or not immediately enforced, or if it's
3572  * a partial index, it's useless here. We're unable to make use of
3573  * predOK partial unique indexes due to the fact that
3574  * check_index_predicates() also makes use of join predicates to
3575  * determine if the partial index is usable. Here we need proofs that
3576  * hold true before any joins are evaluated.
3577  */
3578  if (!ind->unique || !ind->immediate || ind->indpred != NIL)
3579  continue;
3580 
3581  /*
3582  * Try to find each index column in the lists of conditions. This is
3583  * O(N^2) or worse, but we expect all the lists to be short.
3584  */
3585  for (c = 0; c < ind->nkeycolumns; c++)
3586  {
3587  bool matched = false;
3588  ListCell *lc;
3589  ListCell *lc2;
3590 
3591  foreach(lc, restrictlist)
3592  {
3593  RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
3594  Node *rexpr;
3595 
3596  /*
3597  * The condition's equality operator must be a member of the
3598  * index opfamily, else it is not asserting the right kind of
3599  * equality behavior for this index. We check this first
3600  * since it's probably cheaper than match_index_to_operand().
3601  */
3602  if (!list_member_oid(rinfo->mergeopfamilies, ind->opfamily[c]))
3603  continue;
3604 
3605  /*
3606  * XXX at some point we may need to check collations here too.
3607  * For the moment we assume all collations reduce to the same
3608  * notion of equality.
3609  */
3610 
3611  /* OK, see if the condition operand matches the index key */
3612  if (rinfo->outer_is_left)
3613  rexpr = get_rightop(rinfo->clause);
3614  else
3615  rexpr = get_leftop(rinfo->clause);
3616 
3617  if (match_index_to_operand(rexpr, c, ind))
3618  {
3619  matched = true; /* column is unique */
3620 
3621  if (bms_membership(rinfo->clause_relids) == BMS_SINGLETON)
3622  {
3623  MemoryContext oldMemCtx =
3624  MemoryContextSwitchTo(root->planner_cxt);
3625 
3626  /*
3627  * Add filter clause into a list allowing caller to
3628  * know if uniqueness have made not only by join
3629  * clauses.
3630  */
3631  Assert(bms_is_empty(rinfo->left_relids) ||
3632  bms_is_empty(rinfo->right_relids));
3633  if (extra_clauses)
3634  exprs = lappend(exprs, rinfo);
3635  MemoryContextSwitchTo(oldMemCtx);
3636  }
3637 
3638  break;
3639  }
3640  }
3641 
3642  if (matched)
3643  continue;
3644 
3645  forboth(lc, exprlist, lc2, oprlist)
3646  {
3647  Node *expr = (Node *) lfirst(lc);
3648  Oid opr = lfirst_oid(lc2);
3649 
3650  /* See if the expression matches the index key */
3651  if (!match_index_to_operand(expr, c, ind))
3652  continue;
3653 
3654  /*
3655  * The equality operator must be a member of the index
3656  * opfamily, else it is not asserting the right kind of
3657  * equality behavior for this index. We assume the caller
3658  * determined it is an equality operator, so we don't need to
3659  * check any more tightly than this.
3660  */
3661  if (!op_in_opfamily(opr, ind->opfamily[c]))
3662  continue;
3663 
3664  /*
3665  * XXX at some point we may need to check collations here too.
3666  * For the moment we assume all collations reduce to the same
3667  * notion of equality.
3668  */
3669 
3670  matched = true; /* column is unique */
3671  break;
3672  }
3673 
3674  if (!matched)
3675  break; /* no match; this index doesn't help us */
3676  }
3677 
3678  /* Matched all key columns of this index? */
3679  if (c == ind->nkeycolumns)
3680  {
3681  if (extra_clauses)
3682  *extra_clauses = exprs;
3683  return true;
3684  }
3685  }
3686 
3687  return false;
3688 }
3689 
3690 /*
3691  * indexcol_is_bool_constant_for_query
3692  *
3693  * If an index column is constrained to have a constant value by the query's
3694  * WHERE conditions, then it's irrelevant for sort-order considerations.
