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 "partitioning/partbounds.h"
23 : #include "utils/memutils.h"
24 :
25 :
26 : static void make_rels_by_clause_joins(PlannerInfo *root,
27 : RelOptInfo *old_rel,
28 : List *other_rels,
29 : int first_rel_idx);
30 : static void make_rels_by_clauseless_joins(PlannerInfo *root,
31 : RelOptInfo *old_rel,
32 : List *other_rels);
33 : static bool has_join_restriction(PlannerInfo *root, RelOptInfo *rel);
34 : static bool has_legal_joinclause(PlannerInfo *root, RelOptInfo *rel);
35 : static bool restriction_is_constant_false(List *restrictlist,
36 : RelOptInfo *joinrel,
37 : bool only_pushed_down);
38 : static void populate_joinrel_with_paths(PlannerInfo *root, RelOptInfo *rel1,
39 : RelOptInfo *rel2, RelOptInfo *joinrel,
40 : SpecialJoinInfo *sjinfo, List *restrictlist);
41 : static void try_partitionwise_join(PlannerInfo *root, RelOptInfo *rel1,
42 : RelOptInfo *rel2, RelOptInfo *joinrel,
43 : SpecialJoinInfo *parent_sjinfo,
44 : List *parent_restrictlist);
45 : static SpecialJoinInfo *build_child_join_sjinfo(PlannerInfo *root,
46 : SpecialJoinInfo *parent_sjinfo,
47 : Relids left_relids, Relids right_relids);
48 : static void free_child_join_sjinfo(SpecialJoinInfo *child_sjinfo,
49 : SpecialJoinInfo *parent_sjinfo);
50 : static void compute_partition_bounds(PlannerInfo *root, RelOptInfo *rel1,
51 : RelOptInfo *rel2, RelOptInfo *joinrel,
52 : SpecialJoinInfo *parent_sjinfo,
53 : List **parts1, List **parts2);
54 : static void get_matching_part_pairs(PlannerInfo *root, RelOptInfo *joinrel,
55 : RelOptInfo *rel1, RelOptInfo *rel2,
56 : List **parts1, List **parts2);
57 :
58 :
59 : /*
60 : * join_search_one_level
61 : * Consider ways to produce join relations containing exactly 'level'
62 : * jointree items. (This is one step of the dynamic-programming method
63 : * embodied in standard_join_search.) Join rel nodes for each feasible
64 : * combination of lower-level rels are created and returned in a list.
65 : * Implementation paths are created for each such joinrel, too.
66 : *
67 : * level: level of rels we want to make this time
68 : * root->join_rel_level[j], 1 <= j < level, is a list of rels containing j items
69 : *
70 : * The result is returned in root->join_rel_level[level].
71 : */
72 : void
73 134160 : join_search_one_level(PlannerInfo *root, int level)
74 : {
75 134160 : List **joinrels = root->join_rel_level;
76 : ListCell *r;
77 : int k;
78 :
79 : Assert(joinrels[level] == NIL);
80 :
81 : /* Set join_cur_level so that new joinrels are added to proper list */
82 134160 : root->join_cur_level = level;
83 :
84 : /*
85 : * First, consider left-sided and right-sided plans, in which rels of
86 : * exactly level-1 member relations are joined against initial relations.
87 : * We prefer to join using join clauses, but if we find a rel of level-1
88 : * members that has no join clauses, we will generate Cartesian-product
89 : * joins against all initial rels not already contained in it.
90 : */
91 477608 : foreach(r, joinrels[level - 1])
92 : {
93 343448 : RelOptInfo *old_rel = (RelOptInfo *) lfirst(r);
94 :
95 373982 : if (old_rel->joininfo != NIL || old_rel->has_eclass_joins ||
96 30534 : has_join_restriction(root, old_rel))
97 333066 : {
98 : int first_rel;
99 :
100 : /*
101 : * There are join clauses or join order restrictions relevant to
102 : * this rel, so consider joins between this rel and (only) those
103 : * initial rels it is linked to by a clause or restriction.
104 : *
105 : * At level 2 this condition is symmetric, so there is no need to
106 : * look at initial rels before this one in the list; we already
107 : * considered such joins when we were at the earlier rel. (The
108 : * mirror-image joins are handled automatically by make_join_rel.)
109 : * In later passes (level > 2), we join rels of the previous level
110 : * to each initial rel they don't already include but have a join
111 : * clause or restriction with.
112 : */
113 333066 : if (level == 2) /* consider remaining initial rels */
114 222202 : first_rel = foreach_current_index(r) + 1;
115 : else
116 110864 : first_rel = 0;
117 :
118 333066 : make_rels_by_clause_joins(root, old_rel, joinrels[1], first_rel);
119 : }
120 : else
121 : {
122 : /*
123 : * Oops, we have a relation that is not joined to any other
124 : * relation, either directly or by join-order restrictions.
125 : * Cartesian product time.
126 : *
127 : * We consider a cartesian product with each not-already-included
128 : * initial rel, whether it has other join clauses or not. At
129 : * level 2, if there are two or more clauseless initial rels, we
130 : * will redundantly consider joining them in both directions; but
131 : * such cases aren't common enough to justify adding complexity to
132 : * avoid the duplicated effort.
133 : */
134 10382 : make_rels_by_clauseless_joins(root,
135 : old_rel,
136 10382 : joinrels[1]);
137 : }
138 : }
139 :
140 : /*
141 : * Now, consider "bushy plans" in which relations of k initial rels are
142 : * joined to relations of level-k initial rels, for 2 <= k <= level-2.
143 : *
144 : * We only consider bushy-plan joins for pairs of rels where there is a
145 : * suitable join clause (or join order restriction), in order to avoid
146 : * unreasonable growth of planning time.
147 : */
148 134160 : for (k = 2;; k++)
149 13548 : {
150 147708 : int other_level = level - k;
151 :
152 : /*
153 : * Since make_join_rel(x, y) handles both x,y and y,x cases, we only
154 : * need to go as far as the halfway point.
155 : */
156 147708 : if (k > other_level)
157 134160 : break;
158 :
159 71702 : foreach(r, joinrels[k])
160 : {
161 58154 : RelOptInfo *old_rel = (RelOptInfo *) lfirst(r);
162 : int first_rel;
163 : ListCell *r2;
164 :
165 : /*
166 : * We can ignore relations without join clauses here, unless they
167 : * participate in join-order restrictions --- then we might have
168 : * to force a bushy join plan.
169 : */
170 58154 : if (old_rel->joininfo == NIL && !old_rel->has_eclass_joins &&
171 312 : !has_join_restriction(root, old_rel))
172 216 : continue;
173 :
174 57938 : if (k == other_level) /* only consider remaining rels */
175 39186 : first_rel = foreach_current_index(r) + 1;
176 : else
177 18752 : first_rel = 0;
178 :
179 263154 : for_each_from(r2, joinrels[other_level], first_rel)
180 : {
181 205216 : RelOptInfo *new_rel = (RelOptInfo *) lfirst(r2);
182 :
183 205216 : if (!bms_overlap(old_rel->relids, new_rel->relids))
184 : {
185 : /*
186 : * OK, we can build a rel of the right level from this
187 : * pair of rels. Do so if there is at least one relevant
188 : * join clause or join order restriction.
