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) 1996-2024, PostgreSQL Global Development Group
8 : * Portions Copyright (c) 1994, Regents of the University of California
9 : *
10 : *
11 : * IDENTIFICATION
12 : * src/backend/optimizer/path/indxpath.c
13 : *
14 : *-------------------------------------------------------------------------
15 : */
16 : #include "postgres.h"
17 :
18 : #include <math.h>
19 :
20 : #include "access/stratnum.h"
21 : #include "access/sysattr.h"
22 : #include "catalog/pg_am.h"
23 : #include "catalog/pg_operator.h"
24 : #include "catalog/pg_opfamily.h"
25 : #include "catalog/pg_type.h"
26 : #include "nodes/makefuncs.h"
27 : #include "nodes/nodeFuncs.h"
28 : #include "nodes/supportnodes.h"
29 : #include "optimizer/cost.h"
30 : #include "optimizer/optimizer.h"
31 : #include "optimizer/pathnode.h"
32 : #include "optimizer/paths.h"
33 : #include "optimizer/prep.h"
34 : #include "optimizer/restrictinfo.h"
35 : #include "utils/lsyscache.h"
36 : #include "utils/selfuncs.h"
37 :
38 :
39 : /* XXX see PartCollMatchesExprColl */
40 : #define IndexCollMatchesExprColl(idxcollation, exprcollation) \
41 : ((idxcollation) == InvalidOid || (idxcollation) == (exprcollation))
42 :
43 : /* Whether we are looking for plain indexscan, bitmap scan, or either */
44 : typedef enum
45 : {
46 : ST_INDEXSCAN, /* must support amgettuple */
47 : ST_BITMAPSCAN, /* must support amgetbitmap */
48 : ST_ANYSCAN, /* either is okay */
49 : } ScanTypeControl;
50 :
51 : /* Data structure for collecting qual clauses that match an index */
52 : typedef struct
53 : {
54 : bool nonempty; /* True if lists are not all empty */
55 : /* Lists of IndexClause nodes, one list per index column */
56 : List *indexclauses[INDEX_MAX_KEYS];
57 : } IndexClauseSet;
58 :
59 : /* Per-path data used within choose_bitmap_and() */
60 : typedef struct
61 : {
62 : Path *path; /* IndexPath, BitmapAndPath, or BitmapOrPath */
63 : List *quals; /* the WHERE clauses it uses */
64 : List *preds; /* predicates of its partial index(es) */
65 : Bitmapset *clauseids; /* quals+preds represented as a bitmapset */
66 : bool unclassifiable; /* has too many quals+preds to process? */
67 : } PathClauseUsage;
68 :
69 : /* Callback argument for ec_member_matches_indexcol */
70 : typedef struct
71 : {
72 : IndexOptInfo *index; /* index we're considering */
73 : int indexcol; /* index column we want to match to */
74 : } ec_member_matches_arg;
75 :
76 :
77 : static void consider_index_join_clauses(PlannerInfo *root, RelOptInfo *rel,
78 : IndexOptInfo *index,
79 : IndexClauseSet *rclauseset,
80 : IndexClauseSet *jclauseset,
81 : IndexClauseSet *eclauseset,
82 : List **bitindexpaths);
83 : static void consider_index_join_outer_rels(PlannerInfo *root, RelOptInfo *rel,
84 : IndexOptInfo *index,
85 : IndexClauseSet *rclauseset,
86 : IndexClauseSet *jclauseset,
87 : IndexClauseSet *eclauseset,
88 : List **bitindexpaths,
89 : List *indexjoinclauses,
90 : int considered_clauses,
91 : List **considered_relids);
92 : static void get_join_index_paths(PlannerInfo *root, RelOptInfo *rel,
93 : IndexOptInfo *index,
94 : IndexClauseSet *rclauseset,
95 : IndexClauseSet *jclauseset,
96 : IndexClauseSet *eclauseset,
97 : List **bitindexpaths,
98 : Relids relids,
99 : List **considered_relids);
100 : static bool eclass_already_used(EquivalenceClass *parent_ec, Relids oldrelids,
101 : List *indexjoinclauses);
102 : static void get_index_paths(PlannerInfo *root, RelOptInfo *rel,
103 : IndexOptInfo *index, IndexClauseSet *clauses,
104 : List **bitindexpaths);
105 : static List *build_index_paths(PlannerInfo *root, RelOptInfo *rel,
106 : IndexOptInfo *index, IndexClauseSet *clauses,
107 : bool useful_predicate,
108 : ScanTypeControl scantype,
109 : bool *skip_nonnative_saop);
110 : static List *build_paths_for_OR(PlannerInfo *root, RelOptInfo *rel,
111 : List *clauses, List *other_clauses);
112 : static List *generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel,
113 : List *clauses, List *other_clauses);
114 : static Path *choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel,
115 : List *paths);
116 : static int path_usage_comparator(const void *a, const void *b);
117 : static Cost bitmap_scan_cost_est(PlannerInfo *root, RelOptInfo *rel,
118 : Path *ipath);
119 : static Cost bitmap_and_cost_est(PlannerInfo *root, RelOptInfo *rel,
120 : List *paths);
121 : static PathClauseUsage *classify_index_clause_usage(Path *path,
122 : List **clauselist);
123 : static void find_indexpath_quals(Path *bitmapqual, List **quals, List **preds);
124 : static int find_list_position(Node *node, List **nodelist);
125 : static bool check_index_only(RelOptInfo *rel, IndexOptInfo *index);
126 : static double get_loop_count(PlannerInfo *root, Index cur_relid, Relids outer_relids);
127 : static double adjust_rowcount_for_semijoins(PlannerInfo *root,
128 : Index cur_relid,
129 : Index outer_relid,
130 : double rowcount);
131 : static double approximate_joinrel_size(PlannerInfo *root, Relids relids);
132 : static void match_restriction_clauses_to_index(PlannerInfo *root,
133 : IndexOptInfo *index,
134 : IndexClauseSet *clauseset);
135 : static void match_join_clauses_to_index(PlannerInfo *root,
136 : RelOptInfo *rel, IndexOptInfo *index,
137 : IndexClauseSet *clauseset,
138 : List **joinorclauses);
139 : static void match_eclass_clauses_to_index(PlannerInfo *root,
140 : IndexOptInfo *index,
141 : IndexClauseSet *clauseset);
142 : static void match_clauses_to_index(PlannerInfo *root,
143 : List *clauses,
144 : IndexOptInfo *index,
145 : IndexClauseSet *clauseset);
146 : static void match_clause_to_index(PlannerInfo *root,
147 : RestrictInfo *rinfo,
148 : IndexOptInfo *index,
149 : IndexClauseSet *clauseset);
150 : static IndexClause *match_clause_to_indexcol(PlannerInfo *root,
151 : RestrictInfo *rinfo,
152 : int indexcol,
153 : IndexOptInfo *index);
154 : static bool IsBooleanOpfamily(Oid opfamily);
155 : static IndexClause *match_boolean_index_clause(PlannerInfo *root,
156 : RestrictInfo *rinfo,
157 : int indexcol, IndexOptInfo *index);
158 : static IndexClause *match_opclause_to_indexcol(PlannerInfo *root,
159 : RestrictInfo *rinfo,
160 : int indexcol,
161 : IndexOptInfo *index);
162 : static IndexClause *match_funcclause_to_indexcol(PlannerInfo *root,
163 : RestrictInfo *rinfo,
164 : int indexcol,
165 : IndexOptInfo *index);
166 : static IndexClause *get_index_clause_from_support(PlannerInfo *root,
167 : RestrictInfo *rinfo,
168 : Oid funcid,
169 : int indexarg,
170 : int indexcol,
171 : IndexOptInfo *index);
172 : static IndexClause *match_saopclause_to_indexcol(PlannerInfo *root,
173 : RestrictInfo *rinfo,
174 : int indexcol,
175 : IndexOptInfo *index);
176 : static IndexClause *match_rowcompare_to_indexcol(PlannerInfo *root,
177 : RestrictInfo *rinfo,
178 : int indexcol,
179 : IndexOptInfo *index);
180 : static IndexClause *expand_indexqual_rowcompare(PlannerInfo *root,
181 : RestrictInfo *rinfo,
182 : int indexcol,
183 : IndexOptInfo *index,
184 : Oid expr_op,
185 : bool var_on_left);
186 : static void match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys,
187 : List **orderby_clauses_p,
188 : List **clause_columns_p);
189 : static Expr *match_clause_to_ordering_op(IndexOptInfo *index,
190 : int indexcol, Expr *clause, Oid pk_opfamily);
191 : static bool ec_member_matches_indexcol(PlannerInfo *root, RelOptInfo *rel,
192 : EquivalenceClass *ec, EquivalenceMember *em,
193 : void *arg);
194 :
195 :
196 : /*
197 : * create_index_paths()
198 : * Generate all interesting index paths for the given relation.
199 : * Candidate paths are added to the rel's pathlist (using add_path).
200 : *
201 : * To be considered for an index scan, an index must match one or more
202 : * restriction clauses or join clauses from the query's qual condition,
203 : * or match the query's ORDER BY condition, or have a predicate that
204 : * matches the query's qual condition.
205 : *
206 : * There are two basic kinds of index scans. A "plain" index scan uses
207 : * only restriction clauses (possibly none at all) in its indexqual,
208 : * so it can be applied in any context. A "parameterized" index scan uses
209 : * join clauses (plus restriction clauses, if available) in its indexqual.
210 : * When joining such a scan to one of the relations supplying the other
211 : * variables used in its indexqual, the parameterized scan must appear as
212 : * the inner relation of a nestloop join; it can't be used on the outer side,
213 : * nor in a merge or hash join. In that context, values for the other rels'
214 : * attributes are available and fixed during any one scan of the indexpath.
215 : *
216 : * An IndexPath is generated and submitted to add_path() for each plain or
217 : * parameterized index scan this routine deems potentially interesting for
218 : * the current query.
219 : *
220 : * 'rel' is the relation for which we want to generate index paths
221 : *
222 : * Note: check_index_predicates() must have been run previously for this rel.
223 : *
224 : * Note: in cases involving LATERAL references in the relation's tlist, it's
225 : * possible that rel->lateral_relids is nonempty. Currently, we include
226 : * lateral_relids into the parameterization reported for each path, but don't
227 : * take it into account otherwise. The fact that any such rels *must* be
228 : * available as parameter sources perhaps should influence our choices of
229 : * index quals ... but for now, it doesn't seem worth troubling over.
230 : * In particular, comments below about "unparameterized" paths should be read
231 : * as meaning "unparameterized so far as the indexquals are concerned".
232 : */
233 : void
234 348602 : create_index_paths(PlannerInfo *root, RelOptInfo *rel)
235 : {
236 : List *indexpaths;
237 : List *bitindexpaths;
238 : List *bitjoinpaths;
239 : List *joinorclauses;
240 : IndexClauseSet rclauseset;
241 : IndexClauseSet jclauseset;
242 : IndexClauseSet eclauseset;
243 : ListCell *lc;
244 :
245 : /* Skip the whole mess if no indexes */
246 348602 : if (rel->indexlist == NIL)
247 67186 : return;
248 :
249 : /* Bitmap paths are collected and then dealt with at the end */
250 281416 : bitindexpaths = bitjoinpaths = joinorclauses = NIL;
251 :
252 : /* Examine each index in turn */
253 882696 : foreach(lc, rel->indexlist)
254 : {
255 601280 : IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
256 :
257 : /* Protect limited-size array in IndexClauseSets */
258 : Assert(index->nkeycolumns <= INDEX_MAX_KEYS);
259 :
260 : /*
261 : * Ignore partial indexes that do not match the query.
262 : * (generate_bitmap_or_paths() might be able to do something with
263 : * them, but that's of no concern here.)
264 : */
265 601280 : if (index->indpred != NIL && !index->predOK)
266 478 : continue;
267 :
268 : /*
269 : * Identify the restriction clauses that can match the index.
270 : */
271 20427268 : MemSet(&rclauseset, 0, sizeof(rclauseset));
272 600802 : match_restriction_clauses_to_index(root, index, &rclauseset);
273 :
274 : /*
275 : * Build index paths from the restriction clauses. These will be
276 : * non-parameterized paths. Plain paths go directly to add_path(),
277 : * bitmap paths are added to bitindexpaths to be handled below.
278 : */
279 600802 : get_index_paths(root, rel, index, &rclauseset,
280 : &bitindexpaths);
281 :
282 : /*
283 : * Identify the join clauses that can match the index. For the moment
284 : * we keep them separate from the restriction clauses. Note that this
285 : * step finds only "loose" join clauses that have not been merged into
286 : * EquivalenceClasses. Also, collect join OR clauses for later.
287 : */
288 20427268 : MemSet(&jclauseset, 0, sizeof(jclauseset));
289 600802 : match_join_clauses_to_index(root, rel, index,
290 : &jclauseset, &joinorclauses);
291 :
292 : /*
293 : * Look for EquivalenceClasses that can generate joinclauses matching
294 : * the index.
295 : */
296 20427268 : MemSet(&eclauseset, 0, sizeof(eclauseset));
297 600802 : match_eclass_clauses_to_index(root, index,
298 : &eclauseset);
299 :
300 : /*
301 : * If we found any plain or eclass join clauses, build parameterized
302 : * index paths using them.
303 : */
304 600802 : if (jclauseset.nonempty || eclauseset.nonempty)
305 107236 : consider_index_join_clauses(root, rel, index,
306 : &rclauseset,
307 : &jclauseset,
308 : &eclauseset,
309 : &bitjoinpaths);
310 : }
311 :
312 : /*
313 : * Generate BitmapOrPaths for any suitable OR-clauses present in the
314 : * restriction list. Add these to bitindexpaths.
315 : */
316 281416 : indexpaths = generate_bitmap_or_paths(root, rel,
317 : rel->baserestrictinfo, NIL);
318 281416 : bitindexpaths = list_concat(bitindexpaths, indexpaths);
319 :
320 : /*
321 : * Likewise, generate BitmapOrPaths for any suitable OR-clauses present in
322 : * the joinclause list. Add these to bitjoinpaths.
323 : */
324 281416 : indexpaths = generate_bitmap_or_paths(root, rel,
325 : joinorclauses, rel->baserestrictinfo);
326 281416 : bitjoinpaths = list_concat(bitjoinpaths, indexpaths);
327 :
328 : /*
329 : * If we found anything usable, generate a BitmapHeapPath for the most
330 : * promising combination of restriction bitmap index paths. Note there
331 : * will be only one such path no matter how many indexes exist. This
332 : * should be sufficient since there's basically only one figure of merit
333 : * (total cost) for such a path.
334 : */
335 281416 : if (bitindexpaths != NIL)
336 : {
337 : Path *bitmapqual;
338 : BitmapHeapPath *bpath;
339 :
340 177170 : bitmapqual = choose_bitmap_and(root, rel, bitindexpaths);
341 177170 : bpath = create_bitmap_heap_path(root, rel, bitmapqual,
342 : rel->lateral_relids, 1.0, 0);
343 177170 : add_path(rel, (Path *) bpath);
344 :
345 : /* create a partial bitmap heap path */
346 177170 : if (rel->consider_parallel && rel->lateral_relids == NULL)
347 127604 : create_partial_bitmap_paths(root, rel, bitmapqual);
348 : }
349 :
350 : /*
351 : * Likewise, if we found anything usable, generate BitmapHeapPaths for the
352 : * most promising combinations of join bitmap index paths. Our strategy
353 : * is to generate one such path for each distinct parameterization seen
354 : * among the available bitmap index paths. This may look pretty
355 : * expensive, but usually there won't be very many distinct
356 : * parameterizations. (This logic is quite similar to that in
357 : * consider_index_join_clauses, but we're working with whole paths not
358 : * individual clauses.)
359 : */
360 281416 : if (bitjoinpaths != NIL)
361 : {
362 : List *all_path_outers;
363 :
364 : /* Identify each distinct parameterization seen in bitjoinpaths */
365 98562 : all_path_outers = NIL;
366 215740 : foreach(lc, bitjoinpaths)
367 : {
368 117178 : Path *path = (Path *) lfirst(lc);
369 117178 : Relids required_outer = PATH_REQ_OUTER(path);
370 :
371 117178 : all_path_outers = list_append_unique(all_path_outers,
372 : required_outer);
373 : }
374 :
375 : /* Now, for each distinct parameterization set ... */
376 210486 : foreach(lc, all_path_outers)
377 : {
378 111924 : Relids max_outers = (Relids) lfirst(lc);
379 : List *this_path_set;
380 : Path *bitmapqual;
381 : Relids required_outer;
382 : double loop_count;
383 : BitmapHeapPath *bpath;
384 : ListCell *lcp;
385 :
386 : /* Identify all the bitmap join paths needing no more than that */
387 111924 : this_path_set = NIL;
388 265424 : foreach(lcp, bitjoinpaths)
389 : {
390 153500 : Path *path = (Path *) lfirst(lcp);
391 :
392 153500 : if (bms_is_subset(PATH_REQ_OUTER(path), max_outers))
393 123530 : this_path_set = lappend(this_path_set, path);
394 : }
395 :
396 : /*
397 : * Add in restriction bitmap paths, since they can be used
398 : * together with any join paths.
399 : */
400 111924 : this_path_set = list_concat(this_path_set, bitindexpaths);
401 :
402 : /* Select best AND combination for this parameterization */
403 111924 : bitmapqual = choose_bitmap_and(root, rel, this_path_set);
404 :
405 : /* And push that path into the mix */
406 111924 : required_outer = PATH_REQ_OUTER(bitmapqual);
407 111924 : loop_count = get_loop_count(root, rel->relid, required_outer);
408 111924 : bpath = create_bitmap_heap_path(root, rel, bitmapqual,
409 : required_outer, loop_count, 0);
410 111924 : add_path(rel, (Path *) bpath);
411 : }
412 : }
413 : }
414 :
415 : /*
416 : * consider_index_join_clauses
417 : * Given sets of join clauses for an index, decide which parameterized
418 : * index paths to build.
419 : *
420 : * Plain indexpaths are sent directly to add_path, while potential
421 : * bitmap indexpaths are added to *bitindexpaths for later processing.
422 : *
423 : * 'rel' is the index's heap relation
424 : * 'index' is the index for which we want to generate paths
425 : * 'rclauseset' is the collection of indexable restriction clauses
426 : * 'jclauseset' is the collection of indexable simple join clauses
427 : * 'eclauseset' is the collection of indexable clauses from EquivalenceClasses
428 : * '*bitindexpaths' is the list to add bitmap paths to
429 : */
430 : static void
431 107236 : consider_index_join_clauses(PlannerInfo *root, RelOptInfo *rel,
432 : IndexOptInfo *index,
433 : IndexClauseSet *rclauseset,
434 : IndexClauseSet *jclauseset,
435 : IndexClauseSet *eclauseset,
436 : List **bitindexpaths)
437 : {
438 107236 : int considered_clauses = 0;
439 107236 : List *considered_relids = NIL;
440 : int indexcol;
441 :
442 : /*
443 : * The strategy here is to identify every potentially useful set of outer
444 : * rels that can provide indexable join clauses. For each such set,
445 : * select all the join clauses available from those outer rels, add on all
446 : * the indexable restriction clauses, and generate plain and/or bitmap
447 : * index paths for that set of clauses. This is based on the assumption
448 : * that it's always better to apply a clause as an indexqual than as a
449 : * filter (qpqual); which is where an available clause would end up being
450 : * applied if we omit it from the indexquals.