3695  * Usually that means we have a restriction clause WHERE indexcol = constant,
3696  * which gets turned into an EquivalenceClass containing a constant, which
3697  * is recognized as redundant by build_index_pathkeys(). But if the index
3698  * column is a boolean variable (or expression), then we are not going to
3699  * see WHERE indexcol = constant, because expression preprocessing will have
3700  * simplified that to "WHERE indexcol" or "WHERE NOT indexcol". So we are not
3701  * going to have a matching EquivalenceClass (unless the query also contains
3702  * "ORDER BY indexcol"). To allow such cases to work the same as they would
3703  * for non-boolean values, this function is provided to detect whether the
3704  * specified index column matches a boolean restriction clause.
3705  */
3706 bool
3709  int indexcol)
3710 {
3711  ListCell *lc;
3712 
3713  /* If the index isn't boolean, we can't possibly get a match */
3714  if (!IsBooleanOpfamily(index->opfamily[indexcol]))
3715  return false;
3716 
3717  /* Check each restriction clause for the index's rel */
3718  foreach(lc, index->rel->baserestrictinfo)
3719  {
3720  RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
3721 
3722  /*
3723  * As in match_clause_to_indexcol, never match pseudoconstants to
3724  * indexes. (It might be semantically okay to do so here, but the
3725  * odds of getting a match are negligible, so don't waste the cycles.)
3726  */
3727  if (rinfo->pseudoconstant)
3728  continue;
3729 
3730  /* See if we can match the clause's expression to the index column */
3731  if (match_boolean_index_clause(root, rinfo, indexcol, index))
3732  return true;
3733  }
3734 
3735  return false;
3736 }
3737 
3738 
3739 /****************************************************************************
3740  * ---- ROUTINES TO CHECK OPERANDS ----
3741  ****************************************************************************/
3742 
3743 /*
3744  * match_index_to_operand()
3745  * Generalized test for a match between an index's key
3746  * and the operand on one side of a restriction or join clause.
3747  *
3748  * operand: the nodetree to be compared to the index
3749  * indexcol: the column number of the index (counting from 0)
3750  * index: the index of interest
3751  *
3752  * Note that we aren't interested in collations here; the caller must check
3753  * for a collation match, if it's dealing with an operator where that matters.
3754  *
3755  * This is exported for use in selfuncs.c.
3756  */
3757 bool
3759  int indexcol,
3761 {
3762  int indkey;
3763 
3764  /*
3765  * Ignore any RelabelType node above the operand. This is needed to be
3766  * able to apply indexscanning in binary-compatible-operator cases. Note:
3767  * we can assume there is at most one RelabelType node;
3768  * eval_const_expressions() will have simplified if more than one.
3769  */
3770  if (operand && IsA(operand, RelabelType))
3771  operand = (Node *) ((RelabelType *) operand)->arg;
3772 
3773  indkey = index->indexkeys[indexcol];
3774  if (indkey != 0)
3775  {
3776  /*
3777  * Simple index column; operand must be a matching Var.
3778  */
3779  if (operand && IsA(operand, Var) &&
3780  index->rel->relid == ((Var *) operand)->varno &&
3781  indkey == ((Var *) operand)->varattno &&
3782  ((Var *) operand)->varnullingrels == NULL)
3783  return true;
3784  }
3785  else
3786  {
3787  /*
3788  * Index expression; find the correct expression. (This search could
3789  * be avoided, at the cost of complicating all the callers of this
3790  * routine; doesn't seem worth it.)