189 : */
190 23504 : if (have_relevant_joinclause(root, old_rel, new_rel) ||
191 1142 : have_join_order_restriction(root, old_rel, new_rel))
192 : {
193 21274 : (void) make_join_rel(root, old_rel, new_rel);
194 : }
195 : }
196 : }
197 : }
198 : }
199 :
200 : /*----------
201 : * Last-ditch effort: if we failed to find any usable joins so far, force
202 : * a set of cartesian-product joins to be generated. This handles the
203 : * special case where all the available rels have join clauses but we
204 : * cannot use any of those clauses yet. This can only happen when we are
205 : * considering a join sub-problem (a sub-joinlist) and all the rels in the
206 : * sub-problem have only join clauses with rels outside the sub-problem.
207 : * An example is
208 : *
209 : * SELECT ... FROM a INNER JOIN b ON TRUE, c, d, ...
210 : * WHERE a.w = c.x and b.y = d.z;
211 : *
212 : * If the "a INNER JOIN b" sub-problem does not get flattened into the
213 : * upper level, we must be willing to make a cartesian join of a and b;
214 : * but the code above will not have done so, because it thought that both
215 : * a and b have joinclauses. We consider only left-sided and right-sided
216 : * cartesian joins in this case (no bushy).
217 : *----------
218 : */
219 134160 : if (joinrels[level] == NIL)
220 : {
221 : /*
222 : * This loop is just like the first one, except we always call
223 : * make_rels_by_clauseless_joins().
224 : */
225 54 : foreach(r, joinrels[level - 1])
226 : {
227 36 : RelOptInfo *old_rel = (RelOptInfo *) lfirst(r);
228 :
229 36 : make_rels_by_clauseless_joins(root,
230 : old_rel,
231 36 : joinrels[1]);
232 : }
233 :
234 : /*----------
235 : * When special joins are involved, there may be no legal way
236 : * to make an N-way join for some values of N. For example consider
237 : *
238 : * SELECT ... FROM t1 WHERE
239 : * x IN (SELECT ... FROM t2,t3 WHERE ...) AND
240 : * y IN (SELECT ... FROM t4,t5 WHERE ...)
241 : *
242 : * We will flatten this query to a 5-way join problem, but there are
243 : * no 4-way joins that join_is_legal() will consider legal. We have
244 : * to accept failure at level 4 and go on to discover a workable
245 : * bushy plan at level 5.
246 : *
247 : * However, if there are no special joins and no lateral references
248 : * then join_is_legal() should never fail, and so the following sanity
249 : * check is useful.
250 : *----------
251 : */
252 18 : if (joinrels[level] == NIL &&
253 6 : root->join_info_list == NIL &&
254 0 : !root->hasLateralRTEs)
255 0 : elog(ERROR, "failed to build any %d-way joins", level);
256 : }
257 134160 : }
258 :
259 : /*
260 : * make_rels_by_clause_joins
261 : * Build joins between the given relation 'old_rel' and other relations
262 : * that participate in join clauses that 'old_rel' also participates in
263 : * (or participate in join-order restrictions with it).
264 : * The join rels are returned in root->join_rel_level[join_cur_level].
265 : *
266 : * Note: at levels above 2 we will generate the same joined relation in
267 : * multiple ways --- for example (a join b) join c is the same RelOptInfo as
268 : * (b join c) join a, though the second case will add a different set of Paths
269 : * to it. This is the reason for using the join_rel_level mechanism, which
270 : * automatically ensures that each new joinrel is only added to the list once.
271 : *
272 : * 'old_rel' is the relation entry for the relation to be joined
273 : * 'other_rels': a list containing the other rels to be considered for joining
274 : * 'first_rel_idx': the first rel to be considered in 'other_rels'
275 : *
276 : * Currently, this is only used with initial rels in other_rels, but it
277 : * will work for joining to joinrels too.
278 : */
279 : static void
280 333066 : make_rels_by_clause_joins(PlannerInfo *root,
281 : RelOptInfo *old_rel,
282 : List *other_rels,
283 : int first_rel_idx)
284 : {
285 : ListCell *l;
286 :
287 995862 : for_each_from(l, other_rels, first_rel_idx)
288 : {
289 662796 : RelOptInfo *other_rel = (RelOptInfo *) lfirst(l);
290 :
291 1037138 : if (!bms_overlap(old_rel->relids, other_rel->relids) &&
292 452420 : (have_relevant_joinclause(root, old_rel, other_rel) ||
293 78078 : have_join_order_restriction(root, old_rel, other_rel)))
294 : {
295 308018 : (void) make_join_rel(root, old_rel, other_rel);
296 : }
297 : }
298 333066 : }
299 :
300 : /*
301 : * make_rels_by_clauseless_joins
302 : * Given a relation 'old_rel' and a list of other relations
303 : * 'other_rels', create a join relation between 'old_rel' and each
304 : * member of 'other_rels' that isn't already included in 'old_rel'.
305 : * The join rels are returned in root->join_rel_level[join_cur_level].
306 : *
307 : * 'old_rel' is the relation entry for the relation to be joined
308 : * 'other_rels': a list containing the other rels to be considered for joining
309 : *
310 : * Currently, this is only used with initial rels in other_rels, but it would
311 : * work for joining to joinrels too.
312 : */
313 : static void
314 10418 : make_rels_by_clauseless_joins(PlannerInfo *root,
315 : RelOptInfo *old_rel,
316 : List *other_rels)
317 : {
318 : ListCell *l;
319 :
320 32982 : foreach(l, other_rels)
321 : {
322 22564 : RelOptInfo *other_rel = (RelOptInfo *) lfirst(l);
323 :
324 22564 : if (!bms_overlap(other_rel->relids, old_rel->relids))
325 : {
326 11140 : (void) make_join_rel(root, old_rel, other_rel);
327 : }
328 : }
329 10418 : }
330 :
331 :
332 : /*
333 : * join_is_legal
334 : * Determine whether a proposed join is legal given the query's
335 : * join order constraints; and if it is, determine the join type.
336 : *
337 : * Caller must supply not only the two rels, but the union of their relids.
338 : * (We could simplify the API by computing joinrelids locally, but this
339 : * would be redundant work in the normal path through make_join_rel.
340 : * Note that this value does NOT include the RT index of any outer join that
341 : * might need to be performed here, so it's not the canonical identifier
342 : * of the join relation.)
343 : *
344 : * On success, *sjinfo_p is set to NULL if this is to be a plain inner join,
345 : * else it's set to point to the associated SpecialJoinInfo node. Also,
346 : * *reversed_p is set true if the given relations need to be swapped to
347 : * match the SpecialJoinInfo node.
