Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * joinrels.c
4 : * Routines to determine which relations should be joined
5 : *
6 : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : *
10 : * IDENTIFICATION
11 : * src/backend/optimizer/path/joinrels.c
12 : *
13 : *-------------------------------------------------------------------------
14 : */
15 : #include "postgres.h"
16 :
17 : #include "miscadmin.h"
18 : #include "optimizer/appendinfo.h"
19 : #include "optimizer/joininfo.h"
20 : #include "optimizer/pathnode.h"
21 : #include "optimizer/paths.h"
22 : #include "optimizer/planner.h"
23 : #include "partitioning/partbounds.h"
24 : #include "utils/memutils.h"
25 :
26 :
27 : static void make_rels_by_clause_joins(PlannerInfo *root,
28 : RelOptInfo *old_rel,
29 : List *other_rels,
30 : int first_rel_idx);
31 : static void make_rels_by_clauseless_joins(PlannerInfo *root,
32 : RelOptInfo *old_rel,
33 : List *other_rels);
34 : static bool has_join_restriction(PlannerInfo *root, RelOptInfo *rel);
35 : static bool has_legal_joinclause(PlannerInfo *root, RelOptInfo *rel);
36 : static bool restriction_is_constant_false(List *restrictlist,
37 : RelOptInfo *joinrel,
38 : bool only_pushed_down);
39 : static void populate_joinrel_with_paths(PlannerInfo *root, RelOptInfo *rel1,
40 : RelOptInfo *rel2, RelOptInfo *joinrel,
41 : SpecialJoinInfo *sjinfo, List *restrictlist);
42 : static void try_partitionwise_join(PlannerInfo *root, RelOptInfo *rel1,
43 : RelOptInfo *rel2, RelOptInfo *joinrel,
44 : SpecialJoinInfo *parent_sjinfo,
45 : List *parent_restrictlist);
46 : static SpecialJoinInfo *build_child_join_sjinfo(PlannerInfo *root,
47 : SpecialJoinInfo *parent_sjinfo,
48 : Relids left_relids, Relids right_relids);
49 : static void free_child_join_sjinfo(SpecialJoinInfo *child_sjinfo,
50 : SpecialJoinInfo *parent_sjinfo);
51 : static void compute_partition_bounds(PlannerInfo *root, RelOptInfo *rel1,
52 : RelOptInfo *rel2, RelOptInfo *joinrel,
53 : SpecialJoinInfo *parent_sjinfo,
54 : List **parts1, List **parts2);
55 : static void get_matching_part_pairs(PlannerInfo *root, RelOptInfo *joinrel,
56 : RelOptInfo *rel1, RelOptInfo *rel2,
57 : List **parts1, List **parts2);
58 :
59 :
60 : /*
61 : * join_search_one_level
62 : * Consider ways to produce join relations containing exactly 'level'
63 : * jointree items. (This is one step of the dynamic-programming method
64 : * embodied in standard_join_search.) Join rel nodes for each feasible
65 : * combination of lower-level rels are created and returned in a list.
66 : * Implementation paths are created for each such joinrel, too.
67 : *
68 : * level: level of rels we want to make this time
69 : * root->join_rel_level[j], 1 <= j < level, is a list of rels containing j items
70 : *
71 : * The result is returned in root->join_rel_level[level].
72 : */
73 : void
74 129846 : join_search_one_level(PlannerInfo *root, int level)
75 : {
76 129846 : List **joinrels = root->join_rel_level;
77 : ListCell *r;
78 : int k;
79 :
80 : Assert(joinrels[level] == NIL);
81 :
82 : /* Set join_cur_level so that new joinrels are added to proper list */
83 129846 : root->join_cur_level = level;
84 :
85 : /*
86 : * First, consider left-sided and right-sided plans, in which rels of
87 : * exactly level-1 member relations are joined against initial relations.
88 : * We prefer to join using join clauses, but if we find a rel of level-1
89 : * members that has no join clauses, we will generate Cartesian-product
90 : * joins against all initial rels not already contained in it.
91 : */
92 457994 : foreach(r, joinrels[level - 1])
93 : {
94 328148 : RelOptInfo *old_rel = (RelOptInfo *) lfirst(r);
95 :
96 358430 : if (old_rel->joininfo != NIL || old_rel->has_eclass_joins ||
97 30282 : has_join_restriction(root, old_rel))
98 317504 : {
99 : int first_rel;
100 :
101 : /*
102 : * There are join clauses or join order restrictions relevant to
103 : * this rel, so consider joins between this rel and (only) those
104 : * initial rels it is linked to by a clause or restriction.
105 : *
106 : * At level 2 this condition is symmetric, so there is no need to
107 : * look at initial rels before this one in the list; we already
108 : * considered such joins when we were at the earlier rel. (The
109 : * mirror-image joins are handled automatically by make_join_rel.)
110 : * In later passes (level > 2), we join rels of the previous level
111 : * to each initial rel they don't already include but have a join
112 : * clause or restriction with.
113 : */
114 317504 : if (level == 2) /* consider remaining initial rels */
115 215180 : first_rel = foreach_current_index(r) + 1;
116 : else
117 102324 : first_rel = 0;
118 :
119 317504 : make_rels_by_clause_joins(root, old_rel, joinrels[1], first_rel);
120 : }
121 : else
122 : {
123 : /*
124 : * Oops, we have a relation that is not joined to any other
125 : * relation, either directly or by join-order restrictions.
126 : * Cartesian product time.
127 : *
128 : * We consider a cartesian product with each not-already-included
129 : * initial rel, whether it has other join clauses or not. At
130 : * level 2, if there are two or more clauseless initial rels, we
131 : * will redundantly consider joining them in both directions; but
132 : * such cases aren't common enough to justify adding complexity to
133 : * avoid the duplicated effort.
134 : */
135 10644 : make_rels_by_clauseless_joins(root,
136 : old_rel,
137 10644 : joinrels[1]);
138 : }
139 : }
140 :
141 : /*
142 : * Now, consider "bushy plans" in which relations of k initial rels are
143 : * joined to relations of level-k initial rels, for 2 <= k <= level-2.
144 : *
145 : * We only consider bushy-plan joins for pairs of rels where there is a
146 : * suitable join clause (or join order restriction), in order to avoid
147 : * unreasonable growth of planning time.
148 : */
149 129846 : for (k = 2;; k++)
150 12458 : {
151 142304 : int other_level = level - k;
152 :
153 : /*
154 : * Since make_join_rel(x, y) handles both x,y and y,x cases, we only
155 : * need to go as far as the halfway point.
156 : */
157 142304 : if (k > other_level)
158 129846 : break;
159 :
160 64564 : foreach(r, joinrels[k])
161 : {
162 52106 : RelOptInfo *old_rel = (RelOptInfo *) lfirst(r);
163 : int first_rel;
164 : ListCell *r2;
165 :
166 : /*
167 : * We can ignore relations without join clauses here, unless they
168 : * participate in join-order restrictions --- then we might have
169 : * to force a bushy join plan.
170 : */
171 52106 : if (old_rel->joininfo == NIL && !old_rel->has_eclass_joins &&
172 432 : !has_join_restriction(root, old_rel))
173 300 : continue;
174 :
175 51806 : if (k == other_level) /* only consider remaining rels */
176 35766 : first_rel = foreach_current_index(r) + 1;
177 : else
178 16040 : first_rel = 0;
179 :
180 226958 : for_each_from(r2, joinrels[other_level], first_rel)
181 : {
182 175152 : RelOptInfo *new_rel = (RelOptInfo *) lfirst(r2);
183 :
184 175152 : if (!bms_overlap(old_rel->relids, new_rel->relids))
185 : {
186 : /*
187 : * OK, we can build a rel of the right level from this
188 : * pair of rels. Do so if there is at least one relevant
189 : * join clause or join order restriction.
190 : */
191 21544 : if (have_relevant_joinclause(root, old_rel, new_rel) ||
192 1154 : have_join_order_restriction(root, old_rel, new_rel))
193 : {
194 19302 : (void) make_join_rel(root, old_rel, new_rel);
195 : }
196 : }
197 : }
198 : }
199 : }
200 :
201 : /*----------
202 : * Last-ditch effort: if we failed to find any usable joins so far, force
203 : * a set of cartesian-product joins to be generated. This handles the
204 : * special case where all the available rels have join clauses but we
205 : * cannot use any of those clauses yet. This can only happen when we are
206 : * considering a join sub-problem (a sub-joinlist) and all the rels in the
207 : * sub-problem have only join clauses with rels outside the sub-problem.
208 : * An example is
209 : *
210 : * SELECT ... FROM a INNER JOIN b ON TRUE, c, d, ...
211 : * WHERE a.w = c.x and b.y = d.z;
212 : *
213 : * If the "a INNER JOIN b" sub-problem does not get flattened into the
214 : * upper level, we must be willing to make a cartesian join of a and b;
215 : * but the code above will not have done so, because it thought that both
216 : * a and b have joinclauses. We consider only left-sided and right-sided
217 : * cartesian joins in this case (no bushy).
218 : *----------
219 : */
220 129846 : if (joinrels[level] == NIL)
221 : {
222 : /*
223 : * This loop is just like the first one, except we always call
224 : * make_rels_by_clauseless_joins().
225 : */
226 54 : foreach(r, joinrels[level - 1])
227 : {
228 36 : RelOptInfo *old_rel = (RelOptInfo *) lfirst(r);
229 :
230 36 : make_rels_by_clauseless_joins(root,
231 : old_rel,
232 36 : joinrels[1]);
233 : }
234 :
235 : /*----------
236 : * When special joins are involved, there may be no legal way
237 : * to make an N-way join for some values of N. For example consider
238 : *
239 : * SELECT ... FROM t1 WHERE
240 : * x IN (SELECT ... FROM t2,t3 WHERE ...) AND
241 : * y IN (SELECT ... FROM t4,t5 WHERE ...)
242 : *
243 : * We will flatten this query to a 5-way join problem, but there are
244 : * no 4-way joins that join_is_legal() will consider legal. We have
245 : * to accept failure at level 4 and go on to discover a workable
246 : * bushy plan at level 5.
247 : *
248 : * However, if there are no special joins and no lateral references
249 : * then join_is_legal() should never fail, and so the following sanity
250 : * check is useful.
