Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * joinpath.c
4 : * Routines to find all possible paths for processing a set of joins
5 : *
6 : * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : *
10 : * IDENTIFICATION
11 : * src/backend/optimizer/path/joinpath.c
12 : *
13 : *-------------------------------------------------------------------------
14 : */
15 : #include "postgres.h"
16 :
17 : #include <math.h>
18 :
19 : #include "executor/executor.h"
20 : #include "foreign/fdwapi.h"
21 : #include "nodes/nodeFuncs.h"
22 : #include "optimizer/cost.h"
23 : #include "optimizer/optimizer.h"
24 : #include "optimizer/pathnode.h"
25 : #include "optimizer/paths.h"
26 : #include "optimizer/planmain.h"
27 : #include "utils/typcache.h"
28 :
29 : /* Hook for plugins to get control in add_paths_to_joinrel() */
30 : set_join_pathlist_hook_type set_join_pathlist_hook = NULL;
31 :
32 : /*
33 : * Paths parameterized by a parent rel can be considered to be parameterized
34 : * by any of its children, when we are performing partitionwise joins. These
35 : * macros simplify checking for such cases. Beware multiple eval of args.
36 : */
37 : #define PATH_PARAM_BY_PARENT(path, rel) \
38 : ((path)->param_info && bms_overlap(PATH_REQ_OUTER(path), \
39 : (rel)->top_parent_relids))
40 : #define PATH_PARAM_BY_REL_SELF(path, rel) \
41 : ((path)->param_info && bms_overlap(PATH_REQ_OUTER(path), (rel)->relids))
42 :
43 : #define PATH_PARAM_BY_REL(path, rel) \
44 : (PATH_PARAM_BY_REL_SELF(path, rel) || PATH_PARAM_BY_PARENT(path, rel))
45 :
46 : static void try_partial_mergejoin_path(PlannerInfo *root,
47 : RelOptInfo *joinrel,
48 : Path *outer_path,
49 : Path *inner_path,
50 : List *pathkeys,
51 : List *mergeclauses,
52 : List *outersortkeys,
53 : List *innersortkeys,
54 : JoinType jointype,
55 : JoinPathExtraData *extra);
56 : static void sort_inner_and_outer(PlannerInfo *root, RelOptInfo *joinrel,
57 : RelOptInfo *outerrel, RelOptInfo *innerrel,
58 : JoinType jointype, JoinPathExtraData *extra);
59 : static inline bool clause_sides_match_join(RestrictInfo *rinfo,
60 : RelOptInfo *outerrel,
61 : RelOptInfo *innerrel);
62 : static void match_unsorted_outer(PlannerInfo *root, RelOptInfo *joinrel,
63 : RelOptInfo *outerrel, RelOptInfo *innerrel,
64 : JoinType jointype, JoinPathExtraData *extra);
65 : static void consider_parallel_nestloop(PlannerInfo *root,
66 : RelOptInfo *joinrel,
67 : RelOptInfo *outerrel,
68 : RelOptInfo *innerrel,
69 : JoinType jointype,
70 : JoinPathExtraData *extra);
71 : static void consider_parallel_mergejoin(PlannerInfo *root,
72 : RelOptInfo *joinrel,
73 : RelOptInfo *outerrel,
74 : RelOptInfo *innerrel,
75 : JoinType jointype,
76 : JoinPathExtraData *extra,
77 : Path *inner_cheapest_total);
78 : static void hash_inner_and_outer(PlannerInfo *root, RelOptInfo *joinrel,
79 : RelOptInfo *outerrel, RelOptInfo *innerrel,
80 : JoinType jointype, JoinPathExtraData *extra);
81 : static List *select_mergejoin_clauses(PlannerInfo *root,
82 : RelOptInfo *joinrel,
83 : RelOptInfo *outerrel,
84 : RelOptInfo *innerrel,
85 : List *restrictlist,
86 : JoinType jointype,
87 : bool *mergejoin_allowed);
88 : static void generate_mergejoin_paths(PlannerInfo *root,
89 : RelOptInfo *joinrel,
90 : RelOptInfo *innerrel,
91 : Path *outerpath,
92 : JoinType jointype,
93 : JoinPathExtraData *extra,
94 : bool useallclauses,
95 : Path *inner_cheapest_total,
96 : List *merge_pathkeys,
97 : bool is_partial);
98 :
99 :
100 : /*
101 : * add_paths_to_joinrel
102 : * Given a join relation and two component rels from which it can be made,
103 : * consider all possible paths that use the two component rels as outer
104 : * and inner rel respectively. Add these paths to the join rel's pathlist
105 : * if they survive comparison with other paths (and remove any existing
106 : * paths that are dominated by these paths).
107 : *
108 : * Modifies the pathlist field of the joinrel node to contain the best
109 : * paths found so far.
110 : *
111 : * jointype is not necessarily the same as sjinfo->jointype; it might be
112 : * "flipped around" if we are considering joining the rels in the opposite
113 : * direction from what's indicated in sjinfo.
114 : *
115 : * Also, this routine and others in this module accept the special JoinTypes
116 : * JOIN_UNIQUE_OUTER and JOIN_UNIQUE_INNER to indicate that we should
117 : * unique-ify the outer or inner relation and then apply a regular inner
118 : * join. These values are not allowed to propagate outside this module,
119 : * however. Path cost estimation code may need to recognize that it's
120 : * dealing with such a case --- the combination of nominal jointype INNER
121 : * with sjinfo->jointype == JOIN_SEMI indicates that.
122 : */
123 : void
124 561878 : add_paths_to_joinrel(PlannerInfo *root,
125 : RelOptInfo *joinrel,
126 : RelOptInfo *outerrel,
127 : RelOptInfo *innerrel,
128 : JoinType jointype,
129 : SpecialJoinInfo *sjinfo,
130 : List *restrictlist)
131 : {
132 : JoinPathExtraData extra;
133 561878 : bool mergejoin_allowed = true;
134 : ListCell *lc;
135 : Relids joinrelids;
136 :
137 : /*
138 : * PlannerInfo doesn't contain the SpecialJoinInfos created for joins
139 : * between child relations, even if there is a SpecialJoinInfo node for
140 : * the join between the topmost parents. So, while calculating Relids set
141 : * representing the restriction, consider relids of topmost parent of
142 : * partitions.
143 : */
144 561878 : if (joinrel->reloptkind == RELOPT_OTHER_JOINREL)
145 10588 : joinrelids = joinrel->top_parent_relids;
146 : else
147 551290 : joinrelids = joinrel->relids;
148 :
149 561878 : extra.restrictlist = restrictlist;
150 561878 : extra.mergeclause_list = NIL;
151 561878 : extra.sjinfo = sjinfo;
152 561878 : extra.param_source_rels = NULL;
153 :
154 : /*
155 : * See if the inner relation is provably unique for this outer rel.
156 : *
157 : * We have some special cases: for JOIN_SEMI and JOIN_ANTI, it doesn't
158 : * matter since the executor can make the equivalent optimization anyway;
159 : * we need not expend planner cycles on proofs. For JOIN_UNIQUE_INNER, we
160 : * must be considering a semijoin whose inner side is not provably unique
161 : * (else reduce_unique_semijoins would've simplified it), so there's no
162 : * point in calling innerrel_is_unique. However, if the LHS covers all of
163 : * the semijoin's min_lefthand, then it's appropriate to set inner_unique
164 : * because the path produced by create_unique_path will be unique relative
165 : * to the LHS. (If we have an LHS that's only part of the min_lefthand,
166 : * that is *not* true.) For JOIN_UNIQUE_OUTER, pass JOIN_INNER to avoid
167 : * letting that value escape this module.
168 : */
169 561878 : switch (jointype)
170 : {
171 8828 : case JOIN_SEMI:
172 : case JOIN_ANTI:
173 :
174 : /*
175 : * XXX it may be worth proving this to allow a Memoize to be
176 : * considered for Nested Loop Semi/Anti Joins.
177 : */
178 8828 : extra.inner_unique = false; /* well, unproven */
179 8828 : break;
180 4494 : case JOIN_UNIQUE_INNER:
181 8988 : extra.inner_unique = bms_is_subset(sjinfo->min_lefthand,
182 4494 : outerrel->relids);
183 4494 : break;
184 4494 : case JOIN_UNIQUE_OUTER:
185 4494 : extra.inner_unique = innerrel_is_unique(root,
186 : joinrel->relids,
187 : outerrel->relids,
188 : innerrel,
189 : JOIN_INNER,
190 : restrictlist,
191 : false);
192 4494 : break;
193 544062 : default:
194 544062 : extra.inner_unique = innerrel_is_unique(root,
195 : joinrel->relids,
196 : outerrel->relids,
197 : innerrel,
198 : jointype,
199 : restrictlist,
200 : false);
201 544062 : break;
202 : }
203 :
204 : /*
205 : * Find potential mergejoin clauses. We can skip this if we are not
206 : * interested in doing a mergejoin. However, mergejoin may be our only
207 : * way of implementing a full outer join, so override enable_mergejoin if
208 : * it's a full join.
209 : */
210 561878 : if (enable_mergejoin || jointype == JOIN_FULL)
211 558456 : extra.mergeclause_list = select_mergejoin_clauses(root,
212 : joinrel,
213 : outerrel,
214 : innerrel,
215 : restrictlist,
216 : jointype,
217 : &mergejoin_allowed);
218 :
219 : /*
220 : * If it's SEMI, ANTI, or inner_unique join, compute correction factors
221 : * for cost estimation. These will be the same for all paths.
222 : */
223 561878 : if (jointype == JOIN_SEMI || jointype == JOIN_ANTI || extra.inner_unique)
224 179386 : compute_semi_anti_join_factors(root, joinrel, outerrel, innerrel,
225 : jointype, sjinfo, restrictlist,
226 : &extra.semifactors);
227 :
228 : /*
229 : * Decide whether it's sensible to generate parameterized paths for this
230 : * joinrel, and if so, which relations such paths should require. There
231 : * is usually no need to create a parameterized result path unless there
232 : * is a join order restriction that prevents joining one of our input rels
233 : * directly to the parameter source rel instead of joining to the other
234 : * input rel. (But see allow_star_schema_join().) This restriction
235 : * reduces the number of parameterized paths we have to deal with at
236 : * higher join levels, without compromising the quality of the resulting
237 : * plan. We express the restriction as a Relids set that must overlap the
238 : * parameterization of any proposed join path. Note: param_source_rels
239 : * should contain only baserels, not OJ relids, so starting from
240 : * all_baserels not all_query_rels is correct.
241 : */
242 1223630 : foreach(lc, root->join_info_list)
243 : {
244 661752 : SpecialJoinInfo *sjinfo2 = (SpecialJoinInfo *) lfirst(lc);
245 :
246 : /*
247 : * SJ is relevant to this join if we have some part of its RHS
248 : * (possibly not all of it), and haven't yet joined to its LHS. (This
249 : * test is pretty simplistic, but should be sufficient considering the
250 : * join has already been proven legal.) If the SJ is relevant, it
251 : * presents constraints for joining to anything not in its RHS.
252 : */
253 661752 : if (bms_overlap(joinrelids, sjinfo2->min_righthand) &&
254 434702 : !bms_overlap(joinrelids, sjinfo2->min_lefthand))
255 20308 : extra.param_source_rels = bms_join(extra.param_source_rels,
256 20308 : bms_difference(root->all_baserels,
257 20308 : sjinfo2->min_righthand));
258 :
259 : /* full joins constrain both sides symmetrically */
260 666584 : if (sjinfo2->jointype == JOIN_FULL &&
261 4832 : bms_overlap(joinrelids, sjinfo2->min_lefthand) &&
262 4776 : !bms_overlap(joinrelids, sjinfo2->min_righthand))
263 672 : extra.param_source_rels = bms_join(extra.param_source_rels,
264 672 : bms_difference(root->all_baserels,
265 672 : sjinfo2->min_lefthand));
266 : }
267 :
268 : /*
269 : * However, when a LATERAL subquery is involved, there will simply not be
270 : * any paths for the joinrel that aren't parameterized by whatever the
271 : * subquery is parameterized by, unless its parameterization is resolved
272 : * within the joinrel. So we might as well allow additional dependencies
273 : * on whatever residual lateral dependencies the joinrel will have.
274 : */
275 1123756 : extra.param_source_rels = bms_add_members(extra.param_source_rels,
276 561878 : joinrel->lateral_relids);
277 :
278 : /*
279 : * 1. Consider mergejoin paths where both relations must be explicitly
280 : * sorted. Skip this if we can't mergejoin.