348 : */
349 : static bool
350 345574 : join_is_legal(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2,
351 : Relids joinrelids,
352 : SpecialJoinInfo **sjinfo_p, bool *reversed_p)
353 : {
354 : SpecialJoinInfo *match_sjinfo;
355 : bool reversed;
356 : bool unique_ified;
357 : bool must_be_leftjoin;
358 : ListCell *l;
359 :
360 : /*
361 : * Ensure output params are set on failure return. This is just to
362 : * suppress uninitialized-variable warnings from overly anal compilers.
363 : */
364 345574 : *sjinfo_p = NULL;
365 345574 : *reversed_p = false;
366 :
367 : /*
368 : * If we have any special joins, the proposed join might be illegal; and
369 : * in any case we have to determine its join type. Scan the join info
370 : * list for matches and conflicts.
371 : */
372 345574 : match_sjinfo = NULL;
373 345574 : reversed = false;
374 345574 : unique_ified = false;
375 345574 : must_be_leftjoin = false;
376 :
377 739368 : foreach(l, root->join_info_list)
378 : {
379 403016 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
380 :
381 : /*
382 : * This special join is not relevant unless its RHS overlaps the
383 : * proposed join. (Check this first as a fast path for dismissing
384 : * most irrelevant SJs quickly.)
385 : */
386 403016 : if (!bms_overlap(sjinfo->min_righthand, joinrelids))
387 136418 : continue;
388 :
389 : /*
390 : * Also, not relevant if proposed join is fully contained within RHS
391 : * (ie, we're still building up the RHS).
392 : */
393 266598 : if (bms_is_subset(joinrelids, sjinfo->min_righthand))
394 5266 : continue;
395 :
396 : /*
397 : * Also, not relevant if SJ is already done within either input.
398 : */
399 489706 : if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) &&
400 228374 : bms_is_subset(sjinfo->min_righthand, rel1->relids))
401 114362 : continue;
402 168956 : if (bms_is_subset(sjinfo->min_lefthand, rel2->relids) &&
403 21986 : bms_is_subset(sjinfo->min_righthand, rel2->relids))
404 11910 : continue;
405 :
406 : /*
407 : * If it's a semijoin and we already joined the RHS to any other rels
408 : * within either input, then we must have unique-ified the RHS at that
409 : * point (see below). Therefore the semijoin is no longer relevant in
410 : * this join path.
411 : */
412 135060 : if (sjinfo->jointype == JOIN_SEMI)
413 : {
414 10718 : if (bms_is_subset(sjinfo->syn_righthand, rel1->relids) &&
415 1552 : !bms_equal(sjinfo->syn_righthand, rel1->relids))
416 618 : continue;
417 10100 : if (bms_is_subset(sjinfo->syn_righthand, rel2->relids) &&
418 7030 : !bms_equal(sjinfo->syn_righthand, rel2->relids))
419 214 : continue;
420 : }
421 :
422 : /*
423 : * If one input contains min_lefthand and the other contains
424 : * min_righthand, then we can perform the SJ at this join.
425 : *
426 : * Reject if we get matches to more than one SJ; that implies we're
427 : * considering something that's not really valid.
428 : */
429 248088 : if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) &&
430 113860 : bms_is_subset(sjinfo->min_righthand, rel2->relids))
431 : {
432 107244 : if (match_sjinfo)
433 9222 : return false; /* invalid join path */
434 107244 : match_sjinfo = sjinfo;
435 107244 : reversed = false;
436 : }
437 36722 : else if (bms_is_subset(sjinfo->min_lefthand, rel2->relids) &&
438 9738 : bms_is_subset(sjinfo->min_righthand, rel1->relids))
439 : {
440 8514 : if (match_sjinfo)
441 0 : return false; /* invalid join path */
442 8514 : match_sjinfo = sjinfo;
443 8514 : reversed = true;
444 : }
445 21462 : else if (sjinfo->jointype == JOIN_SEMI &&
446 3558 : bms_equal(sjinfo->syn_righthand, rel2->relids) &&
447 566 : create_unique_path(root, rel2, rel2->cheapest_total_path,
448 : 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 : */
472 560 : if (match_sjinfo)
473 84 : return false; /* invalid join path */
474 476 : match_sjinfo = sjinfo;
475 476 : reversed = false;
476 476 : unique_ified = true;
477 : }
478 20342 : else if (sjinfo->jointype == JOIN_SEMI &&
479 2722 : bms_equal(sjinfo->syn_righthand, rel1->relids) &&
480 290 : create_unique_path(root, rel1, rel1->cheapest_total_path,
481 : sjinfo) != NULL)
482 : {
483 : /* Reversed semijoin case */
484 290 : if (match_sjinfo)
485 78 : return false; /* invalid join path */
486 212 : match_sjinfo = sjinfo;
487 212 : reversed = true;
488 212 : unique_ified = true;
489 : }
490 : else
491 : {
492 : /*
493 : * Otherwise, the proposed join overlaps the RHS but isn't a valid
494 : * implementation of this SJ. But don't panic quite yet: the RHS
495 : * violation might have occurred previously, in one or both input
496 : * relations, in which case we must have previously decided that
497 : * it was OK to commute some other SJ with this one. If we need
498 : * to perform this join to finish building up the RHS, rejecting
499 : * it could lead to not finding any plan at all. (This can occur
500 : * because of the heuristics elsewhere in this file that postpone
501 : * clauseless joins: we might not consider doing a clauseless join
502 : * within the RHS until after we've performed other, validly
503 : * commutable SJs with one or both sides of the clauseless join.)
504 : * This consideration boils down to the rule that if both inputs
505 : * overlap the RHS, we can allow the join --- they are either
506 : * fully within the RHS, or represent previously-allowed joins to
507 : * rels outside it.
508 : */
509 25978 : if (bms_overlap(rel1->relids, sjinfo->min_righthand) &&
510 8358 : bms_overlap(rel2->relids, sjinfo->min_righthand))
511 174 : continue; /* assume valid previous violation of RHS */
512 :
513 : /*
514 : * The proposed join could still be legal, but only if we're
515 : * allowed to associate it into the RHS of this SJ. That means
516 : * this SJ must be a LEFT join (not SEMI or ANTI, and certainly
517 : * not FULL) and the proposed join must not overlap the LHS.
518 : */
519 32618 : if (sjinfo->jointype != JOIN_LEFT ||
520 15172 : bms_overlap(joinrelids, sjinfo->min_lefthand))
521 9060 : return false; /* invalid join path */
522 :
523 : /*
524 : * To be valid, the proposed join must be a LEFT join; otherwise
525 : * it can't associate into this SJ's RHS. But we may not yet have
526 : * found the SpecialJoinInfo matching the proposed join, so we
527 : * can't test that yet. Remember the requirement for later.
528 : */
529 8386 : must_be_leftjoin = true;
530 : }
531 : }
532 :
533 : /*
534 : * Fail if violated any SJ's RHS and didn't match to a LEFT SJ: the
535 : * proposed join can't associate into an SJ's RHS.
536 : *
537 : * Also, fail if the proposed join's predicate isn't strict; we're
538 : * essentially checking to see if we can apply outer-join identity 3, and
539 : * that's a requirement. (This check may be redundant with checks in
540 : * make_outerjoininfo, but I'm not quite sure, and it's cheap to test.)