251 : *----------
252 : */
253 18 : if (joinrels[level] == NIL &&
254 6 : root->join_info_list == NIL &&
255 0 : !root->hasLateralRTEs)
256 0 : elog(ERROR, "failed to build any %d-way joins", level);
257 : }
258 129846 : }
259 :
260 : /*
261 : * make_rels_by_clause_joins
262 : * Build joins between the given relation 'old_rel' and other relations
263 : * that participate in join clauses that 'old_rel' also participates in
264 : * (or participate in join-order restrictions with it).
265 : * The join rels are returned in root->join_rel_level[join_cur_level].
266 : *
267 : * Note: at levels above 2 we will generate the same joined relation in
268 : * multiple ways --- for example (a join b) join c is the same RelOptInfo as
269 : * (b join c) join a, though the second case will add a different set of Paths
270 : * to it. This is the reason for using the join_rel_level mechanism, which
271 : * automatically ensures that each new joinrel is only added to the list once.
272 : *
273 : * 'old_rel' is the relation entry for the relation to be joined
274 : * 'other_rels': a list containing the other rels to be considered for joining
275 : * 'first_rel_idx': the first rel to be considered in 'other_rels'
276 : *
277 : * Currently, this is only used with initial rels in other_rels, but it
278 : * will work for joining to joinrels too.
279 : */
280 : static void
281 317504 : make_rels_by_clause_joins(PlannerInfo *root,
282 : RelOptInfo *old_rel,
283 : List *other_rels,
284 : int first_rel_idx)
285 : {
286 : ListCell *l;
287 :
288 928200 : for_each_from(l, other_rels, first_rel_idx)
289 : {
290 610696 : RelOptInfo *other_rel = (RelOptInfo *) lfirst(l);
291 :
292 958870 : if (!bms_overlap(old_rel->relids, other_rel->relids) &&
293 421768 : (have_relevant_joinclause(root, old_rel, other_rel) ||
294 73594 : have_join_order_restriction(root, old_rel, other_rel)))
295 : {
296 286240 : (void) make_join_rel(root, old_rel, other_rel);
297 : }
298 : }
299 317504 : }
300 :
301 : /*
302 : * make_rels_by_clauseless_joins
303 : * Given a relation 'old_rel' and a list of other relations
304 : * 'other_rels', create a join relation between 'old_rel' and each
305 : * member of 'other_rels' that isn't already included in 'old_rel'.
306 : * The join rels are returned in root->join_rel_level[join_cur_level].
307 : *
308 : * 'old_rel' is the relation entry for the relation to be joined
309 : * 'other_rels': a list containing the other rels to be considered for joining
310 : *
311 : * Currently, this is only used with initial rels in other_rels, but it would
312 : * work for joining to joinrels too.
313 : */
314 : static void
315 10680 : make_rels_by_clauseless_joins(PlannerInfo *root,
316 : RelOptInfo *old_rel,
317 : List *other_rels)
318 : {
319 : ListCell *l;
320 :
321 34158 : foreach(l, other_rels)
322 : {
323 23478 : RelOptInfo *other_rel = (RelOptInfo *) lfirst(l);
324 :
325 23478 : if (!bms_overlap(other_rel->relids, old_rel->relids))
326 : {
327 11582 : (void) make_join_rel(root, old_rel, other_rel);
328 : }
329 : }
330 10680 : }
331 :
332 :
333 : /*
334 : * join_is_legal
335 : * Determine whether a proposed join is legal given the query's
336 : * join order constraints; and if it is, determine the join type.
337 : *
338 : * Caller must supply not only the two rels, but the union of their relids.
339 : * (We could simplify the API by computing joinrelids locally, but this
340 : * would be redundant work in the normal path through make_join_rel.
341 : * Note that this value does NOT include the RT index of any outer join that
342 : * might need to be performed here, so it's not the canonical identifier
343 : * of the join relation.)
344 : *
345 : * On success, *sjinfo_p is set to NULL if this is to be a plain inner join,
346 : * else it's set to point to the associated SpecialJoinInfo node. Also,
347 : * *reversed_p is set true if the given relations need to be swapped to
348 : * match the SpecialJoinInfo node.
349 : */
350 : static bool
351 322284 : join_is_legal(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2,
352 : Relids joinrelids,
353 : SpecialJoinInfo **sjinfo_p, bool *reversed_p)
354 : {
355 : SpecialJoinInfo *match_sjinfo;
356 : bool reversed;
357 : bool unique_ified;
358 : bool must_be_leftjoin;
359 : ListCell *l;
360 :
361 : /*
362 : * Ensure output params are set on failure return. This is just to
363 : * suppress uninitialized-variable warnings from overly anal compilers.
364 : */
365 322284 : *sjinfo_p = NULL;
366 322284 : *reversed_p = false;
367 :
368 : /*
369 : * If we have any special joins, the proposed join might be illegal; and
370 : * in any case we have to determine its join type. Scan the join info
371 : * list for matches and conflicts.
372 : */
373 322284 : match_sjinfo = NULL;
374 322284 : reversed = false;
375 322284 : unique_ified = false;
376 322284 : must_be_leftjoin = false;
377 :
378 674156 : foreach(l, root->join_info_list)
379 : {
380 361124 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
381 :
382 : /*
383 : * This special join is not relevant unless its RHS overlaps the
384 : * proposed join. (Check this first as a fast path for dismissing
385 : * most irrelevant SJs quickly.)
386 : */
387 361124 : if (!bms_overlap(sjinfo->min_righthand, joinrelids))
388 120602 : continue;
389 :
390 : /*
391 : * Also, not relevant if proposed join is fully contained within RHS
392 : * (ie, we're still building up the RHS).
393 : */
394 240522 : if (bms_is_subset(joinrelids, sjinfo->min_righthand))
395 5272 : continue;
396 :
397 : /*
398 : * Also, not relevant if SJ is already done within either input.
399 : */
400 439010 : if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) &&
401 203760 : bms_is_subset(sjinfo->min_righthand, rel1->relids))
402 99432 : continue;
403 156382 : if (bms_is_subset(sjinfo->min_lefthand, rel2->relids) &&
404 20564 : bms_is_subset(sjinfo->min_righthand, rel2->relids))
405 10754 : continue;
406 :
407 : /*
408 : * If it's a semijoin and we already joined the RHS to any other rels
409 : * within either input, then we must have unique-ified the RHS at that
410 : * point (see below). Therefore the semijoin is no longer relevant in
411 : * this join path.
412 : */
413 125064 : if (sjinfo->jointype == JOIN_SEMI)
414 : {
415 10984 : if (bms_is_subset(sjinfo->syn_righthand, rel1->relids) &&
416 1606 : !bms_equal(sjinfo->syn_righthand, rel1->relids))
417 666 : continue;
418 10318 : if (bms_is_subset(sjinfo->syn_righthand, rel2->relids) &&
419 7230 : !bms_equal(sjinfo->syn_righthand, rel2->relids))
420 214 : continue;
421 : }
422 :
423 : /*
424 : * If one input contains min_lefthand and the other contains
425 : * min_righthand, then we can perform the SJ at this join.
426 : *
427 : * Reject if we get matches to more than one SJ; that implies we're
428 : * considering something that's not really valid.
429 : */
430 228360 : if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) &&
431 104176 : bms_is_subset(sjinfo->min_righthand, rel2->relids))
432 : {
433 97548 : if (match_sjinfo)
434 9252 : return false; /* invalid join path */
435 97548 : match_sjinfo = sjinfo;
436 97548 : reversed = false;
437 : }
438 36108 : else if (bms_is_subset(sjinfo->min_lefthand, rel2->relids) &&
439 9472 : bms_is_subset(sjinfo->min_righthand, rel1->relids))
440 : {
441 8248 : if (match_sjinfo)
442 0 : return false; /* invalid join path */
443 8248 : match_sjinfo = sjinfo;
444 8248 : reversed = true;
445 : }
446 21464 : else if (sjinfo->jointype == JOIN_SEMI &&
447 3714 : bms_equal(sjinfo->syn_righthand, rel2->relids) &&
448 638 : create_unique_paths(root, rel2, sjinfo) != NULL)
449 : {
450 : /*----------
451 : * For a semijoin, we can join the RHS to anything else by
452 : * unique-ifying the RHS (if the RHS can be unique-ified).
453 : * We will only get here if we have the full RHS but less
454 : * than min_lefthand on the LHS.
455 : *
456 : * The reason to consider such a join path is exemplified by
457 : * SELECT ... FROM a,b WHERE (a.x,b.y) IN (SELECT c1,c2 FROM c)
458 : * If we insist on doing this as a semijoin we will first have
459 : * to form the cartesian product of A*B. But if we unique-ify
460 : * C then the semijoin becomes a plain innerjoin and we can join
461 : * in any order, eg C to A and then to B. When C is much smaller
462 : * than A and B this can be a huge win. So we allow C to be
463 : * joined to just A or just B here, and then make_join_rel has
464 : * to handle the case properly.
465 : *
466 : * Note that actually we'll allow unique-ified C to be joined to
467 : * some other relation D here, too. That is legal, if usually not
468 : * very sane, and this routine is only concerned with legality not
469 : * with whether the join is good strategy.
470 : *----------
471 : */
472 632 : if (match_sjinfo)
473 84 : return false; /* invalid join path */
474 548 : match_sjinfo = sjinfo;
475 548 : reversed = false;
476 548 : unique_ified = true;
477 : }
478 20200 : else if (sjinfo->jointype == JOIN_SEMI &&
479 2734 : bms_equal(sjinfo->syn_righthand, rel1->relids) &&
480 290 : create_unique_paths(root, rel1, sjinfo) != NULL)
481 : {
482 : /* Reversed semijoin case */
483 290 : if (match_sjinfo)
484 78 : return false; /* invalid join path */
485 212 : match_sjinfo = sjinfo;
486 212 : reversed = true;
487 212 : unique_ified = true;
488 : }
489 : else
490 : {
491 : /*
492 : * Otherwise, the proposed join overlaps the RHS but isn't a valid
493 : * implementation of this SJ. But don't panic quite yet: the RHS
494 : * violation might have occurred previously, in one or both input
495 : * relations, in which case we must have previously decided that
496 : * it was OK to commute some other SJ with this one. If we need
497 : * to perform this join to finish building up the RHS, rejecting
498 : * it could lead to not finding any plan at all. (This can occur
499 : * because of the heuristics elsewhere in this file that postpone
500 : * clauseless joins: we might not consider doing a clauseless join
501 : * within the RHS until after we've performed other, validly
502 : * commutable SJs with one or both sides of the clauseless join.)
