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) 1996-2019, 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 bool bms_equal_any(Relids relids, List *relids_list);
103 : static void get_index_paths(PlannerInfo *root, RelOptInfo *rel,
104 : IndexOptInfo *index, IndexClauseSet *clauses,
105 : List **bitindexpaths);
106 : static List *build_index_paths(PlannerInfo *root, RelOptInfo *rel,
107 : IndexOptInfo *index, IndexClauseSet *clauses,
108 : bool useful_predicate,
109 : ScanTypeControl scantype,
110 : bool *skip_nonnative_saop,
111 : bool *skip_lower_saop);
112 : static List *build_paths_for_OR(PlannerInfo *root, RelOptInfo *rel,
113 : List *clauses, List *other_clauses);
114 : static List *generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel,
115 : List *clauses, List *other_clauses);
116 : static Path *choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel,
117 : List *paths);
118 : static int path_usage_comparator(const void *a, const void *b);
119 : static Cost bitmap_scan_cost_est(PlannerInfo *root, RelOptInfo *rel,
120 : Path *ipath);
121 : static Cost bitmap_and_cost_est(PlannerInfo *root, RelOptInfo *rel,
122 : List *paths);
123 : static PathClauseUsage *classify_index_clause_usage(Path *path,
124 : List **clauselist);
125 : static Relids get_bitmap_tree_required_outer(Path *bitmapqual);
126 : static void find_indexpath_quals(Path *bitmapqual, List **quals, List **preds);
127 : static int find_list_position(Node *node, List **nodelist);
128 : static bool check_index_only(RelOptInfo *rel, IndexOptInfo *index);
129 : static double get_loop_count(PlannerInfo *root, Index cur_relid, Relids outer_relids);
130 : static double adjust_rowcount_for_semijoins(PlannerInfo *root,
131 : Index cur_relid,
132 : Index outer_relid,
133 : double rowcount);
134 : static double approximate_joinrel_size(PlannerInfo *root, Relids relids);
135 : static void match_restriction_clauses_to_index(PlannerInfo *root,
136 : IndexOptInfo *index,
137 : IndexClauseSet *clauseset);
138 : static void match_join_clauses_to_index(PlannerInfo *root,
139 : RelOptInfo *rel, IndexOptInfo *index,
140 : IndexClauseSet *clauseset,
141 : List **joinorclauses);
142 : static void match_eclass_clauses_to_index(PlannerInfo *root,
143 : IndexOptInfo *index,
144 : IndexClauseSet *clauseset);
145 : static void match_clauses_to_index(PlannerInfo *root,
146 : List *clauses,
147 : IndexOptInfo *index,
148 : IndexClauseSet *clauseset);
149 : static void match_clause_to_index(PlannerInfo *root,
150 : RestrictInfo *rinfo,
151 : IndexOptInfo *index,
152 : IndexClauseSet *clauseset);
153 : static IndexClause *match_clause_to_indexcol(PlannerInfo *root,
154 : RestrictInfo *rinfo,
155 : int indexcol,
156 : IndexOptInfo *index);
157 : static IndexClause *match_boolean_index_clause(RestrictInfo *rinfo,
158 : int indexcol, IndexOptInfo *index);
159 : static IndexClause *match_opclause_to_indexcol(PlannerInfo *root,
160 : RestrictInfo *rinfo,
161 : int indexcol,
162 : IndexOptInfo *index);
163 : static IndexClause *match_funcclause_to_indexcol(PlannerInfo *root,
164 : RestrictInfo *rinfo,
165 : int indexcol,
166 : IndexOptInfo *index);
167 : static IndexClause *get_index_clause_from_support(PlannerInfo *root,
168 : RestrictInfo *rinfo,
169 : Oid funcid,
170 : int indexarg,
171 : int indexcol,
172 : IndexOptInfo *index);
173 : static IndexClause *match_saopclause_to_indexcol(RestrictInfo *rinfo,
174 : int indexcol,
175 : IndexOptInfo *index);
176 : static IndexClause *match_rowcompare_to_indexcol(RestrictInfo *rinfo,
177 : int indexcol,
178 : IndexOptInfo *index);
179 : static IndexClause *expand_indexqual_rowcompare(RestrictInfo *rinfo,
180 : int indexcol,
181 : IndexOptInfo *index,
182 : Oid expr_op,
183 : bool var_on_left);
184 : static void match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys,
185 : List **orderby_clauses_p,
186 : List **clause_columns_p);
187 : static Expr *match_clause_to_ordering_op(IndexOptInfo *index,
188 : int indexcol, Expr *clause, Oid pk_opfamily);
189 : static bool ec_member_matches_indexcol(PlannerInfo *root, RelOptInfo *rel,
190 : EquivalenceClass *ec, EquivalenceMember *em,
191 : void *arg);
192 :
193 :
194 : /*
195 : * create_index_paths()
196 : * Generate all interesting index paths for the given relation.
197 : * Candidate paths are added to the rel's pathlist (using add_path).
198 : *
199 : * To be considered for an index scan, an index must match one or more
200 : * restriction clauses or join clauses from the query's qual condition,
201 : * or match the query's ORDER BY condition, or have a predicate that
202 : * matches the query's qual condition.
203 : *
204 : * There are two basic kinds of index scans. A "plain" index scan uses
205 : * only restriction clauses (possibly none at all) in its indexqual,
206 : * so it can be applied in any context. A "parameterized" index scan uses
207 : * join clauses (plus restriction clauses, if available) in its indexqual.
208 : * When joining such a scan to one of the relations supplying the other
209 : * variables used in its indexqual, the parameterized scan must appear as
210 : * the inner relation of a nestloop join; it can't be used on the outer side,
211 : * nor in a merge or hash join. In that context, values for the other rels'
212 : * attributes are available and fixed during any one scan of the indexpath.
213 : *
214 : * An IndexPath is generated and submitted to add_path() for each plain or
215 : * parameterized index scan this routine deems potentially interesting for
216 : * the current query.
217 : *
218 : * 'rel' is the relation for which we want to generate index paths
219 : *
220 : * Note: check_index_predicates() must have been run previously for this rel.
221 : *
222 : * Note: in cases involving LATERAL references in the relation's tlist, it's
223 : * possible that rel->lateral_relids is nonempty. Currently, we include
224 : * lateral_relids into the parameterization reported for each path, but don't
225 : * take it into account otherwise. The fact that any such rels *must* be
226 : * available as parameter sources perhaps should influence our choices of
227 : * index quals ... but for now, it doesn't seem worth troubling over.
228 : * In particular, comments below about "unparameterized" paths should be read
229 : * as meaning "unparameterized so far as the indexquals are concerned".
230 : */
231 : void
232 216576 : create_index_paths(PlannerInfo *root, RelOptInfo *rel)
233 : {
234 : List *indexpaths;
235 : List *bitindexpaths;
236 : List *bitjoinpaths;
237 : List *joinorclauses;
238 : IndexClauseSet rclauseset;
239 : IndexClauseSet jclauseset;
240 : IndexClauseSet eclauseset;
241 : ListCell *lc;
242 :
243 : /* Skip the whole mess if no indexes */
244 216576 : if (rel->indexlist == NIL)
245 37276 : return;
246 :
247 : /* Bitmap paths are collected and then dealt with at the end */
248 179300 : bitindexpaths = bitjoinpaths = joinorclauses = NIL;
249 :
250 : /* Examine each index in turn */
251 554038 : foreach(lc, rel->indexlist)
252 : {
253 374738 : IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
254 :
255 : /* Protect limited-size array in IndexClauseSets */
256 : Assert(index->nkeycolumns <= INDEX_MAX_KEYS);
257 :
258 : /*
259 : * Ignore partial indexes that do not match the query.
260 : * (generate_bitmap_or_paths() might be able to do something with
261 : * them, but that's of no concern here.)
262 : */
263 374738 : if (index->indpred != NIL && !index->predOK)
264 330 : continue;
265 :
266 : /*
267 : * Identify the restriction clauses that can match the index.
268 : */
269 374408 : MemSet(&rclauseset, 0, sizeof(rclauseset));
270 374408 : match_restriction_clauses_to_index(root, index, &rclauseset);
271 :
272 : /*
273 : * Build index paths from the restriction clauses. These will be
274 : * non-parameterized paths. Plain paths go directly to add_path(),
275 : * bitmap paths are added to bitindexpaths to be handled below.
276 : */
277 374408 : get_index_paths(root, rel, index, &rclauseset,
278 : &bitindexpaths);
279 :
280 : /*
281 : * Identify the join clauses that can match the index. For the moment
282 : * we keep them separate from the restriction clauses. Note that this
283 : * step finds only "loose" join clauses that have not been merged into
284 : * EquivalenceClasses. Also, collect join OR clauses for later.
285 : */
286 374408 : MemSet(&jclauseset, 0, sizeof(jclauseset));
287 374408 : match_join_clauses_to_index(root, rel, index,
288 : &jclauseset, &joinorclauses);
289 :
290 : /*
291 : * Look for EquivalenceClasses that can generate joinclauses matching
292 : * the index.
293 : */
294 374408 : MemSet(&eclauseset, 0, sizeof(eclauseset));
295 374408 : match_eclass_clauses_to_index(root, index,
296 : &eclauseset);
297 :
298 : /*
299 : * If we found any plain or eclass join clauses, build parameterized
300 : * index paths using them.
301 : */
302 374408 : if (jclauseset.nonempty || eclauseset.nonempty)
303 57176 : consider_index_join_clauses(root, rel, index,
304 : &rclauseset,
305 : &jclauseset,
306 : &eclauseset,
307 : &bitjoinpaths);
308 : }
309 :
310 : /*
311 : * Generate BitmapOrPaths for any suitable OR-clauses present in the
312 : * restriction list. Add these to bitindexpaths.
313 : */
314 179300 : indexpaths = generate_bitmap_or_paths(root, rel,
315 : rel->baserestrictinfo, NIL);
316 179300 : bitindexpaths = list_concat(bitindexpaths, indexpaths);
317 :
318 : /*
319 : * Likewise, generate BitmapOrPaths for any suitable OR-clauses present in
320 : * the joinclause list. Add these to bitjoinpaths.
321 : */
322 179300 : indexpaths = generate_bitmap_or_paths(root, rel,
323 : joinorclauses, rel->baserestrictinfo);
324 179300 : bitjoinpaths = list_concat(bitjoinpaths, indexpaths);
325 :
326 : /*
327 : * If we found anything usable, generate a BitmapHeapPath for the most
328 : * promising combination of restriction bitmap index paths. Note there
329 : * will be only one such path no matter how many indexes exist. This
330 : * should be sufficient since there's basically only one figure of merit
331 : * (total cost) for such a path.
332 : */
333 179300 : if (bitindexpaths != NIL)
334 : {
335 : Path *bitmapqual;
336 : BitmapHeapPath *bpath;
337 :
338 114560 : bitmapqual = choose_bitmap_and(root, rel, bitindexpaths);
339 114560 : bpath = create_bitmap_heap_path(root, rel, bitmapqual,
340 : rel->lateral_relids, 1.0, 0);
341 114560 : add_path(rel, (Path *) bpath);
342 :
343 : /* create a partial bitmap heap path */
344 114560 : if (rel->consider_parallel && rel->lateral_relids == NULL)
345 73110 : create_partial_bitmap_paths(root, rel, bitmapqual);
346 : }
347 :
348 : /*
349 : * Likewise, if we found anything usable, generate BitmapHeapPaths for the
350 : * most promising combinations of join bitmap index paths. Our strategy
351 : * is to generate one such path for each distinct parameterization seen
352 : * among the available bitmap index paths. This may look pretty
353 : * expensive, but usually there won't be very many distinct
354 : * parameterizations. (This logic is quite similar to that in
355 : * consider_index_join_clauses, but we're working with whole paths not
356 : * individual clauses.)
357 : */
358 179300 : if (bitjoinpaths != NIL)
359 : {
360 : List *path_outer;
361 : List *all_path_outers;
362 : ListCell *lc;
363 :
364 : /*
365 : * path_outer holds the parameterization of each path in bitjoinpaths
366 : * (to save recalculating that several times), while all_path_outers
367 : * holds all distinct parameterization sets.
368 : */
369 54630 : path_outer = all_path_outers = NIL;
370 113684 : foreach(lc, bitjoinpaths)
371 : {
372 59054 : Path *path = (Path *) lfirst(lc);
373 : Relids required_outer;
374 :
375 59054 : required_outer = get_bitmap_tree_required_outer(path);
376 59054 : path_outer = lappend(path_outer, required_outer);
377 59054 : if (!bms_equal_any(required_outer, all_path_outers))
378 57708 : all_path_outers = lappend(all_path_outers, required_outer);
379 : }
380 :
381 : /* Now, for each distinct parameterization set ... */
382 112338 : foreach(lc, all_path_outers)
383 : {
384 57708 : Relids max_outers = (Relids) lfirst(lc);
385 : List *this_path_set;
386 : Path *bitmapqual;
387 : Relids required_outer;
388 : double loop_count;
389 : BitmapHeapPath *bpath;
390 : ListCell *lcp;
391 : ListCell *lco;
392 :
393 : /* Identify all the bitmap join paths needing no more than that */
394 57708 : this_path_set = NIL;
395 124466 : forboth(lcp, bitjoinpaths, lco, path_outer)
396 : {
397 66758 : Path *path = (Path *) lfirst(lcp);
398 66758 : Relids p_outers = (Relids) lfirst(lco);
399 :
400 66758 : if (bms_is_subset(p_outers, max_outers))
401 59454 : this_path_set = lappend(this_path_set, path);
402 : }
403 :
404 : /*
405 : * Add in restriction bitmap paths, since they can be used
406 : * together with any join paths.
407 : */
408 57708 : this_path_set = list_concat(this_path_set, bitindexpaths);
409 :
410 : /* Select best AND combination for this parameterization */
411 57708 : bitmapqual = choose_bitmap_and(root, rel, this_path_set);
412 :
413 : /* And push that path into the mix */
414 57708 : required_outer = get_bitmap_tree_required_outer(bitmapqual);
415 57708 : loop_count = get_loop_count(root, rel->relid, required_outer);
416 57708 : bpath = create_bitmap_heap_path(root, rel, bitmapqual,
417 : required_outer, loop_count, 0);
418 57708 : add_path(rel, (Path *) bpath);
419 : }
420 : }
421 : }
422 :
423 : /*
424 : * consider_index_join_clauses
425 : * Given sets of join clauses for an index, decide which parameterized
426 : * index paths to build.
427 : *
428 : * Plain indexpaths are sent directly to add_path, while potential
429 : * bitmap indexpaths are added to *bitindexpaths for later processing.
430 : *
431 : * 'rel' is the index's heap relation
432 : * 'index' is the index for which we want to generate paths
433 : * 'rclauseset' is the collection of indexable restriction clauses
434 : * 'jclauseset' is the collection of indexable simple join clauses
435 : * 'eclauseset' is the collection of indexable clauses from EquivalenceClasses
436 : * '*bitindexpaths' is the list to add bitmap paths to
437 : */
438 : static void
439 57176 : consider_index_join_clauses(PlannerInfo *root, RelOptInfo *rel,
440 : IndexOptInfo *index,
441 : IndexClauseSet *rclauseset,
442 : IndexClauseSet *jclauseset,
443 : IndexClauseSet *eclauseset,
444 : List **bitindexpaths)
445 : {
446 57176 : int considered_clauses = 0;
447 57176 : List *considered_relids = NIL;
448 : int indexcol;
449 :
450 : /*
451 : * The strategy here is to identify every potentially useful set of outer
452 : * rels that can provide indexable join clauses. For each such set,
453 : * select all the join clauses available from those outer rels, add on all
454 : * the indexable restriction clauses, and generate plain and/or bitmap
455 : * index paths for that set of clauses. This is based on the assumption
456 : * that it's always better to apply a clause as an indexqual than as a
457 : * filter (qpqual); which is where an available clause would end up being
458 : * applied if we omit it from the indexquals.
459 : *
460 : * This looks expensive, but in most practical cases there won't be very
461 : * many distinct sets of outer rels to consider. As a safety valve when
462 : * that's not true, we use a heuristic: limit the number of outer rel sets
463 : * considered to a multiple of the number of clauses considered. (We'll
464 : * always consider using each individual join clause, though.)
465 : *
466 : * For simplicity in selecting relevant clauses, we represent each set of
467 : * outer rels as a maximum set of clause_relids --- that is, the indexed
468 : * relation itself is also included in the relids set. considered_relids
469 : * lists all relids sets we've already tried.
470 : */
471 142262 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
472 : {
473 : /* Consider each applicable simple join clause */
474 85086 : considered_clauses += list_length(jclauseset->indexclauses[indexcol]);
475 85086 : consider_index_join_outer_rels(root, rel, index,
476 : rclauseset, jclauseset, eclauseset,
477 : bitindexpaths,
478 : jclauseset->indexclauses[indexcol],
479 : considered_clauses,
480 : &considered_relids);
481 : /* Consider each applicable eclass join clause */
482 85086 : considered_clauses += list_length(eclauseset->indexclauses[indexcol]);
483 85086 : consider_index_join_outer_rels(root, rel, index,
484 : rclauseset, jclauseset, eclauseset,
485 : bitindexpaths,
486 : eclauseset->indexclauses[indexcol],
487 : considered_clauses,
488 : &considered_relids);
489 : }
490 57176 : }
491 :
492 : /*
493 : * consider_index_join_outer_rels
494 : * Generate parameterized paths based on clause relids in the clause list.
495 : *
496 : * Workhorse for consider_index_join_clauses; see notes therein for rationale.
497 : *
498 : * 'rel', 'index', 'rclauseset', 'jclauseset', 'eclauseset', and
499 : * 'bitindexpaths' as above
500 : * 'indexjoinclauses' is a list of IndexClauses for join clauses
501 : * 'considered_clauses' is the total number of clauses considered (so far)
502 : * '*considered_relids' is a list of all relids sets already considered
503 : */
504 : static void
505 170172 : consider_index_join_outer_rels(PlannerInfo *root, RelOptInfo *rel,
506 : IndexOptInfo *index,
507 : IndexClauseSet *rclauseset,
508 : IndexClauseSet *jclauseset,
509 : IndexClauseSet *eclauseset,
510 : List **bitindexpaths,
511 : List *indexjoinclauses,
512 : int considered_clauses,
513 : List **considered_relids)
514 : {
515 : ListCell *lc;
516 :
517 : /* Examine relids of each joinclause in the given list */
518 230286 : foreach(lc, indexjoinclauses)
519 : {
520 60114 : IndexClause *iclause = (IndexClause *) lfirst(lc);
521 60114 : Relids clause_relids = iclause->rinfo->clause_relids;
522 60114 : EquivalenceClass *parent_ec = iclause->rinfo->parent_ec;
523 : ListCell *lc2;
524 :
525 : /* If we already tried its relids set, no need to do so again */
526 60114 : if (bms_equal_any(clause_relids, *considered_relids))
527 1326 : continue;
528 :
529 : /*
530 : * Generate the union of this clause's relids set with each
531 : * previously-tried set. This ensures we try this clause along with
532 : * every interesting subset of previous clauses. However, to avoid
533 : * exponential growth of planning time when there are many clauses,
534 : * limit the number of relid sets accepted to 10 * considered_clauses.
535 : *
536 : * Note: get_join_index_paths adds entries to *considered_relids, but
537 : * it prepends them to the list, so that we won't visit new entries
538 : * during the inner foreach loop. No real harm would be done if we
539 : * did, since the subset check would reject them; but it would waste
540 : * some cycles.