3791  */
3792  ListCell *indexpr_item;
3793  int i;
3794  Node *indexkey;
3795 
3796  indexpr_item = list_head(index->indexprs);
3797  for (i = 0; i < indexcol; i++)
3798  {
3799  if (index->indexkeys[i] == 0)
3800  {
3801  if (indexpr_item == NULL)
3802  elog(ERROR, "wrong number of index expressions");
3803  indexpr_item = lnext(index->indexprs, indexpr_item);
3804  }
3805  }
3806  if (indexpr_item == NULL)
3807  elog(ERROR, "wrong number of index expressions");
3808  indexkey = (Node *) lfirst(indexpr_item);
3809 
3810  /*
3811  * Does it match the operand? Again, strip any relabeling.
3812  */
3813  if (indexkey && IsA(indexkey, RelabelType))
3814  indexkey = (Node *) ((RelabelType *) indexkey)->arg;
3815 
3816  if (equal(indexkey, operand))
3817  return true;
3818  }
3819 
3820  return false;
3821 }
3822 
3823 /*
3824  * is_pseudo_constant_for_index()
3825  * Test whether the given expression can be used as an indexscan
3826  * comparison value.
3827  *
3828  * An indexscan comparison value must not contain any volatile functions,
3829  * and it can't contain any Vars of the index's own table. Vars of
3830  * other tables are okay, though; in that case we'd be producing an
3831  * indexqual usable in a parameterized indexscan. This is, therefore,
3832  * a weaker condition than is_pseudo_constant_clause().
3833  *
3834  * This function is exported for use by planner support functions,
3835  * which will have available the IndexOptInfo, but not any RestrictInfo
3836  * infrastructure. It is making the same test made by functions above
3837  * such as match_opclause_to_indexcol(), but those rely where possible
3838  * on RestrictInfo information about variable membership.
3839  *
3840  * expr: the nodetree to be checked
3841  * index: the index of interest
3842  */
3843 bool
3845 {
3846  /* pull_varnos is cheaper than volatility check, so do that first */
3847  if (bms_is_member(index->rel->relid, pull_varnos(root, expr)))
3848  return false; /* no good, contains Var of table */
3849  if (contain_volatile_functions(expr))
3850  return false; /* no good, volatile comparison value */
3851  return true;
3852 }
void create_partial_bitmap_paths(PlannerInfo *root, RelOptInfo *rel, Path *bitmapqual)
Definition: allpaths.c:4174
bool bms_equal(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:155
BMS_Comparison bms_subset_compare(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:458
int bms_next_member(const Bitmapset *a, int prevbit)
Definition: bitmapset.c:1319
bool bms_is_subset(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:425
void bms_free(Bitmapset *a)
Definition: bitmapset.c:252
bool bms_is_member(int x, const Bitmapset *a)
Definition: bitmapset.c:523
Bitmapset * bms_add_member(Bitmapset *a, int x)
Definition: bitmapset.c:828
Bitmapset * bms_union(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:264
Bitmapset * bms_difference(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:359
Bitmapset * bms_add_members(Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:930
Bitmapset * bms_del_members(Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:1174
Bitmapset * bms_del_member(Bitmapset *a, int x)
Definition: bitmapset.c:881
BMS_Membership bms_membership(const Bitmapset *a)
Definition: bitmapset.c:794
bool bms_overlap(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:595
Bitmapset * bms_copy(const Bitmapset *a)
Definition: bitmapset.c:135
#define bms_is_empty(a)
Definition: bitmapset.h:105
@ BMS_DIFFERENT
Definition: bitmapset.h:65
@ BMS_SINGLETON
Definition: bitmapset.h:72
unsigned int Index
Definition: c.h:601
#define MemSet(start, val, len)
Definition: c.h:1007
#define OidIsValid(objectId)
Definition: c.h:762
bool contain_mutable_functions(Node *clause)
Definition: clauses.c:369
bool contain_volatile_functions(Node *clause)
Definition: clauses.c:518
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:1013
bool enable_indexonlyscan
Definition: costsize.c:136
#define ERROR
Definition: elog.h:39
#define elog(elevel,...)
