Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * restrictinfo.c
4 : * RestrictInfo node manipulation routines.
5 : *
6 : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : *
10 : * IDENTIFICATION
11 : * src/backend/optimizer/util/restrictinfo.c
12 : *
13 : *-------------------------------------------------------------------------
14 : */
15 : #include "postgres.h"
16 :
17 : #include "nodes/makefuncs.h"
18 : #include "nodes/nodeFuncs.h"
19 : #include "optimizer/clauses.h"
20 : #include "optimizer/optimizer.h"
21 : #include "optimizer/restrictinfo.h"
22 :
23 :
24 : static Expr *make_sub_restrictinfos(PlannerInfo *root,
25 : Expr *clause,
26 : bool is_pushed_down,
27 : bool has_clone,
28 : bool is_clone,
29 : bool pseudoconstant,
30 : Index security_level,
31 : Relids required_relids,
32 : Relids incompatible_relids,
33 : Relids outer_relids);
34 :
35 :
36 : /*
37 : * make_restrictinfo
38 : *
39 : * Build a RestrictInfo node containing the given subexpression.
40 : *
41 : * The is_pushed_down, has_clone, is_clone, and pseudoconstant flags for the
42 : * RestrictInfo must be supplied by the caller, as well as the correct values
43 : * for security_level, incompatible_relids, and outer_relids.
44 : * required_relids can be NULL, in which case it defaults to the actual clause
45 : * contents (i.e., clause_relids).
46 : *
47 : * We initialize fields that depend only on the given subexpression, leaving
48 : * others that depend on context (or may never be needed at all) to be filled
49 : * later.
50 : */
51 : RestrictInfo *
52 400476 : make_restrictinfo(PlannerInfo *root,
53 : Expr *clause,
54 : bool is_pushed_down,
55 : bool has_clone,
56 : bool is_clone,
57 : bool pseudoconstant,
58 : Index security_level,
59 : Relids required_relids,
60 : Relids incompatible_relids,
61 : Relids outer_relids)
62 : {
63 : /*
64 : * If it's an OR clause, build a modified copy with RestrictInfos inserted
65 : * above each subclause of the top-level AND/OR structure.
66 : */
67 400476 : if (is_orclause(clause))
68 6457 : return (RestrictInfo *) make_sub_restrictinfos(root,
69 : clause,
70 : is_pushed_down,
71 : has_clone,
72 : is_clone,
73 : pseudoconstant,
74 : security_level,
75 : required_relids,
76 : incompatible_relids,
77 : outer_relids);
78 :
79 : /* Shouldn't be an AND clause, else AND/OR flattening messed up */
80 : Assert(!is_andclause(clause));
81 :
82 394019 : return make_plain_restrictinfo(root,
83 : clause,
84 : NULL,
85 : is_pushed_down,
86 : has_clone,
87 : is_clone,
88 : pseudoconstant,
89 : security_level,
90 : required_relids,
91 : incompatible_relids,
92 : outer_relids);
93 : }
94 :
95 : /*
96 : * make_plain_restrictinfo
97 : *
98 : * Common code for the main entry points and the recursive cases. Also,
99 : * useful while constructing RestrictInfos above OR clause, which already has
100 : * RestrictInfos above its subclauses.