541 : */
542 60440 : foreach(lc2, *considered_relids)
543 : {
544 1652 : Relids oldrelids = (Relids) lfirst(lc2);
545 :
546 : /*
547 : * If either is a subset of the other, no new set is possible.
548 : * This isn't a complete test for redundancy, but it's easy and
549 : * cheap. get_join_index_paths will check more carefully if we
550 : * already generated the same relids set.
551 : */
552 1652 : if (bms_subset_compare(clause_relids, oldrelids) != BMS_DIFFERENT)
553 16 : continue;
554 :
555 : /*
556 : * If this clause was derived from an equivalence class, the
557 : * clause list may contain other clauses derived from the same
558 : * eclass. We should not consider that combining this clause with
559 : * one of those clauses generates a usefully different
560 : * parameterization; so skip if any clause derived from the same
561 : * eclass would already have been included when using oldrelids.
562 : */
563 3174 : if (parent_ec &&
564 1538 : eclass_already_used(parent_ec, oldrelids,
565 : indexjoinclauses))
566 1472 : continue;
567 :
568 : /*
569 : * If the number of relid sets considered exceeds our heuristic
570 : * limit, stop considering combinations of clauses. We'll still
571 : * consider the current clause alone, though (below this loop).
572 : */
573 164 : if (list_length(*considered_relids) >= 10 * considered_clauses)
574 0 : break;
575 :
576 : /* OK, try the union set */
577 164 : get_join_index_paths(root, rel, index,
578 : rclauseset, jclauseset, eclauseset,
579 : bitindexpaths,
580 : bms_union(clause_relids, oldrelids),
581 : considered_relids);
582 : }
583 :
584 : /* Also try this set of relids by itself */
585 58788 : get_join_index_paths(root, rel, index,
586 : rclauseset, jclauseset, eclauseset,
587 : bitindexpaths,
588 : clause_relids,
589 : considered_relids);
590 : }
591 170172 : }
592 :
593 : /*
594 : * get_join_index_paths
595 : * Generate index paths using clauses from the specified outer relations.
596 : * In addition to generating paths, relids is added to *considered_relids
597 : * if not already present.
598 : *
599 : * Workhorse for consider_index_join_clauses; see notes therein for rationale.
600 : *
601 : * 'rel', 'index', 'rclauseset', 'jclauseset', 'eclauseset',
602 : * 'bitindexpaths', 'considered_relids' as above
603 : * 'relids' is the current set of relids to consider (the target rel plus
604 : * one or more outer rels)
605 : */
606 : static void
607 58952 : get_join_index_paths(PlannerInfo *root, RelOptInfo *rel,
608 : IndexOptInfo *index,
609 : IndexClauseSet *rclauseset,
610 : IndexClauseSet *jclauseset,
611 : IndexClauseSet *eclauseset,
612 : List **bitindexpaths,
613 : Relids relids,
614 : List **considered_relids)
615 : {
616 : IndexClauseSet clauseset;
617 : int indexcol;
618 :
619 : /* If we already considered this relids set, don't repeat the work */
620 58952 : if (bms_equal_any(relids, *considered_relids))
621 0 : return;
622 :
623 : /* Identify indexclauses usable with this relids set */
624 58952 : MemSet(&clauseset, 0, sizeof(clauseset));
625 :
626 147226 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
627 : {
628 : ListCell *lc;
629 :
630 : /* First find applicable simple join clauses */
631 112560 : foreach(lc, jclauseset->indexclauses[indexcol])
632 : {
633 24286 : IndexClause *iclause = (IndexClause *) lfirst(lc);
634 :
635 24286 : if (bms_is_subset(iclause->rinfo->clause_relids, relids))
636 24068 : clauseset.indexclauses[indexcol] =
637 24068 : lappend(clauseset.indexclauses[indexcol], iclause);
638 : }
639 :
640 : /*
641 : * Add applicable eclass join clauses. The clauses generated for each
642 : * column are redundant (cf generate_implied_equalities_for_column),
643 : * so we need at most one. This is the only exception to the general
644 : * rule of using all available index clauses.
645 : */
646 90126 : foreach(lc, eclauseset->indexclauses[indexcol])
647 : {
648 38214 : IndexClause *iclause = (IndexClause *) lfirst(lc);
649 :
650 38214 : if (bms_is_subset(iclause->rinfo->clause_relids, relids))
651 : {
652 36362 : clauseset.indexclauses[indexcol] =
653 36362 : lappend(clauseset.indexclauses[indexcol], iclause);
654 36362 : break;
655 : }
656 : }
657 :
658 : /* Add restriction clauses (this is nondestructive to rclauseset) */
659 88274 : clauseset.indexclauses[indexcol] =
660 88274 : list_concat(clauseset.indexclauses[indexcol],
661 : rclauseset->indexclauses[indexcol]);
662 :
663 88274 : if (clauseset.indexclauses[indexcol] != NIL)
664 73570 : clauseset.nonempty = true;
665 : }
666 :
667 : /* We should have found something, else caller passed silly relids */
668 : Assert(clauseset.nonempty);
669 :
670 : /* Build index path(s) using the collected set of clauses */
671 58952 : get_index_paths(root, rel, index, &clauseset, bitindexpaths);
672 :
673 : /*
674 : * Remember we considered paths for this set of relids. We use lcons not
675 : * lappend to avoid confusing the loop in consider_index_join_outer_rels.
676 : */
677 58952 : *considered_relids = lcons(relids, *considered_relids);
678 : }
679 :
680 : /*
681 : * eclass_already_used
682 : * True if any join clause usable with oldrelids was generated from
683 : * the specified equivalence class.
684 : */
685 : static bool
686 1538 : eclass_already_used(EquivalenceClass *parent_ec, Relids oldrelids,
687 : List *indexjoinclauses)
688 : {
689 : ListCell *lc;
690 :
691 1636 : foreach(lc, indexjoinclauses)
692 : {
693 1570 : IndexClause *iclause = (IndexClause *) lfirst(lc);
694 1570 : RestrictInfo *rinfo = iclause->rinfo;
695 :
696 3140 : if (rinfo->parent_ec == parent_ec &&
697 1570 : bms_is_subset(rinfo->clause_relids, oldrelids))
698 1472 : return true;
699 : }
700 66 : return false;
701 : }
702 :
703 : /*
704 : * bms_equal_any
705 : * True if relids is bms_equal to any member of relids_list
706 : *
707 : * Perhaps this should be in bitmapset.c someday.
708 : */
709 : static bool
710 178120 : bms_equal_any(Relids relids, List *relids_list)
711 : {
712 : ListCell *lc;
713 :
714 185656 : foreach(lc, relids_list)
715 : {
716 10208 : if (bms_equal(relids, (Relids) lfirst(lc)))
717 2672 : return true;
718 : }
719 175448 : return false;
720 : }
721 :
722 :
723 : /*
724 : * get_index_paths
725 : * Given an index and a set of index clauses for it, construct IndexPaths.
726 : *
727 : * Plain indexpaths are sent directly to add_path, while potential
728 : * bitmap indexpaths are added to *bitindexpaths for later processing.
729 : *
730 : * This is a fairly simple frontend to build_index_paths(). Its reason for
731 : * existence is mainly to handle ScalarArrayOpExpr quals properly. If the
732 : * index AM supports them natively, we should just include them in simple
733 : * index paths. If not, we should exclude them while building simple index
734 : * paths, and then make a separate attempt to include them in bitmap paths.
735 : * Furthermore, we should consider excluding lower-order ScalarArrayOpExpr
736 : * quals so as to create ordered paths.
737 : */
738 : static void
739 433360 : get_index_paths(PlannerInfo *root, RelOptInfo *rel,
740 : IndexOptInfo *index, IndexClauseSet *clauses,
741 : List **bitindexpaths)
742 : {
743 : List *indexpaths;
744 433360 : bool skip_nonnative_saop = false;
745 433360 : bool skip_lower_saop = false;
746 : ListCell *lc;
747 :
748 : /*
749 : * Build simple index paths using the clauses. Allow ScalarArrayOpExpr
750 : * clauses only if the index AM supports them natively, and skip any such
751 : * clauses for index columns after the first (so that we produce ordered
752 : * paths if possible).
753 : */
754 433360 : indexpaths = build_index_paths(root, rel,
755 : index, clauses,
756 433360 : index->predOK,
757 : ST_ANYSCAN,
758 : &skip_nonnative_saop,
759 : &skip_lower_saop);
760 :
761 : /*
762 : * If we skipped any lower-order ScalarArrayOpExprs on an index with an AM
763 : * that supports them, then try again including those clauses. This will
764 : * produce paths with more selectivity but no ordering.
765 : */
766 433360 : if (skip_lower_saop)
767 : {
768 44 : indexpaths = list_concat(indexpaths,
769 : build_index_paths(root, rel,
770 : index, clauses,
771 44 : index->predOK,
772 : ST_ANYSCAN,
773 : &skip_nonnative_saop,
774 : NULL));
775 : }
776 :
777 : /*
778 : * Submit all the ones that can form plain IndexScan plans to add_path. (A
779 : * plain IndexPath can represent either a plain IndexScan or an
780 : * IndexOnlyScan, but for our purposes here that distinction does not
781 : * matter. However, some of the indexes might support only bitmap scans,
782 : * and those we mustn't submit to add_path here.)
783 : *
784 : * Also, pick out the ones that are usable as bitmap scans. For that, we
785 : * must discard indexes that don't support bitmap scans, and we also are
786 : * only interested in paths that have some selectivity; we should discard
787 : * anything that was generated solely for ordering purposes.
788 : */
789 676104 : foreach(lc, indexpaths)
790 : {
791 242744 : IndexPath *ipath = (IndexPath *) lfirst(lc);
792 :
793 242744 : if (index->amhasgettuple)
794 237622 : add_path(rel, (Path *) ipath);
795 :
796 485488 : if (index->amhasgetbitmap &&
797 375426 : (ipath->path.pathkeys == NIL ||
798 132682 : ipath->indexselectivity < 1.0))
799 188844 : *bitindexpaths = lappend(*bitindexpaths, ipath);
800 : }
801 :
802 : /*
803 : * If there were ScalarArrayOpExpr clauses that the index can't handle
804 : * natively, generate bitmap scan paths relying on executor-managed
805 : * ScalarArrayOpExpr.
806 : */
807 433360 : if (skip_nonnative_saop)
808 : {
809 12 : indexpaths = build_index_paths(root, rel,
810 : index, clauses,
811 : false,
812 : ST_BITMAPSCAN,
813 : NULL,
814 : NULL);
815 12 : *bitindexpaths = list_concat(*bitindexpaths, indexpaths);
816 : }
817 433360 : }
818 :
819 : /*
820 : * build_index_paths
821 : * Given an index and a set of index clauses for it, construct zero
822 : * or more IndexPaths. It also constructs zero or more partial IndexPaths.
823 : *
824 : * We return a list of paths because (1) this routine checks some cases
825 : * that should cause us to not generate any IndexPath, and (2) in some
826 : * cases we want to consider both a forward and a backward scan, so as
827 : * to obtain both sort orders. Note that the paths are just returned
828 : * to the caller and not immediately fed to add_path().
829 : *
830 : * At top level, useful_predicate should be exactly the index's predOK flag
831 : * (ie, true if it has a predicate that was proven from the restriction
832 : * clauses). When working on an arm of an OR clause, useful_predicate
833 : * should be true if the predicate required the current OR list to be proven.
834 : * Note that this routine should never be called at all if the index has an
835 : * unprovable predicate.
836 : *
837 : * scantype indicates whether we want to create plain indexscans, bitmap
838 : * indexscans, or both. When it's ST_BITMAPSCAN, we will not consider
839 : * index ordering while deciding if a Path is worth generating.
840 : *
841 : * If skip_nonnative_saop is non-NULL, we ignore ScalarArrayOpExpr clauses
842 : * unless the index AM supports them directly, and we set *skip_nonnative_saop
843 : * to true if we found any such clauses (caller must initialize the variable
844 : * to false). If it's NULL, we do not ignore ScalarArrayOpExpr clauses.
845 : *
846 : * If skip_lower_saop is non-NULL, we ignore ScalarArrayOpExpr clauses for
847 : * non-first index columns, and we set *skip_lower_saop to true if we found
848 : * any such clauses (caller must initialize the variable to false). If it's
849 : * NULL, we do not ignore non-first ScalarArrayOpExpr clauses, but they will
850 : * result in considering the scan's output to be unordered.
851 : *
852 : * 'rel' is the index's heap relation
853 : * 'index' is the index for which we want to generate paths
854 : * 'clauses' is the collection of indexable clauses (IndexClause nodes)
855 : * 'useful_predicate' indicates whether the index has a useful predicate
856 : * 'scantype' indicates whether we need plain or bitmap scan support
857 : * 'skip_nonnative_saop' indicates whether to accept SAOP if index AM doesn't
858 : * 'skip_lower_saop' indicates whether to accept non-first-column SAOP
859 : */
860 : static List *
861 434232 : build_index_paths(PlannerInfo *root, RelOptInfo *rel,
862 : IndexOptInfo *index, IndexClauseSet *clauses,
863 : bool useful_predicate,
864 : ScanTypeControl scantype,
865 : bool *skip_nonnative_saop,
866 : bool *skip_lower_saop)
867 : {
868 434232 : List *result = NIL;
869 : IndexPath *ipath;
870 : List *index_clauses;
871 : Relids outer_relids;
872 : double loop_count;
873 : List *orderbyclauses;
874 : List *orderbyclausecols;
875 : List *index_pathkeys;
876 : List *useful_pathkeys;
877 : bool found_lower_saop_clause;
878 : bool pathkeys_possibly_useful;
879 : bool index_is_ordered;
880 : bool index_only_scan;
881 : int indexcol;
882 :
883 : /*
884 : * Check that index supports the desired scan type(s)
885 : */
886 434232 : switch (scantype)
887 : {
888 : case ST_INDEXSCAN:
889 0 : if (!index->amhasgettuple)
890 0 : return NIL;
891 0 : break;
892 : case ST_BITMAPSCAN:
893 828 : if (!index->amhasgetbitmap)
894 0 : return NIL;
895 828 : break;
896 : case ST_ANYSCAN:
897 : /* either or both are OK */
898 433404 : break;
899 : }
900 :
901 : /*
902 : * 1. Combine the per-column IndexClause lists into an overall list.
903 : *
904 : * In the resulting list, clauses are ordered by index key, so that the
905 : * column numbers form a nondecreasing sequence. (This order is depended
906 : * on by btree and possibly other places.) The list can be empty, if the
907 : * index AM allows that.
908 : *
909 : * found_lower_saop_clause is set true if we accept a ScalarArrayOpExpr
910 : * index clause for a non-first index column. This prevents us from
911 : * assuming that the scan result is ordered. (Actually, the result is
912 : * still ordered if there are equality constraints for all earlier
913 : * columns, but it seems too expensive and non-modular for this code to be
914 : * aware of that refinement.)
915 : *
916 : * We also build a Relids set showing which outer rels are required by the
917 : * selected clauses. Any lateral_relids are included in that, but not
918 : * otherwise accounted for.
919 : */
920 434232 : index_clauses = NIL;
921 434232 : found_lower_saop_clause = false;
922 434232 : outer_relids = bms_copy(rel->lateral_relids);
923 1204894 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
924 : {
925 : ListCell *lc;
926 :
927 992642 : foreach(lc, clauses->indexclauses[indexcol])
928 : {
929 221828 : IndexClause *iclause = (IndexClause *) lfirst(lc);
930 221828 : RestrictInfo *rinfo = iclause->rinfo;
931 :
932 : /* We might need to omit ScalarArrayOpExpr clauses */
933 221828 : if (IsA(rinfo->clause, ScalarArrayOpExpr))
934 : {
935 6760 : if (!index->amsearcharray)
936 : {
937 24 : if (skip_nonnative_saop)
938 : {
939 : /* Ignore because not supported by index */
940 12 : *skip_nonnative_saop = true;
941 12 : continue;
942 : }
943 : /* Caller had better intend this only for bitmap scan */
944 : Assert(scantype == ST_BITMAPSCAN);
945 : }
946 6748 : if (indexcol > 0)
947 : {
948 88 : if (skip_lower_saop)
949 : {
950 : /* Caller doesn't want to lose index ordering */
951 44 : *skip_lower_saop = true;
952 44 : continue;
953 : }
954 44 : found_lower_saop_clause = true;
955 : }
956 : }
957 :
958 : /* OK to include this clause */
959 221772 : index_clauses = lappend(index_clauses, iclause);
960 221772 : outer_relids = bms_add_members(outer_relids,
961 221772 : rinfo->clause_relids);
962 : }
963 :
964 : /*
965 : * If no clauses match the first index column, check for amoptionalkey
966 : * restriction. We can't generate a scan over an index with
967 : * amoptionalkey = false unless there's at least one index clause.
968 : * (When working on columns after the first, this test cannot fail. It
969 : * is always okay for columns after the first to not have any
970 : * clauses.)
971 : */
972 770814 : if (index_clauses == NIL && !index->amoptionalkey)
973 152 : return NIL;
974 : }
975 :
976 : /* We do not want the index's rel itself listed in outer_relids */
977 434080 : outer_relids = bms_del_member(outer_relids, rel->relid);
978 : /* Enforce convention that outer_relids is exactly NULL if empty */
979 434080 : if (bms_is_empty(outer_relids))
980 375036 : outer_relids = NULL;
981 :
982 : /* Compute loop_count for cost estimation purposes */
983 434080 : loop_count = get_loop_count(root, rel->relid, outer_relids);
984 :
985 : /*
986 : * 2. Compute pathkeys describing index's ordering, if any, then see how
987 : * many of them are actually useful for this query. This is not relevant
988 : * if we are only trying to build bitmap indexscans, nor if we have to
989 : * assume the scan is unordered.
990 : */
991 867332 : pathkeys_possibly_useful = (scantype != ST_BITMAPSCAN &&
992 867288 : !found_lower_saop_clause &&
993 433208 : has_useful_pathkeys(root, rel));
994 434080 : index_is_ordered = (index->sortopfamily != NULL);
995 434080 : if (index_is_ordered && pathkeys_possibly_useful)
996 : {
997 263530 : index_pathkeys = build_index_pathkeys(root, index,
998 : ForwardScanDirection);
999 263530 : useful_pathkeys = truncate_useless_pathkeys(root, rel,
1000 : index_pathkeys);
1001 263530 : orderbyclauses = NIL;
1002 263530 : orderbyclausecols = NIL;
1003 : }
1004 170550 : else if (index->amcanorderbyop && pathkeys_possibly_useful)
1005 : {
1006 : /* see if we can generate ordering operators for query_pathkeys */
1007 494 : match_pathkeys_to_index(index, root->query_pathkeys,
1008 : &orderbyclauses,
1009 : &orderbyclausecols);
1010 988 : if (orderbyclauses)
1011 268 : useful_pathkeys = root->query_pathkeys;
1012 : else
1013 226 : useful_pathkeys = NIL;
1014 : }
1015 : else
1016 : {
1017 170056 : useful_pathkeys = NIL;
1018 170056 : orderbyclauses = NIL;
1019 170056 : orderbyclausecols = NIL;
1020 : }
1021 :
1022 : /*
1023 : * 3. Check if an index-only scan is possible. If we're not building
1024 : * plain indexscans, this isn't relevant since bitmap scans don't support
1025 : * index data retrieval anyway.
1026 : */
1027 867332 : index_only_scan = (scantype != ST_BITMAPSCAN &&
1028 433252 : check_index_only(rel, index));
1029 :
1030 : /*
1031 : * 4. Generate an indexscan path if there are relevant restriction clauses
1032 : * in the current clauses, OR the index ordering is potentially useful for
1033 : * later merging or final output ordering, OR the index has a useful
1034 : * predicate, OR an index-only scan is possible.
