PostgreSQL Source Code git master
Loading...
Searching...
No Matches
equivclass.c
Go to the documentation of this file.
1/*-------------------------------------------------------------------------
2 *
3 * equivclass.c
4 * Routines for managing EquivalenceClasses
5 *
6 * See src/backend/optimizer/README for discussion of EquivalenceClasses.
7 *
8 *
9 * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
10 * Portions Copyright (c) 1994, Regents of the University of California
11 *
12 * IDENTIFICATION
13 * src/backend/optimizer/path/equivclass.c
14 *
15 *-------------------------------------------------------------------------
16 */
17#include "postgres.h"
18
19#include <limits.h>
20
21#include "access/stratnum.h"
22#include "catalog/pg_type.h"
23#include "common/hashfn.h"
24#include "nodes/makefuncs.h"
25#include "nodes/nodeFuncs.h"
26#include "optimizer/appendinfo.h"
27#include "optimizer/clauses.h"
28#include "optimizer/optimizer.h"
29#include "optimizer/pathnode.h"
30#include "optimizer/paths.h"
31#include "optimizer/planmain.h"
32#include "optimizer/restrictinfo.h"
33#include "rewrite/rewriteManip.h"
34#include "utils/lsyscache.h"
35
36
37static EquivalenceMember *make_eq_member(EquivalenceClass *ec,
38 Expr *expr, Relids relids,
39 JoinDomain *jdomain,
40 EquivalenceMember *parent,
41 Oid datatype);
42static EquivalenceMember *add_eq_member(EquivalenceClass *ec,
43 Expr *expr, Relids relids,
44 JoinDomain *jdomain,
45 Oid datatype);
46static EquivalenceMember *add_child_eq_member(PlannerInfo *root,
47 EquivalenceClass *ec,
48 int ec_index, Expr *expr,
49 Relids relids,
50 JoinDomain *jdomain,
51 EquivalenceMember *parent_em,
52 Oid datatype,
53 Index child_relid);
54static void generate_base_implied_equalities_const(PlannerInfo *root,
55 EquivalenceClass *ec);
56static void generate_base_implied_equalities_no_const(PlannerInfo *root,
57 EquivalenceClass *ec);
58static void generate_base_implied_equalities_broken(PlannerInfo *root,
59 EquivalenceClass *ec);
60static List *generate_join_implied_equalities_normal(PlannerInfo *root,
61 EquivalenceClass *ec,
62 Relids join_relids,
63 Relids outer_relids,
64 Relids inner_relids);
65static List *generate_join_implied_equalities_broken(PlannerInfo *root,
66 EquivalenceClass *ec,
67 Relids nominal_join_relids,
68 Relids outer_relids,
69 Relids nominal_inner_relids,
70 RelOptInfo *inner_rel);
71static Oid select_equality_operator(EquivalenceClass *ec,
72 Oid lefttype, Oid righttype);
73static RestrictInfo *create_join_clause(PlannerInfo *root,
74 EquivalenceClass *ec, Oid opno,
75 EquivalenceMember *leftem,
76 EquivalenceMember *rightem,
77 EquivalenceClass *parent_ec);
78static bool reconsider_outer_join_clause(PlannerInfo *root,
79 OuterJoinClauseInfo *ojcinfo,
80 bool outer_on_left);
81static bool reconsider_full_join_clause(PlannerInfo *root,
82 OuterJoinClauseInfo *ojcinfo);
83static JoinDomain *find_join_domain(PlannerInfo *root, Relids relids);
84static Bitmapset *get_eclass_indexes_for_relids(PlannerInfo *root,
85 Relids relids);
86static Bitmapset *get_common_eclass_indexes(PlannerInfo *root, Relids relids1,
87 Relids relids2);
88static void ec_build_derives_hash(PlannerInfo *root, EquivalenceClass *ec);
89static void ec_add_derived_clauses(EquivalenceClass *ec, List *clauses);
90static void ec_add_derived_clause(EquivalenceClass *ec, RestrictInfo *clause);
91static void ec_add_clause_to_derives_hash(EquivalenceClass *ec, RestrictInfo *rinfo);
92static RestrictInfo *ec_search_clause_for_ems(PlannerInfo *root, EquivalenceClass *ec,
93 EquivalenceMember *leftem,
94 EquivalenceMember *rightem,
95 EquivalenceClass *parent_ec);
96static RestrictInfo *ec_search_derived_clause_for_ems(PlannerInfo *root,
97 EquivalenceClass *ec,
98 EquivalenceMember *leftem,
99 EquivalenceMember *rightem,
100 EquivalenceClass *parent_ec);
101
102/*
103 * Hash key identifying a derived clause.
104 *
105 * This structure should not be filled manually. Use fill_ec_derives_key() to
106 * set it up in canonical form.
107 */
114
115/* Hash table entry in ec_derives_hash. */
122
123/* Threshold for switching from list to hash table */
124#define EC_DERIVES_HASH_THRESHOLD 32
125
126#define SH_PREFIX derives
127#define SH_ELEMENT_TYPE ECDerivesEntry
128#define SH_KEY_TYPE ECDerivesKey
129#define SH_KEY key
130#define SH_HASH_KEY(tb, key) \
131 hash_bytes((const unsigned char *) &(key), sizeof(ECDerivesKey))
132#define SH_EQUAL(tb, a, b) \
133 ((a).em1 == (b).em1 && (a).em2 == (b).em2 && (a).parent_ec == (b).parent_ec)
134#define SH_SCOPE static inline
135#define SH_DECLARE
136#define SH_DEFINE
137#include "lib/simplehash.h"
138
139/*
140 * process_equivalence
141 * The given clause has a mergejoinable operator and is not an outer-join
142 * qualification, so its two sides can be considered equal
143 * anywhere they are both computable; moreover that equality can be
144 * extended transitively. Record this knowledge in the EquivalenceClass
145 * data structure, if applicable. Returns true if successful, false if not
146 * (in which case caller should treat the clause as ordinary, not an
147 * equivalence).
148 *
149 * In some cases, although we cannot convert a clause into EquivalenceClass
150 * knowledge, we can still modify it to a more useful form than the original.
151 * Then, *p_restrictinfo will be replaced by a new RestrictInfo, which is what
152 * the caller should use for further processing.
153 *
154 * jdomain is the join domain within which the given clause was found.
155 * This limits the applicability of deductions from the EquivalenceClass,
156 * as described in optimizer/README.
157 *
158 * We reject proposed equivalence clauses if they contain leaky functions
159 * and have security_level above zero. The EC evaluation rules require us to
160 * apply certain tests at certain joining levels, and we can't tolerate
161 * delaying any test on security_level grounds. By rejecting candidate clauses
162 * that might require security delays, we ensure it's safe to apply an EC
163 * clause as soon as it's supposed to be applied.
164 *
165 * On success return, we have also initialized the clause's left_ec/right_ec
166 * fields to point to the EquivalenceClass representing it. This saves lookup
167 * effort later.
168 *
169 * Note: constructing merged EquivalenceClasses is a standard UNION-FIND
170 * problem, for which there exist better data structures than simple lists.
171 * If this code ever proves to be a bottleneck then it could be sped up ---
172 * but for now, simple is beautiful.
173 *
174 * Note: this is only called during planner startup, not during GEQO
175 * exploration, so we need not worry about whether we're in the right
176 * memory context.
177 */
178bool
179process_equivalence(PlannerInfo *root,
180 RestrictInfo **p_restrictinfo,
181 JoinDomain *jdomain)
182{
183 RestrictInfo *restrictinfo = *p_restrictinfo;
184 Expr *clause = restrictinfo->clause;
185 Oid opno,
186 collation,
187 item1_type,
188 item2_type;
189 Expr *item1;
190 Expr *item2;
191 Relids item1_relids,
192 item2_relids;
193 List *opfamilies;
194 EquivalenceClass *ec1,
195 *ec2;
196 EquivalenceMember *em1,
197 *em2;
198 ListCell *lc1;
199 int ec2_idx;
200
201 /* Should not already be marked as having generated an eclass */
202 Assert(restrictinfo->left_ec == NULL);
203 Assert(restrictinfo->right_ec == NULL);
204
205 /* Reject if it is potentially postponable by security considerations */
206 if (restrictinfo->security_level > 0 && !restrictinfo->leakproof)
207 return false;
208
209 /* Extract info from given clause */
210 Assert(is_opclause(clause));
211 opno = ((OpExpr *) clause)->opno;
212 collation = ((OpExpr *) clause)->inputcollid;
213 item1 = (Expr *) get_leftop(clause);
214 item2 = (Expr *) get_rightop(clause);
215 item1_relids = restrictinfo->left_relids;
216 item2_relids = restrictinfo->right_relids;
217
218 /*
219 * Ensure both input expressions expose the desired collation (their types
220 * should be OK already); see comments for canonicalize_ec_expression.
221 */
222 item1 = canonicalize_ec_expression(item1,
223 exprType((Node *) item1),
224 collation);
225 item2 = canonicalize_ec_expression(item2,
226 exprType((Node *) item2),
227 collation);
228
229 /*
230 * Clauses of the form X=X cannot be translated into EquivalenceClasses.
231 * We'd either end up with a single-entry EC, losing the knowledge that
232 * the clause was present at all, or else make an EC with duplicate
233 * entries, causing other issues.
234 */
235 if (equal(item1, item2))
236 {
237 /*
238 * If the operator is strict, then the clause can be treated as just
239 * "X IS NOT NULL". (Since we know we are considering a top-level
240 * qual, we can ignore the difference between FALSE and NULL results.)
241 * It's worth making the conversion because we'll typically get a much
242 * better selectivity estimate than we would for X=X.
243 *
244 * If the operator is not strict, we can't be sure what it will do
245 * with NULLs, so don't attempt to optimize it.
246 */
247 set_opfuncid((OpExpr *) clause);
248 if (func_strict(((OpExpr *) clause)->opfuncid))
249 {
250 NullTest *ntest = makeNode(NullTest);
251
252 ntest->arg = item1;
253 ntest->nulltesttype = IS_NOT_NULL;
254 ntest->argisrow = false; /* correct even if composite arg */
255 ntest->location = -1;
256
257 *p_restrictinfo =
258 make_restrictinfo(root,
259 (Expr *) ntest,
260 restrictinfo->is_pushed_down,
261 restrictinfo->has_clone,
262 restrictinfo->is_clone,
263 restrictinfo->pseudoconstant,
264 restrictinfo->security_level,
265 NULL,
266 restrictinfo->incompatible_relids,
267 restrictinfo->outer_relids);
268 }
269 return false;
270 }
271
272 /*
273 * We use the declared input types of the operator, not exprType() of the
274 * inputs, as the nominal datatypes for opfamily lookup. This presumes
275 * that btree operators are always registered with amoplefttype and
276 * amoprighttype equal to their declared input types. We will need this
277 * info anyway to build EquivalenceMember nodes, and by extracting it now
278 * we can use type comparisons to short-circuit some equal() tests.
279 */
280 op_input_types(opno, &item1_type, &item2_type);
281
282 opfamilies = restrictinfo->mergeopfamilies;
283
284 /*
285 * Sweep through the existing EquivalenceClasses looking for matches to
286 * item1 and item2. These are the possible outcomes:
287 *
288 * 1. We find both in the same EC. The equivalence is already known, so
289 * there's nothing to do.
290 *
291 * 2. We find both in different ECs. Merge the two ECs together.
292 *
293 * 3. We find just one. Add the other to its EC.
294 *
295 * 4. We find neither. Make a new, two-entry EC.
296 *
297 * Note: since all ECs are built through this process or the similar
298 * search in get_eclass_for_sort_expr(), it's impossible that we'd match
299 * an item in more than one existing nonvolatile EC. So it's okay to stop
300 * at the first match.
301 */
302 ec1 = ec2 = NULL;
303 em1 = em2 = NULL;
304 ec2_idx = -1;
305 foreach(lc1, root->eq_classes)
306 {
307 EquivalenceClass *cur_ec = (EquivalenceClass *) lfirst(lc1);
308 ListCell *lc2;
309
310 /* Never match to a volatile EC */
311 if (cur_ec->ec_has_volatile)
312 continue;
313
314 /*
315 * The collation has to match; check this first since it's cheaper
316 * than the opfamily comparison.
317 */
318 if (collation != cur_ec->ec_collation)
319 continue;
320
321 /*
322 * A "match" requires matching sets of btree opfamilies. Use of
323 * equal() for this test has implications discussed in the comments
324 * for get_mergejoin_opfamilies().
325 */
326 if (!equal(opfamilies, cur_ec->ec_opfamilies))
327 continue;
328
329 /* We don't expect any children yet */
330 Assert(cur_ec->ec_childmembers == NULL);
331
332 foreach(lc2, cur_ec->ec_members)
333 {
334 EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc2);
335
336 /* Child members should not exist in ec_members */
337 Assert(!cur_em->em_is_child);
338
339 /*
340 * Match constants only within the same JoinDomain (see
341 * optimizer/README).
342 */
343 if (cur_em->em_is_const && cur_em->em_jdomain != jdomain)
344 continue;
345
346 if (!ec1 &&
347 item1_type == cur_em->em_datatype &&
348 equal(item1, cur_em->em_expr))
349 {
350 ec1 = cur_ec;
351 em1 = cur_em;
352 if (ec2)
353 break;
354 }
355
356 if (!ec2 &&
357 item2_type == cur_em->em_datatype &&
358 equal(item2, cur_em->em_expr))
359 {
360 ec2 = cur_ec;
361 ec2_idx = foreach_current_index(lc1);
362 em2 = cur_em;
363 if (ec1)
364 break;
365 }
366 }
367
368 if (ec1 && ec2)
369 break;
370 }
371
372 /* Sweep finished, what did we find? */
373
374 if (ec1 && ec2)
375 {
376 /* If case 1, nothing to do, except add to sources */
377 if (ec1 == ec2)
378 {
379 ec1->ec_sources = lappend(ec1->ec_sources, restrictinfo);
380 ec1->ec_min_security = Min(ec1->ec_min_security,
381 restrictinfo->security_level);
382 ec1->ec_max_security = Max(ec1->ec_max_security,
383 restrictinfo->security_level);
384 /* mark the RI as associated with this eclass */
385 restrictinfo->left_ec = ec1;
386 restrictinfo->right_ec = ec1;
387 /* mark the RI as usable with this pair of EMs */
388 restrictinfo->left_em = em1;
389 restrictinfo->right_em = em2;
390 return true;
391 }
392
393 /*
394 * Case 2: need to merge ec1 and ec2. This should never happen after
395 * the ECs have reached canonical state; otherwise, pathkeys could be
396 * rendered non-canonical by the merge, and relation eclass indexes
397 * would get broken by removal of an eq_classes list entry.
398 */
399 if (root->ec_merging_done)
400 elog(ERROR, "too late to merge equivalence classes");
401
402 /*
403 * We add ec2's items to ec1, then set ec2's ec_merged link to point
404 * to ec1 and remove ec2 from the eq_classes list. We cannot simply
405 * delete ec2 because that could leave dangling pointers in existing
406 * PathKeys. We leave it behind with a link so that the merged EC can
407 * be found.
408 */
409 ec1->ec_members = list_concat(ec1->ec_members, ec2->ec_members);
410 ec1->ec_sources = list_concat(ec1->ec_sources, ec2->ec_sources);
411
412 /*
413 * Appends ec2's derived clauses to ec1->ec_derives_list and adds them
414 * to ec1->ec_derives_hash if present.
415 */
416 ec_add_derived_clauses(ec1, ec2->ec_derives_list);
417 ec1->ec_relids = bms_join(ec1->ec_relids, ec2->ec_relids);
418 ec1->ec_has_const |= ec2->ec_has_const;
419 /* can't need to set has_volatile */
420 ec1->ec_min_security = Min(ec1->ec_min_security,
421 ec2->ec_min_security);
422 ec1->ec_max_security = Max(ec1->ec_max_security,
423 ec2->ec_max_security);
424 ec2->ec_merged = ec1;
425 root->eq_classes = list_delete_nth_cell(root->eq_classes, ec2_idx);
426 /* just to avoid debugging confusion w/ dangling pointers: */
427 ec2->ec_members = NIL;
428 ec2->ec_sources = NIL;
429 ec_clear_derived_clauses(ec2);
430 ec2->ec_relids = NULL;
431 ec1->ec_sources = lappend(ec1->ec_sources, restrictinfo);
432 ec1->ec_min_security = Min(ec1->ec_min_security,
433 restrictinfo->security_level);
434 ec1->ec_max_security = Max(ec1->ec_max_security,
435 restrictinfo->security_level);
436 /* mark the RI as associated with this eclass */
437 restrictinfo->left_ec = ec1;
438 restrictinfo->right_ec = ec1;
439 /* mark the RI as usable with this pair of EMs */
440 restrictinfo->left_em = em1;
441 restrictinfo->right_em = em2;
442 }
443 else if (ec1)
444 {
445 /* Case 3: add item2 to ec1 */
446 em2 = add_eq_member(ec1, item2, item2_relids,
447 jdomain, item2_type);
448 ec1->ec_sources = lappend(ec1->ec_sources, restrictinfo);
449 ec1->ec_min_security = Min(ec1->ec_min_security,
450 restrictinfo->security_level);
451 ec1->ec_max_security = Max(ec1->ec_max_security,
452 restrictinfo->security_level);
453 /* mark the RI as associated with this eclass */
454 restrictinfo->left_ec = ec1;
455 restrictinfo->right_ec = ec1;
456 /* mark the RI as usable with this pair of EMs */
457 restrictinfo->left_em = em1;
458 restrictinfo->right_em = em2;
459 }
460 else if (ec2)
461 {
462 /* Case 3: add item1 to ec2 */
463 em1 = add_eq_member(ec2, item1, item1_relids,
464 jdomain, item1_type);
465 ec2->ec_sources = lappend(ec2->ec_sources, restrictinfo);
466 ec2->ec_min_security = Min(ec2->ec_min_security,
467 restrictinfo->security_level);
468 ec2->ec_max_security = Max(ec2->ec_max_security,
469 restrictinfo->security_level);
470 /* mark the RI as associated with this eclass */
471 restrictinfo->left_ec = ec2;
472 restrictinfo->right_ec = ec2;
473 /* mark the RI as usable with this pair of EMs */
474 restrictinfo->left_em = em1;
475 restrictinfo->right_em = em2;
476 }
477 else
478 {
479 /* Case 4: make a new, two-entry EC */
480 EquivalenceClass *ec = makeNode(EquivalenceClass);
481
482 ec->ec_opfamilies = opfamilies;
483 ec->ec_collation = collation;
484 ec->ec_childmembers_size = 0;
485 ec->ec_members = NIL;
486 ec->ec_childmembers = NULL;
487 ec->ec_sources = list_make1(restrictinfo);
488 ec->ec_derives_list = NIL;
489 ec->ec_derives_hash = NULL;
490 ec->ec_relids = NULL;
491 ec->ec_has_const = false;
492 ec->ec_has_volatile = false;
493 ec->ec_broken = false;
494 ec->ec_sortref = 0;
495 ec->ec_min_security = restrictinfo->security_level;
496 ec->ec_max_security = restrictinfo->security_level;
497 ec->ec_merged = NULL;
498 em1 = add_eq_member(ec, item1, item1_relids,
499 jdomain, item1_type);
500 em2 = add_eq_member(ec, item2, item2_relids,
501 jdomain, item2_type);
502
503 root->eq_classes = lappend(root->eq_classes, ec);
504
505 /* mark the RI as associated with this eclass */
506 restrictinfo->left_ec = ec;
507 restrictinfo->right_ec = ec;
508 /* mark the RI as usable with this pair of EMs */
509 restrictinfo->left_em = em1;
510 restrictinfo->right_em = em2;
511 }
512
513 return true;
514}
515
516/*
517 * canonicalize_ec_expression
518 *
519 * This function ensures that the expression exposes the expected type and
520 * collation, so that it will be equal() to other equivalence-class expressions
521 * that it ought to be equal() to.
522 *
523 * The rule for datatypes is that the exposed type should match what it would
524 * be for an input to an operator of the EC's opfamilies; which is usually
525 * the declared input type of the operator, but in the case of polymorphic
526 * operators no relabeling is wanted (compare the behavior of parse_coerce.c).
527 * Expressions coming in from quals will generally have the right type
528 * already, but expressions coming from indexkeys may not (because they are
529 * represented without any explicit relabel in pg_index), and the same problem
530 * occurs for sort expressions (because the parser is likewise cavalier about
531 * putting relabels on them). Such cases will be binary-compatible with the
532 * real operators, so adding a RelabelType is sufficient.
533 *
534 * Also, the expression's exposed collation must match the EC's collation.
535 * This is important because in comparisons like "foo < bar COLLATE baz",
536 * only one of the expressions has the correct exposed collation as we receive
537 * it from the parser. Forcing both of them to have it ensures that all
538 * variant spellings of such a construct behave the same. Again, we can
539 * stick on a RelabelType to force the right exposed collation. (It might
540 * work to not label the collation at all in EC members, but this is risky
541 * since some parts of the system expect exprCollation() to deliver the
542 * right answer for a sort key.)
543 */
544Expr *
545canonicalize_ec_expression(Expr *expr, Oid req_type, Oid req_collation)
546{
547 Oid expr_type = exprType((Node *) expr);
548
549 /*
550 * For a polymorphic-input-type opclass, just keep the same exposed type.
551 * RECORD opclasses work like polymorphic-type ones for this purpose.
552 */
553 if (IsPolymorphicType(req_type) || req_type == RECORDOID)
554 req_type = expr_type;
555
556 /*
557 * No work if the expression exposes the right type/collation already.
