Line data Source code
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) 1996-2026, 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 "access/transam.h"
23 : #include "catalog/pg_am.h"
24 : #include "catalog/pg_amop.h"
25 : #include "catalog/pg_operator.h"
26 : #include "catalog/pg_opfamily.h"
27 : #include "catalog/pg_type.h"
28 : #include "nodes/makefuncs.h"
29 : #include "nodes/nodeFuncs.h"
30 : #include "nodes/supportnodes.h"
31 : #include "optimizer/cost.h"
32 : #include "optimizer/optimizer.h"
33 : #include "optimizer/pathnode.h"
34 : #include "optimizer/paths.h"
35 : #include "optimizer/prep.h"
36 : #include "optimizer/restrictinfo.h"
37 : #include "utils/lsyscache.h"
38 : #include "utils/selfuncs.h"
39 :
40 :
41 : /* XXX see PartCollMatchesExprColl */
42 : #define IndexCollMatchesExprColl(idxcollation, exprcollation) \
43 : ((idxcollation) == InvalidOid || (idxcollation) == (exprcollation))
44 :
45 : /* Whether we are looking for plain indexscan, bitmap scan, or either */
46 : typedef enum
47 : {
48 : ST_INDEXSCAN, /* must support amgettuple */
49 : ST_BITMAPSCAN, /* must support amgetbitmap */
50 : ST_ANYSCAN, /* either is okay */
51 : } ScanTypeControl;
52 :
53 : /* Data structure for collecting qual clauses that match an index */
54 : typedef struct
55 : {
56 : bool nonempty; /* True if lists are not all empty */
57 : /* Lists of IndexClause nodes, one list per index column */
58 : List *indexclauses[INDEX_MAX_KEYS];
59 : } IndexClauseSet;
60 :
61 : /* Per-path data used within choose_bitmap_and() */
62 : typedef struct
63 : {
64 : Path *path; /* IndexPath, BitmapAndPath, or BitmapOrPath */
65 : List *quals; /* the WHERE clauses it uses */
66 : List *preds; /* predicates of its partial index(es) */
67 : Bitmapset *clauseids; /* quals+preds represented as a bitmapset */
68 : bool unclassifiable; /* has too many quals+preds to process? */
69 : } PathClauseUsage;
70 :
71 : /* Callback argument for ec_member_matches_indexcol */
72 : typedef struct
73 : {
74 : IndexOptInfo *index; /* index we're considering */
75 : int indexcol; /* index column we want to match to */
76 : } ec_member_matches_arg;
77 :
78 :
79 : static void consider_index_join_clauses(PlannerInfo *root, RelOptInfo *rel,
80 : IndexOptInfo *index,
81 : IndexClauseSet *rclauseset,
82 : IndexClauseSet *jclauseset,
83 : IndexClauseSet *eclauseset,
84 : List **bitindexpaths);
85 : static void consider_index_join_outer_rels(PlannerInfo *root, RelOptInfo *rel,
86 : IndexOptInfo *index,
87 : IndexClauseSet *rclauseset,
88 : IndexClauseSet *jclauseset,
89 : IndexClauseSet *eclauseset,
90 : List **bitindexpaths,
91 : List *indexjoinclauses,
92 : int considered_clauses,
93 : List **considered_relids);
94 : static void get_join_index_paths(PlannerInfo *root, RelOptInfo *rel,
95 : IndexOptInfo *index,
96 : IndexClauseSet *rclauseset,
97 : IndexClauseSet *jclauseset,
98 : IndexClauseSet *eclauseset,
99 : List **bitindexpaths,
100 : Relids relids,
101 : List **considered_relids);
102 : static bool eclass_already_used(EquivalenceClass *parent_ec, Relids oldrelids,
103 : List *indexjoinclauses);
104 : static void get_index_paths(PlannerInfo *root, RelOptInfo *rel,
105 : IndexOptInfo *index, IndexClauseSet *clauses,
106 : List **bitindexpaths);
107 : static List *build_index_paths(PlannerInfo *root, RelOptInfo *rel,
108 : IndexOptInfo *index, IndexClauseSet *clauses,
109 : bool useful_predicate,
110 : ScanTypeControl scantype,
111 : bool *skip_nonnative_saop);
112 : static List *build_paths_for_OR(PlannerInfo *root, RelOptInfo *rel,
113 : List *clauses, List *other_clauses);
114 : static List *generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel,
115 : List *clauses, List *other_clauses);
116 : static Path *choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel,
117 : List *paths);
118 : static int path_usage_comparator(const void *a, const void *b);
119 : static Cost bitmap_scan_cost_est(PlannerInfo *root, RelOptInfo *rel,
120 : Path *ipath);
121 : static Cost bitmap_and_cost_est(PlannerInfo *root, RelOptInfo *rel,
122 : List *paths);
123 : static PathClauseUsage *classify_index_clause_usage(Path *path,
124 : List **clauselist);
125 : static void find_indexpath_quals(Path *bitmapqual, List **quals, List **preds);
126 : static int find_list_position(Node *node, List **nodelist);
127 : static bool check_index_only(RelOptInfo *rel, IndexOptInfo *index);
128 : static double get_loop_count(PlannerInfo *root, Index cur_relid, Relids outer_relids);
129 : static double adjust_rowcount_for_semijoins(PlannerInfo *root,
130 : Index cur_relid,
131 : Index outer_relid,
132 : double rowcount);
133 : static double approximate_joinrel_size(PlannerInfo *root, Relids relids);
134 : static void match_restriction_clauses_to_index(PlannerInfo *root,
135 : IndexOptInfo *index,
136 : IndexClauseSet *clauseset);
137 : static void match_join_clauses_to_index(PlannerInfo *root,
138 : RelOptInfo *rel, IndexOptInfo *index,
139 : IndexClauseSet *clauseset,
140 : List **joinorclauses);
141 : static void match_eclass_clauses_to_index(PlannerInfo *root,
142 : IndexOptInfo *index,
143 : IndexClauseSet *clauseset);
144 : static void match_clauses_to_index(PlannerInfo *root,
145 : List *clauses,
146 : IndexOptInfo *index,
147 : IndexClauseSet *clauseset);
148 : static void match_clause_to_index(PlannerInfo *root,
149 : RestrictInfo *rinfo,
150 : IndexOptInfo *index,
151 : IndexClauseSet *clauseset);
152 : static IndexClause *match_clause_to_indexcol(PlannerInfo *root,
153 : RestrictInfo *rinfo,
154 : int indexcol,
155 : IndexOptInfo *index);
156 : static bool IsBooleanOpfamily(Oid opfamily);
157 : static IndexClause *match_boolean_index_clause(PlannerInfo *root,
158 : RestrictInfo *rinfo,
159 : int indexcol, IndexOptInfo *index);
160 : static IndexClause *match_opclause_to_indexcol(PlannerInfo *root,
161 : RestrictInfo *rinfo,
162 : int indexcol,
163 : IndexOptInfo *index);
164 : static IndexClause *match_funcclause_to_indexcol(PlannerInfo *root,
165 : RestrictInfo *rinfo,
166 : int indexcol,
167 : IndexOptInfo *index);
168 : static IndexClause *get_index_clause_from_support(PlannerInfo *root,
169 : RestrictInfo *rinfo,
170 : Oid funcid,
171 : int indexarg,
172 : int indexcol,
173 : IndexOptInfo *index);
174 : static IndexClause *match_saopclause_to_indexcol(PlannerInfo *root,
175 : RestrictInfo *rinfo,
176 : int indexcol,
177 : IndexOptInfo *index);
178 : static IndexClause *match_rowcompare_to_indexcol(PlannerInfo *root,
179 : RestrictInfo *rinfo,
180 : int indexcol,
181 : IndexOptInfo *index);
182 : static IndexClause *match_orclause_to_indexcol(PlannerInfo *root,
183 : RestrictInfo *rinfo,
184 : int indexcol,
185 : IndexOptInfo *index);
186 : static IndexClause *expand_indexqual_rowcompare(PlannerInfo *root,
187 : RestrictInfo *rinfo,
188 : int indexcol,
189 : IndexOptInfo *index,
190 : Oid expr_op,
191 : bool var_on_left);
192 : static void match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys,
193 : List **orderby_clauses_p,
194 : List **clause_columns_p);
195 : static Expr *match_clause_to_ordering_op(IndexOptInfo *index,
196 : int indexcol, Expr *clause, Oid pk_opfamily);
197 : static bool ec_member_matches_indexcol(PlannerInfo *root, RelOptInfo *rel,
198 : EquivalenceClass *ec, EquivalenceMember *em,
199 : void *arg);
200 : static bool contain_strippable_phv_walker(Node *node, void *context);
201 : static Node *strip_phvs_in_index_operand_mutator(Node *node, void *context);
202 :
203 :
204 : /*
205 : * create_index_paths()
206 : * Generate all interesting index paths for the given relation.
207 : * Candidate paths are added to the rel's pathlist (using add_path).
208 : *
209 : * To be considered for an index scan, an index must match one or more
210 : * restriction clauses or join clauses from the query's qual condition,
211 : * or match the query's ORDER BY condition, or have a predicate that
212 : * matches the query's qual condition.
213 : *
214 : * There are two basic kinds of index scans. A "plain" index scan uses
215 : * only restriction clauses (possibly none at all) in its indexqual,
216 : * so it can be applied in any context. A "parameterized" index scan uses
217 : * join clauses (plus restriction clauses, if available) in its indexqual.
218 : * When joining such a scan to one of the relations supplying the other
219 : * variables used in its indexqual, the parameterized scan must appear as
220 : * the inner relation of a nestloop join; it can't be used on the outer side,
221 : * nor in a merge or hash join. In that context, values for the other rels'
222 : * attributes are available and fixed during any one scan of the indexpath.
223 : *
224 : * An IndexPath is generated and submitted to add_path() for each plain or
225 : * parameterized index scan this routine deems potentially interesting for
226 : * the current query.
227 : *
228 : * 'rel' is the relation for which we want to generate index paths
229 : *
230 : * Note: check_index_predicates() must have been run previously for this rel.
231 : *
232 : * Note: in cases involving LATERAL references in the relation's tlist, it's
233 : * possible that rel->lateral_relids is nonempty. Currently, we include
234 : * lateral_relids into the parameterization reported for each path, but don't
235 : * take it into account otherwise. The fact that any such rels *must* be
236 : * available as parameter sources perhaps should influence our choices of
237 : * index quals ... but for now, it doesn't seem worth troubling over.
238 : * In particular, comments below about "unparameterized" paths should be read
239 : * as meaning "unparameterized so far as the indexquals are concerned".
240 : */
241 : void
242 417082 : create_index_paths(PlannerInfo *root, RelOptInfo *rel)
243 : {
244 : List *indexpaths;
245 : List *bitindexpaths;
246 : List *bitjoinpaths;
247 : List *joinorclauses;
248 : IndexClauseSet rclauseset;
249 : IndexClauseSet jclauseset;
250 : IndexClauseSet eclauseset;
251 : ListCell *lc;
252 :
253 : /* Skip the whole mess if no indexes */
254 417082 : if (rel->indexlist == NIL)
255 72250 : return;
256 :
257 : /* Bitmap paths are collected and then dealt with at the end */
258 344832 : bitindexpaths = bitjoinpaths = joinorclauses = NIL;
259 :
260 : /* Examine each index in turn */
261 1079162 : foreach(lc, rel->indexlist)
262 : {
263 734330 : IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
264 :
265 : /* Protect limited-size array in IndexClauseSets */
266 : Assert(index->nkeycolumns <= INDEX_MAX_KEYS);
267 :
268 : /*
269 : * Ignore partial indexes that do not match the query.
270 : * (generate_bitmap_or_paths() might be able to do something with
271 : * them, but that's of no concern here.)
272 : */
273 734330 : if (index->indpred != NIL && !index->predOK)
274 548 : continue;
275 :
276 : /*
277 : * Identify the restriction clauses that can match the index.
278 : */
279 24948588 : MemSet(&rclauseset, 0, sizeof(rclauseset));
280 733782 : match_restriction_clauses_to_index(root, index, &rclauseset);
281 :
282 : /*
283 : * Build index paths from the restriction clauses. These will be
284 : * non-parameterized paths. Plain paths go directly to add_path(),
285 : * bitmap paths are added to bitindexpaths to be handled below.
286 : */
287 733782 : get_index_paths(root, rel, index, &rclauseset,
288 : &bitindexpaths);
289 :
290 : /*
291 : * Identify the join clauses that can match the index. For the moment
292 : * we keep them separate from the restriction clauses. Note that this
293 : * step finds only "loose" join clauses that have not been merged into
294 : * EquivalenceClasses. Also, collect join OR clauses for later.
295 : */
296 24948588 : MemSet(&jclauseset, 0, sizeof(jclauseset));
297 733782 : match_join_clauses_to_index(root, rel, index,
298 : &jclauseset, &joinorclauses);
299 :
300 : /*
301 : * Look for EquivalenceClasses that can generate joinclauses matching
302 : * the index.
303 : */
304 24948588 : MemSet(&eclauseset, 0, sizeof(eclauseset));
305 733782 : match_eclass_clauses_to_index(root, index,
306 : &eclauseset);
307 :
308 : /*
309 : * If we found any plain or eclass join clauses, build parameterized
310 : * index paths using them.
311 : */
312 733782 : if (jclauseset.nonempty || eclauseset.nonempty)
313 142806 : consider_index_join_clauses(root, rel, index,
314 : &rclauseset,
315 : &jclauseset,
316 : &eclauseset,
317 : &bitjoinpaths);
318 : }
319 :
320 : /*
321 : * Generate BitmapOrPaths for any suitable OR-clauses present in the
322 : * restriction list. Add these to bitindexpaths.
323 : */
324 344832 : indexpaths = generate_bitmap_or_paths(root, rel,
325 : rel->baserestrictinfo, NIL);
326 344832 : bitindexpaths = list_concat(bitindexpaths, indexpaths);
327 :
328 : /*
329 : * Likewise, generate BitmapOrPaths for any suitable OR-clauses present in
330 : * the joinclause list. Add these to bitjoinpaths.
331 : */
332 344832 : indexpaths = generate_bitmap_or_paths(root, rel,
333 : joinorclauses, rel->baserestrictinfo);
334 344832 : bitjoinpaths = list_concat(bitjoinpaths, indexpaths);
335 :
336 : /*
337 : * If we found anything usable, generate a BitmapHeapPath for the most
338 : * promising combination of restriction bitmap index paths. Note there
339 : * will be only one such path no matter how many indexes exist. This
340 : * should be sufficient since there's basically only one figure of merit
341 : * (total cost) for such a path.
342 : */
343 344832 : if (bitindexpaths != NIL)
344 : {
345 : Path *bitmapqual;
346 : BitmapHeapPath *bpath;
347 :
348 208604 : bitmapqual = choose_bitmap_and(root, rel, bitindexpaths);
349 208604 : bpath = create_bitmap_heap_path(root, rel, bitmapqual,
350 : rel->lateral_relids, 1.0, 0);
351 208604 : add_path(rel, (Path *) bpath);
352 :
353 : /* create a partial bitmap heap path */
354 208604 : if (rel->consider_parallel && rel->lateral_relids == NULL)
355 146438 : create_partial_bitmap_paths(root, rel, bitmapqual);
356 : }
357 :
358 : /*
359 : * Likewise, if we found anything usable, generate BitmapHeapPaths for the
360 : * most promising combinations of join bitmap index paths. Our strategy
361 : * is to generate one such path for each distinct parameterization seen
362 : * among the available bitmap index paths. This may look pretty
363 : * expensive, but usually there won't be very many distinct
364 : * parameterizations. (This logic is quite similar to that in
365 : * consider_index_join_clauses, but we're working with whole paths not
366 : * individual clauses.)
367 : */
368 344832 : if (bitjoinpaths != NIL)
369 : {
370 : List *all_path_outers;
371 :
372 : /* Identify each distinct parameterization seen in bitjoinpaths */
373 129950 : all_path_outers = NIL;
374 286794 : foreach(lc, bitjoinpaths)
375 : {
376 156844 : Path *path = (Path *) lfirst(lc);
377 156844 : Relids required_outer = PATH_REQ_OUTER(path);
378 :
379 156844 : all_path_outers = list_append_unique(all_path_outers,
380 : required_outer);
381 : }
382 :
383 : /* Now, for each distinct parameterization set ... */
384 279496 : foreach(lc, all_path_outers)
385 : {
386 149546 : Relids max_outers = (Relids) lfirst(lc);
387 : List *this_path_set;
388 : Path *bitmapqual;
389 : Relids required_outer;
390 : double loop_count;
391 : BitmapHeapPath *bpath;
392 : ListCell *lcp;
393 :
394 : /* Identify all the bitmap join paths needing no more than that */
395 149546 : this_path_set = NIL;
396 359088 : foreach(lcp, bitjoinpaths)
397 : {
398 209542 : Path *path = (Path *) lfirst(lcp);
399 :
400 209542 : if (bms_is_subset(PATH_REQ_OUTER(path), max_outers))
401 164020 : this_path_set = lappend(this_path_set, path);
402 : }
403 :
404 : /*
405 : * Add in restriction bitmap paths, since they can be used
406 : * together with any join paths.
407 : */
408 149546 : this_path_set = list_concat(this_path_set, bitindexpaths);
409 :
410 : /* Select best AND combination for this parameterization */
411 149546 : bitmapqual = choose_bitmap_and(root, rel, this_path_set);
412 :
413 : /* And push that path into the mix */
414 149546 : required_outer = PATH_REQ_OUTER(bitmapqual);
415 149546 : loop_count = get_loop_count(root, rel->relid, required_outer);
416 149546 : bpath = create_bitmap_heap_path(root, rel, bitmapqual,
417 : required_outer, loop_count, 0);
418 149546 : add_path(rel, (Path *) bpath);
419 : }
420 : }
421 : }
422 :
423 : /*
424 : * consider_index_join_clauses
425 : * Given sets of join clauses for an index, decide which parameterized
426 : * index paths to build.
427 : *
428 : * Plain indexpaths are sent directly to add_path, while potential
429 : * bitmap indexpaths are added to *bitindexpaths for later processing.
430 : *
431 : * 'rel' is the index's heap relation
432 : * 'index' is the index for which we want to generate paths
433 : * 'rclauseset' is the collection of indexable restriction clauses
434 : * 'jclauseset' is the collection of indexable simple join clauses
435 : * 'eclauseset' is the collection of indexable clauses from EquivalenceClasses
436 : * '*bitindexpaths' is the list to add bitmap paths to
437 : */
438 : static void
439 142806 : consider_index_join_clauses(PlannerInfo *root, RelOptInfo *rel,
440 : IndexOptInfo *index,
441 : IndexClauseSet *rclauseset,
442 : IndexClauseSet *jclauseset,
443 : IndexClauseSet *eclauseset,
444 : List **bitindexpaths)
445 : {
446 142806 : int considered_clauses = 0;
447 142806 : List *considered_relids = NIL;
448 : int indexcol;
449 :
450 : /*
451 : * The strategy here is to identify every potentially useful set of outer
452 : * rels that can provide indexable join clauses. For each such set,
453 : * select all the join clauses available from those outer rels, add on all
454 : * the indexable restriction clauses, and generate plain and/or bitmap
455 : * index paths for that set of clauses. This is based on the assumption
456 : * that it's always better to apply a clause as an indexqual than as a
457 : * filter (qpqual); which is where an available clause would end up being
458 : * applied if we omit it from the indexquals.
459 : *
460 : * This looks expensive, but in most practical cases there won't be very
461 : * many distinct sets of outer rels to consider. As a safety valve when
462 : * that's not true, we use a heuristic: limit the number of outer rel sets
463 : * considered to a multiple of the number of clauses considered. (We'll
464 : * always consider using each individual join clause, though.)
465 : *
466 : * For simplicity in selecting relevant clauses, we represent each set of
467 : * outer rels as a maximum set of clause_relids --- that is, the indexed
468 : * relation itself is also included in the relids set. considered_relids
469 : * lists all relids sets we've already tried.
470 : */
471 363524 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
472 : {
473 : /* Consider each applicable simple join clause */
474 220718 : considered_clauses += list_length(jclauseset->indexclauses[indexcol]);
475 220718 : consider_index_join_outer_rels(root, rel, index,
476 : rclauseset, jclauseset, eclauseset,
477 : bitindexpaths,
478 : jclauseset->indexclauses[indexcol],
479 : considered_clauses,
480 : &considered_relids);
481 : /* Consider each applicable eclass join clause */
482 220718 : considered_clauses += list_length(eclauseset->indexclauses[indexcol]);
483 220718 : consider_index_join_outer_rels(root, rel, index,
484 : rclauseset, jclauseset, eclauseset,
485 : bitindexpaths,
486 : eclauseset->indexclauses[indexcol],
487 : considered_clauses,
488 : &considered_relids);
489 : }
490 142806 : }
491 :
492 : /*
493 : * consider_index_join_outer_rels
494 : * Generate parameterized paths based on clause relids in the clause list.
495 : *
496 : * Workhorse for consider_index_join_clauses; see notes therein for rationale.
497 : *
498 : * 'rel', 'index', 'rclauseset', 'jclauseset', 'eclauseset', and
499 : * 'bitindexpaths' as above
500 : * 'indexjoinclauses' is a list of IndexClauses for join clauses
501 : * 'considered_clauses' is the total number of clauses considered (so far)
502 : * '*considered_relids' is a list of all relids sets already considered
503 : */
504 : static void
505 441436 : consider_index_join_outer_rels(PlannerInfo *root, RelOptInfo *rel,
506 : IndexOptInfo *index,
507 : IndexClauseSet *rclauseset,
508 : IndexClauseSet *jclauseset,
509 : IndexClauseSet *eclauseset,
510 : List **bitindexpaths,
511 : List *indexjoinclauses,
512 : int considered_clauses,
513 : List **considered_relids)
514 : {
515 : ListCell *lc;
516 :
517 : /* Examine relids of each joinclause in the given list */
518 602850 : foreach(lc, indexjoinclauses)
519 : {
520 161414 : IndexClause *iclause = (IndexClause *) lfirst(lc);
521 161414 : Relids clause_relids = iclause->rinfo->clause_relids;
522 161414 : EquivalenceClass *parent_ec = iclause->rinfo->parent_ec;
523 : int num_considered_relids;
524 :
525 : /* If we already tried its relids set, no need to do so again */
526 161414 : if (list_member(*considered_relids, clause_relids))
527 8064 : continue;
528 :
529 : /*
530 : * Generate the union of this clause's relids set with each
531 : * previously-tried set. This ensures we try this clause along with
532 : * every interesting subset of previous clauses. However, to avoid
533 : * exponential growth of planning time when there are many clauses,
534 : * limit the number of relid sets accepted to 10 * considered_clauses.
535 : *
536 : * Note: get_join_index_paths appends entries to *considered_relids,
537 : * but we do not need to visit such newly-added entries within this
538 : * loop, so we don't use foreach() here. No real harm would be done
539 : * if we did visit them, since the subset check would reject them; but
540 : * it would waste some cycles.