101 : */
102 : RestrictInfo *
103 418250 : make_plain_restrictinfo(PlannerInfo *root,
104 : Expr *clause,
105 : Expr *orclause,
106 : bool is_pushed_down,
107 : bool has_clone,
108 : bool is_clone,
109 : bool pseudoconstant,
110 : Index security_level,
111 : Relids required_relids,
112 : Relids incompatible_relids,
113 : Relids outer_relids)
114 : {
115 418250 : RestrictInfo *restrictinfo = makeNode(RestrictInfo);
116 : Relids baserels;
117 :
118 418250 : restrictinfo->clause = clause;
119 418250 : restrictinfo->orclause = orclause;
120 418250 : restrictinfo->is_pushed_down = is_pushed_down;
121 418250 : restrictinfo->pseudoconstant = pseudoconstant;
122 418250 : restrictinfo->has_clone = has_clone;
123 418250 : restrictinfo->is_clone = is_clone;
124 418250 : restrictinfo->can_join = false; /* may get set below */
125 418250 : restrictinfo->security_level = security_level;
126 418250 : restrictinfo->incompatible_relids = incompatible_relids;
127 418250 : restrictinfo->outer_relids = outer_relids;
128 :
129 : /*
130 : * If it's potentially delayable by lower-level security quals, figure out
131 : * whether it's leakproof. We can skip testing this for level-zero quals,
132 : * since they would never get delayed on security grounds anyway.
133 : */
134 418250 : if (security_level > 0)
135 2593 : restrictinfo->leakproof = !contain_leaked_vars((Node *) clause);
136 : else
137 415657 : restrictinfo->leakproof = false; /* really, "don't know" */
138 :
139 : /*
140 : * Mark volatility as unknown. The contain_volatile_functions function
141 : * will determine if there are any volatile functions when called for the
142 : * first time with this RestrictInfo.
143 : */
144 418250 : restrictinfo->has_volatile = VOLATILITY_UNKNOWN;
145 :
146 : /*
147 : * If it's a binary opclause, set up left/right relids info. In any case
148 : * set up the total clause relids info.
149 : */
150 418250 : if (is_opclause(clause) && list_length(((OpExpr *) clause)->args) == 2)
151 : {
152 350116 : restrictinfo->left_relids = pull_varnos(root, get_leftop(clause));
153 350116 : restrictinfo->right_relids = pull_varnos(root, get_rightop(clause));
154 :
155 700232 : restrictinfo->clause_relids = bms_union(restrictinfo->left_relids,
156 350116 : restrictinfo->right_relids);
157 :
158 : /*
159 : * Does it look like a normal join clause, i.e., a binary operator
160 : * relating expressions that come from distinct relations? If so we
161 : * might be able to use it in a join algorithm. Note that this is a
162 : * purely syntactic test that is made regardless of context.
163 : */
164 350116 : if (!bms_is_empty(restrictinfo->left_relids) &&
165 344553 : !bms_is_empty(restrictinfo->right_relids) &&
166 139421 : !bms_overlap(restrictinfo->left_relids,
167 139421 : restrictinfo->right_relids))
168 : {
169 138192 : restrictinfo->can_join = true;
170 : /* pseudoconstant should certainly not be true */
171 : Assert(!restrictinfo->pseudoconstant);
172 : }
173 : }
174 : else
175 : {
176 : /* Not a binary opclause, so mark left/right relid sets as empty */
177 68134 : restrictinfo->left_relids = NULL;
178 68134 : restrictinfo->right_relids = NULL;
179 : /* and get the total relid set the hard way */
180 68134 : restrictinfo->clause_relids = pull_varnos(root, (Node *) clause);
181 : }
182 :
183 : /* required_relids defaults to clause_relids */
184 418250 : if (required_relids != NULL)
185 381847 : restrictinfo->required_relids = required_relids;
186 : else
187 36403 : restrictinfo->required_relids = restrictinfo->clause_relids;
188 :
189 : /*
190 : * Count the number of base rels appearing in clause_relids. To do this,
191 : * we just delete rels mentioned in root->outer_join_rels and count the
192 : * survivors. Because we are called during deconstruct_jointree which is
193 : * the same tree walk that populates outer_join_rels, this is a little bit
194 : * unsafe-looking; but it should be fine because the recursion in
195 : * deconstruct_jointree should already have visited any outer join that
196 : * could be mentioned in this clause.
197 : */
198 418250 : baserels = bms_difference(restrictinfo->clause_relids,
199 418250 : root->outer_join_rels);
200 418250 : restrictinfo->num_base_rels = bms_num_members(baserels);
201 418250 : bms_free(baserels);
202 :
203 : /*
204 : * Label this RestrictInfo with a fresh serial number.