Definition: elog.h:224
bool equal(const void *a, const void *b)
Definition: equalfuncs.c:223
List * generate_join_implied_equalities(PlannerInfo *root, Relids join_relids, Relids outer_relids, RelOptInfo *inner_rel, SpecialJoinInfo *sjinfo)
Definition: equivclass.c:1392
List * generate_implied_equalities_for_column(PlannerInfo *root, RelOptInfo *rel, ec_matches_callback_type callback, void *callback_arg, Relids prohibited_rels)
Definition: equivclass.c:2895
#define OidFunctionCall1(functionId, arg1)
Definition: fmgr.h:680
static bool IsBooleanOpfamily(Oid opfamily)
Definition: indxpath.c:2334
static Path * choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel, List *paths)
Definition: indxpath.c:1341
static Cost bitmap_and_cost_est(PlannerInfo *root, RelOptInfo *rel, List *paths)
Definition: indxpath.c:1614
static void find_indexpath_quals(Path *bitmapqual, List **quals, List **preds)
Definition: indxpath.c:1711
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:601
static List * build_index_paths(PlannerInfo *root, RelOptInfo *rel, IndexOptInfo *index, IndexClauseSet *clauses, bool useful_predicate, ScanTypeControl scantype, bool *skip_nonnative_saop, bool *skip_lower_saop)
Definition: indxpath.c:835
static void match_clause_to_index(PlannerInfo *root, RestrictInfo *rinfo, IndexOptInfo *index, IndexClauseSet *clauseset)
Definition: indxpath.c:2138
bool is_pseudo_constant_for_index(PlannerInfo *root, Node *expr, IndexOptInfo *index)
Definition: indxpath.c:3844
static bool eclass_already_used(EquivalenceClass *parent_ec, Relids oldrelids, List *indexjoinclauses)
Definition: indxpath.c:679
static void match_join_clauses_to_index(PlannerInfo *root, RelOptInfo *rel, IndexOptInfo *index, IndexClauseSet *clauseset, List **joinorclauses)
Definition: indxpath.c:2037
static IndexClause * match_saopclause_to_indexcol(PlannerInfo *root, RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
Definition: indxpath.c:2677
static bool check_index_only(RelOptInfo *rel, IndexOptInfo *index)
Definition: indxpath.c:1784
static void match_eclass_clauses_to_index(PlannerInfo *root, IndexOptInfo *index, IndexClauseSet *clauseset)
Definition: indxpath.c:2067
ScanTypeControl
Definition: indxpath.c:45
@ ST_ANYSCAN
Definition: indxpath.c:48
@ ST_BITMAPSCAN
Definition: indxpath.c:47
@ ST_INDEXSCAN
Definition: indxpath.c:46
static PathClauseUsage * classify_index_clause_usage(Path *path, List **clauselist)
Definition: indxpath.c:1643
static void get_index_paths(PlannerInfo *root, RelOptInfo *rel, IndexOptInfo *index, IndexClauseSet *clauses, List **bitindexpaths)
Definition: indxpath.c:713
void check_index_predicates(PlannerInfo *root, RelOptInfo *rel)
Definition: indxpath.c:3298
static void match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys, List **orderby_clauses_p, List **clause_columns_p)
Definition: indxpath.c:3074
static int find_list_position(Node *node, List **nodelist)
Definition: indxpath.c:1758
static void match_clauses_to_index(PlannerInfo *root, List *clauses, IndexOptInfo *index, IndexClauseSet *clauseset)
Definition: indxpath.c:2105
static double get_loop_count(PlannerInfo *root, Index cur_relid, Relids outer_relids)
Definition: indxpath.c:1883
bool relation_has_unique_index_for(PlannerInfo *root, RelOptInfo *rel, List *restrictlist, List *exprlist, List *oprlist)
Definition: indxpath.c:3494