451 : *
452 : * This looks expensive, but in most practical cases there won't be very
453 : * many distinct sets of outer rels to consider. As a safety valve when
454 : * that's not true, we use a heuristic: limit the number of outer rel sets
455 : * considered to a multiple of the number of clauses considered. (We'll
456 : * always consider using each individual join clause, though.)
457 : *
458 : * For simplicity in selecting relevant clauses, we represent each set of
459 : * outer rels as a maximum set of clause_relids --- that is, the indexed
460 : * relation itself is also included in the relids set. considered_relids
461 : * lists all relids sets we've already tried.
462 : */
463 260908 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
464 : {
465 : /* Consider each applicable simple join clause */
466 153672 : considered_clauses += list_length(jclauseset->indexclauses[indexcol]);
467 153672 : consider_index_join_outer_rels(root, rel, index,
468 : rclauseset, jclauseset, eclauseset,
469 : bitindexpaths,
470 : jclauseset->indexclauses[indexcol],
471 : considered_clauses,
472 : &considered_relids);
473 : /* Consider each applicable eclass join clause */
474 153672 : considered_clauses += list_length(eclauseset->indexclauses[indexcol]);
475 153672 : consider_index_join_outer_rels(root, rel, index,
476 : rclauseset, jclauseset, eclauseset,
477 : bitindexpaths,
478 : eclauseset->indexclauses[indexcol],
479 : considered_clauses,
480 : &considered_relids);
481 : }
482 107236 : }
483 :
484 : /*
485 : * consider_index_join_outer_rels
486 : * Generate parameterized paths based on clause relids in the clause list.
487 : *
488 : * Workhorse for consider_index_join_clauses; see notes therein for rationale.
489 : *
490 : * 'rel', 'index', 'rclauseset', 'jclauseset', 'eclauseset', and
491 : * 'bitindexpaths' as above
492 : * 'indexjoinclauses' is a list of IndexClauses for join clauses
493 : * 'considered_clauses' is the total number of clauses considered (so far)
494 : * '*considered_relids' is a list of all relids sets already considered
495 : */
496 : static void
497 307344 : consider_index_join_outer_rels(PlannerInfo *root, RelOptInfo *rel,
498 : IndexOptInfo *index,
499 : IndexClauseSet *rclauseset,
500 : IndexClauseSet *jclauseset,
501 : IndexClauseSet *eclauseset,
502 : List **bitindexpaths,
503 : List *indexjoinclauses,
504 : int considered_clauses,
505 : List **considered_relids)
506 : {
507 : ListCell *lc;
508 :
509 : /* Examine relids of each joinclause in the given list */
510 422642 : foreach(lc, indexjoinclauses)
511 : {
512 115298 : IndexClause *iclause = (IndexClause *) lfirst(lc);
513 115298 : Relids clause_relids = iclause->rinfo->clause_relids;
514 115298 : EquivalenceClass *parent_ec = iclause->rinfo->parent_ec;
515 : int num_considered_relids;
516 :
517 : /* If we already tried its relids set, no need to do so again */
518 115298 : if (list_member(*considered_relids, clause_relids))
519 1440 : continue;
520 :
521 : /*
522 : * Generate the union of this clause's relids set with each
523 : * previously-tried set. This ensures we try this clause along with
524 : * every interesting subset of previous clauses. However, to avoid
525 : * exponential growth of planning time when there are many clauses,
526 : * limit the number of relid sets accepted to 10 * considered_clauses.
527 : *
528 : * Note: get_join_index_paths appends entries to *considered_relids,
529 : * but we do not need to visit such newly-added entries within this
530 : * loop, so we don't use foreach() here. No real harm would be done
531 : * if we did visit them, since the subset check would reject them; but
532 : * it would waste some cycles.
533 : */
534 113858 : num_considered_relids = list_length(*considered_relids);
535 120720 : for (int pos = 0; pos < num_considered_relids; pos++)
536 : {
537 6862 : Relids oldrelids = (Relids) list_nth(*considered_relids, pos);
538 :
539 : /*
540 : * If either is a subset of the other, no new set is possible.
541 : * This isn't a complete test for redundancy, but it's easy and
542 : * cheap. get_join_index_paths will check more carefully if we
543 : * already generated the same relids set.
544 : */
545 6862 : if (bms_subset_compare(clause_relids, oldrelids) != BMS_DIFFERENT)
546 24 : continue;
547 :
548 : /*
549 : * If this clause was derived from an equivalence class, the
550 : * clause list may contain other clauses derived from the same
551 : * eclass. We should not consider that combining this clause with
552 : * one of those clauses generates a usefully different
553 : * parameterization; so skip if any clause derived from the same
554 : * eclass would already have been included when using oldrelids.
555 : */
556 13524 : if (parent_ec &&
557 6686 : eclass_already_used(parent_ec, oldrelids,
558 : indexjoinclauses))
559 3818 : continue;
560 :
561 : /*
562 : * If the number of relid sets considered exceeds our heuristic
563 : * limit, stop considering combinations of clauses. We'll still
564 : * consider the current clause alone, though (below this loop).
565 : */
566 3020 : if (list_length(*considered_relids) >= 10 * considered_clauses)
567 0 : break;
568 :
569 : /* OK, try the union set */
570 3020 : get_join_index_paths(root, rel, index,
571 : rclauseset, jclauseset, eclauseset,
572 : bitindexpaths,
573 : bms_union(clause_relids, oldrelids),
574 : considered_relids);
575 : }
576 :
577 : /* Also try this set of relids by itself */
578 113858 : get_join_index_paths(root, rel, index,
579 : rclauseset, jclauseset, eclauseset,
580 : bitindexpaths,
581 : clause_relids,
582 : considered_relids);
583 : }
584 307344 : }
585 :
586 : /*
587 : * get_join_index_paths
588 : * Generate index paths using clauses from the specified outer relations.
589 : * In addition to generating paths, relids is added to *considered_relids
590 : * if not already present.
591 : *
592 : * Workhorse for consider_index_join_clauses; see notes therein for rationale.
593 : *
594 : * 'rel', 'index', 'rclauseset', 'jclauseset', 'eclauseset',
595 : * 'bitindexpaths', 'considered_relids' as above
596 : * 'relids' is the current set of relids to consider (the target rel plus
597 : * one or more outer rels)
598 : */
599 : static void
600 116878 : get_join_index_paths(PlannerInfo *root, RelOptInfo *rel,
601 : IndexOptInfo *index,
602 : IndexClauseSet *rclauseset,
603 : IndexClauseSet *jclauseset,
604 : IndexClauseSet *eclauseset,
605 : List **bitindexpaths,
606 : Relids relids,
607 : List **considered_relids)
608 : {
609 : IndexClauseSet clauseset;
610 : int indexcol;
611 :
612 : /* If we already considered this relids set, don't repeat the work */
613 116878 : if (list_member(*considered_relids, relids))
614 0 : return;
615 :
616 : /* Identify indexclauses usable with this relids set */
617 3973852 : MemSet(&clauseset, 0, sizeof(clauseset));
618 :
619 288552 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
620 : {
621 : ListCell *lc;
622 :
623 : /* First find applicable simple join clauses */
624 205316 : foreach(lc, jclauseset->indexclauses[indexcol])
625 : {
626 33642 : IndexClause *iclause = (IndexClause *) lfirst(lc);
627 :
628 33642 : if (bms_is_subset(iclause->rinfo->clause_relids, relids))
629 33262 : clauseset.indexclauses[indexcol] =
630 33262 : lappend(clauseset.indexclauses[indexcol], iclause);
631 : }
632 :
633 : /*
634 : * Add applicable eclass join clauses. The clauses generated for each
635 : * column are redundant (cf generate_implied_equalities_for_column),
636 : * so we need at most one. This is the only exception to the general
637 : * rule of using all available index clauses.
638 : */
639 181752 : foreach(lc, eclauseset->indexclauses[indexcol])
640 : {
641 98118 : IndexClause *iclause = (IndexClause *) lfirst(lc);
642 :
643 98118 : if (bms_is_subset(iclause->rinfo->clause_relids, relids))
644 : {
645 88040 : clauseset.indexclauses[indexcol] =
646 88040 : lappend(clauseset.indexclauses[indexcol], iclause);
647 88040 : break;
648 : }
649 : }
650 :
651 : /* Add restriction clauses */
652 171674 : clauseset.indexclauses[indexcol] =
653 171674 : list_concat(clauseset.indexclauses[indexcol],
654 171674 : rclauseset->indexclauses[indexcol]);
655 :
656 171674 : if (clauseset.indexclauses[indexcol] != NIL)
657 141180 : clauseset.nonempty = true;
658 : }
659 :
660 : /* We should have found something, else caller passed silly relids */
661 : Assert(clauseset.nonempty);
662 :
663 : /* Build index path(s) using the collected set of clauses */
664 116878 : get_index_paths(root, rel, index, &clauseset, bitindexpaths);
665 :
666 : /*
667 : * Remember we considered paths for this set of relids.
668 : */
669 116878 : *considered_relids = lappend(*considered_relids, relids);
670 : }
671 :
672 : /*
673 : * eclass_already_used
674 : * True if any join clause usable with oldrelids was generated from
675 : * the specified equivalence class.
676 : */
677 : static bool
678 6686 : eclass_already_used(EquivalenceClass *parent_ec, Relids oldrelids,
679 : List *indexjoinclauses)
680 : {
681 : ListCell *lc;
682 :
683 9848 : foreach(lc, indexjoinclauses)
684 : {
685 6980 : IndexClause *iclause = (IndexClause *) lfirst(lc);
686 6980 : RestrictInfo *rinfo = iclause->rinfo;
687 :
688 13960 : if (rinfo->parent_ec == parent_ec &&
689 6980 : bms_is_subset(rinfo->clause_relids, oldrelids))
690 3818 : return true;
691 : }
692 2868 : return false;
693 : }
694 :
695 :
696 : /*
697 : * get_index_paths
698 : * Given an index and a set of index clauses for it, construct IndexPaths.
699 : *
700 : * Plain indexpaths are sent directly to add_path, while potential
701 : * bitmap indexpaths are added to *bitindexpaths for later processing.
702 : *
703 : * This is a fairly simple frontend to build_index_paths(). Its reason for
704 : * existence is mainly to handle ScalarArrayOpExpr quals properly. If the
705 : * index AM supports them natively, we should just include them in simple
706 : * index paths. If not, we should exclude them while building simple index
707 : * paths, and then make a separate attempt to include them in bitmap paths.
708 : */
709 : static void
710 717680 : get_index_paths(PlannerInfo *root, RelOptInfo *rel,
711 : IndexOptInfo *index, IndexClauseSet *clauses,
712 : List **bitindexpaths)
713 : {
714 : List *indexpaths;
715 717680 : bool skip_nonnative_saop = false;
716 : ListCell *lc;
717 :
718 : /*
719 : * Build simple index paths using the clauses. Allow ScalarArrayOpExpr
720 : * clauses only if the index AM supports them natively.
721 : */
722 717680 : indexpaths = build_index_paths(root, rel,
723 : index, clauses,
724 717680 : index->predOK,
725 : ST_ANYSCAN,
726 : &skip_nonnative_saop);
727 :
728 : /*
729 : * Submit all the ones that can form plain IndexScan plans to add_path. (A
730 : * plain IndexPath can represent either a plain IndexScan or an
731 : * IndexOnlyScan, but for our purposes here that distinction does not
732 : * matter. However, some of the indexes might support only bitmap scans,
733 : * and those we mustn't submit to add_path here.)
734 : *
735 : * Also, pick out the ones that are usable as bitmap scans. For that, we
736 : * must discard indexes that don't support bitmap scans, and we also are
737 : * only interested in paths that have some selectivity; we should discard
738 : * anything that was generated solely for ordering purposes.
739 : */
740 1140924 : foreach(lc, indexpaths)
741 : {
742 423244 : IndexPath *ipath = (IndexPath *) lfirst(lc);
743 :
744 423244 : if (index->amhasgettuple)
745 409854 : add_path(rel, (Path *) ipath);
746 :
747 423244 : if (index->amhasgetbitmap &&
748 423244 : (ipath->path.pathkeys == NIL ||
749 252616 : ipath->indexselectivity < 1.0))
750 311932 : *bitindexpaths = lappend(*bitindexpaths, ipath);
751 : }
752 :
753 : /*
754 : * If there were ScalarArrayOpExpr clauses that the index can't handle
755 : * natively, generate bitmap scan paths relying on executor-managed
756 : * ScalarArrayOpExpr.
757 : */
758 717680 : if (skip_nonnative_saop)
759 : {
760 32 : indexpaths = build_index_paths(root, rel,
761 : index, clauses,
762 : false,
763 : ST_BITMAPSCAN,
764 : NULL);
765 32 : *bitindexpaths = list_concat(*bitindexpaths, indexpaths);
766 : }
767 717680 : }
768 :
769 : /*
770 : * build_index_paths
771 : * Given an index and a set of index clauses for it, construct zero
772 : * or more IndexPaths. It also constructs zero or more partial IndexPaths.
773 : *
774 : * We return a list of paths because (1) this routine checks some cases
775 : * that should cause us to not generate any IndexPath, and (2) in some
776 : * cases we want to consider both a forward and a backward scan, so as
777 : * to obtain both sort orders. Note that the paths are just returned
778 : * to the caller and not immediately fed to add_path().
779 : *
780 : * At top level, useful_predicate should be exactly the index's predOK flag
781 : * (ie, true if it has a predicate that was proven from the restriction
782 : * clauses). When working on an arm of an OR clause, useful_predicate
783 : * should be true if the predicate required the current OR list to be proven.
784 : * Note that this routine should never be called at all if the index has an
785 : * unprovable predicate.
786 : *
787 : * scantype indicates whether we want to create plain indexscans, bitmap
788 : * indexscans, or both. When it's ST_BITMAPSCAN, we will not consider
789 : * index ordering while deciding if a Path is worth generating.
790 : *
791 : * If skip_nonnative_saop is non-NULL, we ignore ScalarArrayOpExpr clauses
792 : * unless the index AM supports them directly, and we set *skip_nonnative_saop
793 : * to true if we found any such clauses (caller must initialize the variable
794 : * to false). If it's NULL, we do not ignore ScalarArrayOpExpr clauses.
795 : *
796 : * 'rel' is the index's heap relation
797 : * 'index' is the index for which we want to generate paths
798 : * 'clauses' is the collection of indexable clauses (IndexClause nodes)
799 : * 'useful_predicate' indicates whether the index has a useful predicate
800 : * 'scantype' indicates whether we need plain or bitmap scan support
801 : * 'skip_nonnative_saop' indicates whether to accept SAOP if index AM doesn't
802 : */
803 : static List *
804 720390 : build_index_paths(PlannerInfo *root, RelOptInfo *rel,
805 : IndexOptInfo *index, IndexClauseSet *clauses,
806 : bool useful_predicate,
807 : ScanTypeControl scantype,
808 : bool *skip_nonnative_saop)
809 : {
810 720390 : List *result = NIL;
811 : IndexPath *ipath;
812 : List *index_clauses;
813 : Relids outer_relids;
814 : double loop_count;
815 : List *orderbyclauses;
816 : List *orderbyclausecols;
817 : List *index_pathkeys;
818 : List *useful_pathkeys;
819 : bool pathkeys_possibly_useful;
820 : bool index_is_ordered;
821 : bool index_only_scan;
822 : int indexcol;
823 :
824 : Assert(skip_nonnative_saop != NULL || scantype == ST_BITMAPSCAN);
825 :
826 : /*
827 : * Check that index supports the desired scan type(s)
828 : */
829 720390 : switch (scantype)
830 : {
831 0 : case ST_INDEXSCAN:
832 0 : if (!index->amhasgettuple)
833 0 : return NIL;
834 0 : break;
835 2710 : case ST_BITMAPSCAN:
836 2710 : if (!index->amhasgetbitmap)
837 0 : return NIL;
838 2710 : break;
839 717680 : case ST_ANYSCAN:
840 : /* either or both are OK */
841 717680 : break;
842 : }
843 :
844 : /*
845 : * 1. Combine the per-column IndexClause lists into an overall list.
846 : *
847 : * In the resulting list, clauses are ordered by index key, so that the
848 : * column numbers form a nondecreasing sequence. (This order is depended
849 : * on by btree and possibly other places.) The list can be empty, if the
850 : * index AM allows that.
851 : *
852 : * We also build a Relids set showing which outer rels are required by the
853 : * selected clauses. Any lateral_relids are included in that, but not
854 : * otherwise accounted for.
855 : */
856 720390 : index_clauses = NIL;
857 720390 : outer_relids = bms_copy(rel->lateral_relids);
858 2059442 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
859 : {
860 : ListCell *lc;
861 :
862 1698400 : foreach(lc, clauses->indexclauses[indexcol])
863 : {
864 359054 : IndexClause *iclause = (IndexClause *) lfirst(lc);
865 359054 : RestrictInfo *rinfo = iclause->rinfo;
866 :
867 359054 : if (skip_nonnative_saop && !index->amsearcharray &&
868 20868 : IsA(rinfo->clause, ScalarArrayOpExpr))
869 : {
870 : /*
871 : * Caller asked us to generate IndexPaths that omit any
872 : * ScalarArrayOpExpr clauses when the underlying index AM
873 : * lacks native support.
874 : *
875 : * We must omit this clause (and tell caller about it).
876 : */
877 32 : *skip_nonnative_saop = true;
878 32 : continue;
879 : }
880 :
881 : /* OK to include this clause */
882 359022 : index_clauses = lappend(index_clauses, iclause);
883 359022 : outer_relids = bms_add_members(outer_relids,
884 359022 : rinfo->clause_relids);
885 : }
886 :
887 : /*
888 : * If no clauses match the first index column, check for amoptionalkey
889 : * restriction. We can't generate a scan over an index with
890 : * amoptionalkey = false unless there's at least one index clause.
891 : * (When working on columns after the first, this test cannot fail. It
892 : * is always okay for columns after the first to not have any
893 : * clauses.)
894 : */
895 1339346 : if (index_clauses == NIL && !index->amoptionalkey)
896 294 : return NIL;
897 : }
898 :
899 : /* We do not want the index's rel itself listed in outer_relids */
900 720096 : outer_relids = bms_del_member(outer_relids, rel->relid);
901 :
902 : /* Compute loop_count for cost estimation purposes */
903 720096 : loop_count = get_loop_count(root, rel->relid, outer_relids);
904 :
905 : /*
906 : * 2. Compute pathkeys describing index's ordering, if any, then see how
907 : * many of them are actually useful for this query. This is not relevant
908 : * if we are only trying to build bitmap indexscans.
909 : */
910 1437482 : pathkeys_possibly_useful = (scantype != ST_BITMAPSCAN &&
911 717386 : has_useful_pathkeys(root, rel));
912 720096 : index_is_ordered = (index->sortopfamily != NULL);
913 720096 : if (index_is_ordered && pathkeys_possibly_useful)
914 : {
915 530568 : index_pathkeys = build_index_pathkeys(root, index,
916 : ForwardScanDirection);
917 530568 : useful_pathkeys = truncate_useless_pathkeys(root, rel,
918 : index_pathkeys);
919 530568 : orderbyclauses = NIL;
920 530568 : orderbyclausecols = NIL;
921 : }
922 189528 : else if (index->amcanorderbyop && pathkeys_possibly_useful)
923 : {
924 : /*
925 : * See if we can generate ordering operators for query_pathkeys or at
926 : * least some prefix thereof. Matching to just a prefix of the
927 : * query_pathkeys will allow an incremental sort to be considered on
928 : * the index's partially sorted results.