205 : */
206 418250 : restrictinfo->rinfo_serial = ++(root->last_rinfo_serial);
207 :
208 : /*
209 : * Fill in all the cacheable fields with "not yet set" markers. None of
210 : * these will be computed until/unless needed. Note in particular that we
211 : * don't mark a binary opclause as mergejoinable or hashjoinable here;
212 : * that happens only if it appears in the right context (top level of a
213 : * joinclause list).
214 : */
215 418250 : restrictinfo->parent_ec = NULL;
216 :
217 418250 : restrictinfo->eval_cost.startup = -1;
218 418250 : restrictinfo->norm_selec = -1;
219 418250 : restrictinfo->outer_selec = -1;
220 :
221 418250 : restrictinfo->mergeopfamilies = NIL;
222 :
223 418250 : restrictinfo->left_ec = NULL;
224 418250 : restrictinfo->right_ec = NULL;
225 418250 : restrictinfo->left_em = NULL;
226 418250 : restrictinfo->right_em = NULL;
227 418250 : restrictinfo->scansel_cache = NIL;
228 :
229 418250 : restrictinfo->outer_is_left = false;
230 :
231 418250 : restrictinfo->hashjoinoperator = InvalidOid;
232 :
233 418250 : restrictinfo->left_bucketsize = -1;
234 418250 : restrictinfo->right_bucketsize = -1;
235 418250 : restrictinfo->left_mcvfreq = -1;
236 418250 : restrictinfo->right_mcvfreq = -1;
237 :
238 418250 : restrictinfo->left_hasheqoperator = InvalidOid;
239 418250 : restrictinfo->right_hasheqoperator = InvalidOid;
240 :
241 418250 : return restrictinfo;
242 : }
243 :
244 : /*
245 : * Recursively insert sub-RestrictInfo nodes into a boolean expression.
246 : *
247 : * We put RestrictInfos above simple (non-AND/OR) clauses and above
248 : * sub-OR clauses, but not above sub-AND clauses, because there's no need.
249 : * This may seem odd but it is closely related to the fact that we use
250 : * implicit-AND lists at top level of RestrictInfo lists. Only ORs and
251 : * simple clauses are valid RestrictInfos.
252 : *
253 : * The same is_pushed_down, has_clone, is_clone, and pseudoconstant flag
254 : * values can be applied to all RestrictInfo nodes in the result. Likewise
255 : * for security_level, incompatible_relids, and outer_relids.
256 : *
257 : * The given required_relids are attached to our top-level output,
258 : * but any OR-clause constituents are allowed to default to just the
259 : * contained rels.
260 : */
261 : static Expr *
262 25236 : make_sub_restrictinfos(PlannerInfo *root,
263 : Expr *clause,
264 : bool is_pushed_down,
265 : bool has_clone,
266 : bool is_clone,
267 : bool pseudoconstant,
268 : Index security_level,
269 : Relids required_relids,
270 : Relids incompatible_relids,
271 : Relids outer_relids)
272 : {
273 25236 : if (is_orclause(clause))
274 : {
275 6508 : List *orlist = NIL;
276 : ListCell *temp;
277 :
278 21325 : foreach(temp, ((BoolExpr *) clause)->args)
279 14817 : orlist = lappend(orlist,
280 14817 : make_sub_restrictinfos(root,
281 14817 : lfirst(temp),
282 : is_pushed_down,
283 : has_clone,
284 : is_clone,
285 : pseudoconstant,
286 : security_level,
287 : NULL,
288 : incompatible_relids,
289 : outer_relids));
290 6508 : return (Expr *) make_plain_restrictinfo(root,
291 : clause,
292 : make_orclause(orlist),
293 : is_pushed_down,
294 : has_clone,
295 : is_clone,
296 : pseudoconstant,
297 : security_level,
298 : required_relids,
299 : incompatible_relids,
300 : outer_relids);
301 : }
302 18728 : else if (is_andclause(clause))
303 : {
304 1757 : List *andlist = NIL;
305 : ListCell *temp;
306 :
307 5719 : foreach(temp, ((BoolExpr *) clause)->args)
308 3962 : andlist = lappend(andlist,
309 3962 : make_sub_restrictinfos(root,