1035 : */
1036 434080 : if (index_clauses != NIL || useful_pathkeys != NIL || useful_predicate ||
1037 : index_only_scan)
1038 : {
1039 243304 : ipath = create_index_path(root, index,
1040 : index_clauses,
1041 : orderbyclauses,
1042 : orderbyclausecols,
1043 : useful_pathkeys,
1044 : index_is_ordered ?
1045 : ForwardScanDirection :
1046 : NoMovementScanDirection,
1047 : index_only_scan,
1048 : outer_relids,
1049 : loop_count,
1050 : false);
1051 243304 : result = lappend(result, ipath);
1052 :
1053 : /*
1054 : * If appropriate, consider parallel index scan. We don't allow
1055 : * parallel index scan for bitmap index scans.
1056 : */
1057 478572 : if (index->amcanparallel &&
1058 410898 : rel->consider_parallel && outer_relids == NULL &&
1059 : scantype != ST_BITMAPSCAN)
1060 : {
1061 122440 : ipath = create_index_path(root, index,
1062 : index_clauses,
1063 : orderbyclauses,
1064 : orderbyclausecols,
1065 : useful_pathkeys,
1066 : index_is_ordered ?
1067 : ForwardScanDirection :
1068 : NoMovementScanDirection,
1069 : index_only_scan,
1070 : outer_relids,
1071 : loop_count,
1072 : true);
1073 :
1074 : /*
1075 : * if, after costing the path, we find that it's not worth using
1076 : * parallel workers, just free it.
1077 : */
1078 122440 : if (ipath->path.parallel_workers > 0)
1079 3088 : add_partial_path(rel, (Path *) ipath);
1080 : else
1081 119352 : pfree(ipath);
1082 : }
1083 : }
1084 :
1085 : /*
1086 : * 5. If the index is ordered, a backwards scan might be interesting.
1087 : */
1088 434080 : if (index_is_ordered && pathkeys_possibly_useful)
1089 : {
1090 263530 : index_pathkeys = build_index_pathkeys(root, index,
1091 : BackwardScanDirection);
1092 263530 : useful_pathkeys = truncate_useless_pathkeys(root, rel,
1093 : index_pathkeys);
1094 263530 : if (useful_pathkeys != NIL)
1095 : {
1096 268 : ipath = create_index_path(root, index,
1097 : index_clauses,
1098 : NIL,
1099 : NIL,
1100 : useful_pathkeys,
1101 : BackwardScanDirection,
1102 : index_only_scan,
1103 : outer_relids,
1104 : loop_count,
1105 : false);
1106 268 : result = lappend(result, ipath);
1107 :
1108 : /* If appropriate, consider parallel index scan */
1109 536 : if (index->amcanparallel &&
1110 500 : rel->consider_parallel && outer_relids == NULL &&
1111 : scantype != ST_BITMAPSCAN)
1112 : {
1113 232 : ipath = create_index_path(root, index,
1114 : index_clauses,
1115 : NIL,
1116 : NIL,
1117 : useful_pathkeys,
1118 : BackwardScanDirection,
1119 : index_only_scan,
1120 : outer_relids,
1121 : loop_count,
1122 : true);
1123 :
1124 : /*
1125 : * if, after costing the path, we find that it's not worth
1126 : * using parallel workers, just free it.
1127 : */
1128 232 : if (ipath->path.parallel_workers > 0)
1129 112 : add_partial_path(rel, (Path *) ipath);
1130 : else
1131 120 : pfree(ipath);
1132 : }
1133 : }
1134 : }
1135 :
1136 434080 : return result;
1137 : }
1138 :
1139 : /*
1140 : * build_paths_for_OR
1141 : * Given a list of restriction clauses from one arm of an OR clause,
1142 : * construct all matching IndexPaths for the relation.
1143 : *
1144 : * Here we must scan all indexes of the relation, since a bitmap OR tree
1145 : * can use multiple indexes.
1146 : *
1147 : * The caller actually supplies two lists of restriction clauses: some
1148 : * "current" ones and some "other" ones. Both lists can be used freely
1149 : * to match keys of the index, but an index must use at least one of the
1150 : * "current" clauses to be considered usable. The motivation for this is
1151 : * examples like
1152 : * WHERE (x = 42) AND (... OR (y = 52 AND z = 77) OR ....)
1153 : * While we are considering the y/z subclause of the OR, we can use "x = 42"
1154 : * as one of the available index conditions; but we shouldn't match the
1155 : * subclause to any index on x alone, because such a Path would already have
1156 : * been generated at the upper level. So we could use an index on x,y,z
1157 : * or an index on x,y for the OR subclause, but not an index on just x.
1158 : * When dealing with a partial index, a match of the index predicate to
1159 : * one of the "current" clauses also makes the index usable.
1160 : *
1161 : * 'rel' is the relation for which we want to generate index paths
1162 : * 'clauses' is the current list of clauses (RestrictInfo nodes)
1163 : * 'other_clauses' is the list of additional upper-level clauses
1164 : */
1165 : static List *
1166 13416 : build_paths_for_OR(PlannerInfo *root, RelOptInfo *rel,
1167 : List *clauses, List *other_clauses)
1168 : {
1169 13416 : List *result = NIL;
1170 13416 : List *all_clauses = NIL; /* not computed till needed */
1171 : ListCell *lc;
1172 :
1173 47256 : foreach(lc, rel->indexlist)
1174 : {
1175 33840 : IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
1176 : IndexClauseSet clauseset;
1177 : List *indexpaths;
1178 : bool useful_predicate;
1179 :
1180 : /* Ignore index if it doesn't support bitmap scans */
1181 33840 : if (!index->amhasgetbitmap)
1182 33024 : continue;
1183 :
1184 : /*
1185 : * Ignore partial indexes that do not match the query. If a partial
1186 : * index is marked predOK then we know it's OK. Otherwise, we have to
1187 : * test whether the added clauses are sufficient to imply the
1188 : * predicate. If so, we can use the index in the current context.
1189 : *
1190 : * We set useful_predicate to true iff the predicate was proven using
1191 : * the current set of clauses. This is needed to prevent matching a
1192 : * predOK index to an arm of an OR, which would be a legal but
1193 : * pointlessly inefficient plan. (A better plan will be generated by
1194 : * just scanning the predOK index alone, no OR.)
1195 : */
1196 33840 : useful_predicate = false;
1197 33840 : if (index->indpred != NIL)
1198 : {
1199 96 : if (index->predOK)
1200 : {
1201 : /* Usable, but don't set useful_predicate */
1202 : }
1203 : else
1204 : {
1205 : /* Form all_clauses if not done already */
1206 80 : if (all_clauses == NIL)
1207 32 : all_clauses = list_concat(list_copy(clauses),
1208 : other_clauses);
1209 :
1210 80 : if (!predicate_implied_by(index->indpred, all_clauses, false))
1211 56 : continue; /* can't use it at all */
1212 :
1213 24 : if (!predicate_implied_by(index->indpred, other_clauses, false))
1214 24 : useful_predicate = true;
1215 : }
1216 : }
1217 :
1218 : /*
1219 : * Identify the restriction clauses that can match the index.
1220 : */
1221 33784 : MemSet(&clauseset, 0, sizeof(clauseset));
1222 33784 : match_clauses_to_index(root, clauses, index, &clauseset);
1223 :
1224 : /*
1225 : * If no matches so far, and the index predicate isn't useful, we
1226 : * don't want it.
1227 : */
1228 33784 : if (!clauseset.nonempty && !useful_predicate)
1229 32968 : continue;
1230 :
1231 : /*
1232 : * Add "other" restriction clauses to the clauseset.
1233 : */
1234 816 : match_clauses_to_index(root, other_clauses, index, &clauseset);
1235 :
1236 : /*
1237 : * Construct paths if possible.
1238 : */
1239 816 : indexpaths = build_index_paths(root, rel,
1240 : index, &clauseset,
1241 : useful_predicate,
1242 : ST_BITMAPSCAN,
1243 : NULL,
1244 : NULL);
1245 816 : result = list_concat(result, indexpaths);
1246 : }
1247 :
1248 13416 : return result;
1249 : }
1250 :
1251 : /*
1252 : * generate_bitmap_or_paths
1253 : * Look through the list of clauses to find OR clauses, and generate
1254 : * a BitmapOrPath for each one we can handle that way. Return a list
1255 : * of the generated BitmapOrPaths.
1256 : *
1257 : * other_clauses is a list of additional clauses that can be assumed true
1258 : * for the purpose of generating indexquals, but are not to be searched for
1259 : * ORs. (See build_paths_for_OR() for motivation.)
1260 : */
1261 : static List *
1262 359104 : generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel,
1263 : List *clauses, List *other_clauses)
1264 : {
1265 359104 : List *result = NIL;
1266 : List *all_clauses;
1267 : ListCell *lc;
1268 :
1269 : /*
1270 : * We can use both the current and other clauses as context for
1271 : * build_paths_for_OR; no need to remove ORs from the lists.
1272 : */
1273 359104 : all_clauses = list_concat(list_copy(clauses), other_clauses);
1274 :
1275 547098 : foreach(lc, clauses)
1276 : {
1277 187994 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
1278 : List *pathlist;
1279 : Path *bitmapqual;
1280 : ListCell *j;
1281 :
1282 : /* Ignore RestrictInfos that aren't ORs */
1283 187994 : if (!restriction_is_or_clause(rinfo))
1284 175064 : continue;
1285 :
1286 : /*
1287 : * We must be able to match at least one index to each of the arms of
1288 : * the OR, else we can't use it.
1289 : */
1290 12930 : pathlist = NIL;
1291 13734 : foreach(j, ((BoolExpr *) rinfo->orclause)->args)
1292 : {
1293 13416 : Node *orarg = (Node *) lfirst(j);
1294 : List *indlist;
1295 :
1296 : /* OR arguments should be ANDs or sub-RestrictInfos */
1297 13416 : if (is_andclause(orarg))
1298 : {
1299 504 : List *andargs = ((BoolExpr *) orarg)->args;
1300 :
1301 504 : indlist = build_paths_for_OR(root, rel,
1302 : andargs,
1303 : all_clauses);
1304 :
1305 : /* Recurse in case there are sub-ORs */
1306 504 : indlist = list_concat(indlist,
1307 : generate_bitmap_or_paths(root, rel,
1308 : andargs,
1309 : all_clauses));
1310 : }
1311 : else
1312 : {
1313 12912 : RestrictInfo *rinfo = castNode(RestrictInfo, orarg);
1314 : List *orargs;
1315 :
1316 : Assert(!restriction_is_or_clause(rinfo));
1317 12912 : orargs = list_make1(rinfo);
1318 :
1319 12912 : indlist = build_paths_for_OR(root, rel,
1320 : orargs,
1321 : all_clauses);
1322 : }
1323 :
1324 : /*
1325 : * If nothing matched this arm, we can't do anything with this OR
1326 : * clause.
1327 : */
1328 13416 : if (indlist == NIL)
1329 : {
1330 12612 : pathlist = NIL;
1331 12612 : break;
1332 : }
1333 :
1334 : /*
1335 : * OK, pick the most promising AND combination, and add it to
1336 : * pathlist.
1337 : */
1338 804 : bitmapqual = choose_bitmap_and(root, rel, indlist);
1339 804 : pathlist = lappend(pathlist, bitmapqual);
1340 : }
1341 :
1342 : /*
1343 : * If we have a match for every arm, then turn them into a
1344 : * BitmapOrPath, and add to result list.
1345 : */
1346 12930 : if (pathlist != NIL)
1347 : {
1348 318 : bitmapqual = (Path *) create_bitmap_or_path(root, rel, pathlist);
1349 318 : result = lappend(result, bitmapqual);
1350 : }
1351 : }
1352 :
1353 359104 : return result;
1354 : }
1355 :
1356 :
1357 : /*
1358 : * choose_bitmap_and
1359 : * Given a nonempty list of bitmap paths, AND them into one path.
1360 : *
1361 : * This is a nontrivial decision since we can legally use any subset of the
1362 : * given path set. We want to choose a good tradeoff between selectivity
1363 : * and cost of computing the bitmap.
1364 : *
1365 : * The result is either a single one of the inputs, or a BitmapAndPath
1366 : * combining multiple inputs.
1367 : */
1368 : static Path *
1369 173072 : choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel, List *paths)
1370 : {
1371 173072 : int npaths = list_length(paths);
1372 : PathClauseUsage **pathinfoarray;
1373 : PathClauseUsage *pathinfo;
1374 : List *clauselist;
1375 173072 : List *bestpaths = NIL;
1376 173072 : Cost bestcost = 0;
1377 : int i,
1378 : j;
1379 : ListCell *l;
1380 :
1381 : Assert(npaths > 0); /* else caller error */
1382 173072 : if (npaths == 1)
1383 137596 : return (Path *) linitial(paths); /* easy case */
1384 :
1385 : /*
1386 : * In theory we should consider every nonempty subset of the given paths.
1387 : * In practice that seems like overkill, given the crude nature of the
1388 : * estimates, not to mention the possible effects of higher-level AND and
1389 : * OR clauses. Moreover, it's completely impractical if there are a large
1390 : * number of paths, since the work would grow as O(2^N).
1391 : *
1392 : * As a heuristic, we first check for paths using exactly the same sets of
1393 : * WHERE clauses + index predicate conditions, and reject all but the
1394 : * cheapest-to-scan in any such group. This primarily gets rid of indexes
1395 : * that include the interesting columns but also irrelevant columns. (In
1396 : * situations where the DBA has gone overboard on creating variant
1397 : * indexes, this can make for a very large reduction in the number of
1398 : * paths considered further.)
1399 : *
1400 : * We then sort the surviving paths with the cheapest-to-scan first, and
1401 : * for each path, consider using that path alone as the basis for a bitmap
1402 : * scan. Then we consider bitmap AND scans formed from that path plus
1403 : * each subsequent (higher-cost) path, adding on a subsequent path if it
1404 : * results in a reduction in the estimated total scan cost. This means we
1405 : * consider about O(N^2) rather than O(2^N) path combinations, which is
1406 : * quite tolerable, especially given than N is usually reasonably small
1407 : * because of the prefiltering step. The cheapest of these is returned.
1408 : *
1409 : * We will only consider AND combinations in which no two indexes use the
1410 : * same WHERE clause. This is a bit of a kluge: it's needed because
1411 : * costsize.c and clausesel.c aren't very smart about redundant clauses.
1412 : * They will usually double-count the redundant clauses, producing a
1413 : * too-small selectivity that makes a redundant AND step look like it
1414 : * reduces the total cost. Perhaps someday that code will be smarter and
1415 : * we can remove this limitation. (But note that this also defends
1416 : * against flat-out duplicate input paths, which can happen because
1417 : * match_join_clauses_to_index will find the same OR join clauses that
1418 : * extract_restriction_or_clauses has pulled OR restriction clauses out
1419 : * of.)
1420 : *
1421 : * For the same reason, we reject AND combinations in which an index
1422 : * predicate clause duplicates another clause. Here we find it necessary
1423 : * to be even stricter: we'll reject a partial index if any of its
1424 : * predicate clauses are implied by the set of WHERE clauses and predicate
1425 : * clauses used so far. This covers cases such as a condition "x = 42"
1426 : * used with a plain index, followed by a clauseless scan of a partial
1427 : * index "WHERE x >= 40 AND x < 50". The partial index has been accepted
1428 : * only because "x = 42" was present, and so allowing it would partially
1429 : * double-count selectivity. (We could use predicate_implied_by on
1430 : * regular qual clauses too, to have a more intelligent, but much more
1431 : * expensive, check for redundancy --- but in most cases simple equality
1432 : * seems to suffice.)
1433 : */
1434 :
1435 : /*
1436 : * Extract clause usage info and detect any paths that use exactly the
1437 : * same set of clauses; keep only the cheapest-to-scan of any such groups.
1438 : * The surviving paths are put into an array for qsort'ing.
1439 : */
1440 35476 : pathinfoarray = (PathClauseUsage **)
1441 35476 : palloc(npaths * sizeof(PathClauseUsage *));
1442 35476 : clauselist = NIL;
1443 35476 : npaths = 0;
1444 109606 : foreach(l, paths)
1445 : {
1446 74130 : Path *ipath = (Path *) lfirst(l);
1447 :
1448 74130 : pathinfo = classify_index_clause_usage(ipath, &clauselist);
1449 :
1450 : /* If it's unclassifiable, treat it as distinct from all others */
1451 74130 : if (pathinfo->unclassifiable)
1452 : {
1453 0 : pathinfoarray[npaths++] = pathinfo;
1454 0 : continue;
1455 : }
1456 :
1457 108178 : for (i = 0; i < npaths; i++)
1458 : {
1459 83600 : if (!pathinfoarray[i]->unclassifiable &&
1460 41800 : bms_equal(pathinfo->clauseids, pathinfoarray[i]->clauseids))
1461 7752 : break;
1462 : }
1463 74130 : if (i < npaths)
1464 : {
1465 : /* duplicate clauseids, keep the cheaper one */
1466 : Cost ncost;
1467 : Cost ocost;
1468 : Selectivity nselec;
1469 : Selectivity oselec;
1470 :
1471 7752 : cost_bitmap_tree_node(pathinfo->path, &ncost, &nselec);
1472 7752 : cost_bitmap_tree_node(pathinfoarray[i]->path, &ocost, &oselec);
1473 7752 : if (ncost < ocost)
1474 418 : pathinfoarray[i] = pathinfo;
1475 : }
1476 : else
1477 : {
1478 : /* not duplicate clauseids, add to array */
1479 66378 : pathinfoarray[npaths++] = pathinfo;
1480 : }
1481 : }
1482 :
1483 : /* If only one surviving path, we're done */
1484 35476 : if (npaths == 1)
1485 6186 : return pathinfoarray[0]->path;
1486 :
1487 : /* Sort the surviving paths by index access cost */
1488 29290 : qsort(pathinfoarray, npaths, sizeof(PathClauseUsage *),
1489 : path_usage_comparator);
1490 :
1491 : /*
1492 : * For each surviving index, consider it as an "AND group leader", and see
1493 : * whether adding on any of the later indexes results in an AND path with
1494 : * cheaper total cost than before. Then take the cheapest AND group.
1495 : *
1496 : * Note: paths that are either clauseless or unclassifiable will have
1497 : * empty clauseids, so that they will not be rejected by the clauseids
1498 : * filter here, nor will they cause later paths to be rejected by it.