929 : */
930 862 : match_pathkeys_to_index(index, root->query_pathkeys,
931 : &orderbyclauses,
932 : &orderbyclausecols);
933 862 : if (list_length(root->query_pathkeys) == list_length(orderbyclauses))
934 474 : useful_pathkeys = root->query_pathkeys;
935 : else
936 388 : useful_pathkeys = list_copy_head(root->query_pathkeys,
937 : list_length(orderbyclauses));
938 : }
939 : else
940 : {
941 188666 : useful_pathkeys = NIL;
942 188666 : orderbyclauses = NIL;
943 188666 : orderbyclausecols = NIL;
944 : }
945 :
946 : /*
947 : * 3. Check if an index-only scan is possible. If we're not building
948 : * plain indexscans, this isn't relevant since bitmap scans don't support
949 : * index data retrieval anyway.
950 : */
951 1437482 : index_only_scan = (scantype != ST_BITMAPSCAN &&
952 717386 : check_index_only(rel, index));
953 :
954 : /*
955 : * 4. Generate an indexscan path if there are relevant restriction clauses
956 : * in the current clauses, OR the index ordering is potentially useful for
957 : * later merging or final output ordering, OR the index has a useful
958 : * predicate, OR an index-only scan is possible.
959 : */
960 720096 : if (index_clauses != NIL || useful_pathkeys != NIL || useful_predicate ||
961 : index_only_scan)
962 : {
963 425424 : ipath = create_index_path(root, index,
964 : index_clauses,
965 : orderbyclauses,
966 : orderbyclausecols,
967 : useful_pathkeys,
968 : ForwardScanDirection,
969 : index_only_scan,
970 : outer_relids,
971 : loop_count,
972 : false);
973 425424 : result = lappend(result, ipath);
974 :
975 : /*
976 : * If appropriate, consider parallel index scan. We don't allow
977 : * parallel index scan for bitmap index scans.
978 : */
979 425424 : if (index->amcanparallel &&
980 405356 : rel->consider_parallel && outer_relids == NULL &&
981 : scantype != ST_BITMAPSCAN)
982 : {
983 223436 : ipath = create_index_path(root, index,
984 : index_clauses,
985 : orderbyclauses,
986 : orderbyclausecols,
987 : useful_pathkeys,
988 : ForwardScanDirection,
989 : index_only_scan,
990 : outer_relids,
991 : loop_count,
992 : true);
993 :
994 : /*
995 : * if, after costing the path, we find that it's not worth using
996 : * parallel workers, just free it.
997 : */
998 223436 : if (ipath->path.parallel_workers > 0)
999 9618 : add_partial_path(rel, (Path *) ipath);
1000 : else
1001 213818 : pfree(ipath);
1002 : }
1003 : }
1004 :
1005 : /*
1006 : * 5. If the index is ordered, a backwards scan might be interesting.
1007 : */
1008 720096 : if (index_is_ordered && pathkeys_possibly_useful)
1009 : {
1010 530568 : index_pathkeys = build_index_pathkeys(root, index,
1011 : BackwardScanDirection);
1012 530568 : useful_pathkeys = truncate_useless_pathkeys(root, rel,
1013 : index_pathkeys);
1014 530568 : if (useful_pathkeys != NIL)
1015 : {
1016 530 : ipath = create_index_path(root, index,
1017 : index_clauses,
1018 : NIL,
1019 : NIL,
1020 : useful_pathkeys,
1021 : BackwardScanDirection,
1022 : index_only_scan,
1023 : outer_relids,
1024 : loop_count,
1025 : false);
1026 530 : result = lappend(result, ipath);
1027 :
1028 : /* If appropriate, consider parallel index scan */
1029 530 : if (index->amcanparallel &&
1030 530 : rel->consider_parallel && outer_relids == NULL &&
1031 : scantype != ST_BITMAPSCAN)
1032 : {
1033 440 : ipath = create_index_path(root, index,
1034 : index_clauses,
1035 : NIL,
1036 : NIL,
1037 : useful_pathkeys,
1038 : BackwardScanDirection,
1039 : index_only_scan,
1040 : outer_relids,
1041 : loop_count,
1042 : true);
1043 :
1044 : /*
1045 : * if, after costing the path, we find that it's not worth
1046 : * using parallel workers, just free it.
1047 : */
1048 440 : if (ipath->path.parallel_workers > 0)
1049 168 : add_partial_path(rel, (Path *) ipath);
1050 : else
1051 272 : pfree(ipath);
1052 : }
1053 : }
1054 : }
1055 :
1056 720096 : return result;
1057 : }
1058 :
1059 : /*
1060 : * build_paths_for_OR
1061 : * Given a list of restriction clauses from one arm of an OR clause,
1062 : * construct all matching IndexPaths for the relation.
1063 : *
1064 : * Here we must scan all indexes of the relation, since a bitmap OR tree
1065 : * can use multiple indexes.
1066 : *
1067 : * The caller actually supplies two lists of restriction clauses: some
1068 : * "current" ones and some "other" ones. Both lists can be used freely
1069 : * to match keys of the index, but an index must use at least one of the
1070 : * "current" clauses to be considered usable. The motivation for this is
1071 : * examples like
1072 : * WHERE (x = 42) AND (... OR (y = 52 AND z = 77) OR ....)
1073 : * While we are considering the y/z subclause of the OR, we can use "x = 42"
1074 : * as one of the available index conditions; but we shouldn't match the
1075 : * subclause to any index on x alone, because such a Path would already have
1076 : * been generated at the upper level. So we could use an index on x,y,z
1077 : * or an index on x,y for the OR subclause, but not an index on just x.
1078 : * When dealing with a partial index, a match of the index predicate to
1079 : * one of the "current" clauses also makes the index usable.
1080 : *
1081 : * 'rel' is the relation for which we want to generate index paths
1082 : * 'clauses' is the current list of clauses (RestrictInfo nodes)
1083 : * 'other_clauses' is the list of additional upper-level clauses
1084 : */
1085 : static List *
1086 14476 : build_paths_for_OR(PlannerInfo *root, RelOptInfo *rel,
1087 : List *clauses, List *other_clauses)
1088 : {
1089 14476 : List *result = NIL;
1090 14476 : List *all_clauses = NIL; /* not computed till needed */
1091 : ListCell *lc;
1092 :
1093 49592 : foreach(lc, rel->indexlist)
1094 : {
1095 35116 : IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
1096 : IndexClauseSet clauseset;
1097 : List *indexpaths;
1098 : bool useful_predicate;
1099 :
1100 : /* Ignore index if it doesn't support bitmap scans */
1101 35116 : if (!index->amhasgetbitmap)
1102 32438 : continue;
1103 :
1104 : /*
1105 : * Ignore partial indexes that do not match the query. If a partial
1106 : * index is marked predOK then we know it's OK. Otherwise, we have to
1107 : * test whether the added clauses are sufficient to imply the
1108 : * predicate. If so, we can use the index in the current context.
1109 : *
1110 : * We set useful_predicate to true iff the predicate was proven using
1111 : * the current set of clauses. This is needed to prevent matching a
1112 : * predOK index to an arm of an OR, which would be a legal but
1113 : * pointlessly inefficient plan. (A better plan will be generated by
1114 : * just scanning the predOK index alone, no OR.)
1115 : */
1116 35116 : useful_predicate = false;
1117 35116 : if (index->indpred != NIL)
1118 : {
1119 144 : if (index->predOK)
1120 : {
1121 : /* Usable, but don't set useful_predicate */
1122 : }
1123 : else
1124 : {
1125 : /* Form all_clauses if not done already */
1126 120 : if (all_clauses == NIL)
1127 48 : all_clauses = list_concat_copy(clauses, other_clauses);
1128 :
1129 120 : if (!predicate_implied_by(index->indpred, all_clauses, false))
1130 84 : continue; /* can't use it at all */
1131 :
1132 36 : if (!predicate_implied_by(index->indpred, other_clauses, false))
1133 36 : useful_predicate = true;
1134 : }
1135 : }
1136 :
1137 : /*
1138 : * Identify the restriction clauses that can match the index.
1139 : */
1140 1191088 : MemSet(&clauseset, 0, sizeof(clauseset));
1141 35032 : match_clauses_to_index(root, clauses, index, &clauseset);
1142 :
1143 : /*
1144 : * If no matches so far, and the index predicate isn't useful, we
1145 : * don't want it.
1146 : */
1147 35032 : if (!clauseset.nonempty && !useful_predicate)
1148 32354 : continue;
1149 :
1150 : /*
1151 : * Add "other" restriction clauses to the clauseset.
1152 : */
1153 2678 : match_clauses_to_index(root, other_clauses, index, &clauseset);
1154 :
1155 : /*
1156 : * Construct paths if possible.
1157 : */
1158 2678 : indexpaths = build_index_paths(root, rel,
1159 : index, &clauseset,
1160 : useful_predicate,
1161 : ST_BITMAPSCAN,
1162 : NULL);
1163 2678 : result = list_concat(result, indexpaths);
1164 : }
1165 :
1166 14476 : return result;
1167 : }
1168 :
1169 : /*
1170 : * generate_bitmap_or_paths
1171 : * Look through the list of clauses to find OR clauses, and generate
1172 : * a BitmapOrPath for each one we can handle that way. Return a list
1173 : * of the generated BitmapOrPaths.
1174 : *
1175 : * other_clauses is a list of additional clauses that can be assumed true
1176 : * for the purpose of generating indexquals, but are not to be searched for
1177 : * ORs. (See build_paths_for_OR() for motivation.)
1178 : */
1179 : static List *
1180 565092 : generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel,
1181 : List *clauses, List *other_clauses)
1182 : {
1183 565092 : List *result = NIL;
1184 : List *all_clauses;
1185 : ListCell *lc;
1186 :
1187 : /*
1188 : * We can use both the current and other clauses as context for
1189 : * build_paths_for_OR; no need to remove ORs from the lists.
1190 : */
1191 565092 : all_clauses = list_concat_copy(clauses, other_clauses);
1192 :
1193 889998 : foreach(lc, clauses)
1194 : {
1195 324906 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
1196 : List *pathlist;
1197 : Path *bitmapqual;
1198 : ListCell *j;
1199 :
1200 : /* Ignore RestrictInfos that aren't ORs */
1201 324906 : if (!restriction_is_or_clause(rinfo))
1202 311902 : continue;
1203 :
1204 : /*
1205 : * We must be able to match at least one index to each of the arms of
1206 : * the OR, else we can't use it.
1207 : */
1208 13004 : pathlist = NIL;
1209 15436 : foreach(j, ((BoolExpr *) rinfo->orclause)->args)
1210 : {
1211 14476 : Node *orarg = (Node *) lfirst(j);
1212 : List *indlist;
1213 :
1214 : /* OR arguments should be ANDs or sub-RestrictInfos */
1215 14476 : if (is_andclause(orarg))
1216 : {
1217 2260 : List *andargs = ((BoolExpr *) orarg)->args;
1218 :
1219 2260 : indlist = build_paths_for_OR(root, rel,
1220 : andargs,
1221 : all_clauses);
1222 :
1223 : /* Recurse in case there are sub-ORs */
1224 2260 : indlist = list_concat(indlist,
1225 2260 : generate_bitmap_or_paths(root, rel,
1226 : andargs,
1227 : all_clauses));
1228 : }
1229 : else
1230 : {
1231 12216 : RestrictInfo *ri = castNode(RestrictInfo, orarg);
1232 : List *orargs;
1233 :
1234 : Assert(!restriction_is_or_clause(ri));
1235 12216 : orargs = list_make1(ri);
1236 :
1237 12216 : indlist = build_paths_for_OR(root, rel,
1238 : orargs,
1239 : all_clauses);
1240 : }
1241 :
1242 : /*
1243 : * If nothing matched this arm, we can't do anything with this OR
1244 : * clause.
1245 : */
1246 14476 : if (indlist == NIL)
1247 : {
1248 12044 : pathlist = NIL;
1249 12044 : break;
1250 : }
1251 :
1252 : /*
1253 : * OK, pick the most promising AND combination, and add it to
1254 : * pathlist.
1255 : */
1256 2432 : bitmapqual = choose_bitmap_and(root, rel, indlist);
1257 2432 : pathlist = lappend(pathlist, bitmapqual);
1258 : }
1259 :
1260 : /*
1261 : * If we have a match for every arm, then turn them into a
1262 : * BitmapOrPath, and add to result list.
1263 : */
1264 13004 : if (pathlist != NIL)
1265 : {
1266 960 : bitmapqual = (Path *) create_bitmap_or_path(root, rel, pathlist);
1267 960 : result = lappend(result, bitmapqual);
1268 : }
1269 : }
1270 :
1271 565092 : return result;
1272 : }
1273 :
1274 :
1275 : /*
1276 : * choose_bitmap_and
1277 : * Given a nonempty list of bitmap paths, AND them into one path.
1278 : *
1279 : * This is a nontrivial decision since we can legally use any subset of the
1280 : * given path set. We want to choose a good tradeoff between selectivity
1281 : * and cost of computing the bitmap.
1282 : *
1283 : * The result is either a single one of the inputs, or a BitmapAndPath
1284 : * combining multiple inputs.
1285 : */
1286 : static Path *
1287 291526 : choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel, List *paths)
1288 : {
1289 291526 : int npaths = list_length(paths);
1290 : PathClauseUsage **pathinfoarray;
1291 : PathClauseUsage *pathinfo;
1292 : List *clauselist;
1293 291526 : List *bestpaths = NIL;
1294 291526 : Cost bestcost = 0;
1295 : int i,
1296 : j;
1297 : ListCell *l;
1298 :
1299 : Assert(npaths > 0); /* else caller error */
1300 291526 : if (npaths == 1)
1301 234466 : return (Path *) linitial(paths); /* easy case */
1302 :
1303 : /*
1304 : * In theory we should consider every nonempty subset of the given paths.
1305 : * In practice that seems like overkill, given the crude nature of the
1306 : * estimates, not to mention the possible effects of higher-level AND and
1307 : * OR clauses. Moreover, it's completely impractical if there are a large
1308 : * number of paths, since the work would grow as O(2^N).
1309 : *
1310 : * As a heuristic, we first check for paths using exactly the same sets of
1311 : * WHERE clauses + index predicate conditions, and reject all but the
1312 : * cheapest-to-scan in any such group. This primarily gets rid of indexes
1313 : * that include the interesting columns but also irrelevant columns. (In
1314 : * situations where the DBA has gone overboard on creating variant
1315 : * indexes, this can make for a very large reduction in the number of
1316 : * paths considered further.)
1317 : *
1318 : * We then sort the surviving paths with the cheapest-to-scan first, and
1319 : * for each path, consider using that path alone as the basis for a bitmap
1320 : * scan. Then we consider bitmap AND scans formed from that path plus
1321 : * each subsequent (higher-cost) path, adding on a subsequent path if it
1322 : * results in a reduction in the estimated total scan cost. This means we
1323 : * consider about O(N^2) rather than O(2^N) path combinations, which is
1324 : * quite tolerable, especially given than N is usually reasonably small
1325 : * because of the prefiltering step. The cheapest of these is returned.
1326 : *
1327 : * We will only consider AND combinations in which no two indexes use the
1328 : * same WHERE clause. This is a bit of a kluge: it's needed because
1329 : * costsize.c and clausesel.c aren't very smart about redundant clauses.
1330 : * They will usually double-count the redundant clauses, producing a
1331 : * too-small selectivity that makes a redundant AND step look like it
1332 : * reduces the total cost. Perhaps someday that code will be smarter and
1333 : * we can remove this limitation. (But note that this also defends
1334 : * against flat-out duplicate input paths, which can happen because
1335 : * match_join_clauses_to_index will find the same OR join clauses that
1336 : * extract_restriction_or_clauses has pulled OR restriction clauses out
1337 : * of.)
1338 : *
1339 : * For the same reason, we reject AND combinations in which an index
1340 : * predicate clause duplicates another clause. Here we find it necessary
1341 : * to be even stricter: we'll reject a partial index if any of its
1342 : * predicate clauses are implied by the set of WHERE clauses and predicate
1343 : * clauses used so far. This covers cases such as a condition "x = 42"
1344 : * used with a plain index, followed by a clauseless scan of a partial
1345 : * index "WHERE x >= 40 AND x < 50". The partial index has been accepted
1346 : * only because "x = 42" was present, and so allowing it would partially
1347 : * double-count selectivity. (We could use predicate_implied_by on
1348 : * regular qual clauses too, to have a more intelligent, but much more
1349 : * expensive, check for redundancy --- but in most cases simple equality
1350 : * seems to suffice.)
1351 : */
1352 :
1353 : /*
1354 : * Extract clause usage info and detect any paths that use exactly the
1355 : * same set of clauses; keep only the cheapest-to-scan of any such groups.
1356 : * The surviving paths are put into an array for qsort'ing.
1357 : */
1358 : pathinfoarray = (PathClauseUsage **)
1359 57060 : palloc(npaths * sizeof(PathClauseUsage *));
1360 57060 : clauselist = NIL;
1361 57060 : npaths = 0;
1362 188402 : foreach(l, paths)
1363 : {
1364 131342 : Path *ipath = (Path *) lfirst(l);
1365 :
1366 131342 : pathinfo = classify_index_clause_usage(ipath, &clauselist);
1367 :
1368 : /* If it's unclassifiable, treat it as distinct from all others */
1369 131342 : if (pathinfo->unclassifiable)
1370 : {
1371 0 : pathinfoarray[npaths++] = pathinfo;
1372 0 : continue;
1373 : }
1374 :
1375 205796 : for (i = 0; i < npaths; i++)
1376 : {
1377 182604 : if (!pathinfoarray[i]->unclassifiable &&
1378 91302 : bms_equal(pathinfo->clauseids, pathinfoarray[i]->clauseids))
1379 16848 : break;
1380 : }
1381 131342 : if (i < npaths)
1382 : {
1383 : /* duplicate clauseids, keep the cheaper one */
1384 : Cost ncost;
1385 : Cost ocost;
1386 : Selectivity nselec;
1387 : Selectivity oselec;
1388 :
1389 16848 : cost_bitmap_tree_node(pathinfo->path, &ncost, &nselec);
1390 16848 : cost_bitmap_tree_node(pathinfoarray[i]->path, &ocost, &oselec);
1391 16848 : if (ncost < ocost)
1392 2576 : pathinfoarray[i] = pathinfo;
1393 : }
1394 : else
1395 : {
1396 : /* not duplicate clauseids, add to array */
1397 114494 : pathinfoarray[npaths++] = pathinfo;
1398 : }
1399 : }
1400 :
1401 : /* If only one surviving path, we're done */
1402 57060 : if (npaths == 1)
1403 10000 : return pathinfoarray[0]->path;
1404 :
1405 : /* Sort the surviving paths by index access cost */
1406 47060 : qsort(pathinfoarray, npaths, sizeof(PathClauseUsage *),
1407 : path_usage_comparator);
1408 :
1409 : /*
1410 : * For each surviving index, consider it as an "AND group leader", and see
1411 : * whether adding on any of the later indexes results in an AND path with
1412 : * cheaper total cost than before. Then take the cheapest AND group.