541 : */
542 153350 : num_considered_relids = list_length(*considered_relids);
543 164260 : for (int pos = 0; pos < num_considered_relids; pos++)
544 : {
545 10910 : Relids oldrelids = (Relids) list_nth(*considered_relids, pos);
546 :
547 : /*
548 : * If either is a subset of the other, no new set is possible.
549 : * This isn't a complete test for redundancy, but it's easy and
550 : * cheap. get_join_index_paths will check more carefully if we
551 : * already generated the same relids set.
552 : */
553 10910 : if (bms_subset_compare(clause_relids, oldrelids) != BMS_DIFFERENT)
554 24 : continue;
555 :
556 : /*
557 : * If this clause was derived from an equivalence class, the
558 : * clause list may contain other clauses derived from the same
559 : * eclass. We should not consider that combining this clause with
560 : * one of those clauses generates a usefully different
561 : * parameterization; so skip if any clause derived from the same
562 : * eclass would already have been included when using oldrelids.
563 : */
564 21610 : if (parent_ec &&
565 10724 : eclass_already_used(parent_ec, oldrelids,
566 : indexjoinclauses))
567 7388 : continue;
568 :
569 : /*
570 : * If the number of relid sets considered exceeds our heuristic
571 : * limit, stop considering combinations of clauses. We'll still
572 : * consider the current clause alone, though (below this loop).
573 : */
574 3498 : if (list_length(*considered_relids) >= 10 * considered_clauses)
575 0 : break;
576 :
577 : /* OK, try the union set */
578 3498 : get_join_index_paths(root, rel, index,
579 : rclauseset, jclauseset, eclauseset,
580 : bitindexpaths,
581 : bms_union(clause_relids, oldrelids),
582 : considered_relids);
583 : }
584 :
585 : /* Also try this set of relids by itself */
586 153350 : get_join_index_paths(root, rel, index,
587 : rclauseset, jclauseset, eclauseset,
588 : bitindexpaths,
589 : clause_relids,
590 : considered_relids);
591 : }
592 441436 : }
593 :
594 : /*
595 : * get_join_index_paths
596 : * Generate index paths using clauses from the specified outer relations.
597 : * In addition to generating paths, relids is added to *considered_relids
598 : * if not already present.
599 : *
600 : * Workhorse for consider_index_join_clauses; see notes therein for rationale.
601 : *
602 : * 'rel', 'index', 'rclauseset', 'jclauseset', 'eclauseset',
603 : * 'bitindexpaths', 'considered_relids' as above
604 : * 'relids' is the current set of relids to consider (the target rel plus
605 : * one or more outer rels)
606 : */
607 : static void
608 156848 : get_join_index_paths(PlannerInfo *root, RelOptInfo *rel,
609 : IndexOptInfo *index,
610 : IndexClauseSet *rclauseset,
611 : IndexClauseSet *jclauseset,
612 : IndexClauseSet *eclauseset,
613 : List **bitindexpaths,
614 : Relids relids,
615 : List **considered_relids)
616 : {
617 : IndexClauseSet clauseset;
618 : int indexcol;
619 :
620 : /* If we already considered this relids set, don't repeat the work */
621 156848 : if (list_member(*considered_relids, relids))
622 0 : return;
623 :
624 : /* Identify indexclauses usable with this relids set */
625 5332832 : MemSet(&clauseset, 0, sizeof(clauseset));
626 :
627 404428 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
628 : {
629 : ListCell *lc;
630 :
631 : /* First find applicable simple join clauses */
632 283474 : foreach(lc, jclauseset->indexclauses[indexcol])
633 : {
634 35894 : IndexClause *iclause = (IndexClause *) lfirst(lc);
635 :
636 35894 : if (bms_is_subset(iclause->rinfo->clause_relids, relids))
637 35468 : clauseset.indexclauses[indexcol] =
638 35468 : lappend(clauseset.indexclauses[indexcol], iclause);
639 : }
640 :
641 : /*
642 : * Add applicable eclass join clauses. The clauses generated for each
643 : * column are redundant (cf generate_implied_equalities_for_column),
644 : * so we need at most one. This is the only exception to the general
645 : * rule of using all available index clauses.
646 : */
647 264072 : foreach(lc, eclauseset->indexclauses[indexcol])
648 : {
649 149362 : IndexClause *iclause = (IndexClause *) lfirst(lc);
650 :
651 149362 : if (bms_is_subset(iclause->rinfo->clause_relids, relids))
652 : {
653 132870 : clauseset.indexclauses[indexcol] =
654 132870 : lappend(clauseset.indexclauses[indexcol], iclause);
655 132870 : break;
656 : }
657 : }
658 :
659 : /* Add restriction clauses */
660 247580 : clauseset.indexclauses[indexcol] =
661 247580 : list_concat(clauseset.indexclauses[indexcol],
662 247580 : rclauseset->indexclauses[indexcol]);
663 :
664 247580 : if (clauseset.indexclauses[indexcol] != NIL)
665 197004 : clauseset.nonempty = true;
666 : }
667 :
668 : /* We should have found something, else caller passed silly relids */
669 : Assert(clauseset.nonempty);
670 :
671 : /* Build index path(s) using the collected set of clauses */
672 156848 : get_index_paths(root, rel, index, &clauseset, bitindexpaths);
673 :
674 : /*
675 : * Remember we considered paths for this set of relids.
676 : */
677 156848 : *considered_relids = lappend(*considered_relids, relids);
678 : }
679 :
680 : /*
681 : * eclass_already_used
682 : * True if any join clause usable with oldrelids was generated from
683 : * the specified equivalence class.
684 : */
685 : static bool
686 10724 : eclass_already_used(EquivalenceClass *parent_ec, Relids oldrelids,
687 : List *indexjoinclauses)
688 : {
689 : ListCell *lc;
690 :
691 14522 : foreach(lc, indexjoinclauses)
692 : {
693 11186 : IndexClause *iclause = (IndexClause *) lfirst(lc);
694 11186 : RestrictInfo *rinfo = iclause->rinfo;
695 :
696 22372 : if (rinfo->parent_ec == parent_ec &&
697 11186 : bms_is_subset(rinfo->clause_relids, oldrelids))
698 7388 : return true;
699 : }
700 3336 : return false;
701 : }
702 :
703 :
704 : /*
705 : * get_index_paths
706 : * Given an index and a set of index clauses for it, construct IndexPaths.
707 : *
708 : * Plain indexpaths are sent directly to add_path, while potential
709 : * bitmap indexpaths are added to *bitindexpaths for later processing.
710 : *
711 : * This is a fairly simple frontend to build_index_paths(). Its reason for
712 : * existence is mainly to handle ScalarArrayOpExpr quals properly. If the
713 : * index AM supports them natively, we should just include them in simple
714 : * index paths. If not, we should exclude them while building simple index
715 : * paths, and then make a separate attempt to include them in bitmap paths.
716 : */
717 : static void
718 890630 : get_index_paths(PlannerInfo *root, RelOptInfo *rel,
719 : IndexOptInfo *index, IndexClauseSet *clauses,
720 : List **bitindexpaths)
721 : {
722 : List *indexpaths;
723 890630 : bool skip_nonnative_saop = false;
724 : ListCell *lc;
725 :
726 : /*
727 : * Build simple index paths using the clauses. Allow ScalarArrayOpExpr
728 : * clauses only if the index AM supports them natively.
729 : */
730 890630 : indexpaths = build_index_paths(root, rel,
731 : index, clauses,
732 890630 : index->predOK,
733 : ST_ANYSCAN,
734 : &skip_nonnative_saop);
735 :
736 : /*
737 : * Submit all the ones that can form plain IndexScan plans to add_path. (A
738 : * plain IndexPath can represent either a plain IndexScan or an
739 : * IndexOnlyScan, but for our purposes here that distinction does not
740 : * matter. However, some of the indexes might support only bitmap scans,
741 : * and those we mustn't submit to add_path here.)
742 : *
743 : * Also, pick out the ones that are usable as bitmap scans. For that, we
744 : * must discard indexes that don't support bitmap scans, and we also are
745 : * only interested in paths that have some selectivity; we should discard
746 : * anything that was generated solely for ordering purposes.
747 : */
748 1427458 : foreach(lc, indexpaths)
749 : {
750 536828 : IndexPath *ipath = (IndexPath *) lfirst(lc);
751 :
752 536828 : if (index->amhasgettuple)
753 523032 : add_path(rel, (Path *) ipath);
754 :
755 536828 : if (index->amhasgetbitmap &&
756 536828 : (ipath->path.pathkeys == NIL ||
757 333994 : ipath->indexselectivity < 1.0))
758 391794 : *bitindexpaths = lappend(*bitindexpaths, ipath);
759 : }
760 :
761 : /*
762 : * If there were ScalarArrayOpExpr clauses that the index can't handle
763 : * natively, generate bitmap scan paths relying on executor-managed
764 : * ScalarArrayOpExpr.
765 : */
766 890630 : if (skip_nonnative_saop)
767 : {
768 32 : indexpaths = build_index_paths(root, rel,
769 : index, clauses,
770 : false,
771 : ST_BITMAPSCAN,
772 : NULL);
773 32 : *bitindexpaths = list_concat(*bitindexpaths, indexpaths);
774 : }
775 890630 : }
776 :
777 : /*
778 : * build_index_paths
779 : * Given an index and a set of index clauses for it, construct zero
780 : * or more IndexPaths. It also constructs zero or more partial IndexPaths.
781 : *
782 : * We return a list of paths because (1) this routine checks some cases
783 : * that should cause us to not generate any IndexPath, and (2) in some
784 : * cases we want to consider both a forward and a backward scan, so as
785 : * to obtain both sort orders. Note that the paths are just returned
786 : * to the caller and not immediately fed to add_path().
787 : *
788 : * At top level, useful_predicate should be exactly the index's predOK flag
789 : * (ie, true if it has a predicate that was proven from the restriction
790 : * clauses). When working on an arm of an OR clause, useful_predicate
791 : * should be true if the predicate required the current OR list to be proven.
792 : * Note that this routine should never be called at all if the index has an
793 : * unprovable predicate.
794 : *
795 : * scantype indicates whether we want to create plain indexscans, bitmap
796 : * indexscans, or both. When it's ST_BITMAPSCAN, we will not consider
797 : * index ordering while deciding if a Path is worth generating.
798 : *
799 : * If skip_nonnative_saop is non-NULL, we ignore ScalarArrayOpExpr clauses
800 : * unless the index AM supports them directly, and we set *skip_nonnative_saop
801 : * to true if we found any such clauses (caller must initialize the variable
802 : * to false). If it's NULL, we do not ignore ScalarArrayOpExpr clauses.
803 : *
804 : * 'rel' is the index's heap relation
805 : * 'index' is the index for which we want to generate paths
806 : * 'clauses' is the collection of indexable clauses (IndexClause nodes)
807 : * 'useful_predicate' indicates whether the index has a useful predicate
808 : * 'scantype' indicates whether we need plain or bitmap scan support
809 : * 'skip_nonnative_saop' indicates whether to accept SAOP if index AM doesn't
810 : */
811 : static List *
812 893816 : build_index_paths(PlannerInfo *root, RelOptInfo *rel,
813 : IndexOptInfo *index, IndexClauseSet *clauses,
814 : bool useful_predicate,
815 : ScanTypeControl scantype,
816 : bool *skip_nonnative_saop)
817 : {
818 893816 : List *result = NIL;
819 : IndexPath *ipath;
820 : List *index_clauses;
821 : Relids outer_relids;
822 : double loop_count;
823 : List *orderbyclauses;
824 : List *orderbyclausecols;
825 : List *index_pathkeys;
826 : List *useful_pathkeys;
827 : bool pathkeys_possibly_useful;
828 : bool index_is_ordered;
829 : bool index_only_scan;
830 : int indexcol;
831 :
832 : Assert(skip_nonnative_saop != NULL || scantype == ST_BITMAPSCAN);
833 :
834 : /*
835 : * Check that index supports the desired scan type(s)
836 : */
837 893816 : switch (scantype)
838 : {
839 0 : case ST_INDEXSCAN:
840 0 : if (!index->amhasgettuple)
841 0 : return NIL;
842 0 : break;
843 3186 : case ST_BITMAPSCAN:
844 3186 : if (!index->amhasgetbitmap)
845 0 : return NIL;
846 3186 : break;
847 890630 : case ST_ANYSCAN:
848 : /* either or both are OK */
849 890630 : break;
850 : }
851 :
852 : /*
853 : * 1. Combine the per-column IndexClause lists into an overall list.
854 : *
855 : * In the resulting list, clauses are ordered by index key, so that the
856 : * column numbers form a nondecreasing sequence. (This order is depended
857 : * on by btree and possibly other places.) The list can be empty, if the
858 : * index AM allows that.
859 : *
860 : * We also build a Relids set showing which outer rels are required by the
861 : * selected clauses. Any lateral_relids are included in that, but not
862 : * otherwise accounted for.
863 : */
864 893816 : index_clauses = NIL;
865 893816 : outer_relids = bms_copy(rel->lateral_relids);
866 2534518 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
867 : {
868 : ListCell *lc;
869 :
870 2100926 : foreach(lc, clauses->indexclauses[indexcol])
871 : {
872 459880 : IndexClause *iclause = (IndexClause *) lfirst(lc);
873 459880 : RestrictInfo *rinfo = iclause->rinfo;
874 :
875 459880 : if (skip_nonnative_saop && !index->amsearcharray &&
876 21858 : IsA(rinfo->clause, ScalarArrayOpExpr))
877 : {
878 : /*
879 : * Caller asked us to generate IndexPaths that omit any
880 : * ScalarArrayOpExpr clauses when the underlying index AM
881 : * lacks native support.
882 : *
883 : * We must omit this clause (and tell caller about it).
884 : */
885 32 : *skip_nonnative_saop = true;
886 32 : continue;
887 : }
888 :
889 : /* OK to include this clause */
890 459848 : index_clauses = lappend(index_clauses, iclause);
891 459848 : outer_relids = bms_add_members(outer_relids,
892 459848 : rinfo->clause_relids);
893 : }
894 :
895 : /*
896 : * If no clauses match the first index column, check for amoptionalkey
897 : * restriction. We can't generate a scan over an index with
898 : * amoptionalkey = false unless there's at least one index clause.
899 : * (When working on columns after the first, this test cannot fail. It
900 : * is always okay for columns after the first to not have any
901 : * clauses.)
902 : */
903 1641046 : if (index_clauses == NIL && !index->amoptionalkey)
904 344 : return NIL;
905 : }
906 :
907 : /* We do not want the index's rel itself listed in outer_relids */
908 893472 : outer_relids = bms_del_member(outer_relids, rel->relid);
909 :
910 : /* Compute loop_count for cost estimation purposes */
911 893472 : loop_count = get_loop_count(root, rel->relid, outer_relids);
912 :
913 : /*
914 : * 2. Compute pathkeys describing index's ordering, if any, then see how
915 : * many of them are actually useful for this query. This is not relevant
916 : * if we are only trying to build bitmap indexscans.
917 : */
918 1783758 : pathkeys_possibly_useful = (scantype != ST_BITMAPSCAN &&
919 890286 : has_useful_pathkeys(root, rel));
920 893472 : index_is_ordered = (index->sortopfamily != NULL);
921 893472 : if (index_is_ordered && pathkeys_possibly_useful)
922 : {
923 671618 : index_pathkeys = build_index_pathkeys(root, index,
924 : ForwardScanDirection);
925 671618 : useful_pathkeys = truncate_useless_pathkeys(root, rel,
926 : index_pathkeys);
927 671618 : orderbyclauses = NIL;
928 671618 : orderbyclausecols = NIL;
929 : }
930 221854 : else if (index->amcanorderbyop && pathkeys_possibly_useful)
931 : {
932 : /*
933 : * See if we can generate ordering operators for query_pathkeys or at
934 : * least some prefix thereof. Matching to just a prefix of the
935 : * query_pathkeys will allow an incremental sort to be considered on
936 : * the index's partially sorted results.
937 : */
938 1074 : match_pathkeys_to_index(index, root->query_pathkeys,
939 : &orderbyclauses,
940 : &orderbyclausecols);
941 1074 : if (list_length(root->query_pathkeys) == list_length(orderbyclauses))
942 468 : useful_pathkeys = root->query_pathkeys;
943 : else
944 606 : useful_pathkeys = list_copy_head(root->query_pathkeys,
945 : list_length(orderbyclauses));
946 : }
947 : else
948 : {
949 220780 : useful_pathkeys = NIL;
950 220780 : orderbyclauses = NIL;
951 220780 : orderbyclausecols = NIL;
952 : }
953 :
954 : /*
955 : * 3. Check if an index-only scan is possible. If we're not building
956 : * plain indexscans, this isn't relevant since bitmap scans don't support
957 : * index data retrieval anyway.
958 : */
959 1783758 : index_only_scan = (scantype != ST_BITMAPSCAN &&
960 890286 : check_index_only(rel, index));
961 :
962 : /*
963 : * 4. Generate an indexscan path if there are relevant restriction clauses
964 : * in the current clauses, OR the index ordering is potentially useful for
965 : * later merging or final output ordering, OR the index has a useful
966 : * predicate, OR an index-only scan is possible.
967 : */
968 893472 : if (index_clauses != NIL || useful_pathkeys != NIL || useful_predicate ||
969 : index_only_scan)
970 : {
971 539400 : ipath = create_index_path(root, index,
972 : index_clauses,
973 : orderbyclauses,
974 : orderbyclausecols,
975 : useful_pathkeys,
976 : ForwardScanDirection,
977 : index_only_scan,
978 : outer_relids,
979 : loop_count,
980 : false);
981 539400 : result = lappend(result, ipath);
982 :
983 : /*
984 : * If appropriate, consider parallel index scan. We don't allow
985 : * parallel index scan for bitmap index scans.
986 : */
987 539400 : if (index->amcanparallel &&
988 518500 : rel->consider_parallel && outer_relids == NULL &&
989 : scantype != ST_BITMAPSCAN)
990 : {
991 281458 : ipath = create_index_path(root, index,
992 : index_clauses,
993 : orderbyclauses,
994 : orderbyclausecols,
995 : useful_pathkeys,
996 : ForwardScanDirection,
997 : index_only_scan,
998 : outer_relids,
999 : loop_count,
1000 : true);
1001 :
1002 : /*
1003 : * if, after costing the path, we find that it's not worth using
1004 : * parallel workers, just free it.
1005 : */
1006 281458 : if (ipath->path.parallel_workers > 0)
1007 10048 : add_partial_path(rel, (Path *) ipath);
1008 : else
1009 271410 : pfree(ipath);
1010 : }
1011 : }
1012 :
1013 : /*
1014 : * 5. If the index is ordered, a backwards scan might be interesting.
1015 : */
1016 893472 : if (index_is_ordered && pathkeys_possibly_useful)
1017 : {
1018 671618 : index_pathkeys = build_index_pathkeys(root, index,
1019 : BackwardScanDirection);
1020 671618 : useful_pathkeys = truncate_useless_pathkeys(root, rel,
1021 : index_pathkeys);
1022 671618 : if (useful_pathkeys != NIL)
1023 : {
1024 614 : ipath = create_index_path(root, index,
1025 : index_clauses,
1026 : NIL,
1027 : NIL,
1028 : useful_pathkeys,
1029 : BackwardScanDirection,
1030 : index_only_scan,
1031 : outer_relids,
1032 : loop_count,
1033 : false);
1034 614 : result = lappend(result, ipath);
1035 :
1036 : /* If appropriate, consider parallel index scan */
1037 614 : if (index->amcanparallel &&
1038 614 : rel->consider_parallel && outer_relids == NULL &&
1039 : scantype != ST_BITMAPSCAN)
1040 : {
1041 512 : ipath = create_index_path(root, index,
1042 : index_clauses,
1043 : NIL,
1044 : NIL,
1045 : useful_pathkeys,
1046 : BackwardScanDirection,
1047 : index_only_scan,
1048 : outer_relids,
1049 : loop_count,
1050 : true);
1051 :
1052 : /*
1053 : * if, after costing the path, we find that it's not worth
1054 : * using parallel workers, just free it.
1055 : */
1056 512 : if (ipath->path.parallel_workers > 0)
1057 168 : add_partial_path(rel, (Path *) ipath);
1058 : else
1059 344 : pfree(ipath);
1060 : }
1061 : }
1062 : }
1063 :
1064 893472 : return result;
1065 : }
1066 :
1067 : /*
1068 : * build_paths_for_OR
1069 : * Given a list of restriction clauses from one arm of an OR clause,
1070 : * construct all matching IndexPaths for the relation.
1071 : *
1072 : * Here we must scan all indexes of the relation, since a bitmap OR tree
1073 : * can use multiple indexes.
1074 : *
1075 : * The caller actually supplies two lists of restriction clauses: some
1076 : * "current" ones and some "other" ones. Both lists can be used freely
1077 : * to match keys of the index, but an index must use at least one of the
1078 : * "current" clauses to be considered usable. The motivation for this is
1079 : * examples like
1080 : * WHERE (x = 42) AND (... OR (y = 52 AND z = 77) OR ....)
1081 : * While we are considering the y/z subclause of the OR, we can use "x = 42"
1082 : * as one of the available index conditions; but we shouldn't match the
1083 : * subclause to any index on x alone, because such a Path would already have
1084 : * been generated at the upper level. So we could use an index on x,y,z
1085 : * or an index on x,y for the OR subclause, but not an index on just x.
1086 : * When dealing with a partial index, a match of the index predicate to
1087 : * one of the "current" clauses also makes the index usable.
1088 : *
1089 : * 'rel' is the relation for which we want to generate index paths
1090 : * 'clauses' is the current list of clauses (RestrictInfo nodes)
1091 : * 'other_clauses' is the list of additional upper-level clauses
1092 : */
1093 : static List *
1094 10882 : build_paths_for_OR(PlannerInfo *root, RelOptInfo *rel,
1095 : List *clauses, List *other_clauses)
1096 : {
1097 10882 : List *result = NIL;
1098 10882 : List *all_clauses = NIL; /* not computed till needed */
1099 : ListCell *lc;
1100 :
1101 37902 : foreach(lc, rel->indexlist)
1102 : {
1103 27020 : IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
1104 : IndexClauseSet clauseset;
1105 : List *indexpaths;
1106 : bool useful_predicate;
1107 :
1108 : /* Ignore index if it doesn't support bitmap scans */
1109 27020 : if (!index->amhasgetbitmap)
1110 23866 : continue;
1111 :
1112 : /*
1113 : * Ignore partial indexes that do not match the query. If a partial
1114 : * index is marked predOK then we know it's OK. Otherwise, we have to
1115 : * test whether the added clauses are sufficient to imply the
1116 : * predicate. If so, we can use the index in the current context.
1117 : *
1118 : * We set useful_predicate to true iff the predicate was proven using
1119 : * the current set of clauses. This is needed to prevent matching a
1120 : * predOK index to an arm of an OR, which would be a legal but
1121 : * pointlessly inefficient plan. (A better plan will be generated by
1122 : * just scanning the predOK index alone, no OR.)