281 : */
282 561878 : if (mergejoin_allowed)
283 553504 : sort_inner_and_outer(root, joinrel, outerrel, innerrel,
284 : jointype, &extra);
285 :
286 : /*
287 : * 2. Consider paths where the outer relation need not be explicitly
288 : * sorted. This includes both nestloops and mergejoins where the outer
289 : * path is already ordered. Again, skip this if we can't mergejoin.
290 : * (That's okay because we know that nestloop can't handle
291 : * right/right-anti/full joins at all, so it wouldn't work in the
292 : * prohibited cases either.)
293 : */
294 561878 : if (mergejoin_allowed)
295 553504 : match_unsorted_outer(root, joinrel, outerrel, innerrel,
296 : jointype, &extra);
297 :
298 : #ifdef NOT_USED
299 :
300 : /*
301 : * 3. Consider paths where the inner relation need not be explicitly
302 : * sorted. This includes mergejoins only (nestloops were already built in
303 : * match_unsorted_outer).
304 : *
305 : * Diked out as redundant 2/13/2000 -- tgl. There isn't any really
306 : * significant difference between the inner and outer side of a mergejoin,
307 : * so match_unsorted_inner creates no paths that aren't equivalent to
308 : * those made by match_unsorted_outer when add_paths_to_joinrel() is
309 : * invoked with the two rels given in the other order.
310 : */
311 : if (mergejoin_allowed)
312 : match_unsorted_inner(root, joinrel, outerrel, innerrel,
313 : jointype, &extra);
314 : #endif
315 :
316 : /*
317 : * 4. Consider paths where both outer and inner relations must be hashed
318 : * before being joined. As above, disregard enable_hashjoin for full
319 : * joins, because there may be no other alternative.
320 : */
321 561878 : if (enable_hashjoin || jointype == JOIN_FULL)
322 557014 : hash_inner_and_outer(root, joinrel, outerrel, innerrel,
323 : jointype, &extra);
324 :
325 : /*
326 : * 5. If inner and outer relations are foreign tables (or joins) belonging
327 : * to the same server and assigned to the same user to check access
328 : * permissions as, give the FDW a chance to push down joins.
329 : */
330 561878 : if (joinrel->fdwroutine &&
331 2398 : joinrel->fdwroutine->GetForeignJoinPaths)
332 2394 : joinrel->fdwroutine->GetForeignJoinPaths(root, joinrel,
333 : outerrel, innerrel,
334 : jointype, &extra);
335 :
336 : /*
337 : * 6. Finally, give extensions a chance to manipulate the path list. They
338 : * could add new paths (such as CustomPaths) by calling add_path(), or
339 : * add_partial_path() if parallel aware. They could also delete or modify
340 : * paths added by the core code.
341 : */
342 561878 : if (set_join_pathlist_hook)
343 0 : set_join_pathlist_hook(root, joinrel, outerrel, innerrel,
344 : jointype, &extra);
345 561878 : }
346 :
347 : /*
348 : * We override the param_source_rels heuristic to accept nestloop paths in
349 : * which the outer rel satisfies some but not all of the inner path's
350 : * parameterization. This is necessary to get good plans for star-schema
351 : * scenarios, in which a parameterized path for a large table may require
352 : * parameters from multiple small tables that will not get joined directly to
353 : * each other. We can handle that by stacking nestloops that have the small
354 : * tables on the outside; but this breaks the rule the param_source_rels
355 : * heuristic is based on, namely that parameters should not be passed down
356 : * across joins unless there's a join-order-constraint-based reason to do so.
357 : * So we ignore the param_source_rels restriction when this case applies.
358 : *
359 : * allow_star_schema_join() returns true if the param_source_rels restriction
360 : * should be overridden, ie, it's okay to perform this join.
361 : */
362 : static inline bool
363 215838 : allow_star_schema_join(PlannerInfo *root,
364 : Relids outerrelids,
365 : Relids inner_paramrels)
366 : {
367 : /*
368 : * It's a star-schema case if the outer rel provides some but not all of
369 : * the inner rel's parameterization.
370 : */
371 250236 : return (bms_overlap(inner_paramrels, outerrelids) &&
372 34398 : bms_nonempty_difference(inner_paramrels, outerrelids));
373 : }
374 :
375 : /*
376 : * If the parameterization is only partly satisfied by the outer rel,
377 : * the unsatisfied part can't include any outer-join relids that could
378 : * null rels of the satisfied part. That would imply that we're trying
379 : * to use a clause involving a Var with nonempty varnullingrels at
380 : * a join level where that value isn't yet computable.
381 : *
382 : * In practice, this test never finds a problem because earlier join order
383 : * restrictions prevent us from attempting a join that would cause a problem.
384 : * (That's unsurprising, because the code worked before we ever added
385 : * outer-join relids to expression relids.) It still seems worth checking
386 : * as a backstop, but we only do so in assert-enabled builds.
387 : */
388 : #ifdef USE_ASSERT_CHECKING
389 : static inline bool
390 : have_unsafe_outer_join_ref(PlannerInfo *root,
391 : Relids outerrelids,
392 : Relids inner_paramrels)
393 : {
394 : bool result = false;
395 : Relids unsatisfied = bms_difference(inner_paramrels, outerrelids);
396 : Relids satisfied = bms_intersect(inner_paramrels, outerrelids);
397 :
398 : if (bms_overlap(unsatisfied, root->outer_join_rels))
399 : {
400 : ListCell *lc;
401 :
402 : foreach(lc, root->join_info_list)
403 : {
404 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(lc);
405 :
406 : if (!bms_is_member(sjinfo->ojrelid, unsatisfied))
407 : continue; /* not relevant */
408 : if (bms_overlap(satisfied, sjinfo->min_righthand) ||
409 : (sjinfo->jointype == JOIN_FULL &&
410 : bms_overlap(satisfied, sjinfo->min_lefthand)))
411 : {
412 : result = true; /* doesn't work */
413 : break;
414 : }
415 : }
416 : }
417 :
418 : /* Waste no memory when we reject a path here */
419 : bms_free(unsatisfied);
420 : bms_free(satisfied);
421 :
422 : return result;
423 : }
424 : #endif /* USE_ASSERT_CHECKING */
425 :
426 : /*
427 : * paraminfo_get_equal_hashops
428 : * Determine if the clauses in param_info and innerrel's lateral_vars
429 : * can be hashed.
430 : * Returns true if hashing is possible, otherwise false.
431 : *
432 : * Additionally, on success we collect the outer expressions and the
433 : * appropriate equality operators for each hashable parameter to innerrel.
434 : * These are returned in parallel lists in *param_exprs and *operators.
435 : * We also set *binary_mode to indicate whether strict binary matching is
436 : * required.
437 : */
438 : static bool
439 326622 : paraminfo_get_equal_hashops(PlannerInfo *root, ParamPathInfo *param_info,
440 : RelOptInfo *outerrel, RelOptInfo *innerrel,
441 : List **param_exprs, List **operators,
442 : bool *binary_mode)
443 :
444 : {
445 : ListCell *lc;
446 :
447 326622 : *param_exprs = NIL;
448 326622 : *operators = NIL;
449 326622 : *binary_mode = false;
450 :
451 : /* Add join clauses from param_info to the hash key */
452 326622 : if (param_info != NULL)
453 : {
454 326622 : List *clauses = param_info->ppi_clauses;
455 :
456 592848 : foreach(lc, clauses)
457 : {
458 350414 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
459 : OpExpr *opexpr;
460 : Node *expr;
461 : Oid hasheqoperator;
462 :
463 350414 : opexpr = (OpExpr *) rinfo->clause;
464 :
465 : /*
466 : * Bail if the rinfo is not compatible. We need a join OpExpr
467 : * with 2 args.
468 : */
469 350414 : if (!IsA(opexpr, OpExpr) || list_length(opexpr->args) != 2 ||
470 327732 : !clause_sides_match_join(rinfo, outerrel, innerrel))
471 : {
472 84044 : list_free(*operators);
473 84044 : list_free(*param_exprs);
474 84188 : return false;
475 : }
476 :
477 266370 : if (rinfo->outer_is_left)
478 : {
479 158806 : expr = (Node *) linitial(opexpr->args);
480 158806 : hasheqoperator = rinfo->left_hasheqoperator;
481 : }
482 : else
483 : {
484 107564 : expr = (Node *) lsecond(opexpr->args);
485 107564 : hasheqoperator = rinfo->right_hasheqoperator;
486 : }
487 :
488 : /* can't do memoize if we can't hash the outer type */
489 266370 : if (!OidIsValid(hasheqoperator))
490 : {
491 144 : list_free(*operators);
492 144 : list_free(*param_exprs);
493 144 : return false;
494 : }
495 :
496 : /*
497 : * 'expr' may already exist as a parameter from a previous item in
498 : * ppi_clauses. No need to include it again, however we'd better
499 : * ensure we do switch into binary mode if required. See below.
500 : */
501 266226 : if (!list_member(*param_exprs, expr))
502 : {
503 266220 : *operators = lappend_oid(*operators, hasheqoperator);
504 266220 : *param_exprs = lappend(*param_exprs, expr);
505 : }
506 :
507 : /*
508 : * When the join operator is not hashable then it's possible that
509 : * the operator will be able to distinguish something that the
510 : * hash equality operator could not. For example with floating
511 : * point types -0.0 and +0.0 are classed as equal by the hash
512 : * function and equality function, but some other operator may be
513 : * able to tell those values apart. This means that we must put
514 : * memoize into binary comparison mode so that it does bit-by-bit
515 : * comparisons rather than a "logical" comparison as it would
516 : * using the hash equality operator.
517 : */
518 266226 : if (!OidIsValid(rinfo->hashjoinoperator))
519 1052 : *binary_mode = true;
520 : }
521 : }
522 :
523 : /* Now add any lateral vars to the cache key too */
524 246026 : foreach(lc, innerrel->lateral_vars)
525 : {
526 3742 : Node *expr = (Node *) lfirst(lc);
527 : TypeCacheEntry *typentry;
528 :
529 : /* Reject if there are any volatile functions in lateral vars */
530 3742 : if (contain_volatile_functions(expr))
531 : {
532 0 : list_free(*operators);
533 0 : list_free(*param_exprs);
534 150 : return false;
535 : }
536 :
537 3742 : typentry = lookup_type_cache(exprType(expr),
538 : TYPECACHE_HASH_PROC | TYPECACHE_EQ_OPR);
539 :
540 : /* can't use memoize without a valid hash proc and equals operator */
541 3742 : if (!OidIsValid(typentry->hash_proc) || !OidIsValid(typentry->eq_opr))
542 : {
543 150 : list_free(*operators);
544 150 : list_free(*param_exprs);
545 150 : return false;
546 : }
547 :
548 : /*
549 : * 'expr' may already exist as a parameter from the ppi_clauses. No
550 : * need to include it again, however we'd better ensure we do switch
551 : * into binary mode.
552 : */
553 3592 : if (!list_member(*param_exprs, expr))
554 : {
555 3190 : *operators = lappend_oid(*operators, typentry->eq_opr);
556 3190 : *param_exprs = lappend(*param_exprs, expr);
557 : }
558 :
559 : /*
560 : * We must go into binary mode as we don't have too much of an idea of
561 : * how these lateral Vars are being used. See comment above when we
562 : * set *binary_mode for the non-lateral Var case. This could be
563 : * relaxed a bit if we had the RestrictInfos and knew the operators
564 : * being used, however for cases like Vars that are arguments to
565 : * functions we must operate in binary mode as we don't have
566 : * visibility into what the function is doing with the Vars.
567 : */
568 3592 : *binary_mode = true;
569 : }
570 :
571 : /* We're okay to use memoize */
572 242284 : return true;
573 : }
574 :
575 : /*
576 : * get_memoize_path
577 : * If possible, make and return a Memoize path atop of 'inner_path'.
578 : * Otherwise return NULL.
579 : */
580 : static Path *
581 1427542 : get_memoize_path(PlannerInfo *root, RelOptInfo *innerrel,
582 : RelOptInfo *outerrel, Path *inner_path,
583 : Path *outer_path, JoinType jointype,
584 : JoinPathExtraData *extra)
585 : {
586 : List *param_exprs;
587 : List *hash_operators;
588 : ListCell *lc;
589 : bool binary_mode;
590 :
591 : /* Obviously not if it's disabled */
592 1427542 : if (!enable_memoize)
593 634 : return NULL;
594 :
595 : /*
596 : * We can safely not bother with all this unless we expect to perform more
597 : * than one inner scan. The first scan is always going to be a cache
598 : * miss. This would likely fail later anyway based on costs, so this is
599 : * really just to save some wasted effort.