310 3962 : lfirst(temp),
311 : is_pushed_down,
312 : has_clone,
313 : is_clone,
314 : pseudoconstant,
315 : security_level,
316 : required_relids,
317 : incompatible_relids,
318 : outer_relids));
319 1757 : return make_andclause(andlist);
320 : }
321 : else
322 16971 : return (Expr *) make_plain_restrictinfo(root,
323 : clause,
324 : NULL,
325 : is_pushed_down,
326 : has_clone,
327 : is_clone,
328 : pseudoconstant,
329 : security_level,
330 : required_relids,
331 : incompatible_relids,
332 : outer_relids);
333 : }
334 :
335 : /*
336 : * commute_restrictinfo
337 : *
338 : * Given a RestrictInfo containing a binary opclause, produce a RestrictInfo
339 : * representing the commutation of that clause. The caller must pass the
340 : * OID of the commutator operator (which it's presumably looked up, else
341 : * it would not know this is valid).
342 : *
343 : * Beware that the result shares sub-structure with the given RestrictInfo.
344 : * That's okay for the intended usage with derived index quals, but might
345 : * be hazardous if the source is subject to change. Also notice that we
346 : * assume without checking that the commutator op is a member of the same
347 : * btree and hash opclasses as the original op.
348 : */
349 : RestrictInfo *
350 41584 : commute_restrictinfo(RestrictInfo *rinfo, Oid comm_op)
351 : {
352 : RestrictInfo *result;
353 : OpExpr *newclause;
354 41584 : OpExpr *clause = castNode(OpExpr, rinfo->clause);
355 :
356 : Assert(list_length(clause->args) == 2);
357 :
358 : /* flat-copy all the fields of clause ... */
359 41584 : newclause = makeNode(OpExpr);
360 41584 : memcpy(newclause, clause, sizeof(OpExpr));
361 :
362 : /* ... and adjust those we need to change to commute it */
363 41584 : newclause->opno = comm_op;
364 41584 : newclause->opfuncid = InvalidOid;
365 41584 : newclause->args = list_make2(lsecond(clause->args),
366 : linitial(clause->args));
367 :
368 : /* likewise, flat-copy all the fields of rinfo ... */
369 41584 : result = makeNode(RestrictInfo);
370 41584 : memcpy(result, rinfo, sizeof(RestrictInfo));
371 :
372 : /*
373 : * ... and adjust those we need to change. Note in particular that we can
374 : * preserve any cached selectivity or cost estimates, since those ought to
375 : * be the same for the new clause. Likewise we can keep the source's
376 : * parent_ec. It's also important that we keep the same rinfo_serial.
377 : */
378 41584 : result->clause = (Expr *) newclause;
379 41584 : result->left_relids = rinfo->right_relids;
380 41584 : result->right_relids = rinfo->left_relids;
381 : Assert(result->orclause == NULL);
382 41584 : result->left_ec = rinfo->right_ec;
383 41584 : result->right_ec = rinfo->left_ec;
384 41584 : result->left_em = rinfo->right_em;
385 41584 : result->right_em = rinfo->left_em;
386 41584 : result->scansel_cache = NIL; /* not worth updating this */
387 41584 : if (rinfo->hashjoinoperator == clause->opno)
388 40523 : result->hashjoinoperator = comm_op;
389 : else
390 1061 : result->hashjoinoperator = InvalidOid;
391 41584 : result->left_bucketsize = rinfo->right_bucketsize;
392 41584 : result->right_bucketsize = rinfo->left_bucketsize;
393 41584 : result->left_mcvfreq = rinfo->right_mcvfreq;
394 41584 : result->right_mcvfreq = rinfo->left_mcvfreq;
395 41584 : result->left_hasheqoperator = InvalidOid;
396 41584 : result->right_hasheqoperator = InvalidOid;
397 :
398 41584 : return result;
399 : }
400 :
401 : /*
402 : * restriction_is_or_clause
403 : *
404 : * Returns t iff the restrictinfo node contains an 'or' clause.