541 : */
542 336352 : if (must_be_leftjoin &&
543 5398 : (match_sjinfo == NULL ||
544 5398 : match_sjinfo->jointype != JOIN_LEFT ||
545 5398 : !match_sjinfo->lhs_strict))
546 1512 : return false; /* invalid join path */
547 :
548 : /*
549 : * We also have to check for constraints imposed by LATERAL references.
550 : */
551 334840 : if (root->hasLateralRTEs)
552 : {
553 : bool lateral_fwd;
554 : bool lateral_rev;
555 : Relids join_lateral_rels;
556 :
557 : /*
558 : * The proposed rels could each contain lateral references to the
559 : * other, in which case the join is impossible. If there are lateral
560 : * references in just one direction, then the join has to be done with
561 : * a nestloop with the lateral referencer on the inside. If the join
562 : * matches an SJ that cannot be implemented by such a nestloop, the
563 : * join is impossible.
564 : *
565 : * Also, if the lateral reference is only indirect, we should reject
566 : * the join; whatever rel(s) the reference chain goes through must be
567 : * joined to first.
568 : */
569 17382 : lateral_fwd = bms_overlap(rel1->relids, rel2->lateral_relids);
570 17382 : lateral_rev = bms_overlap(rel2->relids, rel1->lateral_relids);
571 17382 : if (lateral_fwd && lateral_rev)
572 18 : return false; /* have lateral refs in both directions */
573 17364 : if (lateral_fwd)
574 : {
575 : /* has to be implemented as nestloop with rel1 on left */
576 10420 : if (match_sjinfo &&
577 408 : (reversed ||
578 390 : unique_ified ||
579 390 : match_sjinfo->jointype == JOIN_FULL))
580 18 : return false; /* not implementable as nestloop */
581 : /* check there is a direct reference from rel2 to rel1 */
582 10402 : if (!bms_overlap(rel1->relids, rel2->direct_lateral_relids))
583 42 : return false; /* only indirect refs, so reject */
584 : }
585 6944 : else if (lateral_rev)
586 : {
587 : /* has to be implemented as nestloop with rel2 on left */
588 1472 : if (match_sjinfo &&
589 72 : (!reversed ||
590 72 : unique_ified ||
591 72 : match_sjinfo->jointype == JOIN_FULL))
592 0 : return false; /* not implementable as nestloop */
593 : /* check there is a direct reference from rel1 to rel2 */
594 1472 : if (!bms_overlap(rel2->relids, rel1->direct_lateral_relids))
595 0 : return false; /* only indirect refs, so reject */
596 : }
597 :
598 : /*
599 : * LATERAL references could also cause problems later on if we accept
600 : * this join: if the join's minimum parameterization includes any rels
601 : * that would have to be on the inside of an outer join with this join
602 : * rel, then it's never going to be possible to build the complete
603 : * query using this join. We should reject this join not only because
604 : * it'll save work, but because if we don't, the clauseless-join
605 : * heuristics might think that legality of this join means that some
606 : * other join rel need not be formed, and that could lead to failure
607 : * to find any plan at all. We have to consider not only rels that
608 : * are directly on the inner side of an OJ with the joinrel, but also
609 : * ones that are indirectly so, so search to find all such rels.
610 : */
611 17304 : join_lateral_rels = min_join_parameterization(root, joinrelids,
612 : rel1, rel2);
613 17304 : if (join_lateral_rels)
614 : {
615 2148 : Relids join_plus_rhs = bms_copy(joinrelids);
616 : bool more;
617 :
618 : do
619 : {
620 2544 : more = false;
621 4458 : foreach(l, root->join_info_list)
622 : {
623 1914 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
624 :
625 : /* ignore full joins --- their ordering is predetermined */
626 1914 : if (sjinfo->jointype == JOIN_FULL)
627 18 : continue;
628 :
629 1896 : if (bms_overlap(sjinfo->min_lefthand, join_plus_rhs) &&
630 1596 : !bms_is_subset(sjinfo->min_righthand, join_plus_rhs))
631 : {
632 546 : join_plus_rhs = bms_add_members(join_plus_rhs,
633 546 : sjinfo->min_righthand);
634 546 : more = true;
635 : }
636 : }
637 2544 : } while (more);
638 2148 : if (bms_overlap(join_plus_rhs, join_lateral_rels))
639 312 : return false; /* will not be able to join to some RHS rel */
640 : }
641 : }
642 :
643 : /* Otherwise, it's a valid join */
644 334450 : *sjinfo_p = match_sjinfo;
645 334450 : *reversed_p = reversed;
646 334450 : return true;
647 : }
648 :
649 : /*
650 : * init_dummy_sjinfo
651 : * Populate the given SpecialJoinInfo for a plain inner join between the
652 : * left and right relations specified by left_relids and right_relids
653 : * respectively.
654 : *
655 : * Normally, an inner join does not have a SpecialJoinInfo node associated with
656 : * it. But some functions involved in join planning require one containing at
657 : * least the information of which relations are being joined. So we initialize
658 : * that information here.
659 : */
660 : void
661 935670 : init_dummy_sjinfo(SpecialJoinInfo *sjinfo, Relids left_relids,
662 : Relids right_relids)
663 : {
664 935670 : sjinfo->type = T_SpecialJoinInfo;
665 935670 : sjinfo->min_lefthand = left_relids;
666 935670 : sjinfo->min_righthand = right_relids;
667 935670 : sjinfo->syn_lefthand = left_relids;
668 935670 : sjinfo->syn_righthand = right_relids;
669 935670 : sjinfo->jointype = JOIN_INNER;
670 935670 : sjinfo->ojrelid = 0;
671 935670 : sjinfo->commute_above_l = NULL;
672 935670 : sjinfo->commute_above_r = NULL;
673 935670 : sjinfo->commute_below_l = NULL;
674 935670 : sjinfo->commute_below_r = NULL;
675 : /* we don't bother trying to make the remaining fields valid */
676 935670 : sjinfo->lhs_strict = false;
677 935670 : sjinfo->semi_can_btree = false;
678 935670 : sjinfo->semi_can_hash = false;
679 935670 : sjinfo->semi_operators = NIL;
680 935670 : sjinfo->semi_rhs_exprs = NIL;
681 935670 : }
682 :
683 : /*
684 : * make_join_rel
685 : * Find or create a join RelOptInfo that represents the join of
686 : * the two given rels, and add to it path information for paths
687 : * created with the two rels as outer and inner rel.
688 : * (The join rel may already contain paths generated from other
689 : * pairs of rels that add up to the same set of base rels.)
690 : *
691 : * NB: will return NULL if attempted join is not valid. This can happen
692 : * when working with outer joins, or with IN or EXISTS clauses that have been
693 : * turned into joins.