600 : */
601 1426908 : if (outer_path->parent->rows < 2)
602 461730 : return NULL;
603 :
604 : /*
605 : * We can only have a memoize node when there's some kind of cache key,
606 : * either parameterized path clauses or lateral Vars. No cache key sounds
607 : * more like something a Materialize node might be more useful for.
608 : */
609 965178 : if ((inner_path->param_info == NULL ||
610 400622 : inner_path->param_info->ppi_clauses == NIL) &&
611 581130 : innerrel->lateral_vars == NIL)
612 578640 : return NULL;
613 :
614 : /*
615 : * Currently we don't do this for SEMI and ANTI joins unless they're
616 : * marked as inner_unique. This is because nested loop SEMI/ANTI joins
617 : * don't scan the inner node to completion, which will mean memoize cannot
618 : * mark the cache entry as complete.
619 : *
620 : * XXX Currently we don't attempt to mark SEMI/ANTI joins as inner_unique
621 : * = true. Should we? See add_paths_to_joinrel()
622 : */
623 386538 : if (!extra->inner_unique && (jointype == JOIN_SEMI ||
624 : jointype == JOIN_ANTI))
625 8436 : return NULL;
626 :
627 : /*
628 : * Memoize normally marks cache entries as complete when it runs out of
629 : * tuples to read from its subplan. However, with unique joins, Nested
630 : * Loop will skip to the next outer tuple after finding the first matching
631 : * inner tuple. This means that we may not read the inner side of the
632 : * join to completion which leaves no opportunity to mark the cache entry
633 : * as complete. To work around that, when the join is unique we
634 : * automatically mark cache entries as complete after fetching the first
635 : * tuple. This works when the entire join condition is parameterized.
636 : * Otherwise, when the parameterization is only a subset of the join
637 : * condition, we can't be sure which part of it causes the join to be
638 : * unique. This means there are no guarantees that only 1 tuple will be
639 : * read. We cannot mark the cache entry as complete after reading the
640 : * first tuple without that guarantee. This means the scope of Memoize
641 : * node's usefulness is limited to only outer rows that have no join
642 : * partner as this is the only case where Nested Loop would exhaust the
643 : * inner scan of a unique join. Since the scope is limited to that, we
644 : * just don't bother making a memoize path in this case.
645 : *
646 : * Lateral vars needn't be considered here as they're not considered when
647 : * determining if the join is unique.
648 : *
649 : * XXX this could be enabled if the remaining join quals were made part of
650 : * the inner scan's filter instead of the join filter. Maybe it's worth
651 : * considering doing that?
652 : */
653 378102 : if (extra->inner_unique &&
654 455128 : (inner_path->param_info == NULL ||
655 227564 : bms_num_members(inner_path->param_info->ppi_serials) <
656 227564 : list_length(extra->restrictlist)))
657 51466 : return NULL;
658 :
659 : /*
660 : * We can't use a memoize node if there are volatile functions in the
661 : * inner rel's target list or restrict list. A cache hit could reduce the
662 : * number of calls to these functions.
663 : */
664 326636 : if (contain_volatile_functions((Node *) innerrel->reltarget))
665 0 : return NULL;
666 :
667 533962 : foreach(lc, innerrel->baserestrictinfo)
668 : {
669 207338 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
670 :
671 207338 : if (contain_volatile_functions((Node *) rinfo))
672 12 : return NULL;
673 : }
674 :
675 : /*
676 : * Also check the parameterized path restrictinfos for volatile functions.
677 : * Indexed functions must be immutable so shouldn't have any volatile
678 : * functions, however, with a lateral join the inner scan may not be an
679 : * index scan.
680 : */
681 326624 : if (inner_path->param_info != NULL)
682 : {
683 703998 : foreach(lc, inner_path->param_info->ppi_clauses)
684 : {
685 377376 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
686 :
687 377376 : if (contain_volatile_functions((Node *) rinfo))
688 2 : return NULL;
689 : }
690 : }
691 :
692 : /* Check if we have hash ops for each parameter to the path */
693 326622 : if (paraminfo_get_equal_hashops(root,
694 : inner_path->param_info,
695 326622 : outerrel->top_parent ?
696 : outerrel->top_parent : outerrel,
697 : innerrel,
698 : ¶m_exprs,
699 : &hash_operators,
700 : &binary_mode))
701 : {
702 242284 : return (Path *) create_memoize_path(root,
703 : innerrel,
704 : inner_path,
705 : param_exprs,
706 : hash_operators,
707 242284 : extra->inner_unique,
708 : binary_mode,
709 : outer_path->rows);
710 : }
711 :
712 84338 : return NULL;
713 : }
714 :
715 : /*
716 : * try_nestloop_path
717 : * Consider a nestloop join path; if it appears useful, push it into
718 : * the joinrel's pathlist via add_path().
719 : */
720 : static void
721 2461986 : try_nestloop_path(PlannerInfo *root,
722 : RelOptInfo *joinrel,
723 : Path *outer_path,
724 : Path *inner_path,
725 : List *pathkeys,
726 : JoinType jointype,
727 : JoinPathExtraData *extra)
728 : {
729 : Relids required_outer;
730 : JoinCostWorkspace workspace;
731 2461986 : RelOptInfo *innerrel = inner_path->parent;
732 2461986 : RelOptInfo *outerrel = outer_path->parent;
733 : Relids innerrelids;
734 : Relids outerrelids;
735 2461986 : Relids inner_paramrels = PATH_REQ_OUTER(inner_path);
736 2461986 : Relids outer_paramrels = PATH_REQ_OUTER(outer_path);
737 :
738 : /*
739 : * If we are forming an outer join at this join, it's nonsensical to use
740 : * an input path that uses the outer join as part of its parameterization.
741 : * (This can happen despite our join order restrictions, since those apply
742 : * to what is in an input relation not what its parameters are.)
743 : */
744 3085602 : if (extra->sjinfo->ojrelid != 0 &&
745 1247232 : (bms_is_member(extra->sjinfo->ojrelid, inner_paramrels) ||
746 623616 : bms_is_member(extra->sjinfo->ojrelid, outer_paramrels)))
747 215626 : return;
748 :
749 : /*
750 : * Any parameterization of the input paths refers to topmost parents of
751 : * the relevant relations, because reparameterize_path_by_child() hasn't
752 : * been called yet. So we must consider topmost parents of the relations
753 : * being joined, too, while determining parameterization of the result and
754 : * checking for disallowed parameterization cases.
755 : */
756 2461866 : if (innerrel->top_parent_relids)
757 33076 : innerrelids = innerrel->top_parent_relids;
758 : else
759 2428790 : innerrelids = innerrel->relids;
760 :
761 2461866 : if (outerrel->top_parent_relids)
762 33076 : outerrelids = outerrel->top_parent_relids;
763 : else
764 2428790 : outerrelids = outerrel->relids;
765 :
766 : /*
767 : * Check to see if proposed path is still parameterized, and reject if the
768 : * parameterization wouldn't be sensible --- unless allow_star_schema_join
769 : * says to allow it anyway. Also, we must reject if have_dangerous_phv
770 : * doesn't like the look of it, which could only happen if the nestloop is
771 : * still parameterized.
772 : */
773 2461866 : required_outer = calc_nestloop_required_outer(outerrelids, outer_paramrels,
774 : innerrelids, inner_paramrels);
775 2461866 : if (required_outer &&
776 248392 : ((!bms_overlap(required_outer, extra->param_source_rels) &&
777 248820 : !allow_star_schema_join(root, outerrelids, inner_paramrels)) ||
778 32982 : have_dangerous_phv(root, outerrelids, inner_paramrels)))
779 : {
780 : /* Waste no memory when we reject a path here */
781 215506 : bms_free(required_outer);
782 215506 : return;
783 : }
784 :
785 : /* If we got past that, we shouldn't have any unsafe outer-join refs */
786 : Assert(!have_unsafe_outer_join_ref(root, outerrelids, inner_paramrels));
787 :
788 : /*
789 : * If the inner path is parameterized, it is parameterized by the topmost
790 : * parent of the outer rel, not the outer rel itself. We will need to
791 : * translate the parameterization, if this path is chosen, during
792 : * create_plan(). Here we just check whether we will be able to perform
793 : * the translation, and if not avoid creating a nestloop path.
794 : */
795 2246360 : if (PATH_PARAM_BY_PARENT(inner_path, outer_path->parent) &&
796 10672 : !path_is_reparameterizable_by_child(inner_path, outer_path->parent))
797 : {
798 0 : bms_free(required_outer);
799 0 : return;
800 : }
801 :
802 : /*
803 : * Do a precheck to quickly eliminate obviously-inferior paths. We
804 : * calculate a cheap lower bound on the path's cost and then use
805 : * add_path_precheck() to see if the path is clearly going to be dominated
806 : * by some existing path for the joinrel. If not, do the full pushup with
807 : * creating a fully valid path structure and submitting it to add_path().
808 : * The latter two steps are expensive enough to make this two-phase
809 : * methodology worthwhile.
810 : */
811 2246360 : initial_cost_nestloop(root, &workspace, jointype,
812 : outer_path, inner_path, extra);
813 :
814 2246360 : if (add_path_precheck(joinrel,
815 : workspace.startup_cost, workspace.total_cost,
816 : pathkeys, required_outer))
817 : {
818 1127208 : add_path(joinrel, (Path *)
819 1127208 : create_nestloop_path(root,
820 : joinrel,
821 : jointype,
822 : &workspace,
823 : extra,
824 : outer_path,
825 : inner_path,
826 : extra->restrictlist,
827 : pathkeys,
828 : required_outer));
829 : }
830 : else
831 : {
832 : /* Waste no memory when we reject a path here */
833 1119152 : bms_free(required_outer);
834 : }
835 : }
836 :
837 : /*
838 : * try_partial_nestloop_path
839 : * Consider a partial nestloop join path; if it appears useful, push it into
840 : * the joinrel's partial_pathlist via add_partial_path().
841 : */
842 : static void
843 26212 : try_partial_nestloop_path(PlannerInfo *root,
844 : RelOptInfo *joinrel,
845 : Path *outer_path,
846 : Path *inner_path,
847 : List *pathkeys,
848 : JoinType jointype,
849 : JoinPathExtraData *extra)
850 : {
851 : JoinCostWorkspace workspace;
852 :
853 : /*
854 : * If the inner path is parameterized, the parameterization must be fully
855 : * satisfied by the proposed outer path. Parameterized partial paths are
856 : * not supported. The caller should already have verified that no lateral
857 : * rels are required here.
858 : */
859 : Assert(bms_is_empty(joinrel->lateral_relids));
860 26212 : if (inner_path->param_info != NULL)
861 : {
862 13302 : Relids inner_paramrels = inner_path->param_info->ppi_req_outer;
863 13302 : RelOptInfo *outerrel = outer_path->parent;
864 : Relids outerrelids;
865 :
866 : /*
867 : * The inner and outer paths are parameterized, if at all, by the top
868 : * level parents, not the child relations, so we must use those relids
869 : * for our parameterization tests.
870 : */
871 13302 : if (outerrel->top_parent_relids)
872 9972 : outerrelids = outerrel->top_parent_relids;
873 : else
874 3330 : outerrelids = outerrel->relids;
875 :
876 13302 : if (!bms_is_subset(inner_paramrels, outerrelids))
877 18370 : return;
878 : }
879 :
880 : /*
881 : * If the inner path is parameterized, it is parameterized by the topmost
882 : * parent of the outer rel, not the outer rel itself. We will need to
883 : * translate the parameterization, if this path is chosen, during
884 : * create_plan(). Here we just check whether we will be able to perform
885 : * the translation, and if not avoid creating a nestloop path.
886 : */
887 25168 : if (PATH_PARAM_BY_PARENT(inner_path, outer_path->parent) &&
888 9180 : !path_is_reparameterizable_by_child(inner_path, outer_path->parent))
889 0 : return;
890 :
891 : /*
892 : * Before creating a path, get a quick lower bound on what it is likely to
893 : * cost. Bail out right away if it looks terrible.
894 : */
895 25168 : initial_cost_nestloop(root, &workspace, jointype,
896 : outer_path, inner_path, extra);
897 25168 : if (!add_partial_path_precheck(joinrel, workspace.total_cost, pathkeys))
898 17326 : return;
899 :
900 : /* Might be good enough to be worth trying, so let's try it. */
901 7842 : add_partial_path(joinrel, (Path *)
902 7842 : create_nestloop_path(root,
903 : joinrel,
904 : jointype,
905 : &workspace,
906 : extra,
907 : outer_path,
908 : inner_path,
909 : extra->restrictlist,
910 : pathkeys,
911 : NULL));
912 : }
913 :
914 : /*
915 : * try_mergejoin_path
916 : * Consider a merge join path; if it appears useful, push it into
917 : * the joinrel's pathlist via add_path().