405 : */
406 : bool
407 1210817 : restriction_is_or_clause(RestrictInfo *restrictinfo)
408 : {
409 1210817 : if (restrictinfo->orclause != NULL)
410 66126 : return true;
411 : else
412 1144691 : return false;
413 : }
414 :
415 : /*
416 : * restriction_is_securely_promotable
417 : *
418 : * Returns true if it's okay to evaluate this clause "early", that is before
419 : * other restriction clauses attached to the specified relation.
420 : */
421 : bool
422 908456 : restriction_is_securely_promotable(RestrictInfo *restrictinfo,
423 : RelOptInfo *rel)
424 : {
425 : /*
426 : * It's okay if there are no baserestrictinfo clauses for the rel that
427 : * would need to go before this one, *or* if this one is leakproof.
428 : */
429 908456 : if (restrictinfo->security_level <= rel->baserestrict_min_security ||
430 2626 : restrictinfo->leakproof)
431 907264 : return true;
432 : else
433 1192 : return false;
434 : }
435 :
436 : /*
437 : * Detect whether a RestrictInfo's clause is constant TRUE (note that it's
438 : * surely of type boolean). No such WHERE clause could survive qual
439 : * canonicalization, but equivclass.c may generate such RestrictInfos for
440 : * reasons discussed therein. We should drop them again when creating
441 : * the finished plan, which is handled by the next few functions.
442 : */
443 : static inline bool
444 204833 : rinfo_is_constant_true(RestrictInfo *rinfo)
445 : {
446 205910 : return IsA(rinfo->clause, Const) &&
447 205880 : !((Const *) rinfo->clause)->constisnull &&
448 1047 : DatumGetBool(((Const *) rinfo->clause)->constvalue);
449 : }
450 :
451 : /*
452 : * get_actual_clauses
453 : *
454 : * Returns a list containing the bare clauses from 'restrictinfo_list'.
455 : *
456 : * This is only to be used in cases where none of the RestrictInfos can
457 : * be pseudoconstant clauses (for instance, it's OK on indexqual lists).
458 : */
459 : List *
460 39953 : get_actual_clauses(List *restrictinfo_list)
461 : {
462 39953 : List *result = NIL;
463 : ListCell *l;
464 :
465 82249 : foreach(l, restrictinfo_list)
466 : {
467 42296 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, l);
468 :
469 : Assert(!rinfo->pseudoconstant);
470 : Assert(!rinfo_is_constant_true(rinfo));
471 :
472 42296 : result = lappend(result, rinfo->clause);
473 : }
474 39953 : return result;
475 : }
476 :
477 : /*
478 : * extract_actual_clauses
479 : *
480 : * Extract bare clauses from 'restrictinfo_list', returning either the
481 : * regular ones or the pseudoconstant ones per 'pseudoconstant'.
482 : * Constant-TRUE clauses are dropped in any case.
483 : */
484 : List *
485 385859 : extract_actual_clauses(List *restrictinfo_list,
486 : bool pseudoconstant)
487 : {
488 385859 : List *result = NIL;
489 : ListCell *l;
490 :
491 585287 : foreach(l, restrictinfo_list)
492 : {
493 199428 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, l);
494 :
495 199428 : if (rinfo->pseudoconstant == pseudoconstant &&
496 183516 : !rinfo_is_constant_true(rinfo))
497 183516 : result = lappend(result, rinfo->clause);
498 : }
499 385859 : return result;
500 : }
501 :
502 : /*
503 : * extract_actual_join_clauses
504 : *
505 : * Extract bare clauses from 'restrictinfo_list', separating those that
506 : * semantically match the join level from those that were pushed down.
