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 "access/stratnum.h"
19 : #include "access/sysattr.h"
20 : #include "access/transam.h"
21 : #include "catalog/pg_am.h"
22 : #include "catalog/pg_amop.h"
23 : #include "catalog/pg_operator.h"
24 : #include "catalog/pg_opfamily.h"
25 : #include "catalog/pg_type.h"
26 : #include "nodes/makefuncs.h"
27 : #include "nodes/nodeFuncs.h"
28 : #include "nodes/supportnodes.h"
29 : #include "optimizer/cost.h"
30 : #include "optimizer/optimizer.h"
31 : #include "optimizer/pathnode.h"
32 : #include "optimizer/paths.h"
33 : #include "optimizer/placeholder.h"
34 : #include "optimizer/prep.h"
35 : #include "optimizer/restrictinfo.h"
36 : #include "utils/lsyscache.h"
37 : #include "utils/selfuncs.h"
38 :
39 :
40 : /* XXX see PartCollMatchesExprColl */
41 : #define IndexCollMatchesExprColl(idxcollation, exprcollation) \
42 : ((idxcollation) == InvalidOid || (idxcollation) == (exprcollation))
43 :
44 : /* Whether we are looking for plain indexscan, bitmap scan, or either */
45 : typedef enum
46 : {
47 : ST_INDEXSCAN, /* must support amgettuple */
48 : ST_BITMAPSCAN, /* must support amgetbitmap */
49 : ST_ANYSCAN, /* either is okay */
50 : } ScanTypeControl;
51 :
52 : /* Data structure for collecting qual clauses that match an index */
53 : typedef struct
54 : {
55 : bool nonempty; /* True if lists are not all empty */
56 : /* Lists of IndexClause nodes, one list per index column */
57 : List *indexclauses[INDEX_MAX_KEYS];
58 : } IndexClauseSet;
59 :
60 : /* Per-path data used within choose_bitmap_and() */
61 : typedef struct
62 : {
63 : Path *path; /* IndexPath, BitmapAndPath, or BitmapOrPath */
64 : List *quals; /* the WHERE clauses it uses */
65 : List *preds; /* predicates of its partial index(es) */
66 : Bitmapset *clauseids; /* quals+preds represented as a bitmapset */
67 : bool unclassifiable; /* has too many quals+preds to process? */
68 : } PathClauseUsage;
69 :
70 : /* Callback argument for ec_member_matches_indexcol */
71 : typedef struct
72 : {
73 : IndexOptInfo *index; /* index we're considering */
74 : int indexcol; /* index column we want to match to */
75 : } ec_member_matches_arg;
76 :
77 :
78 : static void consider_index_join_clauses(PlannerInfo *root, RelOptInfo *rel,
79 : IndexOptInfo *index,
80 : IndexClauseSet *rclauseset,
81 : IndexClauseSet *jclauseset,
82 : IndexClauseSet *eclauseset,
83 : List **bitindexpaths);
84 : static void consider_index_join_outer_rels(PlannerInfo *root, RelOptInfo *rel,
85 : IndexOptInfo *index,
86 : IndexClauseSet *rclauseset,
87 : IndexClauseSet *jclauseset,
88 : IndexClauseSet *eclauseset,
89 : List **bitindexpaths,
90 : List *indexjoinclauses,
91 : int considered_clauses,
92 : List **considered_relids);
93 : static void get_join_index_paths(PlannerInfo *root, RelOptInfo *rel,
94 : IndexOptInfo *index,
95 : IndexClauseSet *rclauseset,
96 : IndexClauseSet *jclauseset,
97 : IndexClauseSet *eclauseset,
98 : List **bitindexpaths,
99 : Relids relids,
100 : List **considered_relids);
101 : static bool eclass_already_used(EquivalenceClass *parent_ec, Relids oldrelids,
102 : List *indexjoinclauses);
103 : static void get_index_paths(PlannerInfo *root, RelOptInfo *rel,
104 : IndexOptInfo *index, IndexClauseSet *clauses,
105 : List **bitindexpaths);
106 : static List *build_index_paths(PlannerInfo *root, RelOptInfo *rel,
107 : IndexOptInfo *index, IndexClauseSet *clauses,
108 : bool useful_predicate,
109 : ScanTypeControl scantype,
110 : bool *skip_nonnative_saop);
111 : static List *build_paths_for_OR(PlannerInfo *root, RelOptInfo *rel,
112 : List *clauses, List *other_clauses);
113 : static List *generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel,
114 : List *clauses, List *other_clauses);
115 : static Path *choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel,
116 : List *paths);
117 : static int path_usage_comparator(const void *a, const void *b);
118 : static Cost bitmap_scan_cost_est(PlannerInfo *root, RelOptInfo *rel,
119 : Path *ipath);
120 : static Cost bitmap_and_cost_est(PlannerInfo *root, RelOptInfo *rel,
121 : List *paths);
122 : static PathClauseUsage *classify_index_clause_usage(Path *path,
123 : List **clauselist);
124 : static void find_indexpath_quals(Path *bitmapqual, List **quals, List **preds);
125 : static int find_list_position(Node *node, List **nodelist);
126 : static bool check_index_only(RelOptInfo *rel, IndexOptInfo *index);
127 : static double get_loop_count(PlannerInfo *root, Index cur_relid, Relids outer_relids);
128 : static double adjust_rowcount_for_semijoins(PlannerInfo *root,
129 : Index cur_relid,
130 : Index outer_relid,
131 : double rowcount);
132 : static double approximate_joinrel_size(PlannerInfo *root, Relids relids);
133 : static void match_restriction_clauses_to_index(PlannerInfo *root,
134 : IndexOptInfo *index,
135 : IndexClauseSet *clauseset);
136 : static void match_join_clauses_to_index(PlannerInfo *root,
137 : RelOptInfo *rel, IndexOptInfo *index,
138 : IndexClauseSet *clauseset,
139 : List **joinorclauses);
140 : static void match_eclass_clauses_to_index(PlannerInfo *root,
141 : IndexOptInfo *index,
142 : IndexClauseSet *clauseset);
143 : static void match_clauses_to_index(PlannerInfo *root,
144 : List *clauses,
145 : IndexOptInfo *index,
146 : IndexClauseSet *clauseset);
147 : static void match_clause_to_index(PlannerInfo *root,
148 : RestrictInfo *rinfo,
149 : IndexOptInfo *index,
150 : IndexClauseSet *clauseset);
151 : static IndexClause *match_clause_to_indexcol(PlannerInfo *root,
152 : RestrictInfo *rinfo,
153 : int indexcol,
154 : IndexOptInfo *index);
155 : static bool IsBooleanOpfamily(Oid opfamily);
156 : static IndexClause *match_boolean_index_clause(PlannerInfo *root,
157 : RestrictInfo *rinfo,
158 : int indexcol, IndexOptInfo *index);
159 : static IndexClause *match_opclause_to_indexcol(PlannerInfo *root,
160 : RestrictInfo *rinfo,
161 : int indexcol,
162 : IndexOptInfo *index);
163 : static IndexClause *match_funcclause_to_indexcol(PlannerInfo *root,
164 : RestrictInfo *rinfo,
165 : int indexcol,
166 : IndexOptInfo *index);
167 : static IndexClause *get_index_clause_from_support(PlannerInfo *root,
168 : RestrictInfo *rinfo,
169 : Oid funcid,
170 : int indexarg,
171 : int indexcol,
172 : IndexOptInfo *index);
173 : static IndexClause *match_saopclause_to_indexcol(PlannerInfo *root,
174 : RestrictInfo *rinfo,
175 : int indexcol,
176 : IndexOptInfo *index);
177 : static IndexClause *match_rowcompare_to_indexcol(PlannerInfo *root,
178 : RestrictInfo *rinfo,
179 : int indexcol,
180 : IndexOptInfo *index);
181 : static IndexClause *match_orclause_to_indexcol(PlannerInfo *root,
182 : RestrictInfo *rinfo,
183 : int indexcol,
184 : IndexOptInfo *index);
185 : static IndexClause *expand_indexqual_rowcompare(PlannerInfo *root,
186 : RestrictInfo *rinfo,
187 : int indexcol,
188 : IndexOptInfo *index,
189 : Oid expr_op,
190 : bool var_on_left);
191 : static void match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys,
192 : List **orderby_clauses_p,
193 : List **clause_columns_p);
194 : static Expr *match_clause_to_ordering_op(IndexOptInfo *index,
195 : int indexcol, Expr *clause, Oid pk_opfamily);
196 : static bool ec_member_matches_indexcol(PlannerInfo *root, RelOptInfo *rel,
197 : EquivalenceClass *ec, EquivalenceMember *em,
198 : void *arg);
199 :
200 :
201 : /*
202 : * create_index_paths()
203 : * Generate all interesting index paths for the given relation.
204 : * Candidate paths are added to the rel's pathlist (using add_path).
205 : *
206 : * To be considered for an index scan, an index must match one or more
207 : * restriction clauses or join clauses from the query's qual condition,
208 : * or match the query's ORDER BY condition, or have a predicate that
209 : * matches the query's qual condition.
210 : *
211 : * There are two basic kinds of index scans. A "plain" index scan uses
212 : * only restriction clauses (possibly none at all) in its indexqual,
213 : * so it can be applied in any context. A "parameterized" index scan uses
214 : * join clauses (plus restriction clauses, if available) in its indexqual.
215 : * When joining such a scan to one of the relations supplying the other
216 : * variables used in its indexqual, the parameterized scan must appear as
217 : * the inner relation of a nestloop join; it can't be used on the outer side,
218 : * nor in a merge or hash join. In that context, values for the other rels'
219 : * attributes are available and fixed during any one scan of the indexpath.
220 : *
221 : * An IndexPath is generated and submitted to add_path() for each plain or
222 : * parameterized index scan this routine deems potentially interesting for
223 : * the current query.
224 : *
225 : * 'rel' is the relation for which we want to generate index paths
226 : *
227 : * Note: check_index_predicates() must have been run previously for this rel.
228 : *
229 : * Note: in cases involving LATERAL references in the relation's tlist, it's
230 : * possible that rel->lateral_relids is nonempty. Currently, we include
231 : * lateral_relids into the parameterization reported for each path, but don't
232 : * take it into account otherwise. The fact that any such rels *must* be
233 : * available as parameter sources perhaps should influence our choices of
234 : * index quals ... but for now, it doesn't seem worth troubling over.
235 : * In particular, comments below about "unparameterized" paths should be read
236 : * as meaning "unparameterized so far as the indexquals are concerned".
237 : */
238 : void
239 321449 : create_index_paths(PlannerInfo *root, RelOptInfo *rel)
240 : {
241 : List *indexpaths;
242 : List *bitindexpaths;
243 : List *bitjoinpaths;
244 : List *joinorclauses;
245 : IndexClauseSet rclauseset;
246 : IndexClauseSet jclauseset;
247 : IndexClauseSet eclauseset;
248 : ListCell *lc;
249 :
250 : /* Skip the whole mess if no indexes */
251 321449 : if (rel->indexlist == NIL)
252 61151 : return;
253 :
254 : /* Bitmap paths are collected and then dealt with at the end */
255 260298 : bitindexpaths = bitjoinpaths = joinorclauses = NIL;
256 :
257 : /* Examine each index in turn */
258 822970 : foreach(lc, rel->indexlist)
259 : {
260 562672 : IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
261 :
262 : /* Protect limited-size array in IndexClauseSets */
263 : Assert(index->nkeycolumns <= INDEX_MAX_KEYS);
264 :
265 : /*
266 : * Ignore partial indexes that do not match the query.
267 : * (generate_bitmap_or_paths() might be able to do something with
268 : * them, but that's of no concern here.)
269 : */
270 562672 : if (index->indpred != NIL && !index->predOK)
271 459 : continue;
272 :
273 : /*
274 : * Identify the restriction clauses that can match the index.
275 : */
276 19115242 : MemSet(&rclauseset, 0, sizeof(rclauseset));
277 562213 : match_restriction_clauses_to_index(root, index, &rclauseset);
278 :
279 : /*
280 : * Build index paths from the restriction clauses. These will be
281 : * non-parameterized paths. Plain paths go directly to add_path(),
282 : * bitmap paths are added to bitindexpaths to be handled below.
283 : */
284 562213 : get_index_paths(root, rel, index, &rclauseset,
285 : &bitindexpaths);
286 :
287 : /*
288 : * Identify the join clauses that can match the index. For the moment
289 : * we keep them separate from the restriction clauses. Note that this
290 : * step finds only "loose" join clauses that have not been merged into
291 : * EquivalenceClasses. Also, collect join OR clauses for later.
292 : */
293 19115242 : MemSet(&jclauseset, 0, sizeof(jclauseset));
294 562213 : match_join_clauses_to_index(root, rel, index,
295 : &jclauseset, &joinorclauses);
296 :
297 : /*
298 : * Look for EquivalenceClasses that can generate joinclauses matching
299 : * the index.
300 : */
301 19115242 : MemSet(&eclauseset, 0, sizeof(eclauseset));
302 562213 : match_eclass_clauses_to_index(root, index,
303 : &eclauseset);
304 :
305 : /*
306 : * If we found any plain or eclass join clauses, build parameterized
307 : * index paths using them.
308 : */
309 562213 : if (jclauseset.nonempty || eclauseset.nonempty)
310 123601 : consider_index_join_clauses(root, rel, index,
311 : &rclauseset,
312 : &jclauseset,
313 : &eclauseset,
314 : &bitjoinpaths);
315 : }
316 :
317 : /*
318 : * Generate BitmapOrPaths for any suitable OR-clauses present in the
319 : * restriction list. Add these to bitindexpaths.
320 : */
321 260298 : indexpaths = generate_bitmap_or_paths(root, rel,
322 : rel->baserestrictinfo, NIL);
323 260298 : bitindexpaths = list_concat(bitindexpaths, indexpaths);
324 :
325 : /*
326 : * Likewise, generate BitmapOrPaths for any suitable OR-clauses present in
327 : * the joinclause list. Add these to bitjoinpaths.
328 : */
329 260298 : indexpaths = generate_bitmap_or_paths(root, rel,
330 : joinorclauses, rel->baserestrictinfo);
331 260298 : bitjoinpaths = list_concat(bitjoinpaths, indexpaths);
332 :
333 : /*
334 : * If we found anything usable, generate a BitmapHeapPath for the most
335 : * promising combination of restriction bitmap index paths. Note there
336 : * will be only one such path no matter how many indexes exist. This
337 : * should be sufficient since there's basically only one figure of merit
338 : * (total cost) for such a path.
339 : */
340 260298 : if (bitindexpaths != NIL)
341 : {
342 : Path *bitmapqual;
343 : BitmapHeapPath *bpath;
344 :
345 152538 : bitmapqual = choose_bitmap_and(root, rel, bitindexpaths);
346 152538 : bpath = create_bitmap_heap_path(root, rel, bitmapqual,
347 : rel->lateral_relids, 1.0, 0);
348 152538 : add_path(rel, (Path *) bpath);
349 :
350 : /* create a partial bitmap heap path */
351 152538 : if (rel->consider_parallel && rel->lateral_relids == NULL)
352 110741 : create_partial_bitmap_paths(root, rel, bitmapqual);
353 : }
354 :
355 : /*
356 : * Likewise, if we found anything usable, generate BitmapHeapPaths for the
357 : * most promising combinations of join bitmap index paths. Our strategy
358 : * is to generate one such path for each distinct parameterization seen
359 : * among the available bitmap index paths. This may look pretty
360 : * expensive, but usually there won't be very many distinct
361 : * parameterizations. (This logic is quite similar to that in
362 : * consider_index_join_clauses, but we're working with whole paths not
363 : * individual clauses.)
364 : */
365 260298 : if (bitjoinpaths != NIL)
366 : {
367 : List *all_path_outers;
368 :
369 : /* Identify each distinct parameterization seen in bitjoinpaths */
370 107942 : all_path_outers = NIL;
371 243245 : foreach(lc, bitjoinpaths)
372 : {
373 135303 : Path *path = (Path *) lfirst(lc);
374 135303 : Relids required_outer = PATH_REQ_OUTER(path);
375 :
376 135303 : all_path_outers = list_append_unique(all_path_outers,
377 : required_outer);
378 : }
379 :
380 : /* Now, for each distinct parameterization set ... */
381 232452 : foreach(lc, all_path_outers)
382 : {
383 124510 : Relids max_outers = (Relids) lfirst(lc);
384 : List *this_path_set;
385 : Path *bitmapqual;
386 : Relids required_outer;
387 : double loop_count;
388 : BitmapHeapPath *bpath;
389 : ListCell *lcp;
390 :
391 : /* Identify all the bitmap join paths needing no more than that */
392 124510 : this_path_set = NIL;
393 305333 : foreach(lcp, bitjoinpaths)
394 : {
395 180823 : Path *path = (Path *) lfirst(lcp);
396 :
397 180823 : if (bms_is_subset(PATH_REQ_OUTER(path), max_outers))
398 141591 : this_path_set = lappend(this_path_set, path);
399 : }
400 :
401 : /*
402 : * Add in restriction bitmap paths, since they can be used
403 : * together with any join paths.
404 : */
405 124510 : this_path_set = list_concat(this_path_set, bitindexpaths);
406 :
407 : /* Select best AND combination for this parameterization */
408 124510 : bitmapqual = choose_bitmap_and(root, rel, this_path_set);
409 :
410 : /* And push that path into the mix */
411 124510 : required_outer = PATH_REQ_OUTER(bitmapqual);
412 124510 : loop_count = get_loop_count(root, rel->relid, required_outer);
413 124510 : bpath = create_bitmap_heap_path(root, rel, bitmapqual,
414 : required_outer, loop_count, 0);
415 124510 : add_path(rel, (Path *) bpath);
416 : }
417 : }
418 : }
419 :
420 : /*
421 : * consider_index_join_clauses
422 : * Given sets of join clauses for an index, decide which parameterized
423 : * index paths to build.
424 : *
425 : * Plain indexpaths are sent directly to add_path, while potential
426 : * bitmap indexpaths are added to *bitindexpaths for later processing.
427 : *
428 : * 'rel' is the index's heap relation
429 : * 'index' is the index for which we want to generate paths
430 : * 'rclauseset' is the collection of indexable restriction clauses
431 : * 'jclauseset' is the collection of indexable simple join clauses
432 : * 'eclauseset' is the collection of indexable clauses from EquivalenceClasses
433 : * '*bitindexpaths' is the list to add bitmap paths to
434 : */
435 : static void
436 123601 : consider_index_join_clauses(PlannerInfo *root, RelOptInfo *rel,
437 : IndexOptInfo *index,
438 : IndexClauseSet *rclauseset,
439 : IndexClauseSet *jclauseset,
440 : IndexClauseSet *eclauseset,
441 : List **bitindexpaths)
442 : {
443 123601 : int considered_clauses = 0;
444 123601 : List *considered_relids = NIL;
445 : int indexcol;
446 :
447 : /*
448 : * The strategy here is to identify every potentially useful set of outer
449 : * rels that can provide indexable join clauses. For each such set,
450 : * select all the join clauses available from those outer rels, add on all
451 : * the indexable restriction clauses, and generate plain and/or bitmap
452 : * index paths for that set of clauses. This is based on the assumption
453 : * that it's always better to apply a clause as an indexqual than as a
454 : * filter (qpqual); which is where an available clause would end up being
455 : * applied if we omit it from the indexquals.
456 : *
457 : * This looks expensive, but in most practical cases there won't be very
458 : * many distinct sets of outer rels to consider. As a safety valve when
459 : * that's not true, we use a heuristic: limit the number of outer rel sets
460 : * considered to a multiple of the number of clauses considered. (We'll
461 : * always consider using each individual join clause, though.)
462 : *
463 : * For simplicity in selecting relevant clauses, we represent each set of
464 : * outer rels as a maximum set of clause_relids --- that is, the indexed
465 : * relation itself is also included in the relids set. considered_relids
466 : * lists all relids sets we've already tried.
467 : */
468 309697 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
469 : {
470 : /* Consider each applicable simple join clause */
471 186096 : considered_clauses += list_length(jclauseset->indexclauses[indexcol]);
472 186096 : consider_index_join_outer_rels(root, rel, index,
473 : rclauseset, jclauseset, eclauseset,
474 : bitindexpaths,
475 : jclauseset->indexclauses[indexcol],
476 : considered_clauses,
477 : &considered_relids);
478 : /* Consider each applicable eclass join clause */
479 186096 : considered_clauses += list_length(eclauseset->indexclauses[indexcol]);
480 186096 : consider_index_join_outer_rels(root, rel, index,
481 : rclauseset, jclauseset, eclauseset,
482 : bitindexpaths,
483 : eclauseset->indexclauses[indexcol],
484 : considered_clauses,
485 : &considered_relids);
486 : }
487 123601 : }
488 :
489 : /*
490 : * consider_index_join_outer_rels
491 : * Generate parameterized paths based on clause relids in the clause list.
492 : *
493 : * Workhorse for consider_index_join_clauses; see notes therein for rationale.
494 : *
495 : * 'rel', 'index', 'rclauseset', 'jclauseset', 'eclauseset', and
496 : * 'bitindexpaths' as above
497 : * 'indexjoinclauses' is a list of IndexClauses for join clauses
498 : * 'considered_clauses' is the total number of clauses considered (so far)
499 : * '*considered_relids' is a list of all relids sets already considered
500 : */
501 : static void
502 372192 : consider_index_join_outer_rels(PlannerInfo *root, RelOptInfo *rel,
503 : IndexOptInfo *index,
504 : IndexClauseSet *rclauseset,
505 : IndexClauseSet *jclauseset,
506 : IndexClauseSet *eclauseset,
507 : List **bitindexpaths,
508 : List *indexjoinclauses,
509 : int considered_clauses,
510 : List **considered_relids)
511 : {
512 : ListCell *lc;
513 :
514 : /* Examine relids of each joinclause in the given list */
515 510245 : foreach(lc, indexjoinclauses)
516 : {
517 138053 : IndexClause *iclause = (IndexClause *) lfirst(lc);
518 138053 : Relids clause_relids = iclause->rinfo->clause_relids;
519 138053 : EquivalenceClass *parent_ec = iclause->rinfo->parent_ec;
520 : int num_considered_relids;
521 :
522 : /* If we already tried its relids set, no need to do so again */
523 138053 : if (list_member(*considered_relids, clause_relids))
524 5858 : continue;
525 :
526 : /*
527 : * Generate the union of this clause's relids set with each
528 : * previously-tried set. This ensures we try this clause along with
529 : * every interesting subset of previous clauses. However, to avoid
530 : * exponential growth of planning time when there are many clauses,
531 : * limit the number of relid sets accepted to 10 * considered_clauses.