1499 : */
1500 89482 : for (i = 0; i < npaths; i++)
1501 : {
1502 : Cost costsofar;
1503 : List *qualsofar;
1504 : Bitmapset *clauseidsofar;
1505 : ListCell *lastcell;
1506 :
1507 60192 : pathinfo = pathinfoarray[i];
1508 60192 : paths = list_make1(pathinfo->path);
1509 60192 : costsofar = bitmap_scan_cost_est(root, rel, pathinfo->path);
1510 60192 : qualsofar = list_concat(list_copy(pathinfo->quals),
1511 60192 : list_copy(pathinfo->preds));
1512 60192 : clauseidsofar = bms_copy(pathinfo->clauseids);
1513 60192 : lastcell = list_head(paths); /* for quick deletions */
1514 :
1515 92962 : for (j = i + 1; j < npaths; j++)
1516 : {
1517 : Cost newcost;
1518 :
1519 32770 : pathinfo = pathinfoarray[j];
1520 : /* Check for redundancy */
1521 32770 : if (bms_overlap(pathinfo->clauseids, clauseidsofar))
1522 21692 : continue; /* consider it redundant */
1523 11078 : if (pathinfo->preds)
1524 : {
1525 8 : bool redundant = false;
1526 :
1527 : /* we check each predicate clause separately */
1528 8 : foreach(l, pathinfo->preds)
1529 : {
1530 8 : Node *np = (Node *) lfirst(l);
1531 :
1532 8 : if (predicate_implied_by(list_make1(np), qualsofar, false))
1533 : {
1534 8 : redundant = true;
1535 8 : break; /* out of inner foreach loop */
1536 : }
1537 : }
1538 8 : if (redundant)
1539 8 : continue;
1540 : }
1541 : /* tentatively add new path to paths, so we can estimate cost */
1542 11070 : paths = lappend(paths, pathinfo->path);
1543 11070 : newcost = bitmap_and_cost_est(root, rel, paths);
1544 11070 : if (newcost < costsofar)
1545 : {
1546 : /* keep new path in paths, update subsidiary variables */
1547 340 : costsofar = newcost;
1548 340 : qualsofar = list_concat(qualsofar,
1549 340 : list_copy(pathinfo->quals));
1550 340 : qualsofar = list_concat(qualsofar,
1551 340 : list_copy(pathinfo->preds));
1552 340 : clauseidsofar = bms_add_members(clauseidsofar,
1553 340 : pathinfo->clauseids);
1554 340 : lastcell = lnext(lastcell);
1555 : }
1556 : else
1557 : {
1558 : /* reject new path, remove it from paths list */
1559 10730 : paths = list_delete_cell(paths, lnext(lastcell), lastcell);
1560 : }
1561 : Assert(lnext(lastcell) == NULL);
1562 : }
1563 :
1564 : /* Keep the cheapest AND-group (or singleton) */
1565 60192 : if (i == 0 || costsofar < bestcost)
1566 : {
1567 30308 : bestpaths = paths;
1568 30308 : bestcost = costsofar;
1569 : }
1570 :
1571 : /* some easy cleanup (we don't try real hard though) */
1572 60192 : list_free(qualsofar);
1573 : }
1574 :
1575 29290 : if (list_length(bestpaths) == 1)
1576 29242 : return (Path *) linitial(bestpaths); /* no need for AND */
1577 48 : return (Path *) create_bitmap_and_path(root, rel, bestpaths);
1578 : }
1579 :
1580 : /* qsort comparator to sort in increasing index access cost order */
1581 : static int
1582 31736 : path_usage_comparator(const void *a, const void *b)
1583 : {
1584 31736 : PathClauseUsage *pa = *(PathClauseUsage *const *) a;
1585 31736 : PathClauseUsage *pb = *(PathClauseUsage *const *) b;
1586 : Cost acost;
1587 : Cost bcost;
1588 : Selectivity aselec;
1589 : Selectivity bselec;
1590 :
1591 31736 : cost_bitmap_tree_node(pa->path, &acost, &aselec);
1592 31736 : cost_bitmap_tree_node(pb->path, &bcost, &bselec);
1593 :
1594 : /*
1595 : * If costs are the same, sort by selectivity.
1596 : */
1597 31736 : if (acost < bcost)
1598 22570 : return -1;
1599 9166 : if (acost > bcost)
1600 6374 : return 1;
1601 :
1602 2792 : if (aselec < bselec)
1603 2134 : return -1;
1604 658 : if (aselec > bselec)
1605 154 : return 1;
1606 :
1607 504 : return 0;
1608 : }
1609 :
1610 : /*
1611 : * Estimate the cost of actually executing a bitmap scan with a single
1612 : * index path (no BitmapAnd, at least not at this level; but it could be
1613 : * a BitmapOr).
1614 : */
1615 : static Cost
1616 60192 : bitmap_scan_cost_est(PlannerInfo *root, RelOptInfo *rel, Path *ipath)
1617 : {
1618 : BitmapHeapPath bpath;
1619 : Relids required_outer;
1620 :
1621 : /* Identify required outer rels, in case it's a parameterized scan */
1622 60192 : required_outer = get_bitmap_tree_required_outer(ipath);
1623 :
1624 : /* Set up a dummy BitmapHeapPath */
1625 60192 : bpath.path.type = T_BitmapHeapPath;
1626 60192 : bpath.path.pathtype = T_BitmapHeapScan;
1627 60192 : bpath.path.parent = rel;
1628 60192 : bpath.path.pathtarget = rel->reltarget;
1629 60192 : bpath.path.param_info = get_baserel_parampathinfo(root, rel,
1630 : required_outer);
1631 60192 : bpath.path.pathkeys = NIL;
1632 60192 : bpath.bitmapqual = ipath;
1633 :
1634 : /*
1635 : * Check the cost of temporary path without considering parallelism.
1636 : * Parallel bitmap heap path will be considered at later stage.
1637 : */
1638 60192 : bpath.path.parallel_workers = 0;
1639 60192 : cost_bitmap_heap_scan(&bpath.path, root, rel,
1640 : bpath.path.param_info,
1641 : ipath,
1642 : get_loop_count(root, rel->relid, required_outer));
1643 :
1644 60192 : return bpath.path.total_cost;
1645 : }
1646 :
1647 : /*
1648 : * Estimate the cost of actually executing a BitmapAnd scan with the given
1649 : * inputs.
1650 : */
1651 : static Cost
1652 11070 : bitmap_and_cost_est(PlannerInfo *root, RelOptInfo *rel, List *paths)
1653 : {
1654 : BitmapAndPath apath;
1655 : BitmapHeapPath bpath;
1656 : Relids required_outer;
1657 :
1658 : /* Set up a dummy BitmapAndPath */
1659 11070 : apath.path.type = T_BitmapAndPath;
1660 11070 : apath.path.pathtype = T_BitmapAnd;
1661 11070 : apath.path.parent = rel;
1662 11070 : apath.path.pathtarget = rel->reltarget;
1663 11070 : apath.path.param_info = NULL; /* not used in bitmap trees */
1664 11070 : apath.path.pathkeys = NIL;
1665 11070 : apath.bitmapquals = paths;
1666 11070 : cost_bitmap_and_node(&apath, root);
1667 :
1668 : /* Identify required outer rels, in case it's a parameterized scan */
1669 11070 : required_outer = get_bitmap_tree_required_outer((Path *) &apath);
1670 :
1671 : /* Set up a dummy BitmapHeapPath */
1672 11070 : bpath.path.type = T_BitmapHeapPath;
1673 11070 : bpath.path.pathtype = T_BitmapHeapScan;
1674 11070 : bpath.path.parent = rel;
1675 11070 : bpath.path.pathtarget = rel->reltarget;
1676 11070 : bpath.path.param_info = get_baserel_parampathinfo(root, rel,
1677 : required_outer);
1678 11070 : bpath.path.pathkeys = NIL;
1679 11070 : bpath.bitmapqual = (Path *) &apath;
1680 :
1681 : /*
1682 : * Check the cost of temporary path without considering parallelism.
1683 : * Parallel bitmap heap path will be considered at later stage.
1684 : */
1685 11070 : bpath.path.parallel_workers = 0;
1686 :
1687 : /* Now we can do cost_bitmap_heap_scan */
1688 11070 : cost_bitmap_heap_scan(&bpath.path, root, rel,
1689 : bpath.path.param_info,
1690 : (Path *) &apath,
1691 : get_loop_count(root, rel->relid, required_outer));
1692 :
1693 11070 : return bpath.path.total_cost;
1694 : }
1695 :
1696 :
1697 : /*
1698 : * classify_index_clause_usage
1699 : * Construct a PathClauseUsage struct describing the WHERE clauses and
1700 : * index predicate clauses used by the given indexscan path.
1701 : * We consider two clauses the same if they are equal().
1702 : *
1703 : * At some point we might want to migrate this info into the Path data
1704 : * structure proper, but for the moment it's only needed within
1705 : * choose_bitmap_and().
1706 : *
1707 : * *clauselist is used and expanded as needed to identify all the distinct
1708 : * clauses seen across successive calls. Caller must initialize it to NIL
1709 : * before first call of a set.
1710 : */
1711 : static PathClauseUsage *
1712 74130 : classify_index_clause_usage(Path *path, List **clauselist)
1713 : {
1714 : PathClauseUsage *result;
1715 : Bitmapset *clauseids;
1716 : ListCell *lc;
1717 :
1718 74130 : result = (PathClauseUsage *) palloc(sizeof(PathClauseUsage));
1719 74130 : result->path = path;
1720 :
1721 : /* Recursively find the quals and preds used by the path */
1722 74130 : result->quals = NIL;
1723 74130 : result->preds = NIL;
1724 74130 : find_indexpath_quals(path, &result->quals, &result->preds);
1725 :
1726 : /*
1727 : * Some machine-generated queries have outlandish numbers of qual clauses.
1728 : * To avoid getting into O(N^2) behavior even in this preliminary
1729 : * classification step, we want to limit the number of entries we can
1730 : * accumulate in *clauselist. Treat any path with more than 100 quals +
1731 : * preds as unclassifiable, which will cause calling code to consider it
1732 : * distinct from all other paths.
1733 : */
1734 74130 : if (list_length(result->quals) + list_length(result->preds) > 100)
1735 : {
1736 0 : result->clauseids = NULL;
1737 0 : result->unclassifiable = true;
1738 0 : return result;
1739 : }
1740 :
1741 : /* Build up a bitmapset representing the quals and preds */
1742 74130 : clauseids = NULL;
1743 176490 : foreach(lc, result->quals)
1744 : {
1745 102360 : Node *node = (Node *) lfirst(lc);
1746 :
1747 102360 : clauseids = bms_add_member(clauseids,
1748 : find_list_position(node, clauselist));
1749 : }
1750 74242 : foreach(lc, result->preds)
1751 : {
1752 112 : Node *node = (Node *) lfirst(lc);
1753 :
1754 112 : clauseids = bms_add_member(clauseids,
1755 : find_list_position(node, clauselist));
1756 : }
1757 74130 : result->clauseids = clauseids;
1758 74130 : result->unclassifiable = false;
1759 :
1760 74130 : return result;
1761 : }
1762 :
1763 :
1764 : /*
1765 : * get_bitmap_tree_required_outer
1766 : * Find the required outer rels for a bitmap tree (index/and/or)
1767 : *
1768 : * We don't associate any particular parameterization with a BitmapAnd or
1769 : * BitmapOr node; however, the IndexPaths have parameterization info, in
1770 : * their capacity as standalone access paths. The parameterization required
1771 : * for the bitmap heap scan node is the union of rels referenced in the
1772 : * child IndexPaths.
1773 : */
1774 : static Relids
1775 211028 : get_bitmap_tree_required_outer(Path *bitmapqual)
1776 : {
1777 211028 : Relids result = NULL;
1778 : ListCell *lc;
1779 :
1780 211028 : if (IsA(bitmapqual, IndexPath))
1781 : {
1782 199540 : return bms_copy(PATH_REQ_OUTER(bitmapqual));
1783 : }
1784 11488 : else if (IsA(bitmapqual, BitmapAndPath))
1785 : {
1786 33222 : foreach(lc, ((BitmapAndPath *) bitmapqual)->bitmapquals)
1787 : {
1788 22148 : result = bms_join(result,
1789 22148 : get_bitmap_tree_required_outer((Path *) lfirst(lc)));
1790 : }
1791 : }
1792 414 : else if (IsA(bitmapqual, BitmapOrPath))
1793 : {
1794 1270 : foreach(lc, ((BitmapOrPath *) bitmapqual)->bitmapquals)
1795 : {
1796 856 : result = bms_join(result,
1797 856 : get_bitmap_tree_required_outer((Path *) lfirst(lc)));
1798 : }
1799 : }
1800 : else
1801 0 : elog(ERROR, "unrecognized node type: %d", nodeTag(bitmapqual));
1802 :
1803 11488 : return result;
1804 : }
1805 :
1806 :
1807 : /*
1808 : * find_indexpath_quals
1809 : *
1810 : * Given the Path structure for a plain or bitmap indexscan, extract lists
1811 : * of all the index clauses and index predicate conditions used in the Path.
1812 : * These are appended to the initial contents of *quals and *preds (hence
1813 : * caller should initialize those to NIL).
1814 : *
1815 : * Note we are not trying to produce an accurate representation of the AND/OR
1816 : * semantics of the Path, but just find out all the base conditions used.
1817 : *
1818 : * The result lists contain pointers to the expressions used in the Path,
1819 : * but all the list cells are freshly built, so it's safe to destructively
1820 : * modify the lists (eg, by concat'ing with other lists).
1821 : */
1822 : static void
1823 74986 : find_indexpath_quals(Path *bitmapqual, List **quals, List **preds)
1824 : {
1825 74986 : if (IsA(bitmapqual, BitmapAndPath))
1826 : {
1827 0 : BitmapAndPath *apath = (BitmapAndPath *) bitmapqual;
1828 : ListCell *l;
1829 :
1830 0 : foreach(l, apath->bitmapquals)
1831 : {
1832 0 : find_indexpath_quals((Path *) lfirst(l), quals, preds);
1833 : }
1834 : }
1835 74986 : else if (IsA(bitmapqual, BitmapOrPath))
1836 : {
1837 414 : BitmapOrPath *opath = (BitmapOrPath *) bitmapqual;
1838 : ListCell *l;
1839 :
1840 1270 : foreach(l, opath->bitmapquals)
1841 : {
1842 856 : find_indexpath_quals((Path *) lfirst(l), quals, preds);
1843 : }
1844 : }
1845 74572 : else if (IsA(bitmapqual, IndexPath))
1846 : {
1847 74572 : IndexPath *ipath = (IndexPath *) bitmapqual;
1848 : ListCell *l;
1849 :
1850 176932 : foreach(l, ipath->indexclauses)
1851 : {
1852 102360 : IndexClause *iclause = (IndexClause *) lfirst(l);
1853 :
1854 102360 : *quals = lappend(*quals, iclause->rinfo->clause);
1855 : }
1856 74572 : *preds = list_concat(*preds, list_copy(ipath->indexinfo->indpred));
1857 : }
1858 : else
1859 0 : elog(ERROR, "unrecognized node type: %d", nodeTag(bitmapqual));
1860 74986 : }
1861 :
1862 :
1863 : /*
1864 : * find_list_position
1865 : * Return the given node's position (counting from 0) in the given
1866 : * list of nodes. If it's not equal() to any existing list member,
1867 : * add it at the end, and return that position.
1868 : */
1869 : static int
1870 102472 : find_list_position(Node *node, List **nodelist)
1871 : {
1872 : int i;
1873 : ListCell *lc;
1874 :
1875 102472 : i = 0;
1876 156458 : foreach(lc, *nodelist)
1877 : {
1878 85898 : Node *oldnode = (Node *) lfirst(lc);
1879 :
1880 85898 : if (equal(node, oldnode))
1881 31912 : return i;
1882 53986 : i++;
1883 : }
1884 :
1885 70560 : *nodelist = lappend(*nodelist, node);
1886 :
1887 70560 : return i;
1888 : }
1889 :
1890 :
1891 : /*
1892 : * check_index_only
1893 : * Determine whether an index-only scan is possible for this index.
1894 : */
1895 : static bool
1896 433252 : check_index_only(RelOptInfo *rel, IndexOptInfo *index)
1897 : {
1898 : bool result;
1899 433252 : Bitmapset *attrs_used = NULL;
1900 433252 : Bitmapset *index_canreturn_attrs = NULL;
1901 433252 : Bitmapset *index_cannotreturn_attrs = NULL;
1902 : ListCell *lc;
1903 : int i;
1904 :
1905 : /* Index-only scans must be enabled */
1906 433252 : if (!enable_indexonlyscan)
1907 1776 : return false;
1908 :
1909 : /*
1910 : * Check that all needed attributes of the relation are available from the
1911 : * index.
1912 : */
1913 :
1914 : /*
1915 : * First, identify all the attributes needed for joins or final output.
1916 : * Note: we must look at rel's targetlist, not the attr_needed data,
1917 : * because attr_needed isn't computed for inheritance child rels.
1918 : */
1919 431476 : pull_varattnos((Node *) rel->reltarget->exprs, rel->relid, &attrs_used);
1920 :
1921 : /*
1922 : * Add all the attributes used by restriction clauses; but consider only
1923 : * those clauses not implied by the index predicate, since ones that are
1924 : * so implied don't need to be checked explicitly in the plan.
1925 : *
1926 : * Note: attributes used only in index quals would not be needed at
1927 : * runtime either, if we are certain that the index is not lossy. However
1928 : * it'd be complicated to account for that accurately, and it doesn't
1929 : * matter in most cases, since we'd conclude that such attributes are
1930 : * available from the index anyway.
1931 : */
1932 844840 : foreach(lc, index->indrestrictinfo)
1933 : {
1934 413364 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
1935 :
1936 413364 : pull_varattnos((Node *) rinfo->clause, rel->relid, &attrs_used);
1937 : }
1938 :
1939 : /*
1940 : * Construct a bitmapset of columns that the index can return back in an
1941 : * index-only scan. If there are multiple index columns containing the
1942 : * same attribute, all of them must be capable of returning the value,
1943 : * since we might recheck operators on any of them. (Potentially we could
1944 : * be smarter about that, but it's such a weird situation that it doesn't
1945 : * seem worth spending a lot of sweat on.)
1946 : */
1947 1199314 : for (i = 0; i < index->ncolumns; i++)
1948 : {
1949 767838 : int attno = index->indexkeys[i];
1950 :
1951 : /*
1952 : * For the moment, we just ignore index expressions. It might be nice
1953 : * to do something with them, later.
1954 : */
1955 767838 : if (attno == 0)
1956 1694 : continue;
1957 :
1958 766144 : if (index->canreturn[i])
1959 644678 : index_canreturn_attrs =
1960 644678 : bms_add_member(index_canreturn_attrs,
1961 : attno - FirstLowInvalidHeapAttributeNumber);
1962 : else
1963 121466 : index_cannotreturn_attrs =
1964 121466 : bms_add_member(index_cannotreturn_attrs,
1965 : attno - FirstLowInvalidHeapAttributeNumber);
1966 : }
1967 :
1968 431476 : index_canreturn_attrs = bms_del_members(index_canreturn_attrs,
1969 : index_cannotreturn_attrs);
1970 :
1971 : /* Do we have all the necessary attributes? */
1972 431476 : result = bms_is_subset(attrs_used, index_canreturn_attrs);
1973 :
1974 431476 : bms_free(attrs_used);
1975 431476 : bms_free(index_canreturn_attrs);
1976 431476 : bms_free(index_cannotreturn_attrs);
1977 :
1978 431476 : return result;
1979 : }
1980 :
1981 : /*
1982 : * get_loop_count
1983 : * Choose the loop count estimate to use for costing a parameterized path
1984 : * with the given set of outer relids.
1985 : *
1986 : * Since we produce parameterized paths before we've begun to generate join
1987 : * relations, it's impossible to predict exactly how many times a parameterized
1988 : * path will be iterated; we don't know the size of the relation that will be
1989 : * on the outside of the nestloop. However, we should try to account for
1990 : * multiple iterations somehow in costing the path. The heuristic embodied
1991 : * here is to use the rowcount of the smallest other base relation needed in
1992 : * the join clauses used by the path. (We could alternatively consider the
1993 : * largest one, but that seems too optimistic.) This is of course the right
1994 : * answer for single-other-relation cases, and it seems like a reasonable
1995 : * zero-order approximation for multiway-join cases.
1996 : *
1997 : * In addition, we check to see if the other side of each join clause is on
1998 : * the inside of some semijoin that the current relation is on the outside of.