1413 : *
1414 : * Note: paths that are either clauseless or unclassifiable will have
1415 : * empty clauseids, so that they will not be rejected by the clauseids
1416 : * filter here, nor will they cause later paths to be rejected by it.
1417 : */
1418 151554 : for (i = 0; i < npaths; i++)
1419 : {
1420 : Cost costsofar;
1421 : List *qualsofar;
1422 : Bitmapset *clauseidsofar;
1423 :
1424 104494 : pathinfo = pathinfoarray[i];
1425 104494 : paths = list_make1(pathinfo->path);
1426 104494 : costsofar = bitmap_scan_cost_est(root, rel, pathinfo->path);
1427 104494 : qualsofar = list_concat_copy(pathinfo->quals, pathinfo->preds);
1428 104494 : clauseidsofar = bms_copy(pathinfo->clauseids);
1429 :
1430 172758 : for (j = i + 1; j < npaths; j++)
1431 : {
1432 : Cost newcost;
1433 :
1434 68264 : pathinfo = pathinfoarray[j];
1435 : /* Check for redundancy */
1436 68264 : if (bms_overlap(pathinfo->clauseids, clauseidsofar))
1437 34200 : continue; /* consider it redundant */
1438 34064 : if (pathinfo->preds)
1439 : {
1440 24 : bool redundant = false;
1441 :
1442 : /* we check each predicate clause separately */
1443 24 : foreach(l, pathinfo->preds)
1444 : {
1445 24 : Node *np = (Node *) lfirst(l);
1446 :
1447 24 : if (predicate_implied_by(list_make1(np), qualsofar, false))
1448 : {
1449 24 : redundant = true;
1450 24 : break; /* out of inner foreach loop */
1451 : }
1452 : }
1453 24 : if (redundant)
1454 24 : continue;
1455 : }
1456 : /* tentatively add new path to paths, so we can estimate cost */
1457 34040 : paths = lappend(paths, pathinfo->path);
1458 34040 : newcost = bitmap_and_cost_est(root, rel, paths);
1459 34040 : if (newcost < costsofar)
1460 : {
1461 : /* keep new path in paths, update subsidiary variables */
1462 152 : costsofar = newcost;
1463 152 : qualsofar = list_concat(qualsofar, pathinfo->quals);
1464 152 : qualsofar = list_concat(qualsofar, pathinfo->preds);
1465 152 : clauseidsofar = bms_add_members(clauseidsofar,
1466 152 : pathinfo->clauseids);
1467 : }
1468 : else
1469 : {
1470 : /* reject new path, remove it from paths list */
1471 33888 : paths = list_truncate(paths, list_length(paths) - 1);
1472 : }
1473 : }
1474 :
1475 : /* Keep the cheapest AND-group (or singleton) */
1476 104494 : if (i == 0 || costsofar < bestcost)
1477 : {
1478 49806 : bestpaths = paths;
1479 49806 : bestcost = costsofar;
1480 : }
1481 :
1482 : /* some easy cleanup (we don't try real hard though) */
1483 104494 : list_free(qualsofar);
1484 : }
1485 :
1486 47060 : if (list_length(bestpaths) == 1)
1487 46932 : return (Path *) linitial(bestpaths); /* no need for AND */
1488 128 : return (Path *) create_bitmap_and_path(root, rel, bestpaths);
1489 : }
1490 :
1491 : /* qsort comparator to sort in increasing index access cost order */
1492 : static int
1493 64050 : path_usage_comparator(const void *a, const void *b)
1494 : {
1495 64050 : PathClauseUsage *pa = *(PathClauseUsage *const *) a;
1496 64050 : PathClauseUsage *pb = *(PathClauseUsage *const *) b;
1497 : Cost acost;
1498 : Cost bcost;
1499 : Selectivity aselec;
1500 : Selectivity bselec;
1501 :
1502 64050 : cost_bitmap_tree_node(pa->path, &acost, &aselec);
1503 64050 : cost_bitmap_tree_node(pb->path, &bcost, &bselec);
1504 :
1505 : /*
1506 : * If costs are the same, sort by selectivity.
1507 : */
1508 64050 : if (acost < bcost)
1509 36426 : return -1;
1510 27624 : if (acost > bcost)
1511 18634 : return 1;
1512 :
1513 8990 : if (aselec < bselec)
1514 4510 : return -1;
1515 4480 : if (aselec > bselec)
1516 636 : return 1;
1517 :
1518 3844 : return 0;
1519 : }
1520 :
1521 : /*
1522 : * Estimate the cost of actually executing a bitmap scan with a single
1523 : * index path (which could be a BitmapAnd or BitmapOr node).
1524 : */
1525 : static Cost
1526 138534 : bitmap_scan_cost_est(PlannerInfo *root, RelOptInfo *rel, Path *ipath)
1527 : {
1528 : BitmapHeapPath bpath;
1529 :
1530 : /* Set up a dummy BitmapHeapPath */
1531 138534 : bpath.path.type = T_BitmapHeapPath;
1532 138534 : bpath.path.pathtype = T_BitmapHeapScan;
1533 138534 : bpath.path.parent = rel;
1534 138534 : bpath.path.pathtarget = rel->reltarget;
1535 138534 : bpath.path.param_info = ipath->param_info;
1536 138534 : bpath.path.pathkeys = NIL;
1537 138534 : bpath.bitmapqual = ipath;
1538 :
1539 : /*
1540 : * Check the cost of temporary path without considering parallelism.
1541 : * Parallel bitmap heap path will be considered at later stage.
1542 : */
1543 138534 : bpath.path.parallel_workers = 0;
1544 :
1545 : /* Now we can do cost_bitmap_heap_scan */
1546 138534 : cost_bitmap_heap_scan(&bpath.path, root, rel,
1547 : bpath.path.param_info,
1548 : ipath,
1549 : get_loop_count(root, rel->relid,
1550 138534 : PATH_REQ_OUTER(ipath)));
1551 :
1552 138534 : return bpath.path.total_cost;
1553 : }
1554 :
1555 : /*
1556 : * Estimate the cost of actually executing a BitmapAnd scan with the given
1557 : * inputs.
1558 : */
1559 : static Cost
1560 34040 : bitmap_and_cost_est(PlannerInfo *root, RelOptInfo *rel, List *paths)
1561 : {
1562 : BitmapAndPath *apath;
1563 :
1564 : /*
1565 : * Might as well build a real BitmapAndPath here, as the work is slightly
1566 : * too complicated to be worth repeating just to save one palloc.
1567 : */
1568 34040 : apath = create_bitmap_and_path(root, rel, paths);
1569 :
1570 34040 : return bitmap_scan_cost_est(root, rel, (Path *) apath);
1571 : }
1572 :
1573 :
1574 : /*
1575 : * classify_index_clause_usage
1576 : * Construct a PathClauseUsage struct describing the WHERE clauses and
1577 : * index predicate clauses used by the given indexscan path.
1578 : * We consider two clauses the same if they are equal().
1579 : *
1580 : * At some point we might want to migrate this info into the Path data
1581 : * structure proper, but for the moment it's only needed within
1582 : * choose_bitmap_and().
1583 : *
1584 : * *clauselist is used and expanded as needed to identify all the distinct
1585 : * clauses seen across successive calls. Caller must initialize it to NIL
1586 : * before first call of a set.
1587 : */
1588 : static PathClauseUsage *
1589 131342 : classify_index_clause_usage(Path *path, List **clauselist)
1590 : {
1591 : PathClauseUsage *result;
1592 : Bitmapset *clauseids;
1593 : ListCell *lc;
1594 :
1595 131342 : result = (PathClauseUsage *) palloc(sizeof(PathClauseUsage));
1596 131342 : result->path = path;
1597 :
1598 : /* Recursively find the quals and preds used by the path */
1599 131342 : result->quals = NIL;
1600 131342 : result->preds = NIL;
1601 131342 : find_indexpath_quals(path, &result->quals, &result->preds);
1602 :
1603 : /*
1604 : * Some machine-generated queries have outlandish numbers of qual clauses.
1605 : * To avoid getting into O(N^2) behavior even in this preliminary
1606 : * classification step, we want to limit the number of entries we can
1607 : * accumulate in *clauselist. Treat any path with more than 100 quals +
1608 : * preds as unclassifiable, which will cause calling code to consider it
1609 : * distinct from all other paths.
1610 : */
1611 131342 : if (list_length(result->quals) + list_length(result->preds) > 100)
1612 : {
1613 0 : result->clauseids = NULL;
1614 0 : result->unclassifiable = true;
1615 0 : return result;
1616 : }
1617 :
1618 : /* Build up a bitmapset representing the quals and preds */
1619 131342 : clauseids = NULL;
1620 300752 : foreach(lc, result->quals)
1621 : {
1622 169410 : Node *node = (Node *) lfirst(lc);
1623 :
1624 169410 : clauseids = bms_add_member(clauseids,
1625 : find_list_position(node, clauselist));
1626 : }
1627 131636 : foreach(lc, result->preds)
1628 : {
1629 294 : Node *node = (Node *) lfirst(lc);
1630 :
1631 294 : clauseids = bms_add_member(clauseids,
1632 : find_list_position(node, clauselist));
1633 : }
1634 131342 : result->clauseids = clauseids;
1635 131342 : result->unclassifiable = false;
1636 :
1637 131342 : return result;
1638 : }
1639 :
1640 :
1641 : /*
1642 : * find_indexpath_quals
1643 : *
1644 : * Given the Path structure for a plain or bitmap indexscan, extract lists
1645 : * of all the index clauses and index predicate conditions used in the Path.
1646 : * These are appended to the initial contents of *quals and *preds (hence
1647 : * caller should initialize those to NIL).
1648 : *
1649 : * Note we are not trying to produce an accurate representation of the AND/OR
1650 : * semantics of the Path, but just find out all the base conditions used.
1651 : *
1652 : * The result lists contain pointers to the expressions used in the Path,
1653 : * but all the list cells are freshly built, so it's safe to destructively
1654 : * modify the lists (eg, by concat'ing with other lists).
1655 : */
1656 : static void
1657 133988 : find_indexpath_quals(Path *bitmapqual, List **quals, List **preds)
1658 : {
1659 133988 : if (IsA(bitmapqual, BitmapAndPath))
1660 : {
1661 0 : BitmapAndPath *apath = (BitmapAndPath *) bitmapqual;
1662 : ListCell *l;
1663 :
1664 0 : foreach(l, apath->bitmapquals)
1665 : {
1666 0 : find_indexpath_quals((Path *) lfirst(l), quals, preds);
1667 : }
1668 : }
1669 133988 : else if (IsA(bitmapqual, BitmapOrPath))
1670 : {
1671 1290 : BitmapOrPath *opath = (BitmapOrPath *) bitmapqual;
1672 : ListCell *l;
1673 :
1674 3936 : foreach(l, opath->bitmapquals)
1675 : {
1676 2646 : find_indexpath_quals((Path *) lfirst(l), quals, preds);
1677 : }
1678 : }
1679 132698 : else if (IsA(bitmapqual, IndexPath))
1680 : {
1681 132698 : IndexPath *ipath = (IndexPath *) bitmapqual;
1682 : ListCell *l;
1683 :
1684 302108 : foreach(l, ipath->indexclauses)
1685 : {
1686 169410 : IndexClause *iclause = (IndexClause *) lfirst(l);
1687 :
1688 169410 : *quals = lappend(*quals, iclause->rinfo->clause);
1689 : }
1690 132698 : *preds = list_concat(*preds, ipath->indexinfo->indpred);
1691 : }
1692 : else
1693 0 : elog(ERROR, "unrecognized node type: %d", nodeTag(bitmapqual));
1694 133988 : }
1695 :
1696 :
1697 : /*
1698 : * find_list_position
1699 : * Return the given node's position (counting from 0) in the given
1700 : * list of nodes. If it's not equal() to any existing list member,
1701 : * add it at the end, and return that position.
1702 : */
1703 : static int
1704 169704 : find_list_position(Node *node, List **nodelist)
1705 : {
1706 : int i;
1707 : ListCell *lc;
1708 :
1709 169704 : i = 0;
1710 260584 : foreach(lc, *nodelist)
1711 : {
1712 144586 : Node *oldnode = (Node *) lfirst(lc);
1713 :
1714 144586 : if (equal(node, oldnode))
1715 53706 : return i;
1716 90880 : i++;
1717 : }
1718 :
1719 115998 : *nodelist = lappend(*nodelist, node);
1720 :
1721 115998 : return i;
1722 : }
1723 :
1724 :
1725 : /*
1726 : * check_index_only
1727 : * Determine whether an index-only scan is possible for this index.
1728 : */
1729 : static bool
1730 717386 : check_index_only(RelOptInfo *rel, IndexOptInfo *index)
1731 : {
1732 : bool result;
1733 717386 : Bitmapset *attrs_used = NULL;
1734 717386 : Bitmapset *index_canreturn_attrs = NULL;
1735 : ListCell *lc;
1736 : int i;
1737 :
1738 : /* Index-only scans must be enabled */
1739 717386 : if (!enable_indexonlyscan)
1740 3842 : return false;
1741 :
1742 : /*
1743 : * Check that all needed attributes of the relation are available from the
1744 : * index.
1745 : */
1746 :
1747 : /*
1748 : * First, identify all the attributes needed for joins or final output.
1749 : * Note: we must look at rel's targetlist, not the attr_needed data,
1750 : * because attr_needed isn't computed for inheritance child rels.
1751 : */
1752 713544 : pull_varattnos((Node *) rel->reltarget->exprs, rel->relid, &attrs_used);
1753 :
1754 : /*
1755 : * Add all the attributes used by restriction clauses; but consider only
1756 : * those clauses not implied by the index predicate, since ones that are
1757 : * so implied don't need to be checked explicitly in the plan.
1758 : *
1759 : * Note: attributes used only in index quals would not be needed at
1760 : * runtime either, if we are certain that the index is not lossy. However
1761 : * it'd be complicated to account for that accurately, and it doesn't
1762 : * matter in most cases, since we'd conclude that such attributes are
1763 : * available from the index anyway.
1764 : */
1765 1465690 : foreach(lc, index->indrestrictinfo)
1766 : {
1767 752146 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
1768 :
1769 752146 : pull_varattnos((Node *) rinfo->clause, rel->relid, &attrs_used);
1770 : }
1771 :
1772 : /*
1773 : * Construct a bitmapset of columns that the index can return back in an
1774 : * index-only scan.
1775 : */
1776 2044250 : for (i = 0; i < index->ncolumns; i++)
1777 : {
1778 1330706 : int attno = index->indexkeys[i];
1779 :
1780 : /*
1781 : * For the moment, we just ignore index expressions. It might be nice
1782 : * to do something with them, later.
1783 : */
1784 1330706 : if (attno == 0)
1785 3246 : continue;
1786 :
1787 1327460 : if (index->canreturn[i])
1788 : index_canreturn_attrs =
1789 1052714 : bms_add_member(index_canreturn_attrs,
1790 : attno - FirstLowInvalidHeapAttributeNumber);
1791 : }
1792 :
1793 : /* Do we have all the necessary attributes? */
1794 713544 : result = bms_is_subset(attrs_used, index_canreturn_attrs);
1795 :
1796 713544 : bms_free(attrs_used);
1797 713544 : bms_free(index_canreturn_attrs);
1798 :
1799 713544 : return result;
1800 : }
1801 :
1802 : /*
1803 : * get_loop_count
1804 : * Choose the loop count estimate to use for costing a parameterized path
1805 : * with the given set of outer relids.
1806 : *
1807 : * Since we produce parameterized paths before we've begun to generate join
1808 : * relations, it's impossible to predict exactly how many times a parameterized
1809 : * path will be iterated; we don't know the size of the relation that will be
1810 : * on the outside of the nestloop. However, we should try to account for
1811 : * multiple iterations somehow in costing the path. The heuristic embodied
1812 : * here is to use the rowcount of the smallest other base relation needed in
1813 : * the join clauses used by the path. (We could alternatively consider the
1814 : * largest one, but that seems too optimistic.) This is of course the right
1815 : * answer for single-other-relation cases, and it seems like a reasonable
1816 : * zero-order approximation for multiway-join cases.
1817 : *
1818 : * In addition, we check to see if the other side of each join clause is on
1819 : * the inside of some semijoin that the current relation is on the outside of.
1820 : * If so, the only way that a parameterized path could be used is if the
1821 : * semijoin RHS has been unique-ified, so we should use the number of unique
1822 : * RHS rows rather than using the relation's raw rowcount.
1823 : *
1824 : * Note: for this to work, allpaths.c must establish all baserel size
1825 : * estimates before it begins to compute paths, or at least before it
1826 : * calls create_index_paths().
1827 : */
1828 : static double
1829 970554 : get_loop_count(PlannerInfo *root, Index cur_relid, Relids outer_relids)
1830 : {
1831 : double result;
1832 : int outer_relid;
1833 :
1834 : /* For a non-parameterized path, just return 1.0 quickly */
1835 970554 : if (outer_relids == NULL)
1836 675892 : return 1.0;
1837 :
1838 294662 : result = 0.0;
1839 294662 : outer_relid = -1;
1840 599036 : while ((outer_relid = bms_next_member(outer_relids, outer_relid)) >= 0)
1841 : {
1842 : RelOptInfo *outer_rel;
1843 : double rowcount;
1844 :
1845 : /* Paranoia: ignore bogus relid indexes */
1846 304374 : if (outer_relid >= root->simple_rel_array_size)
1847 0 : continue;
1848 304374 : outer_rel = root->simple_rel_array[outer_relid];
1849 304374 : if (outer_rel == NULL)
1850 262 : continue;
1851 : Assert(outer_rel->relid == outer_relid); /* sanity check on array */
1852 :
1853 : /* Other relation could be proven empty, if so ignore */
1854 304112 : if (IS_DUMMY_REL(outer_rel))
1855 24 : continue;
1856 :
1857 : /* Otherwise, rel's rows estimate should be valid by now */
1858 : Assert(outer_rel->rows > 0);
1859 :
1860 : /* Check to see if rel is on the inside of any semijoins */
1861 304088 : rowcount = adjust_rowcount_for_semijoins(root,
1862 : cur_relid,
1863 : outer_relid,
1864 : outer_rel->rows);
1865 :
1866 : /* Remember smallest row count estimate among the outer rels */
1867 304088 : if (result == 0.0 || result > rowcount)
1868 300704 : result = rowcount;
1869 : }
1870 : /* Return 1.0 if we found no valid relations (shouldn't happen) */
1871 294662 : return (result > 0.0) ? result : 1.0;
1872 : }
1873 :
1874 : /*
1875 : * Check to see if outer_relid is on the inside of any semijoin that cur_relid
1876 : * is on the outside of. If so, replace rowcount with the estimated number of
1877 : * unique rows from the semijoin RHS (assuming that's smaller, which it might
1878 : * not be). The estimate is crude but it's the best we can do at this stage
1879 : * of the proceedings.