532 : *
533 : * Note: get_join_index_paths appends entries to *considered_relids,
534 : * but we do not need to visit such newly-added entries within this
535 : * loop, so we don't use foreach() here. No real harm would be done
536 : * if we did visit them, since the subset check would reject them; but
537 : * it would waste some cycles.
538 : */
539 132195 : num_considered_relids = list_length(*considered_relids);
540 141159 : for (int pos = 0; pos < num_considered_relids; pos++)
541 : {
542 8964 : Relids oldrelids = (Relids) list_nth(*considered_relids, pos);
543 :
544 : /*
545 : * If either is a subset of the other, no new set is possible.
546 : * This isn't a complete test for redundancy, but it's easy and
547 : * cheap. get_join_index_paths will check more carefully if we
548 : * already generated the same relids set.
549 : */
550 8964 : if (bms_subset_compare(clause_relids, oldrelids) != BMS_DIFFERENT)
551 20 : continue;
552 :
553 : /*
554 : * If this clause was derived from an equivalence class, the
555 : * clause list may contain other clauses derived from the same
556 : * eclass. We should not consider that combining this clause with
557 : * one of those clauses generates a usefully different
558 : * parameterization; so skip if any clause derived from the same
559 : * eclass would already have been included when using oldrelids.
560 : */
561 17759 : if (parent_ec &&
562 8815 : eclass_already_used(parent_ec, oldrelids,
563 : indexjoinclauses))
564 5852 : continue;
565 :
566 : /*
567 : * If the number of relid sets considered exceeds our heuristic
568 : * limit, stop considering combinations of clauses. We'll still
569 : * consider the current clause alone, though (below this loop).
570 : */
571 3092 : if (list_length(*considered_relids) >= 10 * considered_clauses)
572 0 : break;
573 :
574 : /* OK, try the union set */
575 3092 : get_join_index_paths(root, rel, index,
576 : rclauseset, jclauseset, eclauseset,
577 : bitindexpaths,
578 : bms_union(clause_relids, oldrelids),
579 : considered_relids);
580 : }
581 :
582 : /* Also try this set of relids by itself */
583 132195 : get_join_index_paths(root, rel, index,
584 : rclauseset, jclauseset, eclauseset,
585 : bitindexpaths,
586 : clause_relids,
587 : considered_relids);
588 : }
589 372192 : }
590 :
591 : /*
592 : * get_join_index_paths
593 : * Generate index paths using clauses from the specified outer relations.
594 : * In addition to generating paths, relids is added to *considered_relids
595 : * if not already present.
596 : *
597 : * Workhorse for consider_index_join_clauses; see notes therein for rationale.
598 : *
599 : * 'rel', 'index', 'rclauseset', 'jclauseset', 'eclauseset',
600 : * 'bitindexpaths', 'considered_relids' as above
601 : * 'relids' is the current set of relids to consider (the target rel plus
602 : * one or more outer rels)
603 : */
604 : static void
605 135287 : get_join_index_paths(PlannerInfo *root, RelOptInfo *rel,
606 : IndexOptInfo *index,
607 : IndexClauseSet *rclauseset,
608 : IndexClauseSet *jclauseset,
609 : IndexClauseSet *eclauseset,
610 : List **bitindexpaths,
611 : Relids relids,
612 : List **considered_relids)
613 : {
614 : IndexClauseSet clauseset;
615 : int indexcol;
616 :
617 : /* If we already considered this relids set, don't repeat the work */
618 135287 : if (list_member(*considered_relids, relids))
619 0 : return;
620 :
621 : /* Identify indexclauses usable with this relids set */
622 4599758 : MemSet(&clauseset, 0, sizeof(clauseset));
623 :
624 343651 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
625 : {
626 : ListCell *lc;
627 :
628 : /* First find applicable simple join clauses */
629 239627 : foreach(lc, jclauseset->indexclauses[indexcol])
630 : {
631 31263 : IndexClause *iclause = (IndexClause *) lfirst(lc);
632 :
633 31263 : if (bms_is_subset(iclause->rinfo->clause_relids, relids))
634 30946 : clauseset.indexclauses[indexcol] =
635 30946 : lappend(clauseset.indexclauses[indexcol], iclause);
636 : }
637 :
638 : /*
639 : * Add applicable eclass join clauses. The clauses generated for each
640 : * column are redundant (cf generate_implied_equalities_for_column),
641 : * so we need at most one. This is the only exception to the general
642 : * rule of using all available index clauses.
643 : */
644 221984 : foreach(lc, eclauseset->indexclauses[indexcol])
645 : {
646 126816 : IndexClause *iclause = (IndexClause *) lfirst(lc);
647 :
648 126816 : if (bms_is_subset(iclause->rinfo->clause_relids, relids))
649 : {
650 113196 : clauseset.indexclauses[indexcol] =
651 113196 : lappend(clauseset.indexclauses[indexcol], iclause);
652 113196 : break;
653 : }
654 : }
655 :
656 : /* Add restriction clauses */
657 208364 : clauseset.indexclauses[indexcol] =
658 208364 : list_concat(clauseset.indexclauses[indexcol],
659 208364 : rclauseset->indexclauses[indexcol]);
660 :
661 208364 : if (clauseset.indexclauses[indexcol] != NIL)
662 170775 : clauseset.nonempty = true;
663 : }
664 :
665 : /* We should have found something, else caller passed silly relids */
666 : Assert(clauseset.nonempty);
667 :
668 : /* Build index path(s) using the collected set of clauses */
669 135287 : get_index_paths(root, rel, index, &clauseset, bitindexpaths);
670 :
671 : /*
672 : * Remember we considered paths for this set of relids.
673 : */
674 135287 : *considered_relids = lappend(*considered_relids, relids);
675 : }
676 :
677 : /*
678 : * eclass_already_used
679 : * True if any join clause usable with oldrelids was generated from
680 : * the specified equivalence class.
681 : */
682 : static bool
683 8815 : eclass_already_used(EquivalenceClass *parent_ec, Relids oldrelids,
684 : List *indexjoinclauses)
685 : {
686 : ListCell *lc;
687 :
688 12203 : foreach(lc, indexjoinclauses)
689 : {
690 9240 : IndexClause *iclause = (IndexClause *) lfirst(lc);
691 9240 : RestrictInfo *rinfo = iclause->rinfo;
692 :
693 18480 : if (rinfo->parent_ec == parent_ec &&
694 9240 : bms_is_subset(rinfo->clause_relids, oldrelids))
695 5852 : return true;
696 : }
697 2963 : return false;
698 : }
699 :
700 :
701 : /*
702 : * get_index_paths
703 : * Given an index and a set of index clauses for it, construct IndexPaths.
704 : *
705 : * Plain indexpaths are sent directly to add_path, while potential
706 : * bitmap indexpaths are added to *bitindexpaths for later processing.
707 : *
708 : * This is a fairly simple frontend to build_index_paths(). Its reason for
709 : * existence is mainly to handle ScalarArrayOpExpr quals properly. If the
710 : * index AM supports them natively, we should just include them in simple
711 : * index paths. If not, we should exclude them while building simple index
712 : * paths, and then make a separate attempt to include them in bitmap paths.
713 : */
714 : static void
715 697500 : get_index_paths(PlannerInfo *root, RelOptInfo *rel,
716 : IndexOptInfo *index, IndexClauseSet *clauses,
717 : List **bitindexpaths)
718 : {
719 : List *indexpaths;
720 697500 : bool skip_nonnative_saop = false;
721 : ListCell *lc;
722 :
723 : /*
724 : * Build simple index paths using the clauses. Allow ScalarArrayOpExpr
725 : * clauses only if the index AM supports them natively.
726 : */
727 697500 : indexpaths = build_index_paths(root, rel,
728 : index, clauses,
729 697500 : index->predOK,
730 : ST_ANYSCAN,
731 : &skip_nonnative_saop);
732 :
733 : /*
734 : * Submit all the ones that can form plain IndexScan plans to add_path. (A
735 : * plain IndexPath can represent either a plain IndexScan or an
736 : * IndexOnlyScan, but for our purposes here that distinction does not
737 : * matter. However, some of the indexes might support only bitmap scans,
738 : * and those we mustn't submit to add_path here.)
739 : *
740 : * Also, pick out the ones that are usable as bitmap scans. For that, we
741 : * must discard indexes that don't support bitmap scans, and we also are
742 : * only interested in paths that have some selectivity; we should discard
743 : * anything that was generated solely for ordering purposes.
744 : */
745 1130650 : foreach(lc, indexpaths)
746 : {
747 433150 : IndexPath *ipath = (IndexPath *) lfirst(lc);
748 :
749 433150 : if (index->amhasgettuple)
750 422261 : add_path(rel, (Path *) ipath);
751 :
752 433150 : if (index->amhasgetbitmap &&
753 433150 : (ipath->path.pathkeys == NIL ||
754 289734 : ipath->indexselectivity < 1.0))
755 306579 : *bitindexpaths = lappend(*bitindexpaths, ipath);
756 : }
757 :
758 : /*
759 : * If there were ScalarArrayOpExpr clauses that the index can't handle
760 : * natively, generate bitmap scan paths relying on executor-managed
761 : * ScalarArrayOpExpr.
762 : */
763 697500 : if (skip_nonnative_saop)
764 : {
765 51 : indexpaths = build_index_paths(root, rel,
766 : index, clauses,
767 : false,
768 : ST_BITMAPSCAN,
769 : NULL);
770 51 : *bitindexpaths = list_concat(*bitindexpaths, indexpaths);
771 : }
772 697500 : }
773 :
774 : /*
775 : * build_index_paths
776 : * Given an index and a set of index clauses for it, construct zero
777 : * or more IndexPaths. It also constructs zero or more partial IndexPaths.
778 : *
779 : * We return a list of paths because (1) this routine checks some cases
780 : * that should cause us to not generate any IndexPath, and (2) in some
781 : * cases we want to consider both a forward and a backward scan, so as
782 : * to obtain both sort orders. Note that the paths are just returned
783 : * to the caller and not immediately fed to add_path().
784 : *
785 : * At top level, useful_predicate should be exactly the index's predOK flag
786 : * (ie, true if it has a predicate that was proven from the restriction
787 : * clauses). When working on an arm of an OR clause, useful_predicate
788 : * should be true if the predicate required the current OR list to be proven.
789 : * Note that this routine should never be called at all if the index has an
790 : * unprovable predicate.
791 : *
792 : * scantype indicates whether we want to create plain indexscans, bitmap
793 : * indexscans, or both. When it's ST_BITMAPSCAN, we will not consider
794 : * index ordering while deciding if a Path is worth generating.
795 : *
796 : * If skip_nonnative_saop is non-NULL, we ignore ScalarArrayOpExpr clauses
797 : * unless the index AM supports them directly, and we set *skip_nonnative_saop
798 : * to true if we found any such clauses (caller must initialize the variable
799 : * to false). If it's NULL, we do not ignore ScalarArrayOpExpr clauses.
800 : *
801 : * 'rel' is the index's heap relation
802 : * 'index' is the index for which we want to generate paths
803 : * 'clauses' is the collection of indexable clauses (IndexClause nodes)
804 : * 'useful_predicate' indicates whether the index has a useful predicate
805 : * 'scantype' indicates whether we need plain or bitmap scan support
806 : * 'skip_nonnative_saop' indicates whether to accept SAOP if index AM doesn't
807 : */
808 : static List *
809 701918 : build_index_paths(PlannerInfo *root, RelOptInfo *rel,
810 : IndexOptInfo *index, IndexClauseSet *clauses,
811 : bool useful_predicate,
812 : ScanTypeControl scantype,
813 : bool *skip_nonnative_saop)
814 : {
815 701918 : List *result = NIL;
816 : IndexPath *ipath;
817 : List *index_clauses;
818 : Relids outer_relids;
819 : double loop_count;
820 : List *orderbyclauses;
821 : List *orderbyclausecols;
822 : List *index_pathkeys;
823 : List *useful_pathkeys;
824 : bool pathkeys_possibly_useful;
825 : bool index_is_ordered;
826 : bool index_only_scan;
827 : int indexcol;
828 :
829 : Assert(skip_nonnative_saop != NULL || scantype == ST_BITMAPSCAN);
830 :
831 : /*
832 : * Check that index supports the desired scan type(s)
833 : */
834 701918 : switch (scantype)
835 : {
836 0 : case ST_INDEXSCAN:
837 0 : if (!index->amhasgettuple)
838 0 : return NIL;
839 0 : break;
840 4418 : case ST_BITMAPSCAN:
841 4418 : if (!index->amhasgetbitmap)
842 0 : return NIL;
843 4418 : break;
844 697500 : case ST_ANYSCAN:
845 : /* either or both are OK */
846 697500 : break;
847 : }
848 :
849 : /*
850 : * 1. Combine the per-column IndexClause lists into an overall list.
851 : *
852 : * In the resulting list, clauses are ordered by index key, so that the
853 : * column numbers form a nondecreasing sequence. (This order is depended
854 : * on by btree and possibly other places.) The list can be empty, if the
855 : * index AM allows that.
856 : *
857 : * We also build a Relids set showing which outer rels are required by the
858 : * selected clauses. Any lateral_relids are included in that, but not
859 : * otherwise accounted for.
860 : */
861 701918 : index_clauses = NIL;
862 701918 : outer_relids = bms_copy(rel->lateral_relids);
863 1984683 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
864 : {
865 : ListCell *lc;
866 :
867 1649211 : foreach(lc, clauses->indexclauses[indexcol])
868 : {
869 366163 : IndexClause *iclause = (IndexClause *) lfirst(lc);
870 366163 : RestrictInfo *rinfo = iclause->rinfo;
871 :
872 366163 : if (skip_nonnative_saop && !index->amsearcharray &&
873 18894 : IsA(rinfo->clause, ScalarArrayOpExpr))
874 : {
875 : /*
876 : * Caller asked us to generate IndexPaths that omit any
877 : * ScalarArrayOpExpr clauses when the underlying index AM
878 : * lacks native support.
879 : *
880 : * We must omit this clause (and tell caller about it).
881 : */
882 51 : *skip_nonnative_saop = true;
883 51 : continue;
884 : }
885 :
886 : /* OK to include this clause */
887 366112 : index_clauses = lappend(index_clauses, iclause);
888 366112 : outer_relids = bms_add_members(outer_relids,
889 366112 : rinfo->clause_relids);
890 : }
891 :
892 : /*
893 : * If no clauses match the first index column, check for amoptionalkey
894 : * restriction. We can't generate a scan over an index with
895 : * amoptionalkey = false unless there's at least one index clause.
896 : * (When working on columns after the first, this test cannot fail. It
897 : * is always okay for columns after the first to not have any
898 : * clauses.)
899 : */
900 1283048 : if (index_clauses == NIL && !index->amoptionalkey)
901 283 : return NIL;
902 : }
903 :
904 : /* We do not want the index's rel itself listed in outer_relids */
905 701635 : outer_relids = bms_del_member(outer_relids, rel->relid);
906 :
907 : /* Compute loop_count for cost estimation purposes */
908 701635 : loop_count = get_loop_count(root, rel->relid, outer_relids);
909 :
910 : /*
911 : * 2. Compute pathkeys describing index's ordering, if any, then see how
912 : * many of them are actually useful for this query. This is not relevant
913 : * if we are only trying to build bitmap indexscans.
914 : */
915 1398852 : pathkeys_possibly_useful = (scantype != ST_BITMAPSCAN &&
916 697217 : has_useful_pathkeys(root, rel));
917 701635 : index_is_ordered = (index->sortopfamily != NULL);
918 701635 : if (index_is_ordered && pathkeys_possibly_useful)
919 : {
920 546891 : index_pathkeys = build_index_pathkeys(root, index,
921 : ForwardScanDirection);
922 546891 : useful_pathkeys = truncate_useless_pathkeys(root, rel,
923 : index_pathkeys);
924 546891 : orderbyclauses = NIL;
925 546891 : orderbyclausecols = NIL;
926 : }
927 154744 : else if (index->amcanorderbyop && pathkeys_possibly_useful)
928 : {
929 : /*
930 : * See if we can generate ordering operators for query_pathkeys or at
931 : * least some prefix thereof. Matching to just a prefix of the
932 : * query_pathkeys will allow an incremental sort to be considered on
933 : * the index's partially sorted results.
934 : */
935 1340 : match_pathkeys_to_index(index, root->query_pathkeys,
936 : &orderbyclauses,
937 : &orderbyclausecols);
938 2680 : if (list_length(root->query_pathkeys) == list_length(orderbyclauses))
939 379 : useful_pathkeys = root->query_pathkeys;
940 : else
941 961 : useful_pathkeys = list_copy_head(root->query_pathkeys,
942 : list_length(orderbyclauses));
943 : }
944 : else
945 : {
946 153404 : useful_pathkeys = NIL;
947 153404 : orderbyclauses = NIL;
948 153404 : orderbyclausecols = NIL;
949 : }
950 :
951 : /*
952 : * 3. Check if an index-only scan is possible. If we're not building
953 : * plain indexscans, this isn't relevant since bitmap scans don't support
954 : * index data retrieval anyway.
955 : */
956 1398852 : index_only_scan = (scantype != ST_BITMAPSCAN &&
957 697217 : check_index_only(rel, index));
958 :
959 : /*
960 : * 4. Generate an indexscan path if there are relevant restriction clauses
961 : * in the current clauses, OR the index ordering is potentially useful for
962 : * later merging or final output ordering, OR the index has a useful
963 : * predicate, OR an index-only scan is possible.
964 : */
965 701635 : if (index_clauses != NIL || useful_pathkeys != NIL || useful_predicate ||
966 : index_only_scan)
967 : {
968 437069 : ipath = create_index_path(root, index,
969 : index_clauses,
970 : orderbyclauses,
971 : orderbyclausecols,
972 : useful_pathkeys,
973 : ForwardScanDirection,
974 : index_only_scan,
975 : outer_relids,
976 : loop_count,
977 : false);
978 437069 : result = lappend(result, ipath);
979 :
980 : /*
981 : * If appropriate, consider parallel index scan. We don't allow
982 : * parallel index scan for bitmap index scans.
983 : */
984 437069 : if (index->amcanparallel &&
985 419623 : rel->consider_parallel && outer_relids == NULL &&
986 : scantype != ST_BITMAPSCAN)
987 : {
988 227033 : ipath = create_index_path(root, index,
989 : index_clauses,
990 : orderbyclauses,
991 : orderbyclausecols,
992 : useful_pathkeys,
993 : ForwardScanDirection,
994 : index_only_scan,
995 : outer_relids,
996 : loop_count,
997 : true);
998 :
999 : /*
1000 : * if, after costing the path, we find that it's not worth using
1001 : * parallel workers, just free it.
1002 : */
1003 227033 : if (ipath->path.parallel_workers > 0)
1004 7520 : add_partial_path(rel, (Path *) ipath);
1005 : else
1006 219513 : pfree(ipath);
1007 : }
1008 : }
1009 :
1010 : /*
1011 : * 5. If the index is ordered, a backwards scan might be interesting.
1012 : */
1013 701635 : if (index_is_ordered && pathkeys_possibly_useful)
1014 : {
1015 546891 : index_pathkeys = build_index_pathkeys(root, index,
1016 : BackwardScanDirection);
1017 546891 : useful_pathkeys = truncate_useless_pathkeys(root, rel,
1018 : index_pathkeys);
1019 546891 : if (useful_pathkeys != NIL)
1020 : {
1021 499 : ipath = create_index_path(root, index,
1022 : index_clauses,
1023 : NIL,
1024 : NIL,
1025 : useful_pathkeys,
1026 : BackwardScanDirection,
1027 : index_only_scan,
1028 : outer_relids,
1029 : loop_count,
1030 : false);
1031 499 : result = lappend(result, ipath);
1032 :
1033 : /* If appropriate, consider parallel index scan */
1034 499 : if (index->amcanparallel &&
1035 499 : rel->consider_parallel && outer_relids == NULL &&
1036 : scantype != ST_BITMAPSCAN)
1037 : {
1038 416 : ipath = create_index_path(root, index,
1039 : index_clauses,
1040 : NIL,
1041 : NIL,
1042 : useful_pathkeys,
1043 : BackwardScanDirection,
1044 : index_only_scan,
1045 : outer_relids,
1046 : loop_count,
1047 : true);
1048 :
1049 : /*
1050 : * if, after costing the path, we find that it's not worth
1051 : * using parallel workers, just free it.
1052 : */
1053 416 : if (ipath->path.parallel_workers > 0)
1054 140 : add_partial_path(rel, (Path *) ipath);
1055 : else
1056 276 : pfree(ipath);
1057 : }
1058 : }
1059 : }
1060 :
1061 701635 : return result;
1062 : }
1063 :
1064 : /*
1065 : * build_paths_for_OR
1066 : * Given a list of restriction clauses from one arm of an OR clause,
1067 : * construct all matching IndexPaths for the relation.
1068 : *
1069 : * Here we must scan all indexes of the relation, since a bitmap OR tree
1070 : * can use multiple indexes.
1071 : *
1072 : * The caller actually supplies two lists of restriction clauses: some
1073 : * "current" ones and some "other" ones. Both lists can be used freely
1074 : * to match keys of the index, but an index must use at least one of the
1075 : * "current" clauses to be considered usable. The motivation for this is
1076 : * examples like
1077 : * WHERE (x = 42) AND (... OR (y = 52 AND z = 77) OR ....)
1078 : * While we are considering the y/z subclause of the OR, we can use "x = 42"
1079 : * as one of the available index conditions; but we shouldn't match the
1080 : * subclause to any index on x alone, because such a Path would already have
1081 : * been generated at the upper level. So we could use an index on x,y,z
1082 : * or an index on x,y for the OR subclause, but not an index on just x.
1083 : * When dealing with a partial index, a match of the index predicate to
1084 : * one of the "current" clauses also makes the index usable.
1085 : *
1086 : * 'rel' is the relation for which we want to generate index paths
1087 : * 'clauses' is the current list of clauses (RestrictInfo nodes)
1088 : * 'other_clauses' is the list of additional upper-level clauses
1089 : */
1090 : static List *
1091 10512 : build_paths_for_OR(PlannerInfo *root, RelOptInfo *rel,
1092 : List *clauses, List *other_clauses)
1093 : {
1094 10512 : List *result = NIL;
1095 10512 : List *all_clauses = NIL; /* not computed till needed */
1096 : ListCell *lc;
1097 :
1098 37830 : foreach(lc, rel->indexlist)
1099 : {
1100 27318 : IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
1101 : IndexClauseSet clauseset;
1102 : List *indexpaths;
1103 : bool useful_predicate;
1104 :
1105 : /* Ignore index if it doesn't support bitmap scans */
1106 27318 : if (!index->amhasgetbitmap)
1107 22951 : continue;
1108 :
1109 : /*
1110 : * Ignore partial indexes that do not match the query. If a partial
1111 : * index is marked predOK then we know it's OK. Otherwise, we have to
1112 : * test whether the added clauses are sufficient to imply the
1113 : * predicate. If so, we can use the index in the current context.