1999 : * If so, the only way that a parameterized path could be used is if the
2000 : * semijoin RHS has been unique-ified, so we should use the number of unique
2001 : * RHS rows rather than using the relation's raw rowcount.
2002 : *
2003 : * Note: for this to work, allpaths.c must establish all baserel size
2004 : * estimates before it begins to compute paths, or at least before it
2005 : * calls create_index_paths().
2006 : */
2007 : static double
2008 563050 : get_loop_count(PlannerInfo *root, Index cur_relid, Relids outer_relids)
2009 : {
2010 : double result;
2011 : int outer_relid;
2012 :
2013 : /* For a non-parameterized path, just return 1.0 quickly */
2014 563050 : if (outer_relids == NULL)
2015 421472 : return 1.0;
2016 :
2017 141578 : result = 0.0;
2018 141578 : outer_relid = -1;
2019 425476 : while ((outer_relid = bms_next_member(outer_relids, outer_relid)) >= 0)
2020 : {
2021 : RelOptInfo *outer_rel;
2022 : double rowcount;
2023 :
2024 : /* Paranoia: ignore bogus relid indexes */
2025 142320 : if (outer_relid >= root->simple_rel_array_size)
2026 0 : continue;
2027 142320 : outer_rel = root->simple_rel_array[outer_relid];
2028 142320 : if (outer_rel == NULL)
2029 0 : continue;
2030 : Assert(outer_rel->relid == outer_relid); /* sanity check on array */
2031 :
2032 : /* Other relation could be proven empty, if so ignore */
2033 142320 : if (IS_DUMMY_REL(outer_rel))
2034 16 : continue;
2035 :
2036 : /* Otherwise, rel's rows estimate should be valid by now */
2037 : Assert(outer_rel->rows > 0);
2038 :
2039 : /* Check to see if rel is on the inside of any semijoins */
2040 142304 : rowcount = adjust_rowcount_for_semijoins(root,
2041 : cur_relid,
2042 : outer_relid,
2043 : outer_rel->rows);
2044 :
2045 : /* Remember smallest row count estimate among the outer rels */
2046 142304 : if (result == 0.0 || result > rowcount)
2047 141846 : result = rowcount;
2048 : }
2049 : /* Return 1.0 if we found no valid relations (shouldn't happen) */
2050 141578 : return (result > 0.0) ? result : 1.0;
2051 : }
2052 :
2053 : /*
2054 : * Check to see if outer_relid is on the inside of any semijoin that cur_relid
2055 : * is on the outside of. If so, replace rowcount with the estimated number of
2056 : * unique rows from the semijoin RHS (assuming that's smaller, which it might
2057 : * not be). The estimate is crude but it's the best we can do at this stage
2058 : * of the proceedings.
2059 : */
2060 : static double
2061 142304 : adjust_rowcount_for_semijoins(PlannerInfo *root,
2062 : Index cur_relid,
2063 : Index outer_relid,
2064 : double rowcount)
2065 : {
2066 : ListCell *lc;
2067 :
2068 256640 : foreach(lc, root->join_info_list)
2069 : {
2070 114336 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(lc);
2071 :
2072 116448 : if (sjinfo->jointype == JOIN_SEMI &&
2073 2416 : bms_is_member(cur_relid, sjinfo->syn_lefthand) &&
2074 304 : bms_is_member(outer_relid, sjinfo->syn_righthand))
2075 : {
2076 : /* Estimate number of unique-ified rows */
2077 : double nraw;
2078 : double nunique;
2079 :
2080 248 : nraw = approximate_joinrel_size(root, sjinfo->syn_righthand);
2081 248 : nunique = estimate_num_groups(root,
2082 : sjinfo->semi_rhs_exprs,
2083 : nraw,
2084 : NULL);
2085 248 : if (rowcount > nunique)
2086 116 : rowcount = nunique;
2087 : }
2088 : }
2089 142304 : return rowcount;
2090 : }
2091 :
2092 : /*
2093 : * Make an approximate estimate of the size of a joinrel.
2094 : *
2095 : * We don't have enough info at this point to get a good estimate, so we
2096 : * just multiply the base relation sizes together. Fortunately, this is
2097 : * the right answer anyway for the most common case with a single relation
2098 : * on the RHS of a semijoin. Also, estimate_num_groups() has only a weak
2099 : * dependency on its input_rows argument (it basically uses it as a clamp).
2100 : * So we might be able to get a fairly decent end result even with a severe
2101 : * overestimate of the RHS's raw size.
2102 : */
2103 : static double
2104 248 : approximate_joinrel_size(PlannerInfo *root, Relids relids)
2105 : {
2106 248 : double rowcount = 1.0;
2107 : int relid;
2108 :
2109 248 : relid = -1;
2110 792 : while ((relid = bms_next_member(relids, relid)) >= 0)
2111 : {
2112 : RelOptInfo *rel;
2113 :
2114 : /* Paranoia: ignore bogus relid indexes */
2115 296 : if (relid >= root->simple_rel_array_size)
2116 0 : continue;
2117 296 : rel = root->simple_rel_array[relid];
2118 296 : if (rel == NULL)
2119 0 : continue;
2120 : Assert(rel->relid == relid); /* sanity check on array */
2121 :
2122 : /* Relation could be proven empty, if so ignore */
2123 296 : if (IS_DUMMY_REL(rel))
2124 0 : continue;
2125 :
2126 : /* Otherwise, rel's rows estimate should be valid by now */
2127 : Assert(rel->rows > 0);
2128 :
2129 : /* Accumulate product */
2130 296 : rowcount *= rel->rows;
2131 : }
2132 248 : return rowcount;
2133 : }
2134 :
2135 :
2136 : /****************************************************************************
2137 : * ---- ROUTINES TO CHECK QUERY CLAUSES ----
2138 : ****************************************************************************/
2139 :
2140 : /*
2141 : * match_restriction_clauses_to_index
2142 : * Identify restriction clauses for the rel that match the index.
2143 : * Matching clauses are added to *clauseset.
2144 : */
2145 : static void
2146 374408 : match_restriction_clauses_to_index(PlannerInfo *root,
2147 : IndexOptInfo *index,
2148 : IndexClauseSet *clauseset)
2149 : {
2150 : /* We can ignore clauses that are implied by the index predicate */
2151 374408 : match_clauses_to_index(root, index->indrestrictinfo, index, clauseset);
2152 374408 : }
2153 :
2154 : /*
2155 : * match_join_clauses_to_index
2156 : * Identify join clauses for the rel that match the index.
2157 : * Matching clauses are added to *clauseset.
2158 : * Also, add any potentially usable join OR clauses to *joinorclauses.
2159 : */
2160 : static void
2161 374408 : match_join_clauses_to_index(PlannerInfo *root,
2162 : RelOptInfo *rel, IndexOptInfo *index,
2163 : IndexClauseSet *clauseset,
2164 : List **joinorclauses)
2165 : {
2166 : ListCell *lc;
2167 :
2168 : /* Scan the rel's join clauses */
2169 521858 : foreach(lc, rel->joininfo)
2170 : {
2171 147450 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
2172 :
2173 : /* Check if clause can be moved to this rel */
2174 147450 : if (!join_clause_is_movable_to(rinfo, rel))
2175 73386 : continue;
2176 :
2177 : /* Potentially usable, so see if it matches the index or is an OR */
2178 74064 : if (restriction_is_or_clause(rinfo))
2179 11918 : *joinorclauses = lappend(*joinorclauses, rinfo);
2180 : else
2181 62146 : match_clause_to_index(root, rinfo, index, clauseset);
2182 : }
2183 374408 : }
2184 :
2185 : /*
2186 : * match_eclass_clauses_to_index
2187 : * Identify EquivalenceClass join clauses for the rel that match the index.
2188 : * Matching clauses are added to *clauseset.
2189 : */
2190 : static void
2191 374408 : match_eclass_clauses_to_index(PlannerInfo *root, IndexOptInfo *index,
2192 : IndexClauseSet *clauseset)
2193 : {
2194 : int indexcol;
2195 :
2196 : /* No work if rel is not in any such ECs */
2197 374408 : if (!index->rel->has_eclass_joins)
2198 279684 : return;
2199 :
2200 239444 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
2201 : {
2202 : ec_member_matches_arg arg;
2203 : List *clauses;
2204 :
2205 : /* Generate clauses, skipping any that join to lateral_referencers */
2206 144720 : arg.index = index;
2207 144720 : arg.indexcol = indexcol;
2208 144720 : clauses = generate_implied_equalities_for_column(root,
2209 : index->rel,
2210 : ec_member_matches_indexcol,
2211 : (void *) &arg,
2212 144720 : index->rel->lateral_referencers);
2213 :
2214 : /*
2215 : * We have to check whether the results actually do match the index,
2216 : * since for non-btree indexes the EC's equality operators might not
2217 : * be in the index opclass (cf ec_member_matches_indexcol).
2218 : */
2219 144720 : match_clauses_to_index(root, clauses, index, clauseset);
2220 : }
2221 : }
2222 :
2223 : /*
2224 : * match_clauses_to_index
2225 : * Perform match_clause_to_index() for each clause in a list.
2226 : * Matching clauses are added to *clauseset.
2227 : */
2228 : static void
2229 553728 : match_clauses_to_index(PlannerInfo *root,
2230 : List *clauses,
2231 : IndexOptInfo *index,
2232 : IndexClauseSet *clauseset)
2233 : {
2234 : ListCell *lc;
2235 :
2236 1006382 : foreach(lc, clauses)
2237 : {
2238 452654 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
2239 :
2240 452654 : match_clause_to_index(root, rinfo, index, clauseset);
2241 : }
2242 553728 : }
2243 :
2244 : /*
2245 : * match_clause_to_index
2246 : * Test whether a qual clause can be used with an index.
2247 : *
2248 : * If the clause is usable, add an IndexClause entry for it to the appropriate
2249 : * list in *clauseset. (*clauseset must be initialized to zeroes before first
2250 : * call.)
2251 : *
2252 : * Note: in some circumstances we may find the same RestrictInfos coming from
2253 : * multiple places. Defend against redundant outputs by refusing to add a
2254 : * clause twice (pointer equality should be a good enough check for this).
2255 : *
2256 : * Note: it's possible that a badly-defined index could have multiple matching
2257 : * columns. We always select the first match if so; this avoids scenarios
2258 : * wherein we get an inflated idea of the index's selectivity by using the
2259 : * same clause multiple times with different index columns.
2260 : */
2261 : static void
2262 514800 : match_clause_to_index(PlannerInfo *root,
2263 : RestrictInfo *rinfo,
2264 : IndexOptInfo *index,
2265 : IndexClauseSet *clauseset)
2266 : {
2267 : int indexcol;
2268 :
2269 : /*
2270 : * Never match pseudoconstants to indexes. (Normally a match could not
2271 : * happen anyway, since a pseudoconstant clause couldn't contain a Var,
2272 : * but what if someone builds an expression index on a constant? It's not
2273 : * totally unreasonable to do so with a partial index, either.)
2274 : */
2275 514800 : if (rinfo->pseudoconstant)
2276 4648 : return;
2277 :
2278 : /*
2279 : * If clause can't be used as an indexqual because it must wait till after
2280 : * some lower-security-level restriction clause, reject it.
2281 : */
2282 510152 : if (!restriction_is_securely_promotable(rinfo, index->rel))
2283 524 : return;
2284 :
2285 : /* OK, check each index key column for a match */
2286 1082120 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
2287 : {
2288 : IndexClause *iclause;
2289 : ListCell *lc;
2290 :
2291 : /* Ignore duplicates */
2292 809230 : foreach(lc, clauseset->indexclauses[indexcol])
2293 : {
2294 31004 : IndexClause *iclause = (IndexClause *) lfirst(lc);
2295 :
2296 31004 : if (iclause->rinfo == rinfo)
2297 0 : return;
2298 : }
2299 :
2300 : /* OK, try to match the clause to the index column */
2301 778226 : iclause = match_clause_to_indexcol(root,
2302 : rinfo,
2303 : indexcol,
2304 : index);
2305 778226 : if (iclause)
2306 : {
2307 : /* Success, so record it */
2308 205734 : clauseset->indexclauses[indexcol] =
2309 205734 : lappend(clauseset->indexclauses[indexcol], iclause);
2310 205734 : clauseset->nonempty = true;
2311 205734 : return;
2312 : }
2313 : }
2314 : }
2315 :
2316 : /*
2317 : * match_clause_to_indexcol()
2318 : * Determine whether a restriction clause matches a column of an index,
2319 : * and if so, build an IndexClause node describing the details.
2320 : *
2321 : * To match an index normally, an operator clause:
2322 : *
2323 : * (1) must be in the form (indexkey op const) or (const op indexkey);
2324 : * and
2325 : * (2) must contain an operator which is in the index's operator family
2326 : * for this column; and
2327 : * (3) must match the collation of the index, if collation is relevant.
2328 : *
2329 : * Our definition of "const" is exceedingly liberal: we allow anything that
2330 : * doesn't involve a volatile function or a Var of the index's relation.
2331 : * In particular, Vars belonging to other relations of the query are
2332 : * accepted here, since a clause of that form can be used in a
2333 : * parameterized indexscan. It's the responsibility of higher code levels
2334 : * to manage restriction and join clauses appropriately.
2335 : *
2336 : * Note: we do need to check for Vars of the index's relation on the
2337 : * "const" side of the clause, since clauses like (a.f1 OP (b.f2 OP a.f3))
2338 : * are not processable by a parameterized indexscan on a.f1, whereas
2339 : * something like (a.f1 OP (b.f2 OP c.f3)) is.
2340 : *
2341 : * Presently, the executor can only deal with indexquals that have the
2342 : * indexkey on the left, so we can only use clauses that have the indexkey
2343 : * on the right if we can commute the clause to put the key on the left.
2344 : * We handle that by generating an IndexClause with the correctly-commuted
2345 : * opclause as a derived indexqual.
2346 : *
2347 : * If the index has a collation, the clause must have the same collation.
2348 : * For collation-less indexes, we assume it doesn't matter; this is
2349 : * necessary for cases like "hstore ? text", wherein hstore's operators
2350 : * don't care about collation but the clause will get marked with a
2351 : * collation anyway because of the text argument. (This logic is
2352 : * embodied in the macro IndexCollMatchesExprColl.)
2353 : *
2354 : * It is also possible to match RowCompareExpr clauses to indexes (but
2355 : * currently, only btree indexes handle this).
2356 : *
2357 : * It is also possible to match ScalarArrayOpExpr clauses to indexes, when
2358 : * the clause is of the form "indexkey op ANY (arrayconst)".
2359 : *
2360 : * For boolean indexes, it is also possible to match the clause directly
2361 : * to the indexkey; or perhaps the clause is (NOT indexkey).
2362 : *
2363 : * And, last but not least, some operators and functions can be processed
2364 : * to derive (typically lossy) indexquals from a clause that isn't in
2365 : * itself indexable. If we see that any operand of an OpExpr or FuncExpr
2366 : * matches the index key, and the function has a planner support function
2367 : * attached to it, we'll invoke the support function to see if such an
2368 : * indexqual can be built.
2369 : *
2370 : * 'rinfo' is the clause to be tested (as a RestrictInfo node).
2371 : * 'indexcol' is a column number of 'index' (counting from 0).
2372 : * 'index' is the index of interest.
2373 : *
2374 : * Returns an IndexClause if the clause can be used with this index key,
2375 : * or NULL if not.
2376 : *
2377 : * NOTE: returns NULL if clause is an OR or AND clause; it is the
2378 : * responsibility of higher-level routines to cope with those.
2379 : */
2380 : static IndexClause *
2381 778226 : match_clause_to_indexcol(PlannerInfo *root,
2382 : RestrictInfo *rinfo,
2383 : int indexcol,
2384 : IndexOptInfo *index)
2385 : {
2386 : IndexClause *iclause;
2387 778226 : Expr *clause = rinfo->clause;
2388 : Oid opfamily;
2389 :
2390 : Assert(indexcol < index->nkeycolumns);
2391 :
2392 : /*
2393 : * Historically this code has coped with NULL clauses. That's probably
2394 : * not possible anymore, but we might as well continue to cope.
2395 : */
2396 778226 : if (clause == NULL)
2397 0 : return NULL;
2398 :
2399 : /* First check for boolean-index cases. */
2400 778226 : opfamily = index->opfamily[indexcol];
2401 778226 : if (IsBooleanOpfamily(opfamily))
2402 : {
2403 80 : iclause = match_boolean_index_clause(rinfo, indexcol, index);
2404 80 : if (iclause)
2405 52 : return iclause;
2406 : }
2407 :
2408 : /*
2409 : * Clause must be an opclause, funcclause, ScalarArrayOpExpr, or
2410 : * RowCompareExpr. Or, if the index supports it, we can handle IS
2411 : * NULL/NOT NULL clauses.
2412 : */
2413 778174 : if (IsA(clause, OpExpr))
2414 : {
2415 619106 : return match_opclause_to_indexcol(root, rinfo, indexcol, index);
2416 : }
2417 159068 : else if (IsA(clause, FuncExpr))
2418 : {
2419 11072 : return match_funcclause_to_indexcol(root, rinfo, indexcol, index);
2420 : }
2421 147996 : else if (IsA(clause, ScalarArrayOpExpr))
2422 : {
2423 47746 : return match_saopclause_to_indexcol(rinfo, indexcol, index);
2424 : }
2425 100250 : else if (IsA(clause, RowCompareExpr))
2426 : {
2427 192 : return match_rowcompare_to_indexcol(rinfo, indexcol, index);
2428 : }
2429 100058 : else if (index->amsearchnulls && IsA(clause, NullTest))
2430 : {
2431 25024 : NullTest *nt = (NullTest *) clause;
2432 :
2433 50048 : if (!nt->argisrow &&
2434 25024 : match_index_to_operand((Node *) nt->arg, indexcol, index))
2435 : {
2436 906 : iclause = makeNode(IndexClause);
2437 906 : iclause->rinfo = rinfo;
2438 906 : iclause->indexquals = list_make1(rinfo);
2439 906 : iclause->lossy = false;
2440 906 : iclause->indexcol = indexcol;
2441 906 : iclause->indexcols = NIL;
2442 906 : return iclause;
2443 : }
2444 : }
2445 :
2446 99152 : return NULL;
2447 : }
2448 :
2449 : /*
2450 : * match_boolean_index_clause
2451 : * Recognize restriction clauses that can be matched to a boolean index.
2452 : *
2453 : * The idea here is that, for an index on a boolean column that supports the
2454 : * BooleanEqualOperator, we can transform a plain reference to the indexkey
2455 : * into "indexkey = true", or "NOT indexkey" into "indexkey = false", etc,
2456 : * so as to make the expression indexable using the index's "=" operator.
2457 : * Since Postgres 8.1, we must do this because constant simplification does
2458 : * the reverse transformation; without this code there'd be no way to use
2459 : * such an index at all.
2460 : *
2461 : * This should be called only when IsBooleanOpfamily() recognizes the
2462 : * index's operator family. We check to see if the clause matches the
2463 : * index's key, and if so, build a suitable IndexClause.