503 : * This consideration boils down to the rule that if both inputs
504 : * overlap the RHS, we can allow the join --- they are either
505 : * fully within the RHS, or represent previously-allowed joins to
506 : * rels outside it.
507 : */
508 25654 : if (bms_overlap(rel1->relids, sjinfo->min_righthand) &&
509 8188 : bms_overlap(rel2->relids, sjinfo->min_righthand))
510 174 : continue; /* assume valid previous violation of RHS */
511 :
512 : /*
513 : * The proposed join could still be legal, but only if we're
514 : * allowed to associate it into the RHS of this SJ. That means
515 : * this SJ must be a LEFT join (not SEMI or ANTI, and certainly
516 : * not FULL) and the proposed join must not overlap the LHS.
517 : */
518 32298 : if (sjinfo->jointype != JOIN_LEFT ||
519 15006 : bms_overlap(joinrelids, sjinfo->min_lefthand))
520 9090 : return false; /* invalid join path */
521 :
522 : /*
523 : * To be valid, the proposed join must be a LEFT join; otherwise
524 : * it can't associate into this SJ's RHS. But we may not yet have
525 : * found the SpecialJoinInfo matching the proposed join, so we
526 : * can't test that yet. Remember the requirement for later.
527 : */
528 8202 : must_be_leftjoin = true;
529 : }
530 : }
531 :
532 : /*
533 : * Fail if violated any SJ's RHS and didn't match to a LEFT SJ: the
534 : * proposed join can't associate into an SJ's RHS.
535 : *
536 : * Also, fail if the proposed join's predicate isn't strict; we're
537 : * essentially checking to see if we can apply outer-join identity 3, and
538 : * that's a requirement. (This check may be redundant with checks in
539 : * make_outerjoininfo, but I'm not quite sure, and it's cheap to test.)
540 : */
541 313032 : if (must_be_leftjoin &&
542 5230 : (match_sjinfo == NULL ||
543 5230 : match_sjinfo->jointype != JOIN_LEFT ||
544 5230 : !match_sjinfo->lhs_strict))
545 1498 : return false; /* invalid join path */
546 :
547 : /*
548 : * We also have to check for constraints imposed by LATERAL references.
549 : */
550 311534 : if (root->hasLateralRTEs)
551 : {
552 : bool lateral_fwd;
553 : bool lateral_rev;
554 : Relids join_lateral_rels;
555 :
556 : /*
557 : * The proposed rels could each contain lateral references to the
558 : * other, in which case the join is impossible. If there are lateral
559 : * references in just one direction, then the join has to be done with
560 : * a nestloop with the lateral referencer on the inside. If the join
561 : * matches an SJ that cannot be implemented by such a nestloop, the
562 : * join is impossible.
563 : *
564 : * Also, if the lateral reference is only indirect, we should reject
565 : * the join; whatever rel(s) the reference chain goes through must be
566 : * joined to first.
567 : */
568 17582 : lateral_fwd = bms_overlap(rel1->relids, rel2->lateral_relids);
569 17582 : lateral_rev = bms_overlap(rel2->relids, rel1->lateral_relids);
570 17582 : if (lateral_fwd && lateral_rev)
571 30 : return false; /* have lateral refs in both directions */
572 17552 : if (lateral_fwd)
573 : {
574 : /* has to be implemented as nestloop with rel1 on left */
575 10212 : if (match_sjinfo &&
576 426 : (reversed ||
577 408 : unique_ified ||
578 408 : match_sjinfo->jointype == JOIN_FULL))
579 18 : return false; /* not implementable as nestloop */
580 : /* check there is a direct reference from rel2 to rel1 */
581 10194 : if (!bms_overlap(rel1->relids, rel2->direct_lateral_relids))
582 42 : return false; /* only indirect refs, so reject */
583 : }
584 7340 : else if (lateral_rev)
585 : {
586 : /* has to be implemented as nestloop with rel2 on left */
587 1650 : if (match_sjinfo &&
588 78 : (!reversed ||
589 78 : unique_ified ||
590 78 : match_sjinfo->jointype == JOIN_FULL))
591 0 : return false; /* not implementable as nestloop */
592 : /* check there is a direct reference from rel1 to rel2 */
593 1650 : if (!bms_overlap(rel2->relids, rel1->direct_lateral_relids))
594 0 : return false; /* only indirect refs, so reject */
595 : }
596 :
597 : /*
598 : * LATERAL references could also cause problems later on if we accept
599 : * this join: if the join's minimum parameterization includes any rels
600 : * that would have to be on the inside of an outer join with this join
601 : * rel, then it's never going to be possible to build the complete
602 : * query using this join. We should reject this join not only because
603 : * it'll save work, but because if we don't, the clauseless-join
604 : * heuristics might think that legality of this join means that some
605 : * other join rel need not be formed, and that could lead to failure
606 : * to find any plan at all. We have to consider not only rels that
607 : * are directly on the inner side of an OJ with the joinrel, but also
608 : * ones that are indirectly so, so search to find all such rels.
609 : */
610 17492 : join_lateral_rels = min_join_parameterization(root, joinrelids,
611 : rel1, rel2);
612 17492 : if (join_lateral_rels)
613 : {
614 2372 : Relids join_plus_rhs = bms_copy(joinrelids);
615 : bool more;
616 :
617 : do
618 : {
619 2768 : more = false;
620 4694 : foreach(l, root->join_info_list)
621 : {
622 1926 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
623 :
624 : /* ignore full joins --- their ordering is predetermined */
625 1926 : if (sjinfo->jointype == JOIN_FULL)
626 18 : continue;
627 :
628 1908 : if (bms_overlap(sjinfo->min_lefthand, join_plus_rhs) &&
629 1602 : !bms_is_subset(sjinfo->min_righthand, join_plus_rhs))
630 : {
631 546 : join_plus_rhs = bms_add_members(join_plus_rhs,
632 546 : sjinfo->min_righthand);
633 546 : more = true;
634 : }
635 : }
636 2768 : } while (more);
637 2372 : if (bms_overlap(join_plus_rhs, join_lateral_rels))
638 312 : return false; /* will not be able to join to some RHS rel */
639 : }
640 : }
641 :
642 : /* Otherwise, it's a valid join */
643 311132 : *sjinfo_p = match_sjinfo;
644 311132 : *reversed_p = reversed;
645 311132 : return true;
646 : }
647 :
648 : /*
649 : * init_dummy_sjinfo
650 : * Populate the given SpecialJoinInfo for a plain inner join between the
651 : * left and right relations specified by left_relids and right_relids
652 : * respectively.
653 : *
654 : * Normally, an inner join does not have a SpecialJoinInfo node associated with
655 : * it. But some functions involved in join planning require one containing at
656 : * least the information of which relations are being joined. So we initialize
657 : * that information here.
658 : */
659 : void
660 878934 : init_dummy_sjinfo(SpecialJoinInfo *sjinfo, Relids left_relids,
661 : Relids right_relids)
662 : {
663 878934 : sjinfo->type = T_SpecialJoinInfo;
664 878934 : sjinfo->min_lefthand = left_relids;
665 878934 : sjinfo->min_righthand = right_relids;
666 878934 : sjinfo->syn_lefthand = left_relids;
667 878934 : sjinfo->syn_righthand = right_relids;
668 878934 : sjinfo->jointype = JOIN_INNER;
669 878934 : sjinfo->ojrelid = 0;
670 878934 : sjinfo->commute_above_l = NULL;
671 878934 : sjinfo->commute_above_r = NULL;
672 878934 : sjinfo->commute_below_l = NULL;
673 878934 : sjinfo->commute_below_r = NULL;
674 : /* we don't bother trying to make the remaining fields valid */
675 878934 : sjinfo->lhs_strict = false;
676 878934 : sjinfo->semi_can_btree = false;
677 878934 : sjinfo->semi_can_hash = false;
678 878934 : sjinfo->semi_operators = NIL;
679 878934 : sjinfo->semi_rhs_exprs = NIL;
680 878934 : }
681 :
682 : /*
683 : * make_join_rel
684 : * Find or create a join RelOptInfo that represents the join of
685 : * the two given rels, and add to it path information for paths
686 : * created with the two rels as outer and inner rel.
687 : * (The join rel may already contain paths generated from other
688 : * pairs of rels that add up to the same set of base rels.)
689 : *
690 : * NB: will return NULL if attempted join is not valid. This can happen
691 : * when working with outer joins, or with IN or EXISTS clauses that have been
692 : * turned into joins.
693 : */
694 : RelOptInfo *
695 321876 : make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
696 : {
697 : Relids joinrelids;
698 : SpecialJoinInfo *sjinfo;
699 : bool reversed;
700 321876 : List *pushed_down_joins = NIL;
701 : SpecialJoinInfo sjinfo_data;
702 : RelOptInfo *joinrel;
703 : List *restrictlist;
704 :
705 : /* We should never try to join two overlapping sets of rels. */
706 : Assert(!bms_overlap(rel1->relids, rel2->relids));
707 :
708 : /* Construct Relids set that identifies the joinrel (without OJ as yet). */
709 321876 : joinrelids = bms_union(rel1->relids, rel2->relids);
710 :
711 : /* Check validity and determine join type. */
712 321876 : if (!join_is_legal(root, rel1, rel2, joinrelids,
713 : &sjinfo, &reversed))
714 : {
715 : /* invalid join path */
716 10996 : bms_free(joinrelids);
717 10996 : return NULL;
718 : }
719 :
720 : /*
721 : * Add outer join relid(s) to form the canonical relids. Any added outer
722 : * joins besides sjinfo itself are appended to pushed_down_joins.
723 : */
724 310880 : joinrelids = add_outer_joins_to_relids(root, joinrelids, sjinfo,
725 : &pushed_down_joins);
726 :
727 : /* Swap rels if needed to match the join info. */
728 310880 : if (reversed)
729 : {
730 8304 : RelOptInfo *trel = rel1;
731 :
732 8304 : rel1 = rel2;
733 8304 : rel2 = trel;
734 : }
735 :
736 : /*
737 : * If it's a plain inner join, then we won't have found anything in
738 : * join_info_list. Make up a SpecialJoinInfo so that selectivity
739 : * estimation functions will know what's being joined.