1123 : */
1124 27020 : useful_predicate = false;
1125 27020 : if (index->indpred != NIL)
1126 : {
1127 168 : if (index->predOK)
1128 : {
1129 : /* Usable, but don't set useful_predicate */
1130 : }
1131 : else
1132 : {
1133 : /* Form all_clauses if not done already */
1134 144 : if (all_clauses == NIL)
1135 60 : all_clauses = list_concat_copy(clauses, other_clauses);
1136 :
1137 144 : if (!predicate_implied_by(index->indpred, all_clauses, false))
1138 96 : continue; /* can't use it at all */
1139 :
1140 48 : if (!predicate_implied_by(index->indpred, other_clauses, false))
1141 48 : useful_predicate = true;
1142 : }
1143 : }
1144 :
1145 : /*
1146 : * Identify the restriction clauses that can match the index.
1147 : */
1148 915416 : MemSet(&clauseset, 0, sizeof(clauseset));
1149 26924 : match_clauses_to_index(root, clauses, index, &clauseset);
1150 :
1151 : /*
1152 : * If no matches so far, and the index predicate isn't useful, we
1153 : * don't want it.
1154 : */
1155 26924 : if (!clauseset.nonempty && !useful_predicate)
1156 23770 : continue;
1157 :
1158 : /*
1159 : * Add "other" restriction clauses to the clauseset.
1160 : */
1161 3154 : match_clauses_to_index(root, other_clauses, index, &clauseset);
1162 :
1163 : /*
1164 : * Construct paths if possible.
1165 : */
1166 3154 : indexpaths = build_index_paths(root, rel,
1167 : index, &clauseset,
1168 : useful_predicate,
1169 : ST_BITMAPSCAN,
1170 : NULL);
1171 3154 : result = list_concat(result, indexpaths);
1172 : }
1173 :
1174 10882 : return result;
1175 : }
1176 :
1177 : /*
1178 : * Utility structure used to group similar OR-clause arguments in
1179 : * group_similar_or_args(). It represents information about the OR-clause
1180 : * argument and its matching index key.
1181 : */
1182 : typedef struct
1183 : {
1184 : int indexnum; /* index of the matching index, or -1 if no
1185 : * matching index */
1186 : int colnum; /* index of the matching column, or -1 if no
1187 : * matching index */
1188 : Oid opno; /* OID of the OpClause operator, or InvalidOid
1189 : * if not an OpExpr */
1190 : Oid inputcollid; /* OID of the OpClause input collation */
1191 : int argindex; /* index of the clause in the list of
1192 : * arguments */
1193 : int groupindex; /* value of argindex for the fist clause in
1194 : * the group of similar clauses */
1195 : } OrArgIndexMatch;
1196 :
1197 : /*
1198 : * Comparison function for OrArgIndexMatch which provides sort order placing
1199 : * similar OR-clause arguments together.
1200 : */
1201 : static int
1202 7150 : or_arg_index_match_cmp(const void *a, const void *b)
1203 : {
1204 7150 : const OrArgIndexMatch *match_a = (const OrArgIndexMatch *) a;
1205 7150 : const OrArgIndexMatch *match_b = (const OrArgIndexMatch *) b;
1206 :
1207 7150 : if (match_a->indexnum < match_b->indexnum)
1208 1358 : return -1;
1209 5792 : else if (match_a->indexnum > match_b->indexnum)
1210 3106 : return 1;
1211 :
1212 2686 : if (match_a->colnum < match_b->colnum)
1213 874 : return -1;
1214 1812 : else if (match_a->colnum > match_b->colnum)
1215 24 : return 1;
1216 :
1217 1788 : if (match_a->opno < match_b->opno)
1218 18 : return -1;
1219 1770 : else if (match_a->opno > match_b->opno)
1220 42 : return 1;
1221 :
1222 1728 : if (match_a->inputcollid < match_b->inputcollid)
1223 0 : return -1;
1224 1728 : else if (match_a->inputcollid > match_b->inputcollid)
1225 0 : return 1;
1226 :
1227 1728 : if (match_a->argindex < match_b->argindex)
1228 1650 : return -1;
1229 78 : else if (match_a->argindex > match_b->argindex)
1230 78 : return 1;
1231 :
1232 0 : return 0;
1233 : }
1234 :
1235 : /*
1236 : * Another comparison function for OrArgIndexMatch. It sorts groups together
1237 : * using groupindex. The group items are then sorted by argindex.
1238 : */
1239 : static int
1240 7240 : or_arg_index_match_cmp_group(const void *a, const void *b)
1241 : {
1242 7240 : const OrArgIndexMatch *match_a = (const OrArgIndexMatch *) a;
1243 7240 : const OrArgIndexMatch *match_b = (const OrArgIndexMatch *) b;
1244 :
1245 7240 : if (match_a->groupindex < match_b->groupindex)
1246 3546 : return -1;
1247 3694 : else if (match_a->groupindex > match_b->groupindex)
1248 3250 : return 1;
1249 :
1250 444 : if (match_a->argindex < match_b->argindex)
1251 444 : return -1;
1252 0 : else if (match_a->argindex > match_b->argindex)
1253 0 : return 1;
1254 :
1255 0 : return 0;
1256 : }
1257 :
1258 : /*
1259 : * group_similar_or_args
1260 : * Transform incoming OR-restrictinfo into a list of sub-restrictinfos,
1261 : * each of them containing a subset of similar OR-clause arguments from
1262 : * the source rinfo.
1263 : *
1264 : * Similar OR-clause arguments are of the form "indexkey op constant" having
1265 : * the same indexkey, operator, and collation. Constant may comprise either
1266 : * Const or Param. It may be employed later, during the
1267 : * match_clause_to_indexcol() to transform the whole OR-sub-rinfo to an SAOP
1268 : * clause.
1269 : *
1270 : * Returns the processed list of OR-clause arguments.
1271 : */
1272 : static List *
1273 9098 : group_similar_or_args(PlannerInfo *root, RelOptInfo *rel, RestrictInfo *rinfo)
1274 : {
1275 : int n;
1276 : int i;
1277 : int group_start;
1278 : OrArgIndexMatch *matches;
1279 9098 : bool matched = false;
1280 : ListCell *lc;
1281 : ListCell *lc2;
1282 : List *orargs;
1283 9098 : List *result = NIL;
1284 9098 : Index relid = rel->relid;
1285 :
1286 : Assert(IsA(rinfo->orclause, BoolExpr));
1287 9098 : orargs = ((BoolExpr *) rinfo->orclause)->args;
1288 9098 : n = list_length(orargs);
1289 :
1290 : /*
1291 : * To avoid N^2 behavior, take utility pass along the list of OR-clause
1292 : * arguments. For each argument, fill the OrArgIndexMatch structure,
1293 : * which will be used to sort these arguments at the next step.
1294 : */
1295 9098 : i = -1;
1296 9098 : matches = palloc_array(OrArgIndexMatch, n);
1297 30640 : foreach(lc, orargs)
1298 : {
1299 21542 : Node *arg = lfirst(lc);
1300 : RestrictInfo *argrinfo;
1301 : OpExpr *clause;
1302 : Oid opno;
1303 : Node *leftop,
1304 : *rightop;
1305 : Node *nonConstExpr;
1306 : int indexnum;
1307 : int colnum;
1308 :
1309 21542 : i++;
1310 21542 : matches[i].argindex = i;
1311 21542 : matches[i].groupindex = i;
1312 21542 : matches[i].indexnum = -1;
1313 21542 : matches[i].colnum = -1;
1314 21542 : matches[i].opno = InvalidOid;
1315 21542 : matches[i].inputcollid = InvalidOid;
1316 :
1317 21542 : if (!IsA(arg, RestrictInfo))
1318 2458 : continue;
1319 :
1320 19084 : argrinfo = castNode(RestrictInfo, arg);
1321 :
1322 : /* Only operator clauses can match */
1323 19084 : if (!IsA(argrinfo->clause, OpExpr))
1324 7798 : continue;
1325 :
1326 11286 : clause = (OpExpr *) argrinfo->clause;
1327 11286 : opno = clause->opno;
1328 :
1329 : /* Only binary operators can match */
1330 11286 : if (list_length(clause->args) != 2)
1331 0 : continue;
1332 :
1333 : /*
1334 : * Ignore any RelabelType node above the operands. This is needed to
1335 : * be able to apply indexscanning in binary-compatible-operator cases.
1336 : * Note: we can assume there is at most one RelabelType node;
1337 : * eval_const_expressions() will have simplified if more than one.
1338 : */
1339 11286 : leftop = get_leftop(clause);
1340 11286 : if (IsA(leftop, RelabelType))
1341 204 : leftop = (Node *) ((RelabelType *) leftop)->arg;
1342 :
1343 11286 : rightop = get_rightop(clause);
1344 11286 : if (IsA(rightop, RelabelType))
1345 808 : rightop = (Node *) ((RelabelType *) rightop)->arg;
1346 :
1347 : /*
1348 : * Check for clauses of the form: (indexkey operator constant) or
1349 : * (constant operator indexkey). But we don't know a particular index
1350 : * yet. Therefore, we try to distinguish the potential index key and
1351 : * constant first, then search for a matching index key among all
1352 : * indexes.
1353 : */
1354 11286 : if (bms_is_member(relid, argrinfo->right_relids) &&
1355 1986 : !bms_is_member(relid, argrinfo->left_relids) &&
1356 1914 : !contain_volatile_functions(leftop))
1357 : {
1358 1914 : opno = get_commutator(opno);
1359 :
1360 1914 : if (!OidIsValid(opno))
1361 : {
1362 : /* commutator doesn't exist, we can't reverse the order */
1363 0 : continue;
1364 : }
1365 1914 : nonConstExpr = rightop;
1366 : }
1367 9372 : else if (bms_is_member(relid, argrinfo->left_relids) &&
1368 7440 : !bms_is_member(relid, argrinfo->right_relids) &&
1369 7368 : !contain_volatile_functions(rightop))
1370 : {
1371 7368 : nonConstExpr = leftop;
1372 : }
1373 : else
1374 : {
1375 2004 : continue;
1376 : }
1377 :
1378 : /*
1379 : * Match non-constant part to the index key. It's possible that a
1380 : * single non-constant part matches multiple index keys. It's OK, we
1381 : * just stop with first matching index key. Given that this choice is
1382 : * determined the same for every clause, we will group similar clauses
1383 : * together anyway.
1384 : */
1385 9282 : indexnum = 0;
1386 20204 : foreach(lc2, rel->indexlist)
1387 : {
1388 16514 : IndexOptInfo *index = (IndexOptInfo *) lfirst(lc2);
1389 :
1390 : /*
1391 : * Ignore index if it doesn't support bitmap scans or SAOP
1392 : * clauses.
1393 : */
1394 16514 : if (!index->amhasgetbitmap || !index->amsearcharray)
1395 54 : continue;
1396 :
1397 37356 : for (colnum = 0; colnum < index->nkeycolumns; colnum++)
1398 : {
1399 26488 : if (match_index_to_operand(nonConstExpr, colnum, index))
1400 : {
1401 5592 : matches[i].indexnum = indexnum;
1402 5592 : matches[i].colnum = colnum;
1403 5592 : matches[i].opno = opno;
1404 5592 : matches[i].inputcollid = clause->inputcollid;
1405 5592 : matched = true;
1406 5592 : break;
1407 : }
1408 : }
1409 :
1410 : /*
1411 : * Stop looping through the indexes, if we managed to match
1412 : * nonConstExpr to any index column.
1413 : */
1414 16460 : if (matches[i].indexnum >= 0)
1415 5592 : break;
1416 10868 : indexnum++;
1417 : }
1418 : }
1419 :
1420 : /*
1421 : * Fast-path check: if no clause is matching to the index column, we can
1422 : * just give up at this stage and return the clause list as-is.
1423 : */
1424 9098 : if (!matched)
1425 : {
1426 5074 : pfree(matches);
1427 5074 : return orargs;
1428 : }
1429 :
1430 : /*
1431 : * Sort clauses to make similar clauses go together. But at the same
1432 : * time, we would like to change the order of clauses as little as
1433 : * possible. To do so, we reorder each group of similar clauses so that
1434 : * the first item of the group stays in place, and all the other items are
1435 : * moved after it. So, if there are no similar clauses, the order of
1436 : * clauses stays the same. When there are some groups, required
1437 : * reordering happens while the rest of the clauses remain in their
1438 : * places. That is achieved by assigning a 'groupindex' to each clause:
1439 : * the number of the first item in the group in the original clause list.
1440 : */
1441 4024 : qsort(matches, n, sizeof(OrArgIndexMatch), or_arg_index_match_cmp);
1442 :
1443 : /* Assign groupindex to the sorted clauses */
1444 9626 : for (i = 1; i < n; i++)
1445 : {
1446 : /*
1447 : * When two clauses are similar and should belong to the same group,
1448 : * copy the 'groupindex' from the previous clause. Given we are
1449 : * considering clauses in direct order, all the clauses would have a
1450 : * 'groupindex' equal to the 'groupindex' of the first clause in the
1451 : * group.
1452 : */
1453 5602 : if (matches[i].indexnum == matches[i - 1].indexnum &&
1454 2566 : matches[i].colnum == matches[i - 1].colnum &&
1455 1680 : matches[i].opno == matches[i - 1].opno &&
1456 1632 : matches[i].inputcollid == matches[i - 1].inputcollid &&
1457 1632 : matches[i].indexnum != -1)
1458 444 : matches[i].groupindex = matches[i - 1].groupindex;
1459 : }
1460 :
1461 : /* Re-sort clauses first by groupindex then by argindex */
1462 4024 : qsort(matches, n, sizeof(OrArgIndexMatch), or_arg_index_match_cmp_group);
1463 :
1464 : /*
1465 : * Group similar clauses into single sub-restrictinfo. Side effect: the
1466 : * resulting list of restrictions will be sorted by indexnum and colnum.
1467 : */
1468 4024 : group_start = 0;
1469 13650 : for (i = 1; i <= n; i++)
1470 : {
1471 : /* Check if it's a group boundary */
1472 9626 : if (group_start >= 0 &&
1473 5602 : (i == n ||
1474 5602 : matches[i].indexnum != matches[group_start].indexnum ||
1475 2494 : matches[i].colnum != matches[group_start].colnum ||
1476 1626 : matches[i].opno != matches[group_start].opno ||
1477 1584 : matches[i].inputcollid != matches[group_start].inputcollid ||
1478 1584 : matches[i].indexnum == -1))
1479 : {
1480 : /*
1481 : * One clause in group: add it "as is" to the upper-level OR.
1482 : */
1483 9182 : if (i - group_start == 1)
1484 : {
1485 8870 : result = lappend(result,
1486 : list_nth(orargs,
1487 8870 : matches[group_start].argindex));
1488 : }
1489 : else
1490 : {
1491 : /*
1492 : * Two or more clauses in a group: create a nested OR.
1493 : */
1494 312 : List *args = NIL;
1495 312 : List *rargs = NIL;
1496 : RestrictInfo *subrinfo;
1497 : int j;
1498 :
1499 : Assert(i - group_start >= 2);
1500 :
1501 : /* Construct the list of nested OR arguments */
1502 1068 : for (j = group_start; j < i; j++)
1503 : {
1504 756 : Node *arg = list_nth(orargs, matches[j].argindex);
1505 :
1506 756 : rargs = lappend(rargs, arg);
1507 756 : if (IsA(arg, RestrictInfo))
1508 756 : args = lappend(args, ((RestrictInfo *) arg)->clause);
1509 : else
1510 0 : args = lappend(args, arg);
1511 : }
1512 :
1513 : /* Construct the nested OR and wrap it with RestrictInfo */
1514 312 : subrinfo = make_plain_restrictinfo(root,
1515 : make_orclause(args),
1516 : make_orclause(rargs),
1517 312 : rinfo->is_pushed_down,
1518 312 : rinfo->has_clone,
1519 312 : rinfo->is_clone,
1520 312 : rinfo->pseudoconstant,
1521 : rinfo->security_level,
1522 : rinfo->required_relids,
1523 : rinfo->incompatible_relids,
1524 : rinfo->outer_relids);
1525 312 : result = lappend(result, subrinfo);
1526 : }
1527 :
1528 9182 : group_start = i;
1529 : }
1530 : }
1531 4024 : pfree(matches);
1532 4024 : return result;
1533 : }
1534 :
1535 : /*
1536 : * make_bitmap_paths_for_or_group
1537 : * Generate bitmap paths for a group of similar OR-clause arguments
1538 : * produced by group_similar_or_args().
1539 : *
1540 : * This function considers two cases: (1) matching a group of clauses to
1541 : * the index as a whole, and (2) matching the individual clauses one-by-one.
1542 : * (1) typically comprises an optimal solution. If not, (2) typically
1543 : * comprises fair alternative.
1544 : *
1545 : * Ideally, we could consider all arbitrary splits of arguments into
1546 : * subgroups, but that could lead to unacceptable computational complexity.
1547 : * This is why we only consider two cases of above.
1548 : */
1549 : static List *
1550 306 : make_bitmap_paths_for_or_group(PlannerInfo *root, RelOptInfo *rel,
1551 : RestrictInfo *ri, List *other_clauses)
1552 : {
1553 306 : List *jointlist = NIL;
1554 306 : List *splitlist = NIL;
1555 : ListCell *lc;
1556 : List *orargs;
1557 306 : List *args = ((BoolExpr *) ri->orclause)->args;
1558 306 : Cost jointcost = 0.0,
1559 306 : splitcost = 0.0;
1560 : Path *bitmapqual;
1561 : List *indlist;
1562 :
1563 : /*
1564 : * First, try to match the whole group to the one index.
1565 : */
1566 306 : orargs = list_make1(ri);
1567 306 : indlist = build_paths_for_OR(root, rel,
1568 : orargs,
1569 : other_clauses);
1570 306 : if (indlist != NIL)
1571 : {
1572 300 : bitmapqual = choose_bitmap_and(root, rel, indlist);
1573 300 : jointcost = bitmapqual->total_cost;
1574 300 : jointlist = list_make1(bitmapqual);
1575 : }
1576 :
1577 : /*
1578 : * If we manage to find a bitmap scan, which uses the group of OR-clause
1579 : * arguments as a whole, we can skip matching OR-clause arguments
1580 : * one-by-one as long as there are no other clauses, which can bring more
1581 : * efficiency to one-by-one case.
1582 : */
1583 306 : if (jointlist != NIL && other_clauses == NIL)
1584 84 : return jointlist;
1585 :
1586 : /*
1587 : * Also try to match all containing clauses one-by-one.
1588 : */
1589 768 : foreach(lc, args)
1590 : {
1591 552 : orargs = list_make1(lfirst(lc));
1592 :
1593 552 : indlist = build_paths_for_OR(root, rel,
1594 : orargs,
1595 : other_clauses);
1596 :
1597 552 : if (indlist == NIL)
1598 : {
1599 6 : splitlist = NIL;
1600 6 : break;
1601 : }
1602 :
1603 546 : bitmapqual = choose_bitmap_and(root, rel, indlist);
1604 546 : splitcost += bitmapqual->total_cost;
1605 546 : splitlist = lappend(splitlist, bitmapqual);
1606 : }
1607 :
1608 : /*
1609 : * Pick the best option.
1610 : */
1611 222 : if (splitlist == NIL)
1612 6 : return jointlist;
1613 216 : else if (jointlist == NIL)
1614 0 : return splitlist;
1615 : else
1616 216 : return (jointcost < splitcost) ? jointlist : splitlist;
1617 : }
1618 :
1619 :
1620 : /*
1621 : * generate_bitmap_or_paths
1622 : * Look through the list of clauses to find OR clauses, and generate
1623 : * a BitmapOrPath for each one we can handle that way. Return a list
1624 : * of the generated BitmapOrPaths.
1625 : *
1626 : * other_clauses is a list of additional clauses that can be assumed true
1627 : * for the purpose of generating indexquals, but are not to be searched for
1628 : * ORs. (See build_paths_for_OR() for motivation.)
1629 : */
1630 : static List *
1631 691148 : generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel,
1632 : List *clauses, List *other_clauses)
1633 : {
1634 691148 : List *result = NIL;
1635 : List *all_clauses;
1636 : ListCell *lc;
1637 :
1638 : /*
1639 : * We can use both the current and other clauses as context for
1640 : * build_paths_for_OR; no need to remove ORs from the lists.
1641 : */
1642 691148 : all_clauses = list_concat_copy(clauses, other_clauses);
1643 :
1644 1071234 : foreach(lc, clauses)
1645 : {
1646 380086 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
1647 : List *pathlist;
1648 : Path *bitmapqual;
1649 : ListCell *j;
1650 : List *groupedArgs;
1651 380086 : List *inner_other_clauses = NIL;
1652 :
1653 : /* Ignore RestrictInfos that aren't ORs */
1654 380086 : if (!restriction_is_or_clause(rinfo))
1655 370988 : continue;
1656 :
1657 : /*
1658 : * We must be able to match at least one index to each of the arms of
1659 : * the OR, else we can't use it.
1660 : */
1661 9098 : pathlist = NIL;
1662 :
1663 : /*
1664 : * Group the similar OR-clause arguments into dedicated RestrictInfos,
1665 : * because each of those RestrictInfos has a chance to match the index
1666 : * as a whole.
1667 : */
1668 9098 : groupedArgs = group_similar_or_args(root, rel, rinfo);
1669 :
1670 9098 : if (groupedArgs != ((BoolExpr *) rinfo->orclause)->args)
1671 : {
1672 : /*
1673 : * Some parts of the rinfo were probably grouped. In this case,
1674 : * we have a set of sub-rinfos that together are an exact
1675 : * duplicate of rinfo. Thus, we need to remove the rinfo from
1676 : * other clauses. match_clauses_to_index detects duplicated
1677 : * iclauses by comparing pointers to original rinfos that would be
1678 : * different. So, we must delete rinfo to avoid de-facto
1679 : * duplicated clauses in the index clauses list.
1680 : */
1681 4024 : inner_other_clauses = list_delete(list_copy(all_clauses), rinfo);
1682 : }
1683 :
1684 11370 : foreach(j, groupedArgs)
1685 : {
1686 10330 : Node *orarg = (Node *) lfirst(j);
1687 : List *indlist;
1688 :
1689 : /* OR arguments should be ANDs or sub-RestrictInfos */
1690 10330 : if (is_andclause(orarg))
1691 : {
1692 1484 : List *andargs = ((BoolExpr *) orarg)->args;
1693 :
1694 1484 : indlist = build_paths_for_OR(root, rel,
1695 : andargs,
1696 : all_clauses);
1697 :
1698 : /* Recurse in case there are sub-ORs */
1699 1484 : indlist = list_concat(indlist,
1700 1484 : generate_bitmap_or_paths(root, rel,
1701 : andargs,
1702 : all_clauses));
1703 : }
1704 8846 : else if (restriction_is_or_clause(castNode(RestrictInfo, orarg)))
1705 : {
1706 306 : RestrictInfo *ri = castNode(RestrictInfo, orarg);
1707 :
1708 : /*
1709 : * Generate bitmap paths for the group of similar OR-clause
1710 : * arguments.