2464 : */
2465 : static IndexClause *
2466 176 : match_boolean_index_clause(RestrictInfo *rinfo,
2467 : int indexcol,
2468 : IndexOptInfo *index)
2469 : {
2470 176 : Node *clause = (Node *) rinfo->clause;
2471 176 : Expr *op = NULL;
2472 :
2473 : /* Direct match? */
2474 176 : if (match_index_to_operand(clause, indexcol, index))
2475 : {
2476 : /* convert to indexkey = TRUE */
2477 56 : op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2478 : (Expr *) clause,
2479 56 : (Expr *) makeBoolConst(true, false),
2480 : InvalidOid, InvalidOid);
2481 : }
2482 : /* NOT clause? */
2483 120 : else if (is_notclause(clause))
2484 : {
2485 44 : Node *arg = (Node *) get_notclausearg((Expr *) clause);
2486 :
2487 44 : if (match_index_to_operand(arg, indexcol, index))
2488 : {
2489 : /* convert to indexkey = FALSE */
2490 44 : op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2491 : (Expr *) arg,
2492 44 : (Expr *) makeBoolConst(false, false),
2493 : InvalidOid, InvalidOid);
2494 : }
2495 : }
2496 :
2497 : /*
2498 : * Since we only consider clauses at top level of WHERE, we can convert
2499 : * indexkey IS TRUE and indexkey IS FALSE to index searches as well. The
2500 : * different meaning for NULL isn't important.
2501 : */
2502 76 : else if (clause && IsA(clause, BooleanTest))
2503 : {
2504 24 : BooleanTest *btest = (BooleanTest *) clause;
2505 24 : Node *arg = (Node *) btest->arg;
2506 :
2507 36 : if (btest->booltesttype == IS_TRUE &&
2508 12 : match_index_to_operand(arg, indexcol, index))
2509 : {
2510 : /* convert to indexkey = TRUE */
2511 12 : op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2512 : (Expr *) arg,
2513 12 : (Expr *) makeBoolConst(true, false),
2514 : InvalidOid, InvalidOid);
2515 : }
2516 24 : else if (btest->booltesttype == IS_FALSE &&
2517 12 : match_index_to_operand(arg, indexcol, index))
2518 : {
2519 : /* convert to indexkey = FALSE */
2520 12 : op = make_opclause(BooleanEqualOperator, BOOLOID, false,
2521 : (Expr *) arg,
2522 12 : (Expr *) makeBoolConst(false, false),
2523 : InvalidOid, InvalidOid);
2524 : }
2525 : }
2526 :
2527 : /*
2528 : * If we successfully made an operator clause from the given qual, we must
2529 : * wrap it in an IndexClause. It's not lossy.
2530 : */
2531 176 : if (op)
2532 : {
2533 124 : IndexClause *iclause = makeNode(IndexClause);
2534 :
2535 124 : iclause->rinfo = rinfo;
2536 124 : iclause->indexquals = list_make1(make_simple_restrictinfo(op));
2537 124 : iclause->lossy = false;
2538 124 : iclause->indexcol = indexcol;
2539 124 : iclause->indexcols = NIL;
2540 124 : return iclause;
2541 : }
2542 :
2543 52 : return NULL;
2544 : }
2545 :
2546 : /*
2547 : * match_opclause_to_indexcol()
2548 : * Handles the OpExpr case for match_clause_to_indexcol(),
2549 : * which see for comments.
2550 : */
2551 : static IndexClause *
2552 619106 : match_opclause_to_indexcol(PlannerInfo *root,
2553 : RestrictInfo *rinfo,
2554 : int indexcol,
2555 : IndexOptInfo *index)
2556 : {
2557 : IndexClause *iclause;
2558 619106 : OpExpr *clause = (OpExpr *) rinfo->clause;
2559 : Node *leftop,
2560 : *rightop;
2561 : Oid expr_op;
2562 : Oid expr_coll;
2563 : Index index_relid;
2564 : Oid opfamily;
2565 : Oid idxcollation;
2566 :
2567 : /*
2568 : * Only binary operators need apply. (In theory, a planner support
2569 : * function could do something with a unary operator, but it seems
2570 : * unlikely to be worth the cycles to check.)
2571 : */
2572 619106 : if (list_length(clause->args) != 2)
2573 0 : return NULL;
2574 :
2575 619106 : leftop = (Node *) linitial(clause->args);
2576 619106 : rightop = (Node *) lsecond(clause->args);
2577 619106 : expr_op = clause->opno;
2578 619106 : expr_coll = clause->inputcollid;
2579 :
2580 619106 : index_relid = index->rel->relid;
2581 619106 : opfamily = index->opfamily[indexcol];
2582 619106 : idxcollation = index->indexcollations[indexcol];
2583 :
2584 : /*
2585 : * Check for clauses of the form: (indexkey operator constant) or
2586 : * (constant operator indexkey). See match_clause_to_indexcol's notes
2587 : * about const-ness.
2588 : *
2589 : * Note that we don't ask the support function about clauses that don't
2590 : * have one of these forms. Again, in principle it might be possible to
2591 : * do something, but it seems unlikely to be worth the cycles to check.
2592 : */
2593 801690 : if (match_index_to_operand(leftop, indexcol, index) &&
2594 365104 : !bms_is_member(index_relid, rinfo->right_relids) &&
2595 182520 : !contain_volatile_functions(rightop))
2596 : {
2597 362994 : if (IndexCollMatchesExprColl(idxcollation, expr_coll) &&
2598 180474 : op_in_opfamily(expr_op, opfamily))
2599 : {
2600 176724 : iclause = makeNode(IndexClause);
2601 176724 : iclause->rinfo = rinfo;
2602 176724 : iclause->indexquals = list_make1(rinfo);
2603 176724 : iclause->lossy = false;
2604 176724 : iclause->indexcol = indexcol;
2605 176724 : iclause->indexcols = NIL;
2606 176724 : return iclause;
2607 : }
2608 :
2609 : /*
2610 : * If we didn't find a member of the index's opfamily, try the support
2611 : * function for the operator's underlying function.
2612 : */
2613 5796 : set_opfuncid(clause); /* make sure we have opfuncid */
2614 5796 : return get_index_clause_from_support(root,
2615 : rinfo,
2616 : clause->opfuncid,
2617 : 0, /* indexarg on left */
2618 : indexcol,
2619 : index);
2620 : }
2621 :
2622 455206 : if (match_index_to_operand(rightop, indexcol, index) &&
2623 37204 : !bms_is_member(index_relid, rinfo->left_relids) &&
2624 18584 : !contain_volatile_functions(leftop))
2625 : {
2626 18584 : if (IndexCollMatchesExprColl(idxcollation, expr_coll))
2627 : {
2628 18584 : Oid comm_op = get_commutator(expr_op);
2629 :
2630 37168 : if (OidIsValid(comm_op) &&
2631 18584 : op_in_opfamily(comm_op, opfamily))
2632 : {
2633 : RestrictInfo *commrinfo;
2634 :
2635 : /* Build a commuted OpExpr and RestrictInfo */
2636 18350 : commrinfo = commute_restrictinfo(rinfo, comm_op);
2637 :
2638 : /* Make an IndexClause showing that as a derived qual */
2639 18350 : iclause = makeNode(IndexClause);
2640 18350 : iclause->rinfo = rinfo;
2641 18350 : iclause->indexquals = list_make1(commrinfo);
2642 18350 : iclause->lossy = false;
2643 18350 : iclause->indexcol = indexcol;
2644 18350 : iclause->indexcols = NIL;
2645 18350 : return iclause;
2646 : }
2647 : }
2648 :
2649 : /*
2650 : * If we didn't find a member of the index's opfamily, try the support
2651 : * function for the operator's underlying function.
2652 : */
2653 234 : set_opfuncid(clause); /* make sure we have opfuncid */
2654 234 : return get_index_clause_from_support(root,
2655 : rinfo,
2656 : clause->opfuncid,
2657 : 1, /* indexarg on right */
2658 : indexcol,
2659 : index);
2660 : }
2661 :
2662 418002 : return NULL;
2663 : }
2664 :
2665 : /*
2666 : * match_funcclause_to_indexcol()
2667 : * Handles the FuncExpr case for match_clause_to_indexcol(),
2668 : * which see for comments.
2669 : */
2670 : static IndexClause *
2671 11072 : match_funcclause_to_indexcol(PlannerInfo *root,
2672 : RestrictInfo *rinfo,
2673 : int indexcol,
2674 : IndexOptInfo *index)
2675 : {
2676 11072 : FuncExpr *clause = (FuncExpr *) rinfo->clause;
2677 : int indexarg;
2678 : ListCell *lc;
2679 :
2680 : /*
2681 : * We have no built-in intelligence about function clauses, but if there's
2682 : * a planner support function, it might be able to do something. But, to
2683 : * cut down on wasted planning cycles, only call the support function if
2684 : * at least one argument matches the target index column.
2685 : *
2686 : * Note that we don't insist on the other arguments being pseudoconstants;
2687 : * the support function has to check that. This is to allow cases where
2688 : * only some of the other arguments need to be included in the indexqual.
2689 : */
2690 11072 : indexarg = 0;
2691 23866 : foreach(lc, clause->args)
2692 : {
2693 14608 : Node *op = (Node *) lfirst(lc);
2694 :
2695 14608 : if (match_index_to_operand(op, indexcol, index))
2696 : {
2697 1814 : return get_index_clause_from_support(root,
2698 : rinfo,
2699 : clause->funcid,
2700 : indexarg,
2701 : indexcol,
2702 : index);
2703 : }
2704 :
2705 12794 : indexarg++;
2706 : }
2707 :
2708 9258 : return NULL;
2709 : }
2710 :
2711 : /*
2712 : * get_index_clause_from_support()
2713 : * If the function has a planner support function, try to construct
2714 : * an IndexClause using indexquals created by the support function.
2715 : */
2716 : static IndexClause *
2717 7844 : get_index_clause_from_support(PlannerInfo *root,
2718 : RestrictInfo *rinfo,
2719 : Oid funcid,
2720 : int indexarg,
2721 : int indexcol,
2722 : IndexOptInfo *index)
2723 : {
2724 7844 : Oid prosupport = get_func_support(funcid);
2725 : SupportRequestIndexCondition req;
2726 : List *sresult;
2727 :
2728 7844 : if (!OidIsValid(prosupport))
2729 4750 : return NULL;
2730 :
2731 3094 : req.type = T_SupportRequestIndexCondition;
2732 3094 : req.root = root;
2733 3094 : req.funcid = funcid;
2734 3094 : req.node = (Node *) rinfo->clause;
2735 3094 : req.indexarg = indexarg;
2736 3094 : req.index = index;
2737 3094 : req.indexcol = indexcol;
2738 3094 : req.opfamily = index->opfamily[indexcol];
2739 3094 : req.indexcollation = index->indexcollations[indexcol];
2740 :
2741 3094 : req.lossy = true; /* default assumption */
2742 :
2743 3094 : sresult = (List *)
2744 3094 : DatumGetPointer(OidFunctionCall1(prosupport,
2745 : PointerGetDatum(&req)));
2746 :
2747 3094 : if (sresult != NIL)
2748 : {
2749 2956 : IndexClause *iclause = makeNode(IndexClause);
2750 2956 : List *indexquals = NIL;
2751 : ListCell *lc;
2752 :
2753 : /*
2754 : * The support function API says it should just give back bare
2755 : * clauses, so here we must wrap each one in a RestrictInfo.
2756 : */
2757 6856 : foreach(lc, sresult)
2758 : {
2759 3900 : Expr *clause = (Expr *) lfirst(lc);
2760 :
2761 3900 : indexquals = lappend(indexquals, make_simple_restrictinfo(clause));
2762 : }
2763 :
2764 2956 : iclause->rinfo = rinfo;
2765 2956 : iclause->indexquals = indexquals;
2766 2956 : iclause->lossy = req.lossy;
2767 2956 : iclause->indexcol = indexcol;
2768 2956 : iclause->indexcols = NIL;
2769 :
2770 2956 : return iclause;
2771 : }
2772 :
2773 138 : return NULL;
2774 : }
2775 :
2776 : /*
2777 : * match_saopclause_to_indexcol()
2778 : * Handles the ScalarArrayOpExpr case for match_clause_to_indexcol(),
2779 : * which see for comments.
2780 : */
2781 : static IndexClause *
2782 47746 : match_saopclause_to_indexcol(RestrictInfo *rinfo,
2783 : int indexcol,
2784 : IndexOptInfo *index)
2785 : {
2786 47746 : ScalarArrayOpExpr *saop = (ScalarArrayOpExpr *) rinfo->clause;
2787 : Node *leftop,
2788 : *rightop;
2789 : Relids right_relids;
2790 : Oid expr_op;
2791 : Oid expr_coll;
2792 : Index index_relid;
2793 : Oid opfamily;
2794 : Oid idxcollation;
2795 :
2796 : /* We only accept ANY clauses, not ALL */
2797 47746 : if (!saop->useOr)
2798 1290 : return NULL;
2799 46456 : leftop = (Node *) linitial(saop->args);
2800 46456 : rightop = (Node *) lsecond(saop->args);
2801 46456 : right_relids = pull_varnos(rightop);
2802 46456 : expr_op = saop->opno;
2803 46456 : expr_coll = saop->inputcollid;
2804 :
2805 46456 : index_relid = index->rel->relid;
2806 46456 : opfamily = index->opfamily[indexcol];
2807 46456 : idxcollation = index->indexcollations[indexcol];
2808 :
2809 : /*
2810 : * We must have indexkey on the left and a pseudo-constant array argument.
2811 : */
2812 53154 : if (match_index_to_operand(leftop, indexcol, index) &&
2813 13396 : !bms_is_member(index_relid, right_relids) &&
2814 6698 : !contain_volatile_functions(rightop))
2815 : {
2816 13392 : if (IndexCollMatchesExprColl(idxcollation, expr_coll) &&
2817 6694 : op_in_opfamily(expr_op, opfamily))
2818 : {
2819 6686 : IndexClause *iclause = makeNode(IndexClause);
2820 :
2821 6686 : iclause->rinfo = rinfo;
2822 6686 : iclause->indexquals = list_make1(rinfo);
2823 6686 : iclause->lossy = false;
2824 6686 : iclause->indexcol = indexcol;
2825 6686 : iclause->indexcols = NIL;
2826 6686 : return iclause;
2827 : }
2828 :
2829 : /*
2830 : * We do not currently ask support functions about ScalarArrayOpExprs,
2831 : * though in principle we could.
2832 : */
2833 : }
2834 :
2835 39770 : return NULL;
2836 : }
2837 :
2838 : /*
2839 : * match_rowcompare_to_indexcol()
2840 : * Handles the RowCompareExpr case for match_clause_to_indexcol(),
2841 : * which see for comments.
2842 : *
2843 : * In this routine we check whether the first column of the row comparison
2844 : * matches the target index column. This is sufficient to guarantee that some
2845 : * index condition can be constructed from the RowCompareExpr --- the rest
2846 : * is handled by expand_indexqual_rowcompare().
2847 : */
2848 : static IndexClause *
2849 192 : match_rowcompare_to_indexcol(RestrictInfo *rinfo,
2850 : int indexcol,
2851 : IndexOptInfo *index)
2852 : {
2853 192 : RowCompareExpr *clause = (RowCompareExpr *) rinfo->clause;
2854 : Index index_relid;
2855 : Oid opfamily;
2856 : Oid idxcollation;
2857 : Node *leftop,
2858 : *rightop;
2859 : bool var_on_left;
2860 : Oid expr_op;
2861 : Oid expr_coll;
2862 :
2863 : /* Forget it if we're not dealing with a btree index */
2864 192 : if (index->relam != BTREE_AM_OID)
2865 0 : return NULL;
2866 :
2867 192 : index_relid = index->rel->relid;
2868 192 : opfamily = index->opfamily[indexcol];
2869 192 : idxcollation = index->indexcollations[indexcol];
2870 :
2871 : /*
2872 : * We could do the matching on the basis of insisting that the opfamily
2873 : * shown in the RowCompareExpr be the same as the index column's opfamily,
2874 : * but that could fail in the presence of reverse-sort opfamilies: it'd be
2875 : * a matter of chance whether RowCompareExpr had picked the forward or
2876 : * reverse-sort family. So look only at the operator, and match if it is
2877 : * a member of the index's opfamily (after commutation, if the indexkey is
2878 : * on the right). We'll worry later about whether any additional
2879 : * operators are matchable to the index.
2880 : */
2881 192 : leftop = (Node *) linitial(clause->largs);
2882 192 : rightop = (Node *) linitial(clause->rargs);
2883 192 : expr_op = linitial_oid(clause->opnos);
2884 192 : expr_coll = linitial_oid(clause->inputcollids);
2885 :
2886 : /* Collations must match, if relevant */
2887 192 : if (!IndexCollMatchesExprColl(idxcollation, expr_coll))
2888 0 : return NULL;
2889 :
2890 : /*
2891 : * These syntactic tests are the same as in match_opclause_to_indexcol()
2892 : */
2893 236 : if (match_index_to_operand(leftop, indexcol, index) &&
2894 88 : !bms_is_member(index_relid, pull_varnos(rightop)) &&
2895 44 : !contain_volatile_functions(rightop))
2896 : {
2897 : /* OK, indexkey is on left */
2898 44 : var_on_left = true;
2899 : }
2900 164 : else if (match_index_to_operand(rightop, indexcol, index) &&
2901 32 : !bms_is_member(index_relid, pull_varnos(leftop)) &&
2902 16 : !contain_volatile_functions(leftop))
2903 : {
2904 : /* indexkey is on right, so commute the operator */
2905 16 : expr_op = get_commutator(expr_op);
2906 16 : if (expr_op == InvalidOid)
2907 0 : return NULL;
2908 16 : var_on_left = false;
2909 : }
2910 : else
2911 132 : return NULL;
2912 :
2913 : /* We're good if the operator is the right type of opfamily member */
2914 60 : switch (get_op_opfamily_strategy(expr_op, opfamily))
2915 : {
2916 : case BTLessStrategyNumber:
2917 : case BTLessEqualStrategyNumber:
2918 : case BTGreaterEqualStrategyNumber:
2919 : case BTGreaterStrategyNumber:
2920 60 : return expand_indexqual_rowcompare(rinfo,
2921 : indexcol,
2922 : index,
2923 : expr_op,
2924 : var_on_left);
2925 : }
2926 :
2927 0 : return NULL;
2928 : }
2929 :
2930 : /*
2931 : * expand_indexqual_rowcompare --- expand a single indexqual condition
2932 : * that is a RowCompareExpr
2933 : *
2934 : * It's already known that the first column of the row comparison matches
2935 : * the specified column of the index. We can use additional columns of the
2936 : * row comparison as index qualifications, so long as they match the index
2937 : * in the "same direction", ie, the indexkeys are all on the same side of the
2938 : * clause and the operators are all the same-type members of the opfamilies.
2939 : *
2940 : * If all the columns of the RowCompareExpr match in this way, we just use it
2941 : * as-is, except for possibly commuting it to put the indexkeys on the left.
2942 : *
2943 : * Otherwise, we build a shortened RowCompareExpr (if more than one
2944 : * column matches) or a simple OpExpr (if the first-column match is all
2945 : * there is). In these cases the modified clause is always "<=" or ">="
2946 : * even when the original was "<" or ">" --- this is necessary to match all
2947 : * the rows that could match the original. (We are building a lossy version
2948 : * of the row comparison when we do this, so we set lossy = true.)
2949 : *
2950 : * Note: this is really just the last half of match_rowcompare_to_indexcol,
2951 : * but we split it out for comprehensibility.