694 : */
695 : RelOptInfo *
696 345184 : make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
697 : {
698 : Relids joinrelids;
699 : SpecialJoinInfo *sjinfo;
700 : bool reversed;
701 345184 : List *pushed_down_joins = NIL;
702 : SpecialJoinInfo sjinfo_data;
703 : RelOptInfo *joinrel;
704 : List *restrictlist;
705 :
706 : /* We should never try to join two overlapping sets of rels. */
707 : Assert(!bms_overlap(rel1->relids, rel2->relids));
708 :
709 : /* Construct Relids set that identifies the joinrel (without OJ as yet). */
710 345184 : joinrelids = bms_union(rel1->relids, rel2->relids);
711 :
712 : /* Check validity and determine join type. */
713 345184 : if (!join_is_legal(root, rel1, rel2, joinrelids,
714 : &sjinfo, &reversed))
715 : {
716 : /* invalid join path */
717 10968 : bms_free(joinrelids);
718 10968 : return NULL;
719 : }
720 :
721 : /*
722 : * Add outer join relid(s) to form the canonical relids. Any added outer
723 : * joins besides sjinfo itself are appended to pushed_down_joins.
724 : */
725 334216 : joinrelids = add_outer_joins_to_relids(root, joinrelids, sjinfo,
726 : &pushed_down_joins);
727 :
728 : /* Swap rels if needed to match the join info. */
729 334216 : if (reversed)
730 : {
731 8570 : RelOptInfo *trel = rel1;
732 :
733 8570 : rel1 = rel2;
734 8570 : rel2 = trel;
735 : }
736 :
737 : /*
738 : * If it's a plain inner join, then we won't have found anything in
739 : * join_info_list. Make up a SpecialJoinInfo so that selectivity
740 : * estimation functions will know what's being joined.
741 : */
742 334216 : if (sjinfo == NULL)
743 : {
744 218334 : sjinfo = &sjinfo_data;
745 218334 : init_dummy_sjinfo(sjinfo, rel1->relids, rel2->relids);
746 : }
747 :
748 : /*
749 : * Find or build the join RelOptInfo, and compute the restrictlist that
750 : * goes with this particular joining.
751 : */
752 334216 : joinrel = build_join_rel(root, joinrelids, rel1, rel2,
753 : sjinfo, pushed_down_joins,
754 : &restrictlist);
755 :
756 : /*
757 : * If we've already proven this join is empty, we needn't consider any
758 : * more paths for it.
759 : */
760 334216 : if (is_dummy_rel(joinrel))
761 : {
762 456 : bms_free(joinrelids);
763 456 : return joinrel;
764 : }
765 :
766 : /* Add paths to the join relation. */
767 333760 : populate_joinrel_with_paths(root, rel1, rel2, joinrel, sjinfo,
768 : restrictlist);
769 :
770 333760 : bms_free(joinrelids);
771 :
772 333760 : return joinrel;
773 : }
774 :
775 : /*
776 : * add_outer_joins_to_relids
777 : * Add relids to input_relids to represent any outer joins that will be
778 : * calculated at this join.
779 : *
780 : * input_relids is the union of the relid sets of the two input relations.
781 : * Note that we modify this in-place and return it; caller must bms_copy()
782 : * it first, if a separate value is desired.
783 : *
784 : * sjinfo represents the join being performed.
785 : *
786 : * If the current join completes the calculation of any outer joins that
787 : * have been pushed down per outer-join identity 3, those relids will be
788 : * added to the result along with sjinfo's own relid. If pushed_down_joins
789 : * is not NULL, then also the SpecialJoinInfos for such added outer joins will
790 : * be appended to *pushed_down_joins (so caller must initialize it to NIL).
791 : */
792 : Relids
793 341634 : add_outer_joins_to_relids(PlannerInfo *root, Relids input_relids,
794 : SpecialJoinInfo *sjinfo,
795 : List **pushed_down_joins)
796 : {
797 : /* Nothing to do if this isn't an outer join with an assigned relid. */
798 341634 : if (sjinfo == NULL || sjinfo->ojrelid == 0)
799 236918 : return input_relids;
800 :
801 : /*
802 : * If it's not a left join, we have no rules that would permit executing
803 : * it in non-syntactic order, so just form the syntactic relid set. (This
804 : * is just a quick-exit test; we'd come to the same conclusion anyway,
805 : * since its commute_below_l and commute_above_l sets must be empty.)
806 : */
807 104716 : if (sjinfo->jointype != JOIN_LEFT)
808 2278 : return bms_add_member(input_relids, sjinfo->ojrelid);
809 :
810 : /*
811 : * We cannot add the OJ relid if this join has been pushed into the RHS of
812 : * a syntactically-lower left join per OJ identity 3. (If it has, then we
813 : * cannot claim that its outputs represent the final state of its RHS.)
814 : * There will not be any other OJs that can be added either, so we're
815 : * done.
816 : */
817 102438 : if (!bms_is_subset(sjinfo->commute_below_l, input_relids))
818 5098 : return input_relids;
819 :
820 : /* OK to add OJ's own relid */
821 97340 : input_relids = bms_add_member(input_relids, sjinfo->ojrelid);
822 :
823 : /*
824 : * Contrariwise, if we are now forming the final result of such a commuted
825 : * pair of OJs, it's time to add the relid(s) of the pushed-down join(s).
826 : * We can skip this if this join was never a candidate to be pushed up.
827 : */
828 97340 : if (sjinfo->commute_above_l)
829 : {
830 18608 : Relids commute_above_rels = bms_copy(sjinfo->commute_above_l);
831 : ListCell *lc;
832 :
833 : /*
834 : * The current join could complete the nulling of more than one
835 : * pushed-down join, so we have to examine all the SpecialJoinInfos.
836 : * Because join_info_list was built in bottom-up order, it's
837 : * sufficient to traverse it once: an ojrelid we add in one loop
838 : * iteration would not have affected decisions of earlier iterations.
839 : */
840 62812 : foreach(lc, root->join_info_list)
841 : {
842 44204 : SpecialJoinInfo *othersj = (SpecialJoinInfo *) lfirst(lc);
843 :
844 44204 : if (othersj == sjinfo ||
845 25596 : othersj->ojrelid == 0 || othersj->jointype != JOIN_LEFT)
846 18620 : continue; /* definitely not interesting */
847 :
848 25584 : if (!bms_is_member(othersj->ojrelid, commute_above_rels))
849 6828 : continue;
850 :
851 : /* Add it if not already present but conditions now satisfied */
852 37512 : if (!bms_is_member(othersj->ojrelid, input_relids) &&
853 37488 : bms_is_subset(othersj->min_lefthand, input_relids) &&
854 28186 : bms_is_subset(othersj->min_righthand, input_relids) &&
855 9454 : bms_is_subset(othersj->commute_below_l, input_relids))
856 : {
857 9418 : input_relids = bms_add_member(input_relids, othersj->ojrelid);
858 : /* report such pushed down outer joins, if asked */
859 9418 : if (pushed_down_joins != NULL)
860 9418 : *pushed_down_joins = lappend(*pushed_down_joins, othersj);
861 :
862 : /*
863 : * We must also check any joins that othersj potentially
864 : * commutes with. They likewise must appear later in
865 : * join_info_list than othersj itself, so we can visit them
866 : * later in this loop.