740 : */
741 310880 : if (sjinfo == NULL)
742 : {
743 204912 : sjinfo = &sjinfo_data;
744 204912 : init_dummy_sjinfo(sjinfo, rel1->relids, rel2->relids);
745 : }
746 :
747 : /*
748 : * Find or build the join RelOptInfo, and compute the restrictlist that
749 : * goes with this particular joining.
750 : */
751 310880 : joinrel = build_join_rel(root, joinrelids, rel1, rel2,
752 : sjinfo, pushed_down_joins,
753 : &restrictlist);
754 :
755 : /*
756 : * If we've already proven this join is empty, we needn't consider any
757 : * more paths for it.
758 : */
759 310880 : if (is_dummy_rel(joinrel))
760 : {
761 492 : bms_free(joinrelids);
762 492 : return joinrel;
763 : }
764 :
765 : /* Add paths to the join relation. */
766 310388 : populate_joinrel_with_paths(root, rel1, rel2, joinrel, sjinfo,
767 : restrictlist);
768 :
769 310388 : bms_free(joinrelids);
770 :
771 310388 : return joinrel;
772 : }
773 :
774 : /*
775 : * add_outer_joins_to_relids
776 : * Add relids to input_relids to represent any outer joins that will be
777 : * calculated at this join.
778 : *
779 : * input_relids is the union of the relid sets of the two input relations.
780 : * Note that we modify this in-place and return it; caller must bms_copy()
781 : * it first, if a separate value is desired.
782 : *
783 : * sjinfo represents the join being performed.
784 : *
785 : * If the current join completes the calculation of any outer joins that
786 : * have been pushed down per outer-join identity 3, those relids will be
787 : * added to the result along with sjinfo's own relid. If pushed_down_joins
788 : * is not NULL, then also the SpecialJoinInfos for such added outer joins will
789 : * be appended to *pushed_down_joins (so caller must initialize it to NIL).
790 : */
791 : Relids
792 318398 : add_outer_joins_to_relids(PlannerInfo *root, Relids input_relids,
793 : SpecialJoinInfo *sjinfo,
794 : List **pushed_down_joins)
795 : {
796 : /* Nothing to do if this isn't an outer join with an assigned relid. */
797 318398 : if (sjinfo == NULL || sjinfo->ojrelid == 0)
798 223478 : return input_relids;
799 :
800 : /*
801 : * If it's not a left join, we have no rules that would permit executing
802 : * it in non-syntactic order, so just form the syntactic relid set. (This
803 : * is just a quick-exit test; we'd come to the same conclusion anyway,
804 : * since its commute_below_l and commute_above_l sets must be empty.)
805 : */
806 94920 : if (sjinfo->jointype != JOIN_LEFT)
807 2236 : return bms_add_member(input_relids, sjinfo->ojrelid);
808 :
809 : /*
810 : * We cannot add the OJ relid if this join has been pushed into the RHS of
811 : * a syntactically-lower left join per OJ identity 3. (If it has, then we
812 : * cannot claim that its outputs represent the final state of its RHS.)
813 : * There will not be any other OJs that can be added either, so we're
814 : * done.
815 : */
816 92684 : if (!bms_is_subset(sjinfo->commute_below_l, input_relids))
817 4930 : return input_relids;
818 :
819 : /* OK to add OJ's own relid */
820 87754 : input_relids = bms_add_member(input_relids, sjinfo->ojrelid);
821 :
822 : /*
823 : * Contrariwise, if we are now forming the final result of such a commuted
824 : * pair of OJs, it's time to add the relid(s) of the pushed-down join(s).
825 : * We can skip this if this join was never a candidate to be pushed up.
826 : */
827 87754 : if (sjinfo->commute_above_l)
828 : {
829 17556 : Relids commute_above_rels = bms_copy(sjinfo->commute_above_l);
830 : ListCell *lc;
831 :
832 : /*
833 : * The current join could complete the nulling of more than one
834 : * pushed-down join, so we have to examine all the SpecialJoinInfos.
835 : * Because join_info_list was built in bottom-up order, it's
836 : * sufficient to traverse it once: an ojrelid we add in one loop
837 : * iteration would not have affected decisions of earlier iterations.
838 : */
839 58932 : foreach(lc, root->join_info_list)
840 : {
841 41376 : SpecialJoinInfo *othersj = (SpecialJoinInfo *) lfirst(lc);
842 :
843 41376 : if (othersj == sjinfo ||
844 23820 : othersj->ojrelid == 0 || othersj->jointype != JOIN_LEFT)
845 17568 : continue; /* definitely not interesting */
846 :
847 23808 : if (!bms_is_member(othersj->ojrelid, commute_above_rels))
848 6104 : continue;
849 :
850 : /* Add it if not already present but conditions now satisfied */
851 35408 : if (!bms_is_member(othersj->ojrelid, input_relids) &&
852 35384 : bms_is_subset(othersj->min_lefthand, input_relids) &&
853 26608 : bms_is_subset(othersj->min_righthand, input_relids) &&
854 8928 : bms_is_subset(othersj->commute_below_l, input_relids))
855 : {
856 8892 : input_relids = bms_add_member(input_relids, othersj->ojrelid);
857 : /* report such pushed down outer joins, if asked */
858 8892 : if (pushed_down_joins != NULL)
859 8892 : *pushed_down_joins = lappend(*pushed_down_joins, othersj);
860 :
861 : /*
862 : * We must also check any joins that othersj potentially
863 : * commutes with. They likewise must appear later in
864 : * join_info_list than othersj itself, so we can visit them
865 : * later in this loop.
866 : */
867 8892 : commute_above_rels = bms_add_members(commute_above_rels,
868 8892 : othersj->commute_above_l);
869 : }
870 : }
871 : }
872 :
873 87754 : return input_relids;
874 : }
875 :
876 : /*
877 : * populate_joinrel_with_paths
878 : * Add paths to the given joinrel for given pair of joining relations. The
879 : * SpecialJoinInfo provides details about the join and the restrictlist
880 : * contains the join clauses and the other clauses applicable for given pair
881 : * of the joining relations.
882 : */
883 : static void
884 315934 : populate_joinrel_with_paths(PlannerInfo *root, RelOptInfo *rel1,
885 : RelOptInfo *rel2, RelOptInfo *joinrel,
886 : SpecialJoinInfo *sjinfo, List *restrictlist)
887 : {
888 : RelOptInfo *unique_rel2;
889 :
890 : /*
891 : * Consider paths using each rel as both outer and inner. Depending on
892 : * the join type, a provably empty outer or inner rel might mean the join
893 : * is provably empty too; in which case throw away any previously computed
894 : * paths and mark the join as dummy. (We do it this way since it's
895 : * conceivable that dummy-ness of a multi-element join might only be
896 : * noticeable for certain construction paths.)
897 : *
898 : * Also, a provably constant-false join restriction typically means that
899 : * we can skip evaluating one or both sides of the join. We do this by
900 : * marking the appropriate rel as dummy. For outer joins, a
901 : * constant-false restriction that is pushed down still means the whole
902 : * join is dummy, while a non-pushed-down one means that no inner rows
903 : * will join so we can treat the inner rel as dummy.
904 : *
905 : * We need only consider the jointypes that appear in join_info_list, plus
906 : * JOIN_INNER.
907 : */
908 315934 : switch (sjinfo->jointype)
909 : {
910 206822 : case JOIN_INNER:
911 413626 : if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
912 206804 : restriction_is_constant_false(restrictlist, joinrel, false))
913 : {
914 204 : mark_dummy_rel(joinrel);
915 204 : break;
916 : }
917 206618 : add_paths_to_joinrel(root, joinrel, rel1, rel2,
918 : JOIN_INNER, sjinfo,
919 : restrictlist);
920 206618 : add_paths_to_joinrel(root, joinrel, rel2, rel1,
921 : JOIN_INNER, sjinfo,
922 : restrictlist);
923 206618 : break;
924 94362 : case JOIN_LEFT:
925 188670 : if (is_dummy_rel(rel1) ||
926 94308 : restriction_is_constant_false(restrictlist, joinrel, true))
927 : {
928 86 : mark_dummy_rel(joinrel);
929 86 : break;
930 : }
931 94480 : if (restriction_is_constant_false(restrictlist, joinrel, false) &&
932 204 : bms_is_subset(rel2->relids, sjinfo->syn_righthand))
933 180 : mark_dummy_rel(rel2);
934 94276 : add_paths_to_joinrel(root, joinrel, rel1, rel2,
935 : JOIN_LEFT, sjinfo,
936 : restrictlist);
937 94276 : add_paths_to_joinrel(root, joinrel, rel2, rel1,
938 : JOIN_RIGHT, sjinfo,
939 : restrictlist);
940 94276 : break;
941 1732 : case JOIN_FULL:
942 3464 : if ((is_dummy_rel(rel1) && is_dummy_rel(rel2)) ||
943 1732 : restriction_is_constant_false(restrictlist, joinrel, true))
944 : {
945 12 : mark_dummy_rel(joinrel);
946 12 : break;
947 : }
948 1720 : add_paths_to_joinrel(root, joinrel, rel1, rel2,
949 : JOIN_FULL, sjinfo,
950 : restrictlist);
951 1720 : add_paths_to_joinrel(root, joinrel, rel2, rel1,
952 : JOIN_FULL, sjinfo,
953 : restrictlist);
954 :
955 : /*
956 : * If there are join quals that aren't mergeable or hashable, we
957 : * may not be able to build any valid plan. Complain here so that
958 : * we can give a somewhat-useful error message. (Since we have no
959 : * flexibility of planning for a full join, there's no chance of
960 : * succeeding later with another pair of input rels.)
961 : */
962 1720 : if (joinrel->pathlist == NIL)
963 0 : ereport(ERROR,
964 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
965 : errmsg("FULL JOIN is only supported with merge-joinable or hash-joinable join conditions")));
966 1720 : break;
967 7884 : case JOIN_SEMI:
968 :
969 : /*
970 : * We might have a normal semijoin, or a case where we don't have
971 : * enough rels to do the semijoin but can unique-ify the RHS and
972 : * then do an innerjoin (see comments in join_is_legal). In the
973 : * latter case we can't apply JOIN_SEMI joining.