1880 : */
1881 : static double
1882 304088 : adjust_rowcount_for_semijoins(PlannerInfo *root,
1883 : Index cur_relid,
1884 : Index outer_relid,
1885 : double rowcount)
1886 : {
1887 : ListCell *lc;
1888 :
1889 504162 : foreach(lc, root->join_info_list)
1890 : {
1891 200074 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(lc);
1892 :
1893 206260 : if (sjinfo->jointype == JOIN_SEMI &&
1894 8410 : bms_is_member(cur_relid, sjinfo->syn_lefthand) &&
1895 2224 : bms_is_member(outer_relid, sjinfo->syn_righthand))
1896 : {
1897 : /* Estimate number of unique-ified rows */
1898 : double nraw;
1899 : double nunique;
1900 :
1901 872 : nraw = approximate_joinrel_size(root, sjinfo->syn_righthand);
1902 872 : nunique = estimate_num_groups(root,
1903 : sjinfo->semi_rhs_exprs,
1904 : nraw,
1905 : NULL,
1906 : NULL);
1907 872 : if (rowcount > nunique)
1908 354 : rowcount = nunique;
1909 : }
1910 : }
1911 304088 : return rowcount;
1912 : }
1913 :
1914 : /*
1915 : * Make an approximate estimate of the size of a joinrel.
1916 : *
1917 : * We don't have enough info at this point to get a good estimate, so we
1918 : * just multiply the base relation sizes together. Fortunately, this is
1919 : * the right answer anyway for the most common case with a single relation
1920 : * on the RHS of a semijoin. Also, estimate_num_groups() has only a weak
1921 : * dependency on its input_rows argument (it basically uses it as a clamp).
1922 : * So we might be able to get a fairly decent end result even with a severe
1923 : * overestimate of the RHS's raw size.
1924 : */
1925 : static double
1926 872 : approximate_joinrel_size(PlannerInfo *root, Relids relids)
1927 : {
1928 872 : double rowcount = 1.0;
1929 : int relid;
1930 :
1931 872 : relid = -1;
1932 1900 : while ((relid = bms_next_member(relids, relid)) >= 0)
1933 : {
1934 : RelOptInfo *rel;
1935 :
1936 : /* Paranoia: ignore bogus relid indexes */
1937 1028 : if (relid >= root->simple_rel_array_size)
1938 0 : continue;
1939 1028 : rel = root->simple_rel_array[relid];
1940 1028 : if (rel == NULL)
1941 0 : continue;
1942 : Assert(rel->relid == relid); /* sanity check on array */
1943 :
1944 : /* Relation could be proven empty, if so ignore */
1945 1028 : if (IS_DUMMY_REL(rel))
1946 0 : continue;
1947 :
1948 : /* Otherwise, rel's rows estimate should be valid by now */
1949 : Assert(rel->rows > 0);
1950 :
1951 : /* Accumulate product */
1952 1028 : rowcount *= rel->rows;
1953 : }
1954 872 : return rowcount;
1955 : }
1956 :
1957 :
1958 : /****************************************************************************
1959 : * ---- ROUTINES TO CHECK QUERY CLAUSES ----
1960 : ****************************************************************************/
1961 :
1962 : /*
1963 : * match_restriction_clauses_to_index
1964 : * Identify restriction clauses for the rel that match the index.
1965 : * Matching clauses are added to *clauseset.
1966 : */
1967 : static void
1968 600802 : match_restriction_clauses_to_index(PlannerInfo *root,
1969 : IndexOptInfo *index,
1970 : IndexClauseSet *clauseset)
1971 : {
1972 : /* We can ignore clauses that are implied by the index predicate */
1973 600802 : match_clauses_to_index(root, index->indrestrictinfo, index, clauseset);
1974 600802 : }
1975 :
1976 : /*
1977 : * match_join_clauses_to_index
1978 : * Identify join clauses for the rel that match the index.
1979 : * Matching clauses are added to *clauseset.
1980 : * Also, add any potentially usable join OR clauses to *joinorclauses.
1981 : */
1982 : static void
1983 600802 : match_join_clauses_to_index(PlannerInfo *root,
1984 : RelOptInfo *rel, IndexOptInfo *index,
1985 : IndexClauseSet *clauseset,
1986 : List **joinorclauses)
1987 : {
1988 : ListCell *lc;
1989 :
1990 : /* Scan the rel's join clauses */
1991 838816 : foreach(lc, rel->joininfo)
1992 : {
1993 238014 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
1994 :
1995 : /* Check if clause can be moved to this rel */
1996 238014 : if (!join_clause_is_movable_to(rinfo, rel))
1997 142166 : continue;
1998 :
1999 : /* Potentially usable, so see if it matches the index or is an OR */
2000 95848 : if (restriction_is_or_clause(rinfo))
2001 10698 : *joinorclauses = lappend(*joinorclauses, rinfo);
2002 : else
2003 85150 : match_clause_to_index(root, rinfo, index, clauseset);
2004 : }
2005 600802 : }
2006 :
2007 : /*
2008 : * match_eclass_clauses_to_index
2009 : * Identify EquivalenceClass join clauses for the rel that match the index.
2010 : * Matching clauses are added to *clauseset.
2011 : */
2012 : static void
2013 600802 : match_eclass_clauses_to_index(PlannerInfo *root, IndexOptInfo *index,
2014 : IndexClauseSet *clauseset)
2015 : {
2016 : int indexcol;
2017 :
2018 : /* No work if rel is not in any such ECs */
2019 600802 : if (!index->rel->has_eclass_joins)
2020 367472 : return;
2021 :
2022 597470 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
2023 : {
2024 : ec_member_matches_arg arg;
2025 : List *clauses;
2026 :
2027 : /* Generate clauses, skipping any that join to lateral_referencers */
2028 364140 : arg.index = index;
2029 364140 : arg.indexcol = indexcol;
2030 364140 : clauses = generate_implied_equalities_for_column(root,
2031 : index->rel,
2032 : ec_member_matches_indexcol,
2033 : (void *) &arg,
2034 364140 : index->rel->lateral_referencers);
2035 :
2036 : /*
2037 : * We have to check whether the results actually do match the index,
2038 : * since for non-btree indexes the EC's equality operators might not
2039 : * be in the index opclass (cf ec_member_matches_indexcol).
2040 : */
2041 364140 : match_clauses_to_index(root, clauses, index, clauseset);
2042 : }
2043 : }
2044 :
2045 : /*
2046 : * match_clauses_to_index
2047 : * Perform match_clause_to_index() for each clause in a list.
2048 : * Matching clauses are added to *clauseset.
2049 : */
2050 : static void
2051 1002652 : match_clauses_to_index(PlannerInfo *root,
2052 : List *clauses,
2053 : IndexOptInfo *index,
2054 : IndexClauseSet *clauseset)
2055 : {
2056 : ListCell *lc;
2057 :
2058 1823810 : foreach(lc, clauses)
2059 : {
2060 821158 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
2061 :
2062 821158 : match_clause_to_index(root, rinfo, index, clauseset);
2063 : }
2064 1002652 : }
2065 :
2066 : /*
2067 : * match_clause_to_index
2068 : * Test whether a qual clause can be used with an index.
2069 : *
2070 : * If the clause is usable, add an IndexClause entry for it to the appropriate
2071 : * list in *clauseset. (*clauseset must be initialized to zeroes before first
2072 : * call.)
2073 : *
2074 : * Note: in some circumstances we may find the same RestrictInfos coming from
2075 : * multiple places. Defend against redundant outputs by refusing to add a
2076 : * clause twice (pointer equality should be a good enough check for this).
2077 : *
2078 : * Note: it's possible that a badly-defined index could have multiple matching
2079 : * columns. We always select the first match if so; this avoids scenarios
2080 : * wherein we get an inflated idea of the index's selectivity by using the
2081 : * same clause multiple times with different index columns.
2082 : */
2083 : static void
2084 906308 : match_clause_to_index(PlannerInfo *root,
2085 : RestrictInfo *rinfo,
2086 : IndexOptInfo *index,
2087 : IndexClauseSet *clauseset)
2088 : {
2089 : int indexcol;
2090 :
2091 : /*
2092 : * Never match pseudoconstants to indexes. (Normally a match could not
2093 : * happen anyway, since a pseudoconstant clause couldn't contain a Var,
2094 : * but what if someone builds an expression index on a constant? It's not
2095 : * totally unreasonable to do so with a partial index, either.)
2096 : */
2097 906308 : if (rinfo->pseudoconstant)
2098 11656 : return;
2099 :
2100 : /*
2101 : * If clause can't be used as an indexqual because it must wait till after
2102 : * some lower-security-level restriction clause, reject it.
2103 : */
2104 894652 : if (!restriction_is_securely_promotable(rinfo, index->rel))
2105 474 : return;
2106 :
2107 : /* OK, check each index key column for a match */
2108 1978120 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
2109 : {
2110 : IndexClause *iclause;
2111 : ListCell *lc;
2112 :
2113 : /* Ignore duplicates */
2114 1474538 : foreach(lc, clauseset->indexclauses[indexcol])
2115 : {
2116 58102 : iclause = (IndexClause *) lfirst(lc);
2117 :
2118 58102 : if (iclause->rinfo == rinfo)
2119 0 : return;
2120 : }
2121 :
2122 : /* OK, try to match the clause to the index column */
2123 1416436 : iclause = match_clause_to_indexcol(root,
2124 : rinfo,
2125 : indexcol,
2126 : index);
2127 1416436 : if (iclause)
2128 : {
2129 : /* Success, so record it */
2130 332494 : clauseset->indexclauses[indexcol] =
2131 332494 : lappend(clauseset->indexclauses[indexcol], iclause);
2132 332494 : clauseset->nonempty = true;
2133 332494 : return;
2134 : }
2135 : }
2136 : }
2137 :
2138 : /*
2139 : * match_clause_to_indexcol()
2140 : * Determine whether a restriction clause matches a column of an index,
2141 : * and if so, build an IndexClause node describing the details.
2142 : *
2143 : * To match an index normally, an operator clause:
2144 : *
2145 : * (1) must be in the form (indexkey op const) or (const op indexkey);
2146 : * and
2147 : * (2) must contain an operator which is in the index's operator family
2148 : * for this column; and
2149 : * (3) must match the collation of the index, if collation is relevant.
2150 : *
2151 : * Our definition of "const" is exceedingly liberal: we allow anything that
2152 : * doesn't involve a volatile function or a Var of the index's relation.
2153 : * In particular, Vars belonging to other relations of the query are
2154 : * accepted here, since a clause of that form can be used in a
2155 : * parameterized indexscan. It's the responsibility of higher code levels
2156 : * to manage restriction and join clauses appropriately.
2157 : *
2158 : * Note: we do need to check for Vars of the index's relation on the
2159 : * "const" side of the clause, since clauses like (a.f1 OP (b.f2 OP a.f3))
2160 : * are not processable by a parameterized indexscan on a.f1, whereas
2161 : * something like (a.f1 OP (b.f2 OP c.f3)) is.
2162 : *
2163 : * Presently, the executor can only deal with indexquals that have the
2164 : * indexkey on the left, so we can only use clauses that have the indexkey
2165 : * on the right if we can commute the clause to put the key on the left.
2166 : * We handle that by generating an IndexClause with the correctly-commuted
2167 : * opclause as a derived indexqual.
2168 : *
2169 : * If the index has a collation, the clause must have the same collation.
2170 : * For collation-less indexes, we assume it doesn't matter; this is
2171 : * necessary for cases like "hstore ? text", wherein hstore's operators
2172 : * don't care about collation but the clause will get marked with a
2173 : * collation anyway because of the text argument. (This logic is
2174 : * embodied in the macro IndexCollMatchesExprColl.)
2175 : *
2176 : * It is also possible to match RowCompareExpr clauses to indexes (but
2177 : * currently, only btree indexes handle this).
2178 : *
2179 : * It is also possible to match ScalarArrayOpExpr clauses to indexes, when
2180 : * the clause is of the form "indexkey op ANY (arrayconst)".
2181 : *
2182 : * For boolean indexes, it is also possible to match the clause directly
2183 : * to the indexkey; or perhaps the clause is (NOT indexkey).
2184 : *
2185 : * And, last but not least, some operators and functions can be processed
2186 : * to derive (typically lossy) indexquals from a clause that isn't in
2187 : * itself indexable. If we see that any operand of an OpExpr or FuncExpr
2188 : * matches the index key, and the function has a planner support function
2189 : * attached to it, we'll invoke the support function to see if such an
2190 : * indexqual can be built.
2191 : *
2192 : * 'rinfo' is the clause to be tested (as a RestrictInfo node).
2193 : * 'indexcol' is a column number of 'index' (counting from 0).
2194 : * 'index' is the index of interest.
2195 : *
2196 : * Returns an IndexClause if the clause can be used with this index key,
2197 : * or NULL if not.
2198 : *
2199 : * NOTE: returns NULL if clause is an OR or AND clause; it is the
2200 : * responsibility of higher-level routines to cope with those.
2201 : */
2202 : static IndexClause *
2203 1416436 : match_clause_to_indexcol(PlannerInfo *root,
2204 : RestrictInfo *rinfo,
2205 : int indexcol,
2206 : IndexOptInfo *index)
2207 : {
2208 : IndexClause *iclause;
2209 1416436 : Expr *clause = rinfo->clause;
2210 : Oid opfamily;
2211 :
2212 : Assert(indexcol < index->nkeycolumns);
2213 :
2214 : /*
2215 : * Historically this code has coped with NULL clauses. That's probably
2216 : * not possible anymore, but we might as well continue to cope.
2217 : */
2218 1416436 : if (clause == NULL)
2219 0 : return NULL;
2220 :
2221 : /* First check for boolean-index cases. */
2222 1416436 : opfamily = index->opfamily[indexcol];
2223 1416436 : if (IsBooleanOpfamily(opfamily))
2224 : {
2225 194 : iclause = match_boolean_index_clause(root, rinfo, indexcol, index);
2226 194 : if (iclause)
2227 96 : return iclause;
2228 : }
2229 :
2230 : /*
2231 : * Clause must be an opclause, funcclause, ScalarArrayOpExpr, or
2232 : * RowCompareExpr. Or, if the index supports it, we can handle IS
2233 : * NULL/NOT NULL clauses.
2234 : */
2235 1416340 : if (IsA(clause, OpExpr))
2236 : {
2237 1185582 : return match_opclause_to_indexcol(root, rinfo, indexcol, index);
2238 : }
2239 230758 : else if (IsA(clause, FuncExpr))
2240 : {
2241 25812 : return match_funcclause_to_indexcol(root, rinfo, indexcol, index);
2242 : }
2243 204946 : else if (IsA(clause, ScalarArrayOpExpr))
2244 : {
2245 62524 : return match_saopclause_to_indexcol(root, rinfo, indexcol, index);
2246 : }
2247 142422 : else if (IsA(clause, RowCompareExpr))
2248 : {
2249 288 : return match_rowcompare_to_indexcol(root, rinfo, indexcol, index);
2250 : }
2251 142134 : else if (index->amsearchnulls && IsA(clause, NullTest))
2252 : {
2253 15700 : NullTest *nt = (NullTest *) clause;
2254 :
2255 31400 : if (!nt->argisrow &&
2256 15700 : match_index_to_operand((Node *) nt->arg, indexcol, index))
2257 : {
2258 1364 : iclause = makeNode(IndexClause);
2259 1364 : iclause->rinfo = rinfo;
2260 1364 : iclause->indexquals = list_make1(rinfo);
2261 1364 : iclause->lossy = false;
2262 1364 : iclause->indexcol = indexcol;
2263 1364 : iclause->indexcols = NIL;
2264 1364 : return iclause;
2265 : }
2266 : }
2267 :
2268 140770 : return NULL;
2269 : }
2270 :
2271 : /*
2272 : * IsBooleanOpfamily
2273 : * Detect whether an opfamily supports boolean equality as an operator.
2274 : *
2275 : * If the opfamily OID is in the range of built-in objects, we can rely
2276 : * on hard-wired knowledge of which built-in opfamilies support this.
2277 : * For extension opfamilies, there's no choice but to do a catcache lookup.
2278 : */
2279 : static bool
2280 1925356 : IsBooleanOpfamily(Oid opfamily)
2281 : {
2282 1925356 : if (opfamily < FirstNormalObjectId)
2283 1922162 : return IsBuiltinBooleanOpfamily(opfamily);
2284 : else
2285 3194 : return op_in_opfamily(BooleanEqualOperator, opfamily);
2286 : }
2287 :
2288 : /*
2289 : * match_boolean_index_clause
2290 : * Recognize restriction clauses that can be matched to a boolean index.
2291 : *
2292 : * The idea here is that, for an index on a boolean column that supports the
2293 : * BooleanEqualOperator, we can transform a plain reference to the indexkey
2294 : * into "indexkey = true", or "NOT indexkey" into "indexkey = false", etc,
2295 : * so as to make the expression indexable using the index's "=" operator.
2296 : * Since Postgres 8.1, we must do this because constant simplification does
2297 : * the reverse transformation; without this code there'd be no way to use
2298 : * such an index at all.
2299 : *
2300 : * This should be called only when IsBooleanOpfamily() recognizes the
2301 : * index's operator family. We check to see if the clause matches the
2302 : * index's key, and if so, build a suitable IndexClause.
2303 : */
2304 : static IndexClause *
2305 338 : match_boolean_index_clause(PlannerInfo *root,
2306 : RestrictInfo *rinfo,
2307 : int indexcol,
2308 : IndexOptInfo *index)
2309 : {
2310 338 : Node *clause = (Node *) rinfo->clause;
2311 338 : Expr *op = NULL;
2312 :
2313 : /* Direct match? */
2314 338 : if (match_index_to_operand(clause, indexcol, index))
2315 : {
2316 : /* convert to indexkey = TRUE */
2317 94 : op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2318 : (Expr *) clause,
2319 94 : (Expr *) makeBoolConst(true, false),
2320 : InvalidOid, InvalidOid);
2321 : }
2322 : /* NOT clause? */
2323 244 : else if (is_notclause(clause))
2324 : {
2325 74 : Node *arg = (Node *) get_notclausearg((Expr *) clause);
2326 :
2327 74 : if (match_index_to_operand(arg, indexcol, index))
2328 : {
2329 : /* convert to indexkey = FALSE */
2330 74 : op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2331 : (Expr *) arg,
2332 74 : (Expr *) makeBoolConst(false, false),
2333 : InvalidOid, InvalidOid);
2334 : }
2335 : }
2336 :
2337 : /*
2338 : * Since we only consider clauses at top level of WHERE, we can convert
2339 : * indexkey IS TRUE and indexkey IS FALSE to index searches as well. The
2340 : * different meaning for NULL isn't important.
2341 : */
2342 170 : else if (clause && IsA(clause, BooleanTest))
2343 : {
2344 36 : BooleanTest *btest = (BooleanTest *) clause;
2345 36 : Node *arg = (Node *) btest->arg;
2346 :
2347 54 : if (btest->booltesttype == IS_TRUE &&
2348 18 : match_index_to_operand(arg, indexcol, index))
2349 : {
2350 : /* convert to indexkey = TRUE */
2351 18 : op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2352 : (Expr *) arg,
2353 18 : (Expr *) makeBoolConst(true, false),
2354 : InvalidOid, InvalidOid);
2355 : }
2356 36 : else if (btest->booltesttype == IS_FALSE &&
2357 18 : match_index_to_operand(arg, indexcol, index))
2358 : {
2359 : /* convert to indexkey = FALSE */
2360 18 : op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2361 : (Expr *) arg,
2362 18 : (Expr *) makeBoolConst(false, false),
2363 : InvalidOid, InvalidOid);
2364 : }
2365 : }
2366 :
2367 : /*
2368 : * If we successfully made an operator clause from the given qual, we must
2369 : * wrap it in an IndexClause. It's not lossy.