507 : * Pseudoconstant and constant-TRUE clauses are excluded from the results.
508 : *
509 : * This is only used at outer joins, since for plain joins we don't care
510 : * about pushed-down-ness.
511 : */
512 : void
513 22492 : extract_actual_join_clauses(List *restrictinfo_list,
514 : Relids joinrelids,
515 : List **joinquals,
516 : List **otherquals)
517 : {
518 : ListCell *l;
519 :
520 22492 : *joinquals = NIL;
521 22492 : *otherquals = NIL;
522 :
523 45440 : foreach(l, restrictinfo_list)
524 : {
525 22948 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, l);
526 :
527 22948 : if (RINFO_IS_PUSHED_DOWN(rinfo, joinrelids))
528 : {
529 3505 : if (!rinfo->pseudoconstant &&
530 1874 : !rinfo_is_constant_true(rinfo))
531 1874 : *otherquals = lappend(*otherquals, rinfo->clause);
532 : }
533 : else
534 : {
535 : /* joinquals shouldn't have been marked pseudoconstant */
536 : Assert(!rinfo->pseudoconstant);
537 19443 : if (!rinfo_is_constant_true(rinfo))
538 18471 : *joinquals = lappend(*joinquals, rinfo->clause);
539 : }
540 : }
541 22492 : }
542 :
543 : /*
544 : * join_clause_is_movable_to
545 : * Test whether a join clause is a safe candidate for parameterization
546 : * of a scan on the specified base relation.
547 : *
548 : * A movable join clause is one that can safely be evaluated at a rel below
549 : * its normal semantic level (ie, its required_relids), if the values of
550 : * variables that it would need from other rels are provided.
551 : *
552 : * We insist that the clause actually reference the target relation; this
553 : * prevents undesirable movement of degenerate join clauses, and ensures
554 : * that there is a unique place that a clause can be moved down to.
555 : *
556 : * We cannot move an outer-join clause into the non-nullable side of its
557 : * outer join, as that would change the results (rows would be suppressed
558 : * rather than being null-extended).
559 : *
560 : * Also there must not be an outer join below the clause that would null the
561 : * Vars coming from the target relation. Otherwise the clause might give
562 : * results different from what it would give at its normal semantic level.
563 : *
564 : * Also, the join clause must not use any relations that have LATERAL
565 : * references to the target relation, since we could not put such rels on
566 : * the outer side of a nestloop with the target relation.
567 : *
568 : * Also, we reject is_clone versions of outer-join clauses. This has the
569 : * effect of preventing us from generating variant parameterized paths
570 : * that differ only in which outer joins null the parameterization rel(s).
571 : * Generating one path from the minimally-parameterized has_clone version
572 : * is sufficient.
573 : */
574 : bool
575 159139 : join_clause_is_movable_to(RestrictInfo *rinfo, RelOptInfo *baserel)
576 : {
577 : /* Clause must physically reference target rel */
578 159139 : if (!bms_is_member(baserel->relid, rinfo->clause_relids))
579 27957 : return false;
580 :
581 : /* Cannot move an outer-join clause into the join's outer side */
582 131182 : if (bms_is_member(baserel->relid, rinfo->outer_relids))
583 59560 : return false;
584 :
585 : /*
586 : * Target rel's Vars must not be nulled by any outer join. We can check
587 : * this without groveling through the individual Vars by seeing whether
588 : * clause_relids (which includes all such Vars' varnullingrels) includes
589 : * any outer join that can null the target rel. You might object that
590 : * this could reject the clause on the basis of an OJ relid that came from
591 : * some other rel's Var. However, that would still mean that the clause
592 : * came from above that outer join and shouldn't be pushed down; so there
593 : * should be no false positives.