867 : */
868 9418 : commute_above_rels = bms_add_members(commute_above_rels,
869 9418 : othersj->commute_above_l);
870 : }
871 : }
872 : }
873 :
874 97340 : return input_relids;
875 : }
876 :
877 : /*
878 : * populate_joinrel_with_paths
879 : * Add paths to the given joinrel for given pair of joining relations. The
880 : * SpecialJoinInfo provides details about the join and the restrictlist
881 : * contains the join clauses and the other clauses applicable for given pair
882 : * of the joining relations.
883 : */
884 : static void
885 339198 : populate_joinrel_with_paths(PlannerInfo *root, RelOptInfo *rel1,
886 : RelOptInfo *rel2, RelOptInfo *joinrel,
887 : SpecialJoinInfo *sjinfo, List *restrictlist)
888 : {
889 : /*
890 : * Consider paths using each rel as both outer and inner. Depending on
891 : * the join type, a provably empty outer or inner rel might mean the join
892 : * is provably empty too; in which case throw away any previously computed
893 : * paths and mark the join as dummy. (We do it this way since it's
894 : * conceivable that dummy-ness of a multi-element join might only be
895 : * noticeable for certain construction paths.)
896 : *
897 : * Also, a provably constant-false join restriction typically means that
898 : * we can skip evaluating one or both sides of the join. We do this by
899 : * marking the appropriate rel as dummy. For outer joins, a
900 : * constant-false restriction that is pushed down still means the whole
901 : * join is dummy, while a non-pushed-down one means that no inner rows
902 : * will join so we can treat the inner rel as dummy.
903 : *
904 : * We need only consider the jointypes that appear in join_info_list, plus
905 : * JOIN_INNER.
906 : */
907 339198 : switch (sjinfo->jointype)
908 : {
909 220226 : case JOIN_INNER:
910 440434 : if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
911 220208 : restriction_is_constant_false(restrictlist, joinrel, false))
912 : {
913 198 : mark_dummy_rel(joinrel);
914 198 : break;
915 : }
916 220028 : add_paths_to_joinrel(root, joinrel, rel1, rel2,
917 : JOIN_INNER, sjinfo,
918 : restrictlist);
919 220028 : add_paths_to_joinrel(root, joinrel, rel2, rel1,
920 : JOIN_INNER, sjinfo,
921 : restrictlist);
922 220028 : break;
923 104116 : case JOIN_LEFT:
924 208178 : if (is_dummy_rel(rel1) ||
925 104062 : restriction_is_constant_false(restrictlist, joinrel, true))
926 : {
927 86 : mark_dummy_rel(joinrel);
928 86 : break;
929 : }
930 104222 : if (restriction_is_constant_false(restrictlist, joinrel, false) &&
931 192 : bms_is_subset(rel2->relids, sjinfo->syn_righthand))
932 168 : mark_dummy_rel(rel2);
933 104030 : add_paths_to_joinrel(root, joinrel, rel1, rel2,
934 : JOIN_LEFT, sjinfo,
935 : restrictlist);
936 104030 : add_paths_to_joinrel(root, joinrel, rel2, rel1,
937 : JOIN_RIGHT, sjinfo,
938 : restrictlist);
939 104030 : break;
940 1732 : case JOIN_FULL:
941 3464 : if ((is_dummy_rel(rel1) && is_dummy_rel(rel2)) ||
942 1732 : restriction_is_constant_false(restrictlist, joinrel, true))
943 : {
944 12 : mark_dummy_rel(joinrel);
945 12 : break;
946 : }
947 1720 : add_paths_to_joinrel(root, joinrel, rel1, rel2,
948 : JOIN_FULL, sjinfo,
949 : restrictlist);
950 1720 : add_paths_to_joinrel(root, joinrel, rel2, rel1,
951 : JOIN_FULL, sjinfo,
952 : restrictlist);
953 :
954 : /*
955 : * If there are join quals that aren't mergeable or hashable, we
956 : * may not be able to build any valid plan. Complain here so that
957 : * we can give a somewhat-useful error message. (Since we have no
958 : * flexibility of planning for a full join, there's no chance of
959 : * succeeding later with another pair of input rels.)
960 : */
961 1720 : if (joinrel->pathlist == NIL)
962 0 : ereport(ERROR,
963 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
964 : errmsg("FULL JOIN is only supported with merge-joinable or hash-joinable join conditions")));
965 1720 : break;
966 7648 : case JOIN_SEMI:
967 :
968 : /*
969 : * We might have a normal semijoin, or a case where we don't have
970 : * enough rels to do the semijoin but can unique-ify the RHS and
971 : * then do an innerjoin (see comments in join_is_legal). In the
972 : * latter case we can't apply JOIN_SEMI joining.
973 : */
974 14974 : if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) &&
975 7326 : bms_is_subset(sjinfo->min_righthand, rel2->relids))
976 : {
977 14646 : if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
978 7320 : restriction_is_constant_false(restrictlist, joinrel, false))
979 : {
980 12 : mark_dummy_rel(joinrel);
981 12 : break;
982 : }
983 7314 : add_paths_to_joinrel(root, joinrel, rel1, rel2,
984 : JOIN_SEMI, sjinfo,
985 : restrictlist);
986 7314 : add_paths_to_joinrel(root, joinrel, rel2, rel1,
987 : JOIN_RIGHT_SEMI, sjinfo,
988 : restrictlist);
989 : }
990 :
991 : /*
992 : * If we know how to unique-ify the RHS and one input rel is
993 : * exactly the RHS (not a superset) we can consider unique-ifying
994 : * it and then doing a regular join. (The create_unique_path
995 : * check here is probably redundant with what join_is_legal did,
996 : * but if so the check is cheap because it's cached. So test
997 : * anyway to be sure.)