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:498
void create_index_paths(PlannerInfo *root, RelOptInfo *rel)
Definition: indxpath.c:235
static double adjust_rowcount_for_semijoins(PlannerInfo *root, Index cur_relid, Index outer_relid, double rowcount)
Definition: indxpath.c:1936
static IndexClause * match_clause_to_indexcol(PlannerInfo *root, RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
Definition: indxpath.c:2257
static bool ec_member_matches_indexcol(PlannerInfo *root, RelOptInfo *rel, EquivalenceClass *ec, EquivalenceMember *em, void *arg)
Definition: indxpath.c:3436
static IndexClause * get_index_clause_from_support(PlannerInfo *root, RestrictInfo *rinfo, Oid funcid, int indexarg, int indexcol, IndexOptInfo *index)
Definition: indxpath.c:2611
#define IndexCollMatchesExprColl(idxcollation, exprcollation)
Definition: indxpath.c:40
static IndexClause * match_opclause_to_indexcol(PlannerInfo *root, RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
Definition: indxpath.c:2446
static Cost bitmap_scan_cost_est(PlannerInfo *root, RelOptInfo *rel, Path *ipath)
Definition: indxpath.c:1580
bool match_index_to_operand(Node *operand, int indexcol, IndexOptInfo *index)
Definition: indxpath.c:3758
static IndexClause * match_boolean_index_clause(PlannerInfo *root, RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
Definition: indxpath.c:2359
static void consider_index_join_clauses(PlannerInfo *root, RelOptInfo *rel, IndexOptInfo *index, IndexClauseSet *rclauseset, IndexClauseSet *jclauseset, IndexClauseSet *eclauseset, List **bitindexpaths)
Definition: indxpath.c:432
static IndexClause * expand_indexqual_rowcompare(PlannerInfo *root, RestrictInfo *rinfo, int indexcol, IndexOptInfo *index, Oid expr_op, bool var_on_left)
Definition: indxpath.c:2852
static void match_restriction_clauses_to_index(PlannerInfo *root, IndexOptInfo *index, IndexClauseSet *clauseset)
Definition: indxpath.c:2022
static IndexClause * match_rowcompare_to_indexcol(PlannerInfo *root, RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
Definition: indxpath.c:2745
static List * build_paths_for_OR(PlannerInfo *root, RelOptInfo *rel, List *clauses, List *other_clauses)
Definition: indxpath.c:1139
bool indexcol_is_bool_constant_for_query(PlannerInfo *root, IndexOptInfo *index, int indexcol)
Definition: indxpath.c:3707
bool relation_has_unique_index_ext(PlannerInfo *root, RelOptInfo *rel, List *restrictlist, List *exprlist, List *oprlist, List **extra_clauses)
Definition: indxpath.c:3509
static IndexClause * match_funcclause_to_indexcol(PlannerInfo *root, RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
Definition: indxpath.c:2565
static int path_usage_comparator(const void *a, const void *b)
Definition: indxpath.c:1547
static double approximate_joinrel_size(PlannerInfo *root, Relids relids)
Definition: indxpath.c:1980
static Expr * match_clause_to_ordering_op(IndexOptInfo *index, int indexcol, Expr *clause, Oid pk_opfamily)
Definition: indxpath.c:3184
static List * generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel, List *clauses, List *other_clauses)
Definition: indxpath.c:1234
int b
Definition: isn.c:70
int a
Definition: isn.c:69
int j
Definition: isn.c:74
int i
Definition: isn.c:73
if(TABLE==NULL||TABLE_index==NULL)
Definition: isn.c:77
Assert(fmt[strlen(fmt) - 1] !='\n')