558 */
559 if (expr_type != req_type ||
560 exprCollation((Node *) expr) != req_collation)
561 {
562 /*
563 * If we have to change the type of the expression, set typmod to -1,
564 * since the new type may not have the same typmod interpretation.
565 * When we only have to change collation, preserve the exposed typmod.
566 */
567 int32 req_typmod;
568
569 if (expr_type != req_type)
570 req_typmod = -1;
571 else
572 req_typmod = exprTypmod((Node *) expr);
573
574 /*
575 * Use applyRelabelType so that we preserve const-flatness. This is
576 * important since eval_const_expressions has already been applied.
577 */
578 expr = (Expr *) applyRelabelType((Node *) expr,
579 req_type, req_typmod, req_collation,
580 COERCE_IMPLICIT_CAST, -1, false);
581 }
582
583 return expr;
584}
585
586/*
587 * make_eq_member
588 * Build a new EquivalenceMember without adding it to an EC. If 'parent'
589 * is NULL, the result will be a parent member, otherwise a child member.
590 */
591static EquivalenceMember *
592make_eq_member(EquivalenceClass *ec, Expr *expr, Relids relids,
593 JoinDomain *jdomain, EquivalenceMember *parent, Oid datatype)
594{
595 EquivalenceMember *em = makeNode(EquivalenceMember);
596
597 em->em_expr = expr;
598 em->em_relids = relids;
599 em->em_is_const = false;
600 em->em_is_child = (parent != NULL);
601 em->em_datatype = datatype;
602 em->em_jdomain = jdomain;
603 em->em_parent = parent;
604
605 if (bms_is_empty(relids))
606 {
607 /*
608 * No Vars, assume it's a pseudoconstant. This is correct for entries
609 * generated from process_equivalence(), because a WHERE clause can't
610 * contain aggregates or SRFs, and non-volatility was checked before
611 * process_equivalence() ever got called. But
612 * get_eclass_for_sort_expr() has to work harder. We put the tests
613 * there not here to save cycles in the equivalence case.
614 */
615 Assert(!parent);
616 em->em_is_const = true;
617 ec->ec_has_const = true;
618 /* it can't affect ec_relids */
619 }
620
621 return em;
622}
623
624/*
625 * add_eq_member - build a new non-child EquivalenceMember and add it to 'ec'.
626 */
627static EquivalenceMember *
628add_eq_member(EquivalenceClass *ec, Expr *expr, Relids relids,
629 JoinDomain *jdomain, Oid datatype)
630{
631 EquivalenceMember *em = make_eq_member(ec, expr, relids, jdomain,
632 NULL, datatype);
633
634 /* add to the members list */
635 ec->ec_members = lappend(ec->ec_members, em);
636
637 /* record the relids for parent members */
638 ec->ec_relids = bms_add_members(ec->ec_relids, relids);
639
640 return em;
641}
642
643/*
644 * add_child_eq_member
645 * Create an em_is_child=true EquivalenceMember and add it to 'ec'.
646 *
647 * 'root' is the PlannerInfo that 'ec' belongs to.
648 * 'ec' is the EquivalenceClass to add the child member to.
649 * 'ec_index' the index of 'ec' within root->eq_classes, or -1 if maintaining
650 * the RelOptInfo.eclass_indexes isn't needed.
651 * 'expr' is the em_expr for the new member.
652 * 'relids' is the 'em_relids' for the new member.
653 * 'jdomain' is the 'em_jdomain' for the new member.
654 * 'parent_em' is the parent member of the child to create.
655 * 'datatype' is the em_datatype of the new member.
656 * 'child_relid' defines which element of ec_childmembers to add this member
657 * to. This is generally a RELOPT_OTHER_MEMBER_REL, but for set operations
658 * can be a RELOPT_BASEREL representing the set-op children.
659 */
660static EquivalenceMember *
661add_child_eq_member(PlannerInfo *root, EquivalenceClass *ec, int ec_index,
662 Expr *expr, Relids relids, JoinDomain *jdomain,
663 EquivalenceMember *parent_em, Oid datatype,
664 Index child_relid)
665{
666 EquivalenceMember *em;
667
668 Assert(parent_em != NULL);
669
670 /*
671 * Allocate the array to store child members; an array of Lists indexed by
672 * relid, or expand the existing one, if necessary.
673 */
674 if (unlikely(ec->ec_childmembers_size < root->simple_rel_array_size))
675 {
676 if (ec->ec_childmembers == NULL)
677 ec->ec_childmembers = palloc0_array(List *, root->simple_rel_array_size);
678 else
679 ec->ec_childmembers = repalloc0_array(ec->ec_childmembers, List *,
680 ec->ec_childmembers_size,
681 root->simple_rel_array_size);
682
683 ec->ec_childmembers_size = root->simple_rel_array_size;
684 }
685
686 em = make_eq_member(ec, expr, relids, jdomain, parent_em, datatype);
687
688 /* add member to the ec_childmembers List for the given child_relid */
689 ec->ec_childmembers[child_relid] = lappend(ec->ec_childmembers[child_relid], em);
690
691 /* Record this EC index for the child rel */
692 if (ec_index >= 0)
693 {
694 RelOptInfo *child_rel = root->simple_rel_array[child_relid];
695
696 child_rel->eclass_indexes =
697 bms_add_member(child_rel->eclass_indexes, ec_index);
698 }
699
700 return em;
701}
702
703
704/*
705 * get_eclass_for_sort_expr
706 * Given an expression and opfamily/collation info, find an existing
707 * equivalence class it is a member of; if none, optionally build a new
708 * single-member EquivalenceClass for it.
709 *
710 * sortref is the SortGroupRef of the originating SortGroupClause, if any,
711 * or zero if not. (It should never be zero if the expression is volatile!)
712 *
713 * If rel is not NULL, it identifies a specific relation we're considering
714 * a path for, and indicates that child EC members for that relation can be
715 * considered. Otherwise child members are ignored. (Note: since child EC
716 * members aren't guaranteed unique, a non-NULL value means that there could
717 * be more than one EC that matches the expression; if so it's order-dependent
718 * which one you get. This is annoying but it only happens in corner cases,
719 * so for now we live with just reporting the first match. See also
720 * generate_implied_equalities_for_column and match_pathkeys_to_index.)
721 *
722 * If create_it is true, we'll build a new EquivalenceClass when there is no
723 * match. If create_it is false, we just return NULL when no match.
724 *
725 * This can be used safely both before and after EquivalenceClass merging;
726 * since it never causes merging it does not invalidate any existing ECs
727 * or PathKeys. However, ECs added after path generation has begun are
728 * of limited usefulness, so usually it's best to create them beforehand.
729 *
730 * Note: opfamilies must be chosen consistently with the way
731 * process_equivalence() would do; that is, generated from a mergejoinable
732 * equality operator. Else we might fail to detect valid equivalences,
733 * generating poor (but not incorrect) plans.
734 */
735EquivalenceClass *
736get_eclass_for_sort_expr(PlannerInfo *root,
737 Expr *expr,
738 List *opfamilies,
739 Oid opcintype,
740 Oid collation,
741 Index sortref,
742 Relids rel,
743 bool create_it)
744{
745 JoinDomain *jdomain;
746 Relids expr_relids;
747 EquivalenceClass *newec;
748 EquivalenceMember *newem;
749 ListCell *lc1;
750 MemoryContext oldcontext;
751
752 /*
753 * Ensure the expression exposes the correct type and collation.
754 */
755 expr = canonicalize_ec_expression(expr, opcintype, collation);
756
757 /*
758 * Since SortGroupClause nodes are top-level expressions (GROUP BY, ORDER
759 * BY, etc), they can be presumed to belong to the top JoinDomain.
760 */
761 jdomain = linitial_node(JoinDomain, root->join_domains);
762
763 /*
764 * Scan through the existing EquivalenceClasses for a match
765 */
766 foreach(lc1, root->eq_classes)
767 {
768 EquivalenceClass *cur_ec = (EquivalenceClass *) lfirst(lc1);
769 EquivalenceMemberIterator it;
770 EquivalenceMember *cur_em;
771
772 /*
773 * Never match to a volatile EC, except when we are looking at another
774 * reference to the same volatile SortGroupClause.
775 */
776 if (cur_ec->ec_has_volatile &&
777 (sortref == 0 || sortref != cur_ec->ec_sortref))
778 continue;
779
780 if (collation != cur_ec->ec_collation)
781 continue;
782 if (!equal(opfamilies, cur_ec->ec_opfamilies))
783 continue;
784
785 setup_eclass_member_iterator(&it, cur_ec, rel);
786 while ((cur_em = eclass_member_iterator_next(&it)) != NULL)
787 {
788 /*
789 * Ignore child members unless they match the request.
790 */
791 if (cur_em->em_is_child &&
792 !bms_equal(cur_em->em_relids, rel))
793 continue;
794
795 /*
796 * Match constants only within the same JoinDomain (see
797 * optimizer/README).
798 */
799 if (cur_em->em_is_const && cur_em->em_jdomain != jdomain)
800 continue;
801
802 if (opcintype == cur_em->em_datatype &&
803 equal(expr, cur_em->em_expr))
804 return cur_ec; /* Match! */
805 }
806 }
807
808 /* No match; does caller want a NULL result? */
809 if (!create_it)
810 return NULL;
811
812 /*
813 * OK, build a new single-member EC
814 *
815 * Here, we must be sure that we construct the EC in the right context.
816 */
817 oldcontext = MemoryContextSwitchTo(root->planner_cxt);
818
819 newec = makeNode(EquivalenceClass);
820 newec->ec_opfamilies = list_copy(opfamilies);
821 newec->ec_collation = collation;
822 newec->ec_childmembers_size = 0;
823 newec->ec_members = NIL;
824 newec->ec_childmembers = NULL;
825 newec->ec_sources = NIL;
826 newec->ec_derives_list = NIL;
827 newec->ec_derives_hash = NULL;
828 newec->ec_relids = NULL;
829 newec->ec_has_const = false;
830 newec->ec_has_volatile = contain_volatile_functions((Node *) expr);
831 newec->ec_broken = false;
832 newec->ec_sortref = sortref;
833 newec->ec_min_security = UINT_MAX;
834 newec->ec_max_security = 0;
835 newec->ec_merged = NULL;
836
837 if (newec->ec_has_volatile && sortref == 0) /* should not happen */
838 elog(ERROR, "volatile EquivalenceClass has no sortref");
839
840 /*
841 * Get the precise set of relids appearing in the expression.
842 */
843 expr_relids = pull_varnos(root, (Node *) expr);
844
845 newem = add_eq_member(newec, copyObject(expr), expr_relids,
846 jdomain, opcintype);
847
848 /*
849 * add_eq_member doesn't check for volatile functions, set-returning
850 * functions, aggregates, or window functions, but such could appear in
851 * sort expressions; so we have to check whether its const-marking was
852 * correct.
853 */
854 if (newec->ec_has_const)
855 {
856 if (newec->ec_has_volatile ||
857 expression_returns_set((Node *) expr) ||
858 contain_agg_clause((Node *) expr) ||
859 contain_window_function((Node *) expr))
860 {
861 newec->ec_has_const = false;
862 newem->em_is_const = false;
863 }
864 }
865
866 root->eq_classes = lappend(root->eq_classes, newec);
867
868 /*
869 * If EC merging is already complete, we have to mop up by adding the new
870 * EC to the eclass_indexes of the relation(s) mentioned in it.
871 */
872 if (root->ec_merging_done)
873 {
874 int ec_index = list_length(root->eq_classes) - 1;
875 int i = -1;
876
877 while ((i = bms_next_member(newec->ec_relids, i)) > 0)
878 {
879 RelOptInfo *rel = root->simple_rel_array[i];
880
881 /* ignore the RTE_GROUP RTE */
882 if (i == root->group_rtindex)
883 continue;
884
885 if (rel == NULL) /* must be an outer join */
886 {
887 Assert(bms_is_member(i, root->outer_join_rels));
888 continue;
889 }
890
891 Assert(rel->reloptkind == RELOPT_BASEREL);
892
893 rel->eclass_indexes = bms_add_member(rel->eclass_indexes,
894 ec_index);
895 }
896 }
897
898 MemoryContextSwitchTo(oldcontext);
899
900 return newec;
901}
902
903/*
904 * find_ec_member_matching_expr
905 * Locate an EquivalenceClass member matching the given expr, if any;
906 * return NULL if no match.
907 *
908 * "Matching" is defined as "equal after stripping RelabelTypes".
909 * This is used for identifying sort expressions, and we need to allow
910 * binary-compatible relabeling for some cases involving binary-compatible
911 * sort operators.
912 *
913 * Child EC members are ignored unless they belong to given 'relids'.
914 */
915EquivalenceMember *
916find_ec_member_matching_expr(EquivalenceClass *ec,
917 Expr *expr,
918 Relids relids)
919{
920 EquivalenceMemberIterator it;
921 EquivalenceMember *em;
922
923 /* We ignore binary-compatible relabeling on both ends */
924 while (expr && IsA(expr, RelabelType))
925 expr = ((RelabelType *) expr)->arg;
926
927 setup_eclass_member_iterator(&it, ec, relids);
928 while ((em = eclass_member_iterator_next(&it)) != NULL)
929 {
930 Expr *emexpr;
931
932 /*
933 * We shouldn't be trying to sort by an equivalence class that
934 * contains a constant, so no need to consider such cases any further.
935 */
936 if (em->em_is_const)
937 continue;
938
939 /*
940 * Ignore child members unless they belong to the requested rel.
941 */
942 if (em->em_is_child &&
943 !bms_is_subset(em->em_relids, relids))
944 continue;
945
946 /*
947 * Match if same expression (after stripping relabel).
948 */
949 emexpr = em->em_expr;
950 while (emexpr && IsA(emexpr, RelabelType))
951 emexpr = ((RelabelType *) emexpr)->arg;
952
953 if (equal(emexpr, expr))
954 return em;
955 }
956
957 return NULL;
958}
959
960/*
961 * find_computable_ec_member
962 * Locate an EquivalenceClass member that can be computed from the
963 * expressions appearing in "exprs"; return NULL if no match.
964 *
965 * "exprs" can be either a list of bare expression trees, or a list of
966 * TargetEntry nodes. Typically it will contain Vars and possibly Aggrefs
967 * and WindowFuncs; however, when considering an appendrel member the list
968 * could contain arbitrary expressions. We consider an EC member to be
969 * computable if all the Vars, PlaceHolderVars, Aggrefs, and WindowFuncs
970 * it needs are present in "exprs".
971 *
972 * There is some subtlety in that definition: for example, if an EC member is
973 * Var_A + 1 while what is in "exprs" is Var_A + 2, it's still computable.
974 * This works because in the final plan tree, the EC member's expression will
975 * be computed as part of the same plan node targetlist that is currently
976 * represented by "exprs". So if we have Var_A available for the existing
977 * tlist member, it must be OK to use it in the EC expression too.
978 *
979 * Unlike find_ec_member_matching_expr, there's no special provision here
980 * for binary-compatible relabeling. This is intentional: if we have to
981 * compute an expression in this way, setrefs.c is going to insist on exact
982 * matches of Vars to the source tlist.
983 *
984 * Child EC members are ignored unless they belong to given 'relids'.
985 * Also, non-parallel-safe expressions are ignored if 'require_parallel_safe'.
986 *
987 * Note: some callers pass root == NULL for notational reasons. This is OK
988 * when require_parallel_safe is false.
989 */
990EquivalenceMember *
991find_computable_ec_member(PlannerInfo *root,
992 EquivalenceClass *ec,
993 List *exprs,
994 Relids relids,
995 bool require_parallel_safe)
996{
997 List *exprvars;
998 EquivalenceMemberIterator it;
999 EquivalenceMember *em;
1000
1001 /*
1002 * Pull out the Vars and quasi-Vars present in "exprs". In the typical
1003 * non-appendrel case, this is just another representation of the same
1004 * list. However, it does remove the distinction between the case of a
1005 * list of plain expressions and a list of TargetEntrys.
1006 */
1007 exprvars = pull_var_clause((Node *) exprs,
1008 PVC_INCLUDE_AGGREGATES |
1009 PVC_INCLUDE_WINDOWFUNCS |
1010 PVC_INCLUDE_PLACEHOLDERS);
1011
1012 setup_eclass_member_iterator(&it, ec, relids);
1013 while ((em = eclass_member_iterator_next(&it)) != NULL)
1014 {
1015 List *emvars;
1016 ListCell *lc2;
1017
1018 /*
1019 * We shouldn't be trying to sort by an equivalence class that
1020 * contains a constant, so no need to consider such cases any further.
1021 */
1022 if (em->em_is_const)
1023 continue;
1024
1025 /*
1026 * Ignore child members unless they belong to the requested rel.
1027 */
1028 if (em->em_is_child &&
1029 !bms_is_subset(em->em_relids, relids))
1030 continue;
1031
1032 /*
1033 * Match if all Vars and quasi-Vars are present in "exprs".
1034 */
1035 emvars = pull_var_clause((Node *) em->em_expr,
1036 PVC_INCLUDE_AGGREGATES |
1037 PVC_INCLUDE_WINDOWFUNCS |
1038 PVC_INCLUDE_PLACEHOLDERS);
1039 foreach(lc2, emvars)
1040 {
1041 if (!list_member(exprvars, lfirst(lc2)))
1042 break;
1043 }
1044 list_free(emvars);
1045 if (lc2)
1046 continue; /* we hit a non-available Var */
1047
1048 /*
1049 * If requested, reject expressions that are not parallel-safe. We
1050 * check this last because it's a rather expensive test.
1051 */
1052 if (require_parallel_safe &&
1053 !is_parallel_safe(root, (Node *) em->em_expr))
1054 continue;
1055
1056 return em; /* found usable expression */
1057 }
1058
1059 return NULL;
1060}
1061
1062/*
1063 * relation_can_be_sorted_early
1064 * Can this relation be sorted on this EC before the final output step?
1065 *
1066 * To succeed, we must find an EC member that prepare_sort_from_pathkeys knows
1067 * how to sort on, given the rel's reltarget as input. There are also a few
1068 * additional constraints based on the fact that the desired sort will be done
1069 * "early", within the scan/join part of the plan. Also, non-parallel-safe
1070 * expressions are ignored if 'require_parallel_safe'.
1071 *
1072 * At some point we might want to return the identified EquivalenceMember,
1073 * but for now, callers only want to know if there is one.
1074 */
1075bool
1076relation_can_be_sorted_early(PlannerInfo *root, RelOptInfo *rel,
1077 EquivalenceClass *ec, bool require_parallel_safe)
1078{
1079 PathTarget *target = rel->reltarget;
1080 EquivalenceMember *em;
1081 ListCell *lc;
1082
1083 /*
1084 * Reject volatile ECs immediately; such sorts must always be postponed.
1085 */
1086 if (ec->ec_has_volatile)
1087 return false;
1088
1089 /*
1090 * Try to find an EM directly matching some reltarget member.
1091 */
1092 foreach(lc, target->exprs)
1093 {
1094 Expr *targetexpr = (Expr *) lfirst(lc);
1095
1096 em = find_ec_member_matching_expr(ec, targetexpr, rel->relids);
1097 if (!em)
1098 continue;
1099
1100 /*
1101 * Reject expressions involving set-returning functions, as those
1102 * can't be computed early either. (Note: this test and the following
1103 * one are effectively checking properties of targetexpr, so there's
1104 * no point in asking whether some other EC member would be better.)
1105 */
1106 if (expression_returns_set((Node *) em->em_expr))
1107 continue;
1108
1109 /*
1110 * If requested, reject expressions that are not parallel-safe. We
1111 * check this last because it's a rather expensive test.
1112 */
1113 if (require_parallel_safe &&
1114 !is_parallel_safe(root, (Node *) em->em_expr))
1115 continue;
1116
1117 return true;
1118 }
1119
1120 /*
1121 * Try to find an expression computable from the reltarget.
1122 */
1123 em = find_computable_ec_member(root, ec, target->exprs, rel->relids,
1124 require_parallel_safe);
1125 if (!em)
1126 return false;
1127
1128 /*
1129 * Reject expressions involving set-returning functions, as those can't be
1130 * computed early either. (There's no point in looking for another EC
1131 * member in this case; since SRFs can't appear in WHERE, they cannot
1132 * belong to multi-member ECs.)
1133 */
1134 if (expression_returns_set((Node *) em->em_expr))
1135 return false;
1136
1137 return true;
1138}
1139
1140/*
1141 * generate_base_implied_equalities
1142 * Generate any restriction clauses that we can deduce from equivalence
1143 * classes.
1144 *
1145 * When an EC contains pseudoconstants, our strategy is to generate
1146 * "member = const1" clauses where const1 is the first constant member, for
1147 * every other member (including other constants). If we are able to do this
1148 * then we don't need any "var = var" comparisons because we've successfully
1149 * constrained all the vars at their points of creation. If we fail to
1150 * generate any of these clauses due to lack of cross-type operators, we fall
1151 * back to the "ec_broken" strategy described below. (XXX if there are
1152 * multiple constants of different types, it's possible that we might succeed
1153 * in forming all the required clauses if we started from a different const
1154 * member; but this seems a sufficiently hokey corner case to not be worth
1155 * spending lots of cycles on.)