1114 : *
1115 : * We set useful_predicate to true iff the predicate was proven using
1116 : * the current set of clauses. This is needed to prevent matching a
1117 : * predOK index to an arm of an OR, which would be a legal but
1118 : * pointlessly inefficient plan. (A better plan will be generated by
1119 : * just scanning the predOK index alone, no OR.)
1120 : */
1121 27318 : useful_predicate = false;
1122 27318 : if (index->indpred != NIL)
1123 : {
1124 140 : if (index->predOK)
1125 : {
1126 : /* Usable, but don't set useful_predicate */
1127 : }
1128 : else
1129 : {
1130 : /* Form all_clauses if not done already */
1131 120 : if (all_clauses == NIL)
1132 50 : all_clauses = list_concat_copy(clauses, other_clauses);
1133 :
1134 120 : if (!predicate_implied_by(index->indpred, all_clauses, false))
1135 80 : continue; /* can't use it at all */
1136 :
1137 40 : if (!predicate_implied_by(index->indpred, other_clauses, false))
1138 40 : useful_predicate = true;
1139 : }
1140 : }
1141 :
1142 : /*
1143 : * Identify the restriction clauses that can match the index.
1144 : */
1145 926092 : MemSet(&clauseset, 0, sizeof(clauseset));
1146 27238 : match_clauses_to_index(root, clauses, index, &clauseset);
1147 :
1148 : /*
1149 : * If no matches so far, and the index predicate isn't useful, we
1150 : * don't want it.
1151 : */
1152 27238 : if (!clauseset.nonempty && !useful_predicate)
1153 22871 : continue;
1154 :
1155 : /*
1156 : * Add "other" restriction clauses to the clauseset.
1157 : */
1158 4367 : match_clauses_to_index(root, other_clauses, index, &clauseset);
1159 :
1160 : /*
1161 : * Construct paths if possible.
1162 : */
1163 4367 : indexpaths = build_index_paths(root, rel,
1164 : index, &clauseset,
1165 : useful_predicate,
1166 : ST_BITMAPSCAN,
1167 : NULL);
1168 4367 : result = list_concat(result, indexpaths);
1169 : }
1170 :
1171 10512 : return result;
1172 : }
1173 :
1174 : /*
1175 : * Utility structure used to group similar OR-clause arguments in
1176 : * group_similar_or_args(). It represents information about the OR-clause
1177 : * argument and its matching index key.
1178 : */
1179 : typedef struct
1180 : {
1181 : int indexnum; /* index of the matching index, or -1 if no
1182 : * matching index */
1183 : int colnum; /* index of the matching column, or -1 if no
1184 : * matching index */
1185 : Oid opno; /* OID of the OpClause operator, or InvalidOid
1186 : * if not an OpExpr */
1187 : Oid inputcollid; /* OID of the OpClause input collation */
1188 : int argindex; /* index of the clause in the list of
1189 : * arguments */
1190 : int groupindex; /* value of argindex for the first clause in
1191 : * the group of similar clauses */
1192 : } OrArgIndexMatch;
1193 :
1194 : /*
1195 : * Comparison function for OrArgIndexMatch which provides sort order placing
1196 : * similar OR-clause arguments together.
1197 : */
1198 : static int
1199 6874 : or_arg_index_match_cmp(const void *a, const void *b)
1200 : {
1201 6874 : const OrArgIndexMatch *match_a = (const OrArgIndexMatch *) a;
1202 6874 : const OrArgIndexMatch *match_b = (const OrArgIndexMatch *) b;
1203 :
1204 6874 : if (match_a->indexnum < match_b->indexnum)
1205 1072 : return -1;
1206 5802 : else if (match_a->indexnum > match_b->indexnum)
1207 2376 : return 1;
1208 :
1209 3426 : if (match_a->colnum < match_b->colnum)
1210 621 : return -1;
1211 2805 : else if (match_a->colnum > match_b->colnum)
1212 20 : return 1;
1213 :
1214 2785 : if (match_a->opno < match_b->opno)
1215 15 : return -1;
1216 2770 : else if (match_a->opno > match_b->opno)
1217 35 : return 1;
1218 :
1219 2735 : if (match_a->inputcollid < match_b->inputcollid)
1220 0 : return -1;
1221 2735 : else if (match_a->inputcollid > match_b->inputcollid)
1222 0 : return 1;
1223 :
1224 2735 : if (match_a->argindex < match_b->argindex)
1225 2605 : return -1;
1226 130 : else if (match_a->argindex > match_b->argindex)
1227 130 : return 1;
1228 :
1229 0 : return 0;
1230 : }
1231 :
1232 : /*
1233 : * Another comparison function for OrArgIndexMatch. It sorts groups together
1234 : * using groupindex. The group items are then sorted by argindex.
1235 : */
1236 : static int
1237 6984 : or_arg_index_match_cmp_group(const void *a, const void *b)
1238 : {
1239 6984 : const OrArgIndexMatch *match_a = (const OrArgIndexMatch *) a;
1240 6984 : const OrArgIndexMatch *match_b = (const OrArgIndexMatch *) b;
1241 :
1242 6984 : if (match_a->groupindex < match_b->groupindex)
1243 3034 : return -1;
1244 3950 : else if (match_a->groupindex > match_b->groupindex)
1245 2586 : return 1;
1246 :
1247 1364 : if (match_a->argindex < match_b->argindex)
1248 1364 : return -1;
1249 0 : else if (match_a->argindex > match_b->argindex)
1250 0 : return 1;
1251 :
1252 0 : return 0;
1253 : }
1254 :
1255 : /*
1256 : * group_similar_or_args
1257 : * Transform incoming OR-restrictinfo into a list of sub-restrictinfos,
1258 : * each of them containing a subset of similar OR-clause arguments from
1259 : * the source rinfo.
1260 : *
1261 : * Similar OR-clause arguments are of the form "indexkey op constant" having
1262 : * the same indexkey, operator, and collation. Constant may comprise either
1263 : * Const or Param. It may be employed later, during the
1264 : * match_clause_to_indexcol() to transform the whole OR-sub-rinfo to an SAOP
1265 : * clause.
1266 : *
1267 : * Returns the processed list of OR-clause arguments.
1268 : */
1269 : static List *
1270 8172 : group_similar_or_args(PlannerInfo *root, RelOptInfo *rel, RestrictInfo *rinfo)
1271 : {
1272 : int n;
1273 : int i;
1274 : int group_start;
1275 : OrArgIndexMatch *matches;
1276 8172 : bool matched = false;
1277 : ListCell *lc;
1278 : ListCell *lc2;
1279 : List *orargs;
1280 8172 : List *result = NIL;
1281 8172 : Index relid = rel->relid;
1282 :
1283 : Assert(IsA(rinfo->orclause, BoolExpr));
1284 8172 : orargs = ((BoolExpr *) rinfo->orclause)->args;
1285 8172 : n = list_length(orargs);
1286 :
1287 : /*
1288 : * To avoid N^2 behavior, take utility pass along the list of OR-clause
1289 : * arguments. For each argument, fill the OrArgIndexMatch structure,
1290 : * which will be used to sort these arguments at the next step.
1291 : */
1292 8172 : i = -1;
1293 8172 : matches = palloc_array(OrArgIndexMatch, n);
1294 27462 : foreach(lc, orargs)
1295 : {
1296 19290 : Node *arg = lfirst(lc);
1297 : RestrictInfo *argrinfo;
1298 : OpExpr *clause;
1299 : Oid opno;
1300 : Node *leftop,
1301 : *rightop;
1302 : Node *nonConstExpr;
1303 : int indexnum;
1304 : int colnum;
1305 :
1306 19290 : i++;
1307 19290 : matches[i].argindex = i;
1308 19290 : matches[i].groupindex = i;
1309 19290 : matches[i].indexnum = -1;
1310 19290 : matches[i].colnum = -1;
1311 19290 : matches[i].opno = InvalidOid;
1312 19290 : matches[i].inputcollid = InvalidOid;
1313 :
1314 19290 : if (!IsA(arg, RestrictInfo))
1315 1746 : continue;
1316 :
1317 17544 : argrinfo = castNode(RestrictInfo, arg);
1318 :
1319 : /* Only operator clauses can match */
1320 17544 : if (!IsA(argrinfo->clause, OpExpr))
1321 6700 : continue;
1322 :
1323 10844 : clause = (OpExpr *) argrinfo->clause;
1324 10844 : opno = clause->opno;
1325 :
1326 : /* Only binary operators can match */
1327 10844 : if (list_length(clause->args) != 2)
1328 0 : continue;
1329 :
1330 : /*
1331 : * Ignore any RelabelType node above the operands. This is needed to
1332 : * be able to apply indexscanning in binary-compatible-operator cases.
1333 : * Note: we can assume there is at most one RelabelType node;
1334 : * eval_const_expressions() will have simplified if more than one.
1335 : */
1336 10844 : leftop = get_leftop(clause);
1337 10844 : if (IsA(leftop, RelabelType))
1338 195 : leftop = (Node *) ((RelabelType *) leftop)->arg;
1339 :
1340 10844 : rightop = get_rightop(clause);
1341 10844 : if (IsA(rightop, RelabelType))
1342 566 : rightop = (Node *) ((RelabelType *) rightop)->arg;
1343 :
1344 : /*
1345 : * Check for clauses of the form: (indexkey operator constant) or
1346 : * (constant operator indexkey). But we don't know a particular index
1347 : * yet. Therefore, we try to distinguish the potential index key and
1348 : * constant first, then search for a matching index key among all
1349 : * indexes.
1350 : */
1351 10844 : if (bms_is_member(relid, argrinfo->right_relids) &&
1352 1515 : !bms_is_member(relid, argrinfo->left_relids) &&
1353 1455 : !contain_volatile_functions(leftop))
1354 : {
1355 1455 : opno = get_commutator(opno);
1356 :
1357 1455 : if (!OidIsValid(opno))
1358 : {
1359 : /* commutator doesn't exist, we can't reverse the order */
1360 0 : continue;
1361 : }
1362 1455 : nonConstExpr = rightop;
1363 : }
1364 9389 : else if (bms_is_member(relid, argrinfo->left_relids) &&
1365 7729 : !bms_is_member(relid, argrinfo->right_relids) &&
1366 7669 : !contain_volatile_functions(rightop))
1367 : {
1368 7669 : nonConstExpr = leftop;
1369 : }
1370 : else
1371 : {
1372 1720 : continue;
1373 : }
1374 :
1375 : /*
1376 : * Match non-constant part to the index key. It's possible that a
1377 : * single non-constant part matches multiple index keys. It's OK, we
1378 : * just stop with first matching index key. Given that this choice is
1379 : * determined the same for every clause, we will group similar clauses
1380 : * together anyway.
1381 : */
1382 9124 : indexnum = 0;
1383 19621 : foreach(lc2, rel->indexlist)
1384 : {
1385 16641 : IndexOptInfo *index = (IndexOptInfo *) lfirst(lc2);
1386 :
1387 : /*
1388 : * Ignore index if it doesn't support bitmap scans or SAOP
1389 : * clauses.
1390 : */
1391 16641 : if (!index->amhasgetbitmap || !index->amsearcharray)
1392 35 : continue;
1393 :
1394 34751 : for (colnum = 0; colnum < index->nkeycolumns; colnum++)
1395 : {
1396 24289 : if (match_index_to_operand(nonConstExpr, colnum, index))
1397 : {
1398 6144 : matches[i].indexnum = indexnum;
1399 6144 : matches[i].colnum = colnum;
1400 6144 : matches[i].opno = opno;
1401 6144 : matches[i].inputcollid = clause->inputcollid;
1402 6144 : matched = true;
1403 6144 : break;
1404 : }
1405 : }
1406 :
1407 : /*
1408 : * Stop looping through the indexes, if we managed to match
1409 : * nonConstExpr to any index column.
1410 : */
1411 16606 : if (matches[i].indexnum >= 0)
1412 6144 : break;
1413 10462 : indexnum++;
1414 : }
1415 : }
1416 :
1417 : /*
1418 : * Fast-path check: if no clause is matching to the index column, we can
1419 : * just give up at this stage and return the clause list as-is.
1420 : */
1421 8172 : if (!matched)
1422 : {
1423 4225 : pfree(matches);
1424 4225 : return orargs;
1425 : }
1426 :
1427 : /*
1428 : * Sort clauses to make similar clauses go together. But at the same
1429 : * time, we would like to change the order of clauses as little as
1430 : * possible. To do so, we reorder each group of similar clauses so that
1431 : * the first item of the group stays in place, and all the other items are
1432 : * moved after it. So, if there are no similar clauses, the order of
1433 : * clauses stays the same. When there are some groups, required
1434 : * reordering happens while the rest of the clauses remain in their
1435 : * places. That is achieved by assigning a 'groupindex' to each clause:
1436 : * the number of the first item in the group in the original clause list.
1437 : */
1438 3947 : qsort(matches, n, sizeof(OrArgIndexMatch), or_arg_index_match_cmp);
1439 :
1440 : /* Assign groupindex to the sorted clauses */
1441 9355 : for (i = 1; i < n; i++)
1442 : {
1443 : /*
1444 : * When two clauses are similar and should belong to the same group,
1445 : * copy the 'groupindex' from the previous clause. Given we are
1446 : * considering clauses in direct order, all the clauses would have a
1447 : * 'groupindex' equal to the 'groupindex' of the first clause in the
1448 : * group.
1449 : */
1450 5408 : if (matches[i].indexnum == matches[i - 1].indexnum &&
1451 3166 : matches[i].colnum == matches[i - 1].colnum &&
1452 2535 : matches[i].opno == matches[i - 1].opno &&
1453 2495 : matches[i].inputcollid == matches[i - 1].inputcollid &&
1454 2495 : matches[i].indexnum != -1)
1455 1364 : matches[i].groupindex = matches[i - 1].groupindex;
1456 : }
1457 :
1458 : /* Re-sort clauses first by groupindex then by argindex */
1459 3947 : qsort(matches, n, sizeof(OrArgIndexMatch), or_arg_index_match_cmp_group);
1460 :
1461 : /*
1462 : * Group similar clauses into single sub-restrictinfo. Side effect: the
1463 : * resulting list of restrictions will be sorted by indexnum and colnum.
1464 : */
1465 3947 : group_start = 0;
1466 13302 : for (i = 1; i <= n; i++)
1467 : {
1468 : /* Check if it's a group boundary */
1469 9355 : if (group_start >= 0 &&
1470 5408 : (i == n ||
1471 5408 : matches[i].indexnum != matches[group_start].indexnum ||
1472 3031 : matches[i].colnum != matches[group_start].colnum ||
1473 2415 : matches[i].opno != matches[group_start].opno ||
1474 2380 : matches[i].inputcollid != matches[group_start].inputcollid ||
1475 2380 : matches[i].indexnum == -1))
1476 : {
1477 : /*
1478 : * One clause in group: add it "as is" to the upper-level OR.
1479 : */
1480 7991 : if (i - group_start == 1)
1481 : {
1482 6737 : result = lappend(result,
1483 : list_nth(orargs,
1484 6737 : matches[group_start].argindex));
1485 : }
1486 : else
1487 : {
1488 : /*
1489 : * Two or more clauses in a group: create a nested OR.
1490 : */
1491 1254 : List *args = NIL;
1492 1254 : List *rargs = NIL;
1493 : RestrictInfo *subrinfo;
1494 : int j;
1495 :
1496 : Assert(i - group_start >= 2);
1497 :
1498 : /* Construct the list of nested OR arguments */
1499 3872 : for (j = group_start; j < i; j++)
1500 : {
1501 2618 : Node *arg = list_nth(orargs, matches[j].argindex);
1502 :
1503 2618 : rargs = lappend(rargs, arg);
1504 2618 : if (IsA(arg, RestrictInfo))
1505 2618 : args = lappend(args, ((RestrictInfo *) arg)->clause);
1506 : else
1507 0 : args = lappend(args, arg);
1508 : }
1509 :
1510 : /* Construct the nested OR and wrap it with RestrictInfo */
1511 1254 : subrinfo = make_plain_restrictinfo(root,
1512 : make_orclause(args),
1513 : make_orclause(rargs),
1514 1254 : rinfo->is_pushed_down,
1515 1254 : rinfo->has_clone,
1516 1254 : rinfo->is_clone,
1517 1254 : rinfo->pseudoconstant,
1518 : rinfo->security_level,
1519 : rinfo->required_relids,
1520 : rinfo->incompatible_relids,
1521 : rinfo->outer_relids);
1522 1254 : result = lappend(result, subrinfo);
1523 : }
1524 :
1525 7991 : group_start = i;
1526 : }
1527 : }
1528 3947 : pfree(matches);
1529 3947 : return result;
1530 : }
1531 :
1532 : /*
1533 : * make_bitmap_paths_for_or_group
1534 : * Generate bitmap paths for a group of similar OR-clause arguments
1535 : * produced by group_similar_or_args().
1536 : *
1537 : * This function considers two cases: (1) matching a group of clauses to
1538 : * the index as a whole, and (2) matching the individual clauses one-by-one.
1539 : * (1) typically comprises an optimal solution. If not, (2) typically
1540 : * comprises fair alternative.
1541 : *
1542 : * Ideally, we could consider all arbitrary splits of arguments into
1543 : * subgroups, but that could lead to unacceptable computational complexity.
1544 : * This is why we only consider two cases of above.
1545 : */
1546 : static List *
1547 1249 : make_bitmap_paths_for_or_group(PlannerInfo *root, RelOptInfo *rel,
1548 : RestrictInfo *ri, List *other_clauses)
1549 : {
1550 1249 : List *jointlist = NIL;
1551 1249 : List *splitlist = NIL;
1552 : ListCell *lc;
1553 : List *orargs;
1554 1249 : List *args = ((BoolExpr *) ri->orclause)->args;
1555 1249 : Cost jointcost = 0.0,
1556 1249 : splitcost = 0.0;
1557 : Path *bitmapqual;
1558 : List *indlist;
1559 :
1560 : /*
1561 : * First, try to match the whole group to the one index.
1562 : */
1563 1249 : orargs = list_make1(ri);
1564 1249 : indlist = build_paths_for_OR(root, rel,
1565 : orargs,
1566 : other_clauses);
1567 1249 : if (indlist != NIL)
1568 : {
1569 1244 : bitmapqual = choose_bitmap_and(root, rel, indlist);
1570 1244 : jointcost = bitmapqual->total_cost;
1571 1244 : jointlist = list_make1(bitmapqual);
1572 : }
1573 :
1574 : /*
1575 : * If we manage to find a bitmap scan, which uses the group of OR-clause
1576 : * arguments as a whole, we can skip matching OR-clause arguments
1577 : * one-by-one as long as there are no other clauses, which can bring more
1578 : * efficiency to one-by-one case.
1579 : */
1580 1249 : if (jointlist != NIL && other_clauses == NIL)
1581 568 : return jointlist;
1582 :
1583 : /*
1584 : * Also try to match all containing clauses one-by-one.
1585 : */
1586 2128 : foreach(lc, args)
1587 : {
1588 1452 : orargs = list_make1(lfirst(lc));
1589 :
1590 1452 : indlist = build_paths_for_OR(root, rel,
1591 : orargs,
1592 : other_clauses);
1593 :
1594 1452 : if (indlist == NIL)
1595 : {
1596 5 : splitlist = NIL;
1597 5 : break;
1598 : }
1599 :
1600 1447 : bitmapqual = choose_bitmap_and(root, rel, indlist);
1601 1447 : splitcost += bitmapqual->total_cost;
1602 1447 : splitlist = lappend(splitlist, bitmapqual);
1603 : }
1604 :
1605 : /*
1606 : * Pick the best option.
1607 : */
1608 681 : if (splitlist == NIL)
1609 5 : return jointlist;
1610 676 : else if (jointlist == NIL)
1611 0 : return splitlist;
1612 : else
1613 676 : return (jointcost < splitcost) ? jointlist : splitlist;
1614 : }
1615 :
1616 :
1617 : /*
1618 : * generate_bitmap_or_paths
1619 : * Look through the list of clauses to find OR clauses, and generate
1620 : * a BitmapOrPath for each one we can handle that way. Return a list
1621 : * of the generated BitmapOrPaths.
1622 : *
1623 : * other_clauses is a list of additional clauses that can be assumed true
1624 : * for the purpose of generating indexquals, but are not to be searched for
1625 : * ORs. (See build_paths_for_OR() for motivation.)
1626 : */
1627 : static List *
1628 521581 : generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel,
1629 : List *clauses, List *other_clauses)
1630 : {
1631 521581 : List *result = NIL;
1632 : List *all_clauses;
1633 : ListCell *lc;
1634 :
1635 : /*
1636 : * We can use both the current and other clauses as context for
1637 : * build_paths_for_OR; no need to remove ORs from the lists.
1638 : */
1639 521581 : all_clauses = list_concat_copy(clauses, other_clauses);
1640 :
1641 802280 : foreach(lc, clauses)
1642 : {
1643 280699 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
1644 : List *pathlist;
1645 : Path *bitmapqual;
1646 : ListCell *j;
1647 : List *groupedArgs;
1648 280699 : List *inner_other_clauses = NIL;
1649 :
1650 : /* Ignore RestrictInfos that aren't ORs */
1651 280699 : if (!restriction_is_or_clause(rinfo))
1652 272527 : continue;
1653 :
1654 : /*
1655 : * We must be able to match at least one index to each of the arms of
1656 : * the OR, else we can't use it.
1657 : */
1658 8172 : pathlist = NIL;
1659 :
1660 : /*
1661 : * Group the similar OR-clause arguments into dedicated RestrictInfos,
1662 : * because each of those RestrictInfos has a chance to match the index
1663 : * as a whole.
1664 : */
1665 8172 : groupedArgs = group_similar_or_args(root, rel, rinfo);
1666 :
1667 8172 : if (groupedArgs != ((BoolExpr *) rinfo->orclause)->args)
1668 : {
1669 : /*
1670 : * Some parts of the rinfo were probably grouped. In this case,
1671 : * we have a set of sub-rinfos that together are an exact
1672 : * duplicate of rinfo. Thus, we need to remove the rinfo from
1673 : * other clauses. match_clauses_to_index detects duplicated
1674 : * iclauses by comparing pointers to original rinfos that would be
1675 : * different. So, we must delete rinfo to avoid de-facto
1676 : * duplicated clauses in the index clauses list.