918 : */
919 : static void
920 1025734 : try_mergejoin_path(PlannerInfo *root,
921 : RelOptInfo *joinrel,
922 : Path *outer_path,
923 : Path *inner_path,
924 : List *pathkeys,
925 : List *mergeclauses,
926 : List *outersortkeys,
927 : List *innersortkeys,
928 : JoinType jointype,
929 : JoinPathExtraData *extra,
930 : bool is_partial)
931 : {
932 : Relids required_outer;
933 : JoinCostWorkspace workspace;
934 :
935 1025734 : if (is_partial)
936 : {
937 6018 : try_partial_mergejoin_path(root,
938 : joinrel,
939 : outer_path,
940 : inner_path,
941 : pathkeys,
942 : mergeclauses,
943 : outersortkeys,
944 : innersortkeys,
945 : jointype,
946 : extra);
947 32398 : return;
948 : }
949 :
950 : /*
951 : * If we are forming an outer join at this join, it's nonsensical to use
952 : * an input path that uses the outer join as part of its parameterization.
953 : * (This can happen despite our join order restrictions, since those apply
954 : * to what is in an input relation not what its parameters are.)
955 : */
956 1404362 : if (extra->sjinfo->ojrelid != 0 &&
957 769292 : (bms_is_member(extra->sjinfo->ojrelid, PATH_REQ_OUTER(inner_path)) ||
958 384646 : bms_is_member(extra->sjinfo->ojrelid, PATH_REQ_OUTER(outer_path))))
959 12 : return;
960 :
961 : /*
962 : * Check to see if proposed path is still parameterized, and reject if the
963 : * parameterization wouldn't be sensible.
964 : */
965 1019704 : required_outer = calc_non_nestloop_required_outer(outer_path,
966 : inner_path);
967 1019704 : if (required_outer &&
968 28840 : !bms_overlap(required_outer, extra->param_source_rels))
969 : {
970 : /* Waste no memory when we reject a path here */
971 26368 : bms_free(required_outer);
972 26368 : return;
973 : }
974 :
975 : /*
976 : * If the given paths are already well enough ordered, we can skip doing
977 : * an explicit sort.
978 : */
979 1477034 : if (outersortkeys &&
980 483698 : pathkeys_contained_in(outersortkeys, outer_path->pathkeys))
981 13986 : outersortkeys = NIL;
982 1794824 : if (innersortkeys &&
983 801488 : pathkeys_contained_in(innersortkeys, inner_path->pathkeys))
984 23320 : innersortkeys = NIL;
985 :
986 : /*
987 : * See comments in try_nestloop_path().
988 : */
989 993336 : initial_cost_mergejoin(root, &workspace, jointype, mergeclauses,
990 : outer_path, inner_path,
991 : outersortkeys, innersortkeys,
992 : extra);
993 :
994 993336 : if (add_path_precheck(joinrel,
995 : workspace.startup_cost, workspace.total_cost,
996 : pathkeys, required_outer))
997 : {
998 244422 : add_path(joinrel, (Path *)
999 244422 : create_mergejoin_path(root,
1000 : joinrel,
1001 : jointype,
1002 : &workspace,
1003 : extra,
1004 : outer_path,
1005 : inner_path,
1006 : extra->restrictlist,
1007 : pathkeys,
1008 : required_outer,
1009 : mergeclauses,
1010 : outersortkeys,
1011 : innersortkeys));
1012 : }
1013 : else
1014 : {
1015 : /* Waste no memory when we reject a path here */
1016 748914 : bms_free(required_outer);
1017 : }
1018 : }
1019 :
1020 : /*
1021 : * try_partial_mergejoin_path
1022 : * Consider a partial merge join path; if it appears useful, push it into
1023 : * the joinrel's pathlist via add_partial_path().
1024 : */
1025 : static void
1026 18156 : try_partial_mergejoin_path(PlannerInfo *root,
1027 : RelOptInfo *joinrel,
1028 : Path *outer_path,
1029 : Path *inner_path,
1030 : List *pathkeys,
1031 : List *mergeclauses,
1032 : List *outersortkeys,
1033 : List *innersortkeys,
1034 : JoinType jointype,
1035 : JoinPathExtraData *extra)
1036 : {
1037 : JoinCostWorkspace workspace;
1038 :
1039 : /*
1040 : * See comments in try_partial_hashjoin_path().
1041 : */
1042 : Assert(bms_is_empty(joinrel->lateral_relids));
1043 18156 : if (inner_path->param_info != NULL)
1044 : {
1045 0 : Relids inner_paramrels = inner_path->param_info->ppi_req_outer;
1046 :
1047 0 : if (!bms_is_empty(inner_paramrels))
1048 9098 : return;
1049 : }
1050 :
1051 : /*
1052 : * If the given paths are already well enough ordered, we can skip doing
1053 : * an explicit sort.
1054 : */
1055 30294 : if (outersortkeys &&
1056 12138 : pathkeys_contained_in(outersortkeys, outer_path->pathkeys))
1057 102 : outersortkeys = NIL;
1058 33870 : if (innersortkeys &&
1059 15714 : pathkeys_contained_in(innersortkeys, inner_path->pathkeys))
1060 252 : innersortkeys = NIL;
1061 :
1062 : /*
1063 : * See comments in try_partial_nestloop_path().
1064 : */
1065 18156 : initial_cost_mergejoin(root, &workspace, jointype, mergeclauses,
1066 : outer_path, inner_path,
1067 : outersortkeys, innersortkeys,
1068 : extra);
1069 :
1070 18156 : if (!add_partial_path_precheck(joinrel, workspace.total_cost, pathkeys))
1071 9098 : return;
1072 :
1073 : /* Might be good enough to be worth trying, so let's try it. */
1074 9058 : add_partial_path(joinrel, (Path *)
1075 9058 : create_mergejoin_path(root,
1076 : joinrel,
1077 : jointype,
1078 : &workspace,
1079 : extra,
1080 : outer_path,
1081 : inner_path,
1082 : extra->restrictlist,
1083 : pathkeys,
1084 : NULL,
1085 : mergeclauses,
1086 : outersortkeys,
1087 : innersortkeys));
1088 : }
1089 :
1090 : /*
1091 : * try_hashjoin_path
1092 : * Consider a hash join path; if it appears useful, push it into
1093 : * the joinrel's pathlist via add_path().
1094 : */
1095 : static void
1096 600536 : try_hashjoin_path(PlannerInfo *root,
1097 : RelOptInfo *joinrel,
1098 : Path *outer_path,
1099 : Path *inner_path,
1100 : List *hashclauses,
1101 : JoinType jointype,
1102 : JoinPathExtraData *extra)
1103 : {
1104 : Relids required_outer;
1105 : JoinCostWorkspace workspace;
1106 :
1107 : /*
1108 : * If we are forming an outer join at this join, it's nonsensical to use
1109 : * an input path that uses the outer join as part of its parameterization.
1110 : * (This can happen despite our join order restrictions, since those apply
1111 : * to what is in an input relation not what its parameters are.)
1112 : */
1113 832742 : if (extra->sjinfo->ojrelid != 0 &&
1114 464382 : (bms_is_member(extra->sjinfo->ojrelid, PATH_REQ_OUTER(inner_path)) ||
1115 232176 : bms_is_member(extra->sjinfo->ojrelid, PATH_REQ_OUTER(outer_path))))
1116 81234 : return;
1117 :
1118 : /*
1119 : * Check to see if proposed path is still parameterized, and reject if the
1120 : * parameterization wouldn't be sensible.
1121 : */
1122 600476 : required_outer = calc_non_nestloop_required_outer(outer_path,
1123 : inner_path);
1124 600476 : if (required_outer &&
1125 93790 : !bms_overlap(required_outer, extra->param_source_rels))
1126 : {
1127 : /* Waste no memory when we reject a path here */
1128 81174 : bms_free(required_outer);
1129 81174 : return;
1130 : }
1131 :
1132 : /*
1133 : * See comments in try_nestloop_path(). Also note that hashjoin paths
1134 : * never have any output pathkeys, per comments in create_hashjoin_path.
1135 : */
1136 519302 : initial_cost_hashjoin(root, &workspace, jointype, hashclauses,
1137 : outer_path, inner_path, extra, false);
1138 :
1139 519302 : if (add_path_precheck(joinrel,
1140 : workspace.startup_cost, workspace.total_cost,
1141 : NIL, required_outer))
1142 : {
1143 211608 : add_path(joinrel, (Path *)
1144 211608 : create_hashjoin_path(root,
1145 : joinrel,
1146 : jointype,
1147 : &workspace,
1148 : extra,
1149 : outer_path,
1150 : inner_path,
1151 : false, /* parallel_hash */
1152 : extra->restrictlist,
1153 : required_outer,
1154 : hashclauses));
1155 : }
1156 : else
1157 : {
1158 : /* Waste no memory when we reject a path here */
1159 307694 : bms_free(required_outer);
1160 : }
1161 : }
1162 :
1163 : /*
1164 : * try_partial_hashjoin_path
1165 : * Consider a partial hashjoin join path; if it appears useful, push it into
1166 : * the joinrel's partial_pathlist via add_partial_path().
1167 : * The outer side is partial. If parallel_hash is true, then the inner path
1168 : * must be partial and will be run in parallel to create one or more shared
1169 : * hash tables; otherwise the inner path must be complete and a copy of it
1170 : * is run in every process to create separate identical private hash tables.
1171 : */
1172 : static void
1173 20094 : try_partial_hashjoin_path(PlannerInfo *root,
1174 : RelOptInfo *joinrel,
1175 : Path *outer_path,
1176 : Path *inner_path,
1177 : List *hashclauses,
1178 : JoinType jointype,
1179 : JoinPathExtraData *extra,
1180 : bool parallel_hash)
1181 : {
1182 : JoinCostWorkspace workspace;
1183 :
1184 : /*
1185 : * If the inner path is parameterized, the parameterization must be fully
1186 : * satisfied by the proposed outer path. Parameterized partial paths are
1187 : * not supported. The caller should already have verified that no lateral
1188 : * rels are required here.
1189 : */
1190 : Assert(bms_is_empty(joinrel->lateral_relids));
1191 20094 : if (inner_path->param_info != NULL)
1192 : {
1193 0 : Relids inner_paramrels = inner_path->param_info->ppi_req_outer;
1194 :
1195 0 : if (!bms_is_empty(inner_paramrels))
1196 9532 : return;
1197 : }
1198 :
1199 : /*
1200 : * Before creating a path, get a quick lower bound on what it is likely to
1201 : * cost. Bail out right away if it looks terrible.
1202 : */
1203 20094 : initial_cost_hashjoin(root, &workspace, jointype, hashclauses,
1204 : outer_path, inner_path, extra, parallel_hash);
1205 20094 : if (!add_partial_path_precheck(joinrel, workspace.total_cost, NIL))
1206 9532 : return;
1207 :
1208 : /* Might be good enough to be worth trying, so let's try it. */
1209 10562 : add_partial_path(joinrel, (Path *)
1210 10562 : create_hashjoin_path(root,
1211 : joinrel,
1212 : jointype,
1213 : &workspace,
1214 : extra,
1215 : outer_path,
1216 : inner_path,
1217 : parallel_hash,
1218 : extra->restrictlist,
1219 : NULL,
1220 : hashclauses));
1221 : }
1222 :
1223 : /*
1224 : * clause_sides_match_join
1225 : * Determine whether a join clause is of the right form to use in this join.
1226 : *
1227 : * We already know that the clause is a binary opclause referencing only the
1228 : * rels in the current join. The point here is to check whether it has the
1229 : * form "outerrel_expr op innerrel_expr" or "innerrel_expr op outerrel_expr",
1230 : * rather than mixing outer and inner vars on either side. If it matches,
1231 : * we set the transient flag outer_is_left to identify which side is which.