1711 : */
1712 306 : indlist = make_bitmap_paths_for_or_group(root,
1713 : rel, ri,
1714 : inner_other_clauses);
1715 :
1716 306 : if (indlist == NIL)
1717 : {
1718 6 : pathlist = NIL;
1719 6 : break;
1720 : }
1721 : else
1722 : {
1723 300 : pathlist = list_concat(pathlist, indlist);
1724 300 : continue;
1725 : }
1726 : }
1727 : else
1728 : {
1729 8540 : RestrictInfo *ri = castNode(RestrictInfo, orarg);
1730 : List *orargs;
1731 :
1732 8540 : orargs = list_make1(ri);
1733 :
1734 8540 : indlist = build_paths_for_OR(root, rel,
1735 : orargs,
1736 : all_clauses);
1737 : }
1738 :
1739 : /*
1740 : * If nothing matched this arm, we can't do anything with this OR
1741 : * clause.
1742 : */
1743 10024 : if (indlist == NIL)
1744 : {
1745 8052 : pathlist = NIL;
1746 8052 : break;
1747 : }
1748 :
1749 : /*
1750 : * OK, pick the most promising AND combination, and add it to
1751 : * pathlist.
1752 : */
1753 1972 : bitmapqual = choose_bitmap_and(root, rel, indlist);
1754 1972 : pathlist = lappend(pathlist, bitmapqual);
1755 : }
1756 :
1757 9098 : if (inner_other_clauses != NIL)
1758 2242 : list_free(inner_other_clauses);
1759 :
1760 : /*
1761 : * If we have a match for every arm, then turn them into a
1762 : * BitmapOrPath, and add to result list.
1763 : */
1764 9098 : if (pathlist != NIL)
1765 : {
1766 1040 : bitmapqual = (Path *) create_bitmap_or_path(root, rel, pathlist);
1767 1040 : result = lappend(result, bitmapqual);
1768 : }
1769 : }
1770 :
1771 691148 : return result;
1772 : }
1773 :
1774 :
1775 : /*
1776 : * choose_bitmap_and
1777 : * Given a nonempty list of bitmap paths, AND them into one path.
1778 : *
1779 : * This is a nontrivial decision since we can legally use any subset of the
1780 : * given path set. We want to choose a good tradeoff between selectivity
1781 : * and cost of computing the bitmap.
1782 : *
1783 : * The result is either a single one of the inputs, or a BitmapAndPath
1784 : * combining multiple inputs.
1785 : */
1786 : static Path *
1787 360968 : choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel, List *paths)
1788 : {
1789 360968 : int npaths = list_length(paths);
1790 : PathClauseUsage **pathinfoarray;
1791 : PathClauseUsage *pathinfo;
1792 : List *clauselist;
1793 360968 : List *bestpaths = NIL;
1794 360968 : Cost bestcost = 0;
1795 : int i,
1796 : j;
1797 : ListCell *l;
1798 :
1799 : Assert(npaths > 0); /* else caller error */
1800 360968 : if (npaths == 1)
1801 280724 : return (Path *) linitial(paths); /* easy case */
1802 :
1803 : /*
1804 : * In theory we should consider every nonempty subset of the given paths.
1805 : * In practice that seems like overkill, given the crude nature of the
1806 : * estimates, not to mention the possible effects of higher-level AND and
1807 : * OR clauses. Moreover, it's completely impractical if there are a large
1808 : * number of paths, since the work would grow as O(2^N).
1809 : *
1810 : * As a heuristic, we first check for paths using exactly the same sets of
1811 : * WHERE clauses + index predicate conditions, and reject all but the
1812 : * cheapest-to-scan in any such group. This primarily gets rid of indexes
1813 : * that include the interesting columns but also irrelevant columns. (In
1814 : * situations where the DBA has gone overboard on creating variant
1815 : * indexes, this can make for a very large reduction in the number of
1816 : * paths considered further.)
1817 : *
1818 : * We then sort the surviving paths with the cheapest-to-scan first, and
1819 : * for each path, consider using that path alone as the basis for a bitmap
1820 : * scan. Then we consider bitmap AND scans formed from that path plus
1821 : * each subsequent (higher-cost) path, adding on a subsequent path if it
1822 : * results in a reduction in the estimated total scan cost. This means we
1823 : * consider about O(N^2) rather than O(2^N) path combinations, which is
1824 : * quite tolerable, especially given than N is usually reasonably small
1825 : * because of the prefiltering step. The cheapest of these is returned.
1826 : *
1827 : * We will only consider AND combinations in which no two indexes use the
1828 : * same WHERE clause. This is a bit of a kluge: it's needed because
1829 : * costsize.c and clausesel.c aren't very smart about redundant clauses.
1830 : * They will usually double-count the redundant clauses, producing a
1831 : * too-small selectivity that makes a redundant AND step look like it
1832 : * reduces the total cost. Perhaps someday that code will be smarter and
1833 : * we can remove this limitation. (But note that this also defends
1834 : * against flat-out duplicate input paths, which can happen because
1835 : * match_join_clauses_to_index will find the same OR join clauses that
1836 : * extract_restriction_or_clauses has pulled OR restriction clauses out
1837 : * of.)
1838 : *
1839 : * For the same reason, we reject AND combinations in which an index
1840 : * predicate clause duplicates another clause. Here we find it necessary
1841 : * to be even stricter: we'll reject a partial index if any of its
1842 : * predicate clauses are implied by the set of WHERE clauses and predicate
1843 : * clauses used so far. This covers cases such as a condition "x = 42"
1844 : * used with a plain index, followed by a clauseless scan of a partial
1845 : * index "WHERE x >= 40 AND x < 50". The partial index has been accepted
1846 : * only because "x = 42" was present, and so allowing it would partially
1847 : * double-count selectivity. (We could use predicate_implied_by on
1848 : * regular qual clauses too, to have a more intelligent, but much more
1849 : * expensive, check for redundancy --- but in most cases simple equality
1850 : * seems to suffice.)
1851 : */
1852 :
1853 : /*
1854 : * Extract clause usage info and detect any paths that use exactly the
1855 : * same set of clauses; keep only the cheapest-to-scan of any such groups.
1856 : * The surviving paths are put into an array for qsort'ing.
1857 : */
1858 80244 : pathinfoarray = palloc_array(PathClauseUsage *, npaths);
1859 80244 : clauselist = NIL;
1860 80244 : npaths = 0;
1861 263976 : foreach(l, paths)
1862 : {
1863 183732 : Path *ipath = (Path *) lfirst(l);
1864 :
1865 183732 : pathinfo = classify_index_clause_usage(ipath, &clauselist);
1866 :
1867 : /* If it's unclassifiable, treat it as distinct from all others */
1868 183732 : if (pathinfo->unclassifiable)
1869 : {
1870 0 : pathinfoarray[npaths++] = pathinfo;
1871 0 : continue;
1872 : }
1873 :
1874 286912 : for (i = 0; i < npaths; i++)
1875 : {
1876 253284 : if (!pathinfoarray[i]->unclassifiable &&
1877 126642 : bms_equal(pathinfo->clauseids, pathinfoarray[i]->clauseids))
1878 23462 : break;
1879 : }
1880 183732 : if (i < npaths)
1881 : {
1882 : /* duplicate clauseids, keep the cheaper one */
1883 : Cost ncost;
1884 : Cost ocost;
1885 : Selectivity nselec;
1886 : Selectivity oselec;
1887 :
1888 23462 : cost_bitmap_tree_node(pathinfo->path, &ncost, &nselec);
1889 23462 : cost_bitmap_tree_node(pathinfoarray[i]->path, &ocost, &oselec);
1890 23462 : if (ncost < ocost)
1891 5170 : pathinfoarray[i] = pathinfo;
1892 : }
1893 : else
1894 : {
1895 : /* not duplicate clauseids, add to array */
1896 160270 : pathinfoarray[npaths++] = pathinfo;
1897 : }
1898 : }
1899 :
1900 : /* If only one surviving path, we're done */
1901 80244 : if (npaths == 1)
1902 14678 : return pathinfoarray[0]->path;
1903 :
1904 : /* Sort the surviving paths by index access cost */
1905 65566 : qsort(pathinfoarray, npaths, sizeof(PathClauseUsage *),
1906 : path_usage_comparator);
1907 :
1908 : /*
1909 : * For each surviving index, consider it as an "AND group leader", and see
1910 : * whether adding on any of the later indexes results in an AND path with
1911 : * cheaper total cost than before. Then take the cheapest AND group.
1912 : *
1913 : * Note: paths that are either clauseless or unclassifiable will have
1914 : * empty clauseids, so that they will not be rejected by the clauseids
1915 : * filter here, nor will they cause later paths to be rejected by it.
1916 : */
1917 211158 : for (i = 0; i < npaths; i++)
1918 : {
1919 : Cost costsofar;
1920 : List *qualsofar;
1921 : Bitmapset *clauseidsofar;
1922 :
1923 145592 : pathinfo = pathinfoarray[i];
1924 145592 : paths = list_make1(pathinfo->path);
1925 145592 : costsofar = bitmap_scan_cost_est(root, rel, pathinfo->path);
1926 145592 : qualsofar = list_concat_copy(pathinfo->quals, pathinfo->preds);
1927 145592 : clauseidsofar = bms_copy(pathinfo->clauseids);
1928 :
1929 240516 : for (j = i + 1; j < npaths; j++)
1930 : {
1931 : Cost newcost;
1932 :
1933 94924 : pathinfo = pathinfoarray[j];
1934 : /* Check for redundancy */
1935 94924 : if (bms_overlap(pathinfo->clauseids, clauseidsofar))
1936 44604 : continue; /* consider it redundant */
1937 50320 : if (pathinfo->preds)
1938 : {
1939 24 : bool redundant = false;
1940 :
1941 : /* we check each predicate clause separately */
1942 24 : foreach(l, pathinfo->preds)
1943 : {
1944 24 : Node *np = (Node *) lfirst(l);
1945 :
1946 24 : if (predicate_implied_by(list_make1(np), qualsofar, false))
1947 : {
1948 24 : redundant = true;
1949 24 : break; /* out of inner foreach loop */
1950 : }
1951 : }
1952 24 : if (redundant)
1953 24 : continue;
1954 : }
1955 : /* tentatively add new path to paths, so we can estimate cost */
1956 50296 : paths = lappend(paths, pathinfo->path);
1957 50296 : newcost = bitmap_and_cost_est(root, rel, paths);
1958 50296 : if (newcost < costsofar)
1959 : {
1960 : /* keep new path in paths, update subsidiary variables */
1961 292 : costsofar = newcost;
1962 292 : qualsofar = list_concat(qualsofar, pathinfo->quals);
1963 292 : qualsofar = list_concat(qualsofar, pathinfo->preds);
1964 292 : clauseidsofar = bms_add_members(clauseidsofar,
1965 292 : pathinfo->clauseids);
1966 : }
1967 : else
1968 : {
1969 : /* reject new path, remove it from paths list */
1970 50004 : paths = list_truncate(paths, list_length(paths) - 1);
1971 : }
1972 : }
1973 :
1974 : /* Keep the cheapest AND-group (or singleton) */
1975 145592 : if (i == 0 || costsofar < bestcost)
1976 : {
1977 70564 : bestpaths = paths;
1978 70564 : bestcost = costsofar;
1979 : }
1980 :
1981 : /* some easy cleanup (we don't try real hard though) */
1982 145592 : list_free(qualsofar);
1983 : }
1984 :
1985 65566 : if (list_length(bestpaths) == 1)
1986 65298 : return (Path *) linitial(bestpaths); /* no need for AND */
1987 268 : return (Path *) create_bitmap_and_path(root, rel, bestpaths);
1988 : }
1989 :
1990 : /* qsort comparator to sort in increasing index access cost order */
1991 : static int
1992 86884 : path_usage_comparator(const void *a, const void *b)
1993 : {
1994 86884 : PathClauseUsage *pa = *(PathClauseUsage *const *) a;
1995 86884 : PathClauseUsage *pb = *(PathClauseUsage *const *) b;
1996 : Cost acost;
1997 : Cost bcost;
1998 : Selectivity aselec;
1999 : Selectivity bselec;
2000 :
2001 86884 : cost_bitmap_tree_node(pa->path, &acost, &aselec);
2002 86884 : cost_bitmap_tree_node(pb->path, &bcost, &bselec);
2003 :
2004 : /*
2005 : * If costs are the same, sort by selectivity.
2006 : */
2007 86884 : if (acost < bcost)
2008 57260 : return -1;
2009 29624 : if (acost > bcost)
2010 19198 : return 1;
2011 :
2012 10426 : if (aselec < bselec)
2013 5498 : return -1;
2014 4928 : if (aselec > bselec)
2015 1164 : return 1;
2016 :
2017 3764 : return 0;
2018 : }
2019 :
2020 : /*
2021 : * Estimate the cost of actually executing a bitmap scan with a single
2022 : * index path (which could be a BitmapAnd or BitmapOr node).
2023 : */
2024 : static Cost
2025 195888 : bitmap_scan_cost_est(PlannerInfo *root, RelOptInfo *rel, Path *ipath)
2026 : {
2027 : BitmapHeapPath bpath;
2028 :
2029 : /* Set up a dummy BitmapHeapPath */
2030 195888 : bpath.path.type = T_BitmapHeapPath;
2031 195888 : bpath.path.pathtype = T_BitmapHeapScan;
2032 195888 : bpath.path.parent = rel;
2033 195888 : bpath.path.pathtarget = rel->reltarget;
2034 195888 : bpath.path.param_info = ipath->param_info;
2035 195888 : bpath.path.pathkeys = NIL;
2036 195888 : bpath.bitmapqual = ipath;
2037 :
2038 : /*
2039 : * Check the cost of temporary path without considering parallelism.
2040 : * Parallel bitmap heap path will be considered at later stage.
2041 : */
2042 195888 : bpath.path.parallel_workers = 0;
2043 :
2044 : /* Now we can do cost_bitmap_heap_scan */
2045 195888 : cost_bitmap_heap_scan(&bpath.path, root, rel,
2046 : bpath.path.param_info,
2047 : ipath,
2048 : get_loop_count(root, rel->relid,
2049 195888 : PATH_REQ_OUTER(ipath)));
2050 :
2051 195888 : return bpath.path.total_cost;
2052 : }
2053 :
2054 : /*
2055 : * Estimate the cost of actually executing a BitmapAnd scan with the given
2056 : * inputs.
2057 : */
2058 : static Cost
2059 50296 : bitmap_and_cost_est(PlannerInfo *root, RelOptInfo *rel, List *paths)
2060 : {
2061 : BitmapAndPath *apath;
2062 :
2063 : /*
2064 : * Might as well build a real BitmapAndPath here, as the work is slightly
2065 : * too complicated to be worth repeating just to save one palloc.
2066 : */
2067 50296 : apath = create_bitmap_and_path(root, rel, paths);
2068 :
2069 50296 : return bitmap_scan_cost_est(root, rel, (Path *) apath);
2070 : }
2071 :
2072 :
2073 : /*
2074 : * classify_index_clause_usage
2075 : * Construct a PathClauseUsage struct describing the WHERE clauses and
2076 : * index predicate clauses used by the given indexscan path.
2077 : * We consider two clauses the same if they are equal().
2078 : *
2079 : * At some point we might want to migrate this info into the Path data
2080 : * structure proper, but for the moment it's only needed within
2081 : * choose_bitmap_and().
2082 : *
2083 : * *clauselist is used and expanded as needed to identify all the distinct
2084 : * clauses seen across successive calls. Caller must initialize it to NIL
2085 : * before first call of a set.
2086 : */
2087 : static PathClauseUsage *
2088 183732 : classify_index_clause_usage(Path *path, List **clauselist)
2089 : {
2090 : PathClauseUsage *result;
2091 : Bitmapset *clauseids;
2092 : ListCell *lc;
2093 :
2094 183732 : result = palloc_object(PathClauseUsage);
2095 183732 : result->path = path;
2096 :
2097 : /* Recursively find the quals and preds used by the path */
2098 183732 : result->quals = NIL;
2099 183732 : result->preds = NIL;
2100 183732 : find_indexpath_quals(path, &result->quals, &result->preds);
2101 :
2102 : /*
2103 : * Some machine-generated queries have outlandish numbers of qual clauses.
2104 : * To avoid getting into O(N^2) behavior even in this preliminary
2105 : * classification step, we want to limit the number of entries we can
2106 : * accumulate in *clauselist. Treat any path with more than 100 quals +
2107 : * preds as unclassifiable, which will cause calling code to consider it
2108 : * distinct from all other paths.
2109 : */
2110 183732 : if (list_length(result->quals) + list_length(result->preds) > 100)
2111 : {
2112 0 : result->clauseids = NULL;
2113 0 : result->unclassifiable = true;
2114 0 : return result;
2115 : }
2116 :
2117 : /* Build up a bitmapset representing the quals and preds */
2118 183732 : clauseids = NULL;
2119 424734 : foreach(lc, result->quals)
2120 : {
2121 241002 : Node *node = (Node *) lfirst(lc);
2122 :
2123 241002 : clauseids = bms_add_member(clauseids,
2124 : find_list_position(node, clauselist));
2125 : }
2126 184020 : foreach(lc, result->preds)
2127 : {
2128 288 : Node *node = (Node *) lfirst(lc);
2129 :
2130 288 : clauseids = bms_add_member(clauseids,
2131 : find_list_position(node, clauselist));
2132 : }
2133 183732 : result->clauseids = clauseids;
2134 183732 : result->unclassifiable = false;
2135 :
2136 183732 : return result;
2137 : }
2138 :
2139 :
2140 : /*
2141 : * find_indexpath_quals
2142 : *
2143 : * Given the Path structure for a plain or bitmap indexscan, extract lists
2144 : * of all the index clauses and index predicate conditions used in the Path.
2145 : * These are appended to the initial contents of *quals and *preds (hence
2146 : * caller should initialize those to NIL).
2147 : *
2148 : * Note we are not trying to produce an accurate representation of the AND/OR
2149 : * semantics of the Path, but just find out all the base conditions used.
2150 : *
2151 : * The result lists contain pointers to the expressions used in the Path,
2152 : * but all the list cells are freshly built, so it's safe to destructively
2153 : * modify the lists (eg, by concat'ing with other lists).
2154 : */
2155 : static void
2156 186142 : find_indexpath_quals(Path *bitmapqual, List **quals, List **preds)
2157 : {
2158 186142 : if (IsA(bitmapqual, BitmapAndPath))
2159 : {
2160 0 : BitmapAndPath *apath = (BitmapAndPath *) bitmapqual;
2161 : ListCell *l;
2162 :
2163 0 : foreach(l, apath->bitmapquals)
2164 : {
2165 0 : find_indexpath_quals((Path *) lfirst(l), quals, preds);
2166 : }
2167 : }
2168 186142 : else if (IsA(bitmapqual, BitmapOrPath))
2169 : {
2170 1310 : BitmapOrPath *opath = (BitmapOrPath *) bitmapqual;
2171 : ListCell *l;
2172 :
2173 3720 : foreach(l, opath->bitmapquals)
2174 : {
2175 2410 : find_indexpath_quals((Path *) lfirst(l), quals, preds);
2176 : }
2177 : }
2178 184832 : else if (IsA(bitmapqual, IndexPath))
2179 : {
2180 184832 : IndexPath *ipath = (IndexPath *) bitmapqual;
2181 : ListCell *l;
2182 :
2183 425834 : foreach(l, ipath->indexclauses)
2184 : {
2185 241002 : IndexClause *iclause = (IndexClause *) lfirst(l);
2186 :
2187 241002 : *quals = lappend(*quals, iclause->rinfo->clause);
2188 : }
2189 184832 : *preds = list_concat(*preds, ipath->indexinfo->indpred);
2190 : }
2191 : else
2192 0 : elog(ERROR, "unrecognized node type: %d", nodeTag(bitmapqual));
2193 186142 : }
2194 :
2195 :
2196 : /*
2197 : * find_list_position
2198 : * Return the given node's position (counting from 0) in the given
2199 : * list of nodes. If it's not equal() to any existing list member,
2200 : * add it at the end, and return that position.
2201 : */
2202 : static int
2203 241290 : find_list_position(Node *node, List **nodelist)
2204 : {
2205 : int i;
2206 : ListCell *lc;
2207 :
2208 241290 : i = 0;
2209 388086 : foreach(lc, *nodelist)
2210 : {
2211 218120 : Node *oldnode = (Node *) lfirst(lc);
2212 :
2213 218120 : if (equal(node, oldnode))
2214 71324 : return i;
2215 146796 : i++;
2216 : }
2217 :
2218 169966 : *nodelist = lappend(*nodelist, node);
2219 :
2220 169966 : return i;
2221 : }
2222 :
2223 :
2224 : /*
2225 : * check_index_only
2226 : * Determine whether an index-only scan is possible for this index.
2227 : */
2228 : static bool
2229 890286 : check_index_only(RelOptInfo *rel, IndexOptInfo *index)
2230 : {
2231 : bool result;
2232 890286 : Bitmapset *attrs_used = NULL;
2233 890286 : Bitmapset *index_canreturn_attrs = NULL;
2234 : ListCell *lc;
2235 : int i;
2236 :
2237 : /* Index-only scans must be enabled */
2238 890286 : if (!enable_indexonlyscan)
2239 3858 : return false;
2240 :
2241 : /*
2242 : * Check that all needed attributes of the relation are available from the
2243 : * index.
2244 : */
2245 :
2246 : /*
2247 : * First, identify all the attributes needed for joins or final output.
2248 : * Note: we must look at rel's targetlist, not the attr_needed data,
2249 : * because attr_needed isn't computed for inheritance child rels.
2250 : */
2251 886428 : pull_varattnos((Node *) rel->reltarget->exprs, rel->relid, &attrs_used);
2252 :
2253 : /*
2254 : * Add all the attributes used by restriction clauses; but consider only
2255 : * those clauses not implied by the index predicate, since ones that are
2256 : * so implied don't need to be checked explicitly in the plan.
2257 : *
2258 : * Note: attributes used only in index quals would not be needed at
2259 : * runtime either, if we are certain that the index is not lossy. However
2260 : * it'd be complicated to account for that accurately, and it doesn't
2261 : * matter in most cases, since we'd conclude that such attributes are
2262 : * available from the index anyway.
2263 : */
2264 1824922 : foreach(lc, index->indrestrictinfo)
2265 : {
2266 938494 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
2267 :
2268 938494 : pull_varattnos((Node *) rinfo->clause, rel->relid, &attrs_used);
2269 : }
2270 :
2271 : /*
2272 : * Construct a bitmapset of columns that the index can return back in an
2273 : * index-only scan.
2274 : */
2275 2517684 : for (i = 0; i < index->ncolumns; i++)
2276 : {
2277 1631256 : int attno = index->indexkeys[i];
2278 :
2279 : /*
2280 : * For the moment, we just ignore index expressions. It might be nice
2281 : * to do something with them, later.