1156 *
1157 * For ECs that contain no pseudoconstants, we generate derived clauses
1158 * "member1 = member2" for each pair of members belonging to the same base
1159 * relation (actually, if there are more than two for the same base relation,
1160 * we only need enough clauses to link each to each other). This provides
1161 * the base case for the recursion: each row emitted by a base relation scan
1162 * will constrain all computable members of the EC to be equal. As each
1163 * join path is formed, we'll add additional derived clauses on-the-fly
1164 * to maintain this invariant (see generate_join_implied_equalities).
1165 *
1166 * If the opfamilies used by the EC do not provide complete sets of cross-type
1167 * equality operators, it is possible that we will fail to generate a clause
1168 * that must be generated to maintain the invariant. (An example: given
1169 * "WHERE a.x = b.y AND b.y = a.z", the scheme breaks down if we cannot
1170 * generate "a.x = a.z" as a restriction clause for A.) In this case we mark
1171 * the EC "ec_broken" and fall back to regurgitating its original source
1172 * RestrictInfos at appropriate times. We do not try to retract any derived
1173 * clauses already generated from the broken EC, so the resulting plan could
1174 * be poor due to bad selectivity estimates caused by redundant clauses. But
1175 * the correct solution to that is to fix the opfamilies ...
1176 *
1177 * Equality clauses derived by this function are passed off to
1178 * process_implied_equality (in plan/initsplan.c) to be inserted into the
1179 * restrictinfo datastructures. Note that this must be called after initial
1180 * scanning of the quals and before Path construction begins.
1181 *
1182 * We make no attempt to avoid generating duplicate RestrictInfos here: we
1183 * don't search existing source or derived clauses in the EC for matches. It
1184 * doesn't really seem worth the trouble to do so.
1185 */
1186void
1187generate_base_implied_equalities(PlannerInfo *root)
1188{
1189 int ec_index;
1190 ListCell *lc;
1191
1192 /*
1193 * At this point, we're done absorbing knowledge of equivalences in the
1194 * query, so no further EC merging should happen, and ECs remaining in the
1195 * eq_classes list can be considered canonical. (But note that it's still
1196 * possible for new single-member ECs to be added through
1197 * get_eclass_for_sort_expr().)
1198 */
1199 root->ec_merging_done = true;
1200
1201 ec_index = 0;
1202 foreach(lc, root->eq_classes)
1203 {
1204 EquivalenceClass *ec = (EquivalenceClass *) lfirst(lc);
1205 bool can_generate_joinclause = false;
1206 int i;
1207
1208 Assert(ec->ec_merged == NULL); /* else shouldn't be in list */
1209 Assert(!ec->ec_broken); /* not yet anyway... */
1210
1211 /*
1212 * Generate implied equalities that are restriction clauses.
1213 * Single-member ECs won't generate any deductions, either here or at
1214 * the join level.
1215 */
1216 if (list_length(ec->ec_members) > 1)
1217 {
1218 if (ec->ec_has_const)
1219 generate_base_implied_equalities_const(root, ec);
1220 else
1221 generate_base_implied_equalities_no_const(root, ec);
1222
1223 /* Recover if we failed to generate required derived clauses */
1224 if (ec->ec_broken)
1225 generate_base_implied_equalities_broken(root, ec);
1226
1227 /* Detect whether this EC might generate join clauses */
1228 can_generate_joinclause =
1229 (bms_membership(ec->ec_relids) == BMS_MULTIPLE);
1230 }
1231
1232 /*
1233 * Mark the base rels cited in each eclass (which should all exist by
1234 * now) with the eq_classes indexes of all eclasses mentioning them.
1235 * This will let us avoid searching in subsequent lookups. While
1236 * we're at it, we can mark base rels that have pending eclass joins;
1237 * this is a cheap version of has_relevant_eclass_joinclause().
1238 */
1239 i = -1;
1240 while ((i = bms_next_member(ec->ec_relids, i)) > 0)
1241 {
1242 RelOptInfo *rel = root->simple_rel_array[i];
1243
1244 /* ignore the RTE_GROUP RTE */
1245 if (i == root->group_rtindex)
1246 continue;
1247
1248 if (rel == NULL) /* must be an outer join */
1249 {
1250 Assert(bms_is_member(i, root->outer_join_rels));
1251 continue;
1252 }
1253
1254 Assert(rel->reloptkind == RELOPT_BASEREL);
1255
1256 rel->eclass_indexes = bms_add_member(rel->eclass_indexes,
1257 ec_index);
1258
1259 if (can_generate_joinclause)
1260 rel->has_eclass_joins = true;
1261 }
1262
1263 ec_index++;
1264 }
1265}
1266
1267/*
1268 * generate_base_implied_equalities when EC contains pseudoconstant(s)
1269 */
1270static void
1271generate_base_implied_equalities_const(PlannerInfo *root,
1272 EquivalenceClass *ec)
1273{
1274 EquivalenceMember *const_em = NULL;
1275 ListCell *lc;
1276
1277 /*
1278 * In the trivial case where we just had one "var = const" clause, push
1279 * the original clause back into the main planner machinery. There is
1280 * nothing to be gained by doing it differently, and we save the effort to
1281 * re-build and re-analyze an equality clause that will be exactly
1282 * equivalent to the old one.
1283 */
1284 if (list_length(ec->ec_members) == 2 &&
1285 list_length(ec->ec_sources) == 1)
1286 {
1287 RestrictInfo *restrictinfo = (RestrictInfo *) linitial(ec->ec_sources);
1288
1289 distribute_restrictinfo_to_rels(root, restrictinfo);
1290 return;
1291 }
1292
1293 /* We don't expect any children yet */
1294 Assert(ec->ec_childmembers == NULL);
1295
1296 /*
1297 * Find the constant member to use. We prefer an actual constant to
1298 * pseudo-constants (such as Params), because the constraint exclusion
1299 * machinery might be able to exclude relations on the basis of generated
1300 * "var = const" equalities, but "var = param" won't work for that.
1301 */
1302 foreach(lc, ec->ec_members)
1303 {
1304 EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc);
1305
1306 if (cur_em->em_is_const)
1307 {
1308 const_em = cur_em;
1309 if (IsA(cur_em->em_expr, Const))
1310 break;
1311 }
1312 }
1313 Assert(const_em != NULL);
1314
1315 /* Generate a derived equality against each other member */
1316 foreach(lc, ec->ec_members)
1317 {
1318 EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc);
1319 Oid eq_op;
1320 RestrictInfo *rinfo;
1321
1322 /* Child members should not exist in ec_members */
1323 Assert(!cur_em->em_is_child);
1324 if (cur_em == const_em)
1325 continue;
1326 eq_op = select_equality_operator(ec,
1327 cur_em->em_datatype,
1328 const_em->em_datatype);
1329 if (!OidIsValid(eq_op))
1330 {
1331 /* failed... */
1332 ec->ec_broken = true;
1333 break;
1334 }
1335
1336 /*
1337 * We use the constant's em_jdomain as qualscope, so that if the
1338 * generated clause is variable-free (i.e, both EMs are consts) it
1339 * will be enforced at the join domain level.
1340 */
1341 rinfo = process_implied_equality(root, eq_op, ec->ec_collation,
1342 cur_em->em_expr, const_em->em_expr,
1343 const_em->em_jdomain->jd_relids,
1344 ec->ec_min_security,
1345 cur_em->em_is_const);
1346
1347 /*
1348 * If the clause didn't degenerate to a constant, fill in the correct
1349 * markings for a mergejoinable clause, and save it as a derived
1350 * clause. (We will not re-use such clauses directly, but selectivity
1351 * estimation may consult those later. Note that this use of derived
1352 * clauses does not overlap with its use for join clauses, since we
1353 * never generate join clauses from an ec_has_const eclass.)
1354 */
1355 if (rinfo && rinfo->mergeopfamilies)
1356 {
1357 /* it's not redundant, so don't set parent_ec */
1358 rinfo->left_ec = rinfo->right_ec = ec;
1359 rinfo->left_em = cur_em;
1360 rinfo->right_em = const_em;
1361 ec_add_derived_clause(ec, rinfo);
1362 }
1363 }
1364}
1365
1366/*
1367 * generate_base_implied_equalities when EC contains no pseudoconstants
1368 */
1369static void
1370generate_base_implied_equalities_no_const(PlannerInfo *root,
1371 EquivalenceClass *ec)
1372{
1373 EquivalenceMember **prev_ems;
1374 ListCell *lc;
1375
1376 /*
1377 * We scan the EC members once and track the last-seen member for each
1378 * base relation. When we see another member of the same base relation,
1379 * we generate "prev_em = cur_em". This results in the minimum number of
1380 * derived clauses, but it's possible that it will fail when a different
1381 * ordering would succeed. XXX FIXME: use a UNION-FIND algorithm similar
1382 * to the way we build merged ECs. (Use a list-of-lists for each rel.)
1383 */
1384 prev_ems = (EquivalenceMember **)
1385 palloc0(root->simple_rel_array_size * sizeof(EquivalenceMember *));
1386
1387 /* We don't expect any children yet */
1388 Assert(ec->ec_childmembers == NULL);
1389
1390 foreach(lc, ec->ec_members)
1391 {
1392 EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc);
1393 int relid;
1394
1395 /* Child members should not exist in ec_members */
1396 Assert(!cur_em->em_is_child);
1397
1398 if (!bms_get_singleton_member(cur_em->em_relids, &relid))
1399 continue;
1400 Assert(relid < root->simple_rel_array_size);
1401
1402 if (prev_ems[relid] != NULL)
1403 {
1404 EquivalenceMember *prev_em = prev_ems[relid];
1405 Oid eq_op;
1406 RestrictInfo *rinfo;
1407
1408 eq_op = select_equality_operator(ec,
1409 prev_em->em_datatype,
1410 cur_em->em_datatype);
1411 if (!OidIsValid(eq_op))
1412 {
1413 /* failed... */
1414 ec->ec_broken = true;
1415 break;
1416 }
1417
1418 /*
1419 * The expressions aren't constants, so the passed qualscope will
1420 * never be used to place the generated clause. We just need to
1421 * be sure it covers both expressions, which em_relids should do.
1422 */
1423 rinfo = process_implied_equality(root, eq_op, ec->ec_collation,
1424 prev_em->em_expr, cur_em->em_expr,
1425 cur_em->em_relids,
1426 ec->ec_min_security,
1427 false);
1428
1429 /*
1430 * If the clause didn't degenerate to a constant, fill in the
1431 * correct markings for a mergejoinable clause. We don't record
1432 * it as a derived clause, since we don't currently need to
1433 * re-find such clauses, and don't want to clutter the
1434 * derived-clause set with non-join clauses.
1435 */
1436 if (rinfo && rinfo->mergeopfamilies)
1437 {
1438 /* it's not redundant, so don't set parent_ec */
1439 rinfo->left_ec = rinfo->right_ec = ec;
1440 rinfo->left_em = prev_em;
1441 rinfo->right_em = cur_em;
1442 }
1443 }
1444 prev_ems[relid] = cur_em;
1445 }
1446
1447 pfree(prev_ems);
1448
1449 /*
1450 * We also have to make sure that all the Vars used in the member clauses
1451 * will be available at any join node we might try to reference them at.
1452 * For the moment we force all the Vars to be available at all join nodes
1453 * for this eclass. Perhaps this could be improved by doing some
1454 * pre-analysis of which members we prefer to join, but it's no worse than
1455 * what happened in the pre-8.3 code. (Note: rebuild_eclass_attr_needed
1456 * needs to match this code.)
1457 */
1458 foreach(lc, ec->ec_members)
1459 {
1460 EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc);
1461 List *vars = pull_var_clause((Node *) cur_em->em_expr,
1462 PVC_RECURSE_AGGREGATES |
1463 PVC_RECURSE_WINDOWFUNCS |
1464 PVC_INCLUDE_PLACEHOLDERS);
1465
1466 add_vars_to_targetlist(root, vars, ec->ec_relids);
1467 list_free(vars);
1468 }
1469}
1470
1471/*
1472 * generate_base_implied_equalities cleanup after failure
1473 *
1474 * What we must do here is push any zero- or one-relation source RestrictInfos
1475 * of the EC back into the main restrictinfo datastructures. Multi-relation
1476 * clauses will be regurgitated later by generate_join_implied_equalities().
1477 * (We do it this way to maintain continuity with the case that ec_broken
1478 * becomes set only after we've gone up a join level or two.) However, for
1479 * an EC that contains constants, we can adopt a simpler strategy and just
1480 * throw back all the source RestrictInfos immediately; that works because
1481 * we know that such an EC can't become broken later. (This rule justifies
1482 * ignoring ec_has_const ECs in generate_join_implied_equalities, even when
1483 * they are broken.)
1484 */
1485static void
1486generate_base_implied_equalities_broken(PlannerInfo *root,
1487 EquivalenceClass *ec)
1488{
1489 ListCell *lc;
1490
1491 foreach(lc, ec->ec_sources)
1492 {
1493 RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(lc);
1494
1495 if (ec->ec_has_const ||
1496 bms_membership(restrictinfo->required_relids) != BMS_MULTIPLE)
1497 distribute_restrictinfo_to_rels(root, restrictinfo);
1498 }
1499}
1500
1501
1502/*
1503 * generate_join_implied_equalities
1504 * Generate any join clauses that we can deduce from equivalence classes.
1505 *
1506 * At a join node, we must enforce restriction clauses sufficient to ensure
1507 * that all equivalence-class members computable at that node are equal.
1508 * Since the set of clauses to enforce can vary depending on which subset
1509 * relations are the inputs, we have to compute this afresh for each join
1510 * relation pair. Hence a fresh List of RestrictInfo nodes is built and
1511 * passed back on each call.
1512 *
1513 * In addition to its use at join nodes, this can be applied to generate
1514 * eclass-based join clauses for use in a parameterized scan of a base rel.
1515 * The reason for the asymmetry of specifying the inner rel as a RelOptInfo
1516 * and the outer rel by Relids is that this usage occurs before we have
1517 * built any join RelOptInfos.
1518 *
1519 * An annoying special case for parameterized scans is that the inner rel can
1520 * be an appendrel child (an "other rel"). In this case we must generate
1521 * appropriate clauses using child EC members. add_child_rel_equivalences
1522 * must already have been done for the child rel.
1523 *
1524 * The results are sufficient for use in merge, hash, and plain nestloop join
1525 * methods. We do not worry here about selecting clauses that are optimal
1526 * for use in a parameterized indexscan. indxpath.c makes its own selections
1527 * of clauses to use, and if the ones we pick here are redundant with those,
1528 * the extras will be eliminated at createplan time, using the parent_ec
1529 * markers that we provide (see is_redundant_derived_clause()).
1530 *
1531 * Because the same join clauses are likely to be needed multiple times as
1532 * we consider different join paths, we avoid generating multiple copies:
1533 * whenever we select a particular pair of EquivalenceMembers to join,
1534 * we check to see if the pair matches any original clause (in ec_sources)
1535 * or previously-built derived clause. This saves memory and allows
1536 * re-use of information cached in RestrictInfos. We also avoid generating
1537 * commutative duplicates, i.e. if the algorithm selects "a.x = b.y" but
1538 * we already have "b.y = a.x", we return the existing clause.
1539 *
1540 * If we are considering an outer join, sjinfo is the associated OJ info,
1541 * otherwise it can be NULL.
1542 *
1543 * join_relids should always equal bms_union(outer_relids, inner_rel->relids)
1544 * plus whatever add_outer_joins_to_relids() would add. We could simplify
1545 * this function's API by computing it internally, but most callers have the
1546 * value at hand anyway.
1547 */
1548List *
1549generate_join_implied_equalities(PlannerInfo *root,
1550 Relids join_relids,
1551 Relids outer_relids,
1552 RelOptInfo *inner_rel,
1553 SpecialJoinInfo *sjinfo)
1554{
1555 List *result = NIL;
1556 Relids inner_relids = inner_rel->relids;
1557 Relids nominal_inner_relids;
1558 Relids nominal_join_relids;
1559 Bitmapset *matching_ecs;
1560 int i;
1561
1562 /* If inner rel is a child, extra setup work is needed */
1563 if (IS_OTHER_REL(inner_rel))
1564 {
1565 Assert(!bms_is_empty(inner_rel->top_parent_relids));
1566
1567 /* Fetch relid set for the topmost parent rel */
1568 nominal_inner_relids = inner_rel->top_parent_relids;
1569 /* ECs will be marked with the parent's relid, not the child's */
1570 nominal_join_relids = bms_union(outer_relids, nominal_inner_relids);
1571 nominal_join_relids = add_outer_joins_to_relids(root,
1572 nominal_join_relids,
1573 sjinfo,
1574 NULL);
1575 }
1576 else
1577 {
1578 nominal_inner_relids = inner_relids;
1579 nominal_join_relids = join_relids;
1580 }
1581
1582 /*
1583 * Examine all potentially-relevant eclasses.
1584 *
1585 * If we are considering an outer join, we must include "join" clauses
1586 * that mention either input rel plus the outer join's relid; these
1587 * represent post-join filter clauses that have to be applied at this
1588 * join. We don't have infrastructure that would let us identify such
1589 * eclasses cheaply, so just fall back to considering all eclasses
1590 * mentioning anything in nominal_join_relids.
1591 *
1592 * At inner joins, we can be smarter: only consider eclasses mentioning
1593 * both input rels.
1594 */
1595 if (sjinfo && sjinfo->ojrelid != 0)
1596 matching_ecs = get_eclass_indexes_for_relids(root, nominal_join_relids);
1597 else
1598 matching_ecs = get_common_eclass_indexes(root, nominal_inner_relids,
1599 outer_relids);
1600
1601 i = -1;
1602 while ((i = bms_next_member(matching_ecs, i)) >= 0)
1603 {
1604 EquivalenceClass *ec = (EquivalenceClass *) list_nth(root->eq_classes, i);
1605 List *sublist = NIL;
1606
1607 /* ECs containing consts do not need any further enforcement */
1608 if (ec->ec_has_const)
1609 continue;
1610
1611 /* Single-member ECs won't generate any deductions */
1612 if (list_length(ec->ec_members) <= 1)
1613 continue;
1614
1615 /* Sanity check that this eclass overlaps the join */
1616 Assert(bms_overlap(ec->ec_relids, nominal_join_relids));
1617
1618 if (!ec->ec_broken)
1619 sublist = generate_join_implied_equalities_normal(root,
1620 ec,
1621 join_relids,
1622 outer_relids,
1623 inner_relids);
1624
1625 /* Recover if we failed to generate required derived clauses */
1626 if (ec->ec_broken)
1627 sublist = generate_join_implied_equalities_broken(root,
1628 ec,
1629 nominal_join_relids,
1630 outer_relids,
1631 nominal_inner_relids,
1632 inner_rel);
1633
1634 result = list_concat(result, sublist);
1635 }
1636
1637 return result;
1638}
1639
1640/*
1641 * generate_join_implied_equalities_for_ecs
1642 * As above, but consider only the listed ECs.
1643 *
1644 * For the sole current caller, we can assume sjinfo == NULL, that is we are
1645 * not interested in outer-join filter clauses. This might need to change
1646 * in future.
1647 */
1648List *
1649generate_join_implied_equalities_for_ecs(PlannerInfo *root,
1650 List *eclasses,
1651 Relids join_relids,
1652 Relids outer_relids,
1653 RelOptInfo *inner_rel)
1654{
1655 List *result = NIL;
1656 Relids inner_relids = inner_rel->relids;
1657 Relids nominal_inner_relids;
1658 Relids nominal_join_relids;
1659 ListCell *lc;
1660
1661 /* If inner rel is a child, extra setup work is needed */
1662 if (IS_OTHER_REL(inner_rel))
1663 {
1664 Assert(!bms_is_empty(inner_rel->top_parent_relids));
1665
1666 /* Fetch relid set for the topmost parent rel */
1667 nominal_inner_relids = inner_rel->top_parent_relids;
1668 /* ECs will be marked with the parent's relid, not the child's */
1669 nominal_join_relids = bms_union(outer_relids, nominal_inner_relids);
1670 }
1671 else
1672 {
1673 nominal_inner_relids = inner_relids;
1674 nominal_join_relids = join_relids;
1675 }
1676
1677 foreach(lc, eclasses)
1678 {
1679 EquivalenceClass *ec = (EquivalenceClass *) lfirst(lc);
1680 List *sublist = NIL;
1681
1682 /* ECs containing consts do not need any further enforcement */
1683 if (ec->ec_has_const)
1684 continue;
1685
1686 /* Single-member ECs won't generate any deductions */
1687 if (list_length(ec->ec_members) <= 1)
1688 continue;
1689
1690 /* We can quickly ignore any that don't overlap the join, too */
1691 if (!bms_overlap(ec->ec_relids, nominal_join_relids))
1692 continue;
1693
1694 if (!ec->ec_broken)
1695 sublist = generate_join_implied_equalities_normal(root,
1696 ec,
1697 join_relids,
1698 outer_relids,
1699 inner_relids);
1700
1701 /* Recover if we failed to generate required derived clauses */
1702 if (ec->ec_broken)
1703 sublist = generate_join_implied_equalities_broken(root,
1704 ec,
1705 nominal_join_relids,
1706 outer_relids,
1707 nominal_inner_relids,
1708 inner_rel);
1709
1710 result = list_concat(result, sublist);
1711 }
1712
1713 return result;
1714}
1715
1716/*
1717 * generate_join_implied_equalities for a still-valid EC
1718 */
1719static List *
1720generate_join_implied_equalities_normal(PlannerInfo *root,
1721 EquivalenceClass *ec,
1722 Relids join_relids,
1723 Relids outer_relids,
1724 Relids inner_relids)
1725{
1726 List *result = NIL;
1727 List *new_members = NIL;
1728 List *outer_members = NIL;
1729 List *inner_members = NIL;
1730 EquivalenceMemberIterator it;
1731 EquivalenceMember *cur_em;
1732
1733 /*
1734 * First, scan the EC to identify member values that are computable at the
1735 * outer rel, at the inner rel, or at this relation but not in either
1736 * input rel. The outer-rel members should already be enforced equal,
1737 * likewise for the inner-rel members. We'll need to create clauses to
1738 * enforce that any newly computable members are all equal to each other
1739 * as well as to at least one input member, plus enforce at least one
1740 * outer-rel member equal to at least one inner-rel member.