1677 : */
1678 3947 : inner_other_clauses = list_delete(list_copy(all_clauses), rinfo);
1679 : }
1680 :
1681 10812 : foreach(j, groupedArgs)
1682 : {
1683 9060 : Node *orarg = (Node *) lfirst(j);
1684 : List *indlist;
1685 :
1686 : /* OR arguments should be ANDs or sub-RestrictInfos */
1687 9060 : if (is_andclause(orarg))
1688 : {
1689 985 : List *andargs = ((BoolExpr *) orarg)->args;
1690 :
1691 985 : indlist = build_paths_for_OR(root, rel,
1692 : andargs,
1693 : all_clauses);
1694 :
1695 : /* Recurse in case there are sub-ORs */
1696 985 : indlist = list_concat(indlist,
1697 985 : generate_bitmap_or_paths(root, rel,
1698 : andargs,
1699 : all_clauses));
1700 : }
1701 8075 : else if (restriction_is_or_clause(castNode(RestrictInfo, orarg)))
1702 : {
1703 1249 : RestrictInfo *ri = castNode(RestrictInfo, orarg);
1704 :
1705 : /*
1706 : * Generate bitmap paths for the group of similar OR-clause
1707 : * arguments.
1708 : */
1709 1249 : indlist = make_bitmap_paths_for_or_group(root,
1710 : rel, ri,
1711 : inner_other_clauses);
1712 :
1713 1249 : if (indlist == NIL)
1714 : {
1715 5 : pathlist = NIL;
1716 5 : break;
1717 : }
1718 : else
1719 : {
1720 1244 : pathlist = list_concat(pathlist, indlist);
1721 1244 : continue;
1722 : }
1723 : }
1724 : else
1725 : {
1726 6826 : RestrictInfo *ri = castNode(RestrictInfo, orarg);
1727 : List *orargs;
1728 :
1729 6826 : orargs = list_make1(ri);
1730 :
1731 6826 : indlist = build_paths_for_OR(root, rel,
1732 : orargs,
1733 : all_clauses);
1734 : }
1735 :
1736 : /*
1737 : * If nothing matched this arm, we can't do anything with this OR
1738 : * clause.
1739 : */
1740 7811 : if (indlist == NIL)
1741 : {
1742 6415 : pathlist = NIL;
1743 6415 : break;
1744 : }
1745 :
1746 : /*
1747 : * OK, pick the most promising AND combination, and add it to
1748 : * pathlist.
1749 : */
1750 1396 : bitmapqual = choose_bitmap_and(root, rel, indlist);
1751 1396 : pathlist = lappend(pathlist, bitmapqual);
1752 : }
1753 :
1754 8172 : if (inner_other_clauses != NIL)
1755 2054 : list_free(inner_other_clauses);
1756 :
1757 : /*
1758 : * If we have a match for every arm, then turn them into a
1759 : * BitmapOrPath, and add to result list.
1760 : */
1761 8172 : if (pathlist != NIL)
1762 : {
1763 1752 : bitmapqual = (Path *) create_bitmap_or_path(root, rel, pathlist);
1764 1752 : result = lappend(result, bitmapqual);
1765 : }
1766 : }
1767 :
1768 521581 : return result;
1769 : }
1770 :
1771 :
1772 : /*
1773 : * choose_bitmap_and
1774 : * Given a nonempty list of bitmap paths, AND them into one path.
1775 : *
1776 : * This is a nontrivial decision since we can legally use any subset of the
1777 : * given path set. We want to choose a good tradeoff between selectivity
1778 : * and cost of computing the bitmap.
1779 : *
1780 : * The result is either a single one of the inputs, or a BitmapAndPath
1781 : * combining multiple inputs.
1782 : */
1783 : static Path *
1784 281135 : choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel, List *paths)
1785 : {
1786 281135 : int npaths = list_length(paths);
1787 : PathClauseUsage **pathinfoarray;
1788 : PathClauseUsage *pathinfo;
1789 : List *clauselist;
1790 281135 : List *bestpaths = NIL;
1791 281135 : Cost bestcost = 0;
1792 : int i,
1793 : j;
1794 : ListCell *l;
1795 :
1796 : Assert(npaths > 0); /* else caller error */
1797 281135 : if (npaths == 1)
1798 214064 : return (Path *) linitial(paths); /* easy case */
1799 :
1800 : /*
1801 : * In theory we should consider every nonempty subset of the given paths.
1802 : * In practice that seems like overkill, given the crude nature of the
1803 : * estimates, not to mention the possible effects of higher-level AND and
1804 : * OR clauses. Moreover, it's completely impractical if there are a large
1805 : * number of paths, since the work would grow as O(2^N).
1806 : *
1807 : * As a heuristic, we first check for paths using exactly the same sets of
1808 : * WHERE clauses + index predicate conditions, and reject all but the
1809 : * cheapest-to-scan in any such group. This primarily gets rid of indexes
1810 : * that include the interesting columns but also irrelevant columns. (In
1811 : * situations where the DBA has gone overboard on creating variant
1812 : * indexes, this can make for a very large reduction in the number of
1813 : * paths considered further.)
1814 : *
1815 : * We then sort the surviving paths with the cheapest-to-scan first, and
1816 : * for each path, consider using that path alone as the basis for a bitmap
1817 : * scan. Then we consider bitmap AND scans formed from that path plus
1818 : * each subsequent (higher-cost) path, adding on a subsequent path if it
1819 : * results in a reduction in the estimated total scan cost. This means we
1820 : * consider about O(N^2) rather than O(2^N) path combinations, which is
1821 : * quite tolerable, especially given than N is usually reasonably small
1822 : * because of the prefiltering step. The cheapest of these is returned.
1823 : *
1824 : * We will only consider AND combinations in which no two indexes use the
1825 : * same WHERE clause. This is a bit of a kluge: it's needed because
1826 : * costsize.c and clausesel.c aren't very smart about redundant clauses.
1827 : * They will usually double-count the redundant clauses, producing a
1828 : * too-small selectivity that makes a redundant AND step look like it
1829 : * reduces the total cost. Perhaps someday that code will be smarter and
1830 : * we can remove this limitation. (But note that this also defends
1831 : * against flat-out duplicate input paths, which can happen because
1832 : * match_join_clauses_to_index will find the same OR join clauses that
1833 : * extract_restriction_or_clauses has pulled OR restriction clauses out
1834 : * of.)
1835 : *
1836 : * For the same reason, we reject AND combinations in which an index
1837 : * predicate clause duplicates another clause. Here we find it necessary
1838 : * to be even stricter: we'll reject a partial index if any of its
1839 : * predicate clauses are implied by the set of WHERE clauses and predicate
1840 : * clauses used so far. This covers cases such as a condition "x = 42"
1841 : * used with a plain index, followed by a clauseless scan of a partial
1842 : * index "WHERE x >= 40 AND x < 50". The partial index has been accepted
1843 : * only because "x = 42" was present, and so allowing it would partially
1844 : * double-count selectivity. (We could use predicate_implied_by on
1845 : * regular qual clauses too, to have a more intelligent, but much more
1846 : * expensive, check for redundancy --- but in most cases simple equality
1847 : * seems to suffice.)
1848 : */
1849 :
1850 : /*
1851 : * Extract clause usage info and detect any paths that use exactly the
1852 : * same set of clauses; keep only the cheapest-to-scan of any such groups.
1853 : * The surviving paths are put into an array for qsort'ing.
1854 : */
1855 67071 : pathinfoarray = palloc_array(PathClauseUsage *, npaths);
1856 67071 : clauselist = NIL;
1857 67071 : npaths = 0;
1858 224257 : foreach(l, paths)
1859 : {
1860 157186 : Path *ipath = (Path *) lfirst(l);
1861 :
1862 157186 : pathinfo = classify_index_clause_usage(ipath, &clauselist);
1863 :
1864 : /* If it's unclassifiable, treat it as distinct from all others */
1865 157186 : if (pathinfo->unclassifiable)
1866 : {
1867 0 : pathinfoarray[npaths++] = pathinfo;
1868 0 : continue;
1869 : }
1870 :
1871 252100 : for (i = 0; i < npaths; i++)
1872 : {
1873 228170 : if (!pathinfoarray[i]->unclassifiable &&
1874 114085 : bms_equal(pathinfo->clauseids, pathinfoarray[i]->clauseids))
1875 19171 : break;
1876 : }
1877 157186 : if (i < npaths)
1878 : {
1879 : /* duplicate clauseids, keep the cheaper one */
1880 : Cost ncost;
1881 : Cost ocost;
1882 : Selectivity nselec;
1883 : Selectivity oselec;
1884 :
1885 19171 : cost_bitmap_tree_node(pathinfo->path, &ncost, &nselec);
1886 19171 : cost_bitmap_tree_node(pathinfoarray[i]->path, &ocost, &oselec);
1887 19171 : if (ncost < ocost)
1888 2719 : pathinfoarray[i] = pathinfo;
1889 : }
1890 : else
1891 : {
1892 : /* not duplicate clauseids, add to array */
1893 138015 : pathinfoarray[npaths++] = pathinfo;
1894 : }
1895 : }
1896 :
1897 : /* If only one surviving path, we're done */
1898 67071 : if (npaths == 1)
1899 11751 : return pathinfoarray[0]->path;
1900 :
1901 : /* Sort the surviving paths by index access cost */
1902 55320 : qsort(pathinfoarray, npaths, sizeof(PathClauseUsage *),
1903 : path_usage_comparator);
1904 :
1905 : /*
1906 : * For each surviving index, consider it as an "AND group leader", and see
1907 : * whether adding on any of the later indexes results in an AND path with
1908 : * cheaper total cost than before. Then take the cheapest AND group.
1909 : *
1910 : * Note: paths that are either clauseless or unclassifiable will have
1911 : * empty clauseids, so that they will not be rejected by the clauseids
1912 : * filter here, nor will they cause later paths to be rejected by it.
1913 : */
1914 181584 : for (i = 0; i < npaths; i++)
1915 : {
1916 : Cost costsofar;
1917 : List *qualsofar;
1918 : Bitmapset *clauseidsofar;
1919 :
1920 126264 : pathinfo = pathinfoarray[i];
1921 126264 : paths = list_make1(pathinfo->path);
1922 126264 : costsofar = bitmap_scan_cost_est(root, rel, pathinfo->path);
1923 126264 : qualsofar = list_concat_copy(pathinfo->quals, pathinfo->preds);
1924 126264 : clauseidsofar = bms_copy(pathinfo->clauseids);
1925 :
1926 213189 : for (j = i + 1; j < npaths; j++)
1927 : {
1928 : Cost newcost;
1929 :
1930 86925 : pathinfo = pathinfoarray[j];
1931 : /* Check for redundancy */
1932 86925 : if (bms_overlap(pathinfo->clauseids, clauseidsofar))
1933 45371 : continue; /* consider it redundant */
1934 41554 : if (pathinfo->preds)
1935 : {
1936 20 : bool redundant = false;
1937 :
1938 : /* we check each predicate clause separately */
1939 20 : foreach(l, pathinfo->preds)
1940 : {
1941 20 : Node *np = (Node *) lfirst(l);
1942 :
1943 20 : if (predicate_implied_by(list_make1(np), qualsofar, false))
1944 : {
1945 20 : redundant = true;
1946 20 : break; /* out of inner foreach loop */
1947 : }
1948 : }
1949 20 : if (redundant)
1950 20 : continue;
1951 : }
1952 : /* tentatively add new path to paths, so we can estimate cost */
1953 41534 : paths = lappend(paths, pathinfo->path);
1954 41534 : newcost = bitmap_and_cost_est(root, rel, paths);
1955 41534 : if (newcost < costsofar)
1956 : {
1957 : /* keep new path in paths, update subsidiary variables */
1958 201 : costsofar = newcost;
1959 201 : qualsofar = list_concat(qualsofar, pathinfo->quals);
1960 201 : qualsofar = list_concat(qualsofar, pathinfo->preds);
1961 201 : clauseidsofar = bms_add_members(clauseidsofar,
1962 201 : pathinfo->clauseids);
1963 : }
1964 : else
1965 : {
1966 : /* reject new path, remove it from paths list */
1967 41333 : paths = list_truncate(paths, list_length(paths) - 1);
1968 : }
1969 : }
1970 :
1971 : /* Keep the cheapest AND-group (or singleton) */
1972 126264 : if (i == 0 || costsofar < bestcost)
1973 : {
1974 60326 : bestpaths = paths;
1975 60326 : bestcost = costsofar;
1976 : }
1977 :
1978 : /* some easy cleanup (we don't try real hard though) */
1979 126264 : list_free(qualsofar);
1980 : }
1981 :
1982 55320 : if (list_length(bestpaths) == 1)
1983 55142 : return (Path *) linitial(bestpaths); /* no need for AND */
1984 178 : return (Path *) create_bitmap_and_path(root, rel, bestpaths);
1985 : }
1986 :
1987 : /* qsort comparator to sort in increasing index access cost order */
1988 : static int
1989 77621 : path_usage_comparator(const void *a, const void *b)
1990 : {
1991 77621 : PathClauseUsage *pa = *(PathClauseUsage *const *) a;
1992 77621 : PathClauseUsage *pb = *(PathClauseUsage *const *) b;
1993 : Cost acost;
1994 : Cost bcost;
1995 : Selectivity aselec;
1996 : Selectivity bselec;
1997 :
1998 77621 : cost_bitmap_tree_node(pa->path, &acost, &aselec);
1999 77621 : cost_bitmap_tree_node(pb->path, &bcost, &bselec);
2000 :
2001 : /*
2002 : * If costs are the same, sort by selectivity.
2003 : */
2004 77621 : if (acost < bcost)
2005 51447 : return -1;
2006 26174 : if (acost > bcost)
2007 16263 : return 1;
2008 :
2009 9911 : if (aselec < bselec)
2010 4418 : return -1;
2011 5493 : if (aselec > bselec)
2012 698 : return 1;
2013 :
2014 4795 : return 0;
2015 : }
2016 :
2017 : /*
2018 : * Estimate the cost of actually executing a bitmap scan with a single
2019 : * index path (which could be a BitmapAnd or BitmapOr node).
2020 : */
2021 : static Cost
2022 167798 : bitmap_scan_cost_est(PlannerInfo *root, RelOptInfo *rel, Path *ipath)
2023 : {
2024 : BitmapHeapPath bpath;
2025 :
2026 : /* Set up a dummy BitmapHeapPath */
2027 167798 : bpath.path.type = T_BitmapHeapPath;
2028 167798 : bpath.path.pathtype = T_BitmapHeapScan;
2029 167798 : bpath.path.parent = rel;
2030 167798 : bpath.path.pathtarget = rel->reltarget;
2031 167798 : bpath.path.param_info = ipath->param_info;
2032 167798 : bpath.path.pathkeys = NIL;
2033 167798 : bpath.bitmapqual = ipath;
2034 :
2035 : /*
2036 : * Check the cost of temporary path without considering parallelism.
2037 : * Parallel bitmap heap path will be considered at later stage.
2038 : */
2039 167798 : bpath.path.parallel_workers = 0;
2040 :
2041 : /* Now we can do cost_bitmap_heap_scan */
2042 167798 : cost_bitmap_heap_scan(&bpath.path, root, rel,
2043 : bpath.path.param_info,
2044 : ipath,
2045 : get_loop_count(root, rel->relid,
2046 167798 : PATH_REQ_OUTER(ipath)));
2047 :
2048 167798 : return bpath.path.total_cost;
2049 : }
2050 :
2051 : /*
2052 : * Estimate the cost of actually executing a BitmapAnd scan with the given
2053 : * inputs.
2054 : */
2055 : static Cost
2056 41534 : bitmap_and_cost_est(PlannerInfo *root, RelOptInfo *rel, List *paths)
2057 : {
2058 : BitmapAndPath *apath;
2059 :
2060 : /*
2061 : * Might as well build a real BitmapAndPath here, as the work is slightly
2062 : * too complicated to be worth repeating just to save one palloc.
2063 : */
2064 41534 : apath = create_bitmap_and_path(root, rel, paths);
2065 :
2066 41534 : return bitmap_scan_cost_est(root, rel, (Path *) apath);
2067 : }
2068 :
2069 :
2070 : /*
2071 : * classify_index_clause_usage
2072 : * Construct a PathClauseUsage struct describing the WHERE clauses and
2073 : * index predicate clauses used by the given indexscan path.
2074 : * We consider two clauses the same if they are equal().
2075 : *
2076 : * At some point we might want to migrate this info into the Path data
2077 : * structure proper, but for the moment it's only needed within
2078 : * choose_bitmap_and().
2079 : *
2080 : * *clauselist is used and expanded as needed to identify all the distinct
2081 : * clauses seen across successive calls. Caller must initialize it to NIL
2082 : * before first call of a set.
2083 : */
2084 : static PathClauseUsage *
2085 157186 : classify_index_clause_usage(Path *path, List **clauselist)
2086 : {
2087 : PathClauseUsage *result;
2088 : Bitmapset *clauseids;
2089 : ListCell *lc;
2090 :
2091 157186 : result = palloc_object(PathClauseUsage);
2092 157186 : result->path = path;
2093 :
2094 : /* Recursively find the quals and preds used by the path */
2095 157186 : result->quals = NIL;
2096 157186 : result->preds = NIL;
2097 157186 : find_indexpath_quals(path, &result->quals, &result->preds);
2098 :
2099 : /*
2100 : * Some machine-generated queries have outlandish numbers of qual clauses.
2101 : * To avoid getting into O(N^2) behavior even in this preliminary
2102 : * classification step, we want to limit the number of entries we can
2103 : * accumulate in *clauselist. Treat any path with more than 100 quals +
2104 : * preds as unclassifiable, which will cause calling code to consider it
2105 : * distinct from all other paths.
2106 : */
2107 157186 : if (list_length(result->quals) + list_length(result->preds) > 100)
2108 : {
2109 0 : result->clauseids = NULL;
2110 0 : result->unclassifiable = true;
2111 0 : return result;
2112 : }
2113 :
2114 : /* Build up a bitmapset representing the quals and preds */
2115 157186 : clauseids = NULL;
2116 360430 : foreach(lc, result->quals)
2117 : {
2118 203244 : Node *node = (Node *) lfirst(lc);
2119 :
2120 203244 : clauseids = bms_add_member(clauseids,
2121 : find_list_position(node, clauselist));
2122 : }
2123 157431 : foreach(lc, result->preds)
2124 : {
2125 245 : Node *node = (Node *) lfirst(lc);
2126 :
2127 245 : clauseids = bms_add_member(clauseids,
2128 : find_list_position(node, clauselist));
2129 : }
2130 157186 : result->clauseids = clauseids;
2131 157186 : result->unclassifiable = false;
2132 :
2133 157186 : return result;
2134 : }
2135 :
2136 :
2137 : /*
2138 : * find_indexpath_quals
2139 : *
2140 : * Given the Path structure for a plain or bitmap indexscan, extract lists
2141 : * of all the index clauses and index predicate conditions used in the Path.
2142 : * These are appended to the initial contents of *quals and *preds (hence
2143 : * caller should initialize those to NIL).
2144 : *
2145 : * Note we are not trying to produce an accurate representation of the AND/OR
2146 : * semantics of the Path, but just find out all the base conditions used.
2147 : *
2148 : * The result lists contain pointers to the expressions used in the Path,
2149 : * but all the list cells are freshly built, so it's safe to destructively
2150 : * modify the lists (eg, by concat'ing with other lists).
2151 : */
2152 : static void
2153 160671 : find_indexpath_quals(Path *bitmapqual, List **quals, List **preds)
2154 : {
2155 160671 : if (IsA(bitmapqual, BitmapAndPath))
2156 : {
2157 0 : BitmapAndPath *apath = (BitmapAndPath *) bitmapqual;
2158 : ListCell *l;
2159 :
2160 0 : foreach(l, apath->bitmapquals)
2161 : {
2162 0 : find_indexpath_quals((Path *) lfirst(l), quals, preds);
2163 : }
2164 : }
2165 160671 : else if (IsA(bitmapqual, BitmapOrPath))
2166 : {
2167 2823 : BitmapOrPath *opath = (BitmapOrPath *) bitmapqual;
2168 : ListCell *l;
2169 :
2170 6308 : foreach(l, opath->bitmapquals)
2171 : {
2172 3485 : find_indexpath_quals((Path *) lfirst(l), quals, preds);
2173 : }
2174 : }
2175 157848 : else if (IsA(bitmapqual, IndexPath))
2176 : {
2177 157848 : IndexPath *ipath = (IndexPath *) bitmapqual;
2178 : ListCell *l;
2179 :
2180 361092 : foreach(l, ipath->indexclauses)
2181 : {
2182 203244 : IndexClause *iclause = (IndexClause *) lfirst(l);
2183 :
2184 203244 : *quals = lappend(*quals, iclause->rinfo->clause);
2185 : }
2186 157848 : *preds = list_concat(*preds, ipath->indexinfo->indpred);
2187 : }
2188 : else
2189 0 : elog(ERROR, "unrecognized node type: %d", nodeTag(bitmapqual));
2190 160671 : }
2191 :
2192 :
2193 : /*
2194 : * find_list_position
2195 : * Return the given node's position (counting from 0) in the given
2196 : * list of nodes. If it's not equal() to any existing list member,
2197 : * add it at the end, and return that position.
2198 : */
2199 : static int
2200 203489 : find_list_position(Node *node, List **nodelist)
2201 : {
2202 : int i;
2203 : ListCell *lc;
2204 :
2205 203489 : i = 0;
2206 317089 : foreach(lc, *nodelist)
2207 : {
2208 180404 : Node *oldnode = (Node *) lfirst(lc);
2209 :
2210 180404 : if (equal(node, oldnode))
2211 66804 : return i;
2212 113600 : i++;
2213 : }
2214 :
2215 136685 : *nodelist = lappend(*nodelist, node);
2216 :
2217 136685 : return i;
2218 : }
2219 :
2220 :
2221 : /*
2222 : * check_index_only
2223 : * Determine whether an index-only scan is possible for this index.
2224 : */
2225 : static bool
2226 697217 : check_index_only(RelOptInfo *rel, IndexOptInfo *index)
2227 : {
2228 : bool result;
2229 697217 : Bitmapset *attrs_used = NULL;
2230 697217 : Bitmapset *index_canreturn_attrs = NULL;
2231 : ListCell *lc;
2232 : int i;
2233 :
2234 : /* If we're not allowed to consider index-only scans, give up now */
2235 697217 : if ((rel->pgs_mask & PGS_CONSIDER_INDEXONLY) == 0)
2236 84045 : return false;
2237 :
2238 : /*
2239 : * Check that all needed attributes of the relation are available from the
2240 : * index.
2241 : */
2242 :
2243 : /*
2244 : * First, identify all the attributes needed for joins or final output.