1232 : */
1233 : static inline bool
1234 1314006 : clause_sides_match_join(RestrictInfo *rinfo, RelOptInfo *outerrel,
1235 : RelOptInfo *innerrel)
1236 : {
1237 1968366 : if (bms_is_subset(rinfo->left_relids, outerrel->relids) &&
1238 654360 : bms_is_subset(rinfo->right_relids, innerrel->relids))
1239 : {
1240 : /* lefthand side is outer */
1241 654012 : rinfo->outer_is_left = true;
1242 654012 : return true;
1243 : }
1244 1302192 : else if (bms_is_subset(rinfo->left_relids, innerrel->relids) &&
1245 642198 : bms_is_subset(rinfo->right_relids, outerrel->relids))
1246 : {
1247 : /* righthand side is outer */
1248 597720 : rinfo->outer_is_left = false;
1249 597720 : return true;
1250 : }
1251 62274 : return false; /* no good for these input relations */
1252 : }
1253 :
1254 : /*
1255 : * sort_inner_and_outer
1256 : * Create mergejoin join paths by explicitly sorting both the outer and
1257 : * inner join relations on each available merge ordering.
1258 : *
1259 : * 'joinrel' is the join relation
1260 : * 'outerrel' is the outer join relation
1261 : * 'innerrel' is the inner join relation
1262 : * 'jointype' is the type of join to do
1263 : * 'extra' contains additional input values
1264 : */
1265 : static void
1266 553504 : sort_inner_and_outer(PlannerInfo *root,
1267 : RelOptInfo *joinrel,
1268 : RelOptInfo *outerrel,
1269 : RelOptInfo *innerrel,
1270 : JoinType jointype,
1271 : JoinPathExtraData *extra)
1272 : {
1273 553504 : JoinType save_jointype = jointype;
1274 : Path *outer_path;
1275 : Path *inner_path;
1276 553504 : Path *cheapest_partial_outer = NULL;
1277 553504 : Path *cheapest_safe_inner = NULL;
1278 : List *all_pathkeys;
1279 : ListCell *l;
1280 :
1281 : /*
1282 : * We only consider the cheapest-total-cost input paths, since we are
1283 : * assuming here that a sort is required. We will consider
1284 : * cheapest-startup-cost input paths later, and only if they don't need a
1285 : * sort.
1286 : *
1287 : * This function intentionally does not consider parameterized input
1288 : * paths, except when the cheapest-total is parameterized. If we did so,
1289 : * we'd have a combinatorial explosion of mergejoin paths of dubious
1290 : * value. This interacts with decisions elsewhere that also discriminate
1291 : * against mergejoins with parameterized inputs; see comments in
1292 : * src/backend/optimizer/README.
1293 : */
1294 553504 : outer_path = outerrel->cheapest_total_path;
1295 553504 : inner_path = innerrel->cheapest_total_path;
1296 :
1297 : /*
1298 : * If either cheapest-total path is parameterized by the other rel, we
1299 : * can't use a mergejoin. (There's no use looking for alternative input
1300 : * paths, since these should already be the least-parameterized available
1301 : * paths.)
1302 : */
1303 553504 : if (PATH_PARAM_BY_REL(outer_path, innerrel) ||
1304 542624 : PATH_PARAM_BY_REL(inner_path, outerrel))
1305 21808 : return;
1306 :
1307 : /*
1308 : * If unique-ification is requested, do it and then handle as a plain
1309 : * inner join.
1310 : */
1311 531696 : if (jointype == JOIN_UNIQUE_OUTER)
1312 : {
1313 4482 : outer_path = (Path *) create_unique_path(root, outerrel,
1314 : outer_path, extra->sjinfo);
1315 : Assert(outer_path);
1316 4482 : jointype = JOIN_INNER;
1317 : }
1318 527214 : else if (jointype == JOIN_UNIQUE_INNER)
1319 : {
1320 4482 : inner_path = (Path *) create_unique_path(root, innerrel,
1321 : inner_path, extra->sjinfo);
1322 : Assert(inner_path);
1323 4482 : jointype = JOIN_INNER;
1324 : }
1325 :
1326 : /*
1327 : * If the joinrel is parallel-safe, we may be able to consider a partial
1328 : * merge join. However, we can't handle JOIN_UNIQUE_OUTER, because the
1329 : * outer path will be partial, and therefore we won't be able to properly
1330 : * guarantee uniqueness. Similarly, we can't handle JOIN_FULL, JOIN_RIGHT
1331 : * and JOIN_RIGHT_ANTI, because they can produce false null extended rows.
1332 : * Also, the resulting path must not be parameterized.
1333 : */
1334 531696 : if (joinrel->consider_parallel &&
1335 461460 : save_jointype != JOIN_UNIQUE_OUTER &&
1336 458996 : save_jointype != JOIN_FULL &&
1337 378300 : save_jointype != JOIN_RIGHT &&
1338 377006 : save_jointype != JOIN_RIGHT_ANTI &&
1339 377006 : outerrel->partial_pathlist != NIL &&
1340 9838 : bms_is_empty(joinrel->lateral_relids))
1341 : {
1342 9838 : cheapest_partial_outer = (Path *) linitial(outerrel->partial_pathlist);
1343 :
1344 9838 : if (inner_path->parallel_safe)
1345 9448 : cheapest_safe_inner = inner_path;
1346 390 : else if (save_jointype != JOIN_UNIQUE_INNER)
1347 : cheapest_safe_inner =
1348 384 : get_cheapest_parallel_safe_total_inner(innerrel->pathlist);
1349 : }
1350 :
1351 : /*
1352 : * Each possible ordering of the available mergejoin clauses will generate
1353 : * a differently-sorted result path at essentially the same cost. We have
1354 : * no basis for choosing one over another at this level of joining, but
1355 : * some sort orders may be more useful than others for higher-level
1356 : * mergejoins, so it's worth considering multiple orderings.
1357 : *
1358 : * Actually, it's not quite true that every mergeclause ordering will
1359 : * generate a different path order, because some of the clauses may be
1360 : * partially redundant (refer to the same EquivalenceClasses). Therefore,
1361 : * what we do is convert the mergeclause list to a list of canonical
1362 : * pathkeys, and then consider different orderings of the pathkeys.
1363 : *
1364 : * Generating a path for *every* permutation of the pathkeys doesn't seem
1365 : * like a winning strategy; the cost in planning time is too high. For
1366 : * now, we generate one path for each pathkey, listing that pathkey first
1367 : * and the rest in random order. This should allow at least a one-clause
1368 : * mergejoin without re-sorting against any other possible mergejoin
1369 : * partner path. But if we've not guessed the right ordering of secondary
1370 : * keys, we may end up evaluating clauses as qpquals when they could have
1371 : * been done as mergeclauses. (In practice, it's rare that there's more
1372 : * than two or three mergeclauses, so expending a huge amount of thought
1373 : * on that is probably not worth it.)
1374 : *
1375 : * The pathkey order returned by select_outer_pathkeys_for_merge() has
1376 : * some heuristics behind it (see that function), so be sure to try it
1377 : * exactly as-is as well as making variants.
1378 : */
1379 531696 : all_pathkeys = select_outer_pathkeys_for_merge(root,
1380 : extra->mergeclause_list,
1381 : joinrel);
1382 :
1383 1015394 : foreach(l, all_pathkeys)
1384 : {
1385 483698 : PathKey *front_pathkey = (PathKey *) lfirst(l);
1386 : List *cur_mergeclauses;
1387 : List *outerkeys;
1388 : List *innerkeys;
1389 : List *merge_pathkeys;
1390 :
1391 : /* Make a pathkey list with this guy first */
1392 483698 : if (l != list_head(all_pathkeys))
1393 43120 : outerkeys = lcons(front_pathkey,
1394 : list_delete_nth_cell(list_copy(all_pathkeys),
1395 : foreach_current_index(l)));
1396 : else
1397 440578 : outerkeys = all_pathkeys; /* no work at first one... */
1398 :
1399 : /* Sort the mergeclauses into the corresponding ordering */
1400 : cur_mergeclauses =
1401 483698 : find_mergeclauses_for_outer_pathkeys(root,
1402 : outerkeys,
1403 : extra->mergeclause_list);
1404 :
1405 : /* Should have used them all... */
1406 : Assert(list_length(cur_mergeclauses) == list_length(extra->mergeclause_list));
1407 :
1408 : /* Build sort pathkeys for the inner side */
1409 483698 : innerkeys = make_inner_pathkeys_for_merge(root,
1410 : cur_mergeclauses,
1411 : outerkeys);
1412 :
1413 : /* Build pathkeys representing output sort order */
1414 483698 : merge_pathkeys = build_join_pathkeys(root, joinrel, jointype,
1415 : outerkeys);
1416 :
1417 : /*
1418 : * And now we can make the path.
1419 : *
1420 : * Note: it's possible that the cheapest paths will already be sorted
1421 : * properly. try_mergejoin_path will detect that case and suppress an
1422 : * explicit sort step, so we needn't do so here.
1423 : */
1424 483698 : try_mergejoin_path(root,
1425 : joinrel,
1426 : outer_path,
1427 : inner_path,
1428 : merge_pathkeys,
1429 : cur_mergeclauses,
1430 : outerkeys,
1431 : innerkeys,
1432 : jointype,
1433 : extra,
1434 : false);
1435 :
1436 : /*
1437 : * If we have partial outer and parallel safe inner path then try
1438 : * partial mergejoin path.
1439 : */
1440 483698 : if (cheapest_partial_outer && cheapest_safe_inner)
1441 12138 : try_partial_mergejoin_path(root,
1442 : joinrel,
1443 : cheapest_partial_outer,
1444 : cheapest_safe_inner,
1445 : merge_pathkeys,
1446 : cur_mergeclauses,
1447 : outerkeys,
1448 : innerkeys,
1449 : jointype,
1450 : extra);
1451 : }
1452 : }
1453 :
1454 : /*
1455 : * generate_mergejoin_paths
1456 : * Creates possible mergejoin paths for input outerpath.
1457 : *
1458 : * We generate mergejoins if mergejoin clauses are available. We have
1459 : * two ways to generate the inner path for a mergejoin: sort the cheapest
1460 : * inner path, or use an inner path that is already suitably ordered for the
1461 : * merge. If we have several mergeclauses, it could be that there is no inner
1462 : * path (or only a very expensive one) for the full list of mergeclauses, but
1463 : * better paths exist if we truncate the mergeclause list (thereby discarding
1464 : * some sort key requirements). So, we consider truncations of the
1465 : * mergeclause list as well as the full list. (Ideally we'd consider all
1466 : * subsets of the mergeclause list, but that seems way too expensive.)
1467 : */
1468 : static void
1469 1045670 : generate_mergejoin_paths(PlannerInfo *root,
1470 : RelOptInfo *joinrel,
1471 : RelOptInfo *innerrel,
1472 : Path *outerpath,
1473 : JoinType jointype,
1474 : JoinPathExtraData *extra,
1475 : bool useallclauses,
1476 : Path *inner_cheapest_total,
1477 : List *merge_pathkeys,
1478 : bool is_partial)
1479 : {
1480 : List *mergeclauses;
1481 : List *innersortkeys;
1482 : List *trialsortkeys;
1483 : Path *cheapest_startup_inner;
1484 : Path *cheapest_total_inner;
1485 1045670 : JoinType save_jointype = jointype;
1486 : int num_sortkeys;
1487 : int sortkeycnt;
1488 :
1489 1045670 : if (jointype == JOIN_UNIQUE_OUTER || jointype == JOIN_UNIQUE_INNER)
1490 9302 : jointype = JOIN_INNER;
1491 :
1492 : /* Look for useful mergeclauses (if any) */
1493 : mergeclauses =
1494 1045670 : find_mergeclauses_for_outer_pathkeys(root,
1495 : outerpath->pathkeys,
1496 : extra->mergeclause_list);
1497 :
1498 : /*
1499 : * Done with this outer path if no chance for a mergejoin.
1500 : *
1501 : * Special corner case: for "x FULL JOIN y ON true", there will be no join
1502 : * clauses at all. Ordinarily we'd generate a clauseless nestloop path,
1503 : * but since mergejoin is our only join type that supports FULL JOIN
1504 : * without any join clauses, it's necessary to generate a clauseless
1505 : * mergejoin path instead.
1506 : */
1507 1045670 : if (mergeclauses == NIL)
1508 : {
1509 700786 : if (jointype == JOIN_FULL)
1510 : /* okay to try for mergejoin */ ;
1511 : else
1512 697438 : return;
1513 : }
1514 433166 : if (useallclauses &&
1515 84934 : list_length(mergeclauses) != list_length(extra->mergeclause_list))
1516 11260 : return;
1517 :
1518 : /* Compute the required ordering of the inner path */
1519 336972 : innersortkeys = make_inner_pathkeys_for_merge(root,
1520 : mergeclauses,
1521 : outerpath->pathkeys);
1522 :
1523 : /*
1524 : * Generate a mergejoin on the basis of sorting the cheapest inner. Since
1525 : * a sort will be needed, only cheapest total cost matters. (But
1526 : * try_mergejoin_path will do the right thing if inner_cheapest_total is
1527 : * already correctly sorted.)