1741 */
1742 setup_eclass_member_iterator(&it, ec, join_relids);
1743 while ((cur_em = eclass_member_iterator_next(&it)) != NULL)
1744 {
1745 /*
1746 * We don't need to check explicitly for child EC members. This test
1747 * against join_relids will cause them to be ignored except when
1748 * considering a child inner rel, which is what we want.
1749 */
1750 if (!bms_is_subset(cur_em->em_relids, join_relids))
1751 continue; /* not computable yet, or wrong child */
1752
1753 if (bms_is_subset(cur_em->em_relids, outer_relids))
1754 outer_members = lappend(outer_members, cur_em);
1755 else if (bms_is_subset(cur_em->em_relids, inner_relids))
1756 inner_members = lappend(inner_members, cur_em);
1757 else
1758 new_members = lappend(new_members, cur_em);
1759 }
1760
1761 /*
1762 * First, select the joinclause if needed. We can equate any one outer
1763 * member to any one inner member, but we have to find a datatype
1764 * combination for which an opfamily member operator exists. If we have
1765 * choices, we prefer simple Var members (possibly with RelabelType) since
1766 * these are (a) cheapest to compute at runtime and (b) most likely to
1767 * have useful statistics. Also, prefer operators that are also
1768 * hashjoinable.
1769 */
1770 if (outer_members && inner_members)
1771 {
1772 EquivalenceMember *best_outer_em = NULL;
1773 EquivalenceMember *best_inner_em = NULL;
1774 Oid best_eq_op = InvalidOid;
1775 int best_score = -1;
1776 RestrictInfo *rinfo;
1777 ListCell *lc1;
1778
1779 foreach(lc1, outer_members)
1780 {
1781 EquivalenceMember *outer_em = (EquivalenceMember *) lfirst(lc1);
1782 ListCell *lc2;
1783
1784 foreach(lc2, inner_members)
1785 {
1786 EquivalenceMember *inner_em = (EquivalenceMember *) lfirst(lc2);
1787 Oid eq_op;
1788 int score;
1789
1790 eq_op = select_equality_operator(ec,
1791 outer_em->em_datatype,
1792 inner_em->em_datatype);
1793 if (!OidIsValid(eq_op))
1794 continue;
1795 score = 0;
1796 if (IsA(outer_em->em_expr, Var) ||
1797 (IsA(outer_em->em_expr, RelabelType) &&
1798 IsA(((RelabelType *) outer_em->em_expr)->arg, Var)))
1799 score++;
1800 if (IsA(inner_em->em_expr, Var) ||
1801 (IsA(inner_em->em_expr, RelabelType) &&
1802 IsA(((RelabelType *) inner_em->em_expr)->arg, Var)))
1803 score++;
1804 if (op_hashjoinable(eq_op,
1805 exprType((Node *) outer_em->em_expr)))
1806 score++;
1807 if (score > best_score)
1808 {
1809 best_outer_em = outer_em;
1810 best_inner_em = inner_em;
1811 best_eq_op = eq_op;
1812 best_score = score;
1813 if (best_score == 3)
1814 break; /* no need to look further */
1815 }
1816 }
1817 if (best_score == 3)
1818 break; /* no need to look further */
1819 }
1820 if (best_score < 0)
1821 {
1822 /* failed... */
1823 ec->ec_broken = true;
1824 return NIL;
1825 }
1826
1827 /*
1828 * Create clause, setting parent_ec to mark it as redundant with other
1829 * joinclauses
1830 */
1831 rinfo = create_join_clause(root, ec, best_eq_op,
1832 best_outer_em, best_inner_em,
1833 ec);
1834
1835 result = lappend(result, rinfo);
1836 }
1837
1838 /*
1839 * Now deal with building restrictions for any expressions that involve
1840 * Vars from both sides of the join. We have to equate all of these to
1841 * each other as well as to at least one old member (if any).
1842 *
1843 * XXX as in generate_base_implied_equalities_no_const, we could be a lot
1844 * smarter here to avoid unnecessary failures in cross-type situations.
1845 * For now, use the same left-to-right method used there.
1846 */
1847 if (new_members)
1848 {
1849 List *old_members = list_concat(outer_members, inner_members);
1850 EquivalenceMember *prev_em = NULL;
1851 RestrictInfo *rinfo;
1852 ListCell *lc1;
1853
1854 /* For now, arbitrarily take the first old_member as the one to use */
1855 if (old_members)
1856 new_members = lappend(new_members, linitial(old_members));
1857
1858 foreach(lc1, new_members)
1859 {
1860 cur_em = (EquivalenceMember *) lfirst(lc1);
1861
1862 if (prev_em != NULL)
1863 {
1864 Oid eq_op;
1865
1866 eq_op = select_equality_operator(ec,
1867 prev_em->em_datatype,
1868 cur_em->em_datatype);
1869 if (!OidIsValid(eq_op))
1870 {
1871 /* failed... */
1872 ec->ec_broken = true;
1873 return NIL;
1874 }
1875 /* do NOT set parent_ec, this qual is not redundant! */
1876 rinfo = create_join_clause(root, ec, eq_op,
1877 prev_em, cur_em,
1878 NULL);
1879
1880 result = lappend(result, rinfo);
1881 }
1882 prev_em = cur_em;
1883 }
1884 }
1885
1886 return result;
1887}
1888
1889/*
1890 * generate_join_implied_equalities cleanup after failure
1891 *
1892 * Return any original RestrictInfos that are enforceable at this join.
1893 *
1894 * In the case of a child inner relation, we have to translate the
1895 * original RestrictInfos from parent to child Vars.
1896 */
1897static List *
1898generate_join_implied_equalities_broken(PlannerInfo *root,
1899 EquivalenceClass *ec,
1900 Relids nominal_join_relids,
1901 Relids outer_relids,
1902 Relids nominal_inner_relids,
1903 RelOptInfo *inner_rel)
1904{
1905 List *result = NIL;
1906 ListCell *lc;
1907
1908 foreach(lc, ec->ec_sources)
1909 {
1910 RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(lc);
1911 Relids clause_relids = restrictinfo->required_relids;
1912
1913 if (bms_is_subset(clause_relids, nominal_join_relids) &&
1914 !bms_is_subset(clause_relids, outer_relids) &&
1915 !bms_is_subset(clause_relids, nominal_inner_relids))
1916 result = lappend(result, restrictinfo);
1917 }
1918
1919 /*
1920 * If we have to translate, just brute-force apply adjust_appendrel_attrs
1921 * to all the RestrictInfos at once. This will result in returning
1922 * RestrictInfos that are not included in EC's derived clauses, but there
1923 * shouldn't be any duplication, and it's a sufficiently narrow corner
1924 * case that we shouldn't sweat too much over it anyway.
1925 *
1926 * Since inner_rel might be an indirect descendant of the baserel
1927 * mentioned in the ec_sources clauses, we have to be prepared to apply
1928 * multiple levels of Var translation.
1929 */
1930 if (IS_OTHER_REL(inner_rel) && result != NIL)
1931 result = (List *) adjust_appendrel_attrs_multilevel(root,
1932 (Node *) result,
1933 inner_rel,
1934 inner_rel->top_parent);
1935
1936 return result;
1937}
1938
1939
1940/*
1941 * select_equality_operator
1942 * Select a suitable equality operator for comparing two EC members
1943 *
1944 * Returns InvalidOid if no operator can be found for this datatype combination
1945 */
1946static Oid
1947select_equality_operator(EquivalenceClass *ec, Oid lefttype, Oid righttype)
1948{
1949 ListCell *lc;
1950
1951 foreach(lc, ec->ec_opfamilies)
1952 {
1953 Oid opfamily = lfirst_oid(lc);
1954 Oid opno;
1955
1956 opno = get_opfamily_member_for_cmptype(opfamily, lefttype, righttype, COMPARE_EQ);
1957 if (!OidIsValid(opno))
1958 continue;
1959 /* If no barrier quals in query, don't worry about leaky operators */
1960 if (ec->ec_max_security == 0)
1961 return opno;
1962 /* Otherwise, insist that selected operators be leakproof */
1963 if (get_func_leakproof(get_opcode(opno)))
1964 return opno;
1965 }
1966 return InvalidOid;
1967}
1968
1969
1970/*
1971 * create_join_clause
1972 * Find or make a RestrictInfo comparing the two given EC members
1973 * with the given operator (or, possibly, its commutator, because
1974 * the ordering of the operands in the result is not guaranteed).
1975 *
1976 * parent_ec is either equal to ec (if the clause is a potentially-redundant
1977 * join clause) or NULL (if not). We have to treat this as part of the
1978 * match requirements --- it's possible that a clause comparing the same two
1979 * EMs is a join clause in one join path and a restriction clause in another.
1980 */
1981static RestrictInfo *
1982create_join_clause(PlannerInfo *root,
1983 EquivalenceClass *ec, Oid opno,
1984 EquivalenceMember *leftem,
1985 EquivalenceMember *rightem,
1986 EquivalenceClass *parent_ec)
1987{
1988 RestrictInfo *rinfo;
1989 RestrictInfo *parent_rinfo = NULL;
1990 MemoryContext oldcontext;
1991
1992 rinfo = ec_search_clause_for_ems(root, ec, leftem, rightem, parent_ec);
1993 if (rinfo)
1994 return rinfo;
1995
1996 /*
1997 * Not there, so build it, in planner context so we can re-use it. (Not
1998 * important in normal planning, but definitely so in GEQO.)
1999 */
2000 oldcontext = MemoryContextSwitchTo(root->planner_cxt);
2001
2002 /*
2003 * If either EM is a child, recursively create the corresponding
2004 * parent-to-parent clause, so that we can duplicate its rinfo_serial.
2005 */
2006 if (leftem->em_is_child || rightem->em_is_child)
2007 {
2008 EquivalenceMember *leftp = leftem->em_parent ? leftem->em_parent : leftem;
2009 EquivalenceMember *rightp = rightem->em_parent ? rightem->em_parent : rightem;
2010
2011 parent_rinfo = create_join_clause(root, ec, opno,
2012 leftp, rightp,
2013 parent_ec);
2014 }
2015
2016 rinfo = build_implied_join_equality(root,
2017 opno,
2018 ec->ec_collation,
2019 leftem->em_expr,
2020 rightem->em_expr,
2021 bms_union(leftem->em_relids,
2022 rightem->em_relids),
2023 ec->ec_min_security);
2024
2025 /*
2026 * If either EM is a child, force the clause's clause_relids to include
2027 * the relid(s) of the child rel. In normal cases it would already, but
2028 * not if we are considering appendrel child relations with pseudoconstant
2029 * translated variables (i.e., UNION ALL sub-selects with constant output
2030 * items). We must do this so that join_clause_is_movable_into() will
2031 * think that the clause should be evaluated at the correct place.
2032 */
2033 if (leftem->em_is_child)
2034 rinfo->clause_relids = bms_add_members(rinfo->clause_relids,
2035 leftem->em_relids);
2036 if (rightem->em_is_child)
2037 rinfo->clause_relids = bms_add_members(rinfo->clause_relids,
2038 rightem->em_relids);
2039
2040 /* If it's a child clause, copy the parent's rinfo_serial */
2041 if (parent_rinfo)
2042 rinfo->rinfo_serial = parent_rinfo->rinfo_serial;
2043
2044 /* Mark the clause as redundant, or not */
2045 rinfo->parent_ec = parent_ec;
2046
2047 /*
2048 * We know the correct values for left_ec/right_ec, ie this particular EC,
2049 * so we can just set them directly instead of forcing another lookup.
2050 */
2051 rinfo->left_ec = ec;
2052 rinfo->right_ec = ec;
2053
2054 /* Mark it as usable with these EMs */
2055 rinfo->left_em = leftem;
2056 rinfo->right_em = rightem;
2057 /* and save it for possible re-use */
2058 ec_add_derived_clause(ec, rinfo);
2059
2060 MemoryContextSwitchTo(oldcontext);
2061
2062 return rinfo;
2063}
2064
2065
2066/*
2067 * reconsider_outer_join_clauses
2068 * Re-examine any outer-join clauses that were set aside by
2069 * distribute_qual_to_rels(), and see if we can derive any
2070 * EquivalenceClasses from them. Then, if they were not made
2071 * redundant, push them out into the regular join-clause lists.
2072 *
2073 * When we have mergejoinable clauses A = B that are outer-join clauses,
2074 * we can't blindly combine them with other clauses A = C to deduce B = C,
2075 * since in fact the "equality" A = B won't necessarily hold above the
2076 * outer join (one of the variables might be NULL instead). Nonetheless
2077 * there are cases where we can add qual clauses using transitivity.
2078 *
2079 * One case that we look for here is an outer-join clause OUTERVAR = INNERVAR
2080 * for which there is also an equivalence clause OUTERVAR = CONSTANT.
2081 * It is safe and useful to push a clause INNERVAR = CONSTANT into the
2082 * evaluation of the inner (nullable) relation, because any inner rows not
2083 * meeting this condition will not contribute to the outer-join result anyway.
2084 * (Any outer rows they could join to will be eliminated by the pushed-down
2085 * equivalence clause.)
2086 *
2087 * Note that the above rule does not work for full outer joins; nor is it
2088 * very interesting to consider cases where the generated equivalence clause
2089 * would involve relations outside the outer join, since such clauses couldn't
2090 * be pushed into the inner side's scan anyway. So the restriction to
2091 * outervar = pseudoconstant is not really giving up anything.
2092 *
2093 * For full-join cases, we can only do something useful if it's a FULL JOIN
2094 * USING and a merged column has an equivalence MERGEDVAR = CONSTANT.
2095 * By the time it gets here, the merged column will look like
2096 * COALESCE(LEFTVAR, RIGHTVAR)
2097 * and we will have a full-join clause LEFTVAR = RIGHTVAR that we can match
2098 * the COALESCE expression to. In this situation we can push LEFTVAR = CONSTANT
2099 * and RIGHTVAR = CONSTANT into the input relations, since any rows not
2100 * meeting these conditions cannot contribute to the join result.
2101 *
2102 * Again, there isn't any traction to be gained by trying to deal with
2103 * clauses comparing a mergedvar to a non-pseudoconstant. So we can make
2104 * use of the EquivalenceClasses to search for matching variables that were
2105 * equivalenced to constants. The interesting outer-join clauses were
2106 * accumulated for us by distribute_qual_to_rels.
2107 *
2108 * When we find one of these cases, we implement the changes we want by
2109 * generating a new equivalence clause INNERVAR = CONSTANT (or LEFTVAR, etc)
2110 * and pushing it into the EquivalenceClass structures. This is because we
2111 * may already know that INNERVAR is equivalenced to some other var(s), and
2112 * we'd like the constant to propagate to them too. Note that it would be
2113 * unsafe to merge any existing EC for INNERVAR with the OUTERVAR's EC ---
2114 * that could result in propagating constant restrictions from
2115 * INNERVAR to OUTERVAR, which would be very wrong.
2116 *
2117 * It's possible that the INNERVAR is also an OUTERVAR for some other
2118 * outer-join clause, in which case the process can be repeated. So we repeat
2119 * looping over the lists of clauses until no further deductions can be made.
2120 * Whenever we do make a deduction, we remove the generating clause from the
2121 * lists, since we don't want to make the same deduction twice.
2122 *
2123 * If we don't find any match for a set-aside outer join clause, we must
2124 * throw it back into the regular joinclause processing by passing it to
2125 * distribute_restrictinfo_to_rels(). If we do generate a derived clause,
2126 * however, the outer-join clause is redundant. We must still put some
2127 * clause into the regular processing, because otherwise the join will be
2128 * seen as a clauseless join and avoided during join order searching.
2129 * We handle this by generating a constant-TRUE clause that is marked with
2130 * the same required_relids etc as the removed outer-join clause, thus
2131 * making it a join clause between the correct relations.
2132 */
2133void
2134reconsider_outer_join_clauses(PlannerInfo *root)
2135{
2136 bool found;
2137 ListCell *cell;
2138
2139 /* Outer loop repeats until we find no more deductions */
2140 do
2141 {
2142 found = false;
2143
2144 /* Process the LEFT JOIN clauses */
2145 foreach(cell, root->left_join_clauses)
2146 {
2147 OuterJoinClauseInfo *ojcinfo = (OuterJoinClauseInfo *) lfirst(cell);
2148
2149 if (reconsider_outer_join_clause(root, ojcinfo, true))
2150 {
2151 RestrictInfo *rinfo = ojcinfo->rinfo;
2152
2153 found = true;
2154 /* remove it from the list */
2155 root->left_join_clauses =
2156 foreach_delete_current(root->left_join_clauses, cell);
2157 /* throw back a dummy replacement clause (see notes above) */
2158 rinfo = make_restrictinfo(root,
2159 (Expr *) makeBoolConst(true, false),
2160 rinfo->is_pushed_down,
2161 rinfo->has_clone,
2162 rinfo->is_clone,
2163 false, /* pseudoconstant */
2164 0, /* security_level */
2165 rinfo->required_relids,
2166 rinfo->incompatible_relids,
2167 rinfo->outer_relids);
2168 distribute_restrictinfo_to_rels(root, rinfo);
2169 }
2170 }
2171
2172 /* Process the RIGHT JOIN clauses */
2173 foreach(cell, root->right_join_clauses)
2174 {
2175 OuterJoinClauseInfo *ojcinfo = (OuterJoinClauseInfo *) lfirst(cell);
2176
2177 if (reconsider_outer_join_clause(root, ojcinfo, false))
2178 {
2179 RestrictInfo *rinfo = ojcinfo->rinfo;
2180
2181 found = true;
2182 /* remove it from the list */
2183 root->right_join_clauses =
2184 foreach_delete_current(root->right_join_clauses, cell);
2185 /* throw back a dummy replacement clause (see notes above) */
2186 rinfo = make_restrictinfo(root,
2187 (Expr *) makeBoolConst(true, false),
2188 rinfo->is_pushed_down,
2189 rinfo->has_clone,
2190 rinfo->is_clone,
2191 false, /* pseudoconstant */
2192 0, /* security_level */
2193 rinfo->required_relids,
2194 rinfo->incompatible_relids,
2195 rinfo->outer_relids);
2196 distribute_restrictinfo_to_rels(root, rinfo);
2197 }
2198 }
2199
2200 /* Process the FULL JOIN clauses */
2201 foreach(cell, root->full_join_clauses)
2202 {
2203 OuterJoinClauseInfo *ojcinfo = (OuterJoinClauseInfo *) lfirst(cell);
2204
2205 if (reconsider_full_join_clause(root, ojcinfo))
2206 {
2207 RestrictInfo *rinfo = ojcinfo->rinfo;
2208
2209 found = true;
2210 /* remove it from the list */
2211 root->full_join_clauses =
2212 foreach_delete_current(root->full_join_clauses, cell);
2213 /* throw back a dummy replacement clause (see notes above) */
2214 rinfo = make_restrictinfo(root,
2215 (Expr *) makeBoolConst(true, false),
2216 rinfo->is_pushed_down,
2217 rinfo->has_clone,
2218 rinfo->is_clone,
2219 false, /* pseudoconstant */
2220 0, /* security_level */
2221 rinfo->required_relids,
2222 rinfo->incompatible_relids,
2223 rinfo->outer_relids);
2224 distribute_restrictinfo_to_rels(root, rinfo);
2225 }
2226 }
2227 } while (found);
2228
2229 /* Now, any remaining clauses have to be thrown back */
2230 foreach(cell, root->left_join_clauses)
2231 {
2232 OuterJoinClauseInfo *ojcinfo = (OuterJoinClauseInfo *) lfirst(cell);
2233
2234 distribute_restrictinfo_to_rels(root, ojcinfo->rinfo);
2235 }
2236 foreach(cell, root->right_join_clauses)
2237 {
2238 OuterJoinClauseInfo *ojcinfo = (OuterJoinClauseInfo *) lfirst(cell);
2239
2240 distribute_restrictinfo_to_rels(root, ojcinfo->rinfo);
2241 }
2242 foreach(cell, root->full_join_clauses)
2243 {
2244 OuterJoinClauseInfo *ojcinfo = (OuterJoinClauseInfo *) lfirst(cell);
2245
2246 distribute_restrictinfo_to_rels(root, ojcinfo->rinfo);
2247 }
2248}
2249
2250/*
2251 * reconsider_outer_join_clauses for a single LEFT/RIGHT JOIN clause
2252 *
2253 * Returns true if we were able to propagate a constant through the clause.