2245 : * Note: we must look at rel's targetlist, not the attr_needed data,
2246 : * because attr_needed isn't computed for inheritance child rels.
2247 : */
2248 613172 : pull_varattnos((Node *) rel->reltarget->exprs, rel->relid, &attrs_used);
2249 :
2250 : /*
2251 : * Add all the attributes used by restriction clauses; but consider only
2252 : * those clauses not implied by the index predicate, since ones that are
2253 : * so implied don't need to be checked explicitly in the plan.
2254 : *
2255 : * Note: attributes used only in index quals would not be needed at
2256 : * runtime either, if we are certain that the index is not lossy. However
2257 : * it'd be complicated to account for that accurately, and it doesn't
2258 : * matter in most cases, since we'd conclude that such attributes are
2259 : * available from the index anyway.
2260 : */
2261 1260321 : foreach(lc, index->indrestrictinfo)
2262 : {
2263 647149 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
2264 :
2265 647149 : pull_varattnos((Node *) rinfo->clause, rel->relid, &attrs_used);
2266 : }
2267 :
2268 : /*
2269 : * Construct a bitmapset of columns that the index can return back in an
2270 : * index-only scan.
2271 : */
2272 1746062 : for (i = 0; i < index->ncolumns; i++)
2273 : {
2274 1132890 : int attno = index->indexkeys[i];
2275 :
2276 : /*
2277 : * For the moment, we just ignore index expressions. It might be nice
2278 : * to do something with them, later.
2279 : */
2280 1132890 : if (attno == 0)
2281 2208 : continue;
2282 :
2283 1130682 : if (index->canreturn[i])
2284 : index_canreturn_attrs =
2285 924619 : bms_add_member(index_canreturn_attrs,
2286 : attno - FirstLowInvalidHeapAttributeNumber);
2287 : }
2288 :
2289 : /* Do we have all the necessary attributes? */
2290 613172 : result = bms_is_subset(attrs_used, index_canreturn_attrs);
2291 :
2292 613172 : bms_free(attrs_used);
2293 613172 : bms_free(index_canreturn_attrs);
2294 :
2295 613172 : return result;
2296 : }
2297 :
2298 : /*
2299 : * get_loop_count
2300 : * Choose the loop count estimate to use for costing a parameterized path
2301 : * with the given set of outer relids.
2302 : *
2303 : * Since we produce parameterized paths before we've begun to generate join
2304 : * relations, it's impossible to predict exactly how many times a parameterized
2305 : * path will be iterated; we don't know the size of the relation that will be
2306 : * on the outside of the nestloop. However, we should try to account for
2307 : * multiple iterations somehow in costing the path. The heuristic embodied
2308 : * here is to use the rowcount of the smallest other base relation needed in
2309 : * the join clauses used by the path. (We could alternatively consider the
2310 : * largest one, but that seems too optimistic.) This is of course the right
2311 : * answer for single-other-relation cases, and it seems like a reasonable
2312 : * zero-order approximation for multiway-join cases.
2313 : *
2314 : * In addition, we check to see if the other side of each join clause is on
2315 : * the inside of some semijoin that the current relation is on the outside of.
2316 : * If so, the only way that a parameterized path could be used is if the
2317 : * semijoin RHS has been unique-ified, so we should use the number of unique
2318 : * RHS rows rather than using the relation's raw rowcount.
2319 : *
2320 : * Note: for this to work, allpaths.c must establish all baserel size
2321 : * estimates before it begins to compute paths, or at least before it
2322 : * calls create_index_paths().
2323 : */
2324 : static double
2325 993943 : get_loop_count(PlannerInfo *root, Index cur_relid, Relids outer_relids)
2326 : {
2327 : double result;
2328 : int outer_relid;
2329 :
2330 : /* For a non-parameterized path, just return 1.0 quickly */
2331 993943 : if (outer_relids == NULL)
2332 650992 : return 1.0;
2333 :
2334 342951 : result = 0.0;
2335 342951 : outer_relid = -1;
2336 695898 : while ((outer_relid = bms_next_member(outer_relids, outer_relid)) >= 0)
2337 : {
2338 : RelOptInfo *outer_rel;
2339 : double rowcount;
2340 :
2341 : /* Paranoia: ignore bogus relid indexes */
2342 352947 : if (outer_relid >= root->simple_rel_array_size)
2343 0 : continue;
2344 352947 : outer_rel = root->simple_rel_array[outer_relid];
2345 352947 : if (outer_rel == NULL)
2346 175 : continue;
2347 : Assert(outer_rel->relid == outer_relid); /* sanity check on array */
2348 :
2349 : /* Other relation could be proven empty, if so ignore */
2350 352772 : if (IS_DUMMY_REL(outer_rel))
2351 20 : continue;
2352 :
2353 : /* Otherwise, rel's rows estimate should be valid by now */
2354 : Assert(outer_rel->rows > 0);
2355 :
2356 : /* Check to see if rel is on the inside of any semijoins */
2357 352752 : rowcount = adjust_rowcount_for_semijoins(root,
2358 : cur_relid,
2359 : outer_relid,
2360 : outer_rel->rows);
2361 :
2362 : /* Remember smallest row count estimate among the outer rels */
2363 352752 : if (result == 0.0 || result > rowcount)
2364 349025 : result = rowcount;
2365 : }
2366 : /* Return 1.0 if we found no valid relations (shouldn't happen) */
2367 342951 : return (result > 0.0) ? result : 1.0;
2368 : }
2369 :
2370 : /*
2371 : * Check to see if outer_relid is on the inside of any semijoin that cur_relid
2372 : * is on the outside of. If so, replace rowcount with the estimated number of
2373 : * unique rows from the semijoin RHS (assuming that's smaller, which it might
2374 : * not be). The estimate is crude but it's the best we can do at this stage
2375 : * of the proceedings.
2376 : */
2377 : static double
2378 352752 : adjust_rowcount_for_semijoins(PlannerInfo *root,
2379 : Index cur_relid,
2380 : Index outer_relid,
2381 : double rowcount)
2382 : {
2383 : ListCell *lc;
2384 :
2385 524012 : foreach(lc, root->join_info_list)
2386 : {
2387 171260 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(lc);
2388 :
2389 177412 : if (sjinfo->jointype == JOIN_SEMI &&
2390 8485 : bms_is_member(cur_relid, sjinfo->syn_lefthand) &&
2391 2333 : bms_is_member(outer_relid, sjinfo->syn_righthand))
2392 : {
2393 : /* Estimate number of unique-ified rows */
2394 : double nraw;
2395 : double nunique;
2396 :
2397 988 : nraw = approximate_joinrel_size(root, sjinfo->syn_righthand);
2398 988 : nunique = estimate_num_groups(root,
2399 : sjinfo->semi_rhs_exprs,
2400 : nraw,
2401 : NULL,
2402 : NULL);
2403 988 : if (rowcount > nunique)
2404 389 : rowcount = nunique;
2405 : }
2406 : }
2407 352752 : return rowcount;
2408 : }
2409 :
2410 : /*
2411 : * Make an approximate estimate of the size of a joinrel.
2412 : *
2413 : * We don't have enough info at this point to get a good estimate, so we
2414 : * just multiply the base relation sizes together. Fortunately, this is
2415 : * the right answer anyway for the most common case with a single relation
2416 : * on the RHS of a semijoin. Also, estimate_num_groups() has only a weak
2417 : * dependency on its input_rows argument (it basically uses it as a clamp).
2418 : * So we might be able to get a fairly decent end result even with a severe
2419 : * overestimate of the RHS's raw size.
2420 : */
2421 : static double
2422 988 : approximate_joinrel_size(PlannerInfo *root, Relids relids)
2423 : {
2424 988 : double rowcount = 1.0;
2425 : int relid;
2426 :
2427 988 : relid = -1;
2428 2118 : while ((relid = bms_next_member(relids, relid)) >= 0)
2429 : {
2430 : RelOptInfo *rel;
2431 :
2432 : /* Paranoia: ignore bogus relid indexes */
2433 1130 : if (relid >= root->simple_rel_array_size)
2434 0 : continue;
2435 1130 : rel = root->simple_rel_array[relid];
2436 1130 : if (rel == NULL)
2437 0 : continue;
2438 : Assert(rel->relid == relid); /* sanity check on array */
2439 :
2440 : /* Relation could be proven empty, if so ignore */
2441 1130 : if (IS_DUMMY_REL(rel))
2442 0 : continue;
2443 :
2444 : /* Otherwise, rel's rows estimate should be valid by now */
2445 : Assert(rel->rows > 0);
2446 :
2447 : /* Accumulate product */
2448 1130 : rowcount *= rel->rows;
2449 : }
2450 988 : return rowcount;
2451 : }
2452 :
2453 :
2454 : /****************************************************************************
2455 : * ---- ROUTINES TO CHECK QUERY CLAUSES ----
2456 : ****************************************************************************/
2457 :
2458 : /*
2459 : * match_restriction_clauses_to_index
2460 : * Identify restriction clauses for the rel that match the index.
2461 : * Matching clauses are added to *clauseset.
2462 : */
2463 : static void
2464 562213 : match_restriction_clauses_to_index(PlannerInfo *root,
2465 : IndexOptInfo *index,
2466 : IndexClauseSet *clauseset)
2467 : {
2468 : /* We can ignore clauses that are implied by the index predicate */
2469 562213 : match_clauses_to_index(root, index->indrestrictinfo, index, clauseset);
2470 562213 : }
2471 :
2472 : /*
2473 : * match_join_clauses_to_index
2474 : * Identify join clauses for the rel that match the index.
2475 : * Matching clauses are added to *clauseset.
2476 : * Also, add any potentially usable join OR clauses to *joinorclauses.
2477 : * They also might be processed by match_clause_to_index() as a whole.
2478 : */
2479 : static void
2480 562213 : match_join_clauses_to_index(PlannerInfo *root,
2481 : RelOptInfo *rel, IndexOptInfo *index,
2482 : IndexClauseSet *clauseset,
2483 : List **joinorclauses)
2484 : {
2485 : ListCell *lc;
2486 :
2487 : /* Scan the rel's join clauses */
2488 772817 : foreach(lc, rel->joininfo)
2489 : {
2490 210604 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
2491 :
2492 : /* Check if clause can be moved to this rel */
2493 210604 : if (!join_clause_is_movable_to(rinfo, rel))
2494 130772 : continue;
2495 :
2496 : /*
2497 : * Potentially usable, so see if it matches the index or is an OR. Use
2498 : * list_append_unique_ptr() here to avoid possible duplicates when
2499 : * processing the same clauses with different indexes.
2500 : */
2501 79832 : if (restriction_is_or_clause(rinfo))
2502 9636 : *joinorclauses = list_append_unique_ptr(*joinorclauses, rinfo);
2503 :
2504 79832 : match_clause_to_index(root, rinfo, index, clauseset);
2505 : }
2506 562213 : }
2507 :
2508 : /*
2509 : * match_eclass_clauses_to_index
2510 : * Identify EquivalenceClass join clauses for the rel that match the index.
2511 : * Matching clauses are added to *clauseset.
2512 : */
2513 : static void
2514 562213 : match_eclass_clauses_to_index(PlannerInfo *root, IndexOptInfo *index,
2515 : IndexClauseSet *clauseset)
2516 : {
2517 : int indexcol;
2518 :
2519 : /* No work if rel is not in any such ECs */
2520 562213 : if (!index->rel->has_eclass_joins)
2521 314594 : return;
2522 :
2523 638361 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
2524 : {
2525 : ec_member_matches_arg arg;
2526 : List *clauses;
2527 :
2528 : /* Generate clauses, skipping any that join to lateral_referencers */
2529 390742 : arg.index = index;
2530 390742 : arg.indexcol = indexcol;
2531 390742 : clauses = generate_implied_equalities_for_column(root,
2532 : index->rel,
2533 : ec_member_matches_indexcol,
2534 : &arg,
2535 390742 : index->rel->lateral_referencers);
2536 :
2537 : /*
2538 : * We have to check whether the results actually do match the index,
2539 : * since for non-btree indexes the EC's equality operators might not
2540 : * be in the index opclass (cf ec_member_matches_indexcol).
2541 : */
2542 390742 : match_clauses_to_index(root, clauses, index, clauseset);
2543 : }
2544 : }
2545 :
2546 : /*
2547 : * match_clauses_to_index
2548 : * Perform match_clause_to_index() for each clause in a list.
2549 : * Matching clauses are added to *clauseset.
2550 : */
2551 : static void
2552 984560 : match_clauses_to_index(PlannerInfo *root,
2553 : List *clauses,
2554 : IndexOptInfo *index,
2555 : IndexClauseSet *clauseset)
2556 : {
2557 : ListCell *lc;
2558 :
2559 1770224 : foreach(lc, clauses)
2560 : {
2561 785664 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
2562 :
2563 785664 : match_clause_to_index(root, rinfo, index, clauseset);
2564 : }
2565 984560 : }
2566 :
2567 : /*
2568 : * match_clause_to_index
2569 : * Test whether a qual clause can be used with an index.
2570 : *
2571 : * If the clause is usable, add an IndexClause entry for it to the appropriate
2572 : * list in *clauseset. (*clauseset must be initialized to zeroes before first
2573 : * call.)
2574 : *
2575 : * Note: in some circumstances we may find the same RestrictInfos coming from
2576 : * multiple places. Defend against redundant outputs by refusing to add a
2577 : * clause twice (pointer equality should be a good enough check for this).
2578 : *
2579 : * Note: it's possible that a badly-defined index could have multiple matching
2580 : * columns. We always select the first match if so; this avoids scenarios
2581 : * wherein we get an inflated idea of the index's selectivity by using the
2582 : * same clause multiple times with different index columns.
2583 : */
2584 : static void
2585 865496 : match_clause_to_index(PlannerInfo *root,
2586 : RestrictInfo *rinfo,
2587 : IndexOptInfo *index,
2588 : IndexClauseSet *clauseset)
2589 : {
2590 : int indexcol;
2591 :
2592 : /*
2593 : * Never match pseudoconstants to indexes. (Normally a match could not
2594 : * happen anyway, since a pseudoconstant clause couldn't contain a Var,
2595 : * but what if someone builds an expression index on a constant? It's not
2596 : * totally unreasonable to do so with a partial index, either.)
2597 : */
2598 865496 : if (rinfo->pseudoconstant)
2599 6374 : return;
2600 :
2601 : /*
2602 : * If clause can't be used as an indexqual because it must wait till after
2603 : * some lower-security-level restriction clause, reject it.
2604 : */
2605 859122 : if (!restriction_is_securely_promotable(rinfo, index->rel))
2606 435 : return;
2607 :
2608 : /* OK, check each index key column for a match */
2609 1869775 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
2610 : {
2611 : IndexClause *iclause;
2612 : ListCell *lc;
2613 :
2614 : /* Ignore duplicates */
2615 1404323 : foreach(lc, clauseset->indexclauses[indexcol])
2616 : {
2617 60447 : iclause = (IndexClause *) lfirst(lc);
2618 :
2619 60447 : if (iclause->rinfo == rinfo)
2620 0 : return;
2621 : }
2622 :
2623 : /* OK, try to match the clause to the index column */
2624 1343876 : iclause = match_clause_to_indexcol(root,
2625 : rinfo,
2626 : indexcol,
2627 : index);
2628 1343876 : if (iclause)
2629 : {
2630 : /* Success, so record it */
2631 332788 : clauseset->indexclauses[indexcol] =
2632 332788 : lappend(clauseset->indexclauses[indexcol], iclause);
2633 332788 : clauseset->nonempty = true;
2634 332788 : return;
2635 : }
2636 : }
2637 : }
2638 :
2639 : /*
2640 : * match_clause_to_indexcol()
2641 : * Determine whether a restriction clause matches a column of an index,
2642 : * and if so, build an IndexClause node describing the details.
2643 : *
2644 : * To match an index normally, an operator clause:
2645 : *
2646 : * (1) must be in the form (indexkey op const) or (const op indexkey);
2647 : * and
2648 : * (2) must contain an operator which is in the index's operator family
2649 : * for this column; and
2650 : * (3) must match the collation of the index, if collation is relevant.
2651 : *
2652 : * Our definition of "const" is exceedingly liberal: we allow anything that
2653 : * doesn't involve a volatile function or a Var of the index's relation.
2654 : * In particular, Vars belonging to other relations of the query are
2655 : * accepted here, since a clause of that form can be used in a
2656 : * parameterized indexscan. It's the responsibility of higher code levels
2657 : * to manage restriction and join clauses appropriately.
2658 : *
2659 : * Note: we do need to check for Vars of the index's relation on the
2660 : * "const" side of the clause, since clauses like (a.f1 OP (b.f2 OP a.f3))
2661 : * are not processable by a parameterized indexscan on a.f1, whereas
2662 : * something like (a.f1 OP (b.f2 OP c.f3)) is.
2663 : *
2664 : * Presently, the executor can only deal with indexquals that have the
2665 : * indexkey on the left, so we can only use clauses that have the indexkey
2666 : * on the right if we can commute the clause to put the key on the left.
2667 : * We handle that by generating an IndexClause with the correctly-commuted
2668 : * opclause as a derived indexqual.
2669 : *
2670 : * If the index has a collation, the clause must have the same collation.
2671 : * For collation-less indexes, we assume it doesn't matter; this is
2672 : * necessary for cases like "hstore ? text", wherein hstore's operators
2673 : * don't care about collation but the clause will get marked with a
2674 : * collation anyway because of the text argument. (This logic is
2675 : * embodied in the macro IndexCollMatchesExprColl.)
2676 : *
2677 : * It is also possible to match RowCompareExpr clauses to indexes (but
2678 : * currently, only btree indexes handle this).
2679 : *
2680 : * It is also possible to match ScalarArrayOpExpr clauses to indexes, when
2681 : * the clause is of the form "indexkey op ANY (arrayconst)".
2682 : *
2683 : * It is also possible to match a list of OR clauses if it might be
2684 : * transformed into a single ScalarArrayOpExpr clause. On success,
2685 : * the returning index clause will contain a transformed clause.
2686 : *
2687 : * For boolean indexes, it is also possible to match the clause directly
2688 : * to the indexkey; or perhaps the clause is (NOT indexkey).
2689 : *
2690 : * And, last but not least, some operators and functions can be processed
2691 : * to derive (typically lossy) indexquals from a clause that isn't in
2692 : * itself indexable. If we see that any operand of an OpExpr or FuncExpr
2693 : * matches the index key, and the function has a planner support function
2694 : * attached to it, we'll invoke the support function to see if such an
2695 : * indexqual can be built.
2696 : *
2697 : * 'rinfo' is the clause to be tested (as a RestrictInfo node).
2698 : * 'indexcol' is a column number of 'index' (counting from 0).
2699 : * 'index' is the index of interest.
2700 : *
2701 : * Returns an IndexClause if the clause can be used with this index key,
2702 : * or NULL if not.
2703 : *
2704 : * NOTE: This routine always returns NULL if the clause is an AND clause.
2705 : * Higher-level routines deal with OR and AND clauses. OR clause can be
2706 : * matched as a whole by match_orclause_to_indexcol() though.
2707 : */
2708 : static IndexClause *
2709 1343876 : match_clause_to_indexcol(PlannerInfo *root,
2710 : RestrictInfo *rinfo,
2711 : int indexcol,
2712 : IndexOptInfo *index)
2713 : {
2714 : IndexClause *iclause;
2715 1343876 : Expr *clause = rinfo->clause;
2716 : Oid opfamily;
2717 :
2718 : Assert(indexcol < index->nkeycolumns);
2719 :
2720 : /*
2721 : * Historically this code has coped with NULL clauses. That's probably
2722 : * not possible anymore, but we might as well continue to cope.
2723 : */
2724 1343876 : if (clause == NULL)
2725 0 : return NULL;
2726 :
2727 : /* First check for boolean-index cases. */
2728 1343876 : opfamily = index->opfamily[indexcol];
2729 1343876 : if (IsBooleanOpfamily(opfamily))
2730 : {
2731 616 : iclause = match_boolean_index_clause(root, rinfo, indexcol, index);
2732 616 : if (iclause)
2733 351 : return iclause;
2734 : }
2735 :
2736 : /*
2737 : * Clause must be an opclause, funcclause, ScalarArrayOpExpr,
2738 : * RowCompareExpr, or OR-clause that could be converted to SAOP. Or, if
2739 : * the index supports it, we can handle IS NULL/NOT NULL clauses.
2740 : */
2741 1343525 : if (IsA(clause, OpExpr))
2742 : {
2743 1102890 : return match_opclause_to_indexcol(root, rinfo, indexcol, index);
2744 : }
2745 240635 : else if (IsA(clause, FuncExpr))
2746 : {
2747 27074 : return match_funcclause_to_indexcol(root, rinfo, indexcol, index);
2748 : }
2749 213561 : else if (IsA(clause, ScalarArrayOpExpr))
2750 : {
2751 60006 : return match_saopclause_to_indexcol(root, rinfo, indexcol, index);
2752 : }
2753 153555 : else if (IsA(clause, RowCompareExpr))
2754 : {
2755 420 : return match_rowcompare_to_indexcol(root, rinfo, indexcol, index);
2756 : }
2757 153135 : else if (restriction_is_or_clause(rinfo))
2758 : {
2759 40352 : return match_orclause_to_indexcol(root, rinfo, indexcol, index);
2760 : }
2761 112783 : else if (index->amsearchnulls && IsA(clause, NullTest))
2762 : {
2763 11302 : NullTest *nt = (NullTest *) clause;
2764 :
2765 22604 : if (!nt->argisrow &&
2766 11302 : match_index_to_operand((Node *) nt->arg, indexcol, index))
2767 : {
2768 1212 : iclause = makeNode(IndexClause);
2769 1212 : iclause->rinfo = rinfo;
2770 1212 : iclause->indexquals = list_make1(rinfo);
2771 1212 : iclause->lossy = false;
2772 1212 : iclause->indexcol = indexcol;
2773 1212 : iclause->indexcols = NIL;
2774 1212 : return iclause;
2775 : }
2776 : }
2777 :
2778 111571 : return NULL;
2779 : }
2780 :
2781 : /*
2782 : * IsBooleanOpfamily
2783 : * Detect whether an opfamily supports boolean equality as an operator.
2784 : *
2785 : * If the opfamily OID is in the range of built-in objects, we can rely
2786 : * on hard-wired knowledge of which built-in opfamilies support this.
2787 : * For extension opfamilies, there's no choice but to do a catcache lookup.
2788 : */
2789 : static bool
2790 1854098 : IsBooleanOpfamily(Oid opfamily)
2791 : {
2792 1854098 : if (opfamily < FirstNormalObjectId)
2793 1852263 : return IsBuiltinBooleanOpfamily(opfamily);
2794 : else
2795 1835 : return op_in_opfamily(BooleanEqualOperator, opfamily);
2796 : }
2797 :
2798 : /*
2799 : * match_boolean_index_clause
2800 : * Recognize restriction clauses that can be matched to a boolean index.