974 : */
975 15362 : if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) &&
976 7478 : bms_is_subset(sjinfo->min_righthand, rel2->relids))
977 : {
978 14950 : if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
979 7472 : restriction_is_constant_false(restrictlist, joinrel, false))
980 : {
981 12 : mark_dummy_rel(joinrel);
982 12 : break;
983 : }
984 7466 : add_paths_to_joinrel(root, joinrel, rel1, rel2,
985 : JOIN_SEMI, sjinfo,
986 : restrictlist);
987 7466 : add_paths_to_joinrel(root, joinrel, rel2, rel1,
988 : JOIN_RIGHT_SEMI, sjinfo,
989 : restrictlist);
990 : }
991 :
992 : /*
993 : * If we know how to unique-ify the RHS and one input rel is
994 : * exactly the RHS (not a superset) we can consider unique-ifying
995 : * it and then doing a regular join. (The create_unique_paths
996 : * check here is probably redundant with what join_is_legal did,
997 : * but if so the check is cheap because it's cached. So test
998 : * anyway to be sure.)
999 : */
1000 15744 : if (bms_equal(sjinfo->syn_righthand, rel2->relids) &&
1001 7872 : (unique_rel2 = create_unique_paths(root, rel2, sjinfo)) != NULL)
1002 : {
1003 15492 : if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
1004 7746 : restriction_is_constant_false(restrictlist, joinrel, false))
1005 : {
1006 0 : mark_dummy_rel(joinrel);
1007 0 : break;
1008 : }
1009 7746 : add_paths_to_joinrel(root, joinrel, rel1, unique_rel2,
1010 : JOIN_UNIQUE_INNER, sjinfo,
1011 : restrictlist);
1012 7746 : add_paths_to_joinrel(root, joinrel, unique_rel2, rel1,
1013 : JOIN_UNIQUE_OUTER, sjinfo,
1014 : restrictlist);
1015 : }
1016 7872 : break;
1017 5134 : case JOIN_ANTI:
1018 10268 : if (is_dummy_rel(rel1) ||
1019 5134 : restriction_is_constant_false(restrictlist, joinrel, true))
1020 : {
1021 0 : mark_dummy_rel(joinrel);
1022 0 : break;
1023 : }
1024 5134 : if (restriction_is_constant_false(restrictlist, joinrel, false) &&
1025 0 : bms_is_subset(rel2->relids, sjinfo->syn_righthand))
1026 0 : mark_dummy_rel(rel2);
1027 5134 : add_paths_to_joinrel(root, joinrel, rel1, rel2,
1028 : JOIN_ANTI, sjinfo,
1029 : restrictlist);
1030 5134 : add_paths_to_joinrel(root, joinrel, rel2, rel1,
1031 : JOIN_RIGHT_ANTI, sjinfo,
1032 : restrictlist);
1033 5134 : break;
1034 0 : default:
1035 : /* other values not expected here */
1036 0 : elog(ERROR, "unrecognized join type: %d", (int) sjinfo->jointype);
1037 : break;
1038 : }
1039 :
1040 : /* Apply partitionwise join technique, if possible. */
1041 315934 : try_partitionwise_join(root, rel1, rel2, joinrel, sjinfo, restrictlist);
1042 315934 : }
1043 :
1044 :
1045 : /*
1046 : * have_join_order_restriction
1047 : * Detect whether the two relations should be joined to satisfy
1048 : * a join-order restriction arising from special or lateral joins.
1049 : *
1050 : * In practice this is always used with have_relevant_joinclause(), and so
1051 : * could be merged with that function, but it seems clearer to separate the
1052 : * two concerns. We need this test because there are degenerate cases where
1053 : * a clauseless join must be performed to satisfy join-order restrictions.
1054 : * Also, if one rel has a lateral reference to the other, or both are needed
1055 : * to compute some PHV, we should consider joining them even if the join would
1056 : * be clauseless.
1057 : *
1058 : * Note: this is only a problem if one side of a degenerate outer join
1059 : * contains multiple rels, or a clauseless join is required within an
1060 : * IN/EXISTS RHS; else we will find a join path via the "last ditch" case in
1061 : * join_search_one_level(). We could dispense with this test if we were
1062 : * willing to try bushy plans in the "last ditch" case, but that seems much
1063 : * less efficient.
1064 : */
1065 : bool
1066 77028 : have_join_order_restriction(PlannerInfo *root,
1067 : RelOptInfo *rel1, RelOptInfo *rel2)
1068 : {
1069 77028 : bool result = false;
1070 : ListCell *l;
1071 :
1072 : /*
1073 : * If either side has a direct lateral reference to the other, attempt the
1074 : * join regardless of outer-join considerations.
1075 : */
1076 144696 : if (bms_overlap(rel1->relids, rel2->direct_lateral_relids) ||
1077 67668 : bms_overlap(rel2->relids, rel1->direct_lateral_relids))
1078 10464 : return true;
1079 :
1080 : /*
1081 : * Likewise, if both rels are needed to compute some PlaceHolderVar,
1082 : * attempt the join regardless of outer-join considerations. (This is not
1083 : * very desirable, because a PHV with a large eval_at set will cause a lot
1084 : * of probably-useless joins to be considered, but failing to do this can
1085 : * cause us to fail to construct a plan at all.)
1086 : */
1087 68446 : foreach(l, root->placeholder_list)
1088 : {
1089 1942 : PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(l);
1090 :
1091 2332 : if (bms_is_subset(rel1->relids, phinfo->ph_eval_at) &&
1092 390 : bms_is_subset(rel2->relids, phinfo->ph_eval_at))
1093 60 : return true;
1094 : }
1095 :
1096 : /*
1097 : * It's possible that the rels correspond to the left and right sides of a
1098 : * degenerate outer join, that is, one with no joinclause mentioning the
1099 : * non-nullable side; in which case we should force the join to occur.
1100 : *
1101 : * Also, the two rels could represent a clauseless join that has to be
1102 : * completed to build up the LHS or RHS of an outer join.
1103 : */
1104 177464 : foreach(l, root->join_info_list)
1105 : {
1106 112414 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
1107 :
1108 : /* ignore full joins --- other mechanisms handle them */
1109 112414 : if (sjinfo->jointype == JOIN_FULL)
1110 42 : continue;
1111 :
1112 : /* Can we perform the SJ with these rels? */
1113 138030 : if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) &&
1114 25658 : bms_is_subset(sjinfo->min_righthand, rel2->relids))
1115 : {
1116 1076 : result = true;
1117 1076 : break;
1118 : }
1119 118204 : if (bms_is_subset(sjinfo->min_lefthand, rel2->relids) &&
1120 6908 : bms_is_subset(sjinfo->min_righthand, rel1->relids))
1121 : {
1122 210 : result = true;
1123 210 : break;
1124 : }
1125 :
1126 : /*
1127 : * Might we need to join these rels to complete the RHS? We have to
1128 : * use "overlap" tests since either rel might include a lower SJ that
1129 : * has been proven to commute with this one.
1130 : */
1131 133966 : if (bms_overlap(sjinfo->min_righthand, rel1->relids) &&
1132 22880 : bms_overlap(sjinfo->min_righthand, rel2->relids))
1133 : {
1134 120 : result = true;
1135 120 : break;
1136 : }
1137 :
1138 : /* Likewise for the LHS. */
1139 138508 : if (bms_overlap(sjinfo->min_lefthand, rel1->relids) &&
1140 27542 : bms_overlap(sjinfo->min_lefthand, rel2->relids))
1141 : {
1142 48 : result = true;
1143 48 : break;
1144 : }
1145 : }
1146 :
1147 : /*
1148 : * We do not force the join to occur if either input rel can legally be
1149 : * joined to anything else using joinclauses. This essentially means that
1150 : * clauseless bushy joins are put off as long as possible. The reason is
1151 : * that when there is a join order restriction high up in the join tree
1152 : * (that is, with many rels inside the LHS or RHS), we would otherwise
1153 : * expend lots of effort considering very stupid join combinations within
1154 : * its LHS or RHS.
1155 : */
1156 66504 : if (result)
1157 : {
1158 2770 : if (has_legal_joinclause(root, rel1) ||
1159 1316 : has_legal_joinclause(root, rel2))
1160 252 : result = false;
1161 : }
1162 :
1163 66504 : return result;
1164 : }
1165 :
1166 :
1167 : /*
1168 : * has_join_restriction
1169 : * Detect whether the specified relation has join-order restrictions,
1170 : * due to being inside an outer join or an IN (sub-SELECT),
1171 : * or participating in any LATERAL references or multi-rel PHVs.
1172 : *
1173 : * Essentially, this tests whether have_join_order_restriction() could
1174 : * succeed with this rel and some other one. It's OK if we sometimes
1175 : * say "true" incorrectly. (Therefore, we don't bother with the relatively
1176 : * expensive has_legal_joinclause test.)
1177 : */
1178 : static bool
1179 30714 : has_join_restriction(PlannerInfo *root, RelOptInfo *rel)
1180 : {
1181 : ListCell *l;
1182 :
1183 30714 : if (rel->lateral_relids != NULL || rel->lateral_referencers != NULL)
1184 17570 : return true;
1185 :
1186 13936 : foreach(l, root->placeholder_list)
1187 : {
1188 840 : PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(l);
1189 :
1190 840 : if (bms_is_subset(rel->relids, phinfo->ph_eval_at) &&
1191 204 : !bms_equal(rel->relids, phinfo->ph_eval_at))
1192 48 : return true;
1193 : }
1194 :
1195 13890 : foreach(l, root->join_info_list)
1196 : {
1197 2946 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
1198 :
1199 : /* ignore full joins --- other mechanisms preserve their ordering */
1200 2946 : if (sjinfo->jointype == JOIN_FULL)
1201 86 : continue;
1202 :
1203 : /* ignore if SJ is already contained in rel */
1204 4410 : if (bms_is_subset(sjinfo->min_lefthand, rel->relids) &&
1205 1550 : bms_is_subset(sjinfo->min_righthand, rel->relids))
1206 372 : continue;
1207 :
1208 : /* restricted if it overlaps LHS or RHS, but doesn't contain SJ */
1209 3774 : if (bms_overlap(sjinfo->min_lefthand, rel->relids) ||
1210 1286 : bms_overlap(sjinfo->min_righthand, rel->relids))
1211 2152 : return true;
1212 : }
1213 :
1214 10944 : return false;
1215 : }
1216 :
1217 :
1218 : /*
1219 : * has_legal_joinclause
1220 : * Detect whether the specified relation can legally be joined
1221 : * to any other rels using join clauses.