2254 */
2255static bool
2256reconsider_outer_join_clause(PlannerInfo *root, OuterJoinClauseInfo *ojcinfo,
2257 bool outer_on_left)
2258{
2259 RestrictInfo *rinfo = ojcinfo->rinfo;
2260 SpecialJoinInfo *sjinfo = ojcinfo->sjinfo;
2261 Expr *outervar,
2262 *innervar;
2263 Oid opno,
2264 collation,
2265 left_type,
2266 right_type,
2267 inner_datatype;
2268 Relids inner_relids;
2269 ListCell *lc1;
2270
2271 Assert(is_opclause(rinfo->clause));
2272 opno = ((OpExpr *) rinfo->clause)->opno;
2273 collation = ((OpExpr *) rinfo->clause)->inputcollid;
2274
2275 /* Extract needed info from the clause */
2276 op_input_types(opno, &left_type, &right_type);
2277 if (outer_on_left)
2278 {
2279 outervar = (Expr *) get_leftop(rinfo->clause);
2280 innervar = (Expr *) get_rightop(rinfo->clause);
2281 inner_datatype = right_type;
2282 inner_relids = rinfo->right_relids;
2283 }
2284 else
2285 {
2286 outervar = (Expr *) get_rightop(rinfo->clause);
2287 innervar = (Expr *) get_leftop(rinfo->clause);
2288 inner_datatype = left_type;
2289 inner_relids = rinfo->left_relids;
2290 }
2291
2292 /* Scan EquivalenceClasses for a match to outervar */
2293 foreach(lc1, root->eq_classes)
2294 {
2295 EquivalenceClass *cur_ec = (EquivalenceClass *) lfirst(lc1);
2296 bool match;
2297 ListCell *lc2;
2298
2299 /* We don't expect any children yet */
2300 Assert(cur_ec->ec_childmembers == NULL);
2301
2302 /* Ignore EC unless it contains pseudoconstants */
2303 if (!cur_ec->ec_has_const)
2304 continue;
2305 /* Never match to a volatile EC */
2306 if (cur_ec->ec_has_volatile)
2307 continue;
2308 /* It has to match the outer-join clause as to semantics, too */
2309 if (collation != cur_ec->ec_collation)
2310 continue;
2311 if (!equal(rinfo->mergeopfamilies, cur_ec->ec_opfamilies))
2312 continue;
2313 /* Does it contain a match to outervar? */
2314 match = false;
2315 foreach(lc2, cur_ec->ec_members)
2316 {
2317 EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc2);
2318
2319 /* Child members should not exist in ec_members */
2320 Assert(!cur_em->em_is_child);
2321 if (equal(outervar, cur_em->em_expr))
2322 {
2323 match = true;
2324 break;
2325 }
2326 }
2327 if (!match)
2328 continue; /* no match, so ignore this EC */
2329
2330 /*
2331 * Yes it does! Try to generate a clause INNERVAR = CONSTANT for each
2332 * CONSTANT in the EC. Note that we must succeed with at least one
2333 * constant before we can decide to throw away the outer-join clause.
2334 */
2335 match = false;
2336 foreach(lc2, cur_ec->ec_members)
2337 {
2338 EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc2);
2339 Oid eq_op;
2340 RestrictInfo *newrinfo;
2341 JoinDomain *jdomain;
2342
2343 if (!cur_em->em_is_const)
2344 continue; /* ignore non-const members */
2345 eq_op = select_equality_operator(cur_ec,
2346 inner_datatype,
2347 cur_em->em_datatype);
2348 if (!OidIsValid(eq_op))
2349 continue; /* can't generate equality */
2350 newrinfo = build_implied_join_equality(root,
2351 eq_op,
2352 cur_ec->ec_collation,
2353 innervar,
2354 cur_em->em_expr,
2355 bms_copy(inner_relids),
2356 cur_ec->ec_min_security);
2357 /* This equality holds within the OJ's child JoinDomain */
2358 jdomain = find_join_domain(root, sjinfo->syn_righthand);
2359 if (process_equivalence(root, &newrinfo, jdomain))
2360 match = true;
2361 }
2362
2363 /*
2364 * If we were able to equate INNERVAR to any constant, report success.
2365 * Otherwise, fall out of the search loop, since we know the OUTERVAR
2366 * appears in at most one EC.
2367 */
2368 if (match)
2369 return true;
2370 else
2371 break;
2372 }
2373
2374 return false; /* failed to make any deduction */
2375}
2376
2377/*
2378 * reconsider_outer_join_clauses for a single FULL JOIN clause
2379 *
2380 * Returns true if we were able to propagate a constant through the clause.
2381 */
2382static bool
2383reconsider_full_join_clause(PlannerInfo *root, OuterJoinClauseInfo *ojcinfo)
2384{
2385 RestrictInfo *rinfo = ojcinfo->rinfo;
2386 SpecialJoinInfo *sjinfo = ojcinfo->sjinfo;
2387 Relids fjrelids = bms_make_singleton(sjinfo->ojrelid);
2388 Expr *leftvar;
2389 Expr *rightvar;
2390 Oid opno,
2391 collation,
2392 left_type,
2393 right_type;
2394 Relids left_relids,
2395 right_relids;
2396 ListCell *lc1;
2397
2398 /* Extract needed info from the clause */
2399 Assert(is_opclause(rinfo->clause));
2400 opno = ((OpExpr *) rinfo->clause)->opno;
2401 collation = ((OpExpr *) rinfo->clause)->inputcollid;
2402 op_input_types(opno, &left_type, &right_type);
2403 leftvar = (Expr *) get_leftop(rinfo->clause);
2404 rightvar = (Expr *) get_rightop(rinfo->clause);
2405 left_relids = rinfo->left_relids;
2406 right_relids = rinfo->right_relids;
2407
2408 foreach(lc1, root->eq_classes)
2409 {
2410 EquivalenceClass *cur_ec = (EquivalenceClass *) lfirst(lc1);
2411 EquivalenceMember *coal_em = NULL;
2412 bool match;
2413 bool matchleft;
2414 bool matchright;
2415 ListCell *lc2;
2416 int coal_idx = -1;
2417
2418 /* We don't expect any children yet */
2419 Assert(cur_ec->ec_childmembers == NULL);
2420
2421 /* Ignore EC unless it contains pseudoconstants */
2422 if (!cur_ec->ec_has_const)
2423 continue;
2424 /* Never match to a volatile EC */
2425 if (cur_ec->ec_has_volatile)
2426 continue;
2427 /* It has to match the outer-join clause as to semantics, too */
2428 if (collation != cur_ec->ec_collation)
2429 continue;
2430 if (!equal(rinfo->mergeopfamilies, cur_ec->ec_opfamilies))
2431 continue;
2432
2433 /*
2434 * Does it contain a COALESCE(leftvar, rightvar) construct?
2435 *
2436 * We can assume the COALESCE() inputs are in the same order as the
2437 * join clause, since both were automatically generated in the cases
2438 * we care about.
2439 *
2440 * XXX currently this may fail to match in cross-type cases because
2441 * the COALESCE will contain typecast operations while the join clause
2442 * may not (if there is a cross-type mergejoin operator available for
2443 * the two column types). Is it OK to strip implicit coercions from
2444 * the COALESCE arguments?
2445 */
2446 match = false;
2447 foreach(lc2, cur_ec->ec_members)
2448 {
2449 coal_em = (EquivalenceMember *) lfirst(lc2);
2450
2451 /* Child members should not exist in ec_members */
2452 Assert(!coal_em->em_is_child);
2453 if (IsA(coal_em->em_expr, CoalesceExpr))
2454 {
2455 CoalesceExpr *cexpr = (CoalesceExpr *) coal_em->em_expr;
2456 Node *cfirst;
2457 Node *csecond;
2458
2459 if (list_length(cexpr->args) != 2)
2460 continue;
2461 cfirst = (Node *) linitial(cexpr->args);
2462 csecond = (Node *) lsecond(cexpr->args);
2463
2464 /*
2465 * The COALESCE arguments will be marked as possibly nulled by
2466 * the full join, while we wish to generate clauses that apply
2467 * to the join's inputs. So we must strip the join from the
2468 * nullingrels fields of cfirst/csecond before comparing them
2469 * to leftvar/rightvar. (Perhaps with a less hokey
2470 * representation for FULL JOIN USING output columns, this
2471 * wouldn't be needed?)
2472 */
2473 cfirst = remove_nulling_relids(cfirst, fjrelids, NULL);
2474 csecond = remove_nulling_relids(csecond, fjrelids, NULL);
2475
2476 if (equal(leftvar, cfirst) && equal(rightvar, csecond))
2477 {
2478 coal_idx = foreach_current_index(lc2);
2479 match = true;
2480 break;
2481 }
2482 }
2483 }
2484 if (!match)
2485 continue; /* no match, so ignore this EC */
2486
2487 /*
2488 * Yes it does! Try to generate clauses LEFTVAR = CONSTANT and
2489 * RIGHTVAR = CONSTANT for each CONSTANT in the EC. Note that we must
2490 * succeed with at least one constant for each var before we can
2491 * decide to throw away the outer-join clause.
2492 */
2493 matchleft = matchright = false;
2494 foreach(lc2, cur_ec->ec_members)
2495 {
2496 EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc2);
2497 Oid eq_op;
2498 RestrictInfo *newrinfo;
2499 JoinDomain *jdomain;
2500
2501 if (!cur_em->em_is_const)
2502 continue; /* ignore non-const members */
2503 eq_op = select_equality_operator(cur_ec,
2504 left_type,
2505 cur_em->em_datatype);
2506 if (OidIsValid(eq_op))
2507 {
2508 newrinfo = build_implied_join_equality(root,
2509 eq_op,
2510 cur_ec->ec_collation,
2511 leftvar,
2512 cur_em->em_expr,
2513 bms_copy(left_relids),
2514 cur_ec->ec_min_security);
2515 /* This equality holds within the lefthand child JoinDomain */
2516 jdomain = find_join_domain(root, sjinfo->syn_lefthand);
2517 if (process_equivalence(root, &newrinfo, jdomain))
2518 matchleft = true;
2519 }
2520 eq_op = select_equality_operator(cur_ec,
2521 right_type,
2522 cur_em->em_datatype);
2523 if (OidIsValid(eq_op))
2524 {
2525 newrinfo = build_implied_join_equality(root,
2526 eq_op,
2527 cur_ec->ec_collation,
2528 rightvar,
2529 cur_em->em_expr,
2530 bms_copy(right_relids),
2531 cur_ec->ec_min_security);
2532 /* This equality holds within the righthand child JoinDomain */
2533 jdomain = find_join_domain(root, sjinfo->syn_righthand);
2534 if (process_equivalence(root, &newrinfo, jdomain))
2535 matchright = true;
2536 }
2537 }
2538
2539 /*
2540 * If we were able to equate both vars to constants, we're done, and
2541 * we can throw away the full-join clause as redundant. Moreover, we
2542 * can remove the COALESCE entry from the EC, since the added
2543 * restrictions ensure it will always have the expected value. (We
2544 * don't bother trying to update ec_relids or ec_sources.)
2545 */
2546 if (matchleft && matchright)
2547 {
2548 cur_ec->ec_members = list_delete_nth_cell(cur_ec->ec_members, coal_idx);
2549 return true;
2550 }
2551
2552 /*
2553 * Otherwise, fall out of the search loop, since we know the COALESCE
2554 * appears in at most one EC (XXX might stop being true if we allow
2555 * stripping of coercions above?)
2556 */
2557 break;
2558 }
2559
2560 return false; /* failed to make any deduction */
2561}
2562
2563/*
2564 * rebuild_eclass_attr_needed
2565 * Put back attr_needed bits for Vars/PHVs needed for join eclasses.
2566 *
2567 * This is used to rebuild attr_needed/ph_needed sets after removal of a
2568 * useless outer join. It should match what
2569 * generate_base_implied_equalities_no_const did, except that we call
2570 * add_vars_to_attr_needed not add_vars_to_targetlist.
2571 */
2572void
2573rebuild_eclass_attr_needed(PlannerInfo *root)
2574{
2575 ListCell *lc;
2576
2577 foreach(lc, root->eq_classes)
2578 {
2579 EquivalenceClass *ec = (EquivalenceClass *) lfirst(lc);
2580
2581 /*
2582 * We don't expect any EC child members to exist at this point. Ensure
2583 * that's the case, otherwise, we might be getting asked to do
2584 * something this function hasn't been coded for.
2585 */
2586 Assert(ec->ec_childmembers == NULL);
2587
2588 /* Need do anything only for a multi-member, no-const EC. */
2589 if (list_length(ec->ec_members) > 1 && !ec->ec_has_const)
2590 {
2591 ListCell *lc2;
2592
2593 foreach(lc2, ec->ec_members)
2594 {
2595 EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc2);
2596 List *vars = pull_var_clause((Node *) cur_em->em_expr,
2597 PVC_RECURSE_AGGREGATES |
2598 PVC_RECURSE_WINDOWFUNCS |
2599 PVC_INCLUDE_PLACEHOLDERS);
2600
2601 add_vars_to_attr_needed(root, vars, ec->ec_relids);
2602 list_free(vars);
2603 }
2604 }
2605 }
2606}
2607
2608/*
2609 * find_join_domain
2610 * Find the highest JoinDomain enclosed within the given relid set.
2611 *
2612 * (We could avoid this search at the cost of complicating APIs elsewhere,
2613 * which doesn't seem worth it.)
2614 */
2615static JoinDomain *
2616find_join_domain(PlannerInfo *root, Relids relids)
2617{
2618 ListCell *lc;
2619
2620 foreach(lc, root->join_domains)
2621 {
2622 JoinDomain *jdomain = (JoinDomain *) lfirst(lc);
2623
2624 if (bms_is_subset(jdomain->jd_relids, relids))
2625 return jdomain;
2626 }
2627 elog(ERROR, "failed to find appropriate JoinDomain");
2628 return NULL; /* keep compiler quiet */
2629}
2630
2631
2632/*
2633 * exprs_known_equal
2634 * Detect whether two expressions are known equal due to equivalence
2635 * relationships.
2636 *
2637 * If opfamily is given, the expressions must be known equal per the semantics
2638 * of that opfamily (note it has to be a btree opfamily, since those are the
2639 * only opfamilies equivclass.c deals with). If opfamily is InvalidOid, we'll
2640 * return true if they're equal according to any opfamily, which is fuzzy but
2641 * OK for estimation purposes.
2642 *
2643 * Note: does not bother to check for "equal(item1, item2)"; caller must
2644 * check that case if it's possible to pass identical items.
2645 */
2646bool
2647exprs_known_equal(PlannerInfo *root, Node *item1, Node *item2, Oid opfamily)
2648{
2649 ListCell *lc1;
2650
2651 foreach(lc1, root->eq_classes)
2652 {
2653 EquivalenceClass *ec = (EquivalenceClass *) lfirst(lc1);
2654 bool item1member = false;
2655 bool item2member = false;
2656 ListCell *lc2;
2657
2658 /* Never match to a volatile EC */
2659 if (ec->ec_has_volatile)
2660 continue;
2661
2662 /*
2663 * It's okay to consider ec_broken ECs here. Brokenness just means we
2664 * couldn't derive all the implied clauses we'd have liked to; it does
2665 * not invalidate our knowledge that the members are equal.
2666 */
2667
2668 /* Ignore if this EC doesn't use specified opfamily */
2669 if (OidIsValid(opfamily) &&
2670 !list_member_oid(ec->ec_opfamilies, opfamily))
2671 continue;
2672
2673 /* Ignore children here */
2674 foreach(lc2, ec->ec_members)
2675 {
2676 EquivalenceMember *em = (EquivalenceMember *) lfirst(lc2);
2677
2678 /* Child members should not exist in ec_members */
2679 Assert(!em->em_is_child);
2680 if (equal(item1, em->em_expr))
2681 item1member = true;
2682 else if (equal(item2, em->em_expr))
2683 item2member = true;
2684 /* Exit as soon as equality is proven */
2685 if (item1member && item2member)
2686 return true;
2687 }
2688 }
2689 return false;
2690}
2691
2692
2693/*
2694 * match_eclasses_to_foreign_key_col
2695 * See whether a foreign key column match is proven by any eclass.
2696 *
2697 * If the referenced and referencing Vars of the fkey's colno'th column are
2698 * known equal due to any eclass, return that eclass; otherwise return NULL.
2699 * (In principle there might be more than one matching eclass if multiple
2700 * collations are involved, but since collation doesn't matter for equality,
2701 * we ignore that fine point here.) This is much like exprs_known_equal,
2702 * except for the format of the input.
2703 *
2704 * On success, we also set fkinfo->eclass[colno] to the matching eclass,
2705 * and set fkinfo->fk_eclass_member[colno] to the eclass member for the
2706 * referencing Var.
2707 */
2708EquivalenceClass *
2709match_eclasses_to_foreign_key_col(PlannerInfo *root,
2710 ForeignKeyOptInfo *fkinfo,
2711 int colno)
2712{
2713 Index var1varno = fkinfo->con_relid;
2714 AttrNumber var1attno = fkinfo->conkey[colno];
2715 Index var2varno = fkinfo->ref_relid;
2716 AttrNumber var2attno = fkinfo->confkey[colno];
2717 Oid eqop = fkinfo->conpfeqop[colno];
2718 RelOptInfo *rel1 = root->simple_rel_array[var1varno];
2719 RelOptInfo *rel2 = root->simple_rel_array[var2varno];
2720 List *opfamilies = NIL; /* compute only if needed */
2721 Bitmapset *matching_ecs;
2722 int i;
2723
2724 /* Consider only eclasses mentioning both relations */
2725 Assert(root->ec_merging_done);
2726 Assert(IS_SIMPLE_REL(rel1));
2727 Assert(IS_SIMPLE_REL(rel2));
2728 matching_ecs = bms_intersect(rel1->eclass_indexes,
2729 rel2->eclass_indexes);
2730
2731 i = -1;
2732 while ((i = bms_next_member(matching_ecs, i)) >= 0)
2733 {
2734 EquivalenceClass *ec = (EquivalenceClass *) list_nth(root->eq_classes,
2735 i);
2736 EquivalenceMember *item1_em = NULL;
2737 EquivalenceMember *item2_em = NULL;
2738 ListCell *lc2;
2739
2740 /* Never match to a volatile EC */
2741 if (ec->ec_has_volatile)
2742 continue;
2743
2744 /*
2745 * It's okay to consider "broken" ECs here, see exprs_known_equal.
2746 * Ignore children here.
2747 */
2748 foreach(lc2, ec->ec_members)
2749 {
2750 EquivalenceMember *em = (EquivalenceMember *) lfirst(lc2);
2751 Var *var;
2752
2753 /* Child members should not exist in ec_members */
2754 Assert(!em->em_is_child);
2755
2756 /* EM must be a Var, possibly with RelabelType */
2757 var = (Var *) em->em_expr;
2758 while (var && IsA(var, RelabelType))
2759 var = (Var *) ((RelabelType *) var)->arg;
2760 if (!(var && IsA(var, Var)))
2761 continue;
2762
2763 /* Match? */
2764 if (var->varno == var1varno && var->varattno == var1attno)
2765 item1_em = em;
2766 else if (var->varno == var2varno && var->varattno == var2attno)
2767 item2_em = em;
2768
2769 /* Have we found both PK and FK column in this EC? */
2770 if (item1_em && item2_em)
2771 {
2772 /*
2773 * Succeed if eqop matches EC's opfamilies. We could test
2774 * this before scanning the members, but it's probably cheaper
2775 * to test for member matches first.
2776 */
2777 if (opfamilies == NIL) /* compute if we didn't already */
2778 opfamilies = get_mergejoin_opfamilies(eqop);
2779 if (equal(opfamilies, ec->ec_opfamilies))
2780 {
2781 fkinfo->eclass[colno] = ec;
2782 fkinfo->fk_eclass_member[colno] = item2_em;
2783 return ec;
2784 }
2785 /* Otherwise, done with this EC, move on to the next */
2786 break;
2787 }
2788 }
2789 }
2790 return NULL;
2791}
2792
2793/*
2794 * find_derived_clause_for_ec_member
2795 * Search for a previously-derived clause mentioning the given EM.
2796 *
2797 * The eclass should be an ec_has_const EC, of which the EM is a non-const
2798 * member. This should ensure there is just one derived clause mentioning
2799 * the EM (and equating it to a constant).
2800 * Returns NULL if no such clause can be found.
2801 */
2802RestrictInfo *
2812
2813
2814/*
2815 * add_child_rel_equivalences
2816 * Search for EC members that reference the root parent of child_rel, and
2817 * add transformed members referencing the child_rel.
2818 *
2819 * Note that this function won't be called at all unless we have at least some
2820 * reason to believe that the EC members it generates will be useful.
2821 *
2822 * parent_rel and child_rel could be derived from appinfo, but since the
2823 * caller has already computed them, we might as well just pass them in.
2824 *
2825 * The passed-in AppendRelInfo is not used when the parent_rel is not a
2826 * top-level baserel, since it shows the mapping from the parent_rel but
2827 * we need to translate EC expressions that refer to the top-level parent.
2828 * Using it is faster than using adjust_appendrel_attrs_multilevel(), though,
2829 * so we prefer it when we can.
2830 */
2831void
2832add_child_rel_equivalences(PlannerInfo *root,
2833 AppendRelInfo *appinfo,
2834 RelOptInfo *parent_rel,
2835 RelOptInfo *child_rel)
2836{
2837 Relids top_parent_relids = child_rel->top_parent_relids;
2838 Relids child_relids = child_rel->relids;
2839 int i;
2840
2841 /*
2842 * EC merging should be complete already, so we can use the parent rel's
2843 * eclass_indexes to avoid searching all of root->eq_classes.
2844 */
2845 Assert(root->ec_merging_done);
2846 Assert(IS_SIMPLE_REL(parent_rel));
2847
2848 i = -1;
2849 while ((i = bms_next_member(parent_rel->eclass_indexes, i)) >= 0)
2850 {
2851 EquivalenceClass *cur_ec = (EquivalenceClass *) list_nth(root->eq_classes, i);
2852
2853 /*
2854 * If this EC contains a volatile expression, then generating child
2855 * EMs would be downright dangerous, so skip it. We rely on a
2856 * volatile EC having only one EM.