2370 : */
2371 338 : if (op)
2372 : {
2373 204 : IndexClause *iclause = makeNode(IndexClause);
2374 :
2375 204 : iclause->rinfo = rinfo;
2376 204 : iclause->indexquals = list_make1(make_simple_restrictinfo(root, op));
2377 204 : iclause->lossy = false;
2378 204 : iclause->indexcol = indexcol;
2379 204 : iclause->indexcols = NIL;
2380 204 : return iclause;
2381 : }
2382 :
2383 134 : return NULL;
2384 : }
2385 :
2386 : /*
2387 : * match_opclause_to_indexcol()
2388 : * Handles the OpExpr case for match_clause_to_indexcol(),
2389 : * which see for comments.
2390 : */
2391 : static IndexClause *
2392 1185582 : match_opclause_to_indexcol(PlannerInfo *root,
2393 : RestrictInfo *rinfo,
2394 : int indexcol,
2395 : IndexOptInfo *index)
2396 : {
2397 : IndexClause *iclause;
2398 1185582 : OpExpr *clause = (OpExpr *) rinfo->clause;
2399 : Node *leftop,
2400 : *rightop;
2401 : Oid expr_op;
2402 : Oid expr_coll;
2403 : Index index_relid;
2404 : Oid opfamily;
2405 : Oid idxcollation;
2406 :
2407 : /*
2408 : * Only binary operators need apply. (In theory, a planner support
2409 : * function could do something with a unary operator, but it seems
2410 : * unlikely to be worth the cycles to check.)
2411 : */
2412 1185582 : if (list_length(clause->args) != 2)
2413 0 : return NULL;
2414 :
2415 1185582 : leftop = (Node *) linitial(clause->args);
2416 1185582 : rightop = (Node *) lsecond(clause->args);
2417 1185582 : expr_op = clause->opno;
2418 1185582 : expr_coll = clause->inputcollid;
2419 :
2420 1185582 : index_relid = index->rel->relid;
2421 1185582 : opfamily = index->opfamily[indexcol];
2422 1185582 : idxcollation = index->indexcollations[indexcol];
2423 :
2424 : /*
2425 : * Check for clauses of the form: (indexkey operator constant) or
2426 : * (constant operator indexkey). See match_clause_to_indexcol's notes
2427 : * about const-ness.
2428 : *
2429 : * Note that we don't ask the support function about clauses that don't
2430 : * have one of these forms. Again, in principle it might be possible to
2431 : * do something, but it seems unlikely to be worth the cycles to check.
2432 : */
2433 1185582 : if (match_index_to_operand(leftop, indexcol, index) &&
2434 278936 : !bms_is_member(index_relid, rinfo->right_relids) &&
2435 278774 : !contain_volatile_functions(rightop))
2436 : {
2437 551372 : if (IndexCollMatchesExprColl(idxcollation, expr_coll) &&
2438 272598 : op_in_opfamily(expr_op, opfamily))
2439 : {
2440 264926 : iclause = makeNode(IndexClause);
2441 264926 : iclause->rinfo = rinfo;
2442 264926 : iclause->indexquals = list_make1(rinfo);
2443 264926 : iclause->lossy = false;
2444 264926 : iclause->indexcol = indexcol;
2445 264926 : iclause->indexcols = NIL;
2446 264926 : return iclause;
2447 : }
2448 :
2449 : /*
2450 : * If we didn't find a member of the index's opfamily, try the support
2451 : * function for the operator's underlying function.
2452 : */
2453 13848 : set_opfuncid(clause); /* make sure we have opfuncid */
2454 13848 : return get_index_clause_from_support(root,
2455 : rinfo,
2456 : clause->opfuncid,
2457 : 0, /* indexarg on left */
2458 : indexcol,
2459 : index);
2460 : }
2461 :
2462 906808 : if (match_index_to_operand(rightop, indexcol, index) &&
2463 54040 : !bms_is_member(index_relid, rinfo->left_relids) &&
2464 53974 : !contain_volatile_functions(leftop))
2465 : {
2466 53974 : if (IndexCollMatchesExprColl(idxcollation, expr_coll))
2467 : {
2468 53962 : Oid comm_op = get_commutator(expr_op);
2469 :
2470 107924 : if (OidIsValid(comm_op) &&
2471 53962 : op_in_opfamily(comm_op, opfamily))
2472 : {
2473 : RestrictInfo *commrinfo;
2474 :
2475 : /* Build a commuted OpExpr and RestrictInfo */
2476 53498 : commrinfo = commute_restrictinfo(rinfo, comm_op);
2477 :
2478 : /* Make an IndexClause showing that as a derived qual */
2479 53498 : iclause = makeNode(IndexClause);
2480 53498 : iclause->rinfo = rinfo;
2481 53498 : iclause->indexquals = list_make1(commrinfo);
2482 53498 : iclause->lossy = false;
2483 53498 : iclause->indexcol = indexcol;
2484 53498 : iclause->indexcols = NIL;
2485 53498 : return iclause;
2486 : }
2487 : }
2488 :
2489 : /*
2490 : * If we didn't find a member of the index's opfamily, try the support
2491 : * function for the operator's underlying function.
2492 : */
2493 476 : set_opfuncid(clause); /* make sure we have opfuncid */
2494 476 : return get_index_clause_from_support(root,
2495 : rinfo,
2496 : clause->opfuncid,
2497 : 1, /* indexarg on right */
2498 : indexcol,
2499 : index);
2500 : }
2501 :
2502 852834 : return NULL;
2503 : }
2504 :
2505 : /*
2506 : * match_funcclause_to_indexcol()
2507 : * Handles the FuncExpr case for match_clause_to_indexcol(),
2508 : * which see for comments.
2509 : */
2510 : static IndexClause *
2511 25812 : match_funcclause_to_indexcol(PlannerInfo *root,
2512 : RestrictInfo *rinfo,
2513 : int indexcol,
2514 : IndexOptInfo *index)
2515 : {
2516 25812 : FuncExpr *clause = (FuncExpr *) rinfo->clause;
2517 : int indexarg;
2518 : ListCell *lc;
2519 :
2520 : /*
2521 : * We have no built-in intelligence about function clauses, but if there's
2522 : * a planner support function, it might be able to do something. But, to
2523 : * cut down on wasted planning cycles, only call the support function if
2524 : * at least one argument matches the target index column.
2525 : *
2526 : * Note that we don't insist on the other arguments being pseudoconstants;
2527 : * the support function has to check that. This is to allow cases where
2528 : * only some of the other arguments need to be included in the indexqual.
2529 : */
2530 25812 : indexarg = 0;
2531 53254 : foreach(lc, clause->args)
2532 : {
2533 32104 : Node *op = (Node *) lfirst(lc);
2534 :
2535 32104 : if (match_index_to_operand(op, indexcol, index))
2536 : {
2537 4662 : return get_index_clause_from_support(root,
2538 : rinfo,
2539 : clause->funcid,
2540 : indexarg,
2541 : indexcol,
2542 : index);
2543 : }
2544 :
2545 27442 : indexarg++;
2546 : }
2547 :
2548 21150 : return NULL;
2549 : }
2550 :
2551 : /*
2552 : * get_index_clause_from_support()
2553 : * If the function has a planner support function, try to construct
2554 : * an IndexClause using indexquals created by the support function.
2555 : */
2556 : static IndexClause *
2557 18986 : get_index_clause_from_support(PlannerInfo *root,
2558 : RestrictInfo *rinfo,
2559 : Oid funcid,
2560 : int indexarg,
2561 : int indexcol,
2562 : IndexOptInfo *index)
2563 : {
2564 18986 : Oid prosupport = get_func_support(funcid);
2565 : SupportRequestIndexCondition req;
2566 : List *sresult;
2567 :
2568 18986 : if (!OidIsValid(prosupport))
2569 11272 : return NULL;
2570 :
2571 7714 : req.type = T_SupportRequestIndexCondition;
2572 7714 : req.root = root;
2573 7714 : req.funcid = funcid;
2574 7714 : req.node = (Node *) rinfo->clause;
2575 7714 : req.indexarg = indexarg;
2576 7714 : req.index = index;
2577 7714 : req.indexcol = indexcol;
2578 7714 : req.opfamily = index->opfamily[indexcol];
2579 7714 : req.indexcollation = index->indexcollations[indexcol];
2580 :
2581 7714 : req.lossy = true; /* default assumption */
2582 :
2583 : sresult = (List *)
2584 7714 : DatumGetPointer(OidFunctionCall1(prosupport,
2585 : PointerGetDatum(&req)));
2586 :
2587 7714 : if (sresult != NIL)
2588 : {
2589 7222 : IndexClause *iclause = makeNode(IndexClause);
2590 7222 : List *indexquals = NIL;
2591 : ListCell *lc;
2592 :
2593 : /*
2594 : * The support function API says it should just give back bare
2595 : * clauses, so here we must wrap each one in a RestrictInfo.
2596 : */
2597 15726 : foreach(lc, sresult)
2598 : {
2599 8504 : Expr *clause = (Expr *) lfirst(lc);
2600 :
2601 8504 : indexquals = lappend(indexquals,
2602 8504 : make_simple_restrictinfo(root, clause));
2603 : }
2604 :
2605 7222 : iclause->rinfo = rinfo;
2606 7222 : iclause->indexquals = indexquals;
2607 7222 : iclause->lossy = req.lossy;
2608 7222 : iclause->indexcol = indexcol;
2609 7222 : iclause->indexcols = NIL;
2610 :
2611 7222 : return iclause;
2612 : }
2613 :
2614 492 : return NULL;
2615 : }
2616 :
2617 : /*
2618 : * match_saopclause_to_indexcol()
2619 : * Handles the ScalarArrayOpExpr case for match_clause_to_indexcol(),
2620 : * which see for comments.
2621 : */
2622 : static IndexClause *
2623 62524 : match_saopclause_to_indexcol(PlannerInfo *root,
2624 : RestrictInfo *rinfo,
2625 : int indexcol,
2626 : IndexOptInfo *index)
2627 : {
2628 62524 : ScalarArrayOpExpr *saop = (ScalarArrayOpExpr *) rinfo->clause;
2629 : Node *leftop,
2630 : *rightop;
2631 : Relids right_relids;
2632 : Oid expr_op;
2633 : Oid expr_coll;
2634 : Index index_relid;
2635 : Oid opfamily;
2636 : Oid idxcollation;
2637 :
2638 : /* We only accept ANY clauses, not ALL */
2639 62524 : if (!saop->useOr)
2640 8134 : return NULL;
2641 54390 : leftop = (Node *) linitial(saop->args);
2642 54390 : rightop = (Node *) lsecond(saop->args);
2643 54390 : right_relids = pull_varnos(root, rightop);
2644 54390 : expr_op = saop->opno;
2645 54390 : expr_coll = saop->inputcollid;
2646 :
2647 54390 : index_relid = index->rel->relid;
2648 54390 : opfamily = index->opfamily[indexcol];
2649 54390 : idxcollation = index->indexcollations[indexcol];
2650 :
2651 : /*
2652 : * We must have indexkey on the left and a pseudo-constant array argument.
2653 : */
2654 54390 : if (match_index_to_operand(leftop, indexcol, index) &&
2655 5316 : !bms_is_member(index_relid, right_relids) &&
2656 5316 : !contain_volatile_functions(rightop))
2657 : {
2658 10626 : if (IndexCollMatchesExprColl(idxcollation, expr_coll) &&
2659 5310 : op_in_opfamily(expr_op, opfamily))
2660 : {
2661 5298 : IndexClause *iclause = makeNode(IndexClause);
2662 :
2663 5298 : iclause->rinfo = rinfo;
2664 5298 : iclause->indexquals = list_make1(rinfo);
2665 5298 : iclause->lossy = false;
2666 5298 : iclause->indexcol = indexcol;
2667 5298 : iclause->indexcols = NIL;
2668 5298 : return iclause;
2669 : }
2670 :
2671 : /*
2672 : * We do not currently ask support functions about ScalarArrayOpExprs,
2673 : * though in principle we could.
2674 : */
2675 : }
2676 :
2677 49092 : return NULL;
2678 : }
2679 :
2680 : /*
2681 : * match_rowcompare_to_indexcol()
2682 : * Handles the RowCompareExpr case for match_clause_to_indexcol(),
2683 : * which see for comments.
2684 : *
2685 : * In this routine we check whether the first column of the row comparison
2686 : * matches the target index column. This is sufficient to guarantee that some
2687 : * index condition can be constructed from the RowCompareExpr --- the rest
2688 : * is handled by expand_indexqual_rowcompare().
2689 : */
2690 : static IndexClause *
2691 288 : match_rowcompare_to_indexcol(PlannerInfo *root,
2692 : RestrictInfo *rinfo,
2693 : int indexcol,
2694 : IndexOptInfo *index)
2695 : {
2696 288 : RowCompareExpr *clause = (RowCompareExpr *) rinfo->clause;
2697 : Index index_relid;
2698 : Oid opfamily;
2699 : Oid idxcollation;
2700 : Node *leftop,
2701 : *rightop;
2702 : bool var_on_left;
2703 : Oid expr_op;
2704 : Oid expr_coll;
2705 :
2706 : /* Forget it if we're not dealing with a btree index */
2707 288 : if (index->relam != BTREE_AM_OID)
2708 0 : return NULL;
2709 :
2710 288 : index_relid = index->rel->relid;
2711 288 : opfamily = index->opfamily[indexcol];
2712 288 : idxcollation = index->indexcollations[indexcol];
2713 :
2714 : /*
2715 : * We could do the matching on the basis of insisting that the opfamily
2716 : * shown in the RowCompareExpr be the same as the index column's opfamily,
2717 : * but that could fail in the presence of reverse-sort opfamilies: it'd be
2718 : * a matter of chance whether RowCompareExpr had picked the forward or
2719 : * reverse-sort family. So look only at the operator, and match if it is
2720 : * a member of the index's opfamily (after commutation, if the indexkey is
2721 : * on the right). We'll worry later about whether any additional
2722 : * operators are matchable to the index.
2723 : */
2724 288 : leftop = (Node *) linitial(clause->largs);
2725 288 : rightop = (Node *) linitial(clause->rargs);
2726 288 : expr_op = linitial_oid(clause->opnos);
2727 288 : expr_coll = linitial_oid(clause->inputcollids);
2728 :
2729 : /* Collations must match, if relevant */
2730 288 : if (!IndexCollMatchesExprColl(idxcollation, expr_coll))
2731 0 : return NULL;
2732 :
2733 : /*
2734 : * These syntactic tests are the same as in match_opclause_to_indexcol()
2735 : */
2736 288 : if (match_index_to_operand(leftop, indexcol, index) &&
2737 66 : !bms_is_member(index_relid, pull_varnos(root, rightop)) &&
2738 66 : !contain_volatile_functions(rightop))
2739 : {
2740 : /* OK, indexkey is on left */
2741 66 : var_on_left = true;
2742 : }
2743 222 : else if (match_index_to_operand(rightop, indexcol, index) &&
2744 24 : !bms_is_member(index_relid, pull_varnos(root, leftop)) &&
2745 24 : !contain_volatile_functions(leftop))
2746 : {
2747 : /* indexkey is on right, so commute the operator */
2748 24 : expr_op = get_commutator(expr_op);
2749 24 : if (expr_op == InvalidOid)
2750 0 : return NULL;
2751 24 : var_on_left = false;
2752 : }
2753 : else
2754 198 : return NULL;
2755 :
2756 : /* We're good if the operator is the right type of opfamily member */
2757 90 : switch (get_op_opfamily_strategy(expr_op, opfamily))
2758 : {
2759 90 : case BTLessStrategyNumber:
2760 : case BTLessEqualStrategyNumber:
2761 : case BTGreaterEqualStrategyNumber:
2762 : case BTGreaterStrategyNumber:
2763 90 : return expand_indexqual_rowcompare(root,
2764 : rinfo,
2765 : indexcol,
2766 : index,
2767 : expr_op,
2768 : var_on_left);
2769 : }
2770 :
2771 0 : return NULL;
2772 : }
2773 :
2774 : /*
2775 : * expand_indexqual_rowcompare --- expand a single indexqual condition
2776 : * that is a RowCompareExpr
2777 : *
2778 : * It's already known that the first column of the row comparison matches
2779 : * the specified column of the index. We can use additional columns of the
2780 : * row comparison as index qualifications, so long as they match the index
2781 : * in the "same direction", ie, the indexkeys are all on the same side of the
2782 : * clause and the operators are all the same-type members of the opfamilies.
2783 : *
2784 : * If all the columns of the RowCompareExpr match in this way, we just use it
2785 : * as-is, except for possibly commuting it to put the indexkeys on the left.
2786 : *
2787 : * Otherwise, we build a shortened RowCompareExpr (if more than one
2788 : * column matches) or a simple OpExpr (if the first-column match is all
2789 : * there is). In these cases the modified clause is always "<=" or ">="
2790 : * even when the original was "<" or ">" --- this is necessary to match all
2791 : * the rows that could match the original. (We are building a lossy version
2792 : * of the row comparison when we do this, so we set lossy = true.)
2793 : *
2794 : * Note: this is really just the last half of match_rowcompare_to_indexcol,
2795 : * but we split it out for comprehensibility.
2796 : */
2797 : static IndexClause *
2798 90 : expand_indexqual_rowcompare(PlannerInfo *root,
2799 : RestrictInfo *rinfo,
2800 : int indexcol,
2801 : IndexOptInfo *index,
2802 : Oid expr_op,
2803 : bool var_on_left)
2804 : {
2805 90 : IndexClause *iclause = makeNode(IndexClause);
2806 90 : RowCompareExpr *clause = (RowCompareExpr *) rinfo->clause;
2807 : int op_strategy;
2808 : Oid op_lefttype;
2809 : Oid op_righttype;
2810 : int matching_cols;
2811 : List *expr_ops;
2812 : List *opfamilies;
2813 : List *lefttypes;
2814 : List *righttypes;
2815 : List *new_ops;
2816 : List *var_args;
2817 : List *non_var_args;
2818 :
2819 90 : iclause->rinfo = rinfo;
2820 90 : iclause->indexcol = indexcol;
2821 :
2822 90 : if (var_on_left)
2823 : {
2824 66 : var_args = clause->largs;
2825 66 : non_var_args = clause->rargs;
2826 : }
2827 : else
2828 : {
2829 24 : var_args = clause->rargs;
2830 24 : non_var_args = clause->largs;
2831 : }
2832 :
2833 90 : get_op_opfamily_properties(expr_op, index->opfamily[indexcol], false,
2834 : &op_strategy,
2835 : &op_lefttype,
2836 : &op_righttype);
2837 :
2838 : /* Initialize returned list of which index columns are used */
2839 90 : iclause->indexcols = list_make1_int(indexcol);
2840 :
2841 : /* Build lists of ops, opfamilies and operator datatypes in case needed */
2842 90 : expr_ops = list_make1_oid(expr_op);
2843 90 : opfamilies = list_make1_oid(index->opfamily[indexcol]);
2844 90 : lefttypes = list_make1_oid(op_lefttype);
2845 90 : righttypes = list_make1_oid(op_righttype);
2846 :
2847 : /*
2848 : * See how many of the remaining columns match some index column in the
2849 : * same way. As in match_clause_to_indexcol(), the "other" side of any
2850 : * potential index condition is OK as long as it doesn't use Vars from the
2851 : * indexed relation.