List * list_truncate(List *list, int new_size)
Definition: list.c:631
List * lappend(List *list, void *datum)
Definition: list.c:339
List * list_copy_head(const List *oldlist, int len)
Definition: list.c:1593
List * lappend_int(List *list, int datum)
Definition: list.c:357
List * lappend_oid(List *list, Oid datum)
Definition: list.c:375
List * list_copy(const List *oldlist)
Definition: list.c:1573
List * list_append_unique(List *list, void *datum)
Definition: list.c:1343
void list_free(List *list)
Definition: list.c:1546
bool list_member_oid(const List *list, Oid datum)
Definition: list.c:722
List * list_concat(List *list1, const List *list2)
Definition: list.c:561
bool list_member(const List *list, const void *datum)
Definition: list.c:661
List * list_concat_copy(const List *list1, const List *list2)
Definition: list.c:598
void get_op_opfamily_properties(Oid opno, Oid opfamily, bool ordering_op, int *strategy, Oid *lefttype, Oid *righttype)
Definition: lsyscache.c:136
Oid get_op_opfamily_sortfamily(Oid opno, Oid opfamily)
Definition: lsyscache.c:108
RegProcedure get_func_support(Oid funcid)
Definition: lsyscache.c:1836
int get_op_opfamily_strategy(Oid opno, Oid opfamily)
Definition: lsyscache.c:83
Oid get_opfamily_member(Oid opfamily, Oid lefttype, Oid righttype, int16 strategy)
Definition: lsyscache.c:166
bool op_in_opfamily(Oid opno, Oid opfamily)
Definition: lsyscache.c:66
Oid get_commutator(Oid opno)
Definition: lsyscache.c:1487
Expr * make_opclause(Oid opno, Oid opresulttype, bool opretset, Expr *leftop, Expr *rightop, Oid opcollid, Oid inputcollid)
Definition: makefuncs.c:612
Node * makeBoolConst(bool value, bool isnull)
Definition: makefuncs.c:359
void pfree(void *pointer)
Definition: mcxt.c:1401
void * palloc(Size size)
Definition: mcxt.c:1197
void set_opfuncid(OpExpr *opexpr)
Definition: nodeFuncs.c:1778
static bool is_andclause(const void *clause)
Definition: nodeFuncs.h:105
static Expr * get_notclausearg(const void *notclause)
Definition: nodeFuncs.h:132
static bool is_opclause(const void *clause)
Definition: nodeFuncs.h:74
static Node * get_rightop(const void *clause)
Definition: nodeFuncs.h:93
static bool is_notclause(const void *clause)
Definition: nodeFuncs.h:123
static Node * get_leftop(const void *clause)
Definition: nodeFuncs.h:81
#define IsA(nodeptr, _type_)
Definition: nodes.h:158
#define copyObject(obj)
Definition: nodes.h:223
double Cost
Definition: nodes.h:241
#define nodeTag(nodeptr)
Definition: nodes.h:133
double Selectivity
Definition: nodes.h:240
#define makeNode(_type_)
Definition: nodes.h:155
#define castNode(_type_, nodeptr)
Definition: nodes.h:176
@ JOIN_SEMI
Definition: nodes.h:297
static MemoryContext MemoryContextSwitchTo(MemoryContext context)
Definition: palloc.h:124
bool has_useful_pathkeys(PlannerInfo *root, RelOptInfo *rel)
Definition: pathkeys.c:2242
List * truncate_useless_pathkeys(PlannerInfo *root, RelOptInfo *rel, List *pathkeys)
Definition: pathkeys.c:2199
List * build_index_pathkeys(PlannerInfo *root, IndexOptInfo *index, ScanDirection scandir)
Definition: pathkeys.c:755
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:991
void add_partial_path(RelOptInfo *parent_rel, Path *new_path)
Definition: pathnode.c:745
BitmapOrPath * create_bitmap_or_path(PlannerInfo *root, RelOptInfo *rel, List *bitmapquals)
Definition: pathnode.c:1125