2857 */
2858 if (cur_ec->ec_has_volatile)
2859 continue;
2860
2861 /* Sanity check eclass_indexes only contain ECs for parent_rel */
2862 Assert(bms_is_subset(top_parent_relids, cur_ec->ec_relids));
2863
2864 foreach_node(EquivalenceMember, cur_em, cur_ec->ec_members)
2865 {
2866 if (cur_em->em_is_const)
2867 continue; /* ignore consts here */
2868
2869 /* Child members should not exist in ec_members */
2870 Assert(!cur_em->em_is_child);
2871
2872 /*
2873 * Consider only members that reference and can be computed at
2874 * child's topmost parent rel. In particular we want to exclude
2875 * parent-rel Vars that have nonempty varnullingrels. Translating
2876 * those might fail, if the transformed expression wouldn't be a
2877 * simple Var; and in any case it wouldn't produce a member that
2878 * has any use in creating plans for the child rel.
2879 */
2880 if (bms_is_subset(cur_em->em_relids, top_parent_relids) &&
2881 !bms_is_empty(cur_em->em_relids))
2882 {
2883 /* OK, generate transformed child version */
2884 Expr *child_expr;
2885 Relids new_relids;
2886
2887 if (parent_rel->reloptkind == RELOPT_BASEREL)
2888 {
2889 /* Simple single-level transformation */
2890 child_expr = (Expr *)
2891 adjust_appendrel_attrs(root,
2892 (Node *) cur_em->em_expr,
2893 1, &appinfo);
2894 }
2895 else
2896 {
2897 /* Must do multi-level transformation */
2898 child_expr = (Expr *)
2899 adjust_appendrel_attrs_multilevel(root,
2900 (Node *) cur_em->em_expr,
2901 child_rel,
2902 child_rel->top_parent);
2903 }
2904
2905 /*
2906 * Transform em_relids to match. Note we do *not* do
2907 * pull_varnos(child_expr) here, as for example the
2908 * transformation might have substituted a constant, but we
2909 * don't want the child member to be marked as constant.
2910 */
2911 new_relids = bms_difference(cur_em->em_relids,
2912 top_parent_relids);
2913 new_relids = bms_add_members(new_relids, child_relids);
2914
2915 add_child_eq_member(root,
2916 cur_ec,
2917 i,
2918 child_expr,
2919 new_relids,
2920 cur_em->em_jdomain,
2921 cur_em,
2922 cur_em->em_datatype,
2923 child_rel->relid);
2924 }
2925 }
2926 }
2927}
2928
2929/*
2930 * add_child_join_rel_equivalences
2931 * Like add_child_rel_equivalences(), but for joinrels
2932 *
2933 * Here we find the ECs relevant to the top parent joinrel and add transformed
2934 * member expressions that refer to this child joinrel.
2935 *
2936 * Note that this function won't be called at all unless we have at least some
2937 * reason to believe that the EC members it generates will be useful.
2938 */
2939void
2940add_child_join_rel_equivalences(PlannerInfo *root,
2941 int nappinfos, AppendRelInfo **appinfos,
2942 RelOptInfo *parent_joinrel,
2943 RelOptInfo *child_joinrel)
2944{
2945 Relids top_parent_relids = child_joinrel->top_parent_relids;
2946 Relids child_relids = child_joinrel->relids;
2947 Bitmapset *matching_ecs;
2948 MemoryContext oldcontext;
2949 int i;
2950
2951 Assert(IS_JOIN_REL(child_joinrel) && IS_JOIN_REL(parent_joinrel));
2952
2953 /* We need consider only ECs that mention the parent joinrel */
2954 matching_ecs = get_eclass_indexes_for_relids(root, top_parent_relids);
2955
2956 /*
2957 * If we're being called during GEQO join planning, we still have to
2958 * create any new EC members in the main planner context, to avoid having
2959 * a corrupt EC data structure after the GEQO context is reset. This is
2960 * problematic since we'll leak memory across repeated GEQO cycles. For
2961 * now, though, bloat is better than crash. If it becomes a real issue
2962 * we'll have to do something to avoid generating duplicate EC members.
2963 */
2964 oldcontext = MemoryContextSwitchTo(root->planner_cxt);
2965
2966 i = -1;
2967 while ((i = bms_next_member(matching_ecs, i)) >= 0)
2968 {
2969 EquivalenceClass *cur_ec = (EquivalenceClass *) list_nth(root->eq_classes, i);
2970
2971 /*
2972 * If this EC contains a volatile expression, then generating child
2973 * EMs would be downright dangerous, so skip it. We rely on a
2974 * volatile EC having only one EM.
2975 */
2976 if (cur_ec->ec_has_volatile)
2977 continue;
2978
2979 /* Sanity check on get_eclass_indexes_for_relids result */
2980 Assert(bms_overlap(top_parent_relids, cur_ec->ec_relids));
2981
2982 foreach_node(EquivalenceMember, cur_em, cur_ec->ec_members)
2983 {
2984 if (cur_em->em_is_const)
2985 continue; /* ignore consts here */
2986
2987 /* Child members should not exist in ec_members */
2988 Assert(!cur_em->em_is_child);
2989
2990 /*
2991 * We may ignore expressions that reference a single baserel,
2992 * because add_child_rel_equivalences should have handled them.
2993 */
2994 if (bms_membership(cur_em->em_relids) != BMS_MULTIPLE)
2995 continue;
2996
2997 /* Does this member reference child's topmost parent rel? */
2998 if (bms_overlap(cur_em->em_relids, top_parent_relids))
2999 {
3000 /* Yes, generate transformed child version */
3001 Expr *child_expr;
3002 Relids new_relids;
3003
3004 if (parent_joinrel->reloptkind == RELOPT_JOINREL)
3005 {
3006 /* Simple single-level transformation */
3007 child_expr = (Expr *)
3008 adjust_appendrel_attrs(root,
3009 (Node *) cur_em->em_expr,
3010 nappinfos, appinfos);
3011 }
3012 else
3013 {
3014 /* Must do multi-level transformation */
3015 Assert(parent_joinrel->reloptkind == RELOPT_OTHER_JOINREL);
3016 child_expr = (Expr *)
3017 adjust_appendrel_attrs_multilevel(root,
3018 (Node *) cur_em->em_expr,
3019 child_joinrel,
3020 child_joinrel->top_parent);
3021 }
3022
3023 /*
3024 * Transform em_relids to match. Note we do *not* do
3025 * pull_varnos(child_expr) here, as for example the
3026 * transformation might have substituted a constant, but we
3027 * don't want the child member to be marked as constant.
3028 */
3029 new_relids = bms_difference(cur_em->em_relids,
3030 top_parent_relids);
3031 new_relids = bms_add_members(new_relids, child_relids);
3032
3033 /*
3034 * Add new child member to the EquivalenceClass. Because this
3035 * is a RELOPT_OTHER_JOINREL which has multiple component
3036 * relids, there is no ideal place to store these members in
3037 * the class. Ordinarily, child members are stored in the
3038 * ec_childmembers[] array element corresponding to their
3039 * relid, however, here we have multiple component relids, so
3040 * there's no single ec_childmembers[] array element to store
3041 * this member. So that we still correctly find this member
3042 * in loops iterating over an EquivalenceMemberIterator, we
3043 * opt to store the member in the ec_childmembers array in
3044 * only the first component relid slot of the array. This
3045 * allows the member to be found, providing callers of
3046 * setup_eclass_member_iterator() specify all the component
3047 * relids for the RELOPT_OTHER_JOINREL, which they do. If we
3048 * opted to store the member in each ec_childmembers[] element
3049 * for all the component relids, then that would just result
3050 * in eclass_member_iterator_next() finding the member
3051 * multiple times, which is a waste of effort.
3052 */
3053 add_child_eq_member(root,
3054 cur_ec,
3055 -1,
3056 child_expr,
3057 new_relids,
3058 cur_em->em_jdomain,
3059 cur_em,
3060 cur_em->em_datatype,
3061 bms_next_member(child_joinrel->relids, -1));
3062 }
3063 }
3064 }
3065
3066 MemoryContextSwitchTo(oldcontext);
3067}
3068
3069/*
3070 * add_setop_child_rel_equivalences
3071 * Add equivalence members for each non-resjunk target in 'child_tlist'
3072 * to the EquivalenceClass in the corresponding setop_pathkey's pk_eclass.
3073 *
3074 * 'root' is the PlannerInfo belonging to the top-level set operation.
3075 * 'child_rel' is the RelOptInfo of the child relation we're adding
3076 * EquivalenceMembers for.
3077 * 'child_tlist' is the target list for the setop child relation. The target
3078 * list expressions are what we add as EquivalenceMembers.
3079 * 'setop_pathkeys' is a list of PathKeys which must contain an entry for each
3080 * non-resjunk target in 'child_tlist'.
3081 */
3082void
3083add_setop_child_rel_equivalences(PlannerInfo *root, RelOptInfo *child_rel,
3084 List *child_tlist, List *setop_pathkeys)
3085{
3086 ListCell *lc;
3087 ListCell *lc2 = list_head(setop_pathkeys);
3088
3089 foreach(lc, child_tlist)
3090 {
3091 TargetEntry *tle = lfirst_node(TargetEntry, lc);
3092 EquivalenceMember *parent_em;
3093 PathKey *pk;
3094
3095 if (tle->resjunk)
3096 continue;
3097
3098 if (lc2 == NULL)
3099 elog(ERROR, "too few pathkeys for set operation");
3100
3101 pk = lfirst_node(PathKey, lc2);
3102 parent_em = linitial(pk->pk_eclass->ec_members);
3103
3104 /*
3105 * We can safely pass the parent member as the first member in the
3106 * ec_members list as this is added first in generate_union_paths,
3107 * likewise, the JoinDomain can be that of the initial member of the
3108 * Pathkey's EquivalenceClass. We pass -1 for ec_index since we
3109 * maintain the eclass_indexes for the child_rel after the loop.
3110 */
3111 add_child_eq_member(root,
3112 pk->pk_eclass,
3113 -1,
3114 tle->expr,
3115 child_rel->relids,
3116 parent_em->em_jdomain,
3117 parent_em,
3118 exprType((Node *) tle->expr),
3119 child_rel->relid);
3120
3121 lc2 = lnext(setop_pathkeys, lc2);
3122 }
3123
3124 /*
3125 * transformSetOperationStmt() ensures that the targetlist never contains
3126 * any resjunk columns, so all eclasses that exist in 'root' must have
3127 * received a new member in the loop above. Add them to the child_rel's
3128 * eclass_indexes.
3129 */
3130 child_rel->eclass_indexes = bms_add_range(child_rel->eclass_indexes, 0,
3131 list_length(root->eq_classes) - 1);
3132}
3133
3134/*
3135 * setup_eclass_member_iterator
3136 * Setup an EquivalenceMemberIterator 'it' to iterate over all parent
3137 * EquivalenceMembers and child members belonging to the given 'ec'.
3138 *
3139 * This iterator returns:
3140 * - All parent members stored directly in ec_members for 'ec', and;
3141 * - Any child member added to the given ec by add_child_eq_member() where
3142 * the child_relid specified in the add_child_eq_member() call is a member
3143 * of the 'child_relids' parameter.
3144 *
3145 * Note:
3146 * The given 'child_relids' must remain allocated and not be changed for the
3147 * lifetime of the iterator.
3148 *
3149 * Parameters:
3150 * 'it' is a pointer to the iterator to set up. Normally stack allocated.
3151 * 'ec' is the EquivalenceClass from which to iterate members for.
3152 * 'child_relids' is the relids to return child members for.
3153 */
3154void
3155setup_eclass_member_iterator(EquivalenceMemberIterator *it,
3156 EquivalenceClass *ec, Relids child_relids)
3157{
3158 it->ec = ec;
3159 /* no need to set this if the class has no child members array set */
3160 it->child_relids = ec->ec_childmembers != NULL ? child_relids : NULL;
3161 it->current_relid = -1;
3162 it->current_list = ec->ec_members;
3163 it->current_cell = list_head(it->current_list);
3164}
3165
3166/*
3167 * eclass_member_iterator_next
3168 * Get the next EquivalenceMember from the EquivalenceMemberIterator 'it',
3169 * as setup by setup_eclass_member_iterator(). NULL is returned if there
3170 * are no members left, after which callers must not call
3171 * eclass_member_iterator_next() again for the given iterator.
3172 */
3173EquivalenceMember *
3174eclass_member_iterator_next(EquivalenceMemberIterator *it)
3175{
3176 while (it->current_list != NULL)
3177 {
3178 while (it->current_cell != NULL)
3179 {
3180 EquivalenceMember *em;
3181
3182 nextcell:
3183 em = lfirst_node(EquivalenceMember, it->current_cell);
3184 it->current_cell = lnext(it->current_list, it->current_cell);
3185 return em;
3186 }
3187
3188 /* Search for the next list to return members from */
3189 while ((it->current_relid = bms_next_member(it->child_relids, it->current_relid)) > 0)
3190 {
3191 /*
3192 * Be paranoid in case we're given relids above what we've sized
3193 * the ec_childmembers array to.
3194 */
3195 if (it->current_relid >= it->ec->ec_childmembers_size)
3196 return NULL;
3197
3198 it->current_list = it->ec->ec_childmembers[it->current_relid];
3199
3200 /* If there are members in this list, use it. */
3201 if (it->current_list != NIL)
3202 {
3203 /* point current_cell to the head of this list */
3204 it->current_cell = list_head(it->current_list);
3205 goto nextcell;
3206 }
3207 }
3208 return NULL;
3209 }
3210
3211 return NULL;
3212}
3213
3214/*
3215 * generate_implied_equalities_for_column
3216 * Create EC-derived joinclauses usable with a specific column.
3217 *
3218 * This is used by indxpath.c to extract potentially indexable joinclauses
3219 * from ECs, and can be used by foreign data wrappers for similar purposes.
3220 * We assume that only expressions in Vars of a single table are of interest,
3221 * but the caller provides a callback function to identify exactly which
3222 * such expressions it would like to know about.
3223 *
3224 * We assume that any given table/index column could appear in only one EC.
3225 * (This should be true in all but the most pathological cases, and if it
3226 * isn't, we stop on the first match anyway.) Therefore, what we return
3227 * is a redundant list of clauses equating the table/index column to each of
3228 * the other-relation values it is known to be equal to. Any one of
3229 * these clauses can be used to create a parameterized path, and there
3230 * is no value in using more than one. (But it *is* worthwhile to create
3231 * a separate parameterized path for each one, since that leads to different
3232 * join orders.)
3233 *
3234 * The caller can pass a Relids set of rels we aren't interested in joining
3235 * to, so as to save the work of creating useless clauses.
3236 */
3237List *
3238generate_implied_equalities_for_column(PlannerInfo *root,
3239 RelOptInfo *rel,
3240 ec_matches_callback_type callback,
3241 void *callback_arg,
3242 Relids prohibited_rels)
3243{
3244 List *result = NIL;
3245 bool is_child_rel = (rel->reloptkind == RELOPT_OTHER_MEMBER_REL);
3246 Relids parent_relids;
3247 int i;
3248
3249 /* Should be OK to rely on eclass_indexes */
3250 Assert(root->ec_merging_done);
3251
3252 /* Indexes are available only on base or "other" member relations. */
3253 Assert(IS_SIMPLE_REL(rel));
3254
3255 /* If it's a child rel, we'll need to know what its parent(s) are */
3256 if (is_child_rel)
3257 parent_relids = find_childrel_parents(root, rel);
3258 else
3259 parent_relids = NULL; /* not used, but keep compiler quiet */
3260
3261 i = -1;
3262 while ((i = bms_next_member(rel->eclass_indexes, i)) >= 0)
3263 {
3264 EquivalenceClass *cur_ec = (EquivalenceClass *) list_nth(root->eq_classes, i);
3265 EquivalenceMemberIterator it;
3266 EquivalenceMember *cur_em;
3267 ListCell *lc2;
3268
3269 /* Sanity check eclass_indexes only contain ECs for rel */
3270 Assert(is_child_rel || bms_is_subset(rel->relids, cur_ec->ec_relids));
3271
3272 /*
3273 * Won't generate joinclauses if const or single-member (the latter
3274 * test covers the volatile case too)
3275 */
3276 if (cur_ec->ec_has_const || list_length(cur_ec->ec_members) <= 1)
3277 continue;
3278
3279 /*
3280 * Scan members, looking for a match to the target column. Note that
3281 * child EC members are considered, but only when they belong to the
3282 * target relation. (Unlike regular members, the same expression
3283 * could be a child member of more than one EC. Therefore, it's
3284 * potentially order-dependent which EC a child relation's target
3285 * column gets matched to. This is annoying but it only happens in
3286 * corner cases, so for now we live with just reporting the first
3287 * match. See also get_eclass_for_sort_expr.)
3288 */
3289 setup_eclass_member_iterator(&it, cur_ec, rel->relids);
3290 while ((cur_em = eclass_member_iterator_next(&it)) != NULL)
3291 {
3292 if (bms_equal(cur_em->em_relids, rel->relids) &&
3293 callback(root, rel, cur_ec, cur_em, callback_arg))
3294 break;
3295 }
3296
3297 if (!cur_em)
3298 continue;
3299
3300 /*
3301 * Found our match. Scan the other EC members and attempt to generate
3302 * joinclauses. Ignore children here.
3303 */
3304 foreach(lc2, cur_ec->ec_members)
3305 {
3306 EquivalenceMember *other_em = (EquivalenceMember *) lfirst(lc2);
3307 Oid eq_op;
3308 RestrictInfo *rinfo;
3309
3310 /* Child members should not exist in ec_members */
3311 Assert(!other_em->em_is_child);
3312
3313 /* Make sure it'll be a join to a different rel */
3314 if (other_em == cur_em ||
3315 bms_overlap(other_em->em_relids, rel->relids))
3316 continue;
3317
3318 /* Forget it if caller doesn't want joins to this rel */
3319 if (bms_overlap(other_em->em_relids, prohibited_rels))
3320 continue;
3321
3322 /*
3323 * Also, if this is a child rel, avoid generating a useless join
3324 * to its parent rel(s).
3325 */
3326 if (is_child_rel &&
3327 bms_overlap(parent_relids, other_em->em_relids))
3328 continue;
3329
3330 eq_op = select_equality_operator(cur_ec,
3331 cur_em->em_datatype,
3332 other_em->em_datatype);
3333 if (!OidIsValid(eq_op))
3334 continue;
3335
3336 /* set parent_ec to mark as redundant with other joinclauses */
3337 rinfo = create_join_clause(root, cur_ec, eq_op,
3338 cur_em, other_em,
3339 cur_ec);
3340
3341 result = lappend(result, rinfo);
3342 }
3343
3344 /*
3345 * If somehow we failed to create any join clauses, we might as well
3346 * keep scanning the ECs for another match. But if we did make any,
3347 * we're done, because we don't want to return non-redundant clauses.
3348 */
3349 if (result)
3350 break;
3351 }
3352
3353 return result;
3354}
3355
3356/*
3357 * have_relevant_eclass_joinclause
3358 * Detect whether there is an EquivalenceClass that could produce
3359 * a joinclause involving the two given relations.
3360 *
3361 * This is essentially a very cut-down version of
3362 * generate_join_implied_equalities(). Note it's OK to occasionally say "yes"
3363 * incorrectly. Hence we don't bother with details like whether the lack of a
3364 * cross-type operator might prevent the clause from actually being generated.
3365 * False negatives are not always fatal either: they will discourage, but not
3366 * completely prevent, investigation of particular join pathways.
3367 */
3368bool
3369have_relevant_eclass_joinclause(PlannerInfo *root,
3370 RelOptInfo *rel1, RelOptInfo *rel2)
3371{
3372 Bitmapset *matching_ecs;
3373 int i;
3374
3375 /*
3376 * Examine only eclasses mentioning both rel1 and rel2.
3377 *
3378 * Note that we do not consider the possibility of an eclass generating
3379 * "join" clauses that mention just one of the rels plus an outer join
3380 * that could be formed from them. Although such clauses must be
3381 * correctly enforced when we form the outer join, they don't seem like
3382 * sufficient reason to prioritize this join over other ones. The join
3383 * ordering rules will force the join to be made when necessary.
3384 */
3385 matching_ecs = get_common_eclass_indexes(root, rel1->relids,
3386 rel2->relids);
3387
3388 i = -1;
3389 while ((i = bms_next_member(matching_ecs, i)) >= 0)
3390 {
3391 EquivalenceClass *ec = (EquivalenceClass *) list_nth(root->eq_classes,
3392 i);
3393
3394 /*
3395 * Sanity check that get_common_eclass_indexes gave only ECs
3396 * containing both rels.
3397 */
3398 Assert(bms_overlap(rel1->relids, ec->ec_relids));
3399 Assert(bms_overlap(rel2->relids, ec->ec_relids));
3400
3401 /*
3402 * Won't generate joinclauses if single-member (this test covers the
3403 * volatile case too)
3404 */
3405 if (list_length(ec->ec_members) <= 1)
3406 continue;
3407
3408 /*
3409 * We do not need to examine the individual members of the EC, because
3410 * all that we care about is whether each rel overlaps the relids of
3411 * at least one member, and get_common_eclass_indexes() and the single
3412 * member check above are sufficient to prove that. (As with
3413 * have_relevant_joinclause(), it is not necessary that the EC be able
3414 * to form a joinclause relating exactly the two given rels, only that
3415 * it be able to form a joinclause mentioning both, and this will
3416 * surely be true if both of them overlap ec_relids.)