2282 : */
2283 1631256 : if (attno == 0)
2284 3310 : continue;
2285 :
2286 1627946 : if (index->canreturn[i])
2287 : index_canreturn_attrs =
2288 1352398 : bms_add_member(index_canreturn_attrs,
2289 : attno - FirstLowInvalidHeapAttributeNumber);
2290 : }
2291 :
2292 : /* Do we have all the necessary attributes? */
2293 886428 : result = bms_is_subset(attrs_used, index_canreturn_attrs);
2294 :
2295 886428 : bms_free(attrs_used);
2296 886428 : bms_free(index_canreturn_attrs);
2297 :
2298 886428 : return result;
2299 : }
2300 :
2301 : /*
2302 : * get_loop_count
2303 : * Choose the loop count estimate to use for costing a parameterized path
2304 : * with the given set of outer relids.
2305 : *
2306 : * Since we produce parameterized paths before we've begun to generate join
2307 : * relations, it's impossible to predict exactly how many times a parameterized
2308 : * path will be iterated; we don't know the size of the relation that will be
2309 : * on the outside of the nestloop. However, we should try to account for
2310 : * multiple iterations somehow in costing the path. The heuristic embodied
2311 : * here is to use the rowcount of the smallest other base relation needed in
2312 : * the join clauses used by the path. (We could alternatively consider the
2313 : * largest one, but that seems too optimistic.) This is of course the right
2314 : * answer for single-other-relation cases, and it seems like a reasonable
2315 : * zero-order approximation for multiway-join cases.
2316 : *
2317 : * In addition, we check to see if the other side of each join clause is on
2318 : * the inside of some semijoin that the current relation is on the outside of.
2319 : * If so, the only way that a parameterized path could be used is if the
2320 : * semijoin RHS has been unique-ified, so we should use the number of unique
2321 : * RHS rows rather than using the relation's raw rowcount.
2322 : *
2323 : * Note: for this to work, allpaths.c must establish all baserel size
2324 : * estimates before it begins to compute paths, or at least before it
2325 : * calls create_index_paths().
2326 : */
2327 : static double
2328 1238906 : get_loop_count(PlannerInfo *root, Index cur_relid, Relids outer_relids)
2329 : {
2330 : double result;
2331 : int outer_relid;
2332 :
2333 : /* For a non-parameterized path, just return 1.0 quickly */
2334 1238906 : if (outer_relids == NULL)
2335 844742 : return 1.0;
2336 :
2337 394164 : result = 0.0;
2338 394164 : outer_relid = -1;
2339 799504 : while ((outer_relid = bms_next_member(outer_relids, outer_relid)) >= 0)
2340 : {
2341 : RelOptInfo *outer_rel;
2342 : double rowcount;
2343 :
2344 : /* Paranoia: ignore bogus relid indexes */
2345 405340 : if (outer_relid >= root->simple_rel_array_size)
2346 0 : continue;
2347 405340 : outer_rel = root->simple_rel_array[outer_relid];
2348 405340 : if (outer_rel == NULL)
2349 254 : continue;
2350 : Assert(outer_rel->relid == outer_relid); /* sanity check on array */
2351 :
2352 : /* Other relation could be proven empty, if so ignore */
2353 405086 : if (IS_DUMMY_REL(outer_rel))
2354 24 : continue;
2355 :
2356 : /* Otherwise, rel's rows estimate should be valid by now */
2357 : Assert(outer_rel->rows > 0);
2358 :
2359 : /* Check to see if rel is on the inside of any semijoins */
2360 405062 : rowcount = adjust_rowcount_for_semijoins(root,
2361 : cur_relid,
2362 : outer_relid,
2363 : outer_rel->rows);
2364 :
2365 : /* Remember smallest row count estimate among the outer rels */
2366 405062 : if (result == 0.0 || result > rowcount)
2367 401372 : result = rowcount;
2368 : }
2369 : /* Return 1.0 if we found no valid relations (shouldn't happen) */
2370 394164 : return (result > 0.0) ? result : 1.0;
2371 : }
2372 :
2373 : /*
2374 : * Check to see if outer_relid is on the inside of any semijoin that cur_relid
2375 : * is on the outside of. If so, replace rowcount with the estimated number of
2376 : * unique rows from the semijoin RHS (assuming that's smaller, which it might
2377 : * not be). The estimate is crude but it's the best we can do at this stage
2378 : * of the proceedings.
2379 : */
2380 : static double
2381 405062 : adjust_rowcount_for_semijoins(PlannerInfo *root,
2382 : Index cur_relid,
2383 : Index outer_relid,
2384 : double rowcount)
2385 : {
2386 : ListCell *lc;
2387 :
2388 628520 : foreach(lc, root->join_info_list)
2389 : {
2390 223458 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(lc);
2391 :
2392 231806 : if (sjinfo->jointype == JOIN_SEMI &&
2393 12074 : bms_is_member(cur_relid, sjinfo->syn_lefthand) &&
2394 3726 : bms_is_member(outer_relid, sjinfo->syn_righthand))
2395 : {
2396 : /* Estimate number of unique-ified rows */
2397 : double nraw;
2398 : double nunique;
2399 :
2400 1360 : nraw = approximate_joinrel_size(root, sjinfo->syn_righthand);
2401 1360 : nunique = estimate_num_groups(root,
2402 : sjinfo->semi_rhs_exprs,
2403 : nraw,
2404 : NULL,
2405 : NULL);
2406 1360 : if (rowcount > nunique)
2407 470 : rowcount = nunique;
2408 : }
2409 : }
2410 405062 : return rowcount;
2411 : }
2412 :
2413 : /*
2414 : * Make an approximate estimate of the size of a joinrel.
2415 : *
2416 : * We don't have enough info at this point to get a good estimate, so we
2417 : * just multiply the base relation sizes together. Fortunately, this is
2418 : * the right answer anyway for the most common case with a single relation
2419 : * on the RHS of a semijoin. Also, estimate_num_groups() has only a weak
2420 : * dependency on its input_rows argument (it basically uses it as a clamp).
2421 : * So we might be able to get a fairly decent end result even with a severe
2422 : * overestimate of the RHS's raw size.
2423 : */
2424 : static double
2425 1360 : approximate_joinrel_size(PlannerInfo *root, Relids relids)
2426 : {
2427 1360 : double rowcount = 1.0;
2428 : int relid;
2429 :
2430 1360 : relid = -1;
2431 2924 : while ((relid = bms_next_member(relids, relid)) >= 0)
2432 : {
2433 : RelOptInfo *rel;
2434 :
2435 : /* Paranoia: ignore bogus relid indexes */
2436 1564 : if (relid >= root->simple_rel_array_size)
2437 0 : continue;
2438 1564 : rel = root->simple_rel_array[relid];
2439 1564 : if (rel == NULL)
2440 0 : continue;
2441 : Assert(rel->relid == relid); /* sanity check on array */
2442 :
2443 : /* Relation could be proven empty, if so ignore */
2444 1564 : if (IS_DUMMY_REL(rel))
2445 0 : continue;
2446 :
2447 : /* Otherwise, rel's rows estimate should be valid by now */
2448 : Assert(rel->rows > 0);
2449 :
2450 : /* Accumulate product */
2451 1564 : rowcount *= rel->rows;
2452 : }
2453 1360 : return rowcount;
2454 : }
2455 :
2456 :
2457 : /****************************************************************************
2458 : * ---- ROUTINES TO CHECK QUERY CLAUSES ----
2459 : ****************************************************************************/
2460 :
2461 : /*
2462 : * match_restriction_clauses_to_index
2463 : * Identify restriction clauses for the rel that match the index.
2464 : * Matching clauses are added to *clauseset.
2465 : */
2466 : static void
2467 733782 : match_restriction_clauses_to_index(PlannerInfo *root,
2468 : IndexOptInfo *index,
2469 : IndexClauseSet *clauseset)
2470 : {
2471 : /* We can ignore clauses that are implied by the index predicate */
2472 733782 : match_clauses_to_index(root, index->indrestrictinfo, index, clauseset);
2473 733782 : }
2474 :
2475 : /*
2476 : * match_join_clauses_to_index
2477 : * Identify join clauses for the rel that match the index.
2478 : * Matching clauses are added to *clauseset.
2479 : * Also, add any potentially usable join OR clauses to *joinorclauses.
2480 : * They also might be processed by match_clause_to_index() as a whole.
2481 : */
2482 : static void
2483 733782 : match_join_clauses_to_index(PlannerInfo *root,
2484 : RelOptInfo *rel, IndexOptInfo *index,
2485 : IndexClauseSet *clauseset,
2486 : List **joinorclauses)
2487 : {
2488 : ListCell *lc;
2489 :
2490 : /* Scan the rel's join clauses */
2491 987818 : foreach(lc, rel->joininfo)
2492 : {
2493 254036 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
2494 :
2495 : /* Check if clause can be moved to this rel */
2496 254036 : if (!join_clause_is_movable_to(rinfo, rel))
2497 155288 : continue;
2498 :
2499 : /*
2500 : * Potentially usable, so see if it matches the index or is an OR. Use
2501 : * list_append_unique_ptr() here to avoid possible duplicates when
2502 : * processing the same clauses with different indexes.
2503 : */
2504 98748 : if (restriction_is_or_clause(rinfo))
2505 13402 : *joinorclauses = list_append_unique_ptr(*joinorclauses, rinfo);
2506 :
2507 98748 : match_clause_to_index(root, rinfo, index, clauseset);
2508 : }
2509 733782 : }
2510 :
2511 : /*
2512 : * match_eclass_clauses_to_index
2513 : * Identify EquivalenceClass join clauses for the rel that match the index.
2514 : * Matching clauses are added to *clauseset.
2515 : */
2516 : static void
2517 733782 : match_eclass_clauses_to_index(PlannerInfo *root, IndexOptInfo *index,
2518 : IndexClauseSet *clauseset)
2519 : {
2520 : int indexcol;
2521 :
2522 : /* No work if rel is not in any such ECs */
2523 733782 : if (!index->rel->has_eclass_joins)
2524 421640 : return;
2525 :
2526 820350 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
2527 : {
2528 : ec_member_matches_arg arg;
2529 : List *clauses;
2530 :
2531 : /* Generate clauses, skipping any that join to lateral_referencers */
2532 508208 : arg.index = index;
2533 508208 : arg.indexcol = indexcol;
2534 508208 : clauses = generate_implied_equalities_for_column(root,
2535 : index->rel,
2536 : ec_member_matches_indexcol,
2537 : &arg,
2538 508208 : index->rel->lateral_referencers);
2539 :
2540 : /*
2541 : * We have to check whether the results actually do match the index,
2542 : * since for non-btree indexes the EC's equality operators might not
2543 : * be in the index opclass (cf ec_member_matches_indexcol).
2544 : */
2545 508208 : match_clauses_to_index(root, clauses, index, clauseset);
2546 : }
2547 : }
2548 :
2549 : /*
2550 : * match_clauses_to_index
2551 : * Perform match_clause_to_index() for each clause in a list.
2552 : * Matching clauses are added to *clauseset.
2553 : */
2554 : static void
2555 1272068 : match_clauses_to_index(PlannerInfo *root,
2556 : List *clauses,
2557 : IndexOptInfo *index,
2558 : IndexClauseSet *clauseset)
2559 : {
2560 : ListCell *lc;
2561 :
2562 2282668 : foreach(lc, clauses)
2563 : {
2564 1010600 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
2565 :
2566 1010600 : match_clause_to_index(root, rinfo, index, clauseset);
2567 : }
2568 1272068 : }
2569 :
2570 : /*
2571 : * match_clause_to_index
2572 : * Test whether a qual clause can be used with an index.
2573 : *
2574 : * If the clause is usable, add an IndexClause entry for it to the appropriate
2575 : * list in *clauseset. (*clauseset must be initialized to zeroes before first
2576 : * call.)
2577 : *
2578 : * Note: in some circumstances we may find the same RestrictInfos coming from
2579 : * multiple places. Defend against redundant outputs by refusing to add a
2580 : * clause twice (pointer equality should be a good enough check for this).
2581 : *
2582 : * Note: it's possible that a badly-defined index could have multiple matching
2583 : * columns. We always select the first match if so; this avoids scenarios
2584 : * wherein we get an inflated idea of the index's selectivity by using the
2585 : * same clause multiple times with different index columns.
2586 : */
2587 : static void
2588 1109348 : match_clause_to_index(PlannerInfo *root,
2589 : RestrictInfo *rinfo,
2590 : IndexOptInfo *index,
2591 : IndexClauseSet *clauseset)
2592 : {
2593 : int indexcol;
2594 :
2595 : /*
2596 : * Never match pseudoconstants to indexes. (Normally a match could not
2597 : * happen anyway, since a pseudoconstant clause couldn't contain a Var,
2598 : * but what if someone builds an expression index on a constant? It's not
2599 : * totally unreasonable to do so with a partial index, either.)
2600 : */
2601 1109348 : if (rinfo->pseudoconstant)
2602 13832 : return;
2603 :
2604 : /*
2605 : * If clause can't be used as an indexqual because it must wait till after
2606 : * some lower-security-level restriction clause, reject it.
2607 : */
2608 1095516 : if (!restriction_is_securely_promotable(rinfo, index->rel))
2609 522 : return;
2610 :
2611 : /* OK, check each index key column for a match */
2612 2404434 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
2613 : {
2614 : IndexClause *iclause;
2615 : ListCell *lc;
2616 :
2617 : /* Ignore duplicates */
2618 1812958 : foreach(lc, clauseset->indexclauses[indexcol])
2619 : {
2620 80030 : iclause = (IndexClause *) lfirst(lc);
2621 :
2622 80030 : if (iclause->rinfo == rinfo)
2623 0 : return;
2624 : }
2625 :
2626 : /* OK, try to match the clause to the index column */
2627 1732928 : iclause = match_clause_to_indexcol(root,
2628 : rinfo,
2629 : indexcol,
2630 : index);
2631 1732928 : if (iclause)
2632 : {
2633 : /* Success, so record it */
2634 423488 : clauseset->indexclauses[indexcol] =
2635 423488 : lappend(clauseset->indexclauses[indexcol], iclause);
2636 423488 : clauseset->nonempty = true;
2637 423488 : return;
2638 : }
2639 : }
2640 : }
2641 :
2642 : /*
2643 : * match_clause_to_indexcol()
2644 : * Determine whether a restriction clause matches a column of an index,
2645 : * and if so, build an IndexClause node describing the details.
2646 : *
2647 : * To match an index normally, an operator clause:
2648 : *
2649 : * (1) must be in the form (indexkey op const) or (const op indexkey);
2650 : * and
2651 : * (2) must contain an operator which is in the index's operator family
2652 : * for this column; and
2653 : * (3) must match the collation of the index, if collation is relevant.
2654 : *
2655 : * Our definition of "const" is exceedingly liberal: we allow anything that
2656 : * doesn't involve a volatile function or a Var of the index's relation.
2657 : * In particular, Vars belonging to other relations of the query are
2658 : * accepted here, since a clause of that form can be used in a
2659 : * parameterized indexscan. It's the responsibility of higher code levels
2660 : * to manage restriction and join clauses appropriately.
2661 : *
2662 : * Note: we do need to check for Vars of the index's relation on the
2663 : * "const" side of the clause, since clauses like (a.f1 OP (b.f2 OP a.f3))
2664 : * are not processable by a parameterized indexscan on a.f1, whereas
2665 : * something like (a.f1 OP (b.f2 OP c.f3)) is.
2666 : *
2667 : * Presently, the executor can only deal with indexquals that have the
2668 : * indexkey on the left, so we can only use clauses that have the indexkey
2669 : * on the right if we can commute the clause to put the key on the left.
2670 : * We handle that by generating an IndexClause with the correctly-commuted
2671 : * opclause as a derived indexqual.
2672 : *
2673 : * If the index has a collation, the clause must have the same collation.
2674 : * For collation-less indexes, we assume it doesn't matter; this is
2675 : * necessary for cases like "hstore ? text", wherein hstore's operators
2676 : * don't care about collation but the clause will get marked with a
2677 : * collation anyway because of the text argument. (This logic is
2678 : * embodied in the macro IndexCollMatchesExprColl.)
2679 : *
2680 : * It is also possible to match RowCompareExpr clauses to indexes (but
2681 : * currently, only btree indexes handle this).
2682 : *
2683 : * It is also possible to match ScalarArrayOpExpr clauses to indexes, when
2684 : * the clause is of the form "indexkey op ANY (arrayconst)".
2685 : *
2686 : * It is also possible to match a list of OR clauses if it might be
2687 : * transformed into a single ScalarArrayOpExpr clause. On success,
2688 : * the returning index clause will contain a transformed clause.
2689 : *
2690 : * For boolean indexes, it is also possible to match the clause directly
2691 : * to the indexkey; or perhaps the clause is (NOT indexkey).
2692 : *
2693 : * And, last but not least, some operators and functions can be processed
2694 : * to derive (typically lossy) indexquals from a clause that isn't in
2695 : * itself indexable. If we see that any operand of an OpExpr or FuncExpr
2696 : * matches the index key, and the function has a planner support function
2697 : * attached to it, we'll invoke the support function to see if such an
2698 : * indexqual can be built.
2699 : *
2700 : * 'rinfo' is the clause to be tested (as a RestrictInfo node).
2701 : * 'indexcol' is a column number of 'index' (counting from 0).
2702 : * 'index' is the index of interest.
2703 : *
2704 : * Returns an IndexClause if the clause can be used with this index key,
2705 : * or NULL if not.
2706 : *
2707 : * NOTE: This routine always returns NULL if the clause is an AND clause.
2708 : * Higher-level routines deal with OR and AND clauses. OR clause can be
2709 : * matched as a whole by match_orclause_to_indexcol() though.
2710 : */
2711 : static IndexClause *
2712 1732928 : match_clause_to_indexcol(PlannerInfo *root,
2713 : RestrictInfo *rinfo,
2714 : int indexcol,
2715 : IndexOptInfo *index)
2716 : {
2717 : IndexClause *iclause;
2718 1732928 : Expr *clause = rinfo->clause;
2719 : Oid opfamily;
2720 :
2721 : Assert(indexcol < index->nkeycolumns);
2722 :
2723 : /*
2724 : * Historically this code has coped with NULL clauses. That's probably
2725 : * not possible anymore, but we might as well continue to cope.
2726 : */
2727 1732928 : if (clause == NULL)
2728 0 : return NULL;
2729 :
2730 : /* First check for boolean-index cases. */
2731 1732928 : opfamily = index->opfamily[indexcol];
2732 1732928 : if (IsBooleanOpfamily(opfamily))
2733 : {
2734 490 : iclause = match_boolean_index_clause(root, rinfo, indexcol, index);
2735 490 : if (iclause)
2736 314 : return iclause;
2737 : }
2738 :
2739 : /*
2740 : * Clause must be an opclause, funcclause, ScalarArrayOpExpr,
2741 : * RowCompareExpr, or OR-clause that could be converted to SAOP. Or, if
2742 : * the index supports it, we can handle IS NULL/NOT NULL clauses.
2743 : */
2744 1732614 : if (IsA(clause, OpExpr))
2745 : {
2746 1456112 : return match_opclause_to_indexcol(root, rinfo, indexcol, index);
2747 : }
2748 276502 : else if (IsA(clause, FuncExpr))
2749 : {
2750 29990 : return match_funcclause_to_indexcol(root, rinfo, indexcol, index);
2751 : }
2752 246512 : else if (IsA(clause, ScalarArrayOpExpr))
2753 : {
2754 80228 : return match_saopclause_to_indexcol(root, rinfo, indexcol, index);
2755 : }
2756 166284 : else if (IsA(clause, RowCompareExpr))
2757 : {
2758 504 : return match_rowcompare_to_indexcol(root, rinfo, indexcol, index);
2759 : }
2760 165780 : else if (restriction_is_or_clause(rinfo))
2761 : {
2762 43994 : return match_orclause_to_indexcol(root, rinfo, indexcol, index);
2763 : }
2764 121786 : else if (index->amsearchnulls && IsA(clause, NullTest))
2765 : {
2766 15640 : NullTest *nt = (NullTest *) clause;
2767 :
2768 31280 : if (!nt->argisrow &&
2769 15640 : match_index_to_operand((Node *) nt->arg, indexcol, index))
2770 : {
2771 1448 : iclause = makeNode(IndexClause);
2772 1448 : iclause->rinfo = rinfo;
2773 1448 : iclause->indexquals = list_make1(rinfo);
2774 1448 : iclause->lossy = false;
2775 1448 : iclause->indexcol = indexcol;
2776 1448 : iclause->indexcols = NIL;
2777 1448 : return iclause;
2778 : }
2779 : }
2780 :
2781 120338 : return NULL;
2782 : }
2783 :
2784 : /*
2785 : * IsBooleanOpfamily
2786 : * Detect whether an opfamily supports boolean equality as an operator.
2787 : *
2788 : * If the opfamily OID is in the range of built-in objects, we can rely
2789 : * on hard-wired knowledge of which built-in opfamilies support this.
2790 : * For extension opfamilies, there's no choice but to do a catcache lookup.
2791 : */
2792 : static bool
2793 2403332 : IsBooleanOpfamily(Oid opfamily)
2794 : {
2795 2403332 : if (opfamily < FirstNormalObjectId)
2796 2399694 : return IsBuiltinBooleanOpfamily(opfamily);
2797 : else
2798 3638 : return op_in_opfamily(BooleanEqualOperator, opfamily);
2799 : }
2800 :
2801 : /*
2802 : * match_boolean_index_clause
2803 : * Recognize restriction clauses that can be matched to a boolean index.
2804 : *
2805 : * The idea here is that, for an index on a boolean column that supports the
2806 : * BooleanEqualOperator, we can transform a plain reference to the indexkey
2807 : * into "indexkey = true", or "NOT indexkey" into "indexkey = false", etc,
2808 : * so as to make the expression indexable using the index's "=" operator.
2809 : * Since Postgres 8.1, we must do this because constant simplification does
2810 : * the reverse transformation; without this code there'd be no way to use
2811 : * such an index at all.
2812 : *
2813 : * This should be called only when IsBooleanOpfamily() recognizes the
2814 : * index's operator family. We check to see if the clause matches the
2815 : * index's key, and if so, build a suitable IndexClause.
2816 : */
2817 : static IndexClause *
2818 1782 : match_boolean_index_clause(PlannerInfo *root,
2819 : RestrictInfo *rinfo,
2820 : int indexcol,
2821 : IndexOptInfo *index)
2822 : {
2823 1782 : Node *clause = (Node *) rinfo->clause;
2824 1782 : Expr *op = NULL;
2825 :
2826 : /* Direct match? */
2827 1782 : if (match_index_to_operand(clause, indexcol, index))
2828 : {
2829 : /* convert to indexkey = TRUE */
2830 314 : op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2831 : (Expr *) clause,
2832 314 : (Expr *) makeBoolConst(true, false),
2833 : InvalidOid, InvalidOid);
2834 : }
2835 : /* NOT clause? */
2836 1468 : else if (is_notclause(clause))
2837 : {
2838 1208 : Node *arg = (Node *) get_notclausearg((Expr *) clause);
2839 :
2840 1208 : if (match_index_to_operand(arg, indexcol, index))
2841 : {
2842 : /* convert to indexkey = FALSE */
2843 1208 : op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2844 : (Expr *) arg,
2845 1208 : (Expr *) makeBoolConst(false, false),
2846 : InvalidOid, InvalidOid);
2847 : }
2848 : }
2849 :
2850 : /*
2851 : * Since we only consider clauses at top level of WHERE, we can convert
2852 : * indexkey IS TRUE and indexkey IS FALSE to index searches as well. The
2853 : * different meaning for NULL isn't important.