2952 : */
2953 : static IndexClause *
2954 60 : expand_indexqual_rowcompare(RestrictInfo *rinfo,
2955 : int indexcol,
2956 : IndexOptInfo *index,
2957 : Oid expr_op,
2958 : bool var_on_left)
2959 : {
2960 60 : IndexClause *iclause = makeNode(IndexClause);
2961 60 : RowCompareExpr *clause = (RowCompareExpr *) rinfo->clause;
2962 : int op_strategy;
2963 : Oid op_lefttype;
2964 : Oid op_righttype;
2965 : int matching_cols;
2966 : List *expr_ops;
2967 : List *opfamilies;
2968 : List *lefttypes;
2969 : List *righttypes;
2970 : List *new_ops;
2971 : List *var_args;
2972 : List *non_var_args;
2973 : ListCell *vargs_cell;
2974 : ListCell *nargs_cell;
2975 : ListCell *opnos_cell;
2976 : ListCell *collids_cell;
2977 :
2978 60 : iclause->rinfo = rinfo;
2979 60 : iclause->indexcol = indexcol;
2980 :
2981 60 : if (var_on_left)
2982 : {
2983 44 : var_args = clause->largs;
2984 44 : non_var_args = clause->rargs;
2985 : }
2986 : else
2987 : {
2988 16 : var_args = clause->rargs;
2989 16 : non_var_args = clause->largs;
2990 : }
2991 :
2992 60 : get_op_opfamily_properties(expr_op, index->opfamily[indexcol], false,
2993 : &op_strategy,
2994 : &op_lefttype,
2995 : &op_righttype);
2996 :
2997 : /* Initialize returned list of which index columns are used */
2998 60 : iclause->indexcols = list_make1_int(indexcol);
2999 :
3000 : /* Build lists of ops, opfamilies and operator datatypes in case needed */
3001 60 : expr_ops = list_make1_oid(expr_op);
3002 60 : opfamilies = list_make1_oid(index->opfamily[indexcol]);
3003 60 : lefttypes = list_make1_oid(op_lefttype);
3004 60 : righttypes = list_make1_oid(op_righttype);
3005 :
3006 : /*
3007 : * See how many of the remaining columns match some index column in the
3008 : * same way. As in match_clause_to_indexcol(), the "other" side of any
3009 : * potential index condition is OK as long as it doesn't use Vars from the
3010 : * indexed relation.
3011 : */
3012 60 : matching_cols = 1;
3013 60 : vargs_cell = lnext(list_head(var_args));
3014 60 : nargs_cell = lnext(list_head(non_var_args));
3015 60 : opnos_cell = lnext(list_head(clause->opnos));
3016 60 : collids_cell = lnext(list_head(clause->inputcollids));
3017 :
3018 168 : while (vargs_cell != NULL)
3019 : {
3020 84 : Node *varop = (Node *) lfirst(vargs_cell);
3021 84 : Node *constop = (Node *) lfirst(nargs_cell);
3022 : int i;
3023 :
3024 84 : expr_op = lfirst_oid(opnos_cell);
3025 84 : if (!var_on_left)
3026 : {
3027 : /* indexkey is on right, so commute the operator */
3028 16 : expr_op = get_commutator(expr_op);
3029 16 : if (expr_op == InvalidOid)
3030 0 : break; /* operator is not usable */
3031 : }
3032 84 : if (bms_is_member(index->rel->relid, pull_varnos(constop)))
3033 0 : break; /* no good, Var on wrong side */
3034 84 : if (contain_volatile_functions(constop))
3035 0 : break; /* no good, volatile comparison value */
3036 :
3037 : /*
3038 : * The Var side can match any key column of the index.
3039 : */
3040 200 : for (i = 0; i < index->nkeycolumns; i++)
3041 : {
3042 212 : if (match_index_to_operand(varop, i, index) &&
3043 48 : get_op_opfamily_strategy(expr_op,
3044 144 : index->opfamily[i]) == op_strategy &&
3045 56 : IndexCollMatchesExprColl(index->indexcollations[i],
3046 : lfirst_oid(collids_cell)))
3047 : break;
3048 : }
3049 84 : if (i >= index->nkeycolumns)
3050 36 : break; /* no match found */
3051 :
3052 : /* Add column number to returned list */
3053 48 : iclause->indexcols = lappend_int(iclause->indexcols, i);
3054 :
3055 : /* Add operator info to lists */
3056 48 : get_op_opfamily_properties(expr_op, index->opfamily[i], false,
3057 : &op_strategy,
3058 : &op_lefttype,
3059 : &op_righttype);
3060 48 : expr_ops = lappend_oid(expr_ops, expr_op);
3061 48 : opfamilies = lappend_oid(opfamilies, index->opfamily[i]);
3062 48 : lefttypes = lappend_oid(lefttypes, op_lefttype);
3063 48 : righttypes = lappend_oid(righttypes, op_righttype);
3064 :
3065 : /* This column matches, keep scanning */
3066 48 : matching_cols++;
3067 48 : vargs_cell = lnext(vargs_cell);
3068 48 : nargs_cell = lnext(nargs_cell);
3069 48 : opnos_cell = lnext(opnos_cell);
3070 48 : collids_cell = lnext(collids_cell);
3071 : }
3072 :
3073 : /* Result is non-lossy if all columns are usable as index quals */
3074 60 : iclause->lossy = (matching_cols != list_length(clause->opnos));
3075 :
3076 : /*
3077 : * We can use rinfo->clause as-is if we have var on left and it's all
3078 : * usable as index quals.
3079 : */
3080 60 : if (var_on_left && !iclause->lossy)
3081 16 : iclause->indexquals = list_make1(rinfo);
3082 : else
3083 : {
3084 : /*
3085 : * We have to generate a modified rowcompare (possibly just one
3086 : * OpExpr). The painful part of this is changing < to <= or > to >=,
3087 : * so deal with that first.
3088 : */
3089 44 : if (!iclause->lossy)
3090 : {
3091 : /* very easy, just use the commuted operators */
3092 8 : new_ops = expr_ops;
3093 : }
3094 72 : else if (op_strategy == BTLessEqualStrategyNumber ||
3095 36 : op_strategy == BTGreaterEqualStrategyNumber)
3096 : {
3097 : /* easy, just use the same (possibly commuted) operators */
3098 0 : new_ops = list_truncate(expr_ops, matching_cols);
3099 : }
3100 : else
3101 : {
3102 : ListCell *opfamilies_cell;
3103 : ListCell *lefttypes_cell;
3104 : ListCell *righttypes_cell;
3105 :
3106 36 : if (op_strategy == BTLessStrategyNumber)
3107 20 : op_strategy = BTLessEqualStrategyNumber;
3108 16 : else if (op_strategy == BTGreaterStrategyNumber)
3109 16 : op_strategy = BTGreaterEqualStrategyNumber;
3110 : else
3111 0 : elog(ERROR, "unexpected strategy number %d", op_strategy);
3112 36 : new_ops = NIL;
3113 96 : forthree(opfamilies_cell, opfamilies,
3114 : lefttypes_cell, lefttypes,
3115 : righttypes_cell, righttypes)
3116 : {
3117 60 : Oid opfam = lfirst_oid(opfamilies_cell);
3118 60 : Oid lefttype = lfirst_oid(lefttypes_cell);
3119 60 : Oid righttype = lfirst_oid(righttypes_cell);
3120 :
3121 60 : expr_op = get_opfamily_member(opfam, lefttype, righttype,
3122 : op_strategy);
3123 60 : if (!OidIsValid(expr_op)) /* should not happen */
3124 0 : elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
3125 : op_strategy, lefttype, righttype, opfam);
3126 60 : new_ops = lappend_oid(new_ops, expr_op);
3127 : }
3128 : }
3129 :
3130 : /* If we have more than one matching col, create a subset rowcompare */
3131 44 : if (matching_cols > 1)
3132 : {
3133 32 : RowCompareExpr *rc = makeNode(RowCompareExpr);
3134 :
3135 32 : rc->rctype = (RowCompareType) op_strategy;
3136 32 : rc->opnos = new_ops;
3137 32 : rc->opfamilies = list_truncate(list_copy(clause->opfamilies),
3138 : matching_cols);
3139 32 : rc->inputcollids = list_truncate(list_copy(clause->inputcollids),
3140 : matching_cols);
3141 32 : rc->largs = list_truncate(copyObject(var_args),
3142 : matching_cols);
3143 32 : rc->rargs = list_truncate(copyObject(non_var_args),
3144 : matching_cols);
3145 32 : iclause->indexquals = list_make1(make_simple_restrictinfo((Expr *) rc));
3146 : }
3147 : else
3148 : {
3149 : Expr *op;
3150 :
3151 : /* We don't report an index column list in this case */
3152 12 : iclause->indexcols = NIL;
3153 :
3154 24 : op = make_opclause(linitial_oid(new_ops), BOOLOID, false,
3155 12 : copyObject(linitial(var_args)),
3156 12 : copyObject(linitial(non_var_args)),
3157 : InvalidOid,
3158 12 : linitial_oid(clause->inputcollids));
3159 12 : iclause->indexquals = list_make1(make_simple_restrictinfo(op));
3160 : }
3161 : }
3162 :
3163 60 : return iclause;
3164 : }
3165 :
3166 :
3167 : /****************************************************************************
3168 : * ---- ROUTINES TO CHECK ORDERING OPERATORS ----
3169 : ****************************************************************************/
3170 :
3171 : /*
3172 : * match_pathkeys_to_index
3173 : * Test whether an index can produce output ordered according to the
3174 : * given pathkeys using "ordering operators".
3175 : *
3176 : * If it can, return a list of suitable ORDER BY expressions, each of the form
3177 : * "indexedcol operator pseudoconstant", along with an integer list of the
3178 : * index column numbers (zero based) that each clause would be used with.
3179 : * NIL lists are returned if the ordering is not achievable this way.
3180 : *
3181 : * On success, the result list is ordered by pathkeys, and in fact is
3182 : * one-to-one with the requested pathkeys.
3183 : */
3184 : static void
3185 494 : match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys,
3186 : List **orderby_clauses_p,
3187 : List **clause_columns_p)
3188 : {
3189 494 : List *orderby_clauses = NIL;
3190 494 : List *clause_columns = NIL;
3191 : ListCell *lc1;
3192 :
3193 494 : *orderby_clauses_p = NIL; /* set default results */
3194 494 : *clause_columns_p = NIL;
3195 :
3196 : /* Only indexes with the amcanorderbyop property are interesting here */
3197 494 : if (!index->amcanorderbyop)
3198 0 : return;
3199 :
3200 762 : foreach(lc1, pathkeys)
3201 : {
3202 486 : PathKey *pathkey = (PathKey *) lfirst(lc1);
3203 486 : bool found = false;
3204 : ListCell *lc2;
3205 :
3206 : /*
3207 : * Note: for any failure to match, we just return NIL immediately.
3208 : * There is no value in matching just some of the pathkeys.
3209 : */
3210 :
3211 : /* Pathkey must request default sort order for the target opfamily */
3212 950 : if (pathkey->pk_strategy != BTLessStrategyNumber ||
3213 464 : pathkey->pk_nulls_first)
3214 22 : return;
3215 :
3216 : /* If eclass is volatile, no hope of using an indexscan */
3217 464 : if (pathkey->pk_eclass->ec_has_volatile)
3218 0 : return;
3219 :
3220 : /*
3221 : * Try to match eclass member expression(s) to index. Note that child
3222 : * EC members are considered, but only when they belong to the target
3223 : * relation. (Unlike regular members, the same expression could be a
3224 : * child member of more than one EC. Therefore, the same index could
3225 : * be considered to match more than one pathkey list, which is OK
3226 : * here. See also get_eclass_for_sort_expr.)
3227 : */
3228 660 : foreach(lc2, pathkey->pk_eclass->ec_members)
3229 : {
3230 464 : EquivalenceMember *member = (EquivalenceMember *) lfirst(lc2);
3231 : int indexcol;
3232 :
3233 : /* No possibility of match if it references other relations */
3234 464 : if (!bms_equal(member->em_relids, index->rel->relids))
3235 0 : continue;
3236 :
3237 : /*
3238 : * We allow any column of the index to match each pathkey; they
3239 : * don't have to match left-to-right as you might expect. This is
3240 : * correct for GiST, and it doesn't matter for SP-GiST because
3241 : * that doesn't handle multiple columns anyway, and no other
3242 : * existing AMs support amcanorderbyop. We might need different
3243 : * logic in future for other implementations.
3244 : */
3245 660 : for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
3246 : {
3247 : Expr *expr;
3248 :
3249 464 : expr = match_clause_to_ordering_op(index,
3250 : indexcol,
3251 : member->em_expr,
3252 : pathkey->pk_opfamily);
3253 464 : if (expr)
3254 : {
3255 268 : orderby_clauses = lappend(orderby_clauses, expr);
3256 268 : clause_columns = lappend_int(clause_columns, indexcol);
3257 268 : found = true;
3258 268 : break;
3259 : }
3260 : }
3261 :
3262 464 : if (found) /* don't want to look at remaining members */
3263 268 : break;
3264 : }
3265 :
3266 464 : if (!found) /* fail if no match for this pathkey */
3267 196 : return;
3268 : }
3269 :
3270 276 : *orderby_clauses_p = orderby_clauses; /* success! */
3271 276 : *clause_columns_p = clause_columns;
3272 : }
3273 :
3274 : /*
3275 : * match_clause_to_ordering_op
3276 : * Determines whether an ordering operator expression matches an
3277 : * index column.
3278 : *
3279 : * This is similar to, but simpler than, match_clause_to_indexcol.
3280 : * We only care about simple OpExpr cases. The input is a bare
3281 : * expression that is being ordered by, which must be of the form
3282 : * (indexkey op const) or (const op indexkey) where op is an ordering
3283 : * operator for the column's opfamily.
3284 : *
3285 : * 'index' is the index of interest.
3286 : * 'indexcol' is a column number of 'index' (counting from 0).
3287 : * 'clause' is the ordering expression to be tested.
3288 : * 'pk_opfamily' is the btree opfamily describing the required sort order.
3289 : *
3290 : * Note that we currently do not consider the collation of the ordering
3291 : * operator's result. In practical cases the result type will be numeric
3292 : * and thus have no collation, and it's not very clear what to match to
3293 : * if it did have a collation. The index's collation should match the
3294 : * ordering operator's input collation, not its result.
3295 : *
3296 : * If successful, return 'clause' as-is if the indexkey is on the left,
3297 : * otherwise a commuted copy of 'clause'. If no match, return NULL.
3298 : */
3299 : static Expr *
3300 464 : match_clause_to_ordering_op(IndexOptInfo *index,
3301 : int indexcol,
3302 : Expr *clause,
3303 : Oid pk_opfamily)
3304 : {
3305 : Oid opfamily;
3306 : Oid idxcollation;
3307 : Node *leftop,
3308 : *rightop;
3309 : Oid expr_op;
3310 : Oid expr_coll;
3311 : Oid sortfamily;
3312 : bool commuted;
3313 :
3314 : Assert(indexcol < index->nkeycolumns);
3315 :
3316 464 : opfamily = index->opfamily[indexcol];
3317 464 : idxcollation = index->indexcollations[indexcol];
3318 :
3319 : /*
3320 : * Clause must be a binary opclause.
3321 : */
3322 464 : if (!is_opclause(clause))
3323 196 : return NULL;
3324 268 : leftop = get_leftop(clause);
3325 268 : rightop = get_rightop(clause);
3326 268 : if (!leftop || !rightop)
3327 0 : return NULL;
3328 268 : expr_op = ((OpExpr *) clause)->opno;
3329 268 : expr_coll = ((OpExpr *) clause)->inputcollid;
3330 :
3331 : /*
3332 : * We can forget the whole thing right away if wrong collation.
3333 : */
3334 268 : if (!IndexCollMatchesExprColl(idxcollation, expr_coll))
3335 0 : return NULL;
3336 :
3337 : /*
3338 : * Check for clauses of the form: (indexkey operator constant) or
3339 : * (constant operator indexkey).
3340 : */
3341 528 : if (match_index_to_operand(leftop, indexcol, index) &&
3342 520 : !contain_var_clause(rightop) &&
3343 260 : !contain_volatile_functions(rightop))
3344 : {
3345 260 : commuted = false;
3346 : }
3347 16 : else if (match_index_to_operand(rightop, indexcol, index) &&
3348 16 : !contain_var_clause(leftop) &&
3349 8 : !contain_volatile_functions(leftop))
3350 : {
3351 : /* Might match, but we need a commuted operator */
3352 8 : expr_op = get_commutator(expr_op);
3353 8 : if (expr_op == InvalidOid)
3354 0 : return NULL;
3355 8 : commuted = true;
3356 : }
3357 : else
3358 0 : return NULL;
3359 :
3360 : /*
3361 : * Is the (commuted) operator an ordering operator for the opfamily? And
3362 : * if so, does it yield the right sorting semantics?
3363 : */
3364 268 : sortfamily = get_op_opfamily_sortfamily(expr_op, opfamily);
3365 268 : if (sortfamily != pk_opfamily)
3366 0 : return NULL;
3367 :
3368 : /* We have a match. Return clause or a commuted version thereof. */
3369 268 : if (commuted)
3370 : {
3371 8 : OpExpr *newclause = makeNode(OpExpr);
3372 :
3373 : /* flat-copy all the fields of clause */
3374 8 : memcpy(newclause, clause, sizeof(OpExpr));
3375 :
3376 : /* commute it */
3377 8 : newclause->opno = expr_op;
3378 8 : newclause->opfuncid = InvalidOid;
3379 8 : newclause->args = list_make2(rightop, leftop);
3380 :
3381 8 : clause = (Expr *) newclause;
3382 : }
3383 :
3384 268 : return clause;
3385 : }
3386 :
3387 :
3388 : /****************************************************************************
3389 : * ---- ROUTINES TO DO PARTIAL INDEX PREDICATE TESTS ----
3390 : ****************************************************************************/
3391 :
3392 : /*
3393 : * check_index_predicates
3394 : * Set the predicate-derived IndexOptInfo fields for each index
3395 : * of the specified relation.
3396 : *
3397 : * predOK is set true if the index is partial and its predicate is satisfied
3398 : * for this query, ie the query's WHERE clauses imply the predicate.
3399 : *
3400 : * indrestrictinfo is set to the relation's baserestrictinfo list less any
3401 : * conditions that are implied by the index's predicate. (Obviously, for a
3402 : * non-partial index, this is the same as baserestrictinfo.) Such conditions
3403 : * can be dropped from the plan when using the index, in certain cases.
3404 : *
3405 : * At one time it was possible for this to get re-run after adding more
3406 : * restrictions to the rel, thus possibly letting us prove more indexes OK.
3407 : * That doesn't happen any more (at least not in the core code's usage),
3408 : * but this code still supports it in case extensions want to mess with the
3409 : * baserestrictinfo list. We assume that adding more restrictions can't make
3410 : * an index not predOK. We must recompute indrestrictinfo each time, though,
3411 : * to make sure any newly-added restrictions get into it if needed.
3412 : */
3413 : void
3414 216756 : check_index_predicates(PlannerInfo *root, RelOptInfo *rel)
3415 : {
3416 : List *clauselist;
3417 : bool have_partial;
3418 : bool is_target_rel;
3419 : Relids otherrels;
3420 : ListCell *lc;
3421 :
3422 : /* Indexes are available only on base or "other" member relations. */
3423 : Assert(IS_SIMPLE_REL(rel));
3424 :
3425 : /*
3426 : * Initialize the indrestrictinfo lists to be identical to
3427 : * baserestrictinfo, and check whether there are any partial indexes. If
3428 : * not, this is all we need to do.