2852 : */
2853 90 : matching_cols = 1;
2854 :
2855 162 : while (matching_cols < list_length(var_args))
2856 : {
2857 126 : Node *varop = (Node *) list_nth(var_args, matching_cols);
2858 126 : Node *constop = (Node *) list_nth(non_var_args, matching_cols);
2859 : int i;
2860 :
2861 126 : expr_op = list_nth_oid(clause->opnos, matching_cols);
2862 126 : if (!var_on_left)
2863 : {
2864 : /* indexkey is on right, so commute the operator */
2865 24 : expr_op = get_commutator(expr_op);
2866 24 : if (expr_op == InvalidOid)
2867 0 : break; /* operator is not usable */
2868 : }
2869 126 : if (bms_is_member(index->rel->relid, pull_varnos(root, constop)))
2870 0 : break; /* no good, Var on wrong side */
2871 126 : if (contain_volatile_functions(constop))
2872 0 : break; /* no good, volatile comparison value */
2873 :
2874 : /*
2875 : * The Var side can match any key column of the index.
2876 : */
2877 300 : for (i = 0; i < index->nkeycolumns; i++)
2878 : {
2879 246 : if (match_index_to_operand(varop, i, index) &&
2880 72 : get_op_opfamily_strategy(expr_op,
2881 72 : index->opfamily[i]) == op_strategy &&
2882 72 : IndexCollMatchesExprColl(index->indexcollations[i],
2883 : list_nth_oid(clause->inputcollids,
2884 : matching_cols)))
2885 : break;
2886 : }
2887 126 : if (i >= index->nkeycolumns)
2888 54 : break; /* no match found */
2889 :
2890 : /* Add column number to returned list */
2891 72 : iclause->indexcols = lappend_int(iclause->indexcols, i);
2892 :
2893 : /* Add operator info to lists */
2894 72 : get_op_opfamily_properties(expr_op, index->opfamily[i], false,
2895 : &op_strategy,
2896 : &op_lefttype,
2897 : &op_righttype);
2898 72 : expr_ops = lappend_oid(expr_ops, expr_op);
2899 72 : opfamilies = lappend_oid(opfamilies, index->opfamily[i]);
2900 72 : lefttypes = lappend_oid(lefttypes, op_lefttype);
2901 72 : righttypes = lappend_oid(righttypes, op_righttype);
2902 :
2903 : /* This column matches, keep scanning */
2904 72 : matching_cols++;
2905 : }
2906 :
2907 : /* Result is non-lossy if all columns are usable as index quals */
2908 90 : iclause->lossy = (matching_cols != list_length(clause->opnos));
2909 :
2910 : /*
2911 : * We can use rinfo->clause as-is if we have var on left and it's all
2912 : * usable as index quals.
2913 : */
2914 90 : if (var_on_left && !iclause->lossy)
2915 24 : iclause->indexquals = list_make1(rinfo);
2916 : else
2917 : {
2918 : /*
2919 : * We have to generate a modified rowcompare (possibly just one
2920 : * OpExpr). The painful part of this is changing < to <= or > to >=,
2921 : * so deal with that first.
2922 : */
2923 66 : if (!iclause->lossy)
2924 : {
2925 : /* very easy, just use the commuted operators */
2926 12 : new_ops = expr_ops;
2927 : }
2928 54 : else if (op_strategy == BTLessEqualStrategyNumber ||
2929 54 : op_strategy == BTGreaterEqualStrategyNumber)
2930 : {
2931 : /* easy, just use the same (possibly commuted) operators */
2932 0 : new_ops = list_truncate(expr_ops, matching_cols);
2933 : }
2934 : else
2935 : {
2936 : ListCell *opfamilies_cell;
2937 : ListCell *lefttypes_cell;
2938 : ListCell *righttypes_cell;
2939 :
2940 54 : if (op_strategy == BTLessStrategyNumber)
2941 30 : op_strategy = BTLessEqualStrategyNumber;
2942 24 : else if (op_strategy == BTGreaterStrategyNumber)
2943 24 : op_strategy = BTGreaterEqualStrategyNumber;
2944 : else
2945 0 : elog(ERROR, "unexpected strategy number %d", op_strategy);
2946 54 : new_ops = NIL;
2947 144 : forthree(opfamilies_cell, opfamilies,
2948 : lefttypes_cell, lefttypes,
2949 : righttypes_cell, righttypes)
2950 : {
2951 90 : Oid opfam = lfirst_oid(opfamilies_cell);
2952 90 : Oid lefttype = lfirst_oid(lefttypes_cell);
2953 90 : Oid righttype = lfirst_oid(righttypes_cell);
2954 :
2955 90 : expr_op = get_opfamily_member(opfam, lefttype, righttype,
2956 : op_strategy);
2957 90 : if (!OidIsValid(expr_op)) /* should not happen */
2958 0 : elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
2959 : op_strategy, lefttype, righttype, opfam);
2960 90 : new_ops = lappend_oid(new_ops, expr_op);
2961 : }
2962 : }
2963 :
2964 : /* If we have more than one matching col, create a subset rowcompare */
2965 66 : if (matching_cols > 1)
2966 : {
2967 48 : RowCompareExpr *rc = makeNode(RowCompareExpr);
2968 :
2969 48 : rc->rctype = (RowCompareType) op_strategy;
2970 48 : rc->opnos = new_ops;
2971 48 : rc->opfamilies = list_copy_head(clause->opfamilies,
2972 : matching_cols);
2973 48 : rc->inputcollids = list_copy_head(clause->inputcollids,
2974 : matching_cols);
2975 48 : rc->largs = list_copy_head(var_args, matching_cols);
2976 48 : rc->rargs = list_copy_head(non_var_args, matching_cols);
2977 48 : iclause->indexquals = list_make1(make_simple_restrictinfo(root,
2978 : (Expr *) rc));
2979 : }
2980 : else
2981 : {
2982 : Expr *op;
2983 :
2984 : /* We don't report an index column list in this case */
2985 18 : iclause->indexcols = NIL;
2986 :
2987 18 : op = make_opclause(linitial_oid(new_ops), BOOLOID, false,
2988 18 : copyObject(linitial(var_args)),
2989 18 : copyObject(linitial(non_var_args)),
2990 : InvalidOid,
2991 18 : linitial_oid(clause->inputcollids));
2992 18 : iclause->indexquals = list_make1(make_simple_restrictinfo(root, op));
2993 : }
2994 : }
2995 :
2996 90 : return iclause;
2997 : }
2998 :
2999 :
3000 : /****************************************************************************
3001 : * ---- ROUTINES TO CHECK ORDERING OPERATORS ----
3002 : ****************************************************************************/
3003 :
3004 : /*
3005 : * match_pathkeys_to_index
3006 : * For the given 'index' and 'pathkeys', output a list of suitable ORDER
3007 : * BY expressions, each of the form "indexedcol operator pseudoconstant",
3008 : * along with an integer list of the index column numbers (zero based)
3009 : * that each clause would be used with.
3010 : *
3011 : * This attempts to find an ORDER BY and index column number for all items in
3012 : * the pathkey list, however, if we're unable to match any given pathkey to an
3013 : * index column, we return just the ones matched by the function so far. This
3014 : * allows callers who are interested in partial matches to get them. Callers
3015 : * can determine a partial match vs a full match by checking the outputted
3016 : * list lengths. A full match will have one item in the output lists for each
3017 : * item in the given 'pathkeys' list.
3018 : */
3019 : static void
3020 862 : match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys,
3021 : List **orderby_clauses_p,
3022 : List **clause_columns_p)
3023 : {
3024 : ListCell *lc1;
3025 :
3026 862 : *orderby_clauses_p = NIL; /* set default results */
3027 862 : *clause_columns_p = NIL;
3028 :
3029 : /* Only indexes with the amcanorderbyop property are interesting here */
3030 862 : if (!index->amcanorderbyop)
3031 0 : return;
3032 :
3033 1336 : foreach(lc1, pathkeys)
3034 : {
3035 862 : PathKey *pathkey = (PathKey *) lfirst(lc1);
3036 862 : bool found = false;
3037 : ListCell *lc2;
3038 :
3039 :
3040 : /* Pathkey must request default sort order for the target opfamily */
3041 862 : if (pathkey->pk_strategy != BTLessStrategyNumber ||
3042 828 : pathkey->pk_nulls_first)
3043 388 : return;
3044 :
3045 : /* If eclass is volatile, no hope of using an indexscan */
3046 828 : if (pathkey->pk_eclass->ec_has_volatile)
3047 0 : return;
3048 :
3049 : /*
3050 : * Try to match eclass member expression(s) to index. Note that child
3051 : * EC members are considered, but only when they belong to the target
3052 : * relation. (Unlike regular members, the same expression could be a
3053 : * child member of more than one EC. Therefore, the same index could
3054 : * be considered to match more than one pathkey list, which is OK
3055 : * here. See also get_eclass_for_sort_expr.)
3056 : */
3057 1246 : foreach(lc2, pathkey->pk_eclass->ec_members)
3058 : {
3059 892 : EquivalenceMember *member = (EquivalenceMember *) lfirst(lc2);
3060 : int indexcol;
3061 :
3062 : /* No possibility of match if it references other relations */
3063 892 : if (!bms_equal(member->em_relids, index->rel->relids))
3064 64 : continue;
3065 :
3066 : /*
3067 : * We allow any column of the index to match each pathkey; they
3068 : * don't have to match left-to-right as you might expect. This is
3069 : * correct for GiST, and it doesn't matter for SP-GiST because
3070 : * that doesn't handle multiple columns anyway, and no other
3071 : * existing AMs support amcanorderbyop. We might need different
3072 : * logic in future for other implementations.
3073 : */
3074 1252 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
3075 : {
3076 : Expr *expr;
3077 :
3078 898 : expr = match_clause_to_ordering_op(index,
3079 : indexcol,
3080 : member->em_expr,
3081 : pathkey->pk_opfamily);
3082 898 : if (expr)
3083 : {
3084 474 : *orderby_clauses_p = lappend(*orderby_clauses_p, expr);
3085 474 : *clause_columns_p = lappend_int(*clause_columns_p, indexcol);
3086 474 : found = true;
3087 474 : break;
3088 : }
3089 : }
3090 :
3091 828 : if (found) /* don't want to look at remaining members */
3092 474 : break;
3093 : }
3094 :
3095 : /*
3096 : * Return the matches found so far when this pathkey couldn't be
3097 : * matched to the index.
3098 : */
3099 828 : if (!found)
3100 354 : return;
3101 : }
3102 : }
3103 :
3104 : /*
3105 : * match_clause_to_ordering_op
3106 : * Determines whether an ordering operator expression matches an
3107 : * index column.
3108 : *
3109 : * This is similar to, but simpler than, match_clause_to_indexcol.
3110 : * We only care about simple OpExpr cases. The input is a bare
3111 : * expression that is being ordered by, which must be of the form
3112 : * (indexkey op const) or (const op indexkey) where op is an ordering
3113 : * operator for the column's opfamily.
3114 : *
3115 : * 'index' is the index of interest.
3116 : * 'indexcol' is a column number of 'index' (counting from 0).
3117 : * 'clause' is the ordering expression to be tested.
3118 : * 'pk_opfamily' is the btree opfamily describing the required sort order.
3119 : *
3120 : * Note that we currently do not consider the collation of the ordering
3121 : * operator's result. In practical cases the result type will be numeric
3122 : * and thus have no collation, and it's not very clear what to match to
3123 : * if it did have a collation. The index's collation should match the
3124 : * ordering operator's input collation, not its result.
3125 : *
3126 : * If successful, return 'clause' as-is if the indexkey is on the left,
3127 : * otherwise a commuted copy of 'clause'. If no match, return NULL.
3128 : */
3129 : static Expr *
3130 898 : match_clause_to_ordering_op(IndexOptInfo *index,
3131 : int indexcol,
3132 : Expr *clause,
3133 : Oid pk_opfamily)
3134 : {
3135 : Oid opfamily;
3136 : Oid idxcollation;
3137 : Node *leftop,
3138 : *rightop;
3139 : Oid expr_op;
3140 : Oid expr_coll;
3141 : Oid sortfamily;
3142 : bool commuted;
3143 :
3144 : Assert(indexcol < index->nkeycolumns);
3145 :
3146 898 : opfamily = index->opfamily[indexcol];
3147 898 : idxcollation = index->indexcollations[indexcol];
3148 :
3149 : /*
3150 : * Clause must be a binary opclause.
3151 : */
3152 898 : if (!is_opclause(clause))
3153 424 : return NULL;
3154 474 : leftop = get_leftop(clause);
3155 474 : rightop = get_rightop(clause);
3156 474 : if (!leftop || !rightop)
3157 0 : return NULL;
3158 474 : expr_op = ((OpExpr *) clause)->opno;
3159 474 : expr_coll = ((OpExpr *) clause)->inputcollid;
3160 :
3161 : /*
3162 : * We can forget the whole thing right away if wrong collation.
3163 : */
3164 474 : if (!IndexCollMatchesExprColl(idxcollation, expr_coll))
3165 0 : return NULL;
3166 :
3167 : /*
3168 : * Check for clauses of the form: (indexkey operator constant) or
3169 : * (constant operator indexkey).
3170 : */
3171 474 : if (match_index_to_operand(leftop, indexcol, index) &&
3172 450 : !contain_var_clause(rightop) &&
3173 450 : !contain_volatile_functions(rightop))
3174 : {
3175 450 : commuted = false;
3176 : }
3177 24 : else if (match_index_to_operand(rightop, indexcol, index) &&
3178 24 : !contain_var_clause(leftop) &&
3179 24 : !contain_volatile_functions(leftop))
3180 : {
3181 : /* Might match, but we need a commuted operator */
3182 24 : expr_op = get_commutator(expr_op);
3183 24 : if (expr_op == InvalidOid)
3184 0 : return NULL;
3185 24 : commuted = true;
3186 : }
3187 : else
3188 0 : return NULL;
3189 :
3190 : /*
3191 : * Is the (commuted) operator an ordering operator for the opfamily? And
3192 : * if so, does it yield the right sorting semantics?
3193 : */
3194 474 : sortfamily = get_op_opfamily_sortfamily(expr_op, opfamily);
3195 474 : if (sortfamily != pk_opfamily)
3196 0 : return NULL;
3197 :
3198 : /* We have a match. Return clause or a commuted version thereof. */
3199 474 : if (commuted)
3200 : {
3201 24 : OpExpr *newclause = makeNode(OpExpr);
3202 :
3203 : /* flat-copy all the fields of clause */
3204 24 : memcpy(newclause, clause, sizeof(OpExpr));
3205 :
3206 : /* commute it */
3207 24 : newclause->opno = expr_op;
3208 24 : newclause->opfuncid = InvalidOid;
3209 24 : newclause->args = list_make2(rightop, leftop);
3210 :
3211 24 : clause = (Expr *) newclause;
3212 : }
3213 :
3214 474 : return clause;
3215 : }
3216 :
3217 :
3218 : /****************************************************************************
3219 : * ---- ROUTINES TO DO PARTIAL INDEX PREDICATE TESTS ----
3220 : ****************************************************************************/
3221 :
3222 : /*
3223 : * check_index_predicates
3224 : * Set the predicate-derived IndexOptInfo fields for each index
3225 : * of the specified relation.
3226 : *
3227 : * predOK is set true if the index is partial and its predicate is satisfied
3228 : * for this query, ie the query's WHERE clauses imply the predicate.
3229 : *
3230 : * indrestrictinfo is set to the relation's baserestrictinfo list less any
3231 : * conditions that are implied by the index's predicate. (Obviously, for a
3232 : * non-partial index, this is the same as baserestrictinfo.) Such conditions
3233 : * can be dropped from the plan when using the index, in certain cases.
3234 : *
3235 : * At one time it was possible for this to get re-run after adding more
3236 : * restrictions to the rel, thus possibly letting us prove more indexes OK.
3237 : * That doesn't happen any more (at least not in the core code's usage),
3238 : * but this code still supports it in case extensions want to mess with the
3239 : * baserestrictinfo list. We assume that adding more restrictions can't make
3240 : * an index not predOK. We must recompute indrestrictinfo each time, though,
3241 : * to make sure any newly-added restrictions get into it if needed.
3242 : */
3243 : void
3244 348926 : check_index_predicates(PlannerInfo *root, RelOptInfo *rel)
3245 : {
3246 : List *clauselist;
3247 : bool have_partial;
3248 : bool is_target_rel;
3249 : Relids otherrels;
3250 : ListCell *lc;
3251 :
3252 : /* Indexes are available only on base or "other" member relations. */
3253 : Assert(IS_SIMPLE_REL(rel));
3254 :
3255 : /*
3256 : * Initialize the indrestrictinfo lists to be identical to
3257 : * baserestrictinfo, and check whether there are any partial indexes. If
3258 : * not, this is all we need to do.
3259 : */
3260 348926 : have_partial = false;
3261 950356 : foreach(lc, rel->indexlist)
3262 : {
3263 601430 : IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
3264 :
3265 601430 : index->indrestrictinfo = rel->baserestrictinfo;
3266 601430 : if (index->indpred)
3267 966 : have_partial = true;
3268 : }
3269 348926 : if (!have_partial)
3270 348278 : return;
3271 :
3272 : /*
3273 : * Construct a list of clauses that we can assume true for the purpose of
3274 : * proving the index(es) usable. Restriction clauses for the rel are
3275 : * always usable, and so are any join clauses that are "movable to" this
3276 : * rel. Also, we can consider any EC-derivable join clauses (which must
3277 : * be "movable to" this rel, by definition).
3278 : */
3279 648 : clauselist = list_copy(rel->baserestrictinfo);
3280 :
3281 : /* Scan the rel's join clauses */
3282 648 : foreach(lc, rel->joininfo)
3283 : {
3284 0 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
3285 :
3286 : /* Check if clause can be moved to this rel */
3287 0 : if (!join_clause_is_movable_to(rinfo, rel))
3288 0 : continue;
3289 :
3290 0 : clauselist = lappend(clauselist, rinfo);
3291 : }
3292 :
3293 : /*
3294 : * Add on any equivalence-derivable join clauses. Computing the correct
3295 : * relid sets for generate_join_implied_equalities is slightly tricky
3296 : * because the rel could be a child rel rather than a true baserel, and in
3297 : * that case we must subtract its parents' relid(s) from all_query_rels.
3298 : * Additionally, we mustn't consider clauses that are only computable
3299 : * after outer joins that can null the rel.
3300 : */
3301 648 : if (rel->reloptkind == RELOPT_OTHER_MEMBER_REL)
3302 72 : otherrels = bms_difference(root->all_query_rels,
3303 72 : find_childrel_parents(root, rel));
3304 : else
3305 576 : otherrels = bms_difference(root->all_query_rels, rel->relids);
3306 648 : otherrels = bms_del_members(otherrels, rel->nulling_relids);
3307 :
3308 648 : if (!bms_is_empty(otherrels))
3309 : clauselist =
3310 88 : list_concat(clauselist,
3311 88 : generate_join_implied_equalities(root,
3312 88 : bms_union(rel->relids,
3313 : otherrels),
3314 : otherrels,
3315 : rel,
3316 : NULL));
3317 :
3318 : /*
3319 : * Normally we remove quals that are implied by a partial index's
3320 : * predicate from indrestrictinfo, indicating that they need not be
3321 : * checked explicitly by an indexscan plan using this index. However, if
3322 : * the rel is a target relation of UPDATE/DELETE/MERGE/SELECT FOR UPDATE,
3323 : * we cannot remove such quals from the plan, because they need to be in
3324 : * the plan so that they will be properly rechecked by EvalPlanQual
3325 : * testing. Some day we might want to remove such quals from the main
3326 : * plan anyway and pass them through to EvalPlanQual via a side channel;
3327 : * but for now, we just don't remove implied quals at all for target
3328 : * relations.