2854 : */
2855 260 : else if (clause && IsA(clause, BooleanTest))
2856 : {
2857 48 : BooleanTest *btest = (BooleanTest *) clause;
2858 48 : Node *arg = (Node *) btest->arg;
2859 :
2860 78 : if (btest->booltesttype == IS_TRUE &&
2861 30 : match_index_to_operand(arg, indexcol, index))
2862 : {
2863 : /* convert to indexkey = TRUE */
2864 30 : op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2865 : (Expr *) arg,
2866 30 : (Expr *) makeBoolConst(true, false),
2867 : InvalidOid, InvalidOid);
2868 : }
2869 36 : else if (btest->booltesttype == IS_FALSE &&
2870 18 : match_index_to_operand(arg, indexcol, index))
2871 : {
2872 : /* convert to indexkey = FALSE */
2873 18 : op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2874 : (Expr *) arg,
2875 18 : (Expr *) makeBoolConst(false, false),
2876 : InvalidOid, InvalidOid);
2877 : }
2878 : }
2879 :
2880 : /*
2881 : * If we successfully made an operator clause from the given qual, we must
2882 : * wrap it in an IndexClause. It's not lossy.
2883 : */
2884 1782 : if (op)
2885 : {
2886 1570 : IndexClause *iclause = makeNode(IndexClause);
2887 :
2888 1570 : iclause->rinfo = rinfo;
2889 1570 : iclause->indexquals = list_make1(make_simple_restrictinfo(root, op));
2890 1570 : iclause->lossy = false;
2891 1570 : iclause->indexcol = indexcol;
2892 1570 : iclause->indexcols = NIL;
2893 1570 : return iclause;
2894 : }
2895 :
2896 212 : return NULL;
2897 : }
2898 :
2899 : /*
2900 : * match_opclause_to_indexcol()
2901 : * Handles the OpExpr case for match_clause_to_indexcol(),
2902 : * which see for comments.
2903 : */
2904 : static IndexClause *
2905 1456112 : match_opclause_to_indexcol(PlannerInfo *root,
2906 : RestrictInfo *rinfo,
2907 : int indexcol,
2908 : IndexOptInfo *index)
2909 : {
2910 : IndexClause *iclause;
2911 1456112 : OpExpr *clause = (OpExpr *) rinfo->clause;
2912 : Node *leftop,
2913 : *rightop;
2914 : Oid expr_op;
2915 : Oid expr_coll;
2916 : Index index_relid;
2917 : Oid opfamily;
2918 : Oid idxcollation;
2919 :
2920 : /*
2921 : * Only binary operators need apply. (In theory, a planner support
2922 : * function could do something with a unary operator, but it seems
2923 : * unlikely to be worth the cycles to check.)
2924 : */
2925 1456112 : if (list_length(clause->args) != 2)
2926 0 : return NULL;
2927 :
2928 1456112 : leftop = (Node *) linitial(clause->args);
2929 1456112 : rightop = (Node *) lsecond(clause->args);
2930 1456112 : expr_op = clause->opno;
2931 1456112 : expr_coll = clause->inputcollid;
2932 :
2933 1456112 : index_relid = index->rel->relid;
2934 1456112 : opfamily = index->opfamily[indexcol];
2935 1456112 : idxcollation = index->indexcollations[indexcol];
2936 :
2937 : /*
2938 : * Check for clauses of the form: (indexkey operator constant) or
2939 : * (constant operator indexkey). See match_clause_to_indexcol's notes
2940 : * about const-ness.
2941 : *
2942 : * Note that we don't ask the support function about clauses that don't
2943 : * have one of these forms. Again, in principle it might be possible to
2944 : * do something, but it seems unlikely to be worth the cycles to check.
2945 : */
2946 1456112 : if (match_index_to_operand(leftop, indexcol, index) &&
2947 357666 : !bms_is_member(index_relid, rinfo->right_relids) &&
2948 357480 : !contain_volatile_functions(rightop))
2949 : {
2950 708226 : if (IndexCollMatchesExprColl(idxcollation, expr_coll) &&
2951 350746 : op_in_opfamily(expr_op, opfamily))
2952 : {
2953 343150 : iclause = makeNode(IndexClause);
2954 343150 : iclause->rinfo = rinfo;
2955 343150 : iclause->indexquals = list_make1(rinfo);
2956 343150 : iclause->lossy = false;
2957 343150 : iclause->indexcol = indexcol;
2958 343150 : iclause->indexcols = NIL;
2959 343150 : return iclause;
2960 : }
2961 :
2962 : /*
2963 : * If we didn't find a member of the index's opfamily, try the support
2964 : * function for the operator's underlying function.
2965 : */
2966 14330 : set_opfuncid(clause); /* make sure we have opfuncid */
2967 14330 : return get_index_clause_from_support(root,
2968 : rinfo,
2969 : clause->opfuncid,
2970 : 0, /* indexarg on left */
2971 : indexcol,
2972 : index);
2973 : }
2974 :
2975 1098632 : if (match_index_to_operand(rightop, indexcol, index) &&
2976 69188 : !bms_is_member(index_relid, rinfo->left_relids) &&
2977 69062 : !contain_volatile_functions(leftop))
2978 : {
2979 69062 : if (IndexCollMatchesExprColl(idxcollation, expr_coll))
2980 : {
2981 69050 : Oid comm_op = get_commutator(expr_op);
2982 :
2983 138100 : if (OidIsValid(comm_op) &&
2984 69050 : op_in_opfamily(comm_op, opfamily))
2985 : {
2986 : RestrictInfo *commrinfo;
2987 :
2988 : /* Build a commuted OpExpr and RestrictInfo */
2989 68574 : commrinfo = commute_restrictinfo(rinfo, comm_op);
2990 :
2991 : /* Make an IndexClause showing that as a derived qual */
2992 68574 : iclause = makeNode(IndexClause);
2993 68574 : iclause->rinfo = rinfo;
2994 68574 : iclause->indexquals = list_make1(commrinfo);
2995 68574 : iclause->lossy = false;
2996 68574 : iclause->indexcol = indexcol;
2997 68574 : iclause->indexcols = NIL;
2998 68574 : return iclause;
2999 : }
3000 : }
3001 :
3002 : /*
3003 : * If we didn't find a member of the index's opfamily, try the support
3004 : * function for the operator's underlying function.
3005 : */
3006 488 : set_opfuncid(clause); /* make sure we have opfuncid */
3007 488 : return get_index_clause_from_support(root,
3008 : rinfo,
3009 : clause->opfuncid,
3010 : 1, /* indexarg on right */
3011 : indexcol,
3012 : index);
3013 : }
3014 :
3015 1029570 : return NULL;
3016 : }
3017 :
3018 : /*
3019 : * match_funcclause_to_indexcol()
3020 : * Handles the FuncExpr case for match_clause_to_indexcol(),
3021 : * which see for comments.
3022 : */
3023 : static IndexClause *
3024 29990 : match_funcclause_to_indexcol(PlannerInfo *root,
3025 : RestrictInfo *rinfo,
3026 : int indexcol,
3027 : IndexOptInfo *index)
3028 : {
3029 29990 : FuncExpr *clause = (FuncExpr *) rinfo->clause;
3030 : int indexarg;
3031 : ListCell *lc;
3032 :
3033 : /*
3034 : * We have no built-in intelligence about function clauses, but if there's
3035 : * a planner support function, it might be able to do something. But, to
3036 : * cut down on wasted planning cycles, only call the support function if
3037 : * at least one argument matches the target index column.
3038 : *
3039 : * Note that we don't insist on the other arguments being pseudoconstants;
3040 : * the support function has to check that. This is to allow cases where
3041 : * only some of the other arguments need to be included in the indexqual.
3042 : */
3043 29990 : indexarg = 0;
3044 64502 : foreach(lc, clause->args)
3045 : {
3046 40336 : Node *op = (Node *) lfirst(lc);
3047 :
3048 40336 : if (match_index_to_operand(op, indexcol, index))
3049 : {
3050 5824 : return get_index_clause_from_support(root,
3051 : rinfo,
3052 : clause->funcid,
3053 : indexarg,
3054 : indexcol,
3055 : index);
3056 : }
3057 :
3058 34512 : indexarg++;
3059 : }
3060 :
3061 24166 : return NULL;
3062 : }
3063 :
3064 : /*
3065 : * get_index_clause_from_support()
3066 : * If the function has a planner support function, try to construct
3067 : * an IndexClause using indexquals created by the support function.
3068 : */
3069 : static IndexClause *
3070 20642 : get_index_clause_from_support(PlannerInfo *root,
3071 : RestrictInfo *rinfo,
3072 : Oid funcid,
3073 : int indexarg,
3074 : int indexcol,
3075 : IndexOptInfo *index)
3076 : {
3077 20642 : Oid prosupport = get_func_support(funcid);
3078 : SupportRequestIndexCondition req;
3079 : List *sresult;
3080 :
3081 20642 : if (!OidIsValid(prosupport))
3082 12432 : return NULL;
3083 :
3084 8210 : req.type = T_SupportRequestIndexCondition;
3085 8210 : req.root = root;
3086 8210 : req.funcid = funcid;
3087 8210 : req.node = (Node *) rinfo->clause;
3088 8210 : req.indexarg = indexarg;
3089 8210 : req.index = index;
3090 8210 : req.indexcol = indexcol;
3091 8210 : req.opfamily = index->opfamily[indexcol];
3092 8210 : req.indexcollation = index->indexcollations[indexcol];
3093 :
3094 8210 : req.lossy = true; /* default assumption */
3095 :
3096 : sresult = (List *)
3097 8210 : DatumGetPointer(OidFunctionCall1(prosupport,
3098 : PointerGetDatum(&req)));
3099 :
3100 8210 : if (sresult != NIL)
3101 : {
3102 1406 : IndexClause *iclause = makeNode(IndexClause);
3103 1406 : List *indexquals = NIL;
3104 : ListCell *lc;
3105 :
3106 : /*
3107 : * The support function API says it should just give back bare
3108 : * clauses, so here we must wrap each one in a RestrictInfo.
3109 : */
3110 4140 : foreach(lc, sresult)
3111 : {
3112 2734 : Expr *clause = (Expr *) lfirst(lc);
3113 :
3114 2734 : indexquals = lappend(indexquals,
3115 2734 : make_simple_restrictinfo(root, clause));
3116 : }
3117 :
3118 1406 : iclause->rinfo = rinfo;
3119 1406 : iclause->indexquals = indexquals;
3120 1406 : iclause->lossy = req.lossy;
3121 1406 : iclause->indexcol = indexcol;
3122 1406 : iclause->indexcols = NIL;
3123 :
3124 1406 : return iclause;
3125 : }
3126 :
3127 6804 : return NULL;
3128 : }
3129 :
3130 : /*
3131 : * match_saopclause_to_indexcol()
3132 : * Handles the ScalarArrayOpExpr case for match_clause_to_indexcol(),
3133 : * which see for comments.
3134 : */
3135 : static IndexClause *
3136 80228 : match_saopclause_to_indexcol(PlannerInfo *root,
3137 : RestrictInfo *rinfo,
3138 : int indexcol,
3139 : IndexOptInfo *index)
3140 : {
3141 80228 : ScalarArrayOpExpr *saop = (ScalarArrayOpExpr *) rinfo->clause;
3142 : Node *leftop,
3143 : *rightop;
3144 : Relids right_relids;
3145 : Oid expr_op;
3146 : Oid expr_coll;
3147 : Index index_relid;
3148 : Oid opfamily;
3149 : Oid idxcollation;
3150 :
3151 : /* We only accept ANY clauses, not ALL */
3152 80228 : if (!saop->useOr)
3153 9322 : return NULL;
3154 70906 : leftop = (Node *) linitial(saop->args);
3155 70906 : rightop = (Node *) lsecond(saop->args);
3156 70906 : right_relids = pull_varnos(root, rightop);
3157 70906 : expr_op = saop->opno;
3158 70906 : expr_coll = saop->inputcollid;
3159 :
3160 70906 : index_relid = index->rel->relid;
3161 70906 : opfamily = index->opfamily[indexcol];
3162 70906 : idxcollation = index->indexcollations[indexcol];
3163 :
3164 : /*
3165 : * We must have indexkey on the left and a pseudo-constant array argument.
3166 : */
3167 70906 : if (match_index_to_operand(leftop, indexcol, index) &&
3168 7378 : !bms_is_member(index_relid, right_relids) &&
3169 7378 : !contain_volatile_functions(rightop))
3170 : {
3171 14750 : if (IndexCollMatchesExprColl(idxcollation, expr_coll) &&
3172 7372 : op_in_opfamily(expr_op, opfamily))
3173 : {
3174 7360 : IndexClause *iclause = makeNode(IndexClause);
3175 :
3176 7360 : iclause->rinfo = rinfo;
3177 7360 : iclause->indexquals = list_make1(rinfo);
3178 7360 : iclause->lossy = false;
3179 7360 : iclause->indexcol = indexcol;
3180 7360 : iclause->indexcols = NIL;
3181 7360 : return iclause;
3182 : }
3183 :
3184 : /*
3185 : * We do not currently ask support functions about ScalarArrayOpExprs,
3186 : * though in principle we could.
3187 : */
3188 : }
3189 :
3190 63546 : return NULL;
3191 : }
3192 :
3193 : /*
3194 : * match_rowcompare_to_indexcol()
3195 : * Handles the RowCompareExpr case for match_clause_to_indexcol(),
3196 : * which see for comments.
3197 : *
3198 : * In this routine we check whether the first column of the row comparison
3199 : * matches the target index column. This is sufficient to guarantee that some
3200 : * index condition can be constructed from the RowCompareExpr --- the rest
3201 : * is handled by expand_indexqual_rowcompare().
3202 : */
3203 : static IndexClause *
3204 504 : match_rowcompare_to_indexcol(PlannerInfo *root,
3205 : RestrictInfo *rinfo,
3206 : int indexcol,
3207 : IndexOptInfo *index)
3208 : {
3209 504 : RowCompareExpr *clause = (RowCompareExpr *) rinfo->clause;
3210 : Index index_relid;
3211 : Oid opfamily;
3212 : Oid idxcollation;
3213 : Node *leftop,
3214 : *rightop;
3215 : bool var_on_left;
3216 : Oid expr_op;
3217 : Oid expr_coll;
3218 :
3219 : /* Forget it if we're not dealing with a btree index */
3220 504 : if (index->relam != BTREE_AM_OID)
3221 0 : return NULL;
3222 :
3223 504 : index_relid = index->rel->relid;
3224 504 : opfamily = index->opfamily[indexcol];
3225 504 : idxcollation = index->indexcollations[indexcol];
3226 :
3227 : /*
3228 : * We could do the matching on the basis of insisting that the opfamily
3229 : * shown in the RowCompareExpr be the same as the index column's opfamily,
3230 : * but that could fail in the presence of reverse-sort opfamilies: it'd be
3231 : * a matter of chance whether RowCompareExpr had picked the forward or
3232 : * reverse-sort family. So look only at the operator, and match if it is
3233 : * a member of the index's opfamily (after commutation, if the indexkey is
3234 : * on the right). We'll worry later about whether any additional
3235 : * operators are matchable to the index.
3236 : */
3237 504 : leftop = (Node *) linitial(clause->largs);
3238 504 : rightop = (Node *) linitial(clause->rargs);
3239 504 : expr_op = linitial_oid(clause->opnos);
3240 504 : expr_coll = linitial_oid(clause->inputcollids);
3241 :
3242 : /* Collations must match, if relevant */
3243 504 : if (!IndexCollMatchesExprColl(idxcollation, expr_coll))
3244 0 : return NULL;
3245 :
3246 : /*
3247 : * These syntactic tests are the same as in match_opclause_to_indexcol()
3248 : */
3249 504 : if (match_index_to_operand(leftop, indexcol, index) &&
3250 162 : !bms_is_member(index_relid, pull_varnos(root, rightop)) &&
3251 162 : !contain_volatile_functions(rightop))
3252 : {
3253 : /* OK, indexkey is on left */
3254 162 : var_on_left = true;
3255 : }
3256 342 : else if (match_index_to_operand(rightop, indexcol, index) &&
3257 24 : !bms_is_member(index_relid, pull_varnos(root, leftop)) &&
3258 24 : !contain_volatile_functions(leftop))
3259 : {
3260 : /* indexkey is on right, so commute the operator */
3261 24 : expr_op = get_commutator(expr_op);
3262 24 : if (expr_op == InvalidOid)
3263 0 : return NULL;
3264 24 : var_on_left = false;
3265 : }
3266 : else
3267 318 : return NULL;
3268 :
3269 : /* We're good if the operator is the right type of opfamily member */
3270 186 : switch (get_op_opfamily_strategy(expr_op, opfamily))
3271 : {
3272 186 : case BTLessStrategyNumber:
3273 : case BTLessEqualStrategyNumber:
3274 : case BTGreaterEqualStrategyNumber:
3275 : case BTGreaterStrategyNumber:
3276 186 : return expand_indexqual_rowcompare(root,
3277 : rinfo,
3278 : indexcol,
3279 : index,
3280 : expr_op,
3281 : var_on_left);
3282 : }
3283 :
3284 0 : return NULL;
3285 : }
3286 :
3287 : /*
3288 : * match_orclause_to_indexcol()
3289 : * Handles the OR-expr case for match_clause_to_indexcol() in the case
3290 : * when it could be transformed to ScalarArrayOpExpr.
3291 : *
3292 : * In this routine, we attempt to transform a list of OR-clause args into a
3293 : * single SAOP expression matching the target index column. On success,
3294 : * return an IndexClause containing the transformed expression.
3295 : * Return NULL if the transformation fails.
3296 : */
3297 : static IndexClause *
3298 43994 : match_orclause_to_indexcol(PlannerInfo *root,
3299 : RestrictInfo *rinfo,
3300 : int indexcol,
3301 : IndexOptInfo *index)
3302 : {
3303 43994 : BoolExpr *orclause = (BoolExpr *) rinfo->orclause;
3304 43994 : List *consts = NIL;
3305 43994 : Node *indexExpr = NULL;
3306 43994 : Oid matchOpno = InvalidOid;
3307 43994 : Oid consttype = InvalidOid;
3308 43994 : Oid arraytype = InvalidOid;
3309 43994 : Oid inputcollid = InvalidOid;
3310 43994 : bool firstTime = true;
3311 43994 : bool haveNonConst = false;
3312 43994 : Index indexRelid = index->rel->relid;
3313 : ScalarArrayOpExpr *saopexpr;
3314 : IndexClause *iclause;
3315 : ListCell *lc;
3316 :
3317 : /* Forget it if index doesn't support SAOP clauses */
3318 43994 : if (!index->amsearcharray)
3319 106 : return NULL;
3320 :
3321 : /*
3322 : * Try to convert a list of OR-clauses to a single SAOP expression. Each
3323 : * OR entry must be in the form: (indexkey operator constant) or (constant
3324 : * operator indexkey). Operators of all the entries must match. On
3325 : * discovery of anything unsupported, we give up by breaking out of the
3326 : * loop immediately and returning NULL.
3327 : */
3328 48468 : foreach(lc, orclause->args)
3329 : {
3330 47418 : RestrictInfo *subRinfo = (RestrictInfo *) lfirst(lc);
3331 : OpExpr *subClause;
3332 : Oid opno;
3333 : Node *leftop,
3334 : *rightop;
3335 : Node *constExpr;
3336 :
3337 : /* If it's not a RestrictInfo (i.e. it's a sub-AND), we can't use it */
3338 47418 : if (!IsA(subRinfo, RestrictInfo))
3339 5286 : break;
3340 :
3341 : /* Only operator clauses can match */
3342 42132 : if (!IsA(subRinfo->clause, OpExpr))
3343 12944 : break;
3344 :
3345 29188 : subClause = (OpExpr *) subRinfo->clause;
3346 29188 : opno = subClause->opno;
3347 :
3348 : /* Only binary operators can match */
3349 29188 : if (list_length(subClause->args) != 2)
3350 0 : break;
3351 :
3352 : /*
3353 : * Check for clauses of the form: (indexkey operator constant) or
3354 : * (constant operator indexkey). These tests should agree with
3355 : * match_opclause_to_indexcol.
3356 : */
3357 29188 : leftop = (Node *) linitial(subClause->args);
3358 29188 : rightop = (Node *) lsecond(subClause->args);
3359 29188 : if (match_index_to_operand(leftop, indexcol, index) &&
3360 6424 : !bms_is_member(indexRelid, subRinfo->right_relids) &&
3361 6394 : !contain_volatile_functions(rightop))
3362 : {
3363 6394 : indexExpr = leftop;
3364 6394 : constExpr = rightop;
3365 : }
3366 22794 : else if (match_index_to_operand(rightop, indexcol, index) &&
3367 194 : !bms_is_member(indexRelid, subRinfo->left_relids) &&
3368 188 : !contain_volatile_functions(leftop))
3369 : {
3370 188 : opno = get_commutator(opno);
3371 188 : if (!OidIsValid(opno))
3372 : {
3373 : /* commutator doesn't exist, we can't reverse the order */
3374 0 : break;
3375 : }
3376 188 : indexExpr = rightop;
3377 188 : constExpr = leftop;
3378 : }
3379 : else
3380 : {
3381 : break;
3382 : }
3383 :
3384 : /*
3385 : * Save information about the operator, type, and collation for the
3386 : * first matching qual. Then, check that subsequent quals match the
3387 : * first.
3388 : */
3389 6582 : if (firstTime)
3390 : {
3391 4824 : matchOpno = opno;
3392 4824 : consttype = exprType(constExpr);
3393 4824 : arraytype = get_array_type(consttype);
3394 4824 : inputcollid = subClause->inputcollid;
3395 :
3396 : /*
3397 : * Check that the operator is presented in the opfamily and that
3398 : * the expression collation matches the index collation. Also,
3399 : * there must be an array type to construct an array later.
3400 : */
3401 4824 : if (!IndexCollMatchesExprColl(index->indexcollations[indexcol],
3402 4698 : inputcollid) ||
3403 4698 : !op_in_opfamily(matchOpno, index->opfamily[indexcol]) ||
3404 : !OidIsValid(arraytype))
3405 : break;
3406 :
3407 : /*
3408 : * Disallow if either type is RECORD, mainly because we can't be
3409 : * positive that all the RHS expressions are the same record type.
3410 : */
3411 2966 : if (consttype == RECORDOID || exprType(indexExpr) == RECORDOID)
3412 : break;
3413 :
3414 2966 : firstTime = false;
3415 : }
3416 : else
3417 : {
3418 1758 : if (matchOpno != opno ||
3419 3228 : inputcollid != subClause->inputcollid ||
3420 1614 : consttype != exprType(constExpr))
3421 : break;
3422 : }
3423 :
3424 : /*
3425 : * The righthand inputs don't necessarily have to be plain Consts, but
3426 : * make_SAOP_expr needs to know if any are not.