1528 : */
1529 336972 : try_mergejoin_path(root,
1530 : joinrel,
1531 : outerpath,
1532 : inner_cheapest_total,
1533 : merge_pathkeys,
1534 : mergeclauses,
1535 : NIL,
1536 : innersortkeys,
1537 : jointype,
1538 : extra,
1539 : is_partial);
1540 :
1541 : /* Can't do anything else if inner path needs to be unique'd */
1542 336972 : if (save_jointype == JOIN_UNIQUE_INNER)
1543 1802 : return;
1544 :
1545 : /*
1546 : * Look for presorted inner paths that satisfy the innersortkey list ---
1547 : * or any truncation thereof, if we are allowed to build a mergejoin using
1548 : * a subset of the merge clauses. Here, we consider both cheap startup
1549 : * cost and cheap total cost.
1550 : *
1551 : * Currently we do not consider parameterized inner paths here. This
1552 : * interacts with decisions elsewhere that also discriminate against
1553 : * mergejoins with parameterized inputs; see comments in
1554 : * src/backend/optimizer/README.
1555 : *
1556 : * As we shorten the sortkey list, we should consider only paths that are
1557 : * strictly cheaper than (in particular, not the same as) any path found
1558 : * in an earlier iteration. Otherwise we'd be intentionally using fewer
1559 : * merge keys than a given path allows (treating the rest as plain
1560 : * joinquals), which is unlikely to be a good idea. Also, eliminating
1561 : * paths here on the basis of compare_path_costs is a lot cheaper than
1562 : * building the mergejoin path only to throw it away.
1563 : *
1564 : * If inner_cheapest_total is well enough sorted to have not required a
1565 : * sort in the path made above, we shouldn't make a duplicate path with
1566 : * it, either. We handle that case with the same logic that handles the
1567 : * previous consideration, by initializing the variables that track
1568 : * cheapest-so-far properly. Note that we do NOT reject
1569 : * inner_cheapest_total if we find it matches some shorter set of
1570 : * pathkeys. That case corresponds to using fewer mergekeys to avoid
1571 : * sorting inner_cheapest_total, whereas we did sort it above, so the
1572 : * plans being considered are different.
1573 : */
1574 335170 : if (pathkeys_contained_in(innersortkeys,
1575 : inner_cheapest_total->pathkeys))
1576 : {
1577 : /* inner_cheapest_total didn't require a sort */
1578 10326 : cheapest_startup_inner = inner_cheapest_total;
1579 10326 : cheapest_total_inner = inner_cheapest_total;
1580 : }
1581 : else
1582 : {
1583 : /* it did require a sort, at least for the full set of keys */
1584 324844 : cheapest_startup_inner = NULL;
1585 324844 : cheapest_total_inner = NULL;
1586 : }
1587 335170 : num_sortkeys = list_length(innersortkeys);
1588 335170 : if (num_sortkeys > 1 && !useallclauses)
1589 9350 : trialsortkeys = list_copy(innersortkeys); /* need modifiable copy */
1590 : else
1591 325820 : trialsortkeys = innersortkeys; /* won't really truncate */
1592 :
1593 606152 : for (sortkeycnt = num_sortkeys; sortkeycnt > 0; sortkeycnt--)
1594 : {
1595 : Path *innerpath;
1596 344512 : List *newclauses = NIL;
1597 :
1598 : /*
1599 : * Look for an inner path ordered well enough for the first
1600 : * 'sortkeycnt' innersortkeys. NB: trialsortkeys list is modified
1601 : * destructively, which is why we made a copy...
1602 : */
1603 344512 : trialsortkeys = list_truncate(trialsortkeys, sortkeycnt);
1604 344512 : innerpath = get_cheapest_path_for_pathkeys(innerrel->pathlist,
1605 : trialsortkeys,
1606 : NULL,
1607 : TOTAL_COST,
1608 : is_partial);
1609 344512 : if (innerpath != NULL &&
1610 15320 : (cheapest_total_inner == NULL ||
1611 15320 : compare_path_costs(innerpath, cheapest_total_inner,
1612 : TOTAL_COST) < 0))
1613 : {
1614 : /* Found a cheap (or even-cheaper) sorted path */
1615 : /* Select the right mergeclauses, if we didn't already */
1616 204042 : if (sortkeycnt < num_sortkeys)
1617 : {
1618 : newclauses =
1619 2502 : trim_mergeclauses_for_inner_pathkeys(root,
1620 : mergeclauses,
1621 : trialsortkeys);
1622 : Assert(newclauses != NIL);
1623 : }
1624 : else
1625 201540 : newclauses = mergeclauses;
1626 204042 : try_mergejoin_path(root,
1627 : joinrel,
1628 : outerpath,
1629 : innerpath,
1630 : merge_pathkeys,
1631 : newclauses,
1632 : NIL,
1633 : NIL,
1634 : jointype,
1635 : extra,
1636 : is_partial);
1637 204042 : cheapest_total_inner = innerpath;
1638 : }
1639 : /* Same on the basis of cheapest startup cost ... */
1640 344512 : innerpath = get_cheapest_path_for_pathkeys(innerrel->pathlist,
1641 : trialsortkeys,
1642 : NULL,
1643 : STARTUP_COST,
1644 : is_partial);
1645 344512 : if (innerpath != NULL &&
1646 15320 : (cheapest_startup_inner == NULL ||
1647 15320 : compare_path_costs(innerpath, cheapest_startup_inner,
1648 : STARTUP_COST) < 0))
1649 : {
1650 : /* Found a cheap (or even-cheaper) sorted path */
1651 202714 : if (innerpath != cheapest_total_inner)
1652 : {
1653 : /*
1654 : * Avoid rebuilding clause list if we already made one; saves
1655 : * memory in big join trees...
1656 : */
1657 1022 : if (newclauses == NIL)
1658 : {
1659 2 : if (sortkeycnt < num_sortkeys)
1660 : {
1661 : newclauses =
1662 0 : trim_mergeclauses_for_inner_pathkeys(root,
1663 : mergeclauses,
1664 : trialsortkeys);
1665 : Assert(newclauses != NIL);
1666 : }
1667 : else
1668 2 : newclauses = mergeclauses;
1669 : }
1670 1022 : try_mergejoin_path(root,
1671 : joinrel,
1672 : outerpath,
1673 : innerpath,
1674 : merge_pathkeys,
1675 : newclauses,
1676 : NIL,
1677 : NIL,
1678 : jointype,
1679 : extra,
1680 : is_partial);
1681 : }
1682 202714 : cheapest_startup_inner = innerpath;
1683 : }
1684 :
1685 : /*
1686 : * Don't consider truncated sortkeys if we need all clauses.
1687 : */
1688 344512 : if (useallclauses)
1689 73530 : break;
1690 : }
1691 : }
1692 :
1693 : /*
1694 : * match_unsorted_outer
1695 : * Creates possible join paths for processing a single join relation
1696 : * 'joinrel' by employing either iterative substitution or
1697 : * mergejoining on each of its possible outer paths (considering
1698 : * only outer paths that are already ordered well enough for merging).
1699 : *
1700 : * We always generate a nestloop path for each available outer path.
1701 : * In fact we may generate as many as five: one on the cheapest-total-cost
1702 : * inner path, one on the same with materialization, one on the
1703 : * cheapest-startup-cost inner path (if different), one on the
1704 : * cheapest-total inner-indexscan path (if any), and one on the
1705 : * cheapest-startup inner-indexscan path (if different).
1706 : *
1707 : * We also consider mergejoins if mergejoin clauses are available. See
1708 : * detailed comments in generate_mergejoin_paths.
1709 : *
1710 : * 'joinrel' is the join relation
1711 : * 'outerrel' is the outer join relation
1712 : * 'innerrel' is the inner join relation
1713 : * 'jointype' is the type of join to do
1714 : * 'extra' contains additional input values
1715 : */
1716 : static void
1717 553504 : match_unsorted_outer(PlannerInfo *root,
1718 : RelOptInfo *joinrel,
1719 : RelOptInfo *outerrel,
1720 : RelOptInfo *innerrel,
1721 : JoinType jointype,
1722 : JoinPathExtraData *extra)
1723 : {
1724 553504 : JoinType save_jointype = jointype;
1725 : bool nestjoinOK;
1726 : bool useallclauses;
1727 553504 : Path *inner_cheapest_total = innerrel->cheapest_total_path;
1728 553504 : Path *matpath = NULL;
1729 : ListCell *lc1;
1730 :
1731 : /*
1732 : * Nestloop only supports inner, left, semi, and anti joins. Also, if we
1733 : * are doing a right, right-anti or full mergejoin, we must use *all* the
1734 : * mergeclauses as join clauses, else we will not have a valid plan.
1735 : * (Although these two flags are currently inverses, keep them separate
1736 : * for clarity and possible future changes.)
1737 : */
1738 553504 : switch (jointype)
1739 : {
1740 452486 : case JOIN_INNER:
1741 : case JOIN_LEFT:
1742 : case JOIN_SEMI:
1743 : case JOIN_ANTI:
1744 452486 : nestjoinOK = true;
1745 452486 : useallclauses = false;
1746 452486 : break;
1747 92030 : case JOIN_RIGHT:
1748 : case JOIN_RIGHT_ANTI:
1749 : case JOIN_FULL:
1750 92030 : nestjoinOK = false;
1751 92030 : useallclauses = true;
1752 92030 : break;
1753 8988 : case JOIN_UNIQUE_OUTER:
1754 : case JOIN_UNIQUE_INNER:
1755 8988 : jointype = JOIN_INNER;
1756 8988 : nestjoinOK = true;
1757 8988 : useallclauses = false;
1758 8988 : break;
1759 0 : default:
1760 0 : elog(ERROR, "unrecognized join type: %d",
1761 : (int) jointype);
1762 : nestjoinOK = false; /* keep compiler quiet */
1763 : useallclauses = false;
1764 : break;
1765 : }
1766 :
1767 : /*
1768 : * If inner_cheapest_total is parameterized by the outer rel, ignore it;
1769 : * we will consider it below as a member of cheapest_parameterized_paths,
1770 : * but the other possibilities considered in this routine aren't usable.
1771 : */
1772 553504 : if (PATH_PARAM_BY_REL(inner_cheapest_total, outerrel))
1773 10928 : inner_cheapest_total = NULL;
1774 :
1775 : /*
1776 : * If we need to unique-ify the inner path, we will consider only the
1777 : * cheapest-total inner.
1778 : */
1779 553504 : if (save_jointype == JOIN_UNIQUE_INNER)
1780 : {
1781 : /* No way to do this with an inner path parameterized by outer rel */
1782 4494 : if (inner_cheapest_total == NULL)
1783 12 : return;
1784 : inner_cheapest_total = (Path *)
1785 4482 : create_unique_path(root, innerrel, inner_cheapest_total, extra->sjinfo);
1786 : Assert(inner_cheapest_total);
1787 : }
1788 549010 : else if (nestjoinOK)
1789 : {
1790 : /*
1791 : * Consider materializing the cheapest inner path, unless
1792 : * enable_material is off or the path in question materializes its
1793 : * output anyway.
1794 : */
1795 456980 : if (enable_material && inner_cheapest_total != NULL &&
1796 445638 : !ExecMaterializesOutput(inner_cheapest_total->pathtype))
1797 : matpath = (Path *)
1798 424578 : create_material_path(innerrel, inner_cheapest_total);
1799 : }
1800 :
1801 1814540 : foreach(lc1, outerrel->pathlist)
1802 : {
1803 1261048 : Path *outerpath = (Path *) lfirst(lc1);
1804 : List *merge_pathkeys;
1805 :
1806 : /*
1807 : * We cannot use an outer path that is parameterized by the inner rel.
1808 : */
1809 1261048 : if (PATH_PARAM_BY_REL(outerpath, innerrel))
1810 211672 : continue;
1811 :
1812 : /*
1813 : * If we need to unique-ify the outer path, it's pointless to consider
1814 : * any but the cheapest outer. (XXX we don't consider parameterized
1815 : * outers, nor inners, for unique-ified cases. Should we?)