2801 : *
2802 : * The idea here is that, for an index on a boolean column that supports the
2803 : * BooleanEqualOperator, we can transform a plain reference to the indexkey
2804 : * into "indexkey = true", or "NOT indexkey" into "indexkey = false", etc,
2805 : * so as to make the expression indexable using the index's "=" operator.
2806 : * Since Postgres 8.1, we must do this because constant simplification does
2807 : * the reverse transformation; without this code there'd be no way to use
2808 : * such an index at all.
2809 : *
2810 : * This should be called only when IsBooleanOpfamily() recognizes the
2811 : * index's operator family. We check to see if the clause matches the
2812 : * index's key, and if so, build a suitable IndexClause.
2813 : */
2814 : static IndexClause *
2815 1914 : match_boolean_index_clause(PlannerInfo *root,
2816 : RestrictInfo *rinfo,
2817 : int indexcol,
2818 : IndexOptInfo *index)
2819 : {
2820 1914 : Node *clause = (Node *) rinfo->clause;
2821 1914 : Expr *op = NULL;
2822 :
2823 : /* Direct match? */
2824 1914 : if (match_index_to_operand(clause, indexcol, index))
2825 : {
2826 : /* convert to indexkey = TRUE */
2827 205 : op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2828 : (Expr *) clause,
2829 205 : (Expr *) makeBoolConst(true, false),
2830 : InvalidOid, InvalidOid);
2831 : }
2832 : /* NOT clause? */
2833 1709 : else if (is_notclause(clause))
2834 : {
2835 1374 : Node *arg = (Node *) get_notclausearg((Expr *) clause);
2836 :
2837 1374 : if (match_index_to_operand(arg, indexcol, index))
2838 : {
2839 : /* convert to indexkey = FALSE */
2840 1374 : op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2841 : (Expr *) arg,
2842 1374 : (Expr *) makeBoolConst(false, false),
2843 : InvalidOid, InvalidOid);
2844 : }
2845 : }
2846 :
2847 : /*
2848 : * Since we only consider clauses at top level of WHERE, we can convert
2849 : * indexkey IS TRUE and indexkey IS FALSE to index searches as well. The
2850 : * different meaning for NULL isn't important.
2851 : */
2852 335 : else if (clause && IsA(clause, BooleanTest))
2853 : {
2854 50 : BooleanTest *btest = (BooleanTest *) clause;
2855 50 : Node *arg = (Node *) btest->arg;
2856 :
2857 75 : if (btest->booltesttype == IS_TRUE &&
2858 25 : match_index_to_operand(arg, indexcol, index))
2859 : {
2860 : /* convert to indexkey = TRUE */
2861 25 : op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2862 : (Expr *) arg,
2863 25 : (Expr *) makeBoolConst(true, false),
2864 : InvalidOid, InvalidOid);
2865 : }
2866 40 : else if (btest->booltesttype == IS_FALSE &&
2867 15 : match_index_to_operand(arg, indexcol, index))
2868 : {
2869 : /* convert to indexkey = FALSE */
2870 15 : op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2871 : (Expr *) arg,
2872 15 : (Expr *) makeBoolConst(false, false),
2873 : InvalidOid, InvalidOid);
2874 : }
2875 : }
2876 :
2877 : /*
2878 : * If we successfully made an operator clause from the given qual, we must
2879 : * wrap it in an IndexClause. It's not lossy.
2880 : */
2881 1914 : if (op)
2882 : {
2883 1619 : IndexClause *iclause = makeNode(IndexClause);
2884 :
2885 1619 : iclause->rinfo = rinfo;
2886 1619 : iclause->indexquals = list_make1(make_simple_restrictinfo(root, op));
2887 1619 : iclause->lossy = false;
2888 1619 : iclause->indexcol = indexcol;
2889 1619 : iclause->indexcols = NIL;
2890 1619 : return iclause;
2891 : }
2892 :
2893 295 : return NULL;
2894 : }
2895 :
2896 : /*
2897 : * match_opclause_to_indexcol()
2898 : * Handles the OpExpr case for match_clause_to_indexcol(),
2899 : * which see for comments.
2900 : */
2901 : static IndexClause *
2902 1102890 : match_opclause_to_indexcol(PlannerInfo *root,
2903 : RestrictInfo *rinfo,
2904 : int indexcol,
2905 : IndexOptInfo *index)
2906 : {
2907 : IndexClause *iclause;
2908 1102890 : OpExpr *clause = (OpExpr *) rinfo->clause;
2909 : Node *leftop,
2910 : *rightop;
2911 : Oid expr_op;
2912 : Oid expr_coll;
2913 : Index index_relid;
2914 : Oid opfamily;
2915 : Oid idxcollation;
2916 :
2917 : /*
2918 : * Only binary operators need apply. (In theory, a planner support
2919 : * function could do something with a unary operator, but it seems
2920 : * unlikely to be worth the cycles to check.)
2921 : */
2922 1102890 : if (list_length(clause->args) != 2)
2923 0 : return NULL;
2924 :
2925 1102890 : leftop = (Node *) linitial(clause->args);
2926 1102890 : rightop = (Node *) lsecond(clause->args);
2927 1102890 : expr_op = clause->opno;
2928 1102890 : expr_coll = clause->inputcollid;
2929 :
2930 1102890 : index_relid = index->rel->relid;
2931 1102890 : opfamily = index->opfamily[indexcol];
2932 1102890 : idxcollation = index->indexcollations[indexcol];
2933 :
2934 : /*
2935 : * Check for clauses of the form: (indexkey operator constant) or
2936 : * (constant operator indexkey). See match_clause_to_indexcol's notes
2937 : * about const-ness.
2938 : *
2939 : * Note that we don't ask the support function about clauses that don't
2940 : * have one of these forms. Again, in principle it might be possible to
2941 : * do something, but it seems unlikely to be worth the cycles to check.
2942 : */
2943 1102890 : if (match_index_to_operand(leftop, indexcol, index) &&
2944 274416 : !bms_is_member(index_relid, rinfo->right_relids) &&
2945 274265 : !contain_volatile_functions(rightop))
2946 : {
2947 542777 : if (IndexCollMatchesExprColl(idxcollation, expr_coll) &&
2948 268512 : op_in_opfamily(expr_op, opfamily))
2949 : {
2950 262974 : iclause = makeNode(IndexClause);
2951 262974 : iclause->rinfo = rinfo;
2952 262974 : iclause->indexquals = list_make1(rinfo);
2953 262974 : iclause->lossy = false;
2954 262974 : iclause->indexcol = indexcol;
2955 262974 : iclause->indexcols = NIL;
2956 262974 : return iclause;
2957 : }
2958 :
2959 : /*
2960 : * If we didn't find a member of the index's opfamily, try the support
2961 : * function for the operator's underlying function.
2962 : */
2963 11291 : set_opfuncid(clause); /* make sure we have opfuncid */
2964 11291 : return get_index_clause_from_support(root,
2965 : rinfo,
2966 : clause->opfuncid,
2967 : 0, /* indexarg on left */
2968 : indexcol,
2969 : index);
2970 : }
2971 :
2972 828625 : if (match_index_to_operand(rightop, indexcol, index) &&
2973 59120 : !bms_is_member(index_relid, rinfo->left_relids) &&
2974 59015 : !contain_volatile_functions(leftop))
2975 : {
2976 59015 : if (IndexCollMatchesExprColl(idxcollation, expr_coll))
2977 : {
2978 59005 : Oid comm_op = get_commutator(expr_op);
2979 :
2980 118010 : if (OidIsValid(comm_op) &&
2981 59005 : op_in_opfamily(comm_op, opfamily))
2982 : {
2983 : RestrictInfo *commrinfo;
2984 :
2985 : /* Build a commuted OpExpr and RestrictInfo */
2986 58636 : commrinfo = commute_restrictinfo(rinfo, comm_op);
2987 :
2988 : /* Make an IndexClause showing that as a derived qual */
2989 58636 : iclause = makeNode(IndexClause);
2990 58636 : iclause->rinfo = rinfo;
2991 58636 : iclause->indexquals = list_make1(commrinfo);
2992 58636 : iclause->lossy = false;
2993 58636 : iclause->indexcol = indexcol;
2994 58636 : iclause->indexcols = NIL;
2995 58636 : return iclause;
2996 : }
2997 : }
2998 :
2999 : /*
3000 : * If we didn't find a member of the index's opfamily, try the support
3001 : * function for the operator's underlying function.
3002 : */
3003 379 : set_opfuncid(clause); /* make sure we have opfuncid */
3004 379 : return get_index_clause_from_support(root,
3005 : rinfo,
3006 : clause->opfuncid,
3007 : 1, /* indexarg on right */
3008 : indexcol,
3009 : index);
3010 : }
3011 :
3012 769610 : return NULL;
3013 : }
3014 :
3015 : /*
3016 : * match_funcclause_to_indexcol()
3017 : * Handles the FuncExpr case for match_clause_to_indexcol(),
3018 : * which see for comments.
3019 : */
3020 : static IndexClause *
3021 27074 : match_funcclause_to_indexcol(PlannerInfo *root,
3022 : RestrictInfo *rinfo,
3023 : int indexcol,
3024 : IndexOptInfo *index)
3025 : {
3026 27074 : FuncExpr *clause = (FuncExpr *) rinfo->clause;
3027 : int indexarg;
3028 : ListCell *lc;
3029 :
3030 : /*
3031 : * We have no built-in intelligence about function clauses, but if there's
3032 : * a planner support function, it might be able to do something. But, to
3033 : * cut down on wasted planning cycles, only call the support function if
3034 : * at least one argument matches the target index column.
3035 : *
3036 : * Note that we don't insist on the other arguments being pseudoconstants;
3037 : * the support function has to check that. This is to allow cases where
3038 : * only some of the other arguments need to be included in the indexqual.
3039 : */
3040 27074 : indexarg = 0;
3041 59548 : foreach(lc, clause->args)
3042 : {
3043 37200 : Node *op = (Node *) lfirst(lc);
3044 :
3045 37200 : if (match_index_to_operand(op, indexcol, index))
3046 : {
3047 4726 : return get_index_clause_from_support(root,
3048 : rinfo,
3049 : clause->funcid,
3050 : indexarg,
3051 : indexcol,
3052 : index);
3053 : }
3054 :
3055 32474 : indexarg++;
3056 : }
3057 :
3058 22348 : return NULL;
3059 : }
3060 :
3061 : /*
3062 : * get_index_clause_from_support()
3063 : * If the function has a planner support function, try to construct
3064 : * an IndexClause using indexquals created by the support function.
3065 : */
3066 : static IndexClause *
3067 16396 : get_index_clause_from_support(PlannerInfo *root,
3068 : RestrictInfo *rinfo,
3069 : Oid funcid,
3070 : int indexarg,
3071 : int indexcol,
3072 : IndexOptInfo *index)
3073 : {
3074 16396 : Oid prosupport = get_func_support(funcid);
3075 : SupportRequestIndexCondition req;
3076 : List *sresult;
3077 :
3078 16396 : if (!OidIsValid(prosupport))
3079 9442 : return NULL;
3080 :
3081 6954 : req.type = T_SupportRequestIndexCondition;
3082 6954 : req.root = root;
3083 6954 : req.funcid = funcid;
3084 6954 : req.node = (Node *) rinfo->clause;
3085 6954 : req.indexarg = indexarg;
3086 6954 : req.index = index;
3087 6954 : req.indexcol = indexcol;
3088 6954 : req.opfamily = index->opfamily[indexcol];
3089 6954 : req.indexcollation = index->indexcollations[indexcol];
3090 :
3091 6954 : req.lossy = true; /* default assumption */
3092 :
3093 : sresult = (List *)
3094 6954 : DatumGetPointer(OidFunctionCall1(prosupport,
3095 : PointerGetDatum(&req)));
3096 :
3097 6954 : if (sresult != NIL)
3098 : {
3099 1167 : IndexClause *iclause = makeNode(IndexClause);
3100 1167 : List *indexquals = NIL;
3101 : ListCell *lc;
3102 :
3103 : /*
3104 : * The support function API says it should just give back bare
3105 : * clauses, so here we must wrap each one in a RestrictInfo.
3106 : */
3107 3442 : foreach(lc, sresult)
3108 : {
3109 2275 : Expr *clause = (Expr *) lfirst(lc);
3110 :
3111 2275 : indexquals = lappend(indexquals,
3112 2275 : make_simple_restrictinfo(root, clause));
3113 : }
3114 :
3115 1167 : iclause->rinfo = rinfo;
3116 1167 : iclause->indexquals = indexquals;
3117 1167 : iclause->lossy = req.lossy;
3118 1167 : iclause->indexcol = indexcol;
3119 1167 : iclause->indexcols = NIL;
3120 :
3121 1167 : return iclause;
3122 : }
3123 :
3124 5787 : return NULL;
3125 : }
3126 :
3127 : /*
3128 : * match_saopclause_to_indexcol()
3129 : * Handles the ScalarArrayOpExpr case for match_clause_to_indexcol(),
3130 : * which see for comments.
3131 : */
3132 : static IndexClause *
3133 60006 : match_saopclause_to_indexcol(PlannerInfo *root,
3134 : RestrictInfo *rinfo,
3135 : int indexcol,
3136 : IndexOptInfo *index)
3137 : {
3138 60006 : ScalarArrayOpExpr *saop = (ScalarArrayOpExpr *) rinfo->clause;
3139 : Node *leftop,
3140 : *rightop;
3141 : Relids right_relids;
3142 : Oid expr_op;
3143 : Oid expr_coll;
3144 : Index index_relid;
3145 : Oid opfamily;
3146 : Oid idxcollation;
3147 :
3148 : /* We only accept ANY clauses, not ALL */
3149 60006 : if (!saop->useOr)
3150 7465 : return NULL;
3151 52541 : leftop = (Node *) linitial(saop->args);
3152 52541 : rightop = (Node *) lsecond(saop->args);
3153 52541 : right_relids = pull_varnos(root, rightop);
3154 52541 : expr_op = saop->opno;
3155 52541 : expr_coll = saop->inputcollid;
3156 :
3157 52541 : index_relid = index->rel->relid;
3158 52541 : opfamily = index->opfamily[indexcol];
3159 52541 : idxcollation = index->indexcollations[indexcol];
3160 :
3161 : /*
3162 : * We must have indexkey on the left and a pseudo-constant array argument.
3163 : */
3164 52541 : if (match_index_to_operand(leftop, indexcol, index) &&
3165 5445 : !bms_is_member(index_relid, right_relids) &&
3166 5445 : !contain_volatile_functions(rightop))
3167 : {
3168 10885 : if (IndexCollMatchesExprColl(idxcollation, expr_coll) &&
3169 5440 : op_in_opfamily(expr_op, opfamily))
3170 : {
3171 5430 : IndexClause *iclause = makeNode(IndexClause);
3172 :
3173 5430 : iclause->rinfo = rinfo;
3174 5430 : iclause->indexquals = list_make1(rinfo);
3175 5430 : iclause->lossy = false;
3176 5430 : iclause->indexcol = indexcol;
3177 5430 : iclause->indexcols = NIL;
3178 5430 : return iclause;
3179 : }
3180 :
3181 : /*
3182 : * We do not currently ask support functions about ScalarArrayOpExprs,
3183 : * though in principle we could.
3184 : */
3185 : }
3186 :
3187 47111 : return NULL;
3188 : }
3189 :
3190 : /*
3191 : * match_rowcompare_to_indexcol()
3192 : * Handles the RowCompareExpr case for match_clause_to_indexcol(),
3193 : * which see for comments.
3194 : *
3195 : * In this routine we check whether the first column of the row comparison
3196 : * matches the target index column. This is sufficient to guarantee that some
3197 : * index condition can be constructed from the RowCompareExpr --- the rest
3198 : * is handled by expand_indexqual_rowcompare().
3199 : */
3200 : static IndexClause *
3201 420 : match_rowcompare_to_indexcol(PlannerInfo *root,
3202 : RestrictInfo *rinfo,
3203 : int indexcol,
3204 : IndexOptInfo *index)
3205 : {
3206 420 : RowCompareExpr *clause = (RowCompareExpr *) rinfo->clause;
3207 : Index index_relid;
3208 : Oid opfamily;
3209 : Oid idxcollation;
3210 : Node *leftop,
3211 : *rightop;
3212 : bool var_on_left;
3213 : Oid expr_op;
3214 : Oid expr_coll;
3215 :
3216 : /* Forget it if we're not dealing with a btree index */
3217 420 : if (index->relam != BTREE_AM_OID)
3218 0 : return NULL;
3219 :
3220 420 : index_relid = index->rel->relid;
3221 420 : opfamily = index->opfamily[indexcol];
3222 420 : idxcollation = index->indexcollations[indexcol];
3223 :
3224 : /*
3225 : * We could do the matching on the basis of insisting that the opfamily
3226 : * shown in the RowCompareExpr be the same as the index column's opfamily,
3227 : * but that could fail in the presence of reverse-sort opfamilies: it'd be
3228 : * a matter of chance whether RowCompareExpr had picked the forward or
3229 : * reverse-sort family. So look only at the operator, and match if it is
3230 : * a member of the index's opfamily (after commutation, if the indexkey is
3231 : * on the right). We'll worry later about whether any additional
3232 : * operators are matchable to the index.
3233 : */
3234 420 : leftop = (Node *) linitial(clause->largs);
3235 420 : rightop = (Node *) linitial(clause->rargs);
3236 420 : expr_op = linitial_oid(clause->opnos);
3237 420 : expr_coll = linitial_oid(clause->inputcollids);
3238 :
3239 : /* Collations must match, if relevant */
3240 420 : if (!IndexCollMatchesExprColl(idxcollation, expr_coll))
3241 0 : return NULL;
3242 :
3243 : /*
3244 : * These syntactic tests are the same as in match_opclause_to_indexcol()
3245 : */
3246 420 : if (match_index_to_operand(leftop, indexcol, index) &&
3247 135 : !bms_is_member(index_relid, pull_varnos(root, rightop)) &&
3248 135 : !contain_volatile_functions(rightop))
3249 : {
3250 : /* OK, indexkey is on left */
3251 135 : var_on_left = true;
3252 : }
3253 285 : else if (match_index_to_operand(rightop, indexcol, index) &&
3254 20 : !bms_is_member(index_relid, pull_varnos(root, leftop)) &&
3255 20 : !contain_volatile_functions(leftop))
3256 : {
3257 : /* indexkey is on right, so commute the operator */
3258 20 : expr_op = get_commutator(expr_op);
3259 20 : if (expr_op == InvalidOid)
3260 0 : return NULL;
3261 20 : var_on_left = false;
3262 : }
3263 : else
3264 265 : return NULL;
3265 :
3266 : /* We're good if the operator is the right type of opfamily member */
3267 155 : switch (get_op_opfamily_strategy(expr_op, opfamily))
3268 : {
3269 155 : case BTLessStrategyNumber:
3270 : case BTLessEqualStrategyNumber:
3271 : case BTGreaterEqualStrategyNumber:
3272 : case BTGreaterStrategyNumber:
3273 155 : return expand_indexqual_rowcompare(root,
3274 : rinfo,
3275 : indexcol,
3276 : index,
3277 : expr_op,
3278 : var_on_left);
3279 : }
3280 :
3281 0 : return NULL;
3282 : }
3283 :
3284 : /*
3285 : * match_orclause_to_indexcol()
3286 : * Handles the OR-expr case for match_clause_to_indexcol() in the case
3287 : * when it could be transformed to ScalarArrayOpExpr.
3288 : *
3289 : * In this routine, we attempt to transform a list of OR-clause args into a
3290 : * single SAOP expression matching the target index column. On success,
3291 : * return an IndexClause containing the transformed expression.
3292 : * Return NULL if the transformation fails.
3293 : */
3294 : static IndexClause *
3295 40352 : match_orclause_to_indexcol(PlannerInfo *root,
3296 : RestrictInfo *rinfo,
3297 : int indexcol,
3298 : IndexOptInfo *index)
3299 : {
3300 40352 : BoolExpr *orclause = (BoolExpr *) rinfo->orclause;
3301 40352 : List *consts = NIL;
3302 40352 : Node *indexExpr = NULL;
3303 40352 : Oid matchOpno = InvalidOid;
3304 40352 : Oid consttype = InvalidOid;
3305 40352 : Oid arraytype = InvalidOid;
3306 40352 : Oid inputcollid = InvalidOid;
3307 40352 : bool firstTime = true;
3308 40352 : bool haveNonConst = false;
3309 40352 : Index indexRelid = index->rel->relid;
3310 : ScalarArrayOpExpr *saopexpr;
3311 : IndexClause *iclause;
3312 : ListCell *lc;
3313 :
3314 : /* Forget it if index doesn't support SAOP clauses */
3315 40352 : if (!index->amsearcharray)
3316 73 : return NULL;
3317 :
3318 : /*
3319 : * Try to convert a list of OR-clauses to a single SAOP expression. Each
3320 : * OR entry must be in the form: (indexkey operator constant) or (constant
3321 : * operator indexkey). Operators of all the entries must match. On
3322 : * discovery of anything unsupported, we give up by breaking out of the
3323 : * loop immediately and returning NULL.
3324 : */
3325 47811 : foreach(lc, orclause->args)
3326 : {
3327 44948 : RestrictInfo *subRinfo = (RestrictInfo *) lfirst(lc);
3328 : OpExpr *subClause;
3329 : Oid opno;
3330 : Node *leftop,
3331 : *rightop;
3332 : Node *constExpr;
3333 :
3334 : /* If it's not a RestrictInfo (i.e. it's a sub-AND), we can't use it */
3335 44948 : if (!IsA(subRinfo, RestrictInfo))
3336 3433 : break;
3337 :
3338 : /* Only operator clauses can match */
3339 41515 : if (!IsA(subRinfo->clause, OpExpr))
3340 11966 : break;
3341 :
3342 29549 : subClause = (OpExpr *) subRinfo->clause;
3343 29549 : opno = subClause->opno;
3344 :
3345 : /* Only binary operators can match */
3346 29549 : if (list_length(subClause->args) != 2)
3347 0 : break;
3348 :
3349 : /*
3350 : * Check for clauses of the form: (indexkey operator constant) or
3351 : * (constant operator indexkey). These tests should agree with
3352 : * match_opclause_to_indexcol.