3329 : */
3330 1184 : is_target_rel = (bms_is_member(rel->relid, root->all_result_relids) ||
3331 536 : get_plan_rowmark(root->rowMarks, rel->relid) != NULL);
3332 :
3333 : /*
3334 : * Now try to prove each index predicate true, and compute the
3335 : * indrestrictinfo lists for partial indexes. Note that we compute the
3336 : * indrestrictinfo list even for non-predOK indexes; this might seem
3337 : * wasteful, but we may be able to use such indexes in OR clauses, cf
3338 : * generate_bitmap_or_paths().
3339 : */
3340 1994 : foreach(lc, rel->indexlist)
3341 : {
3342 1346 : IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
3343 : ListCell *lcr;
3344 :
3345 1346 : if (index->indpred == NIL)
3346 380 : continue; /* ignore non-partial indexes here */
3347 :
3348 966 : if (!index->predOK) /* don't repeat work if already proven OK */
3349 966 : index->predOK = predicate_implied_by(index->indpred, clauselist,
3350 : false);
3351 :
3352 : /* If rel is an update target, leave indrestrictinfo as set above */
3353 966 : if (is_target_rel)
3354 172 : continue;
3355 :
3356 : /* Else compute indrestrictinfo as the non-implied quals */
3357 794 : index->indrestrictinfo = NIL;
3358 1872 : foreach(lcr, rel->baserestrictinfo)
3359 : {
3360 1078 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lcr);
3361 :
3362 : /* predicate_implied_by() assumes first arg is immutable */
3363 1078 : if (contain_mutable_functions((Node *) rinfo->clause) ||
3364 1078 : !predicate_implied_by(list_make1(rinfo->clause),
3365 : index->indpred, false))
3366 770 : index->indrestrictinfo = lappend(index->indrestrictinfo, rinfo);
3367 : }
3368 : }
3369 : }
3370 :
3371 : /****************************************************************************
3372 : * ---- ROUTINES TO CHECK EXTERNALLY-VISIBLE CONDITIONS ----
3373 : ****************************************************************************/
3374 :
3375 : /*
3376 : * ec_member_matches_indexcol
3377 : * Test whether an EquivalenceClass member matches an index column.
3378 : *
3379 : * This is a callback for use by generate_implied_equalities_for_column.
3380 : */
3381 : static bool
3382 303546 : ec_member_matches_indexcol(PlannerInfo *root, RelOptInfo *rel,
3383 : EquivalenceClass *ec, EquivalenceMember *em,
3384 : void *arg)
3385 : {
3386 303546 : IndexOptInfo *index = ((ec_member_matches_arg *) arg)->index;
3387 303546 : int indexcol = ((ec_member_matches_arg *) arg)->indexcol;
3388 : Oid curFamily;
3389 : Oid curCollation;
3390 :
3391 : Assert(indexcol < index->nkeycolumns);
3392 :
3393 303546 : curFamily = index->opfamily[indexcol];
3394 303546 : curCollation = index->indexcollations[indexcol];
3395 :
3396 : /*
3397 : * If it's a btree index, we can reject it if its opfamily isn't
3398 : * compatible with the EC, since no clause generated from the EC could be
3399 : * used with the index. For non-btree indexes, we can't easily tell
3400 : * whether clauses generated from the EC could be used with the index, so
3401 : * don't check the opfamily. This might mean we return "true" for a
3402 : * useless EC, so we have to recheck the results of
3403 : * generate_implied_equalities_for_column; see
3404 : * match_eclass_clauses_to_index.
3405 : */
3406 303546 : if (index->relam == BTREE_AM_OID &&
3407 303504 : !list_member_oid(ec->ec_opfamilies, curFamily))
3408 92438 : return false;
3409 :
3410 : /* We insist on collation match for all index types, though */
3411 211108 : if (!IndexCollMatchesExprColl(curCollation, ec->ec_collation))
3412 14 : return false;
3413 :
3414 211094 : return match_index_to_operand((Node *) em->em_expr, indexcol, index);
3415 : }
3416 :
3417 : /*
3418 : * relation_has_unique_index_for
3419 : * Determine whether the relation provably has at most one row satisfying
3420 : * a set of equality conditions, because the conditions constrain all
3421 : * columns of some unique index.
3422 : *
3423 : * The conditions can be represented in either or both of two ways:
3424 : * 1. A list of RestrictInfo nodes, where the caller has already determined
3425 : * that each condition is a mergejoinable equality with an expression in
3426 : * this relation on one side, and an expression not involving this relation
3427 : * on the other. The transient outer_is_left flag is used to identify which
3428 : * side we should look at: left side if outer_is_left is false, right side
3429 : * if it is true.
3430 : * 2. A list of expressions in this relation, and a corresponding list of
3431 : * equality operators. The caller must have already checked that the operators
3432 : * represent equality. (Note: the operators could be cross-type; the
3433 : * expressions should correspond to their RHS inputs.)
3434 : *
3435 : * The caller need only supply equality conditions arising from joins;
3436 : * this routine automatically adds in any usable baserestrictinfo clauses.
3437 : * (Note that the passed-in restrictlist will be destructively modified!)
3438 : */
3439 : bool
3440 886 : relation_has_unique_index_for(PlannerInfo *root, RelOptInfo *rel,
3441 : List *restrictlist,
3442 : List *exprlist, List *oprlist)
3443 : {
3444 886 : return relation_has_unique_index_ext(root, rel, restrictlist,
3445 : exprlist, oprlist, NULL);
3446 : }
3447 :
3448 : /*
3449 : * relation_has_unique_index_ext
3450 : * Same as relation_has_unique_index_for(), but supports extra_clauses
3451 : * parameter. If extra_clauses isn't NULL, return baserestrictinfo clauses
3452 : * which were used to derive uniqueness.
3453 : */
3454 : bool
3455 168032 : relation_has_unique_index_ext(PlannerInfo *root, RelOptInfo *rel,
3456 : List *restrictlist,
3457 : List *exprlist, List *oprlist,
3458 : List **extra_clauses)
3459 : {
3460 : ListCell *ic;
3461 :
3462 : Assert(list_length(exprlist) == list_length(oprlist));
3463 :
3464 : /* Short-circuit if no indexes... */
3465 168032 : if (rel->indexlist == NIL)
3466 440 : return false;
3467 :
3468 : /*
3469 : * Examine the rel's restriction clauses for usable var = const clauses
3470 : * that we can add to the restrictlist.
3471 : */
3472 278396 : foreach(ic, rel->baserestrictinfo)
3473 : {
3474 110804 : RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(ic);
3475 :
3476 : /*
3477 : * Note: can_join won't be set for a restriction clause, but
3478 : * mergeopfamilies will be if it has a mergejoinable operator and
3479 : * doesn't contain volatile functions.
3480 : */
3481 110804 : if (restrictinfo->mergeopfamilies == NIL)
3482 50256 : continue; /* not mergejoinable */
3483 :
3484 : /*
3485 : * The clause certainly doesn't refer to anything but the given rel.
3486 : * If either side is pseudoconstant then we can use it.
3487 : */
3488 60548 : if (bms_is_empty(restrictinfo->left_relids))
3489 : {
3490 : /* righthand side is inner */
3491 40 : restrictinfo->outer_is_left = true;
3492 : }
3493 60508 : else if (bms_is_empty(restrictinfo->right_relids))
3494 : {
3495 : /* lefthand side is inner */
3496 60382 : restrictinfo->outer_is_left = false;
3497 : }
3498 : else
3499 126 : continue;
3500 :
3501 : /* OK, add to list */
3502 60422 : restrictlist = lappend(restrictlist, restrictinfo);
3503 : }
3504 :
3505 : /* Short-circuit the easy case */
3506 167592 : if (restrictlist == NIL && exprlist == NIL)
3507 1306 : return false;
3508 :
3509 : /* Examine each index of the relation ... */
3510 433360 : foreach(ic, rel->indexlist)
3511 : {
3512 369166 : IndexOptInfo *ind = (IndexOptInfo *) lfirst(ic);
3513 : int c;
3514 369166 : List *exprs = NIL;
3515 :
3516 : /*
3517 : * If the index is not unique, or not immediately enforced, or if it's
3518 : * a partial index, it's useless here. We're unable to make use of
3519 : * predOK partial unique indexes due to the fact that
3520 : * check_index_predicates() also makes use of join predicates to
3521 : * determine if the partial index is usable. Here we need proofs that
3522 : * hold true before any joins are evaluated.
3523 : */
3524 369166 : if (!ind->unique || !ind->immediate || ind->indpred != NIL)
3525 109044 : continue;
3526 :
3527 : /*
3528 : * Try to find each index column in the lists of conditions. This is
3529 : * O(N^2) or worse, but we expect all the lists to be short.
3530 : */
3531 420750 : for (c = 0; c < ind->nkeycolumns; c++)
3532 : {
3533 318658 : bool matched = false;
3534 : ListCell *lc;
3535 : ListCell *lc2;
3536 :
3537 598376 : foreach(lc, restrictlist)
3538 : {
3539 440340 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
3540 : Node *rexpr;
3541 :
3542 : /*
3543 : * The condition's equality operator must be a member of the
3544 : * index opfamily, else it is not asserting the right kind of
3545 : * equality behavior for this index. We check this first
3546 : * since it's probably cheaper than match_index_to_operand().
3547 : */
3548 440340 : if (!list_member_oid(rinfo->mergeopfamilies, ind->opfamily[c]))
3549 132020 : continue;
3550 :
3551 : /*
3552 : * XXX at some point we may need to check collations here too.
3553 : * For the moment we assume all collations reduce to the same
3554 : * notion of equality.
3555 : */
3556 :
3557 : /* OK, see if the condition operand matches the index key */
3558 308320 : if (rinfo->outer_is_left)
3559 136732 : rexpr = get_rightop(rinfo->clause);
3560 : else
3561 171588 : rexpr = get_leftop(rinfo->clause);
3562 :
3563 308320 : if (match_index_to_operand(rexpr, c, ind))
3564 : {
3565 160622 : matched = true; /* column is unique */
3566 :
3567 160622 : if (bms_membership(rinfo->clause_relids) == BMS_SINGLETON)
3568 : {
3569 : MemoryContext oldMemCtx =
3570 43084 : MemoryContextSwitchTo(root->planner_cxt);
3571 :
3572 : /*
3573 : * Add filter clause into a list allowing caller to
3574 : * know if uniqueness have made not only by join
3575 : * clauses.
3576 : */
3577 : Assert(bms_is_empty(rinfo->left_relids) ||
3578 : bms_is_empty(rinfo->right_relids));
3579 43084 : if (extra_clauses)
3580 238 : exprs = lappend(exprs, rinfo);
3581 43084 : MemoryContextSwitchTo(oldMemCtx);
3582 : }
3583 :
3584 160622 : break;
3585 : }
3586 : }
3587 :
3588 318658 : if (matched)
3589 160622 : continue;
3590 :
3591 158194 : forboth(lc, exprlist, lc2, oprlist)
3592 : {
3593 164 : Node *expr = (Node *) lfirst(lc);
3594 164 : Oid opr = lfirst_oid(lc2);
3595 :
3596 : /* See if the expression matches the index key */
3597 164 : if (!match_index_to_operand(expr, c, ind))
3598 158 : continue;
3599 :
3600 : /*
3601 : * The equality operator must be a member of the index
3602 : * opfamily, else it is not asserting the right kind of
3603 : * equality behavior for this index. We assume the caller
3604 : * determined it is an equality operator, so we don't need to
3605 : * check any more tightly than this.
3606 : */
3607 6 : if (!op_in_opfamily(opr, ind->opfamily[c]))
3608 0 : continue;
3609 :
3610 : /*
3611 : * XXX at some point we may need to check collations here too.
3612 : * For the moment we assume all collations reduce to the same
3613 : * notion of equality.
3614 : */
3615 :
3616 6 : matched = true; /* column is unique */
3617 6 : break;
3618 : }
3619 :
3620 158036 : if (!matched)
3621 158030 : break; /* no match; this index doesn't help us */
3622 : }
3623 :
3624 : /* Matched all key columns of this index? */
3625 260122 : if (c == ind->nkeycolumns)
3626 : {
3627 102092 : if (extra_clauses)
3628 694 : *extra_clauses = exprs;
3629 102092 : return true;
3630 : }
3631 : }
3632 :
3633 64194 : return false;
3634 : }
3635 :
3636 : /*
3637 : * indexcol_is_bool_constant_for_query
3638 : *
3639 : * If an index column is constrained to have a constant value by the query's
3640 : * WHERE conditions, then it's irrelevant for sort-order considerations.
3641 : * Usually that means we have a restriction clause WHERE indexcol = constant,
3642 : * which gets turned into an EquivalenceClass containing a constant, which
3643 : * is recognized as redundant by build_index_pathkeys(). But if the index
3644 : * column is a boolean variable (or expression), then we are not going to
3645 : * see WHERE indexcol = constant, because expression preprocessing will have
3646 : * simplified that to "WHERE indexcol" or "WHERE NOT indexcol". So we are not
3647 : * going to have a matching EquivalenceClass (unless the query also contains
3648 : * "ORDER BY indexcol"). To allow such cases to work the same as they would
3649 : * for non-boolean values, this function is provided to detect whether the
3650 : * specified index column matches a boolean restriction clause.
3651 : */
3652 : bool
3653 508920 : indexcol_is_bool_constant_for_query(PlannerInfo *root,
3654 : IndexOptInfo *index,
3655 : int indexcol)
3656 : {
3657 : ListCell *lc;
3658 :
3659 : /* If the index isn't boolean, we can't possibly get a match */
3660 508920 : if (!IsBooleanOpfamily(index->opfamily[indexcol]))
3661 508308 : return false;
3662 :
3663 : /* Check each restriction clause for the index's rel */
3664 648 : foreach(lc, index->rel->baserestrictinfo)
3665 : {
3666 144 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
3667 :
3668 : /*
3669 : * As in match_clause_to_indexcol, never match pseudoconstants to
3670 : * indexes. (It might be semantically okay to do so here, but the
3671 : * odds of getting a match are negligible, so don't waste the cycles.)
3672 : */
3673 144 : if (rinfo->pseudoconstant)
3674 0 : continue;
3675 :
3676 : /* See if we can match the clause's expression to the index column */
3677 144 : if (match_boolean_index_clause(root, rinfo, indexcol, index))
3678 108 : return true;
3679 : }
3680 :
3681 504 : return false;
3682 : }
3683 :
3684 :
3685 : /****************************************************************************
3686 : * ---- ROUTINES TO CHECK OPERANDS ----
3687 : ****************************************************************************/
3688 :
3689 : /*
3690 : * match_index_to_operand()
3691 : * Generalized test for a match between an index's key
3692 : * and the operand on one side of a restriction or join clause.
3693 : *
3694 : * operand: the nodetree to be compared to the index
3695 : * indexcol: the column number of the index (counting from 0)
3696 : * index: the index of interest
3697 : *
3698 : * Note that we aren't interested in collations here; the caller must check
3699 : * for a collation match, if it's dealing with an operator where that matters.
3700 : *
3701 : * This is exported for use in selfuncs.c.
3702 : */
3703 : bool
3704 2947352 : match_index_to_operand(Node *operand,
3705 : int indexcol,
3706 : IndexOptInfo *index)
3707 : {
3708 : int indkey;
3709 :
3710 : /*
3711 : * Ignore any RelabelType node above the operand. This is needed to be
3712 : * able to apply indexscanning in binary-compatible-operator cases. Note:
3713 : * we can assume there is at most one RelabelType node;
3714 : * eval_const_expressions() will have simplified if more than one.
3715 : */
3716 2947352 : if (operand && IsA(operand, RelabelType))
3717 20952 : operand = (Node *) ((RelabelType *) operand)->arg;
3718 :
3719 2947352 : indkey = index->indexkeys[indexcol];
3720 2947352 : if (indkey != 0)
3721 : {
3722 : /*
3723 : * Simple index column; operand must be a matching Var.
3724 : */
3725 2941234 : if (operand && IsA(operand, Var) &&
3726 2173058 : index->rel->relid == ((Var *) operand)->varno &&
3727 1997624 : indkey == ((Var *) operand)->varattno &&
3728 690484 : ((Var *) operand)->varnullingrels == NULL)
3729 685334 : return true;
3730 : }
3731 : else
3732 : {
3733 : /*
3734 : * Index expression; find the correct expression. (This search could
3735 : * be avoided, at the cost of complicating all the callers of this
3736 : * routine; doesn't seem worth it.)
3737 : */
3738 : ListCell *indexpr_item;
3739 : int i;
3740 : Node *indexkey;
3741 :
3742 6118 : indexpr_item = list_head(index->indexprs);
3743 6118 : for (i = 0; i < indexcol; i++)
3744 : {
3745 0 : if (index->indexkeys[i] == 0)
3746 : {
3747 0 : if (indexpr_item == NULL)
3748 0 : elog(ERROR, "wrong number of index expressions");
3749 0 : indexpr_item = lnext(index->indexprs, indexpr_item);
3750 : }
3751 : }
3752 6118 : if (indexpr_item == NULL)
3753 0 : elog(ERROR, "wrong number of index expressions");
3754 6118 : indexkey = (Node *) lfirst(indexpr_item);
3755 :
3756 : /*
3757 : * Does it match the operand? Again, strip any relabeling.
3758 : */
3759 6118 : if (indexkey && IsA(indexkey, RelabelType))
3760 10 : indexkey = (Node *) ((RelabelType *) indexkey)->arg;
3761 :
3762 6118 : if (equal(indexkey, operand))
3763 2164 : return true;
3764 : }
3765 :
3766 2259854 : return false;
3767 : }
3768 :
3769 : /*
3770 : * is_pseudo_constant_for_index()
3771 : * Test whether the given expression can be used as an indexscan
3772 : * comparison value.
3773 : *
3774 : * An indexscan comparison value must not contain any volatile functions,
3775 : * and it can't contain any Vars of the index's own table. Vars of
3776 : * other tables are okay, though; in that case we'd be producing an
3777 : * indexqual usable in a parameterized indexscan. This is, therefore,
3778 : * a weaker condition than is_pseudo_constant_clause().
3779 : *
3780 : * This function is exported for use by planner support functions,
3781 : * which will have available the IndexOptInfo, but not any RestrictInfo
3782 : * infrastructure. It is making the same test made by functions above
3783 : * such as match_opclause_to_indexcol(), but those rely where possible
3784 : * on RestrictInfo information about variable membership.
3785 : *
3786 : * expr: the nodetree to be checked
3787 : * index: the index of interest
3788 : */
3789 : bool
3790 0 : is_pseudo_constant_for_index(PlannerInfo *root, Node *expr, IndexOptInfo *index)
3791 : {
3792 : /* pull_varnos is cheaper than volatility check, so do that first */
3793 0 : if (bms_is_member(index->rel->relid, pull_varnos(root, expr)))
3794 0 : return false; /* no good, contains Var of table */
3795 0 : if (contain_volatile_functions(expr))
3796 0 : return false; /* no good, volatile comparison value */
3797 0 : return true;
3798 : }
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