998 : */
999 15272 : if (bms_equal(sjinfo->syn_righthand, rel2->relids) &&
1000 7636 : create_unique_path(root, rel2, rel2->cheapest_total_path,
1001 : sjinfo) != NULL)
1002 : {
1003 15044 : if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
1004 7522 : restriction_is_constant_false(restrictlist, joinrel, false))
1005 : {
1006 0 : mark_dummy_rel(joinrel);
1007 0 : break;
1008 : }
1009 7522 : add_paths_to_joinrel(root, joinrel, rel1, rel2,
1010 : JOIN_UNIQUE_INNER, sjinfo,
1011 : restrictlist);
1012 7522 : add_paths_to_joinrel(root, joinrel, rel2, rel1,
1013 : JOIN_UNIQUE_OUTER, sjinfo,
1014 : restrictlist);
1015 : }
1016 7636 : break;
1017 5476 : case JOIN_ANTI:
1018 10952 : if (is_dummy_rel(rel1) ||
1019 5476 : restriction_is_constant_false(restrictlist, joinrel, true))
1020 : {
1021 0 : mark_dummy_rel(joinrel);
1022 0 : break;
1023 : }
1024 5476 : 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 5476 : add_paths_to_joinrel(root, joinrel, rel1, rel2,
1028 : JOIN_ANTI, sjinfo,
1029 : restrictlist);
1030 5476 : add_paths_to_joinrel(root, joinrel, rel2, rel1,
1031 : JOIN_RIGHT_ANTI, sjinfo,
1032 : restrictlist);
1033 5476 : 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 339198 : try_partitionwise_join(root, rel1, rel2, joinrel, sjinfo, restrictlist);
1042 339198 : }
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 81500 : have_join_order_restriction(PlannerInfo *root,
1067 : RelOptInfo *rel1, RelOptInfo *rel2)
1068 : {
1069 81500 : 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 153402 : if (bms_overlap(rel1->relids, rel2->direct_lateral_relids) ||
1077 71902 : bms_overlap(rel2->relids, rel1->direct_lateral_relids))
1078 10542 : 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 72804 : foreach(l, root->placeholder_list)
1088 : {
1089 1900 : PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(l);
1090 :
1091 2284 : if (bms_is_subset(rel1->relids, phinfo->ph_eval_at) &&
1092 384 : bms_is_subset(rel2->relids, phinfo->ph_eval_at))
1093 54 : 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 190872 : foreach(l, root->join_info_list)
1105 : {
1106 121414 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
1107 :
1108 : /* ignore full joins --- other mechanisms handle them */
1109 121414 : if (sjinfo->jointype == JOIN_FULL)
1110 42 : continue;
1111 :
1112 : /* Can we perform the SJ with these rels? */
1113 148150 : if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) &&
1114 26778 : bms_is_subset(sjinfo->min_righthand, rel2->relids))
1115 : {
1116 1086 : result = true;
1117 1086 : break;
1118 : }
1119 127430 : if (bms_is_subset(sjinfo->min_lefthand, rel2->relids) &&
1120 7144 : 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 144638 : if (bms_overlap(sjinfo->min_righthand, rel1->relids) &&
1132 24562 : bms_overlap(sjinfo->min_righthand, rel2->relids))
1133 : {
1134 120 : result = true;
1135 120 : break;
1136 : }
1137 :
1138 : /* Likewise for the LHS. */
1139 148584 : if (bms_overlap(sjinfo->min_lefthand, rel1->relids) &&
1140 28628 : bms_overlap(sjinfo->min_lefthand, rel2->relids))
1141 : {
1142 30 : result = true;
1143 30 : 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 70904 : if (result)
1157 : {
1158 2772 : if (has_legal_joinclause(root, rel1) ||
1159 1326 : has_legal_joinclause(root, rel2))
1160 234 : result = false;
1161 : }
1162 :
1163 70904 : 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 30846 : has_join_restriction(PlannerInfo *root, RelOptInfo *rel)
1180 : {
1181 : ListCell *l;
1182 :
1183 30846 : if (rel->lateral_relids != NULL || rel->lateral_referencers != NULL)
1184 18028 : return true;
1185 :
1186 13568 : foreach(l, root->placeholder_list)
1187 : {
1188 798 : PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(l);
1189 :
1190 798 : if (bms_is_subset(rel->relids, phinfo->ph_eval_at) &&
1191 174 : !bms_equal(rel->relids, phinfo->ph_eval_at))
1192 48 : return true;
1193 : }
1194 :
1195 13564 : foreach(l, root->join_info_list)
1196 : {
1197 2966 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
1198 :
1199 : /* ignore full joins --- other mechanisms preserve their ordering */
1200 2966 : if (sjinfo->jointype == JOIN_FULL)
1201 86 : continue;
1202 :
1203 : /* ignore if SJ is already contained in rel */
1204 4440 : if (bms_is_subset(sjinfo->min_lefthand, rel->relids) &&
1205 1560 : 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 3804 : if (bms_overlap(sjinfo->min_lefthand, rel->relids) ||
1210 1296 : bms_overlap(sjinfo->min_righthand, rel->relids))
1211 2172 : return true;
1212 : }
1213 :
1214 10598 : 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 2772 : has_legal_joinclause(PlannerInfo *root, RelOptInfo *rel)
1236 : {
1237 : ListCell *lc;
1238 :
1239 10224 : foreach(lc, root->initial_rels)
1240 : {
1241 7686 : RelOptInfo *rel2 = (RelOptInfo *) lfirst(lc);
1242 :
1243 : /* ignore rels that are already in "rel" */
1244 7686 : if (bms_overlap(rel->relids, rel2->relids))
1245 3276 : continue;
1246 :
1247 4410 : 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 390 : joinrelids = bms_union(rel->relids, rel2->relids);
1255 :
1256 390 : if (join_is_legal(root, rel, rel2, joinrelids,
1257 : &sjinfo, &reversed))
1258 : {
1259 : /* Yes, this will work */
1260 234 : bms_free(joinrelids);
1261 234 : return true;
1262 : }
1263 :
1264 156 : bms_free(joinrelids);
1265 : }
1266 : }
1267 :
1268 2538 : return false;
1269 : }
1270 :
1271 :
1272 : /*
1273 : * is_dummy_rel --- has relation been proven empty?
1274 : */
1275 : bool
1276 2620596 : 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 2620596 : if (rel->pathlist == NIL)
1286 1400632 : return false;
1287 1219964 : 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 1263934 : if (IsA(path, ProjectionPath))
1298 34914 : path = ((ProjectionPath *) path)->subpath;
1299 1229020 : else if (IsA(path, ProjectSetPath))
1300 9056 : path = ((ProjectSetPath *) path)->subpath;
1301 : else
1302 1219964 : break;
1303 : }
1304 1219964 : if (IS_DUMMY_APPEND(path))
1305 4130 : return true;
1306 1215834 : 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 566 : mark_dummy_rel(RelOptInfo *rel)
1326 : {
1327 : MemoryContext oldcontext;
1328 :
1329 : /* Already marked? */
1330 566 : if (is_dummy_rel(rel))
1331 12 : return;
1332 :
1333 : /* No, so choose correct context to make the dummy path in */
1334 554 : oldcontext = MemoryContextSwitchTo(GetMemoryChunkContext(rel));
1335 :
1336 : /* Set dummy size estimate */
1337 554 : rel->rows = 0;
1338 :
1339 : /* Evict any previously chosen paths */
1340 554 : rel->pathlist = NIL;
1341 554 : rel->partial_pathlist = NIL;
1342 :
1343 : /* Set up the dummy path */
1344 554 : 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 554 : set_cheapest(rel);
1350 :
1351 554 : 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 455826 : 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 978858 : foreach(lc, restrictlist)
1381 : {
1382 523454 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