3417 *
3418 * Note we don't test ec_broken; if we did, we'd need a separate code
3419 * path to look through ec_sources. Checking the membership anyway is
3420 * OK as a possibly-overoptimistic heuristic.
3421 *
3422 * We don't test ec_has_const either, even though a const eclass won't
3423 * generate real join clauses. This is because if we had "WHERE a.x =
3424 * b.y and a.x = 42", it is worth considering a join between a and b,
3425 * since the join result is likely to be small even though it'll end
3426 * up being an unqualified nestloop.
3427 */
3428
3429 return true;
3430 }
3431
3432 return false;
3433}
3434
3435
3436/*
3437 * has_relevant_eclass_joinclause
3438 * Detect whether there is an EquivalenceClass that could produce
3439 * a joinclause involving the given relation and anything else.
3440 *
3441 * This is the same as have_relevant_eclass_joinclause with the other rel
3442 * implicitly defined as "everything else in the query".
3443 */
3444bool
3445has_relevant_eclass_joinclause(PlannerInfo *root, RelOptInfo *rel1)
3446{
3447 Bitmapset *matched_ecs;
3448 int i;
3449
3450 /* Examine only eclasses mentioning rel1 */
3451 matched_ecs = get_eclass_indexes_for_relids(root, rel1->relids);
3452
3453 i = -1;
3454 while ((i = bms_next_member(matched_ecs, i)) >= 0)
3455 {
3456 EquivalenceClass *ec = (EquivalenceClass *) list_nth(root->eq_classes,
3457 i);
3458
3459 /*
3460 * Won't generate joinclauses if single-member (this test covers the
3461 * volatile case too)
3462 */
3463 if (list_length(ec->ec_members) <= 1)
3464 continue;
3465
3466 /*
3467 * Per the comment in have_relevant_eclass_joinclause, it's sufficient
3468 * to find an EC that mentions both this rel and some other rel.
3469 */
3470 if (!bms_is_subset(ec->ec_relids, rel1->relids))
3471 return true;
3472 }
3473
3474 return false;
3475}
3476
3477
3478/*
3479 * eclass_useful_for_merging
3480 * Detect whether the EC could produce any mergejoinable join clauses
3481 * against the specified relation.
3482 *
3483 * This is just a heuristic test and doesn't have to be exact; it's better
3484 * to say "yes" incorrectly than "no". Hence we don't bother with details
3485 * like whether the lack of a cross-type operator might prevent the clause
3486 * from actually being generated.
3487 */
3488bool
3489eclass_useful_for_merging(PlannerInfo *root,
3490 EquivalenceClass *eclass,
3491 RelOptInfo *rel)
3492{
3493 Relids relids;
3494 ListCell *lc;
3495
3496 Assert(!eclass->ec_merged);
3497
3498 /*
3499 * Won't generate joinclauses if const or single-member (the latter test
3500 * covers the volatile case too)
3501 */
3502 if (eclass->ec_has_const || list_length(eclass->ec_members) <= 1)
3503 return false;
3504
3505 /*
3506 * Note we don't test ec_broken; if we did, we'd need a separate code path
3507 * to look through ec_sources. Checking the members anyway is OK as a
3508 * possibly-overoptimistic heuristic.
3509 */
3510
3511 /* If specified rel is a child, we must consider the topmost parent rel */
3512 if (IS_OTHER_REL(rel))
3513 {
3514 Assert(!bms_is_empty(rel->top_parent_relids));
3515 relids = rel->top_parent_relids;
3516 }
3517 else
3518 relids = rel->relids;
3519
3520 /* If rel already includes all members of eclass, no point in searching */
3521 if (bms_is_subset(eclass->ec_relids, relids))
3522 return false;
3523
3524 /*
3525 * To join, we need a member not in the given rel. Ignore children here.
3526 */
3527 foreach(lc, eclass->ec_members)
3528 {
3529 EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc);
3530
3531 /* Child members should not exist in ec_members */
3532 Assert(!cur_em->em_is_child);
3533
3534 if (!bms_overlap(cur_em->em_relids, relids))
3535 return true;
3536 }
3537
3538 return false;
3539}
3540
3541
3542/*
3543 * is_redundant_derived_clause
3544 * Test whether rinfo is derived from same EC as any clause in clauselist;
3545 * if so, it can be presumed to represent a condition that's redundant
3546 * with that member of the list.
3547 */
3548bool
3549is_redundant_derived_clause(RestrictInfo *rinfo, List *clauselist)
3550{
3551 EquivalenceClass *parent_ec = rinfo->parent_ec;
3552 ListCell *lc;
3553
3554 /* Fail if it's not a potentially-redundant clause from some EC */
3555 if (parent_ec == NULL)
3556 return false;
3557
3558 foreach(lc, clauselist)
3559 {
3560 RestrictInfo *otherrinfo = (RestrictInfo *) lfirst(lc);
3561
3562 if (otherrinfo->parent_ec == parent_ec)
3563 return true;
3564 }
3565
3566 return false;
3567}
3568
3569/*
3570 * is_redundant_with_indexclauses
3571 * Test whether rinfo is redundant with any clause in the IndexClause
3572 * list. Here, for convenience, we test both simple identity and
3573 * whether it is derived from the same EC as any member of the list.
3574 */
3575bool
3576is_redundant_with_indexclauses(RestrictInfo *rinfo, List *indexclauses)
3577{
3578 EquivalenceClass *parent_ec = rinfo->parent_ec;
3579 ListCell *lc;
3580
3581 foreach(lc, indexclauses)
3582 {
3583 IndexClause *iclause = lfirst_node(IndexClause, lc);
3584 RestrictInfo *otherrinfo = iclause->rinfo;
3585
3586 /* If indexclause is lossy, it won't enforce the condition exactly */
3587 if (iclause->lossy)
3588 continue;
3589
3590 /* Match if it's same clause (pointer equality should be enough) */
3591 if (rinfo == otherrinfo)
3592 return true;
3593 /* Match if derived from same EC */
3594 if (parent_ec && otherrinfo->parent_ec == parent_ec)
3595 return true;
3596
3597 /*
3598 * No need to look at the derived clauses in iclause->indexquals; they
3599 * couldn't match if the parent clause didn't.
3600 */
3601 }
3602
3603 return false;
3604}
3605
3606/*
3607 * get_eclass_indexes_for_relids
3608 * Build and return a Bitmapset containing the indexes into root's
3609 * eq_classes list for all eclasses that mention any of these relids
3610 */
3611static Bitmapset *
3612get_eclass_indexes_for_relids(PlannerInfo *root, Relids relids)
3613{
3614 Bitmapset *ec_indexes = NULL;
3615 int i = -1;
3616
3617 /* Should be OK to rely on eclass_indexes */
3618 Assert(root->ec_merging_done);
3619
3620 while ((i = bms_next_member(relids, i)) > 0)
3621 {
3622 RelOptInfo *rel = root->simple_rel_array[i];
3623
3624 /* ignore the RTE_GROUP RTE */
3625 if (i == root->group_rtindex)
3626 continue;
3627
3628 if (rel == NULL) /* must be an outer join */
3629 {
3630 Assert(bms_is_member(i, root->outer_join_rels));
3631 continue;
3632 }
3633
3634 ec_indexes = bms_add_members(ec_indexes, rel->eclass_indexes);
3635 }
3636 return ec_indexes;
3637}
3638
3639/*
3640 * get_common_eclass_indexes
3641 * Build and return a Bitmapset containing the indexes into root's
3642 * eq_classes list for all eclasses that mention rels in both
3643 * relids1 and relids2.
3644 */
3645static Bitmapset *
3646get_common_eclass_indexes(PlannerInfo *root, Relids relids1, Relids relids2)
3647{
3648 Bitmapset *rel1ecs;
3649 Bitmapset *rel2ecs;
3650 int relid;
3651
3652 rel1ecs = get_eclass_indexes_for_relids(root, relids1);
3653
3654 /*
3655 * We can get away with just using the relation's eclass_indexes directly
3656 * when relids2 is a singleton set.
3657 */
3658 if (bms_get_singleton_member(relids2, &relid))
3659 rel2ecs = root->simple_rel_array[relid]->eclass_indexes;
3660 else
3661 rel2ecs = get_eclass_indexes_for_relids(root, relids2);
3662
3663 /* Calculate and return the common EC indexes, recycling the left input. */
3664 return bms_int_members(rel1ecs, rel2ecs);
3665}
3666
3667/*
3668 * ec_build_derives_hash
3669 * Construct the auxiliary hash table for derived clause lookups.
3670 */
3671static void
3672ec_build_derives_hash(PlannerInfo *root, EquivalenceClass *ec)
3673{
3674 Assert(!ec->ec_derives_hash);
3675
3676 /*
3677 * Create the hash table.
3678 *
3679 * We pass list_length(ec->ec_derives_list) as the initial size.
3680 * Simplehash will divide this by the fillfactor (typically 0.9) and round
3681 * up to the next power of two, so this will usually give us at least 64
3682 * buckets around the threshold. That avoids immediate resizing without
3683 * hardcoding a specific size.
3684 */
3685 ec->ec_derives_hash = derives_create(root->planner_cxt,
3686 list_length(ec->ec_derives_list),
3687 NULL);
3688
3689 foreach_node(RestrictInfo, rinfo, ec->ec_derives_list)
3690 ec_add_clause_to_derives_hash(ec, rinfo);
3691}
3692
3693/*
3694 * ec_add_derived_clause
3695 * Add a clause to the set of derived clauses for the given
3696 * EquivalenceClass. Always appends to ec_derives_list; also adds
3697 * to ec_derives_hash if it exists.
3698 *
3699 * Also asserts expected invariants of derived clauses.
3700 */
3701static void
3702ec_add_derived_clause(EquivalenceClass *ec, RestrictInfo *clause)
3703{
3704 /*
3705 * Constant, if present, is always placed on the RHS; see
3706 * generate_base_implied_equalities_const(). LHS is never a constant.
3707 */
3708 Assert(!clause->left_em->em_is_const);
3709
3710 /*
3711 * Clauses containing a constant are never considered redundant, so
3712 * parent_ec is not set.
3713 */
3714 Assert(!clause->parent_ec || !clause->right_em->em_is_const);
3715
3716 ec->ec_derives_list = lappend(ec->ec_derives_list, clause);
3717 if (ec->ec_derives_hash)
3718 ec_add_clause_to_derives_hash(ec, clause);
3719}
3720
3721/*
3722 * ec_add_derived_clauses
3723 * Add a list of clauses to the set of clauses derived from the given
3724 * EquivalenceClass; adding to the list and hash table if needed.
3725 *
3726 * This function is similar to ec_add_derived_clause() but optimized for adding
3727 * multiple clauses at a time to the ec_derives_list. The assertions from
3728 * ec_add_derived_clause() are not repeated here, as the input clauses are
3729 * assumed to have already been validated.
3730 */
3731static void
3732ec_add_derived_clauses(EquivalenceClass *ec, List *clauses)
3733{
3734 ec->ec_derives_list = list_concat(ec->ec_derives_list, clauses);
3735 if (ec->ec_derives_hash)
3736 foreach_node(RestrictInfo, rinfo, clauses)
3737 ec_add_clause_to_derives_hash(ec, rinfo);
3738}
3739
3740/*
3741 * fill_ec_derives_key
3742 * Compute a canonical key for ec_derives_hash lookup or insertion.
3743 *
3744 * Derived clauses are looked up using a pair of EquivalenceMembers and a
3745 * parent EquivalenceClass. To avoid storing or searching for both EM orderings,
3746 * we canonicalize the key:
3747 *
3748 * - For clauses involving two non-constant EMs, em1 is set to the EM with lower
3749 * memory address and em2 is set to the other one.
3750 * - For clauses involving a constant EM, the caller must pass the non-constant
3751 * EM as leftem and NULL as rightem; we then set em1 = NULL and em2 = leftem.
3752 */
3753static inline void
3754fill_ec_derives_key(ECDerivesKey *key,
3755 EquivalenceMember *leftem,
3756 EquivalenceMember *rightem,
3757 EquivalenceClass *parent_ec)
3758{
3759 Assert(leftem); /* Always required for lookup or insertion */
3760
3761 if (rightem == NULL)
3762 {
3763 key->em1 = NULL;
3764 key->em2 = leftem;
3765 }
3766 else if (leftem < rightem)
3767 {
3768 key->em1 = leftem;
3769 key->em2 = rightem;
3770 }
3771 else
3772 {
3773 key->em1 = rightem;
3774 key->em2 = leftem;
3775 }
3776 key->parent_ec = parent_ec;
3777}
3778
3779/*
3780 * ec_add_clause_to_derives_hash
3781 * Add a derived clause to ec_derives_hash in the given EquivalenceClass.
3782 *
3783 * Each clause is associated with a canonicalized key. For constant-containing
3784 * clauses, only the non-constant EM is used for lookup; see comments in
3785 * fill_ec_derives_key().
3786 */
3787static void
3788ec_add_clause_to_derives_hash(EquivalenceClass *ec, RestrictInfo *rinfo)
3789{
3790 ECDerivesKey key;
3791 ECDerivesEntry *entry;
3792 bool found;
3793
3794 /*
3795 * Constants are always placed on the RHS; see
3796 * generate_base_implied_equalities_const().
3797 */
3798 Assert(!rinfo->left_em->em_is_const);
3799
3800 /*
3801 * Clauses containing a constant are never considered redundant, so
3802 * parent_ec is not set.
3803 */
3804 Assert(!rinfo->parent_ec || !rinfo->right_em->em_is_const);
3805
3806 /*
3807 * See fill_ec_derives_key() for details: we use a canonicalized key to
3808 * avoid storing both EM orderings. For constant EMs, only the
3809 * non-constant EM is included in the key.
3810 */
3811 fill_ec_derives_key(&key,
3812 rinfo->left_em,
3813 rinfo->right_em->em_is_const ? NULL : rinfo->right_em,
3814 rinfo->parent_ec);
3815 entry = derives_insert(ec->ec_derives_hash, key, &found);
3816 Assert(!found);
3817 entry->rinfo = rinfo;
3818}
3819
3820/*
3821 * ec_clear_derived_clauses
3822 * Reset ec_derives_list and ec_derives_hash.
3823 *
3824 * We destroy the hash table explicitly, since it may consume significant
3825 * space. The list holds the same set of entries and can become equally large
3826 * when thousands of partitions are involved, so we free it as well -- even
3827 * though we do not typically free lists.
3828 */
3829void
3830ec_clear_derived_clauses(EquivalenceClass *ec)
3831{
3832 list_free(ec->ec_derives_list);
3833 ec->ec_derives_list = NIL;
3834
3835 if (ec->ec_derives_hash)
3836 {
3837 derives_destroy(ec->ec_derives_hash);
3838 ec->ec_derives_hash = NULL;
3839 }
3840}
3841
3842/*
3843 * ec_search_clause_for_ems
3844 * Search for an existing RestrictInfo that equates the given pair
3845 * of EquivalenceMembers, either from ec_sources or ec_derives.
3846 *
3847 * Returns a clause with matching operands in either given order or commuted
3848 * order. We used to require matching operator OIDs, but dropped that since any
3849 * semantically different operator here would indicate a broken operator family.
3850 *
3851 * Returns NULL if no matching clause is found.
3852 */
3853static RestrictInfo *
3854ec_search_clause_for_ems(PlannerInfo *root, EquivalenceClass *ec,
3855 EquivalenceMember *leftem, EquivalenceMember *rightem,
3856 EquivalenceClass *parent_ec)
3857{
3858 /* Check original source clauses */
3859 foreach_node(RestrictInfo, rinfo, ec->ec_sources)
3860 {
3861 if (rinfo->left_em == leftem &&
3862 rinfo->right_em == rightem &&
3863 rinfo->parent_ec == parent_ec)
3864 return rinfo;
3865 if (rinfo->left_em == rightem &&
3866 rinfo->right_em == leftem &&
3867 rinfo->parent_ec == parent_ec)
3868 return rinfo;
3869 }
3870
3871 /* Not found in ec_sources; search derived clauses */
3872 return ec_search_derived_clause_for_ems(root, ec, leftem, rightem,
3873 parent_ec);
3874}
3875
3876/*
3877 * ec_search_derived_clause_for_ems
3878 * Search for an existing derived clause between two EquivalenceMembers.
3879 *
3880 * If the number of derived clauses exceeds a threshold, switch to hash table
3881 * lookup; otherwise, scan ec_derives_list linearly.
3882 *
3883 * Clauses involving constants are looked up by passing the non-constant EM
3884 * as leftem and setting rightem to NULL. In that case, we expect to find a
3885 * clause with a constant on the RHS.
3886 *
3887 * While searching the list, we compare each given EM with both sides of each
3888 * clause. But for hash table lookups, we construct a canonicalized key and
3889 * perform a single lookup.
3890 */
3891static RestrictInfo *
3892ec_search_derived_clause_for_ems(PlannerInfo *root, EquivalenceClass *ec,
3893 EquivalenceMember *leftem,
3894 EquivalenceMember *rightem,
3895 EquivalenceClass *parent_ec)
3896{
3897 /* Switch to using hash lookup when list grows "too long". */
3898 if (!ec->ec_derives_hash &&
3899 list_length(ec->ec_derives_list) >= EC_DERIVES_HASH_THRESHOLD)
3900 ec_build_derives_hash(root, ec);
3901
3902 /* Perform hash table lookup if available */
3903 if (ec->ec_derives_hash)
3904 {
3905 ECDerivesKey key;
3906 RestrictInfo *rinfo;
3907 ECDerivesEntry *entry;
3908
3909 fill_ec_derives_key(&key, leftem, rightem, parent_ec);
3910 entry = derives_lookup(ec->ec_derives_hash, key);
3911 if (entry)
3912 {
3913 rinfo = entry->rinfo;
3914 Assert(rinfo);
3915 Assert(rightem || rinfo->right_em->em_is_const);
3916 return rinfo;
3917 }
3918 }
3919 else
3920 {
3921 /* Fallback to linear search over ec_derives_list */
3922 foreach_node(RestrictInfo, rinfo, ec->ec_derives_list)
3923 {
3924 /* Handle special case: lookup by non-const EM alone */
3925 if (!rightem &&
3926 rinfo->left_em == leftem)
3927 {
3928 Assert(rinfo->right_em->em_is_const);
3929 return rinfo;
3930 }
3931 if (rinfo->left_em == leftem &&
3932 rinfo->right_em == rightem &&
3933 rinfo->parent_ec == parent_ec)
3934 return rinfo;
3935 if (rinfo->left_em == rightem &&
3936 rinfo->right_em == leftem &&
3937 rinfo->parent_ec == parent_ec)
3938 return rinfo;
3939 }
3940 }
3941
3942 return NULL;
3943}
adjust_appendrel_attrs
Node * adjust_appendrel_attrs(PlannerInfo *root, Node *node, int nappinfos, AppendRelInfo **appinfos)
Definition appendinfo.c:200
adjust_appendrel_attrs_multilevel
Node * adjust_appendrel_attrs_multilevel(PlannerInfo *root, Node *node, RelOptInfo *childrel, RelOptInfo *parentrel)
Definition appendinfo.c:592
AttrNumber
int16 AttrNumber
Definition attnum.h:21
bms_difference
Bitmapset * bms_difference(const Bitmapset *a, const Bitmapset *b)
Definition bitmapset.c:346
bms_make_singleton
Bitmapset * bms_make_singleton(int x)
Definition bitmapset.c:216
bms_int_members
Bitmapset * bms_int_members(Bitmapset *a, const Bitmapset *b)
Definition bitmapset.c:1108
bms_intersect
Bitmapset * bms_intersect(const Bitmapset *a, const Bitmapset *b)
Definition bitmapset.c:292
bms_equal
bool bms_equal(const Bitmapset *a, const Bitmapset *b)
Definition bitmapset.c:142
bms_next_member
int bms_next_member(const Bitmapset *a, int prevbit)
Definition bitmapset.c:1305
bms_add_range
Bitmapset * bms_add_range(Bitmapset *a, int lower, int upper)
Definition bitmapset.c:1018
bms_is_subset
bool bms_is_subset(const Bitmapset *a, const Bitmapset *b)
Definition bitmapset.c:412
bms_is_member
bool bms_is_member(int x, const Bitmapset *a)
Definition bitmapset.c:510
bms_add_member
Bitmapset * bms_add_member(Bitmapset *a, int x)
Definition bitmapset.c:814
bms_add_members
Bitmapset * bms_add_members(Bitmapset *a, const Bitmapset *b)
Definition bitmapset.c:916
bms_union
Bitmapset * bms_union(const Bitmapset *a, const Bitmapset *b)
Definition bitmapset.c:251
bms_membership
BMS_Membership bms_membership(const Bitmapset *a)
Definition bitmapset.c:780
bms_overlap
bool bms_overlap(const Bitmapset *a, const Bitmapset *b)
Definition bitmapset.c:581
bms_get_singleton_member
bool bms_get_singleton_member(const Bitmapset *a, int *member)
Definition bitmapset.c:714
bms_join
Bitmapset * bms_join(Bitmapset *a, Bitmapset *b)
Definition bitmapset.c:1229
bms_copy
Bitmapset * bms_copy(const Bitmapset *a)
Definition bitmapset.c:122
bms_is_empty
#define bms_is_empty(a)
Definition bitmapset.h:118
BMS_MULTIPLE
@ BMS_MULTIPLE
Definition bitmapset.h:73
Min
#define Min(x, y)
Definition c.h:997
Max
#define Max(x, y)
Definition c.h:991
Assert
#define Assert(condition)
Definition c.h:873
int32
int32_t int32
Definition c.h:542
unlikely
#define unlikely(x)
Definition c.h:412
uint32
uint32_t uint32
Definition c.h:546
Index
unsigned int Index
Definition c.h:628
OidIsValid
#define OidIsValid(objectId)
Definition c.h:788
contain_agg_clause
bool contain_agg_clause(Node *clause)
Definition clauses.c:190
contain_window_function
bool contain_window_function(Node *clause)
Definition clauses.c:227
is_parallel_safe
bool is_parallel_safe(PlannerInfo *root, Node *node)
Definition clauses.c:762
contain_volatile_functions
bool contain_volatile_functions(Node *clause)
Definition clauses.c:547
COMPARE_EQ
@ COMPARE_EQ
Definition cmptype.h:36
ERROR
#define ERROR
Definition elog.h:39
elog
#define elog(elevel,...)