3429 : */
3430 216756 : have_partial = false;
3431 591582 : foreach(lc, rel->indexlist)
3432 : {
3433 374826 : IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
3434 :
3435 374826 : index->indrestrictinfo = rel->baserestrictinfo;
3436 374826 : if (index->indpred)
3437 648 : have_partial = true;
3438 : }
3439 216756 : if (!have_partial)
3440 216336 : return;
3441 :
3442 : /*
3443 : * Construct a list of clauses that we can assume true for the purpose of
3444 : * proving the index(es) usable. Restriction clauses for the rel are
3445 : * always usable, and so are any join clauses that are "movable to" this
3446 : * rel. Also, we can consider any EC-derivable join clauses (which must
3447 : * be "movable to" this rel, by definition).
3448 : */
3449 420 : clauselist = list_copy(rel->baserestrictinfo);
3450 :
3451 : /* Scan the rel's join clauses */
3452 420 : foreach(lc, rel->joininfo)
3453 : {
3454 0 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
3455 :
3456 : /* Check if clause can be moved to this rel */
3457 0 : if (!join_clause_is_movable_to(rinfo, rel))
3458 0 : continue;
3459 :
3460 0 : clauselist = lappend(clauselist, rinfo);
3461 : }
3462 :
3463 : /*
3464 : * Add on any equivalence-derivable join clauses. Computing the correct
3465 : * relid sets for generate_join_implied_equalities is slightly tricky
3466 : * because the rel could be a child rel rather than a true baserel, and in
3467 : * that case we must remove its parents' relid(s) from all_baserels.
3468 : */
3469 420 : if (rel->reloptkind == RELOPT_OTHER_MEMBER_REL)
3470 48 : otherrels = bms_difference(root->all_baserels,
3471 48 : find_childrel_parents(root, rel));
3472 : else
3473 372 : otherrels = bms_difference(root->all_baserels, rel->relids);
3474 :
3475 420 : if (!bms_is_empty(otherrels))
3476 26 : clauselist =
3477 26 : list_concat(clauselist,
3478 : generate_join_implied_equalities(root,
3479 26 : bms_union(rel->relids,
3480 : otherrels),
3481 : otherrels,
3482 : rel));
3483 :
3484 : /*
3485 : * Normally we remove quals that are implied by a partial index's
3486 : * predicate from indrestrictinfo, indicating that they need not be
3487 : * checked explicitly by an indexscan plan using this index. However, if
3488 : * the rel is a target relation of UPDATE/DELETE/SELECT FOR UPDATE, we
3489 : * cannot remove such quals from the plan, because they need to be in the
3490 : * plan so that they will be properly rechecked by EvalPlanQual testing.
3491 : * Some day we might want to remove such quals from the main plan anyway
3492 : * and pass them through to EvalPlanQual via a side channel; but for now,
3493 : * we just don't remove implied quals at all for target relations.
3494 : */
3495 732 : is_target_rel = (rel->relid == root->parse->resultRelation ||
3496 312 : get_plan_rowmark(root->rowMarks, rel->relid) != NULL);
3497 :
3498 : /*
3499 : * Now try to prove each index predicate true, and compute the
3500 : * indrestrictinfo lists for partial indexes. Note that we compute the
3501 : * indrestrictinfo list even for non-predOK indexes; this might seem
3502 : * wasteful, but we may be able to use such indexes in OR clauses, cf
3503 : * generate_bitmap_or_paths().
3504 : */
3505 1236 : foreach(lc, rel->indexlist)
3506 : {
3507 816 : IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
3508 : ListCell *lcr;
3509 :
3510 816 : if (index->indpred == NIL)
3511 168 : continue; /* ignore non-partial indexes here */
3512 :
3513 648 : if (!index->predOK) /* don't repeat work if already proven OK */
3514 648 : index->predOK = predicate_implied_by(index->indpred, clauselist,
3515 : false);
3516 :
3517 : /* If rel is an update target, leave indrestrictinfo as set above */
3518 648 : if (is_target_rel)
3519 156 : continue;
3520 :
3521 : /* Else compute indrestrictinfo as the non-implied quals */
3522 492 : index->indrestrictinfo = NIL;
3523 1138 : foreach(lcr, rel->baserestrictinfo)
3524 : {
3525 646 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lcr);
3526 :
3527 : /* predicate_implied_by() assumes first arg is immutable */
3528 1292 : if (contain_mutable_functions((Node *) rinfo->clause) ||
3529 646 : !predicate_implied_by(list_make1(rinfo->clause),
3530 : index->indpred, false))
3531 470 : index->indrestrictinfo = lappend(index->indrestrictinfo, rinfo);
3532 : }
3533 : }
3534 : }
3535 :
3536 : /****************************************************************************
3537 : * ---- ROUTINES TO CHECK EXTERNALLY-VISIBLE CONDITIONS ----
3538 : ****************************************************************************/
3539 :
3540 : /*
3541 : * ec_member_matches_indexcol
3542 : * Test whether an EquivalenceClass member matches an index column.
3543 : *
3544 : * This is a callback for use by generate_implied_equalities_for_column.
3545 : */
3546 : static bool
3547 122436 : ec_member_matches_indexcol(PlannerInfo *root, RelOptInfo *rel,
3548 : EquivalenceClass *ec, EquivalenceMember *em,
3549 : void *arg)
3550 : {
3551 122436 : IndexOptInfo *index = ((ec_member_matches_arg *) arg)->index;
3552 122436 : int indexcol = ((ec_member_matches_arg *) arg)->indexcol;
3553 : Oid curFamily;
3554 : Oid curCollation;
3555 :
3556 : Assert(indexcol < index->nkeycolumns);
3557 :
3558 122436 : curFamily = index->opfamily[indexcol];
3559 122436 : curCollation = index->indexcollations[indexcol];
3560 :
3561 : /*
3562 : * If it's a btree index, we can reject it if its opfamily isn't
3563 : * compatible with the EC, since no clause generated from the EC could be
3564 : * used with the index. For non-btree indexes, we can't easily tell
3565 : * whether clauses generated from the EC could be used with the index, so
3566 : * don't check the opfamily. This might mean we return "true" for a
3567 : * useless EC, so we have to recheck the results of
3568 : * generate_implied_equalities_for_column; see
3569 : * match_eclass_clauses_to_index.
3570 : */
3571 244868 : if (index->relam == BTREE_AM_OID &&
3572 122432 : !list_member_oid(ec->ec_opfamilies, curFamily))
3573 35120 : return false;
3574 :
3575 : /* We insist on collation match for all index types, though */
3576 87316 : if (!IndexCollMatchesExprColl(curCollation, ec->ec_collation))
3577 6 : return false;
3578 :
3579 87310 : return match_index_to_operand((Node *) em->em_expr, indexcol, index);
3580 : }
3581 :
3582 : /*
3583 : * relation_has_unique_index_for
3584 : * Determine whether the relation provably has at most one row satisfying
3585 : * a set of equality conditions, because the conditions constrain all
3586 : * columns of some unique index.
3587 : *
3588 : * The conditions can be represented in either or both of two ways:
3589 : * 1. A list of RestrictInfo nodes, where the caller has already determined
3590 : * that each condition is a mergejoinable equality with an expression in
3591 : * this relation on one side, and an expression not involving this relation
3592 : * on the other. The transient outer_is_left flag is used to identify which
3593 : * side we should look at: left side if outer_is_left is false, right side
3594 : * if it is true.
3595 : * 2. A list of expressions in this relation, and a corresponding list of
3596 : * equality operators. The caller must have already checked that the operators
3597 : * represent equality. (Note: the operators could be cross-type; the
3598 : * expressions should correspond to their RHS inputs.)
3599 : *
3600 : * The caller need only supply equality conditions arising from joins;
3601 : * this routine automatically adds in any usable baserestrictinfo clauses.
3602 : * (Note that the passed-in restrictlist will be destructively modified!)
3603 : */
3604 : bool
3605 111422 : relation_has_unique_index_for(PlannerInfo *root, RelOptInfo *rel,
3606 : List *restrictlist,
3607 : List *exprlist, List *oprlist)
3608 : {
3609 : ListCell *ic;
3610 :
3611 : Assert(list_length(exprlist) == list_length(oprlist));
3612 :
3613 : /* Short-circuit if no indexes... */
3614 111422 : if (rel->indexlist == NIL)
3615 164 : return false;
3616 :
3617 : /*
3618 : * Examine the rel's restriction clauses for usable var = const clauses
3619 : * that we can add to the restrictlist.
3620 : */
3621 211384 : foreach(ic, rel->baserestrictinfo)
3622 : {
3623 100126 : RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(ic);
3624 :
3625 : /*
3626 : * Note: can_join won't be set for a restriction clause, but
3627 : * mergeopfamilies will be if it has a mergejoinable operator and
3628 : * doesn't contain volatile functions.
3629 : */
3630 100126 : if (restrictinfo->mergeopfamilies == NIL)
3631 37832 : continue; /* not mergejoinable */
3632 :
3633 : /*
3634 : * The clause certainly doesn't refer to anything but the given rel.
3635 : * If either side is pseudoconstant then we can use it.
3636 : */
3637 62294 : if (bms_is_empty(restrictinfo->left_relids))
3638 : {
3639 : /* righthand side is inner */
3640 1208 : restrictinfo->outer_is_left = true;
3641 : }
3642 61086 : else if (bms_is_empty(restrictinfo->right_relids))
3643 : {
3644 : /* lefthand side is inner */
3645 61066 : restrictinfo->outer_is_left = false;
3646 : }
3647 : else
3648 20 : continue;
3649 :
3650 : /* OK, add to list */
3651 62274 : restrictlist = lappend(restrictlist, restrictinfo);
3652 : }
3653 :
3654 : /* Short-circuit the easy case */
3655 111258 : if (restrictlist == NIL && exprlist == NIL)
3656 140 : return false;
3657 :
3658 : /* Examine each index of the relation ... */
3659 291642 : foreach(ic, rel->indexlist)
3660 : {
3661 246438 : IndexOptInfo *ind = (IndexOptInfo *) lfirst(ic);
3662 : int c;
3663 :
3664 : /*
3665 : * If the index is not unique, or not immediately enforced, or if it's
3666 : * a partial index that doesn't match the query, it's useless here.
3667 : */
3668 415672 : if (!ind->unique || !ind->immediate ||
3669 169234 : (ind->indpred != NIL && !ind->predOK))
3670 77204 : continue;
3671 :
3672 : /*
3673 : * Try to find each index column in the lists of conditions. This is
3674 : * O(N^2) or worse, but we expect all the lists to be short.
3675 : */
3676 297358 : for (c = 0; c < ind->nkeycolumns; c++)
3677 : {
3678 231444 : bool matched = false;
3679 : ListCell *lc;
3680 : ListCell *lc2;
3681 :
3682 457330 : foreach(lc, restrictlist)
3683 : {
3684 354010 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
3685 : Node *rexpr;
3686 :
3687 : /*
3688 : * The condition's equality operator must be a member of the
3689 : * index opfamily, else it is not asserting the right kind of
3690 : * equality behavior for this index. We check this first
3691 : * since it's probably cheaper than match_index_to_operand().
3692 : */
3693 354010 : if (!list_member_oid(rinfo->mergeopfamilies, ind->opfamily[c]))
3694 91318 : continue;
3695 :
3696 : /*
3697 : * XXX at some point we may need to check collations here too.
3698 : * For the moment we assume all collations reduce to the same
3699 : * notion of equality.
3700 : */
3701 :
3702 : /* OK, see if the condition operand matches the index key */
3703 262692 : if (rinfo->outer_is_left)
3704 126992 : rexpr = get_rightop(rinfo->clause);
3705 : else
3706 135700 : rexpr = get_leftop(rinfo->clause);
3707 :
3708 262692 : if (match_index_to_operand(rexpr, c, ind))
3709 : {
3710 128124 : matched = true; /* column is unique */
3711 128124 : break;
3712 : }
3713 : }
3714 :
3715 231444 : if (matched)
3716 128124 : continue;
3717 :
3718 103320 : forboth(lc, exprlist, lc2, oprlist)
3719 : {
3720 0 : Node *expr = (Node *) lfirst(lc);
3721 0 : Oid opr = lfirst_oid(lc2);
3722 :
3723 : /* See if the expression matches the index key */
3724 0 : if (!match_index_to_operand(expr, c, ind))
3725 0 : continue;
3726 :
3727 : /*
3728 : * The equality operator must be a member of the index
3729 : * opfamily, else it is not asserting the right kind of
3730 : * equality behavior for this index. We assume the caller
3731 : * determined it is an equality operator, so we don't need to
3732 : * check any more tightly than this.
3733 : */
3734 0 : if (!op_in_opfamily(opr, ind->opfamily[c]))
3735 0 : continue;
3736 :
3737 : /*
3738 : * XXX at some point we may need to check collations here too.
3739 : * For the moment we assume all collations reduce to the same
3740 : * notion of equality.
3741 : */
3742 :
3743 0 : matched = true; /* column is unique */
3744 0 : break;
3745 : }
3746 :
3747 103320 : if (!matched)
3748 103320 : break; /* no match; this index doesn't help us */
3749 : }
3750 :
3751 : /* Matched all key columns of this index? */
3752 169234 : if (c == ind->nkeycolumns)
3753 65914 : return true;
3754 : }
3755 :
3756 45204 : return false;
3757 : }
3758 :
3759 : /*
3760 : * indexcol_is_bool_constant_for_query
3761 : *
3762 : * If an index column is constrained to have a constant value by the query's
3763 : * WHERE conditions, then it's irrelevant for sort-order considerations.
3764 : * Usually that means we have a restriction clause WHERE indexcol = constant,
3765 : * which gets turned into an EquivalenceClass containing a constant, which
3766 : * is recognized as redundant by build_index_pathkeys(). But if the index
3767 : * column is a boolean variable (or expression), then we are not going to
3768 : * see WHERE indexcol = constant, because expression preprocessing will have
3769 : * simplified that to "WHERE indexcol" or "WHERE NOT indexcol". So we are not
3770 : * going to have a matching EquivalenceClass (unless the query also contains
3771 : * "ORDER BY indexcol"). To allow such cases to work the same as they would
3772 : * for non-boolean values, this function is provided to detect whether the
3773 : * specified index column matches a boolean restriction clause.
3774 : */
3775 : bool
3776 258620 : indexcol_is_bool_constant_for_query(IndexOptInfo *index, int indexcol)
3777 : {
3778 : ListCell *lc;
3779 :
3780 : /* If the index isn't boolean, we can't possibly get a match */
3781 258620 : if (!IsBooleanOpfamily(index->opfamily[indexcol]))
3782 258404 : return false;
3783 :
3784 : /* Check each restriction clause for the index's rel */
3785 240 : foreach(lc, index->rel->baserestrictinfo)
3786 : {
3787 96 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
3788 :
3789 : /*
3790 : * As in match_clause_to_indexcol, never match pseudoconstants to
3791 : * indexes. (It might be semantically okay to do so here, but the
3792 : * odds of getting a match are negligible, so don't waste the cycles.)
3793 : */
3794 96 : if (rinfo->pseudoconstant)
3795 0 : continue;
3796 :
3797 : /* See if we can match the clause's expression to the index column */
3798 96 : if (match_boolean_index_clause(rinfo, indexcol, index))
3799 72 : return true;
3800 : }
3801 :
3802 144 : return false;
3803 : }
3804 :
3805 :
3806 : /****************************************************************************
3807 : * ---- ROUTINES TO CHECK OPERANDS ----
3808 : ****************************************************************************/
3809 :
3810 : /*
3811 : * match_index_to_operand()
3812 : * Generalized test for a match between an index's key
3813 : * and the operand on one side of a restriction or join clause.
3814 : *
3815 : * operand: the nodetree to be compared to the index
3816 : * indexcol: the column number of the index (counting from 0)
3817 : * index: the index of interest
3818 : *
3819 : * Note that we aren't interested in collations here; the caller must check
3820 : * for a collation match, if it's dealing with an operator where that matters.
3821 : *
3822 : * This is exported for use in selfuncs.c.
3823 : */
3824 : bool
3825 1688822 : match_index_to_operand(Node *operand,
3826 : int indexcol,
3827 : IndexOptInfo *index)
3828 : {
3829 : int indkey;
3830 :
3831 : /*
3832 : * Ignore any RelabelType node above the operand. This is needed to be
3833 : * able to apply indexscanning in binary-compatible-operator cases. Note:
3834 : * we can assume there is at most one RelabelType node;
3835 : * eval_const_expressions() will have simplified if more than one.
3836 : */
3837 1688822 : if (operand && IsA(operand, RelabelType))
3838 13750 : operand = (Node *) ((RelabelType *) operand)->arg;
3839 :
3840 1688822 : indkey = index->indexkeys[indexcol];
3841 1688822 : if (indkey != 0)
3842 : {
3843 : /*
3844 : * Simple index column; operand must be a matching Var.
3845 : */
3846 3006470 : if (operand && IsA(operand, Var) &&
3847 2547168 : index->rel->relid == ((Var *) operand)->varno &&
3848 1226450 : indkey == ((Var *) operand)->varattno)
3849 436764 : return true;
3850 : }
3851 : else
3852 : {
3853 : /*
3854 : * Index expression; find the correct expression. (This search could
3855 : * be avoided, at the cost of complicating all the callers of this
3856 : * routine; doesn't seem worth it.)
3857 : */
3858 : ListCell *indexpr_item;
3859 : int i;
3860 : Node *indexkey;
3861 :
3862 3070 : indexpr_item = list_head(index->indexprs);
3863 3070 : for (i = 0; i < indexcol; i++)
3864 : {
3865 0 : if (index->indexkeys[i] == 0)
3866 : {
3867 0 : if (indexpr_item == NULL)
3868 0 : elog(ERROR, "wrong number of index expressions");
3869 0 : indexpr_item = lnext(indexpr_item);
3870 : }
3871 : }
3872 3070 : if (indexpr_item == NULL)
3873 0 : elog(ERROR, "wrong number of index expressions");
3874 3070 : indexkey = (Node *) lfirst(indexpr_item);
3875 :
3876 : /*
3877 : * Does it match the operand? Again, strip any relabeling.
3878 : */
3879 3070 : if (indexkey && IsA(indexkey, RelabelType))
3880 10 : indexkey = (Node *) ((RelabelType *) indexkey)->arg;
3881 :
3882 3070 : if (equal(indexkey, operand))
3883 1298 : return true;
3884 : }
3885 :
3886 1250760 : return false;
3887 : }
3888 :
3889 : /*
3890 : * is_pseudo_constant_for_index()
3891 : * Test whether the given expression can be used as an indexscan
3892 : * comparison value.
3893 : *
3894 : * An indexscan comparison value must not contain any volatile functions,
3895 : * and it can't contain any Vars of the index's own table. Vars of
3896 : * other tables are okay, though; in that case we'd be producing an
3897 : * indexqual usable in a parameterized indexscan. This is, therefore,
3898 : * a weaker condition than is_pseudo_constant_clause().
3899 : *
3900 : * This function is exported for use by planner support functions,
3901 : * which will have available the IndexOptInfo, but not any RestrictInfo
3902 : * infrastructure. It is making the same test made by functions above
3903 : * such as match_opclause_to_indexcol(), but those rely where possible
3904 : * on RestrictInfo information about variable membership.
3905 : *
3906 : * expr: the nodetree to be checked
3907 : * index: the index of interest
3908 : */
3909 : bool
3910 0 : is_pseudo_constant_for_index(Node *expr, IndexOptInfo *index)
3911 : {
3912 : /* pull_varnos is cheaper than volatility check, so do that first */
3913 0 : if (bms_is_member(index->rel->relid, pull_varnos(expr)))
3914 0 : return false; /* no good, contains Var of table */
3915 0 : if (contain_volatile_functions(expr))
3916 0 : return false; /* no good, volatile comparison value */
3917 0 : return true;
3918 : }
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