3427 : */
3428 4580 : if (!IsA(constExpr, Const))
3429 368 : haveNonConst = true;
3430 :
3431 4580 : consts = lappend(consts, constExpr);
3432 : }
3433 :
3434 : /*
3435 : * Handle failed conversion from breaking out of the loop because of an
3436 : * unsupported qual. Also check that we have an indexExpr, just in case
3437 : * the OR list was somehow empty (it shouldn't be). Return NULL to
3438 : * indicate the conversion failed.
3439 : */
3440 43888 : if (lc != NULL || indexExpr == NULL)
3441 : {
3442 42838 : list_free(consts); /* might as well */
3443 42838 : return NULL;
3444 : }
3445 :
3446 : /*
3447 : * Build the new SAOP node. We use the indexExpr from the last OR arm;
3448 : * since all the arms passed match_index_to_operand, it shouldn't matter
3449 : * which one we use. But using "inputcollid" twice is a bit of a cheat:
3450 : * we might end up with an array Const node that is labeled with a
3451 : * collation despite its elements being of a noncollatable type. But
3452 : * nothing is likely to complain about that, so we don't bother being more
3453 : * accurate.
3454 : */
3455 1050 : saopexpr = make_SAOP_expr(matchOpno, indexExpr, consttype, inputcollid,
3456 : inputcollid, consts, haveNonConst);
3457 : Assert(saopexpr != NULL);
3458 :
3459 : /*
3460 : * Finally, build an IndexClause based on the SAOP node. It's not lossy.
3461 : */
3462 1050 : iclause = makeNode(IndexClause);
3463 1050 : iclause->rinfo = rinfo;
3464 1050 : iclause->indexquals = list_make1(make_simple_restrictinfo(root,
3465 : (Expr *) saopexpr));
3466 1050 : iclause->lossy = false;
3467 1050 : iclause->indexcol = indexcol;
3468 1050 : iclause->indexcols = NIL;
3469 1050 : return iclause;
3470 : }
3471 :
3472 : /*
3473 : * expand_indexqual_rowcompare --- expand a single indexqual condition
3474 : * that is a RowCompareExpr
3475 : *
3476 : * It's already known that the first column of the row comparison matches
3477 : * the specified column of the index. We can use additional columns of the
3478 : * row comparison as index qualifications, so long as they match the index
3479 : * in the "same direction", ie, the indexkeys are all on the same side of the
3480 : * clause and the operators are all the same-type members of the opfamilies.
3481 : *
3482 : * If all the columns of the RowCompareExpr match in this way, we just use it
3483 : * as-is, except for possibly commuting it to put the indexkeys on the left.
3484 : *
3485 : * Otherwise, we build a shortened RowCompareExpr (if more than one
3486 : * column matches) or a simple OpExpr (if the first-column match is all
3487 : * there is). In these cases the modified clause is always "<=" or ">="
3488 : * even when the original was "<" or ">" --- this is necessary to match all
3489 : * the rows that could match the original. (We are building a lossy version
3490 : * of the row comparison when we do this, so we set lossy = true.)
3491 : *
3492 : * Note: this is really just the last half of match_rowcompare_to_indexcol,
3493 : * but we split it out for comprehensibility.
3494 : */
3495 : static IndexClause *
3496 186 : expand_indexqual_rowcompare(PlannerInfo *root,
3497 : RestrictInfo *rinfo,
3498 : int indexcol,
3499 : IndexOptInfo *index,
3500 : Oid expr_op,
3501 : bool var_on_left)
3502 : {
3503 186 : IndexClause *iclause = makeNode(IndexClause);
3504 186 : RowCompareExpr *clause = (RowCompareExpr *) rinfo->clause;
3505 : int op_strategy;
3506 : Oid op_lefttype;
3507 : Oid op_righttype;
3508 : int matching_cols;
3509 : List *expr_ops;
3510 : List *opfamilies;
3511 : List *lefttypes;
3512 : List *righttypes;
3513 : List *new_ops;
3514 : List *var_args;
3515 : List *non_var_args;
3516 :
3517 186 : iclause->rinfo = rinfo;
3518 186 : iclause->indexcol = indexcol;
3519 :
3520 186 : if (var_on_left)
3521 : {
3522 162 : var_args = clause->largs;
3523 162 : non_var_args = clause->rargs;
3524 : }
3525 : else
3526 : {
3527 24 : var_args = clause->rargs;
3528 24 : non_var_args = clause->largs;
3529 : }
3530 :
3531 186 : get_op_opfamily_properties(expr_op, index->opfamily[indexcol], false,
3532 : &op_strategy,
3533 : &op_lefttype,
3534 : &op_righttype);
3535 :
3536 : /* Initialize returned list of which index columns are used */
3537 186 : iclause->indexcols = list_make1_int(indexcol);
3538 :
3539 : /* Build lists of ops, opfamilies and operator datatypes in case needed */
3540 186 : expr_ops = list_make1_oid(expr_op);
3541 186 : opfamilies = list_make1_oid(index->opfamily[indexcol]);
3542 186 : lefttypes = list_make1_oid(op_lefttype);
3543 186 : righttypes = list_make1_oid(op_righttype);
3544 :
3545 : /*
3546 : * See how many of the remaining columns match some index column in the
3547 : * same way. As in match_clause_to_indexcol(), the "other" side of any
3548 : * potential index condition is OK as long as it doesn't use Vars from the
3549 : * indexed relation.
3550 : */
3551 186 : matching_cols = 1;
3552 :
3553 354 : while (matching_cols < list_length(var_args))
3554 : {
3555 222 : Node *varop = (Node *) list_nth(var_args, matching_cols);
3556 222 : Node *constop = (Node *) list_nth(non_var_args, matching_cols);
3557 : int i;
3558 :
3559 222 : expr_op = list_nth_oid(clause->opnos, matching_cols);
3560 222 : if (!var_on_left)
3561 : {
3562 : /* indexkey is on right, so commute the operator */
3563 24 : expr_op = get_commutator(expr_op);
3564 24 : if (expr_op == InvalidOid)
3565 0 : break; /* operator is not usable */
3566 : }
3567 222 : if (bms_is_member(index->rel->relid, pull_varnos(root, constop)))
3568 0 : break; /* no good, Var on wrong side */
3569 222 : if (contain_volatile_functions(constop))
3570 0 : break; /* no good, volatile comparison value */
3571 :
3572 : /*
3573 : * The Var side can match any key column of the index.
3574 : */
3575 516 : for (i = 0; i < index->nkeycolumns; i++)
3576 : {
3577 462 : if (match_index_to_operand(varop, i, index) &&
3578 168 : get_op_opfamily_strategy(expr_op,
3579 168 : index->opfamily[i]) == op_strategy &&
3580 168 : IndexCollMatchesExprColl(index->indexcollations[i],
3581 : list_nth_oid(clause->inputcollids,
3582 : matching_cols)))
3583 : break;
3584 : }
3585 222 : if (i >= index->nkeycolumns)
3586 54 : break; /* no match found */
3587 :
3588 : /* Add column number to returned list */
3589 168 : iclause->indexcols = lappend_int(iclause->indexcols, i);
3590 :
3591 : /* Add operator info to lists */
3592 168 : get_op_opfamily_properties(expr_op, index->opfamily[i], false,
3593 : &op_strategy,
3594 : &op_lefttype,
3595 : &op_righttype);
3596 168 : expr_ops = lappend_oid(expr_ops, expr_op);
3597 168 : opfamilies = lappend_oid(opfamilies, index->opfamily[i]);
3598 168 : lefttypes = lappend_oid(lefttypes, op_lefttype);
3599 168 : righttypes = lappend_oid(righttypes, op_righttype);
3600 :
3601 : /* This column matches, keep scanning */
3602 168 : matching_cols++;
3603 : }
3604 :
3605 : /* Result is non-lossy if all columns are usable as index quals */
3606 186 : iclause->lossy = (matching_cols != list_length(clause->opnos));
3607 :
3608 : /*
3609 : * We can use rinfo->clause as-is if we have var on left and it's all
3610 : * usable as index quals.
3611 : */
3612 186 : if (var_on_left && !iclause->lossy)
3613 120 : iclause->indexquals = list_make1(rinfo);
3614 : else
3615 : {
3616 : /*
3617 : * We have to generate a modified rowcompare (possibly just one
3618 : * OpExpr). The painful part of this is changing < to <= or > to >=,
3619 : * so deal with that first.
3620 : */
3621 66 : if (!iclause->lossy)
3622 : {
3623 : /* very easy, just use the commuted operators */
3624 12 : new_ops = expr_ops;
3625 : }
3626 54 : else if (op_strategy == BTLessEqualStrategyNumber ||
3627 54 : op_strategy == BTGreaterEqualStrategyNumber)
3628 : {
3629 : /* easy, just use the same (possibly commuted) operators */
3630 0 : new_ops = list_truncate(expr_ops, matching_cols);
3631 : }
3632 : else
3633 : {
3634 : ListCell *opfamilies_cell;
3635 : ListCell *lefttypes_cell;
3636 : ListCell *righttypes_cell;
3637 :
3638 54 : if (op_strategy == BTLessStrategyNumber)
3639 30 : op_strategy = BTLessEqualStrategyNumber;
3640 24 : else if (op_strategy == BTGreaterStrategyNumber)
3641 24 : op_strategy = BTGreaterEqualStrategyNumber;
3642 : else
3643 0 : elog(ERROR, "unexpected strategy number %d", op_strategy);
3644 54 : new_ops = NIL;
3645 144 : forthree(opfamilies_cell, opfamilies,
3646 : lefttypes_cell, lefttypes,
3647 : righttypes_cell, righttypes)
3648 : {
3649 90 : Oid opfam = lfirst_oid(opfamilies_cell);
3650 90 : Oid lefttype = lfirst_oid(lefttypes_cell);
3651 90 : Oid righttype = lfirst_oid(righttypes_cell);
3652 :
3653 90 : expr_op = get_opfamily_member(opfam, lefttype, righttype,
3654 : op_strategy);
3655 90 : if (!OidIsValid(expr_op)) /* should not happen */
3656 0 : elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
3657 : op_strategy, lefttype, righttype, opfam);
3658 90 : new_ops = lappend_oid(new_ops, expr_op);
3659 : }
3660 : }
3661 :
3662 : /* If we have more than one matching col, create a subset rowcompare */
3663 66 : if (matching_cols > 1)
3664 : {
3665 48 : RowCompareExpr *rc = makeNode(RowCompareExpr);
3666 :
3667 48 : rc->cmptype = (CompareType) op_strategy;
3668 48 : rc->opnos = new_ops;
3669 48 : rc->opfamilies = list_copy_head(clause->opfamilies,
3670 : matching_cols);
3671 48 : rc->inputcollids = list_copy_head(clause->inputcollids,
3672 : matching_cols);
3673 48 : rc->largs = list_copy_head(var_args, matching_cols);
3674 48 : rc->rargs = list_copy_head(non_var_args, matching_cols);
3675 48 : iclause->indexquals = list_make1(make_simple_restrictinfo(root,
3676 : (Expr *) rc));
3677 : }
3678 : else
3679 : {
3680 : Expr *op;
3681 :
3682 : /* We don't report an index column list in this case */
3683 18 : iclause->indexcols = NIL;
3684 :
3685 18 : op = make_opclause(linitial_oid(new_ops), BOOLOID, false,
3686 18 : copyObject(linitial(var_args)),
3687 18 : copyObject(linitial(non_var_args)),
3688 : InvalidOid,
3689 18 : linitial_oid(clause->inputcollids));
3690 18 : iclause->indexquals = list_make1(make_simple_restrictinfo(root, op));
3691 : }
3692 : }
3693 :
3694 186 : return iclause;
3695 : }
3696 :
3697 :
3698 : /****************************************************************************
3699 : * ---- ROUTINES TO CHECK ORDERING OPERATORS ----
3700 : ****************************************************************************/
3701 :
3702 : /*
3703 : * match_pathkeys_to_index
3704 : * For the given 'index' and 'pathkeys', output a list of suitable ORDER
3705 : * BY expressions, each of the form "indexedcol operator pseudoconstant",
3706 : * along with an integer list of the index column numbers (zero based)
3707 : * that each clause would be used with.
3708 : *
3709 : * This attempts to find an ORDER BY and index column number for all items in
3710 : * the pathkey list, however, if we're unable to match any given pathkey to an
3711 : * index column, we return just the ones matched by the function so far. This
3712 : * allows callers who are interested in partial matches to get them. Callers
3713 : * can determine a partial match vs a full match by checking the outputted
3714 : * list lengths. A full match will have one item in the output lists for each
3715 : * item in the given 'pathkeys' list.
3716 : */
3717 : static void
3718 1074 : match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys,
3719 : List **orderby_clauses_p,
3720 : List **clause_columns_p)
3721 : {
3722 : ListCell *lc1;
3723 :
3724 1074 : *orderby_clauses_p = NIL; /* set default results */
3725 1074 : *clause_columns_p = NIL;
3726 :
3727 : /* Only indexes with the amcanorderbyop property are interesting here */
3728 1074 : if (!index->amcanorderbyop)
3729 0 : return;
3730 :
3731 1548 : foreach(lc1, pathkeys)
3732 : {
3733 1080 : PathKey *pathkey = (PathKey *) lfirst(lc1);
3734 1080 : bool found = false;
3735 : EquivalenceMemberIterator it;
3736 : EquivalenceMember *member;
3737 :
3738 :
3739 : /* Pathkey must request default sort order for the target opfamily */
3740 1080 : if (pathkey->pk_cmptype != COMPARE_LT || pathkey->pk_nulls_first)
3741 606 : return;
3742 :
3743 : /* If eclass is volatile, no hope of using an indexscan */
3744 1046 : if (pathkey->pk_eclass->ec_has_volatile)
3745 0 : return;
3746 :
3747 : /*
3748 : * Try to match eclass member expression(s) to index. Note that child
3749 : * EC members are considered, but only when they belong to the target
3750 : * relation. (Unlike regular members, the same expression could be a
3751 : * child member of more than one EC. Therefore, the same index could
3752 : * be considered to match more than one pathkey list, which is OK
3753 : * here. See also get_eclass_for_sort_expr.)
3754 : */
3755 1046 : setup_eclass_member_iterator(&it, pathkey->pk_eclass,
3756 1046 : index->rel->relids);
3757 1650 : while ((member = eclass_member_iterator_next(&it)) != NULL)
3758 : {
3759 : int indexcol;
3760 :
3761 : /* No possibility of match if it references other relations */
3762 1078 : if (!bms_equal(member->em_relids, index->rel->relids))
3763 32 : continue;
3764 :
3765 : /*
3766 : * We allow any column of the index to match each pathkey; they
3767 : * don't have to match left-to-right as you might expect. This is
3768 : * correct for GiST, and it doesn't matter for SP-GiST because
3769 : * that doesn't handle multiple columns anyway, and no other
3770 : * existing AMs support amcanorderbyop. We might need different
3771 : * logic in future for other implementations.
3772 : */
3773 1906 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
3774 : {
3775 : Expr *expr;
3776 :
3777 1334 : expr = match_clause_to_ordering_op(index,
3778 : indexcol,
3779 : member->em_expr,
3780 : pathkey->pk_opfamily);
3781 1334 : if (expr)
3782 : {
3783 474 : *orderby_clauses_p = lappend(*orderby_clauses_p, expr);
3784 474 : *clause_columns_p = lappend_int(*clause_columns_p, indexcol);
3785 474 : found = true;
3786 474 : break;
3787 : }
3788 : }
3789 :
3790 1046 : if (found) /* don't want to look at remaining members */
3791 474 : break;
3792 : }
3793 :
3794 : /*
3795 : * Return the matches found so far when this pathkey couldn't be
3796 : * matched to the index.
3797 : */
3798 1046 : if (!found)
3799 572 : return;
3800 : }
3801 : }
3802 :
3803 : /*
3804 : * match_clause_to_ordering_op
3805 : * Determines whether an ordering operator expression matches an
3806 : * index column.
3807 : *
3808 : * This is similar to, but simpler than, match_clause_to_indexcol.
3809 : * We only care about simple OpExpr cases. The input is a bare
3810 : * expression that is being ordered by, which must be of the form
3811 : * (indexkey op const) or (const op indexkey) where op is an ordering
3812 : * operator for the column's opfamily.
3813 : *
3814 : * 'index' is the index of interest.
3815 : * 'indexcol' is a column number of 'index' (counting from 0).
3816 : * 'clause' is the ordering expression to be tested.
3817 : * 'pk_opfamily' is the btree opfamily describing the required sort order.
3818 : *
3819 : * Note that we currently do not consider the collation of the ordering
3820 : * operator's result. In practical cases the result type will be numeric
3821 : * and thus have no collation, and it's not very clear what to match to
3822 : * if it did have a collation. The index's collation should match the
3823 : * ordering operator's input collation, not its result.
3824 : *
3825 : * If successful, return 'clause' as-is if the indexkey is on the left,
3826 : * otherwise a commuted copy of 'clause'. If no match, return NULL.
3827 : */
3828 : static Expr *
3829 1334 : match_clause_to_ordering_op(IndexOptInfo *index,
3830 : int indexcol,
3831 : Expr *clause,
3832 : Oid pk_opfamily)
3833 : {
3834 : Oid opfamily;
3835 : Oid idxcollation;
3836 : Node *leftop,
3837 : *rightop;
3838 : Oid expr_op;
3839 : Oid expr_coll;
3840 : Oid sortfamily;
3841 : bool commuted;
3842 :
3843 : Assert(indexcol < index->nkeycolumns);
3844 :
3845 1334 : opfamily = index->opfamily[indexcol];
3846 1334 : idxcollation = index->indexcollations[indexcol];
3847 :
3848 : /*
3849 : * Clause must be a binary opclause.
3850 : */
3851 1334 : if (!is_opclause(clause))
3852 860 : return NULL;
3853 474 : leftop = get_leftop(clause);
3854 474 : rightop = get_rightop(clause);
3855 474 : if (!leftop || !rightop)
3856 0 : return NULL;
3857 474 : expr_op = ((OpExpr *) clause)->opno;
3858 474 : expr_coll = ((OpExpr *) clause)->inputcollid;
3859 :
3860 : /*
3861 : * We can forget the whole thing right away if wrong collation.
3862 : */
3863 474 : if (!IndexCollMatchesExprColl(idxcollation, expr_coll))
3864 0 : return NULL;
3865 :
3866 : /*
3867 : * Check for clauses of the form: (indexkey operator constant) or
3868 : * (constant operator indexkey).
3869 : */
3870 474 : if (match_index_to_operand(leftop, indexcol, index) &&
3871 450 : !contain_var_clause(rightop) &&
3872 450 : !contain_volatile_functions(rightop))
3873 : {
3874 450 : commuted = false;
3875 : }
3876 24 : else if (match_index_to_operand(rightop, indexcol, index) &&
3877 24 : !contain_var_clause(leftop) &&
3878 24 : !contain_volatile_functions(leftop))
3879 : {
3880 : /* Might match, but we need a commuted operator */
3881 24 : expr_op = get_commutator(expr_op);
3882 24 : if (expr_op == InvalidOid)
3883 0 : return NULL;
3884 24 : commuted = true;
3885 : }
3886 : else
3887 0 : return NULL;
3888 :
3889 : /*
3890 : * Is the (commuted) operator an ordering operator for the opfamily? And
3891 : * if so, does it yield the right sorting semantics?
3892 : */
3893 474 : sortfamily = get_op_opfamily_sortfamily(expr_op, opfamily);
3894 474 : if (sortfamily != pk_opfamily)
3895 0 : return NULL;
3896 :
3897 : /* We have a match. Return clause or a commuted version thereof. */
3898 474 : if (commuted)
3899 : {
3900 24 : OpExpr *newclause = makeNode(OpExpr);
3901 :
3902 : /* flat-copy all the fields of clause */
3903 24 : memcpy(newclause, clause, sizeof(OpExpr));
3904 :
3905 : /* commute it */
3906 24 : newclause->opno = expr_op;
3907 24 : newclause->opfuncid = InvalidOid;
3908 24 : newclause->args = list_make2(rightop, leftop);
3909 :
3910 24 : clause = (Expr *) newclause;
3911 : }
3912 :
3913 474 : return clause;
3914 : }
3915 :
3916 :
3917 : /****************************************************************************
3918 : * ---- ROUTINES TO DO PARTIAL INDEX PREDICATE TESTS ----
3919 : ****************************************************************************/
3920 :
3921 : /*
3922 : * check_index_predicates
3923 : * Set the predicate-derived IndexOptInfo fields for each index
3924 : * of the specified relation.
3925 : *
3926 : * predOK is set true if the index is partial and its predicate is satisfied
3927 : * for this query, ie the query's WHERE clauses imply the predicate.
3928 : *
3929 : * indrestrictinfo is set to the relation's baserestrictinfo list less any
3930 : * conditions that are implied by the index's predicate. (Obviously, for a
3931 : * non-partial index, this is the same as baserestrictinfo.) Such conditions
3932 : * can be dropped from the plan when using the index, in certain cases.
3933 : *
3934 : * At one time it was possible for this to get re-run after adding more
3935 : * restrictions to the rel, thus possibly letting us prove more indexes OK.
3936 : * That doesn't happen any more (at least not in the core code's usage),
3937 : * but this code still supports it in case extensions want to mess with the
3938 : * baserestrictinfo list. We assume that adding more restrictions can't make
3939 : * an index not predOK. We must recompute indrestrictinfo each time, though,
3940 : * to make sure any newly-added restrictions get into it if needed.
3941 : */
3942 : void
3943 417822 : check_index_predicates(PlannerInfo *root, RelOptInfo *rel)
3944 : {
3945 : List *clauselist;
3946 : bool have_partial;
3947 : bool is_target_rel;
3948 : Relids otherrels;
3949 : ListCell *lc;
3950 :
3951 : /* Indexes are available only on base or "other" member relations. */
3952 : Assert(IS_SIMPLE_REL(rel));
3953 :
3954 : /*
3955 : * Initialize the indrestrictinfo lists to be identical to
3956 : * baserestrictinfo, and check whether there are any partial indexes. If
3957 : * not, this is all we need to do.
3958 : */
3959 417822 : have_partial = false;
3960 1152380 : foreach(lc, rel->indexlist)
3961 : {
3962 734558 : IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
3963 :
3964 734558 : index->indrestrictinfo = rel->baserestrictinfo;
3965 734558 : if (index->indpred)
3966 1052 : have_partial = true;
3967 : }
3968 417822 : if (!have_partial)
3969 417094 : return;
3970 :
3971 : /*
3972 : * Construct a list of clauses that we can assume true for the purpose of
3973 : * proving the index(es) usable. Restriction clauses for the rel are
3974 : * always usable, and so are any join clauses that are "movable to" this
3975 : * rel. Also, we can consider any EC-derivable join clauses (which must
3976 : * be "movable to" this rel, by definition).