594 : */
595 71622 : if (bms_overlap(rinfo->clause_relids, baserel->nulling_relids))
596 3775 : return false;
597 :
598 : /* Clause must not use any rels with LATERAL references to this rel */
599 67847 : if (bms_overlap(baserel->lateral_referencers, rinfo->clause_relids))
600 21 : return false;
601 :
602 : /* Ignore clones, too */
603 67826 : if (rinfo->is_clone)
604 4712 : return false;
605 :
606 63114 : return true;
607 : }
608 :
609 : /*
610 : * join_clause_is_movable_into
611 : * Test whether a join clause is movable and can be evaluated within
612 : * the current join context.
613 : *
614 : * currentrelids: the relids of the proposed evaluation location
615 : * current_and_outer: the union of currentrelids and the required_outer
616 : * relids (parameterization's outer relations)
617 : *
618 : * The API would be a bit clearer if we passed the current relids and the
619 : * outer relids separately and did bms_union internally; but since most
620 : * callers need to apply this function to multiple clauses, we make the
621 : * caller perform the union.
622 : *
623 : * Obviously, the clause must only refer to Vars available from the current
624 : * relation plus the outer rels. We also check that it does reference at
625 : * least one current Var, ensuring that the clause will be pushed down to
626 : * a unique place in a parameterized join tree. And we check that we're
627 : * not pushing the clause into its outer-join outer side.
628 : *
629 : * We used to need to check that we're not pushing the clause into a lower
630 : * outer join's inner side. However, now that clause_relids includes
631 : * references to potentially-nulling outer joins, the other tests handle that
632 : * concern. If the clause references any Var coming from the inside of a
633 : * lower outer join, its clause_relids will mention that outer join, causing
634 : * the evaluability check to fail; while if it references no such Vars, the
635 : * references-a-target-rel check will fail.
636 : *
637 : * There's no check here equivalent to join_clause_is_movable_to's test on
638 : * lateral_referencers. We assume the caller wouldn't be inquiring unless
639 : * it'd verified that the proposed outer rels don't have lateral references
640 : * to the current rel(s). (If we are considering join paths with the outer
641 : * rels on the outside and the current rels on the inside, then this should
642 : * have been checked at the outset of such consideration; see join_is_legal
643 : * and the path parameterization checks in joinpath.c.) On the other hand,
644 : * in join_clause_is_movable_to we are asking whether the clause could be
645 : * moved for some valid set of outer rels, so we don't have the benefit of
646 : * relying on prior checks for lateral-reference validity.
647 : *
648 : * Likewise, we don't check is_clone here: rejecting the inappropriate
649 : * variants of a cloned clause must be handled upstream.
650 : *
651 : * Note: if this returns true, it means that the clause could be moved to
652 : * this join relation, but that doesn't mean that this is the lowest join
653 : * it could be moved to. Caller may need to make additional calls to verify
654 : * that this doesn't succeed on either of the inputs of a proposed join.
655 : *
656 : * Note: get_joinrel_parampathinfo depends on the fact that if
657 : * current_and_outer is NULL, this function will always return false
658 : * (since one or the other of the first two tests must fail).
659 : */
660 : bool
661 209468 : join_clause_is_movable_into(RestrictInfo *rinfo,
662 : Relids currentrelids,
663 : Relids current_and_outer)
664 : {
665 : /* Clause must be evaluable given available context */
666 209468 : if (!bms_is_subset(rinfo->clause_relids, current_and_outer))
667 39606 : return false;
668 :
669 : /* Clause must physically reference at least one target rel */
670 169862 : if (!bms_overlap(currentrelids, rinfo->clause_relids))
671 12685 : return false;
672 :
673 : /* Cannot move an outer-join clause into the join's outer side */
674 157177 : if (bms_overlap(currentrelids, rinfo->outer_relids))
675 625 : return false;
676 :
677 156552 : return true;
678 : }
|