Definition elog.h:226
equal
bool equal(const void *a, const void *b)
Definition equalfuncs.c:223
rebuild_eclass_attr_needed
void rebuild_eclass_attr_needed(PlannerInfo *root)
Definition equivclass.c:2573
get_eclass_for_sort_expr
EquivalenceClass * get_eclass_for_sort_expr(PlannerInfo *root, Expr *expr, List *opfamilies, Oid opcintype, Oid collation, Index sortref, Relids rel, bool create_it)
Definition equivclass.c:736
add_child_rel_equivalences
void add_child_rel_equivalences(PlannerInfo *root, AppendRelInfo *appinfo, RelOptInfo *parent_rel, RelOptInfo *child_rel)
Definition equivclass.c:2832
is_redundant_with_indexclauses
bool is_redundant_with_indexclauses(RestrictInfo *rinfo, List *indexclauses)
Definition equivclass.c:3576
generate_base_implied_equalities
void generate_base_implied_equalities(PlannerInfo *root)
Definition equivclass.c:1187
exprs_known_equal
bool exprs_known_equal(PlannerInfo *root, Node *item1, Node *item2, Oid opfamily)
Definition equivclass.c:2647
generate_join_implied_equalities_normal
static List * generate_join_implied_equalities_normal(PlannerInfo *root, EquivalenceClass *ec, Relids join_relids, Relids outer_relids, Relids inner_relids)
Definition equivclass.c:1720
ec_search_derived_clause_for_ems
static RestrictInfo * ec_search_derived_clause_for_ems(PlannerInfo *root, EquivalenceClass *ec, EquivalenceMember *leftem, EquivalenceMember *rightem, EquivalenceClass *parent_ec)
Definition equivclass.c:3892
ec_build_derives_hash
static void ec_build_derives_hash(PlannerInfo *root, EquivalenceClass *ec)
Definition equivclass.c:3672
canonicalize_ec_expression
Expr * canonicalize_ec_expression(Expr *expr, Oid req_type, Oid req_collation)
Definition equivclass.c:545
find_ec_member_matching_expr
EquivalenceMember * find_ec_member_matching_expr(EquivalenceClass *ec, Expr *expr, Relids relids)
Definition equivclass.c:916
ec_add_clause_to_derives_hash
static void ec_add_clause_to_derives_hash(EquivalenceClass *ec, RestrictInfo *rinfo)
Definition equivclass.c:3788
find_join_domain
static JoinDomain * find_join_domain(PlannerInfo *root, Relids relids)
Definition equivclass.c:2616
relation_can_be_sorted_early
bool relation_can_be_sorted_early(PlannerInfo *root, RelOptInfo *rel, EquivalenceClass *ec, bool require_parallel_safe)
Definition equivclass.c:1076
setup_eclass_member_iterator
void setup_eclass_member_iterator(EquivalenceMemberIterator *it, EquivalenceClass *ec, Relids child_relids)
Definition equivclass.c:3155
generate_base_implied_equalities_broken
static void generate_base_implied_equalities_broken(PlannerInfo *root, EquivalenceClass *ec)
Definition equivclass.c:1486
ec_clear_derived_clauses
void ec_clear_derived_clauses(EquivalenceClass *ec)
Definition equivclass.c:3830
ec_add_derived_clause
static void ec_add_derived_clause(EquivalenceClass *ec, RestrictInfo *clause)
Definition equivclass.c:3702
process_equivalence
bool process_equivalence(PlannerInfo *root, RestrictInfo **p_restrictinfo, JoinDomain *jdomain)
Definition equivclass.c:179
generate_implied_equalities_for_column
List * generate_implied_equalities_for_column(PlannerInfo *root, RelOptInfo *rel, ec_matches_callback_type callback, void *callback_arg, Relids prohibited_rels)
Definition equivclass.c:3238
add_child_eq_member
static EquivalenceMember * add_child_eq_member(PlannerInfo *root, EquivalenceClass *ec, int ec_index, Expr *expr, Relids relids, JoinDomain *jdomain, EquivalenceMember *parent_em, Oid datatype, Index child_relid)
Definition equivclass.c:661
EC_DERIVES_HASH_THRESHOLD
#define EC_DERIVES_HASH_THRESHOLD
Definition equivclass.c:124
eclass_member_iterator_next
EquivalenceMember * eclass_member_iterator_next(EquivalenceMemberIterator *it)
Definition equivclass.c:3174
have_relevant_eclass_joinclause
bool have_relevant_eclass_joinclause(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
Definition equivclass.c:3369
find_computable_ec_member
EquivalenceMember * find_computable_ec_member(PlannerInfo *root, EquivalenceClass *ec, List *exprs, Relids relids, bool require_parallel_safe)
Definition equivclass.c:991
get_common_eclass_indexes
static Bitmapset * get_common_eclass_indexes(PlannerInfo *root, Relids relids1, Relids relids2)
Definition equivclass.c:3646
generate_join_implied_equalities_for_ecs
List * generate_join_implied_equalities_for_ecs(PlannerInfo *root, List *eclasses, Relids join_relids, Relids outer_relids, RelOptInfo *inner_rel)
Definition equivclass.c:1649
add_setop_child_rel_equivalences
void add_setop_child_rel_equivalences(PlannerInfo *root, RelOptInfo *child_rel, List *child_tlist, List *setop_pathkeys)
Definition equivclass.c:3083
fill_ec_derives_key
static void fill_ec_derives_key(ECDerivesKey *key, EquivalenceMember *leftem, EquivalenceMember *rightem, EquivalenceClass *parent_ec)
Definition equivclass.c:3754
reconsider_outer_join_clauses
void reconsider_outer_join_clauses(PlannerInfo *root)
Definition equivclass.c:2134
eclass_useful_for_merging
bool eclass_useful_for_merging(PlannerInfo *root, EquivalenceClass *eclass, RelOptInfo *rel)
Definition equivclass.c:3489
add_child_join_rel_equivalences
void add_child_join_rel_equivalences(PlannerInfo *root, int nappinfos, AppendRelInfo **appinfos, RelOptInfo *parent_joinrel, RelOptInfo *child_joinrel)
Definition equivclass.c:2940
create_join_clause
static RestrictInfo * create_join_clause(PlannerInfo *root, EquivalenceClass *ec, Oid opno, EquivalenceMember *leftem, EquivalenceMember *rightem, EquivalenceClass *parent_ec)
Definition equivclass.c:1982
ec_add_derived_clauses
static void ec_add_derived_clauses(EquivalenceClass *ec, List *clauses)
Definition equivclass.c:3732
get_eclass_indexes_for_relids
static Bitmapset * get_eclass_indexes_for_relids(PlannerInfo *root, Relids relids)
Definition equivclass.c:3612
is_redundant_derived_clause
bool is_redundant_derived_clause(RestrictInfo *rinfo, List *clauselist)
Definition equivclass.c:3549
find_derived_clause_for_ec_member
RestrictInfo * find_derived_clause_for_ec_member(PlannerInfo *root, EquivalenceClass *ec, EquivalenceMember *em)
Definition equivclass.c:2803
ec_search_clause_for_ems
static RestrictInfo * ec_search_clause_for_ems(PlannerInfo *root, EquivalenceClass *ec, EquivalenceMember *leftem, EquivalenceMember *rightem, EquivalenceClass *parent_ec)
Definition equivclass.c:3854
generate_base_implied_equalities_no_const
static void generate_base_implied_equalities_no_const(PlannerInfo *root, EquivalenceClass *ec)
Definition equivclass.c:1370
generate_base_implied_equalities_const
static void generate_base_implied_equalities_const(PlannerInfo *root, EquivalenceClass *ec)
Definition equivclass.c:1271
select_equality_operator
static Oid select_equality_operator(EquivalenceClass *ec, Oid lefttype, Oid righttype)
Definition equivclass.c:1947
match_eclasses_to_foreign_key_col
EquivalenceClass * match_eclasses_to_foreign_key_col(PlannerInfo *root, ForeignKeyOptInfo *fkinfo, int colno)
Definition equivclass.c:2709
make_eq_member
static EquivalenceMember * make_eq_member(EquivalenceClass *ec, Expr *expr, Relids relids, JoinDomain *jdomain, EquivalenceMember *parent, Oid datatype)
Definition equivclass.c:592
reconsider_outer_join_clause
static bool reconsider_outer_join_clause(PlannerInfo *root, OuterJoinClauseInfo *ojcinfo, bool outer_on_left)
Definition equivclass.c:2256
generate_join_implied_equalities
List * generate_join_implied_equalities(PlannerInfo *root, Relids join_relids, Relids outer_relids, RelOptInfo *inner_rel, SpecialJoinInfo *sjinfo)
Definition equivclass.c:1549
add_eq_member
static EquivalenceMember * add_eq_member(EquivalenceClass *ec, Expr *expr, Relids relids, JoinDomain *jdomain, Oid datatype)
Definition equivclass.c:628
has_relevant_eclass_joinclause
bool has_relevant_eclass_joinclause(PlannerInfo *root, RelOptInfo *rel1)
Definition equivclass.c:3445
reconsider_full_join_clause
static bool reconsider_full_join_clause(PlannerInfo *root, OuterJoinClauseInfo *ojcinfo)
Definition equivclass.c:2383
generate_join_implied_equalities_broken
static List * generate_join_implied_equalities_broken(PlannerInfo *root, EquivalenceClass *ec, Relids nominal_join_relids, Relids outer_relids, Relids nominal_inner_relids, RelOptInfo *inner_rel)
Definition equivclass.c:1898
palloc0_array
#define palloc0_array(type, count)
Definition fe_memutils.h:77
distribute_restrictinfo_to_rels
void distribute_restrictinfo_to_rels(PlannerInfo *root, RestrictInfo *restrictinfo)
Definition initsplan.c:3558
build_implied_join_equality
RestrictInfo * build_implied_join_equality(PlannerInfo *root, Oid opno, Oid collation, Expr *item1, Expr *item2, Relids qualscope, Index security_level)
Definition initsplan.c:3787
add_vars_to_targetlist
void add_vars_to_targetlist(PlannerInfo *root, List *vars, Relids where_needed)
Definition initsplan.c:289
process_implied_equality
RestrictInfo * process_implied_equality(PlannerInfo *root, Oid opno, Oid collation, Expr *item1, Expr *item2, Relids qualscope, Index security_level, bool both_const)
Definition initsplan.c:3643
add_vars_to_attr_needed
void add_vars_to_attr_needed(PlannerInfo *root, List *vars, Relids where_needed)
Definition initsplan.c:360
i
int i
Definition isn.c:77
add_outer_joins_to_relids
Relids add_outer_joins_to_relids(PlannerInfo *root, Relids input_relids, SpecialJoinInfo *sjinfo, List **pushed_down_joins)
Definition joinrels.c:800
lappend
List * lappend(List *list, void *datum)
Definition list.c:339
list_delete_nth_cell
List * list_delete_nth_cell(List *list, int n)
Definition list.c:767
list_concat
List * list_concat(List *list1, const List *list2)
Definition list.c:561
list_copy
List * list_copy(const List *oldlist)
Definition list.c:1573
list_free
void list_free(List *list)
Definition list.c:1546
list_member_oid
bool list_member_oid(const List *list, Oid datum)
Definition list.c:722
list_member
bool list_member(const List *list, const void *datum)
Definition list.c:661
get_opfamily_member_for_cmptype
Oid get_opfamily_member_for_cmptype(Oid opfamily, Oid lefttype, Oid righttype, CompareType cmptype)
Definition lsyscache.c:197
op_hashjoinable
bool op_hashjoinable(Oid opno, Oid inputtype)
Definition lsyscache.c:1587
get_opcode
RegProcedure get_opcode(Oid opno)
Definition lsyscache.c:1435
func_strict
bool func_strict(Oid funcid)
Definition lsyscache.c:1911
get_func_leakproof
bool get_func_leakproof(Oid funcid)
Definition lsyscache.c:1987
get_mergejoin_opfamilies
List * get_mergejoin_opfamilies(Oid opno)
Definition lsyscache.c:428
op_input_types
void op_input_types(Oid opno, Oid *lefttype, Oid *righttype)
Definition lsyscache.c:1508
makeBoolConst
Node * makeBoolConst(bool value, bool isnull)
Definition makefuncs.c:408
pfree
void pfree(void *pointer)
Definition mcxt.c:1616
palloc0
void * palloc0(Size size)
Definition mcxt.c:1417
exprType
Oid exprType(const Node *expr)
Definition nodeFuncs.c:42
exprTypmod
int32 exprTypmod(const Node *expr)
Definition nodeFuncs.c:301
exprCollation
Oid exprCollation(const Node *expr)
Definition nodeFuncs.c:821
applyRelabelType
Node * applyRelabelType(Node *arg, Oid rtype, int32 rtypmod, Oid rcollid, CoercionForm rformat, int rlocation, bool overwrite_ok)
Definition nodeFuncs.c:636
expression_returns_set
bool expression_returns_set(Node *clause)
Definition nodeFuncs.c:763
set_opfuncid
void set_opfuncid(OpExpr *opexpr)
Definition nodeFuncs.c:1871
get_rightop
static Node * get_rightop(const void *clause)
Definition nodeFuncs.h:95
is_opclause
static bool is_opclause(const void *clause)
Definition nodeFuncs.h:76
get_leftop
static Node * get_leftop(const void *clause)
Definition nodeFuncs.h:83
IsA
#define IsA(nodeptr, _type_)
Definition nodes.h:164
copyObject
#define copyObject(obj)
Definition nodes.h:232
makeNode
#define makeNode(_type_)
Definition nodes.h:161
PVC_RECURSE_AGGREGATES
#define PVC_RECURSE_AGGREGATES
Definition optimizer.h:189
PVC_RECURSE_WINDOWFUNCS
#define PVC_RECURSE_WINDOWFUNCS
Definition optimizer.h:191
PVC_INCLUDE_WINDOWFUNCS
#define PVC_INCLUDE_WINDOWFUNCS
Definition optimizer.h:190
PVC_INCLUDE_PLACEHOLDERS
#define PVC_INCLUDE_PLACEHOLDERS
Definition optimizer.h:192
PVC_INCLUDE_AGGREGATES
#define PVC_INCLUDE_AGGREGATES
Definition optimizer.h:188
MemoryContextSwitchTo
static MemoryContext MemoryContextSwitchTo(MemoryContext context)
Definition palloc.h:124
repalloc0_array
#define repalloc0_array(pointer, type, oldcount, count)
Definition palloc.h:109
IS_SIMPLE_REL
#define IS_SIMPLE_REL(rel)
Definition pathnodes.h:971
IS_JOIN_REL
#define IS_JOIN_REL(rel)
Definition pathnodes.h:976
RELOPT_BASEREL
@ RELOPT_BASEREL
Definition pathnodes.h:959
RELOPT_OTHER_MEMBER_REL
@ RELOPT_OTHER_MEMBER_REL
Definition pathnodes.h:961
RELOPT_JOINREL
@ RELOPT_JOINREL
Definition pathnodes.h:960
RELOPT_OTHER_JOINREL
@ RELOPT_OTHER_JOINREL
Definition pathnodes.h:962
IS_OTHER_REL
#define IS_OTHER_REL(rel)
Definition pathnodes.h:986
ec_matches_callback_type
bool(* ec_matches_callback_type)(PlannerInfo *root, RelOptInfo *rel, EquivalenceClass *ec, EquivalenceMember *em, void *arg)
Definition paths.h:129
arg
void * arg
Definition pg_backup_utils.c:29
lfirst
#define lfirst(lc)
Definition pg_list.h:172
lfirst_node
#define lfirst_node(type, lc)
Definition pg_list.h:176
list_length
static int list_length(const List *l)
Definition pg_list.h:152
linitial_node
#define linitial_node(type, l)
Definition pg_list.h:181
NIL
#define NIL
Definition pg_list.h:68
foreach_current_index
#define foreach_current_index(var_or_cell)
Definition pg_list.h:403
foreach_delete_current
#define foreach_delete_current(lst, var_or_cell)
Definition pg_list.h:391
list_make1
#define list_make1(x1)
Definition pg_list.h:212
list_nth
static void * list_nth(const List *list, int n)
Definition pg_list.h:299
linitial
#define linitial(l)
Definition pg_list.h:178
lsecond
#define lsecond(l)
Definition pg_list.h:183
foreach_node
#define foreach_node(type, var, lst)
Definition pg_list.h:496
list_head
static ListCell * list_head(const List *l)
Definition pg_list.h:128
lnext
static ListCell * lnext(const List *l, const ListCell *c)
Definition pg_list.h:343
lfirst_oid
#define lfirst_oid(lc)
Definition pg_list.h:174
pg_type.h
InvalidOid
#define InvalidOid
Definition postgres_ext.h:37
Oid
unsigned int Oid
Definition postgres_ext.h:32
fb
static int fb(int x)
Definition preproc-init.c:92
COERCE_IMPLICIT_CAST
@ COERCE_IMPLICIT_CAST
Definition primnodes.h:768
IS_NOT_NULL
@ IS_NOT_NULL
Definition primnodes.h:1977
root
tree ctl root
Definition radixtree.h:1857
eclass
static struct cvec * eclass(struct vars *v, chr c, int cases)
Definition regc_locale.c:500
find_childrel_parents
Relids find_childrel_parents(PlannerInfo *root, RelOptInfo *rel)
Definition relnode.c:1657
make_restrictinfo
RestrictInfo * make_restrictinfo(PlannerInfo *root, Expr *clause, bool is_pushed_down, bool has_clone, bool is_clone, bool pseudoconstant, Index security_level, Relids required_relids, Relids incompatible_relids, Relids outer_relids)
Definition restrictinfo.c:52
remove_nulling_relids
Node * remove_nulling_relids(Node *node, const Bitmapset *removable_relids, const Bitmapset *except_relids)
Definition rewriteManip.c:1328
ECDerivesEntry::rinfo
RestrictInfo * rinfo
Definition equivclass.c:120
ECDerivesEntry::key
ECDerivesKey key
Definition equivclass.c:119
ECDerivesKey::parent_ec
EquivalenceClass * parent_ec
Definition equivclass.c:112
ECDerivesKey::em1
EquivalenceMember * em1
Definition equivclass.c:110
ECDerivesKey::em2
EquivalenceMember * em2
Definition equivclass.c:111
EquivalenceClass::ec_childmembers
List ** ec_childmembers
Definition pathnodes.h:1643
EquivalenceClass::ec_merged
struct EquivalenceClass * ec_merged
Definition pathnodes.h:1657
EquivalenceClass::ec_derives_hash
struct derives_hash * ec_derives_hash
Definition pathnodes.h:1646
EquivalenceClass::ec_derives_list
List * ec_derives_list
Definition pathnodes.h:1645
JoinDomain::jd_relids
Relids jd_relids
Definition pathnodes.h:1547
List
Definition pg_list.h:54
Node
Definition nodes.h:135
PathTarget::exprs
List * exprs
Definition pathnodes.h:1858
RelOptInfo::relids
Relids relids
Definition pathnodes.h:1003
RelOptInfo::reltarget
struct PathTarget * reltarget
Definition pathnodes.h:1027
RelOptInfo::top_parent_relids
Relids top_parent_relids
Definition pathnodes.h:1156
RelOptInfo::reloptkind
RelOptKind reloptkind
Definition pathnodes.h:997
RelOptInfo::eclass_indexes
Bitmapset * eclass_indexes
Definition pathnodes.h:1081
RelOptInfo::has_eclass_joins
bool has_eclass_joins
Definition pathnodes.h:1132
RestrictInfo::is_pushed_down
bool is_pushed_down
Definition pathnodes.h:2873
RestrictInfo::required_relids
Relids required_relids
Definition pathnodes.h:2901
RestrictInfo::outer_relids
Relids outer_relids
Definition pathnodes.h:2907
RestrictInfo::incompatible_relids
Relids incompatible_relids
Definition pathnodes.h:2904
RestrictInfo::clause
Expr * clause
Definition pathnodes.h:2870
SpecialJoinInfo::syn_lefthand
Relids syn_lefthand
Definition pathnodes.h:3197
SpecialJoinInfo::syn_righthand
Relids syn_righthand
Definition pathnodes.h:3198
Var::varattno
AttrNumber varattno
Definition primnodes.h:274
Var::varno
int varno
Definition primnodes.h:269
callback
static void callback(struct sockaddr *addr, struct sockaddr *mask, void *unused)
Definition test_ifaddrs.c:46
pull_varnos
Relids pull_varnos(PlannerInfo *root, Node *node)
Definition var.c:114
pull_var_clause
List * pull_var_clause(Node *node, int flags)
Definition var.c:653