void add_path(RelOptInfo *parent_rel, Path *new_path)
Definition: pathnode.c:418
BitmapAndPath * create_bitmap_and_path(PlannerInfo *root, RelOptInfo *rel, List *bitmapquals)
Definition: pathnode.c:1073
BitmapHeapPath * create_bitmap_heap_path(PlannerInfo *root, RelOptInfo *rel, Path *bitmapqual, Relids required_outer, double loop_count, int parallel_degree)
Definition: pathnode.c:1040
#define IS_SIMPLE_REL(rel)
Definition: pathnodes.h:824
#define IS_DUMMY_REL(r)
Definition: pathnodes.h:1926
#define PATH_REQ_OUTER(path)
Definition: pathnodes.h:1649
Bitmapset * Relids
Definition: pathnodes.h:30
@ RELOPT_OTHER_MEMBER_REL
Definition: pathnodes.h:814
void * arg
#define INDEX_MAX_KEYS
#define lfirst(lc)
Definition: pg_list.h:172
#define lfirst_node(type, lc)
Definition: pg_list.h:176
static int list_length(const List *l)
Definition: pg_list.h:152
#define NIL
Definition: pg_list.h:68
#define forboth(cell1, list1, cell2, list2)
Definition: pg_list.h:518
static Oid list_nth_oid(const List *list, int n)
Definition: pg_list.h:321
#define list_make1_oid(x1)
Definition: pg_list.h:242
#define list_make1(x1)
Definition: pg_list.h:212
#define forthree(cell1, list1, cell2, list2, cell3, list3)
Definition: pg_list.h:563
static ListCell * list_head(const List *l)
Definition: pg_list.h:128
#define linitial(l)
Definition: pg_list.h:178
#define lsecond(l)
Definition: pg_list.h:183
static void * list_nth(const List *list, int n)
Definition: pg_list.h:299
static ListCell * lnext(const List *l, const ListCell *c)
Definition: pg_list.h:343
#define list_make1_int(x1)
Definition: pg_list.h:227
#define linitial_oid(l)
Definition: pg_list.h:180
#define lfirst_oid(lc)
Definition: pg_list.h:174
#define list_make2(x1, x2)
Definition: pg_list.h:214
#define qsort(a, b, c, d)
Definition: port.h:449
static Datum PointerGetDatum(const void *X)
Definition: postgres.h:322
static Pointer DatumGetPointer(Datum X)
Definition: postgres.h:312
#define InvalidOid
Definition: postgres_ext.h:36
unsigned int Oid
Definition: postgres_ext.h:31
bool predicate_implied_by(List *predicate_list, List *clause_list, bool weak)
Definition: predtest.c:152
char * c
PlanRowMark * get_plan_rowmark(List *rowmarks, Index rtindex)
Definition: preptlist.c:485
@ IS_TRUE
Definition: primnodes.h:1718
@ IS_FALSE
Definition: primnodes.h:1718
RowCompareType
Definition: primnodes.h:1388
Relids find_childrel_parents(PlannerInfo *root, RelOptInfo *rel)
Definition: relnode.c:1514
bool restriction_is_or_clause(RestrictInfo *restrictinfo)
Definition: restrictinfo.c:416
RestrictInfo * commute_restrictinfo(RestrictInfo *rinfo, Oid comm_op)
Definition: restrictinfo.c:359
bool restriction_is_securely_promotable(RestrictInfo *restrictinfo, RelOptInfo *rel)
Definition: restrictinfo.c:431
bool join_clause_is_movable_to(RestrictInfo *rinfo, RelOptInfo *baserel)
Definition: restrictinfo.c:584
#define make_simple_restrictinfo(root, clause)
Definition: restrictinfo.h:21
@ BackwardScanDirection
Definition: sdir.h:26
@ ForwardScanDirection
Definition: sdir.h:28
double estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows, List **pgset, EstimationInfo *estinfo)
Definition: selfuncs.c:3416
#define BTGreaterStrategyNumber
Definition: stratnum.h:33
#define BTLessStrategyNumber
Definition: stratnum.h:29
#define BTLessEqualStrategyNumber
Definition: stratnum.h:30
#define BTGreaterEqualStrategyNumber