3353 : */
3354 29549 : leftop = (Node *) linitial(subClause->args);
3355 29549 : rightop = (Node *) lsecond(subClause->args);
3356 29549 : if (match_index_to_operand(leftop, indexcol, index) &&
3357 8855 : !bms_is_member(indexRelid, subRinfo->right_relids) &&
3358 8830 : !contain_volatile_functions(rightop))
3359 : {
3360 8830 : indexExpr = leftop;
3361 8830 : constExpr = rightop;
3362 : }
3363 20719 : else if (match_index_to_operand(rightop, indexcol, index) &&
3364 147 : !bms_is_member(indexRelid, subRinfo->left_relids) &&
3365 142 : !contain_volatile_functions(leftop))
3366 : {
3367 142 : opno = get_commutator(opno);
3368 142 : if (!OidIsValid(opno))
3369 : {
3370 : /* commutator doesn't exist, we can't reverse the order */
3371 0 : break;
3372 : }
3373 142 : indexExpr = rightop;
3374 142 : constExpr = leftop;
3375 : }
3376 : else
3377 : {
3378 : break;
3379 : }
3380 :
3381 : /*
3382 : * Save information about the operator, type, and collation for the
3383 : * first matching qual. Then, check that subsequent quals match the
3384 : * first.
3385 : */
3386 8972 : if (firstTime)
3387 : {
3388 5519 : matchOpno = opno;
3389 5519 : consttype = exprType(constExpr);
3390 5519 : arraytype = get_array_type(consttype);
3391 5519 : inputcollid = subClause->inputcollid;
3392 :
3393 : /*
3394 : * Check that the operator is presented in the opfamily and that
3395 : * the expression collation matches the index collation. Also,
3396 : * there must be an array type to construct an array later.
3397 : */
3398 5519 : if (!IndexCollMatchesExprColl(index->indexcollations[indexcol],
3399 5414 : inputcollid) ||
3400 5414 : !op_in_opfamily(matchOpno, index->opfamily[indexcol]) ||
3401 : !OidIsValid(arraytype))
3402 : break;
3403 :
3404 : /*
3405 : * Disallow if either type is RECORD, mainly because we can't be
3406 : * positive that all the RHS expressions are the same record type.
3407 : */
3408 4199 : if (consttype == RECORDOID || exprType(indexExpr) == RECORDOID)
3409 : break;
3410 :
3411 4199 : firstTime = false;
3412 : }
3413 : else
3414 : {
3415 3453 : if (matchOpno != opno ||
3416 6666 : inputcollid != subClause->inputcollid ||
3417 3333 : consttype != exprType(constExpr))
3418 : break;
3419 : }
3420 :
3421 : /*
3422 : * The righthand inputs don't necessarily have to be plain Consts, but
3423 : * make_SAOP_expr needs to know if any are not.
3424 : */
3425 7532 : if (!IsA(constExpr, Const))
3426 312 : haveNonConst = true;
3427 :
3428 7532 : consts = lappend(consts, constExpr);
3429 : }
3430 :
3431 : /*
3432 : * Handle failed conversion from breaking out of the loop because of an
3433 : * unsupported qual. Also check that we have an indexExpr, just in case
3434 : * the OR list was somehow empty (it shouldn't be). Return NULL to
3435 : * indicate the conversion failed.
3436 : */
3437 40279 : if (lc != NULL || indexExpr == NULL)
3438 : {
3439 37416 : list_free(consts); /* might as well */
3440 37416 : return NULL;
3441 : }
3442 :
3443 : /*
3444 : * Build the new SAOP node. We use the indexExpr from the last OR arm;
3445 : * since all the arms passed match_index_to_operand, it shouldn't matter
3446 : * which one we use. But using "inputcollid" twice is a bit of a cheat:
3447 : * we might end up with an array Const node that is labeled with a
3448 : * collation despite its elements being of a noncollatable type. But
3449 : * nothing is likely to complain about that, so we don't bother being more
3450 : * accurate.
3451 : */
3452 2863 : saopexpr = make_SAOP_expr(matchOpno, indexExpr, consttype, inputcollid,
3453 : inputcollid, consts, haveNonConst);
3454 : Assert(saopexpr != NULL);
3455 :
3456 : /*
3457 : * Finally, build an IndexClause based on the SAOP node. It's not lossy.
3458 : */
3459 2863 : iclause = makeNode(IndexClause);
3460 2863 : iclause->rinfo = rinfo;
3461 2863 : iclause->indexquals = list_make1(make_simple_restrictinfo(root,
3462 : (Expr *) saopexpr));
3463 2863 : iclause->lossy = false;
3464 2863 : iclause->indexcol = indexcol;
3465 2863 : iclause->indexcols = NIL;
3466 2863 : return iclause;
3467 : }
3468 :
3469 : /*
3470 : * expand_indexqual_rowcompare --- expand a single indexqual condition
3471 : * that is a RowCompareExpr
3472 : *
3473 : * It's already known that the first column of the row comparison matches
3474 : * the specified column of the index. We can use additional columns of the
3475 : * row comparison as index qualifications, so long as they match the index
3476 : * in the "same direction", ie, the indexkeys are all on the same side of the
3477 : * clause and the operators are all the same-type members of the opfamilies.
3478 : *
3479 : * If all the columns of the RowCompareExpr match in this way, we just use it
3480 : * as-is, except for possibly commuting it to put the indexkeys on the left.
3481 : *
3482 : * Otherwise, we build a shortened RowCompareExpr (if more than one
3483 : * column matches) or a simple OpExpr (if the first-column match is all
3484 : * there is). In these cases the modified clause is always "<=" or ">="
3485 : * even when the original was "<" or ">" --- this is necessary to match all
3486 : * the rows that could match the original. (We are building a lossy version
3487 : * of the row comparison when we do this, so we set lossy = true.)
3488 : *
3489 : * Note: this is really just the last half of match_rowcompare_to_indexcol,
3490 : * but we split it out for comprehensibility.
3491 : */
3492 : static IndexClause *
3493 155 : expand_indexqual_rowcompare(PlannerInfo *root,
3494 : RestrictInfo *rinfo,
3495 : int indexcol,
3496 : IndexOptInfo *index,
3497 : Oid expr_op,
3498 : bool var_on_left)
3499 : {
3500 155 : IndexClause *iclause = makeNode(IndexClause);
3501 155 : RowCompareExpr *clause = (RowCompareExpr *) rinfo->clause;
3502 : int op_strategy;
3503 : Oid op_lefttype;
3504 : Oid op_righttype;
3505 : int matching_cols;
3506 : List *expr_ops;
3507 : List *opfamilies;
3508 : List *lefttypes;
3509 : List *righttypes;
3510 : List *new_ops;
3511 : List *var_args;
3512 : List *non_var_args;
3513 :
3514 155 : iclause->rinfo = rinfo;
3515 155 : iclause->indexcol = indexcol;
3516 :
3517 155 : if (var_on_left)
3518 : {
3519 135 : var_args = clause->largs;
3520 135 : non_var_args = clause->rargs;
3521 : }
3522 : else
3523 : {
3524 20 : var_args = clause->rargs;
3525 20 : non_var_args = clause->largs;
3526 : }
3527 :
3528 155 : get_op_opfamily_properties(expr_op, index->opfamily[indexcol], false,
3529 : &op_strategy,
3530 : &op_lefttype,
3531 : &op_righttype);
3532 :
3533 : /* Initialize returned list of which index columns are used */
3534 155 : iclause->indexcols = list_make1_int(indexcol);
3535 :
3536 : /* Build lists of ops, opfamilies and operator datatypes in case needed */
3537 155 : expr_ops = list_make1_oid(expr_op);
3538 155 : opfamilies = list_make1_oid(index->opfamily[indexcol]);
3539 155 : lefttypes = list_make1_oid(op_lefttype);
3540 155 : righttypes = list_make1_oid(op_righttype);
3541 :
3542 : /*
3543 : * See how many of the remaining columns match some index column in the
3544 : * same way. As in match_clause_to_indexcol(), the "other" side of any
3545 : * potential index condition is OK as long as it doesn't use Vars from the
3546 : * indexed relation.
3547 : */
3548 155 : matching_cols = 1;
3549 :
3550 295 : while (matching_cols < list_length(var_args))
3551 : {
3552 185 : Node *varop = (Node *) list_nth(var_args, matching_cols);
3553 185 : Node *constop = (Node *) list_nth(non_var_args, matching_cols);
3554 : int i;
3555 :
3556 185 : expr_op = list_nth_oid(clause->opnos, matching_cols);
3557 185 : if (!var_on_left)
3558 : {
3559 : /* indexkey is on right, so commute the operator */
3560 20 : expr_op = get_commutator(expr_op);
3561 20 : if (expr_op == InvalidOid)
3562 0 : break; /* operator is not usable */
3563 : }
3564 185 : if (bms_is_member(index->rel->relid, pull_varnos(root, constop)))
3565 0 : break; /* no good, Var on wrong side */
3566 185 : if (contain_volatile_functions(constop))
3567 0 : break; /* no good, volatile comparison value */
3568 :
3569 : /*
3570 : * The Var side can match any key column of the index.
3571 : */
3572 430 : for (i = 0; i < index->nkeycolumns; i++)
3573 : {
3574 385 : if (match_index_to_operand(varop, i, index) &&
3575 140 : get_op_opfamily_strategy(expr_op,
3576 140 : index->opfamily[i]) == op_strategy &&
3577 140 : IndexCollMatchesExprColl(index->indexcollations[i],
3578 : list_nth_oid(clause->inputcollids,
3579 : matching_cols)))
3580 : break;
3581 : }
3582 185 : if (i >= index->nkeycolumns)
3583 45 : break; /* no match found */
3584 :
3585 : /* Add column number to returned list */
3586 140 : iclause->indexcols = lappend_int(iclause->indexcols, i);
3587 :
3588 : /* Add operator info to lists */
3589 140 : get_op_opfamily_properties(expr_op, index->opfamily[i], false,
3590 : &op_strategy,
3591 : &op_lefttype,
3592 : &op_righttype);
3593 140 : expr_ops = lappend_oid(expr_ops, expr_op);
3594 140 : opfamilies = lappend_oid(opfamilies, index->opfamily[i]);
3595 140 : lefttypes = lappend_oid(lefttypes, op_lefttype);
3596 140 : righttypes = lappend_oid(righttypes, op_righttype);
3597 :
3598 : /* This column matches, keep scanning */
3599 140 : matching_cols++;
3600 : }
3601 :
3602 : /* Result is non-lossy if all columns are usable as index quals */
3603 155 : iclause->lossy = (matching_cols != list_length(clause->opnos));
3604 :
3605 : /*
3606 : * We can use rinfo->clause as-is if we have var on left and it's all
3607 : * usable as index quals.
3608 : */
3609 155 : if (var_on_left && !iclause->lossy)
3610 100 : iclause->indexquals = list_make1(rinfo);
3611 : else
3612 : {
3613 : /*
3614 : * We have to generate a modified rowcompare (possibly just one
3615 : * OpExpr). The painful part of this is changing < to <= or > to >=,
3616 : * so deal with that first.
3617 : */
3618 55 : if (!iclause->lossy)
3619 : {
3620 : /* very easy, just use the commuted operators */
3621 10 : new_ops = expr_ops;
3622 : }
3623 45 : else if (op_strategy == BTLessEqualStrategyNumber ||
3624 45 : op_strategy == BTGreaterEqualStrategyNumber)
3625 : {
3626 : /* easy, just use the same (possibly commuted) operators */
3627 0 : new_ops = list_truncate(expr_ops, matching_cols);
3628 : }
3629 : else
3630 : {
3631 : ListCell *opfamilies_cell;
3632 : ListCell *lefttypes_cell;
3633 : ListCell *righttypes_cell;
3634 :
3635 45 : if (op_strategy == BTLessStrategyNumber)
3636 25 : op_strategy = BTLessEqualStrategyNumber;
3637 20 : else if (op_strategy == BTGreaterStrategyNumber)
3638 20 : op_strategy = BTGreaterEqualStrategyNumber;
3639 : else
3640 0 : elog(ERROR, "unexpected strategy number %d", op_strategy);
3641 45 : new_ops = NIL;
3642 120 : forthree(opfamilies_cell, opfamilies,
3643 : lefttypes_cell, lefttypes,
3644 : righttypes_cell, righttypes)
3645 : {
3646 75 : Oid opfam = lfirst_oid(opfamilies_cell);
3647 75 : Oid lefttype = lfirst_oid(lefttypes_cell);
3648 75 : Oid righttype = lfirst_oid(righttypes_cell);
3649 :
3650 75 : expr_op = get_opfamily_member(opfam, lefttype, righttype,
3651 : op_strategy);
3652 75 : if (!OidIsValid(expr_op)) /* should not happen */
3653 0 : elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
3654 : op_strategy, lefttype, righttype, opfam);
3655 75 : new_ops = lappend_oid(new_ops, expr_op);
3656 : }
3657 : }
3658 :
3659 : /* If we have more than one matching col, create a subset rowcompare */
3660 55 : if (matching_cols > 1)
3661 : {
3662 40 : RowCompareExpr *rc = makeNode(RowCompareExpr);
3663 :
3664 40 : rc->cmptype = (CompareType) op_strategy;
3665 40 : rc->opnos = new_ops;
3666 40 : rc->opfamilies = list_copy_head(clause->opfamilies,
3667 : matching_cols);
3668 40 : rc->inputcollids = list_copy_head(clause->inputcollids,
3669 : matching_cols);
3670 40 : rc->largs = list_copy_head(var_args, matching_cols);
3671 40 : rc->rargs = list_copy_head(non_var_args, matching_cols);
3672 40 : iclause->indexquals = list_make1(make_simple_restrictinfo(root,
3673 : (Expr *) rc));
3674 : }
3675 : else
3676 : {
3677 : Expr *op;
3678 :
3679 : /* We don't report an index column list in this case */
3680 15 : iclause->indexcols = NIL;
3681 :
3682 15 : op = make_opclause(linitial_oid(new_ops), BOOLOID, false,
3683 15 : copyObject(linitial(var_args)),
3684 15 : copyObject(linitial(non_var_args)),
3685 : InvalidOid,
3686 15 : linitial_oid(clause->inputcollids));
3687 15 : iclause->indexquals = list_make1(make_simple_restrictinfo(root, op));
3688 : }
3689 : }
3690 :
3691 155 : return iclause;
3692 : }
3693 :
3694 :
3695 : /****************************************************************************
3696 : * ---- ROUTINES TO CHECK ORDERING OPERATORS ----
3697 : ****************************************************************************/
3698 :
3699 : /*
3700 : * match_pathkeys_to_index
3701 : * For the given 'index' and 'pathkeys', output a list of suitable ORDER
3702 : * BY expressions, each of the form "indexedcol operator pseudoconstant",
3703 : * along with an integer list of the index column numbers (zero based)
3704 : * that each clause would be used with.
3705 : *
3706 : * This attempts to find an ORDER BY and index column number for all items in
3707 : * the pathkey list, however, if we're unable to match any given pathkey to an
3708 : * index column, we return just the ones matched by the function so far. This
3709 : * allows callers who are interested in partial matches to get them. Callers
3710 : * can determine a partial match vs a full match by checking the outputted
3711 : * list lengths. A full match will have one item in the output lists for each
3712 : * item in the given 'pathkeys' list.
3713 : */
3714 : static void
3715 1340 : match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys,
3716 : List **orderby_clauses_p,
3717 : List **clause_columns_p)
3718 : {
3719 : ListCell *lc1;
3720 :
3721 1340 : *orderby_clauses_p = NIL; /* set default results */
3722 1340 : *clause_columns_p = NIL;
3723 :
3724 : /* Only indexes with the amcanorderbyop property are interesting here */
3725 1340 : if (!index->amcanorderbyop)
3726 0 : return;
3727 :
3728 1699 : foreach(lc1, pathkeys)
3729 : {
3730 1320 : PathKey *pathkey = (PathKey *) lfirst(lc1);
3731 1320 : bool found = false;
3732 : EquivalenceMemberIterator it;
3733 : EquivalenceMember *member;
3734 :
3735 :
3736 : /* Pathkey must request default sort order for the target opfamily */
3737 1320 : if (pathkey->pk_cmptype != COMPARE_LT || pathkey->pk_nulls_first)
3738 961 : return;
3739 :
3740 : /* If eclass is volatile, no hope of using an indexscan */
3741 1301 : if (pathkey->pk_eclass->ec_has_volatile)
3742 0 : return;
3743 :
3744 : /*
3745 : * Try to match eclass member expression(s) to index. Note that child
3746 : * EC members are considered, but only when they belong to the target
3747 : * relation. (Unlike regular members, the same expression could be a
3748 : * child member of more than one EC. Therefore, the same index could
3749 : * be considered to match more than one pathkey list, which is OK
3750 : * here. See also get_eclass_for_sort_expr.)
3751 : */
3752 1301 : setup_eclass_member_iterator(&it, pathkey->pk_eclass,
3753 1301 : index->rel->relids);
3754 2302 : while ((member = eclass_member_iterator_next(&it)) != NULL)
3755 : {
3756 : int indexcol;
3757 :
3758 : /* No possibility of match if it references other relations */
3759 1360 : if (!bms_equal(member->em_relids, index->rel->relids))
3760 59 : continue;
3761 :
3762 : /*
3763 : * We allow any column of the index to match each pathkey; they
3764 : * don't have to match left-to-right as you might expect. This is
3765 : * correct for GiST, and it doesn't matter for SP-GiST because
3766 : * that doesn't handle multiple columns anyway, and no other
3767 : * existing AMs support amcanorderbyop. We might need different
3768 : * logic in future for other implementations.
3769 : */
3770 2967 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
3771 : {
3772 : Expr *expr;
3773 :
3774 2025 : expr = match_clause_to_ordering_op(index,
3775 : indexcol,
3776 : member->em_expr,
3777 : pathkey->pk_opfamily);
3778 2025 : if (expr)
3779 : {
3780 359 : *orderby_clauses_p = lappend(*orderby_clauses_p, expr);
3781 359 : *clause_columns_p = lappend_int(*clause_columns_p, indexcol);
3782 359 : found = true;
3783 359 : break;
3784 : }
3785 : }
3786 :
3787 1301 : if (found) /* don't want to look at remaining members */
3788 359 : break;
3789 : }
3790 :
3791 : /*
3792 : * Return the matches found so far when this pathkey couldn't be
3793 : * matched to the index.
3794 : */
3795 1301 : if (!found)
3796 942 : return;
3797 : }
3798 : }
3799 :
3800 : /*
3801 : * match_clause_to_ordering_op
3802 : * Determines whether an ordering operator expression matches an
3803 : * index column.
3804 : *
3805 : * This is similar to, but simpler than, match_clause_to_indexcol.
3806 : * We only care about simple OpExpr cases. The input is a bare
3807 : * expression that is being ordered by, which must be of the form
3808 : * (indexkey op const) or (const op indexkey) where op is an ordering
3809 : * operator for the column's opfamily.
3810 : *
3811 : * 'index' is the index of interest.
3812 : * 'indexcol' is a column number of 'index' (counting from 0).
3813 : * 'clause' is the ordering expression to be tested.
3814 : * 'pk_opfamily' is the btree opfamily describing the required sort order.
3815 : *
3816 : * Note that we currently do not consider the collation of the ordering
3817 : * operator's result. In practical cases the result type will be numeric
3818 : * and thus have no collation, and it's not very clear what to match to
3819 : * if it did have a collation. The index's collation should match the
3820 : * ordering operator's input collation, not its result.
3821 : *
3822 : * If successful, return 'clause' as-is if the indexkey is on the left,
3823 : * otherwise a commuted copy of 'clause'. If no match, return NULL.
3824 : */
3825 : static Expr *
3826 2025 : match_clause_to_ordering_op(IndexOptInfo *index,
3827 : int indexcol,
3828 : Expr *clause,
3829 : Oid pk_opfamily)
3830 : {
3831 : Oid opfamily;
3832 : Oid idxcollation;
3833 : Node *leftop,
3834 : *rightop;
3835 : Oid expr_op;
3836 : Oid expr_coll;
3837 : Oid sortfamily;
3838 : bool commuted;
3839 :
3840 : Assert(indexcol < index->nkeycolumns);
3841 :
3842 2025 : opfamily = index->opfamily[indexcol];
3843 2025 : idxcollation = index->indexcollations[indexcol];
3844 :
3845 : /*
3846 : * Clause must be a binary opclause.
3847 : */
3848 2025 : if (!is_opclause(clause))
3849 1666 : return NULL;
3850 359 : leftop = get_leftop(clause);
3851 359 : rightop = get_rightop(clause);
3852 359 : if (!leftop || !rightop)
3853 0 : return NULL;
3854 359 : expr_op = ((OpExpr *) clause)->opno;
3855 359 : expr_coll = ((OpExpr *) clause)->inputcollid;
3856 :
3857 : /*
3858 : * We can forget the whole thing right away if wrong collation.
3859 : */
3860 359 : if (!IndexCollMatchesExprColl(idxcollation, expr_coll))
3861 0 : return NULL;
3862 :
3863 : /*
3864 : * Check for clauses of the form: (indexkey operator constant) or
3865 : * (constant operator indexkey).
3866 : */
3867 359 : if (match_index_to_operand(leftop, indexcol, index) &&
3868 339 : !contain_var_clause(rightop) &&
3869 339 : !contain_volatile_functions(rightop))
3870 : {
3871 339 : commuted = false;
3872 : }
3873 20 : else if (match_index_to_operand(rightop, indexcol, index) &&
3874 20 : !contain_var_clause(leftop) &&
3875 20 : !contain_volatile_functions(leftop))
3876 : {
3877 : /* Might match, but we need a commuted operator */
3878 20 : expr_op = get_commutator(expr_op);
3879 20 : if (expr_op == InvalidOid)
3880 0 : return NULL;
3881 20 : commuted = true;
3882 : }
3883 : else
3884 0 : return NULL;
3885 :
3886 : /*
3887 : * Is the (commuted) operator an ordering operator for the opfamily? And
3888 : * if so, does it yield the right sorting semantics?
3889 : */
3890 359 : sortfamily = get_op_opfamily_sortfamily(expr_op, opfamily);
3891 359 : if (sortfamily != pk_opfamily)
3892 0 : return NULL;
3893 :
3894 : /* We have a match. Return clause or a commuted version thereof. */
3895 359 : if (commuted)
3896 : {
3897 20 : OpExpr *newclause = makeNode(OpExpr);
3898 :
3899 : /* flat-copy all the fields of clause */
3900 20 : memcpy(newclause, clause, sizeof(OpExpr));
3901 :
3902 : /* commute it */
3903 20 : newclause->opno = expr_op;
3904 20 : newclause->opfuncid = InvalidOid;
3905 20 : newclause->args = list_make2(rightop, leftop);
3906 :
3907 20 : clause = (Expr *) newclause;
3908 : }
3909 :
3910 359 : return clause;
3911 : }
3912 :
3913 :
3914 : /****************************************************************************
3915 : * ---- ROUTINES TO DO PARTIAL INDEX PREDICATE TESTS ----
3916 : ****************************************************************************/
3917 :
3918 : /*
3919 : * check_index_predicates
3920 : * Set the predicate-derived IndexOptInfo fields for each index
3921 : * of the specified relation.