1383 :
1384 523454 : if (only_pushed_down && !RINFO_IS_PUSHED_DOWN(rinfo, joinrel->relids))
1385 141496 : continue;
1386 :
1387 381958 : if (rinfo->clause && IsA(rinfo->clause, Const))
1388 : {
1389 5362 : Const *con = (Const *) rinfo->clause;
1390 :
1391 : /* constant NULL is as good as constant FALSE for our purposes */
1392 5362 : if (con->constisnull)
1393 422 : return true;
1394 5254 : if (!DatumGetBool(con->constvalue))
1395 314 : return true;
1396 : }
1397 : }
1398 455404 : 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 339198 : try_partitionwise_join(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2,
1423 : RelOptInfo *joinrel, SpecialJoinInfo *parent_sjinfo,
1424 : List *parent_restrictlist)
1425 : {
1426 339198 : bool rel1_is_simple = IS_SIMPLE_REL(rel1);
1427 339198 : bool rel2_is_simple = IS_SIMPLE_REL(rel2);
1428 339198 : List *parts1 = NIL;
1429 339198 : List *parts2 = NIL;
1430 339198 : ListCell *lcr1 = NULL;
1431 339198 : ListCell *lcr2 = NULL;
1432 : int cnt_parts;
1433 :
1434 : /* Guard against stack overflow due to overly deep partition hierarchy. */
1435 339198 : check_stack_depth();
1436 :
1437 : /* Nothing to do, if the join relation is not partitioned. */
1438 339198 : if (joinrel->part_scheme == NULL || joinrel->nparts == 0)
1439 337132 : 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 2204 : 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 2186 : compute_partition_bounds(root, rel1, rel2, joinrel, parent_sjinfo,
1467 : &parts1, &parts2);
1468 :
1469 2186 : 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 7688 : 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 5622 : 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 3612 : child_rel1 = rel1->part_rels[cnt_parts];
1503 3612 : child_rel2 = rel2->part_rels[cnt_parts];
1504 : }
1505 :
1506 5622 : rel1_empty = (child_rel1 == NULL || IS_DUMMY_REL(child_rel1));
1507 5622 : 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 5622 : switch (parent_sjinfo->jointype)
1517 : {
1518 2804 : case JOIN_INNER:
1519 : case JOIN_SEMI:
1520 2804 : if (rel1_empty || rel2_empty)
1521 64 : continue; /* ignore this join segment */
1522 2768 : 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 5558 : 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 5438 : 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 5438 : 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 5438 : child_sjinfo = build_child_join_sjinfo(root, parent_sjinfo,
1583 : child_rel1->relids,
1584 : child_rel2->relids);
1585 :
1586 : /* Find the AppendRelInfo structures */
1587 5438 : child_relids = bms_union(child_rel1->relids, child_rel2->relids);
1588 5438 : 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 5438 : (List *) adjust_appendrel_attrs(root,
1597 : (Node *) parent_restrictlist,
1598 : nappinfos, appinfos);
1599 :
1600 : /* Find or construct the child join's RelOptInfo */
1601 5438 : child_joinrel = joinrel->part_rels[cnt_parts];
1602 5438 : if (!child_joinrel)
1603 : {
1604 4930 : child_joinrel = build_child_join_rel(root, child_rel1, child_rel2,
1605 : joinrel, child_restrictlist,
1606 : child_sjinfo, nappinfos, appinfos);
1607 4930 : joinrel->part_rels[cnt_parts] = child_joinrel;
1608 4930 : joinrel->live_parts = bms_add_member(joinrel->live_parts, cnt_parts);
1609 4930 : joinrel->all_partrels = bms_add_members(joinrel->all_partrels,
1610 4930 : 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 5438 : 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 5438 : pfree(appinfos);
1630 5438 : bms_free(child_relids);
1631 5438 : 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 5438 : build_child_join_sjinfo(PlannerInfo *root, SpecialJoinInfo *parent_sjinfo,
1645 : Relids left_relids, Relids right_relids)
1646 : {
1647 5438 : 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 5438 : if (parent_sjinfo->jointype == JOIN_INNER)
1655 : {
1656 : Assert(parent_sjinfo->ojrelid == 0);
1657 2318 : init_dummy_sjinfo(sjinfo, left_relids, right_relids);
1658 2318 : return sjinfo;
1659 : }
1660 :
1661 3120 : memcpy(sjinfo, parent_sjinfo, sizeof(SpecialJoinInfo));
1662 3120 : left_appinfos = find_appinfos_by_relids(root, left_relids,
1663 : &left_nappinfos);
1664 3120 : right_appinfos = find_appinfos_by_relids(root, right_relids,
1665 : &right_nappinfos);
1666 :
1667 3120 : sjinfo->min_lefthand = adjust_child_relids(sjinfo->min_lefthand,
1668 : left_nappinfos, left_appinfos);
1669 3120 : sjinfo->min_righthand = adjust_child_relids(sjinfo->min_righthand,
1670 : right_nappinfos,
1671 : right_appinfos);
1672 3120 : sjinfo->syn_lefthand = adjust_child_relids(sjinfo->syn_lefthand,
1673 : left_nappinfos, left_appinfos);
1674 3120 : sjinfo->syn_righthand = adjust_child_relids(sjinfo->syn_righthand,
1675 : right_nappinfos,
1676 : right_appinfos);
1677 : /* outer-join relids need no adjustment */
1678 6240 : sjinfo->semi_rhs_exprs = (List *) adjust_appendrel_attrs(root,
1679 3120 : (Node *) sjinfo->semi_rhs_exprs,
1680 : right_nappinfos,
1681 : right_appinfos);
1682 :
1683 3120 : pfree(left_appinfos);
1684 3120 : pfree(right_appinfos);
1685 :
1686 3120 : 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 5438 : 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 5438 : if (child_sjinfo->jointype != JOIN_INNER)
1706 : {
1707 3120 : if (child_sjinfo->min_lefthand != parent_sjinfo->min_lefthand)
1708 3102 : bms_free(child_sjinfo->min_lefthand);
1709 :
1710 3120 : if (child_sjinfo->min_righthand != parent_sjinfo->min_righthand)
1711 3120 : bms_free(child_sjinfo->min_righthand);
1712 :
1713 3120 : if (child_sjinfo->syn_lefthand != parent_sjinfo->syn_lefthand)
1714 3120 : bms_free(child_sjinfo->syn_lefthand);
1715 :
1716 3120 : if (child_sjinfo->syn_righthand != parent_sjinfo->syn_righthand)
1717 3120 : 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 5438 : pfree(child_sjinfo);
1733 5438 : }
1734 :
1735 : /*
1736 : * compute_partition_bounds
1737 : * Compute the partition bounds for a join rel from those for inputs
1738 : */
1739 : static void
1740 2186 : 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 2186 : if (joinrel->nparts == -1)
1750 : {
1751 2010 : PartitionScheme part_scheme = joinrel->part_scheme;
1752 2010 : PartitionBoundInfo boundinfo = NULL;
1753 2010 : 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 2010 : if (!rel1->partbounds_merged &&
1769 1950 : !rel2->partbounds_merged &&
1770 3642 : rel1->nparts == rel2->nparts &&
1771 1692 : partition_bounds_equal(part_scheme->partnatts,
1772 : part_scheme->parttyplen,
1773 : part_scheme->parttypbyval,
1774 : rel1->boundinfo, rel2->boundinfo))
1775 : {
1776 1164 : boundinfo = rel1->boundinfo;
1777 1164 : 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 1896 : joinrel->boundinfo = boundinfo;
1799 1896 : joinrel->nparts = nparts;
1800 1896 : joinrel->part_rels =
1801 1896 : (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 176 : 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 : }
|