1222 : *
1223 : * We consider only joins to single other relations in the current
1224 : * initial_rels list. This is sufficient to get a "true" result in most real
1225 : * queries, and an occasional erroneous "false" will only cost a bit more
1226 : * planning time. The reason for this limitation is that considering joins to
1227 : * other joins would require proving that the other join rel can legally be
1228 : * formed, which seems like too much trouble for something that's only a
1229 : * heuristic to save planning time. (Note: we must look at initial_rels
1230 : * and not all of the query, since when we are planning a sub-joinlist we
1231 : * may be forced to make clauseless joins within initial_rels even though
1232 : * there are join clauses linking to other parts of the query.)
1233 : */
1234 : static bool
1235 2770 : has_legal_joinclause(PlannerInfo *root, RelOptInfo *rel)
1236 : {
1237 : ListCell *lc;
1238 :
1239 10218 : foreach(lc, root->initial_rels)
1240 : {
1241 7700 : RelOptInfo *rel2 = (RelOptInfo *) lfirst(lc);
1242 :
1243 : /* ignore rels that are already in "rel" */
1244 7700 : if (bms_overlap(rel->relids, rel2->relids))
1245 3274 : continue;
1246 :
1247 4426 : if (have_relevant_joinclause(root, rel, rel2))
1248 : {
1249 : Relids joinrelids;
1250 : SpecialJoinInfo *sjinfo;
1251 : bool reversed;
1252 :
1253 : /* join_is_legal needs relids of the union */
1254 408 : joinrelids = bms_union(rel->relids, rel2->relids);
1255 :
1256 408 : if (join_is_legal(root, rel, rel2, joinrelids,
1257 : &sjinfo, &reversed))
1258 : {
1259 : /* Yes, this will work */
1260 252 : bms_free(joinrelids);
1261 252 : return true;
1262 : }
1263 :
1264 156 : bms_free(joinrelids);
1265 : }
1266 : }
1267 :
1268 2518 : return false;
1269 : }
1270 :
1271 :
1272 : /*
1273 : * is_dummy_rel --- has relation been proven empty?
1274 : */
1275 : bool
1276 2522736 : is_dummy_rel(RelOptInfo *rel)
1277 : {
1278 : Path *path;
1279 :
1280 : /*
1281 : * A rel that is known dummy will have just one path that is a childless
1282 : * Append. (Even if somehow it has more paths, a childless Append will
1283 : * have cost zero and hence should be at the front of the pathlist.)
1284 : */
1285 2522736 : if (rel->pathlist == NIL)
1286 1360658 : return false;
1287 1162078 : path = (Path *) linitial(rel->pathlist);
1288 :
1289 : /*
1290 : * Initially, a dummy path will just be a childless Append. But in later
1291 : * planning stages we might stick a ProjectSetPath and/or ProjectionPath
1292 : * on top, since Append can't project. Rather than make assumptions about
1293 : * which combinations can occur, just descend through whatever we find.
1294 : */
1295 : for (;;)
1296 : {
1297 1205898 : if (IsA(path, ProjectionPath))
1298 34764 : path = ((ProjectionPath *) path)->subpath;
1299 1171134 : else if (IsA(path, ProjectSetPath))
1300 9056 : path = ((ProjectSetPath *) path)->subpath;
1301 : else
1302 1162078 : break;
1303 : }
1304 1162078 : if (IS_DUMMY_APPEND(path))
1305 4172 : return true;
1306 1157906 : return false;
1307 : }
1308 :
1309 : /*
1310 : * Mark a relation as proven empty.
1311 : *
1312 : * During GEQO planning, this can get invoked more than once on the same
1313 : * baserel struct, so it's worth checking to see if the rel is already marked
1314 : * dummy.
1315 : *
1316 : * Also, when called during GEQO join planning, we are in a short-lived
1317 : * memory context. We must make sure that the dummy path attached to a
1318 : * baserel survives the GEQO cycle, else the baserel is trashed for future
1319 : * GEQO cycles. On the other hand, when we are marking a joinrel during GEQO,
1320 : * we don't want the dummy path to clutter the main planning context. Upshot
1321 : * is that the best solution is to explicitly make the dummy path in the same
1322 : * context the given RelOptInfo is in.
1323 : */
1324 : void
1325 584 : mark_dummy_rel(RelOptInfo *rel)
1326 : {
1327 : MemoryContext oldcontext;
1328 :
1329 : /* Already marked? */
1330 584 : if (is_dummy_rel(rel))
1331 18 : return;
1332 :
1333 : /* No, so choose correct context to make the dummy path in */
1334 566 : oldcontext = MemoryContextSwitchTo(GetMemoryChunkContext(rel));
1335 :
1336 : /* Set dummy size estimate */
1337 566 : rel->rows = 0;
1338 :
1339 : /* Evict any previously chosen paths */
1340 566 : rel->pathlist = NIL;
1341 566 : rel->partial_pathlist = NIL;
1342 :
1343 : /* Set up the dummy path */
1344 566 : add_path(rel, (Path *) create_append_path(NULL, rel, NIL, NIL,
1345 : NIL, rel->lateral_relids,
1346 : 0, false, -1));
1347 :
1348 : /* Set or update cheapest_total_path and related fields */
1349 566 : set_cheapest(rel);
1350 :
1351 566 : MemoryContextSwitchTo(oldcontext);
1352 : }
1353 :
1354 :
1355 : /*
1356 : * restriction_is_constant_false --- is a restrictlist just FALSE?
1357 : *
1358 : * In cases where a qual is provably constant FALSE, eval_const_expressions
1359 : * will generally have thrown away anything that's ANDed with it. In outer
1360 : * join situations this will leave us computing cartesian products only to
1361 : * decide there's no match for an outer row, which is pretty stupid. So,
1362 : * we need to detect the case.
1363 : *
1364 : * If only_pushed_down is true, then consider only quals that are pushed-down
1365 : * from the point of view of the joinrel.
1366 : */
1367 : static bool
1368 422606 : restriction_is_constant_false(List *restrictlist,
1369 : RelOptInfo *joinrel,
1370 : bool only_pushed_down)
1371 : {
1372 : ListCell *lc;
1373 :
1374 : /*
1375 : * Despite the above comment, the restriction list we see here might
1376 : * possibly have other members besides the FALSE constant, since other
1377 : * quals could get "pushed down" to the outer join level. So we check
1378 : * each member of the list.
1379 : */
1380 895734 : foreach(lc, restrictlist)
1381 : {
1382 473568 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
1383 :
1384 473568 : if (only_pushed_down && !RINFO_IS_PUSHED_DOWN(rinfo, joinrel->relids))
1385 126462 : continue;
1386 :
1387 347106 : if (rinfo->clause && IsA(rinfo->clause, Const))
1388 : {
1389 5238 : Const *con = (Const *) rinfo->clause;
1390 :
1391 : /* constant NULL is as good as constant FALSE for our purposes */
1392 5238 : if (con->constisnull)
1393 440 : return true;
1394 5130 : if (!DatumGetBool(con->constvalue))
1395 332 : return true;
1396 : }
1397 : }
1398 422166 : return false;
1399 : }
1400 :
1401 : /*
1402 : * Assess whether join between given two partitioned relations can be broken
1403 : * down into joins between matching partitions; a technique called
1404 : * "partitionwise join"
1405 : *
1406 : * Partitionwise join is possible when a. Joining relations have same
1407 : * partitioning scheme b. There exists an equi-join between the partition keys
1408 : * of the two relations.
1409 : *
1410 : * Partitionwise join is planned as follows (details: optimizer/README.)
1411 : *
1412 : * 1. Create the RelOptInfos for joins between matching partitions i.e
1413 : * child-joins and add paths to them.
1414 : *
1415 : * 2. Construct Append or MergeAppend paths across the set of child joins.
1416 : * This second phase is implemented by generate_partitionwise_join_paths().
1417 : *
1418 : * The RelOptInfo, SpecialJoinInfo and restrictlist for each child join are
1419 : * obtained by translating the respective parent join structures.
1420 : */
1421 : static void
1422 315934 : try_partitionwise_join(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2,
1423 : RelOptInfo *joinrel, SpecialJoinInfo *parent_sjinfo,
1424 : List *parent_restrictlist)
1425 : {
1426 315934 : bool rel1_is_simple = IS_SIMPLE_REL(rel1);
1427 315934 : bool rel2_is_simple = IS_SIMPLE_REL(rel2);
1428 315934 : List *parts1 = NIL;
1429 315934 : List *parts2 = NIL;
1430 315934 : ListCell *lcr1 = NULL;
1431 315934 : ListCell *lcr2 = NULL;
1432 : int cnt_parts;
1433 :
1434 : /* Guard against stack overflow due to overly deep partition hierarchy. */
1435 315934 : check_stack_depth();
1436 :
1437 : /* Nothing to do, if the join relation is not partitioned. */
1438 315934 : if (joinrel->part_scheme == NULL || joinrel->nparts == 0)
1439 313832 : return;
1440 :
1441 : /* The join relation should have consider_partitionwise_join set. */
1442 : Assert(joinrel->consider_partitionwise_join);
1443 :
1444 : /*
1445 : * We can not perform partitionwise join if either of the joining
1446 : * relations is not partitioned.
1447 : */
1448 2240 : if (!IS_PARTITIONED_REL(rel1) || !IS_PARTITIONED_REL(rel2))
1449 18 : return;
1450 :
1451 : Assert(REL_HAS_ALL_PART_PROPS(rel1) && REL_HAS_ALL_PART_PROPS(rel2));
1452 :
1453 : /* The joining relations should have consider_partitionwise_join set. */
1454 : Assert(rel1->consider_partitionwise_join &&
1455 : rel2->consider_partitionwise_join);
1456 :
1457 : /*
1458 : * The partition scheme of the join relation should match that of the
1459 : * joining relations.