3922 : *
3923 : * predOK is set true if the index is partial and its predicate is satisfied
3924 : * for this query, ie the query's WHERE clauses imply the predicate.
3925 : *
3926 : * indrestrictinfo is set to the relation's baserestrictinfo list less any
3927 : * conditions that are implied by the index's predicate. (Obviously, for a
3928 : * non-partial index, this is the same as baserestrictinfo.) Such conditions
3929 : * can be dropped from the plan when using the index, in certain cases.
3930 : *
3931 : * At one time it was possible for this to get re-run after adding more
3932 : * restrictions to the rel, thus possibly letting us prove more indexes OK.
3933 : * That doesn't happen any more (at least not in the core code's usage),
3934 : * but this code still supports it in case extensions want to mess with the
3935 : * baserestrictinfo list. We assume that adding more restrictions can't make
3936 : * an index not predOK. We must recompute indrestrictinfo each time, though,
3937 : * to make sure any newly-added restrictions get into it if needed.
3938 : */
3939 : void
3940 322058 : check_index_predicates(PlannerInfo *root, RelOptInfo *rel)
3941 : {
3942 : List *clauselist;
3943 : bool have_partial;
3944 : bool is_target_rel;
3945 : Relids otherrels;
3946 : ListCell *lc;
3947 :
3948 : /* Indexes are available only on base or "other" member relations. */
3949 : Assert(IS_SIMPLE_REL(rel));
3950 :
3951 : /*
3952 : * Initialize the indrestrictinfo lists to be identical to
3953 : * baserestrictinfo, and check whether there are any partial indexes. If
3954 : * not, this is all we need to do.
3955 : */
3956 322058 : have_partial = false;
3957 884927 : foreach(lc, rel->indexlist)
3958 : {
3959 562869 : IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
3960 :
3961 562869 : index->indrestrictinfo = rel->baserestrictinfo;
3962 562869 : if (index->indpred)
3963 825 : have_partial = true;
3964 : }
3965 322058 : if (!have_partial)
3966 321513 : return;
3967 :
3968 : /*
3969 : * Construct a list of clauses that we can assume true for the purpose of
3970 : * proving the index(es) usable. Restriction clauses for the rel are
3971 : * always usable, and so are any join clauses that are "movable to" this
3972 : * rel. Also, we can consider any EC-derivable join clauses (which must
3973 : * be "movable to" this rel, by definition).
3974 : */
3975 545 : clauselist = list_copy(rel->baserestrictinfo);
3976 :
3977 : /* Scan the rel's join clauses */
3978 545 : foreach(lc, rel->joininfo)
3979 : {
3980 0 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
3981 :
3982 : /* Check if clause can be moved to this rel */
3983 0 : if (!join_clause_is_movable_to(rinfo, rel))
3984 0 : continue;
3985 :
3986 0 : clauselist = lappend(clauselist, rinfo);
3987 : }
3988 :
3989 : /*
3990 : * Add on any equivalence-derivable join clauses. Computing the correct
3991 : * relid sets for generate_join_implied_equalities is slightly tricky
3992 : * because the rel could be a child rel rather than a true baserel, and in
3993 : * that case we must subtract its parents' relid(s) from all_query_rels.
3994 : * Additionally, we mustn't consider clauses that are only computable
3995 : * after outer joins that can null the rel.
3996 : */
3997 545 : if (rel->reloptkind == RELOPT_OTHER_MEMBER_REL)
3998 60 : otherrels = bms_difference(root->all_query_rels,
3999 60 : find_childrel_parents(root, rel));
4000 : else
4001 485 : otherrels = bms_difference(root->all_query_rels, rel->relids);
4002 545 : otherrels = bms_del_members(otherrels, rel->nulling_relids);
4003 :
4004 545 : if (!bms_is_empty(otherrels))
4005 : clauselist =
4006 76 : list_concat(clauselist,
4007 76 : generate_join_implied_equalities(root,
4008 76 : bms_union(rel->relids,
4009 : otherrels),
4010 : otherrels,
4011 : rel,
4012 : NULL));
4013 :
4014 : /*
4015 : * Normally we remove quals that are implied by a partial index's
4016 : * predicate from indrestrictinfo, indicating that they need not be
4017 : * checked explicitly by an indexscan plan using this index. However, if
4018 : * the rel is a target relation of UPDATE/DELETE/MERGE/SELECT FOR UPDATE,
4019 : * we cannot remove such quals from the plan, because they need to be in
4020 : * the plan so that they will be properly rechecked by EvalPlanQual
4021 : * testing. Some day we might want to remove such quals from the main
4022 : * plan anyway and pass them through to EvalPlanQual via a side channel;
4023 : * but for now, we just don't remove implied quals at all for target
4024 : * relations.
4025 : */
4026 1008 : is_target_rel = (bms_is_member(rel->relid, root->all_result_relids) ||
4027 463 : get_plan_rowmark(root->rowMarks, rel->relid) != NULL);
4028 :
4029 : /*
4030 : * Now try to prove each index predicate true, and compute the
4031 : * indrestrictinfo lists for partial indexes. Note that we compute the
4032 : * indrestrictinfo list even for non-predOK indexes; this might seem
4033 : * wasteful, but we may be able to use such indexes in OR clauses, cf
4034 : * generate_bitmap_or_paths().
4035 : */
4036 1736 : foreach(lc, rel->indexlist)
4037 : {
4038 1191 : IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
4039 : ListCell *lcr;
4040 :
4041 1191 : if (index->indpred == NIL)
4042 366 : continue; /* ignore non-partial indexes here */
4043 :
4044 825 : if (!index->predOK) /* don't repeat work if already proven OK */
4045 825 : index->predOK = predicate_implied_by(index->indpred, clauselist,
4046 : false);
4047 :
4048 : /* If rel is an update target, leave indrestrictinfo as set above */
4049 825 : if (is_target_rel)
4050 132 : continue;
4051 :
4052 : /*
4053 : * If index is !amoptionalkey, also leave indrestrictinfo as set
4054 : * above. Otherwise we risk removing all quals for the first index
4055 : * key and then not being able to generate an indexscan at all. It
4056 : * would be better to be more selective, but we've not yet identified
4057 : * which if any of the quals match the first index key.
4058 : */
4059 693 : if (!index->amoptionalkey)
4060 30 : continue;
4061 :
4062 : /* Else compute indrestrictinfo as the non-implied quals */
4063 663 : index->indrestrictinfo = NIL;
4064 1569 : foreach(lcr, rel->baserestrictinfo)
4065 : {
4066 906 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lcr);
4067 :
4068 : /* predicate_implied_by() assumes first arg is immutable */
4069 906 : if (contain_mutable_functions((Node *) rinfo->clause) ||
4070 906 : !predicate_implied_by(list_make1(rinfo->clause),
4071 : index->indpred, false))
4072 661 : index->indrestrictinfo = lappend(index->indrestrictinfo, rinfo);
4073 : }
4074 : }
4075 : }
4076 :
4077 : /****************************************************************************
4078 : * ---- ROUTINES TO CHECK EXTERNALLY-VISIBLE CONDITIONS ----
4079 : ****************************************************************************/
4080 :
4081 : /*
4082 : * ec_member_matches_indexcol
4083 : * Test whether an EquivalenceClass member matches an index column.
4084 : *
4085 : * This is a callback for use by generate_implied_equalities_for_column.
4086 : */
4087 : static bool
4088 385579 : ec_member_matches_indexcol(PlannerInfo *root, RelOptInfo *rel,
4089 : EquivalenceClass *ec, EquivalenceMember *em,
4090 : void *arg)
4091 : {
4092 385579 : IndexOptInfo *index = ((ec_member_matches_arg *) arg)->index;
4093 385579 : int indexcol = ((ec_member_matches_arg *) arg)->indexcol;
4094 : Oid curFamily;
4095 : Oid curCollation;
4096 :
4097 : Assert(indexcol < index->nkeycolumns);
4098 :
4099 385579 : curFamily = index->opfamily[indexcol];
4100 385579 : curCollation = index->indexcollations[indexcol];
4101 :
4102 : /*
4103 : * If it's a btree index, we can reject it if its opfamily isn't
4104 : * compatible with the EC, since no clause generated from the EC could be
4105 : * used with the index. For non-btree indexes, we can't easily tell
4106 : * whether clauses generated from the EC could be used with the index, so
4107 : * don't check the opfamily. This might mean we return "true" for a
4108 : * useless EC, so we have to recheck the results of
4109 : * generate_implied_equalities_for_column; see
4110 : * match_eclass_clauses_to_index.
4111 : */
4112 385579 : if (index->relam == BTREE_AM_OID &&
4113 385524 : !list_member_oid(ec->ec_opfamilies, curFamily))
4114 121045 : return false;
4115 :
4116 : /* We insist on collation match for all index types, though */
4117 264534 : if (!IndexCollMatchesExprColl(curCollation, ec->ec_collation))
4118 9 : return false;
4119 :
4120 264525 : return match_index_to_operand((Node *) em->em_expr, indexcol, index);
4121 : }
4122 :
4123 : /*
4124 : * relation_has_unique_index_for
4125 : * Determine whether the relation provably has at most one row satisfying
4126 : * a set of equality conditions, because the conditions constrain all
4127 : * columns of some unique index.
4128 : *
4129 : * The conditions are provided as a list of RestrictInfo nodes, where the
4130 : * caller has already determined that each condition is a mergejoinable
4131 : * equality with an expression in this relation on one side, and an
4132 : * expression not involving this relation on the other. The transient
4133 : * outer_is_left flag is used to identify which side we should look at:
4134 : * left side if outer_is_left is false, right side if it is true.
4135 : *
4136 : * The caller need only supply equality conditions arising from joins;
4137 : * this routine automatically adds in any usable baserestrictinfo clauses.
4138 : * (Note that the passed-in restrictlist will be destructively modified!)
4139 : *
4140 : * If extra_clauses isn't NULL, return baserestrictinfo clauses which were used
4141 : * to derive uniqueness.
4142 : */
4143 : bool
4144 181965 : relation_has_unique_index_for(PlannerInfo *root, RelOptInfo *rel,
4145 : List *restrictlist, List **extra_clauses)
4146 : {
4147 : ListCell *ic;
4148 :
4149 : /* Short-circuit if no indexes... */
4150 181965 : if (rel->indexlist == NIL)
4151 0 : return false;
4152 :
4153 : /*
4154 : * Examine the rel's restriction clauses for usable var = const clauses
4155 : * that we can add to the restrictlist.
4156 : */
4157 308286 : foreach(ic, rel->baserestrictinfo)
4158 : {
4159 126321 : RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(ic);
4160 :
4161 : /*
4162 : * Note: can_join won't be set for a restriction clause, but
4163 : * mergeopfamilies will be if it has a mergejoinable operator and
4164 : * doesn't contain volatile functions.
4165 : */
4166 126321 : if (restrictinfo->mergeopfamilies == NIL)
4167 54133 : continue; /* not mergejoinable */
4168 :
4169 : /*
4170 : * The clause certainly doesn't refer to anything but the given rel.
4171 : * If either side is pseudoconstant then we can use it.
4172 : */
4173 72188 : if (bms_is_empty(restrictinfo->left_relids))
4174 : {
4175 : /* righthand side is inner */
4176 37 : restrictinfo->outer_is_left = true;
4177 : }
4178 72151 : else if (bms_is_empty(restrictinfo->right_relids))
4179 : {
4180 : /* lefthand side is inner */
4181 72046 : restrictinfo->outer_is_left = false;
4182 : }
4183 : else
4184 105 : continue;
4185 :
4186 : /* OK, add to list */
4187 72083 : restrictlist = lappend(restrictlist, restrictinfo);
4188 : }
4189 :
4190 : /* Short-circuit the easy case */
4191 181965 : if (restrictlist == NIL)
4192 984 : return false;
4193 :
4194 : /* Examine each index of the relation ... */
4195 459311 : foreach(ic, rel->indexlist)
4196 : {
4197 385391 : IndexOptInfo *ind = (IndexOptInfo *) lfirst(ic);
4198 : int c;
4199 385391 : List *exprs = NIL;
4200 :
4201 : /*
4202 : * If the index is not unique, or not immediately enforced, or if it's
4203 : * a partial index, it's useless here. We're unable to make use of
4204 : * predOK partial unique indexes due to the fact that
4205 : * check_index_predicates() also makes use of join predicates to
4206 : * determine if the partial index is usable. Here we need proofs that
4207 : * hold true before any joins are evaluated.
4208 : */
4209 385391 : if (!ind->unique || !ind->immediate || ind->indpred != NIL)
4210 106801 : continue;
4211 :
4212 : /*
4213 : * Try to find each index column in the list of conditions. This is
4214 : * O(N^2) or worse, but we expect all the lists to be short.
4215 : */
4216 468613 : for (c = 0; c < ind->nkeycolumns; c++)
4217 : {
4218 : ListCell *lc;
4219 :
4220 693702 : foreach(lc, restrictlist)
4221 : {
4222 522173 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
4223 : Node *rexpr;
4224 :
4225 : /*
4226 : * The condition's equality operator must be a member of the
4227 : * index opfamily, else it is not asserting the right kind of
4228 : * equality behavior for this index. We check this first
4229 : * since it's probably cheaper than match_index_to_operand().
4230 : */
4231 522173 : if (!list_member_oid(rinfo->mergeopfamilies, ind->opfamily[c]))
4232 162133 : continue;
4233 :
4234 : /*
4235 : * XXX at some point we may need to check collations here too.
4236 : * For the moment we assume all collations reduce to the same
4237 : * notion of equality.
4238 : */
4239 :
4240 : /* OK, see if the condition operand matches the index key */
4241 360040 : if (rinfo->outer_is_left)
4242 140697 : rexpr = get_rightop(rinfo->clause);
4243 : else
4244 219343 : rexpr = get_leftop(rinfo->clause);
4245 :
4246 360040 : if (match_index_to_operand(rexpr, c, ind))
4247 : {
4248 190023 : if (bms_membership(rinfo->clause_relids) == BMS_SINGLETON)
4249 : {
4250 : MemoryContext oldMemCtx =
4251 46217 : MemoryContextSwitchTo(root->planner_cxt);
4252 :
4253 : /*
4254 : * Add filter clause into a list allowing caller to
4255 : * know if uniqueness have made not only by join
4256 : * clauses.
4257 : */
4258 : Assert(bms_is_empty(rinfo->left_relids) ||
4259 : bms_is_empty(rinfo->right_relids));
4260 46217 : if (extra_clauses)
4261 120 : exprs = lappend(exprs, rinfo);
4262 46217 : MemoryContextSwitchTo(oldMemCtx);
4263 : }
4264 :
4265 190023 : break; /* found a match; column is unique */
4266 : }
4267 : }
4268 :
4269 361552 : if (lc == NULL)
4270 171529 : break; /* no match; this index doesn't help us */
4271 : }
4272 :
4273 : /* Matched all key columns of this index? */
4274 278590 : if (c == ind->nkeycolumns)
4275 : {
4276 107061 : if (extra_clauses)
4277 513 : *extra_clauses = exprs;
4278 107061 : return true;
4279 : }
4280 : }
4281 :
4282 73920 : return false;
4283 : }
4284 :
4285 : /*
4286 : * indexcol_is_bool_constant_for_query
4287 : *
4288 : * If an index column is constrained to have a constant value by the query's
4289 : * WHERE conditions, then it's irrelevant for sort-order considerations.
4290 : * Usually that means we have a restriction clause WHERE indexcol = constant,
4291 : * which gets turned into an EquivalenceClass containing a constant, which
4292 : * is recognized as redundant by build_index_pathkeys(). But if the index
4293 : * column is a boolean variable (or expression), then we are not going to
4294 : * see WHERE indexcol = constant, because expression preprocessing will have
4295 : * simplified that to "WHERE indexcol" or "WHERE NOT indexcol". So we are not
4296 : * going to have a matching EquivalenceClass (unless the query also contains
4297 : * "ORDER BY indexcol"). To allow such cases to work the same as they would
4298 : * for non-boolean values, this function is provided to detect whether the
4299 : * specified index column matches a boolean restriction clause.
4300 : */
4301 : bool
4302 510222 : indexcol_is_bool_constant_for_query(PlannerInfo *root,
4303 : IndexOptInfo *index,
4304 : int indexcol)
4305 : {
4306 : ListCell *lc;
4307 :
4308 : /* If the index isn't boolean, we can't possibly get a match */
4309 510222 : if (!IsBooleanOpfamily(index->opfamily[indexcol]))
4310 506724 : return false;
4311 :
4312 : /* Check each restriction clause for the index's rel */
4313 3528 : foreach(lc, index->rel->baserestrictinfo)
4314 : {
4315 1298 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
4316 :
4317 : /*
4318 : * As in match_clause_to_indexcol, never match pseudoconstants to
4319 : * indexes. (It might be semantically okay to do so here, but the
4320 : * odds of getting a match are negligible, so don't waste the cycles.)
4321 : */
4322 1298 : if (rinfo->pseudoconstant)
4323 0 : continue;
4324 :
4325 : /* See if we can match the clause's expression to the index column */
4326 1298 : if (match_boolean_index_clause(root, rinfo, indexcol, index))
4327 1268 : return true;
4328 : }
4329 :
4330 2230 : return false;
4331 : }
4332 :
4333 :
4334 : /****************************************************************************
4335 : * ---- ROUTINES TO CHECK OPERANDS ----
4336 : ****************************************************************************/
4337 :
4338 : /*
4339 : * match_index_to_operand()
4340 : * Generalized test for a match between an index's key
4341 : * and the operand on one side of a restriction or join clause.
4342 : *
4343 : * operand: the nodetree to be compared to the index
4344 : * indexcol: the column number of the index (counting from 0)
4345 : * index: the index of interest
4346 : *
4347 : * Note that we aren't interested in collations here; the caller must check
4348 : * for a collation match, if it's dealing with an operator where that matters.
4349 : *
4350 : * This is exported for use in selfuncs.c.
4351 : */
4352 : bool
4353 2894748 : match_index_to_operand(Node *operand,
4354 : int indexcol,
4355 : IndexOptInfo *index)
4356 : {
4357 : int indkey;
4358 :
4359 : /*
4360 : * Ignore any PlaceHolderVar node contained in the operand. This is
4361 : * needed to be able to apply indexscanning in cases where the operand (or
4362 : * a subtree) has been wrapped in PlaceHolderVars to enforce separate
4363 : * identity or as a result of outer joins.
4364 : */
4365 2894748 : operand = strip_noop_phvs(operand);
4366 :
4367 : /*
4368 : * Ignore any RelabelType node above the operand. This is needed to be
4369 : * able to apply indexscanning in binary-compatible-operator cases.
4370 : *
4371 : * Note: we must handle nested RelabelType nodes here. While
4372 : * eval_const_expressions() will have simplified them to at most one
4373 : * layer, our prior stripping of PlaceHolderVars may have brought separate
4374 : * RelabelTypes into adjacency.
4375 : */
4376 2913897 : while (operand && IsA(operand, RelabelType))
4377 19149 : operand = (Node *) ((RelabelType *) operand)->arg;
4378 :
4379 2894748 : indkey = index->indexkeys[indexcol];
4380 2894748 : if (indkey != 0)
4381 : {
4382 : /*
4383 : * Simple index column; operand must be a matching Var.
4384 : */
4385 2889817 : if (operand && IsA(operand, Var) &&
4386 2167209 : index->rel->relid == ((Var *) operand)->varno &&
4387 2005146 : indkey == ((Var *) operand)->varattno &&
4388 732856 : ((Var *) operand)->varnullingrels == NULL)
4389 731776 : return true;
4390 : }
4391 : else
4392 : {
4393 : /*
4394 : * Index expression; find the correct expression. (This search could
4395 : * be avoided, at the cost of complicating all the callers of this
4396 : * routine; doesn't seem worth it.)
4397 : */
4398 : ListCell *indexpr_item;
4399 : int i;
4400 : Node *indexkey;
4401 :
4402 4931 : indexpr_item = list_head(index->indexprs);
4403 4931 : for (i = 0; i < indexcol; i++)
4404 : {
4405 0 : if (index->indexkeys[i] == 0)
4406 : {
4407 0 : if (indexpr_item == NULL)
4408 0 : elog(ERROR, "wrong number of index expressions");
4409 0 : indexpr_item = lnext(index->indexprs, indexpr_item);
4410 : }
4411 : }
4412 4931 : if (indexpr_item == NULL)
4413 0 : elog(ERROR, "wrong number of index expressions");
4414 4931 : indexkey = (Node *) lfirst(indexpr_item);
4415 :
4416 : /*
4417 : * Does it match the operand? Again, strip any relabeling.
4418 : */
4419 4931 : if (indexkey && IsA(indexkey, RelabelType))
4420 5 : indexkey = (Node *) ((RelabelType *) indexkey)->arg;
4421 :
4422 4931 : if (equal(indexkey, operand))
4423 1690 : return true;
4424 : }
4425 :
4426 2161282 : return false;
4427 : }
4428 :
4429 : /*
4430 : * is_pseudo_constant_for_index()
4431 : * Test whether the given expression can be used as an indexscan
4432 : * comparison value.
4433 : *
4434 : * An indexscan comparison value must not contain any volatile functions,
4435 : * and it can't contain any Vars of the index's own table. Vars of
4436 : * other tables are okay, though; in that case we'd be producing an
4437 : * indexqual usable in a parameterized indexscan. This is, therefore,
4438 : * a weaker condition than is_pseudo_constant_clause().
4439 : *
4440 : * This function is exported for use by planner support functions,
4441 : * which will have available the IndexOptInfo, but not any RestrictInfo
4442 : * infrastructure. It is making the same test made by functions above
4443 : * such as match_opclause_to_indexcol(), but those rely where possible
4444 : * on RestrictInfo information about variable membership.
4445 : *
4446 : * expr: the nodetree to be checked
4447 : * index: the index of interest
4448 : */
4449 : bool
4450 0 : is_pseudo_constant_for_index(PlannerInfo *root, Node *expr, IndexOptInfo *index)
4451 : {
4452 : /* pull_varnos is cheaper than volatility check, so do that first */
4453 0 : if (bms_is_member(index->rel->relid, pull_varnos(root, expr)))
4454 0 : return false; /* no good, contains Var of table */
4455 0 : if (contain_volatile_functions(expr))
4456 0 : return false; /* no good, volatile comparison value */
4457 0 : return true;
4458 : }
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