3977 : */
3978 728 : clauselist = list_copy(rel->baserestrictinfo);
3979 :
3980 : /* Scan the rel's join clauses */
3981 728 : foreach(lc, rel->joininfo)
3982 : {
3983 0 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
3984 :
3985 : /* Check if clause can be moved to this rel */
3986 0 : if (!join_clause_is_movable_to(rinfo, rel))
3987 0 : continue;
3988 :
3989 0 : clauselist = lappend(clauselist, rinfo);
3990 : }
3991 :
3992 : /*
3993 : * Add on any equivalence-derivable join clauses. Computing the correct
3994 : * relid sets for generate_join_implied_equalities is slightly tricky
3995 : * because the rel could be a child rel rather than a true baserel, and in
3996 : * that case we must subtract its parents' relid(s) from all_query_rels.
3997 : * Additionally, we mustn't consider clauses that are only computable
3998 : * after outer joins that can null the rel.
3999 : */
4000 728 : if (rel->reloptkind == RELOPT_OTHER_MEMBER_REL)
4001 72 : otherrels = bms_difference(root->all_query_rels,
4002 72 : find_childrel_parents(root, rel));
4003 : else
4004 656 : otherrels = bms_difference(root->all_query_rels, rel->relids);
4005 728 : otherrels = bms_del_members(otherrels, rel->nulling_relids);
4006 :
4007 728 : if (!bms_is_empty(otherrels))
4008 : clauselist =
4009 98 : list_concat(clauselist,
4010 98 : generate_join_implied_equalities(root,
4011 98 : bms_union(rel->relids,
4012 : otherrels),
4013 : otherrels,
4014 : rel,
4015 : NULL));
4016 :
4017 : /*
4018 : * Normally we remove quals that are implied by a partial index's
4019 : * predicate from indrestrictinfo, indicating that they need not be
4020 : * checked explicitly by an indexscan plan using this index. However, if
4021 : * the rel is a target relation of UPDATE/DELETE/MERGE/SELECT FOR UPDATE,
4022 : * we cannot remove such quals from the plan, because they need to be in
4023 : * the plan so that they will be properly rechecked by EvalPlanQual
4024 : * testing. Some day we might want to remove such quals from the main
4025 : * plan anyway and pass them through to EvalPlanQual via a side channel;
4026 : * but for now, we just don't remove implied quals at all for target
4027 : * relations.
4028 : */
4029 1312 : is_target_rel = (bms_is_member(rel->relid, root->all_result_relids) ||
4030 584 : get_plan_rowmark(root->rowMarks, rel->relid) != NULL);
4031 :
4032 : /*
4033 : * Now try to prove each index predicate true, and compute the
4034 : * indrestrictinfo lists for partial indexes. Note that we compute the
4035 : * indrestrictinfo list even for non-predOK indexes; this might seem
4036 : * wasteful, but we may be able to use such indexes in OR clauses, cf
4037 : * generate_bitmap_or_paths().
4038 : */
4039 2214 : foreach(lc, rel->indexlist)
4040 : {
4041 1486 : IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
4042 : ListCell *lcr;
4043 :
4044 1486 : if (index->indpred == NIL)
4045 434 : continue; /* ignore non-partial indexes here */
4046 :
4047 1052 : if (!index->predOK) /* don't repeat work if already proven OK */
4048 1052 : index->predOK = predicate_implied_by(index->indpred, clauselist,
4049 : false);
4050 :
4051 : /* If rel is an update target, leave indrestrictinfo as set above */
4052 1052 : if (is_target_rel)
4053 204 : continue;
4054 :
4055 : /*
4056 : * If index is !amoptionalkey, also leave indrestrictinfo as set
4057 : * above. Otherwise we risk removing all quals for the first index
4058 : * key and then not being able to generate an indexscan at all. It
4059 : * would be better to be more selective, but we've not yet identified
4060 : * which if any of the quals match the first index key.
4061 : */
4062 848 : if (!index->amoptionalkey)
4063 36 : continue;
4064 :
4065 : /* Else compute indrestrictinfo as the non-implied quals */
4066 812 : index->indrestrictinfo = NIL;
4067 1914 : foreach(lcr, rel->baserestrictinfo)
4068 : {
4069 1102 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lcr);
4070 :
4071 : /* predicate_implied_by() assumes first arg is immutable */
4072 1102 : if (contain_mutable_functions((Node *) rinfo->clause) ||
4073 1102 : !predicate_implied_by(list_make1(rinfo->clause),
4074 : index->indpred, false))
4075 782 : index->indrestrictinfo = lappend(index->indrestrictinfo, rinfo);
4076 : }
4077 : }
4078 : }
4079 :
4080 : /****************************************************************************
4081 : * ---- ROUTINES TO CHECK EXTERNALLY-VISIBLE CONDITIONS ----
4082 : ****************************************************************************/
4083 :
4084 : /*
4085 : * ec_member_matches_indexcol
4086 : * Test whether an EquivalenceClass member matches an index column.
4087 : *
4088 : * This is a callback for use by generate_implied_equalities_for_column.
4089 : */
4090 : static bool
4091 484586 : ec_member_matches_indexcol(PlannerInfo *root, RelOptInfo *rel,
4092 : EquivalenceClass *ec, EquivalenceMember *em,
4093 : void *arg)
4094 : {
4095 484586 : IndexOptInfo *index = ((ec_member_matches_arg *) arg)->index;
4096 484586 : int indexcol = ((ec_member_matches_arg *) arg)->indexcol;
4097 : Oid curFamily;
4098 : Oid curCollation;
4099 :
4100 : Assert(indexcol < index->nkeycolumns);
4101 :
4102 484586 : curFamily = index->opfamily[indexcol];
4103 484586 : curCollation = index->indexcollations[indexcol];
4104 :
4105 : /*
4106 : * If it's a btree index, we can reject it if its opfamily isn't
4107 : * compatible with the EC, since no clause generated from the EC could be
4108 : * used with the index. For non-btree indexes, we can't easily tell
4109 : * whether clauses generated from the EC could be used with the index, so
4110 : * don't check the opfamily. This might mean we return "true" for a
4111 : * useless EC, so we have to recheck the results of
4112 : * generate_implied_equalities_for_column; see
4113 : * match_eclass_clauses_to_index.
4114 : */
4115 484586 : if (index->relam == BTREE_AM_OID &&
4116 484544 : !list_member_oid(ec->ec_opfamilies, curFamily))
4117 156796 : return false;
4118 :
4119 : /* We insist on collation match for all index types, though */
4120 327790 : if (!IndexCollMatchesExprColl(curCollation, ec->ec_collation))
4121 18 : return false;
4122 :
4123 327772 : return match_index_to_operand((Node *) em->em_expr, indexcol, index);
4124 : }
4125 :
4126 : /*
4127 : * relation_has_unique_index_for
4128 : * Determine whether the relation provably has at most one row satisfying
4129 : * a set of equality conditions, because the conditions constrain all
4130 : * columns of some unique index.
4131 : *
4132 : * The conditions are provided as a list of RestrictInfo nodes, where the
4133 : * caller has already determined that each condition is a mergejoinable
4134 : * equality with an expression in this relation on one side, and an
4135 : * expression not involving this relation on the other. The transient
4136 : * outer_is_left flag is used to identify which side we should look at:
4137 : * left side if outer_is_left is false, right side if it is true.
4138 : *
4139 : * The caller need only supply equality conditions arising from joins;
4140 : * this routine automatically adds in any usable baserestrictinfo clauses.
4141 : * (Note that the passed-in restrictlist will be destructively modified!)
4142 : *
4143 : * If extra_clauses isn't NULL, return baserestrictinfo clauses which were used
4144 : * to derive uniqueness.
4145 : */
4146 : bool
4147 222530 : relation_has_unique_index_for(PlannerInfo *root, RelOptInfo *rel,
4148 : List *restrictlist, List **extra_clauses)
4149 : {
4150 : ListCell *ic;
4151 :
4152 : /* Short-circuit if no indexes... */
4153 222530 : if (rel->indexlist == NIL)
4154 0 : return false;
4155 :
4156 : /*
4157 : * Examine the rel's restriction clauses for usable var = const clauses
4158 : * that we can add to the restrictlist.
4159 : */
4160 366936 : foreach(ic, rel->baserestrictinfo)
4161 : {
4162 144406 : RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(ic);
4163 :
4164 : /*
4165 : * Note: can_join won't be set for a restriction clause, but
4166 : * mergeopfamilies will be if it has a mergejoinable operator and
4167 : * doesn't contain volatile functions.
4168 : */
4169 144406 : if (restrictinfo->mergeopfamilies == NIL)
4170 58256 : continue; /* not mergejoinable */
4171 :
4172 : /*
4173 : * The clause certainly doesn't refer to anything but the given rel.
4174 : * If either side is pseudoconstant then we can use it.
4175 : */
4176 86150 : if (bms_is_empty(restrictinfo->left_relids))
4177 : {
4178 : /* righthand side is inner */
4179 62 : restrictinfo->outer_is_left = true;
4180 : }
4181 86088 : else if (bms_is_empty(restrictinfo->right_relids))
4182 : {
4183 : /* lefthand side is inner */
4184 85962 : restrictinfo->outer_is_left = false;
4185 : }
4186 : else
4187 126 : continue;
4188 :
4189 : /* OK, add to list */
4190 86024 : restrictlist = lappend(restrictlist, restrictinfo);
4191 : }
4192 :
4193 : /* Short-circuit the easy case */
4194 222530 : if (restrictlist == NIL)
4195 1120 : return false;
4196 :
4197 : /* Examine each index of the relation ... */
4198 564446 : foreach(ic, rel->indexlist)
4199 : {
4200 469518 : IndexOptInfo *ind = (IndexOptInfo *) lfirst(ic);
4201 : int c;
4202 469518 : List *exprs = NIL;
4203 :
4204 : /*
4205 : * If the index is not unique, or not immediately enforced, or if it's
4206 : * a partial index, it's useless here. We're unable to make use of
4207 : * predOK partial unique indexes due to the fact that
4208 : * check_index_predicates() also makes use of join predicates to
4209 : * determine if the partial index is usable. Here we need proofs that
4210 : * hold true before any joins are evaluated.
4211 : */
4212 469518 : if (!ind->unique || !ind->immediate || ind->indpred != NIL)
4213 128812 : continue;
4214 :
4215 : /*
4216 : * Try to find each index column in the list of conditions. This is
4217 : * O(N^2) or worse, but we expect all the lists to be short.
4218 : */
4219 570096 : for (c = 0; c < ind->nkeycolumns; c++)
4220 : {
4221 : ListCell *lc;
4222 :
4223 864352 : foreach(lc, restrictlist)
4224 : {
4225 650128 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
4226 : Node *rexpr;
4227 :
4228 : /*
4229 : * The condition's equality operator must be a member of the
4230 : * index opfamily, else it is not asserting the right kind of
4231 : * equality behavior for this index. We check this first
4232 : * since it's probably cheaper than match_index_to_operand().
4233 : */
4234 650128 : if (!list_member_oid(rinfo->mergeopfamilies, ind->opfamily[c]))
4235 198948 : continue;
4236 :
4237 : /*
4238 : * XXX at some point we may need to check collations here too.
4239 : * For the moment we assume all collations reduce to the same
4240 : * notion of equality.
4241 : */
4242 :
4243 : /* OK, see if the condition operand matches the index key */
4244 451180 : if (rinfo->outer_is_left)
4245 180868 : rexpr = get_rightop(rinfo->clause);
4246 : else
4247 270312 : rexpr = get_leftop(rinfo->clause);
4248 :
4249 451180 : if (match_index_to_operand(rexpr, c, ind))
4250 : {
4251 229390 : if (bms_membership(rinfo->clause_relids) == BMS_SINGLETON)
4252 : {
4253 : MemoryContext oldMemCtx =
4254 53676 : MemoryContextSwitchTo(root->planner_cxt);
4255 :
4256 : /*
4257 : * Add filter clause into a list allowing caller to
4258 : * know if uniqueness have made not only by join
4259 : * clauses.
4260 : */
4261 : Assert(bms_is_empty(rinfo->left_relids) ||
4262 : bms_is_empty(rinfo->right_relids));
4263 53676 : if (extra_clauses)
4264 144 : exprs = lappend(exprs, rinfo);
4265 53676 : MemoryContextSwitchTo(oldMemCtx);
4266 : }
4267 :
4268 229390 : break; /* found a match; column is unique */
4269 : }
4270 : }
4271 :
4272 443614 : if (lc == NULL)
4273 214224 : break; /* no match; this index doesn't help us */
4274 : }
4275 :
4276 : /* Matched all key columns of this index? */
4277 340706 : if (c == ind->nkeycolumns)
4278 : {
4279 126482 : if (extra_clauses)
4280 654 : *extra_clauses = exprs;
4281 126482 : return true;
4282 : }
4283 : }
4284 :
4285 94928 : return false;
4286 : }
4287 :
4288 : /*
4289 : * indexcol_is_bool_constant_for_query
4290 : *
4291 : * If an index column is constrained to have a constant value by the query's
4292 : * WHERE conditions, then it's irrelevant for sort-order considerations.
4293 : * Usually that means we have a restriction clause WHERE indexcol = constant,
4294 : * which gets turned into an EquivalenceClass containing a constant, which
4295 : * is recognized as redundant by build_index_pathkeys(). But if the index
4296 : * column is a boolean variable (or expression), then we are not going to
4297 : * see WHERE indexcol = constant, because expression preprocessing will have
4298 : * simplified that to "WHERE indexcol" or "WHERE NOT indexcol". So we are not
4299 : * going to have a matching EquivalenceClass (unless the query also contains
4300 : * "ORDER BY indexcol"). To allow such cases to work the same as they would
4301 : * for non-boolean values, this function is provided to detect whether the
4302 : * specified index column matches a boolean restriction clause.
4303 : */
4304 : bool
4305 670404 : indexcol_is_bool_constant_for_query(PlannerInfo *root,
4306 : IndexOptInfo *index,
4307 : int indexcol)
4308 : {
4309 : ListCell *lc;
4310 :
4311 : /* If the index isn't boolean, we can't possibly get a match */
4312 670404 : if (!IsBooleanOpfamily(index->opfamily[indexcol]))
4313 667372 : return false;
4314 :
4315 : /* Check each restriction clause for the index's rel */
4316 3068 : foreach(lc, index->rel->baserestrictinfo)
4317 : {
4318 1292 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
4319 :
4320 : /*
4321 : * As in match_clause_to_indexcol, never match pseudoconstants to
4322 : * indexes. (It might be semantically okay to do so here, but the
4323 : * odds of getting a match are negligible, so don't waste the cycles.)
4324 : */
4325 1292 : if (rinfo->pseudoconstant)
4326 0 : continue;
4327 :
4328 : /* See if we can match the clause's expression to the index column */
4329 1292 : if (match_boolean_index_clause(root, rinfo, indexcol, index))
4330 1256 : return true;
4331 : }
4332 :
4333 1776 : return false;
4334 : }
4335 :
4336 :
4337 : /****************************************************************************
4338 : * ---- ROUTINES TO CHECK OPERANDS ----
4339 : ****************************************************************************/
4340 :
4341 : /*
4342 : * match_index_to_operand()
4343 : * Generalized test for a match between an index's key
4344 : * and the operand on one side of a restriction or join clause.
4345 : *
4346 : * operand: the nodetree to be compared to the index
4347 : * indexcol: the column number of the index (counting from 0)
4348 : * index: the index of interest
4349 : *
4350 : * Note that we aren't interested in collations here; the caller must check
4351 : * for a collation match, if it's dealing with an operator where that matters.
4352 : *
4353 : * This is exported for use in selfuncs.c.
4354 : */
4355 : bool
4356 3792686 : match_index_to_operand(Node *operand,
4357 : int indexcol,
4358 : IndexOptInfo *index)
4359 : {
4360 : int indkey;
4361 :
4362 : /*
4363 : * Ignore any PlaceHolderVar node contained in the operand. This is
4364 : * needed to be able to apply indexscanning in cases where the operand (or
4365 : * a subtree) has been wrapped in PlaceHolderVars to enforce separate
4366 : * identity or as a result of outer joins.
4367 : */
4368 3792686 : operand = strip_phvs_in_index_operand(operand);
4369 :
4370 : /*
4371 : * Ignore any RelabelType node above the operand. This is needed to be
4372 : * able to apply indexscanning in binary-compatible-operator cases.
4373 : *
4374 : * Note: we must handle nested RelabelType nodes here. While
4375 : * eval_const_expressions() will have simplified them to at most one
4376 : * layer, our prior stripping of PlaceHolderVars may have brought separate
4377 : * RelabelTypes into adjacency.
4378 : */
4379 3816534 : while (operand && IsA(operand, RelabelType))
4380 23848 : operand = (Node *) ((RelabelType *) operand)->arg;
4381 :
4382 3792686 : indkey = index->indexkeys[indexcol];
4383 3792686 : if (indkey != 0)
4384 : {
4385 : /*
4386 : * Simple index column; operand must be a matching Var.
4387 : */
4388 3786592 : if (operand && IsA(operand, Var) &&
4389 2821790 : index->rel->relid == ((Var *) operand)->varno &&
4390 2621754 : indkey == ((Var *) operand)->varattno &&
4391 931270 : ((Var *) operand)->varnullingrels == NULL)
4392 929640 : return true;
4393 : }
4394 : else
4395 : {
4396 : /*
4397 : * Index expression; find the correct expression. (This search could
4398 : * be avoided, at the cost of complicating all the callers of this
4399 : * routine; doesn't seem worth it.)
4400 : */
4401 : ListCell *indexpr_item;
4402 : int i;
4403 : Node *indexkey;
4404 :
4405 6094 : indexpr_item = list_head(index->indexprs);
4406 6094 : for (i = 0; i < indexcol; i++)
4407 : {
4408 0 : if (index->indexkeys[i] == 0)
4409 : {
4410 0 : if (indexpr_item == NULL)
4411 0 : elog(ERROR, "wrong number of index expressions");
4412 0 : indexpr_item = lnext(index->indexprs, indexpr_item);
4413 : }
4414 : }
4415 6094 : if (indexpr_item == NULL)
4416 0 : elog(ERROR, "wrong number of index expressions");
4417 6094 : indexkey = (Node *) lfirst(indexpr_item);
4418 :
4419 : /*
4420 : * Does it match the operand? Again, strip any relabeling.
4421 : */
4422 6094 : if (indexkey && IsA(indexkey, RelabelType))
4423 10 : indexkey = (Node *) ((RelabelType *) indexkey)->arg;
4424 :
4425 6094 : if (equal(indexkey, operand))
4426 2176 : return true;
4427 : }
4428 :
4429 2860870 : return false;
4430 : }
4431 :
4432 : /*
4433 : * strip_phvs_in_index_operand
4434 : * Strip PlaceHolderVar nodes from the given operand expression to
4435 : * facilitate matching against an index's key.
4436 : *
4437 : * A PlaceHolderVar appearing in a relation-scan-level expression is
4438 : * effectively a no-op. Nevertheless, to play it safe, we strip only
4439 : * PlaceHolderVars that are not marked nullable.
4440 : *
4441 : * The removal is performed recursively because PlaceHolderVars can be nested
4442 : * or interleaved with other node types. We must peel back all layers to
4443 : * expose the base operand.
4444 : *
4445 : * As a performance optimization, we first use a lightweight walker to check
4446 : * for the presence of strippable PlaceHolderVars. The expensive mutator is
4447 : * invoked only if a candidate is found, avoiding unnecessary memory allocation
4448 : * and tree copying in the common case where no PlaceHolderVars are present.
4449 : */
4450 : Node *
4451 4000156 : strip_phvs_in_index_operand(Node *operand)
4452 : {
4453 : /* Don't mutate/copy if no target PHVs exist */
4454 4000156 : if (!contain_strippable_phv_walker(operand, NULL))
4455 3999068 : return operand;
4456 :
4457 1088 : return strip_phvs_in_index_operand_mutator(operand, NULL);
4458 : }
4459 :
4460 : /*
4461 : * contain_strippable_phv_walker
4462 : * Detect if there are any PlaceHolderVars in the tree that are candidates
4463 : * for stripping.
4464 : *
4465 : * We identify a PlaceHolderVar as strippable only if its phnullingrels is
4466 : * empty.
4467 : */
4468 : static bool
4469 4097966 : contain_strippable_phv_walker(Node *node, void *context)
4470 : {
4471 4097966 : if (node == NULL)
4472 8044 : return false;
4473 :
4474 4089922 : if (IsA(node, PlaceHolderVar))
4475 : {
4476 1178 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
4477 :
4478 1178 : if (bms_is_empty(phv->phnullingrels))
4479 1088 : return true;
4480 : }
4481 :
4482 4088834 : return expression_tree_walker(node, contain_strippable_phv_walker,
4483 : context);
4484 : }
4485 :
4486 : /*
4487 : * strip_phvs_in_index_operand_mutator
4488 : * Recursively remove PlaceHolderVars in the tree that match the criteria.
4489 : *
4490 : * We strip a PlaceHolderVar only if its phnullingrels is empty, replacing it
4491 : * with its contained expression.
4492 : */
4493 : static Node *
4494 3244 : strip_phvs_in_index_operand_mutator(Node *node, void *context)
4495 : {
4496 3244 : if (node == NULL)
4497 0 : return NULL;
4498 :
4499 3244 : if (IsA(node, PlaceHolderVar))
4500 : {
4501 1088 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
4502 :
4503 : /* If matches the criteria, strip it */
4504 1088 : if (bms_is_empty(phv->phnullingrels))
4505 : {
4506 : /* Recurse on its contained expression */
4507 1088 : return strip_phvs_in_index_operand_mutator((Node *) phv->phexpr,
4508 : context);
4509 : }
4510 :
4511 : /* Otherwise, keep this PHV but check its contained expression */
4512 : }
4513 :
4514 2156 : return expression_tree_mutator(node, strip_phvs_in_index_operand_mutator,
4515 : context);
4516 : }
4517 :
4518 : /*
4519 : * is_pseudo_constant_for_index()
4520 : * Test whether the given expression can be used as an indexscan
4521 : * comparison value.
4522 : *
4523 : * An indexscan comparison value must not contain any volatile functions,
4524 : * and it can't contain any Vars of the index's own table. Vars of
4525 : * other tables are okay, though; in that case we'd be producing an
4526 : * indexqual usable in a parameterized indexscan. This is, therefore,
4527 : * a weaker condition than is_pseudo_constant_clause().
4528 : *
4529 : * This function is exported for use by planner support functions,
4530 : * which will have available the IndexOptInfo, but not any RestrictInfo
4531 : * infrastructure. It is making the same test made by functions above
4532 : * such as match_opclause_to_indexcol(), but those rely where possible
4533 : * on RestrictInfo information about variable membership.
4534 : *
4535 : * expr: the nodetree to be checked
4536 : * index: the index of interest
4537 : */
4538 : bool
4539 0 : is_pseudo_constant_for_index(PlannerInfo *root, Node *expr, IndexOptInfo *index)
4540 : {
4541 : /* pull_varnos is cheaper than volatility check, so do that first */
4542 0 : if (bms_is_member(index->rel->relid, pull_varnos(root, expr)))
4543 0 : return false; /* no good, contains Var of table */
4544 0 : if (contain_volatile_functions(expr))
4545 0 : return false; /* no good, volatile comparison value */
4546 0 : return true;
4547 : }
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