1460 : */
1461 : Assert(joinrel->part_scheme == rel1->part_scheme &&
1462 : joinrel->part_scheme == rel2->part_scheme);
1463 :
1464 : Assert(!(joinrel->partbounds_merged && (joinrel->nparts <= 0)));
1465 :
1466 2222 : compute_partition_bounds(root, rel1, rel2, joinrel, parent_sjinfo,
1467 : &parts1, &parts2);
1468 :
1469 2222 : if (joinrel->partbounds_merged)
1470 : {
1471 768 : lcr1 = list_head(parts1);
1472 768 : lcr2 = list_head(parts2);
1473 : }
1474 :
1475 : /*
1476 : * Create child-join relations for this partitioned join, if those don't
1477 : * exist. Add paths to child-joins for a pair of child relations
1478 : * corresponding to the given pair of parent relations.
1479 : */
1480 7832 : for (cnt_parts = 0; cnt_parts < joinrel->nparts; cnt_parts++)
1481 : {
1482 : RelOptInfo *child_rel1;
1483 : RelOptInfo *child_rel2;
1484 : bool rel1_empty;
1485 : bool rel2_empty;
1486 : SpecialJoinInfo *child_sjinfo;
1487 : List *child_restrictlist;
1488 : RelOptInfo *child_joinrel;
1489 : AppendRelInfo **appinfos;
1490 : int nappinfos;
1491 : Relids child_relids;
1492 :
1493 5730 : if (joinrel->partbounds_merged)
1494 : {
1495 2010 : child_rel1 = lfirst_node(RelOptInfo, lcr1);
1496 2010 : child_rel2 = lfirst_node(RelOptInfo, lcr2);
1497 2010 : lcr1 = lnext(parts1, lcr1);
1498 2010 : lcr2 = lnext(parts2, lcr2);
1499 : }
1500 : else
1501 : {
1502 3720 : child_rel1 = rel1->part_rels[cnt_parts];
1503 3720 : child_rel2 = rel2->part_rels[cnt_parts];
1504 : }
1505 :
1506 5730 : rel1_empty = (child_rel1 == NULL || IS_DUMMY_REL(child_rel1));
1507 5730 : rel2_empty = (child_rel2 == NULL || IS_DUMMY_REL(child_rel2));
1508 :
1509 : /*
1510 : * Check for cases where we can prove that this segment of the join
1511 : * returns no rows, due to one or both inputs being empty (including
1512 : * inputs that have been pruned away entirely). If so just ignore it.
1513 : * These rules are equivalent to populate_joinrel_with_paths's rules
1514 : * for dummy input relations.
1515 : */
1516 5730 : switch (parent_sjinfo->jointype)
1517 : {
1518 2912 : case JOIN_INNER:
1519 : case JOIN_SEMI:
1520 2912 : if (rel1_empty || rel2_empty)
1521 64 : continue; /* ignore this join segment */
1522 2876 : break;
1523 2096 : case JOIN_LEFT:
1524 : case JOIN_ANTI:
1525 2096 : if (rel1_empty)
1526 28 : continue; /* ignore this join segment */
1527 2068 : break;
1528 722 : case JOIN_FULL:
1529 722 : if (rel1_empty && rel2_empty)
1530 0 : continue; /* ignore this join segment */
1531 722 : break;
1532 0 : default:
1533 : /* other values not expected here */
1534 0 : elog(ERROR, "unrecognized join type: %d",
1535 : (int) parent_sjinfo->jointype);
1536 : break;
1537 : }
1538 :
1539 : /*
1540 : * If a child has been pruned entirely then we can't generate paths
1541 : * for it, so we have to reject partitionwise joining unless we were
1542 : * able to eliminate this partition above.
1543 : */
1544 5666 : if (child_rel1 == NULL || child_rel2 == NULL)
1545 : {
1546 : /*
1547 : * Mark the joinrel as unpartitioned so that later functions treat
1548 : * it correctly.
1549 : */
1550 120 : joinrel->nparts = 0;
1551 120 : return;
1552 : }
1553 :
1554 : /*
1555 : * If a leaf relation has consider_partitionwise_join=false, it means
1556 : * that it's a dummy relation for which we skipped setting up tlist
1557 : * expressions and adding EC members in set_append_rel_size(), so
1558 : * again we have to fail here.
1559 : */
1560 5546 : if (rel1_is_simple && !child_rel1->consider_partitionwise_join)
1561 : {
1562 : Assert(child_rel1->reloptkind == RELOPT_OTHER_MEMBER_REL);
1563 : Assert(IS_DUMMY_REL(child_rel1));
1564 0 : joinrel->nparts = 0;
1565 0 : return;
1566 : }
1567 5546 : if (rel2_is_simple && !child_rel2->consider_partitionwise_join)
1568 : {
1569 : Assert(child_rel2->reloptkind == RELOPT_OTHER_MEMBER_REL);
1570 : Assert(IS_DUMMY_REL(child_rel2));
1571 0 : joinrel->nparts = 0;
1572 0 : return;
1573 : }
1574 :
1575 : /* We should never try to join two overlapping sets of rels. */
1576 : Assert(!bms_overlap(child_rel1->relids, child_rel2->relids));
1577 :
1578 : /*
1579 : * Construct SpecialJoinInfo from parent join relations's
1580 : * SpecialJoinInfo.
1581 : */
1582 5546 : child_sjinfo = build_child_join_sjinfo(root, parent_sjinfo,
1583 : child_rel1->relids,
1584 : child_rel2->relids);
1585 :
1586 : /* Find the AppendRelInfo structures */
1587 5546 : child_relids = bms_union(child_rel1->relids, child_rel2->relids);
1588 5546 : appinfos = find_appinfos_by_relids(root, child_relids,
1589 : &nappinfos);
1590 :
1591 : /*
1592 : * Construct restrictions applicable to the child join from those
1593 : * applicable to the parent join.
1594 : */
1595 : child_restrictlist =
1596 5546 : (List *) adjust_appendrel_attrs(root,
1597 : (Node *) parent_restrictlist,
1598 : nappinfos, appinfos);
1599 :
1600 : /* Find or construct the child join's RelOptInfo */
1601 5546 : child_joinrel = joinrel->part_rels[cnt_parts];
1602 5546 : if (!child_joinrel)
1603 : {
1604 5002 : child_joinrel = build_child_join_rel(root, child_rel1, child_rel2,
1605 : joinrel, child_restrictlist,
1606 : child_sjinfo, nappinfos, appinfos);
1607 5002 : joinrel->part_rels[cnt_parts] = child_joinrel;
1608 5002 : joinrel->live_parts = bms_add_member(joinrel->live_parts, cnt_parts);
1609 5002 : joinrel->all_partrels = bms_add_members(joinrel->all_partrels,
1610 5002 : child_joinrel->relids);
1611 : }
1612 :
1613 : /* Assert we got the right one */
1614 : Assert(bms_equal(child_joinrel->relids,
1615 : adjust_child_relids(joinrel->relids,
1616 : nappinfos, appinfos)));
1617 :
1618 : /* And make paths for the child join */
1619 5546 : populate_joinrel_with_paths(root, child_rel1, child_rel2,
1620 : child_joinrel, child_sjinfo,
1621 : child_restrictlist);
1622 :
1623 : /*
1624 : * When there are thousands of partitions involved, this loop will
1625 : * accumulate a significant amount of memory usage from objects that
1626 : * are only needed within the loop. Free these local objects eagerly
1627 : * at the end of each iteration.
1628 : */
1629 5546 : pfree(appinfos);
1630 5546 : bms_free(child_relids);
1631 5546 : free_child_join_sjinfo(child_sjinfo, parent_sjinfo);
1632 : }
1633 : }
1634 :
1635 : /*
1636 : * Construct the SpecialJoinInfo for a child-join by translating
1637 : * SpecialJoinInfo for the join between parents. left_relids and right_relids
1638 : * are the relids of left and right side of the join respectively.
1639 : *
1640 : * If translations are added to or removed from this function, consider
1641 : * updating free_child_join_sjinfo() accordingly.
1642 : */
1643 : static SpecialJoinInfo *
1644 5546 : build_child_join_sjinfo(PlannerInfo *root, SpecialJoinInfo *parent_sjinfo,
1645 : Relids left_relids, Relids right_relids)
1646 : {
1647 5546 : SpecialJoinInfo *sjinfo = makeNode(SpecialJoinInfo);
1648 : AppendRelInfo **left_appinfos;
1649 : int left_nappinfos;
1650 : AppendRelInfo **right_appinfos;
1651 : int right_nappinfos;
1652 :
1653 : /* Dummy SpecialJoinInfos can be created without any translation. */
1654 5546 : if (parent_sjinfo->jointype == JOIN_INNER)
1655 : {
1656 : Assert(parent_sjinfo->ojrelid == 0);
1657 2372 : init_dummy_sjinfo(sjinfo, left_relids, right_relids);
1658 2372 : return sjinfo;
1659 : }
1660 :
1661 3174 : memcpy(sjinfo, parent_sjinfo, sizeof(SpecialJoinInfo));
1662 3174 : left_appinfos = find_appinfos_by_relids(root, left_relids,
1663 : &left_nappinfos);
1664 3174 : right_appinfos = find_appinfos_by_relids(root, right_relids,
1665 : &right_nappinfos);
1666 :
1667 3174 : sjinfo->min_lefthand = adjust_child_relids(sjinfo->min_lefthand,
1668 : left_nappinfos, left_appinfos);
1669 3174 : sjinfo->min_righthand = adjust_child_relids(sjinfo->min_righthand,
1670 : right_nappinfos,
1671 : right_appinfos);
1672 3174 : sjinfo->syn_lefthand = adjust_child_relids(sjinfo->syn_lefthand,
1673 : left_nappinfos, left_appinfos);
1674 3174 : sjinfo->syn_righthand = adjust_child_relids(sjinfo->syn_righthand,
1675 : right_nappinfos,
1676 : right_appinfos);
1677 : /* outer-join relids need no adjustment */
1678 6348 : sjinfo->semi_rhs_exprs = (List *) adjust_appendrel_attrs(root,
1679 3174 : (Node *) sjinfo->semi_rhs_exprs,
1680 : right_nappinfos,
1681 : right_appinfos);
1682 :
1683 3174 : pfree(left_appinfos);
1684 3174 : pfree(right_appinfos);
1685 :
1686 3174 : return sjinfo;
1687 : }
1688 :
1689 : /*
1690 : * free_child_join_sjinfo
1691 : * Free memory consumed by a SpecialJoinInfo created by
1692 : * build_child_join_sjinfo()
1693 : *
1694 : * Only members that are translated copies of their counterpart in the parent
1695 : * SpecialJoinInfo are freed here.