1816 : */
1817 1049376 : if (save_jointype == JOIN_UNIQUE_OUTER)
1818 : {
1819 5642 : if (outerpath != outerrel->cheapest_total_path)
1820 1160 : continue;
1821 4482 : outerpath = (Path *) create_unique_path(root, outerrel,
1822 : outerpath, extra->sjinfo);
1823 : Assert(outerpath);
1824 : }
1825 :
1826 : /*
1827 : * The result will have this sort order (even if it is implemented as
1828 : * a nestloop, and even if some of the mergeclauses are implemented by
1829 : * qpquals rather than as true mergeclauses):
1830 : */
1831 1048216 : merge_pathkeys = build_join_pathkeys(root, joinrel, jointype,
1832 : outerpath->pathkeys);
1833 :
1834 1048216 : if (save_jointype == JOIN_UNIQUE_INNER)
1835 : {
1836 : /*
1837 : * Consider nestloop join, but only with the unique-ified cheapest
1838 : * inner path
1839 : */
1840 8450 : try_nestloop_path(root,
1841 : joinrel,
1842 : outerpath,
1843 : inner_cheapest_total,
1844 : merge_pathkeys,
1845 : jointype,
1846 : extra);
1847 : }
1848 1039766 : else if (nestjoinOK)
1849 : {
1850 : /*
1851 : * Consider nestloop joins using this outer path and various
1852 : * available paths for the inner relation. We consider the
1853 : * cheapest-total paths for each available parameterization of the
1854 : * inner relation, including the unparameterized case.
1855 : */
1856 : ListCell *lc2;
1857 :
1858 2268704 : foreach(lc2, innerrel->cheapest_parameterized_paths)
1859 : {
1860 1406604 : Path *innerpath = (Path *) lfirst(lc2);
1861 : Path *mpath;
1862 :
1863 1406604 : try_nestloop_path(root,
1864 : joinrel,
1865 : outerpath,
1866 : innerpath,
1867 : merge_pathkeys,
1868 : jointype,
1869 : extra);
1870 :
1871 : /*
1872 : * Try generating a memoize path and see if that makes the
1873 : * nested loop any cheaper.
1874 : */
1875 1406604 : mpath = get_memoize_path(root, innerrel, outerrel,
1876 : innerpath, outerpath, jointype,
1877 : extra);
1878 1406604 : if (mpath != NULL)
1879 237010 : try_nestloop_path(root,
1880 : joinrel,
1881 : outerpath,
1882 : mpath,
1883 : merge_pathkeys,
1884 : jointype,
1885 : extra);
1886 : }
1887 :
1888 : /* Also consider materialized form of the cheapest inner path */
1889 862100 : if (matpath != NULL)
1890 809922 : try_nestloop_path(root,
1891 : joinrel,
1892 : outerpath,
1893 : matpath,
1894 : merge_pathkeys,
1895 : jointype,
1896 : extra);
1897 : }
1898 :
1899 : /* Can't do anything else if outer path needs to be unique'd */
1900 1048216 : if (save_jointype == JOIN_UNIQUE_OUTER)
1901 4482 : continue;
1902 :
1903 : /* Can't do anything else if inner rel is parameterized by outer */
1904 1043734 : if (inner_cheapest_total == NULL)
1905 11364 : continue;
1906 :
1907 : /* Generate merge join paths */
1908 1032370 : generate_mergejoin_paths(root, joinrel, innerrel, outerpath,
1909 : save_jointype, extra, useallclauses,
1910 : inner_cheapest_total, merge_pathkeys,
1911 : false);
1912 : }
1913 :
1914 : /*
1915 : * Consider partial nestloop and mergejoin plan if outerrel has any
1916 : * partial path and the joinrel is parallel-safe. However, we can't
1917 : * handle JOIN_UNIQUE_OUTER, because the outer path will be partial, and
1918 : * therefore we won't be able to properly guarantee uniqueness. Nor can
1919 : * we handle joins needing lateral rels, since partial paths must not be
1920 : * parameterized. Similarly, we can't handle JOIN_FULL, JOIN_RIGHT and
1921 : * JOIN_RIGHT_ANTI, because they can produce false null extended rows.
1922 : */
1923 553492 : if (joinrel->consider_parallel &&
1924 466742 : save_jointype != JOIN_UNIQUE_OUTER &&
1925 464278 : save_jointype != JOIN_FULL &&
1926 383264 : save_jointype != JOIN_RIGHT &&
1927 381970 : save_jointype != JOIN_RIGHT_ANTI &&
1928 381970 : outerrel->partial_pathlist != NIL &&
1929 10240 : bms_is_empty(joinrel->lateral_relids))
1930 : {
1931 10240 : if (nestjoinOK)
1932 10240 : consider_parallel_nestloop(root, joinrel, outerrel, innerrel,
1933 : save_jointype, extra);
1934 :
1935 : /*
1936 : * If inner_cheapest_total is NULL or non parallel-safe then find the
1937 : * cheapest total parallel safe path. If doing JOIN_UNIQUE_INNER, we
1938 : * can't use any alternative inner path.
1939 : */
1940 10240 : if (inner_cheapest_total == NULL ||
1941 9838 : !inner_cheapest_total->parallel_safe)
1942 : {
1943 792 : if (save_jointype == JOIN_UNIQUE_INNER)
1944 6 : return;
1945 :
1946 786 : inner_cheapest_total = get_cheapest_parallel_safe_total_inner(innerrel->pathlist);
1947 : }
1948 :
1949 10234 : if (inner_cheapest_total)
1950 9814 : consider_parallel_mergejoin(root, joinrel, outerrel, innerrel,
1951 : save_jointype, extra,
1952 : inner_cheapest_total);
1953 : }
1954 : }
1955 :
1956 : /*
1957 : * consider_parallel_mergejoin
1958 : * Try to build partial paths for a joinrel by joining a partial path
1959 : * for the outer relation to a complete path for the inner relation.
1960 : *
1961 : * 'joinrel' is the join relation
1962 : * 'outerrel' is the outer join relation
1963 : * 'innerrel' is the inner join relation
1964 : * 'jointype' is the type of join to do
1965 : * 'extra' contains additional input values
1966 : * 'inner_cheapest_total' cheapest total path for innerrel
1967 : */
1968 : static void
1969 9814 : consider_parallel_mergejoin(PlannerInfo *root,
1970 : RelOptInfo *joinrel,
1971 : RelOptInfo *outerrel,
1972 : RelOptInfo *innerrel,
1973 : JoinType jointype,
1974 : JoinPathExtraData *extra,
1975 : Path *inner_cheapest_total)
1976 : {
1977 : ListCell *lc1;
1978 :
1979 : /* generate merge join path for each partial outer path */
1980 23114 : foreach(lc1, outerrel->partial_pathlist)
1981 : {
1982 13300 : Path *outerpath = (Path *) lfirst(lc1);
1983 : List *merge_pathkeys;
1984 :
1985 : /*
1986 : * Figure out what useful ordering any paths we create will have.
1987 : */
1988 13300 : merge_pathkeys = build_join_pathkeys(root, joinrel, jointype,
1989 : outerpath->pathkeys);
1990 :
1991 13300 : generate_mergejoin_paths(root, joinrel, innerrel, outerpath, jointype,
1992 : extra, false, inner_cheapest_total,
1993 : merge_pathkeys, true);
1994 : }
1995 9814 : }
1996 :
1997 : /*
1998 : * consider_parallel_nestloop
1999 : * Try to build partial paths for a joinrel by joining a partial path for the
2000 : * outer relation to a complete path for the inner relation.
2001 : *
2002 : * 'joinrel' is the join relation
2003 : * 'outerrel' is the outer join relation
2004 : * 'innerrel' is the inner join relation
2005 : * 'jointype' is the type of join to do
2006 : * 'extra' contains additional input values
2007 : */
2008 : static void
2009 10240 : consider_parallel_nestloop(PlannerInfo *root,
2010 : RelOptInfo *joinrel,
2011 : RelOptInfo *outerrel,
2012 : RelOptInfo *innerrel,
2013 : JoinType jointype,
2014 : JoinPathExtraData *extra)
2015 : {
2016 10240 : JoinType save_jointype = jointype;
2017 : ListCell *lc1;
2018 :
2019 10240 : if (jointype == JOIN_UNIQUE_INNER)
2020 570 : jointype = JOIN_INNER;
2021 :
2022 24104 : foreach(lc1, outerrel->partial_pathlist)
2023 : {
2024 13864 : Path *outerpath = (Path *) lfirst(lc1);
2025 : List *pathkeys;
2026 : ListCell *lc2;
2027 :
2028 : /* Figure out what useful ordering any paths we create will have. */
2029 13864 : pathkeys = build_join_pathkeys(root, joinrel, jointype,
2030 : outerpath->pathkeys);
2031 :
2032 : /*
2033 : * Try the cheapest parameterized paths; only those which will produce
2034 : * an unparameterized path when joined to this outerrel will survive
2035 : * try_partial_nestloop_path. The cheapest unparameterized path is
2036 : * also in this list.
2037 : */
2038 36122 : foreach(lc2, innerrel->cheapest_parameterized_paths)
2039 : {
2040 22258 : Path *innerpath = (Path *) lfirst(lc2);
2041 : Path *mpath;
2042 :
2043 : /* Can't join to an inner path that is not parallel-safe */
2044 22258 : if (!innerpath->parallel_safe)
2045 438 : continue;
2046 :
2047 : /*
2048 : * If we're doing JOIN_UNIQUE_INNER, we can only use the inner's
2049 : * cheapest_total_path, and we have to unique-ify it. (We might
2050 : * be able to relax this to allow other safe, unparameterized
2051 : * inner paths, but right now create_unique_path is not on board
2052 : * with that.)
2053 : */
2054 21820 : if (save_jointype == JOIN_UNIQUE_INNER)
2055 : {
2056 1734 : if (innerpath != innerrel->cheapest_total_path)
2057 882 : continue;
2058 852 : innerpath = (Path *) create_unique_path(root, innerrel,
2059 : innerpath,
2060 : extra->sjinfo);
2061 : Assert(innerpath);
2062 : }
2063 :
2064 20938 : try_partial_nestloop_path(root, joinrel, outerpath, innerpath,
2065 : pathkeys, jointype, extra);
2066 :
2067 : /*
2068 : * Try generating a memoize path and see if that makes the nested
2069 : * loop any cheaper.
2070 : */
2071 20938 : mpath = get_memoize_path(root, innerrel, outerrel,
2072 : innerpath, outerpath, jointype,
2073 : extra);
2074 20938 : if (mpath != NULL)
2075 5274 : try_partial_nestloop_path(root, joinrel, outerpath, mpath,
2076 : pathkeys, jointype, extra);
2077 : }
2078 : }
2079 10240 : }
2080 :
2081 : /*
2082 : * hash_inner_and_outer
2083 : * Create hashjoin join paths by explicitly hashing both the outer and
2084 : * inner keys of each available hash clause.
2085 : *
2086 : * 'joinrel' is the join relation
2087 : * 'outerrel' is the outer join relation
2088 : * 'innerrel' is the inner join relation
2089 : * 'jointype' is the type of join to do
2090 : * 'extra' contains additional input values
2091 : */
2092 : static void
2093 557014 : hash_inner_and_outer(PlannerInfo *root,
2094 : RelOptInfo *joinrel,
2095 : RelOptInfo *outerrel,
2096 : RelOptInfo *innerrel,
2097 : JoinType jointype,
2098 : JoinPathExtraData *extra)
2099 : {
2100 557014 : JoinType save_jointype = jointype;
2101 557014 : bool isouterjoin = IS_OUTER_JOIN(jointype);
2102 : List *hashclauses;
2103 : ListCell *l;
2104 :
2105 : /*
2106 : * We need to build only one hashclauses list for any given pair of outer
2107 : * and inner relations; all of the hashable clauses will be used as keys.
2108 : *
2109 : * Scan the join's restrictinfo list to find hashjoinable clauses that are
2110 : * usable with this pair of sub-relations.
2111 : */
2112 557014 : hashclauses = NIL;
2113 1138266 : foreach(l, extra->restrictlist)
2114 : {
2115 581252 : RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(l);
2116 :
2117 : /*
2118 : * If processing an outer join, only use its own join clauses for
2119 : * hashing. For inner joins we need not be so picky.
2120 : */
2121 581252 : if (isouterjoin && RINFO_IS_PUSHED_DOWN(restrictinfo, joinrel->relids))
2122 8976 : continue;
2123 :
2124 572276 : if (!restrictinfo->can_join ||
2125 510622 : restrictinfo->hashjoinoperator == InvalidOid)
2126 80408 : continue; /* not hashjoinable */
2127 :
2128 : /*
2129 : * Check if clause has the form "outer op inner" or "inner op outer".