Definition: stratnum.h:32
List * bitmapquals
Definition: pathnodes.h:1777
Path * bitmapqual
Definition: pathnodes.h:1765
List * bitmapquals
Definition: pathnodes.h:1790
BoolTestType booltesttype
Definition: primnodes.h:1725
Expr * arg
Definition: primnodes.h:1724
List * ec_opfamilies
Definition: pathnodes.h:1370
Oid funcid
Definition: primnodes.h:685
List * args
Definition: primnodes.h:703
bool nonempty
Definition: indxpath.c:54
List * indexclauses[INDEX_MAX_KEYS]
Definition: indxpath.c:56
AttrNumber indexcol
Definition: pathnodes.h:1741
List * indexcols
Definition: pathnodes.h:1742
List * indexquals
Definition: pathnodes.h:1739
struct RestrictInfo * rinfo
Definition: pathnodes.h:1738
List * indpred
Definition: pathnodes.h:1152
List * indexclauses
Definition: pathnodes.h:1691
Path path
Definition: pathnodes.h:1689
Selectivity indexselectivity
Definition: pathnodes.h:1696
IndexOptInfo * indexinfo
Definition: pathnodes.h:1690
Definition: pg_list.h:54
Definition: nodes.h:129
Expr * arg
Definition: primnodes.h:1700
Oid opno
Definition: primnodes.h:753
List * args
Definition: primnodes.h:771
List * quals
Definition: indxpath.c:63
List * preds
Definition: indxpath.c:64
Bitmapset * clauseids
Definition: indxpath.c:65
bool unclassifiable
Definition: indxpath.c:66
Path * path
Definition: indxpath.c:62
bool pk_nulls_first
Definition: pathnodes.h:1458
int pk_strategy
Definition: pathnodes.h:1457
Oid pk_opfamily
Definition: pathnodes.h:1456
List * exprs
Definition: pathnodes.h:1513
List * pathkeys
Definition: pathnodes.h:1645
NodeTag pathtype
Definition: pathnodes.h:1606
int parallel_workers
Definition: pathnodes.h:1637
Cost total_cost
Definition: pathnodes.h:1642
int simple_rel_array_size
Definition: pathnodes.h:229
Relids all_query_rels
Definition: pathnodes.h:266
List * rowMarks
Definition: pathnodes.h:368
List * query_pathkeys
Definition: pathnodes.h:382
List * join_info_list
Definition: pathnodes.h:337
Relids all_result_relids
Definition: pathnodes.h:351
List * baserestrictinfo
Definition: pathnodes.h:966
List * joininfo
Definition: pathnodes.h:972
Relids relids
Definition: pathnodes.h:856
struct PathTarget * reltarget
Definition: pathnodes.h:878
Index relid
Definition: pathnodes.h:903
bool consider_parallel
Definition: pathnodes.h:872
Relids lateral_relids
Definition: pathnodes.h:898
RelOptKind reloptkind
Definition: pathnodes.h:850
List * indexlist
Definition: pathnodes.h:925
Relids nulling_relids
Definition: pathnodes.h:919
Cardinality rows
Definition: pathnodes.h:862
Expr * clause
Definition: pathnodes.h:2541
RowCompareType rctype
Definition: primnodes.h:1403
Relids syn_lefthand
Definition: pathnodes.h:2870
List * semi_rhs_exprs
Definition: pathnodes.h:2883
JoinType jointype
Definition: pathnodes.h:2872
Relids syn_righthand
Definition: pathnodes.h:2871
struct IndexOptInfo * index
Definition: supportnodes.h:232
struct PlannerInfo * root
Definition: supportnodes.h:228
Definition: primnodes.h:234
IndexOptInfo * index
Definition: indxpath.c:72
Definition: type.h:95
#define FirstLowInvalidHeapAttributeNumber
Definition: sysattr.h:27
#define FirstNormalObjectId
Definition: transam.h:197
bool contain_var_clause(Node *node)
Definition: var.c:403
Relids pull_varnos(PlannerInfo *root, Node *node)
Definition: var.c:108
void pull_varattnos(Node *node, Index varno, Bitmapset **varattnos)
Definition: var.c:291