1696 : */
1697 : static void
1698 5546 : free_child_join_sjinfo(SpecialJoinInfo *child_sjinfo,
1699 : SpecialJoinInfo *parent_sjinfo)
1700 : {
1701 : /*
1702 : * Dummy SpecialJoinInfos of inner joins do not have any translated fields
1703 : * and hence no fields that to be freed.
1704 : */
1705 5546 : if (child_sjinfo->jointype != JOIN_INNER)
1706 : {
1707 3174 : if (child_sjinfo->min_lefthand != parent_sjinfo->min_lefthand)
1708 3156 : bms_free(child_sjinfo->min_lefthand);
1709 :
1710 3174 : if (child_sjinfo->min_righthand != parent_sjinfo->min_righthand)
1711 3174 : bms_free(child_sjinfo->min_righthand);
1712 :
1713 3174 : if (child_sjinfo->syn_lefthand != parent_sjinfo->syn_lefthand)
1714 3174 : bms_free(child_sjinfo->syn_lefthand);
1715 :
1716 3174 : if (child_sjinfo->syn_righthand != parent_sjinfo->syn_righthand)
1717 3174 : bms_free(child_sjinfo->syn_righthand);
1718 :
1719 : Assert(child_sjinfo->commute_above_l == parent_sjinfo->commute_above_l);
1720 : Assert(child_sjinfo->commute_above_r == parent_sjinfo->commute_above_r);
1721 : Assert(child_sjinfo->commute_below_l == parent_sjinfo->commute_below_l);
1722 : Assert(child_sjinfo->commute_below_r == parent_sjinfo->commute_below_r);
1723 :
1724 : Assert(child_sjinfo->semi_operators == parent_sjinfo->semi_operators);
1725 :
1726 : /*
1727 : * semi_rhs_exprs may in principle be freed, but a simple pfree() does
1728 : * not suffice, so we leave it alone.
1729 : */
1730 : }
1731 :
1732 5546 : pfree(child_sjinfo);
1733 5546 : }
1734 :
1735 : /*
1736 : * compute_partition_bounds
1737 : * Compute the partition bounds for a join rel from those for inputs
1738 : */
1739 : static void
1740 2222 : compute_partition_bounds(PlannerInfo *root, RelOptInfo *rel1,
1741 : RelOptInfo *rel2, RelOptInfo *joinrel,
1742 : SpecialJoinInfo *parent_sjinfo,
1743 : List **parts1, List **parts2)
1744 : {
1745 : /*
1746 : * If we don't have the partition bounds for the join rel yet, try to
1747 : * compute those along with pairs of partitions to be joined.
1748 : */
1749 2222 : if (joinrel->nparts == -1)
1750 : {
1751 2034 : PartitionScheme part_scheme = joinrel->part_scheme;
1752 2034 : PartitionBoundInfo boundinfo = NULL;
1753 2034 : int nparts = 0;
1754 :
1755 : Assert(joinrel->boundinfo == NULL);
1756 : Assert(joinrel->part_rels == NULL);
1757 :
1758 : /*
1759 : * See if the partition bounds for inputs are exactly the same, in
1760 : * which case we don't need to work hard: the join rel will have the
1761 : * same partition bounds as inputs, and the partitions with the same
1762 : * cardinal positions will form the pairs.
1763 : *
1764 : * Note: even in cases where one or both inputs have merged bounds, it
1765 : * would be possible for both the bounds to be exactly the same, but
1766 : * it seems unlikely to be worth the cycles to check.
1767 : */
1768 2034 : if (!rel1->partbounds_merged &&
1769 1974 : !rel2->partbounds_merged &&
1770 3690 : rel1->nparts == rel2->nparts &&
1771 1716 : partition_bounds_equal(part_scheme->partnatts,
1772 : part_scheme->parttyplen,
1773 : part_scheme->parttypbyval,
1774 : rel1->boundinfo, rel2->boundinfo))
1775 : {
1776 1188 : boundinfo = rel1->boundinfo;
1777 1188 : nparts = rel1->nparts;
1778 : }
1779 : else
1780 : {
1781 : /* Try merging the partition bounds for inputs. */
1782 846 : boundinfo = partition_bounds_merge(part_scheme->partnatts,
1783 846 : part_scheme->partsupfunc,
1784 : part_scheme->partcollation,
1785 : rel1, rel2,
1786 : parent_sjinfo->jointype,
1787 : parts1, parts2);
1788 846 : if (boundinfo == NULL)
1789 : {
1790 114 : joinrel->nparts = 0;
1791 114 : return;
1792 : }
1793 732 : nparts = list_length(*parts1);
1794 732 : joinrel->partbounds_merged = true;
1795 : }
1796 :
1797 : Assert(nparts > 0);
1798 1920 : joinrel->boundinfo = boundinfo;
1799 1920 : joinrel->nparts = nparts;
1800 1920 : joinrel->part_rels =
1801 1920 : (RelOptInfo **) palloc0(sizeof(RelOptInfo *) * nparts);
1802 : }
1803 : else
1804 : {
1805 : Assert(joinrel->nparts > 0);
1806 : Assert(joinrel->boundinfo);
1807 : Assert(joinrel->part_rels);
1808 :
1809 : /*
1810 : * If the join rel's partbounds_merged flag is true, it means inputs
1811 : * are not guaranteed to have the same partition bounds, therefore we
1812 : * can't assume that the partitions at the same cardinal positions
1813 : * form the pairs; let get_matching_part_pairs() generate the pairs.
1814 : * Otherwise, nothing to do since we can assume that.
1815 : */
1816 188 : if (joinrel->partbounds_merged)
1817 : {
1818 36 : get_matching_part_pairs(root, joinrel, rel1, rel2,
1819 : parts1, parts2);
1820 : Assert(list_length(*parts1) == joinrel->nparts);
1821 : Assert(list_length(*parts2) == joinrel->nparts);
1822 : }
1823 : }
1824 : }
1825 :
1826 : /*
1827 : * get_matching_part_pairs
1828 : * Generate pairs of partitions to be joined from inputs
1829 : */
1830 : static void
1831 36 : get_matching_part_pairs(PlannerInfo *root, RelOptInfo *joinrel,
1832 : RelOptInfo *rel1, RelOptInfo *rel2,
1833 : List **parts1, List **parts2)
1834 : {
1835 36 : bool rel1_is_simple = IS_SIMPLE_REL(rel1);
1836 36 : bool rel2_is_simple = IS_SIMPLE_REL(rel2);
1837 : int cnt_parts;
1838 :
1839 36 : *parts1 = NIL;
1840 36 : *parts2 = NIL;
1841 :
1842 132 : for (cnt_parts = 0; cnt_parts < joinrel->nparts; cnt_parts++)
1843 : {
1844 96 : RelOptInfo *child_joinrel = joinrel->part_rels[cnt_parts];
1845 : RelOptInfo *child_rel1;
1846 : RelOptInfo *child_rel2;
1847 : Relids child_relids1;
1848 : Relids child_relids2;
1849 :
1850 : /*
1851 : * If this segment of the join is empty, it means that this segment
1852 : * was ignored when previously creating child-join paths for it in
1853 : * try_partitionwise_join() as it would not contribute to the join
1854 : * result, due to one or both inputs being empty; add NULL to each of
1855 : * the given lists so that this segment will be ignored again in that
1856 : * function.
1857 : */
1858 96 : if (!child_joinrel)
1859 : {
1860 0 : *parts1 = lappend(*parts1, NULL);
1861 0 : *parts2 = lappend(*parts2, NULL);
1862 0 : continue;
1863 : }
1864 :
1865 : /*
1866 : * Get a relids set of partition(s) involved in this join segment that
1867 : * are from the rel1 side.
1868 : */
1869 96 : child_relids1 = bms_intersect(child_joinrel->relids,
1870 96 : rel1->all_partrels);
1871 : Assert(bms_num_members(child_relids1) == bms_num_members(rel1->relids));
1872 :
1873 : /*
1874 : * Get a child rel for rel1 with the relids. Note that we should have
1875 : * the child rel even if rel1 is a join rel, because in that case the
1876 : * partitions specified in the relids would have matching/overlapping
1877 : * boundaries, so the specified partitions should be considered as
1878 : * ones to be joined when planning partitionwise joins of rel1,
1879 : * meaning that the child rel would have been built by the time we get
1880 : * here.
1881 : */
1882 96 : if (rel1_is_simple)
1883 : {
1884 0 : int varno = bms_singleton_member(child_relids1);
1885 :
1886 0 : child_rel1 = find_base_rel(root, varno);
1887 : }
1888 : else
1889 96 : child_rel1 = find_join_rel(root, child_relids1);
1890 : Assert(child_rel1);
1891 :
1892 : /*
1893 : * Get a relids set of partition(s) involved in this join segment that
1894 : * are from the rel2 side.
1895 : */
1896 96 : child_relids2 = bms_intersect(child_joinrel->relids,
1897 96 : rel2->all_partrels);
1898 : Assert(bms_num_members(child_relids2) == bms_num_members(rel2->relids));
1899 :
1900 : /*
1901 : * Get a child rel for rel2 with the relids. See above comments.
1902 : */
1903 96 : if (rel2_is_simple)
1904 : {
1905 96 : int varno = bms_singleton_member(child_relids2);
1906 :
1907 96 : child_rel2 = find_base_rel(root, varno);
1908 : }
1909 : else
1910 0 : child_rel2 = find_join_rel(root, child_relids2);
1911 : Assert(child_rel2);
1912 :
1913 : /*
1914 : * The join of rel1 and rel2 is legal, so is the join of the child
1915 : * rels obtained above; add them to the given lists as a join pair
1916 : * producing this join segment.
1917 : */
1918 96 : *parts1 = lappend(*parts1, child_rel1);
1919 96 : *parts2 = lappend(*parts2, child_rel2);
1920 : }
1921 36 : }
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