2130 : */
2131 491868 : if (!clause_sides_match_join(restrictinfo, outerrel, innerrel))
2132 144 : continue; /* no good for these input relations */
2133 :
2134 491724 : hashclauses = lappend(hashclauses, restrictinfo);
2135 : }
2136 :
2137 : /* If we found any usable hashclauses, make paths */
2138 557014 : if (hashclauses)
2139 : {
2140 : /*
2141 : * We consider both the cheapest-total-cost and cheapest-startup-cost
2142 : * outer paths. There's no need to consider any but the
2143 : * cheapest-total-cost inner path, however.
2144 : */
2145 448032 : Path *cheapest_startup_outer = outerrel->cheapest_startup_path;
2146 448032 : Path *cheapest_total_outer = outerrel->cheapest_total_path;
2147 448032 : Path *cheapest_total_inner = innerrel->cheapest_total_path;
2148 :
2149 : /*
2150 : * If either cheapest-total path is parameterized by the other rel, we
2151 : * can't use a hashjoin. (There's no use looking for alternative
2152 : * input paths, since these should already be the least-parameterized
2153 : * available paths.)
2154 : */
2155 448032 : if (PATH_PARAM_BY_REL(cheapest_total_outer, innerrel) ||
2156 447368 : PATH_PARAM_BY_REL(cheapest_total_inner, outerrel))
2157 1340 : return;
2158 :
2159 : /* Unique-ify if need be; we ignore parameterized possibilities */
2160 446692 : if (jointype == JOIN_UNIQUE_OUTER)
2161 : {
2162 : cheapest_total_outer = (Path *)
2163 2622 : create_unique_path(root, outerrel,
2164 : cheapest_total_outer, extra->sjinfo);
2165 : Assert(cheapest_total_outer);
2166 2622 : jointype = JOIN_INNER;
2167 2622 : try_hashjoin_path(root,
2168 : joinrel,
2169 : cheapest_total_outer,
2170 : cheapest_total_inner,
2171 : hashclauses,
2172 : jointype,
2173 : extra);
2174 : /* no possibility of cheap startup here */
2175 : }
2176 444070 : else if (jointype == JOIN_UNIQUE_INNER)
2177 : {
2178 : cheapest_total_inner = (Path *)
2179 2622 : create_unique_path(root, innerrel,
2180 : cheapest_total_inner, extra->sjinfo);
2181 : Assert(cheapest_total_inner);
2182 2622 : jointype = JOIN_INNER;
2183 2622 : try_hashjoin_path(root,
2184 : joinrel,
2185 : cheapest_total_outer,
2186 : cheapest_total_inner,
2187 : hashclauses,
2188 : jointype,
2189 : extra);
2190 2622 : if (cheapest_startup_outer != NULL &&
2191 : cheapest_startup_outer != cheapest_total_outer)
2192 324 : try_hashjoin_path(root,
2193 : joinrel,
2194 : cheapest_startup_outer,
2195 : cheapest_total_inner,
2196 : hashclauses,
2197 : jointype,
2198 : extra);
2199 : }
2200 : else
2201 : {
2202 : /*
2203 : * For other jointypes, we consider the cheapest startup outer
2204 : * together with the cheapest total inner, and then consider
2205 : * pairings of cheapest-total paths including parameterized ones.
2206 : * There is no use in generating parameterized paths on the basis
2207 : * of possibly cheap startup cost, so this is sufficient.
2208 : */
2209 : ListCell *lc1;
2210 : ListCell *lc2;
2211 :
2212 441448 : if (cheapest_startup_outer != NULL)
2213 440830 : try_hashjoin_path(root,
2214 : joinrel,
2215 : cheapest_startup_outer,
2216 : cheapest_total_inner,
2217 : hashclauses,
2218 : jointype,
2219 : extra);
2220 :
2221 1127884 : foreach(lc1, outerrel->cheapest_parameterized_paths)
2222 : {
2223 686436 : Path *outerpath = (Path *) lfirst(lc1);
2224 :
2225 : /*
2226 : * We cannot use an outer path that is parameterized by the
2227 : * inner rel.
2228 : */
2229 686436 : if (PATH_PARAM_BY_REL(outerpath, innerrel))
2230 203708 : continue;
2231 :
2232 1244292 : foreach(lc2, innerrel->cheapest_parameterized_paths)
2233 : {
2234 761564 : Path *innerpath = (Path *) lfirst(lc2);
2235 :
2236 : /*
2237 : * We cannot use an inner path that is parameterized by
2238 : * the outer rel, either.
2239 : */
2240 761564 : if (PATH_PARAM_BY_REL(innerpath, outerrel))
2241 227340 : continue;
2242 :
2243 534224 : if (outerpath == cheapest_startup_outer &&
2244 : innerpath == cheapest_total_inner)
2245 380086 : continue; /* already tried it */
2246 :
2247 154138 : try_hashjoin_path(root,
2248 : joinrel,
2249 : outerpath,
2250 : innerpath,
2251 : hashclauses,
2252 : jointype,
2253 : extra);
2254 : }
2255 : }
2256 : }
2257 :
2258 : /*
2259 : * If the joinrel is parallel-safe, we may be able to consider a
2260 : * partial hash join. However, we can't handle JOIN_UNIQUE_OUTER,
2261 : * because the outer path will be partial, and therefore we won't be
2262 : * able to properly guarantee uniqueness. Also, the resulting path
2263 : * must not be parameterized.
2264 : */
2265 446692 : if (joinrel->consider_parallel &&
2266 399732 : save_jointype != JOIN_UNIQUE_OUTER &&
2267 399732 : outerrel->partial_pathlist != NIL &&
2268 12678 : bms_is_empty(joinrel->lateral_relids))
2269 : {
2270 : Path *cheapest_partial_outer;
2271 12678 : Path *cheapest_partial_inner = NULL;
2272 12678 : Path *cheapest_safe_inner = NULL;
2273 :
2274 12678 : cheapest_partial_outer =
2275 12678 : (Path *) linitial(outerrel->partial_pathlist);
2276 :
2277 : /*
2278 : * Can we use a partial inner plan too, so that we can build a
2279 : * shared hash table in parallel? We can't handle
2280 : * JOIN_UNIQUE_INNER because we can't guarantee uniqueness.
2281 : */
2282 12678 : if (innerrel->partial_pathlist != NIL &&
2283 11850 : save_jointype != JOIN_UNIQUE_INNER &&
2284 : enable_parallel_hash)
2285 : {
2286 11574 : cheapest_partial_inner =
2287 11574 : (Path *) linitial(innerrel->partial_pathlist);
2288 11574 : try_partial_hashjoin_path(root, joinrel,
2289 : cheapest_partial_outer,
2290 : cheapest_partial_inner,
2291 : hashclauses, jointype, extra,
2292 : true /* parallel_hash */ );
2293 : }
2294 :
2295 : /*
2296 : * Normally, given that the joinrel is parallel-safe, the cheapest
2297 : * total inner path will also be parallel-safe, but if not, we'll
2298 : * have to search for the cheapest safe, unparameterized inner
2299 : * path. If doing JOIN_UNIQUE_INNER, we can't use any alternative
2300 : * inner path. If full, right, or right-anti join, we can't use
2301 : * parallelism (building the hash table in each backend) because
2302 : * no one process has all the match bits.
2303 : */
2304 12678 : if (save_jointype == JOIN_FULL ||
2305 8862 : save_jointype == JOIN_RIGHT ||
2306 : save_jointype == JOIN_RIGHT_ANTI)
2307 4146 : cheapest_safe_inner = NULL;
2308 8532 : else if (cheapest_total_inner->parallel_safe)
2309 8304 : cheapest_safe_inner = cheapest_total_inner;
2310 228 : else if (save_jointype != JOIN_UNIQUE_INNER)
2311 : cheapest_safe_inner =
2312 222 : get_cheapest_parallel_safe_total_inner(innerrel->pathlist);
2313 :
2314 12678 : if (cheapest_safe_inner != NULL)
2315 8520 : try_partial_hashjoin_path(root, joinrel,
2316 : cheapest_partial_outer,
2317 : cheapest_safe_inner,
2318 : hashclauses, jointype, extra,
2319 : false /* parallel_hash */ );
2320 : }
2321 : }
2322 : }
2323 :
2324 : /*
2325 : * select_mergejoin_clauses
2326 : * Select mergejoin clauses that are usable for a particular join.
2327 : * Returns a list of RestrictInfo nodes for those clauses.
2328 : *
2329 : * *mergejoin_allowed is normally set to true, but it is set to false if
2330 : * this is a right/right-anti/full join and there are nonmergejoinable join
2331 : * clauses. The executor's mergejoin machinery cannot handle such cases, so
2332 : * we have to avoid generating a mergejoin plan. (Note that this flag does
2333 : * NOT consider whether there are actually any mergejoinable clauses. This is
2334 : * correct because in some cases we need to build a clauseless mergejoin.
2335 : * Simply returning NIL is therefore not enough to distinguish safe from
2336 : * unsafe cases.)
2337 : *
2338 : * We also mark each selected RestrictInfo to show which side is currently
2339 : * being considered as outer. These are transient markings that are only
2340 : * good for the duration of the current add_paths_to_joinrel() call!
2341 : *
2342 : * We examine each restrictinfo clause known for the join to see
2343 : * if it is mergejoinable and involves vars from the two sub-relations
2344 : * currently of interest.
2345 : */
2346 : static List *
2347 558456 : select_mergejoin_clauses(PlannerInfo *root,
2348 : RelOptInfo *joinrel,
2349 : RelOptInfo *outerrel,
2350 : RelOptInfo *innerrel,
2351 : List *restrictlist,
2352 : JoinType jointype,
2353 : bool *mergejoin_allowed)
2354 : {
2355 558456 : List *result_list = NIL;
2356 558456 : bool isouterjoin = IS_OUTER_JOIN(jointype);
2357 558456 : bool have_nonmergeable_joinclause = false;
2358 : ListCell *l;
2359 :
2360 1141158 : foreach(l, restrictlist)
2361 : {
2362 582702 : RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(l);
2363 :
2364 : /*
2365 : * If processing an outer join, only use its own join clauses in the
2366 : * merge. For inner joins we can use pushed-down clauses too. (Note:
2367 : * we don't set have_nonmergeable_joinclause here because pushed-down
2368 : * clauses will become otherquals not joinquals.)
2369 : */
2370 582702 : if (isouterjoin && RINFO_IS_PUSHED_DOWN(restrictinfo, joinrel->relids))
2371 9000 : continue;
2372 :
2373 : /* Check that clause is a mergeable operator clause */
2374 573702 : if (!restrictinfo->can_join ||
2375 512048 : restrictinfo->mergeopfamilies == NIL)
2376 : {
2377 : /*
2378 : * The executor can handle extra joinquals that are constants, but
2379 : * not anything else, when doing right/right-anti/full merge join.
2380 : * (The reason to support constants is so we can do FULL JOIN ON
2381 : * FALSE.)
2382 : */
2383 79296 : if (!restrictinfo->clause || !IsA(restrictinfo->clause, Const))
2384 70116 : have_nonmergeable_joinclause = true;
2385 79296 : continue; /* not mergejoinable */
2386 : }
2387 :
2388 : /*
2389 : * Check if clause has the form "outer op inner" or "inner op outer".
2390 : */
2391 494406 : if (!clause_sides_match_join(restrictinfo, outerrel, innerrel))
2392 : {
2393 768 : have_nonmergeable_joinclause = true;
2394 768 : continue; /* no good for these input relations */
2395 : }
2396 :
2397 : /*
2398 : * Insist that each side have a non-redundant eclass. This
2399 : * restriction is needed because various bits of the planner expect
2400 : * that each clause in a merge be associable with some pathkey in a
2401 : * canonical pathkey list, but redundant eclasses can't appear in
2402 : * canonical sort orderings. (XXX it might be worth relaxing this,
2403 : * but not enough time to address it for 8.3.)
2404 : */
2405 493638 : update_mergeclause_eclasses(root, restrictinfo);
2406 :
2407 493638 : if (EC_MUST_BE_REDUNDANT(restrictinfo->left_ec) ||
2408 493590 : EC_MUST_BE_REDUNDANT(restrictinfo->right_ec))
2409 : {
2410 128 : have_nonmergeable_joinclause = true;
2411 128 : continue; /* can't handle redundant eclasses */
2412 : }
2413 :
2414 493510 : result_list = lappend(result_list, restrictinfo);
2415 : }
2416 :
2417 : /*
2418 : * Report whether mergejoin is allowed (see comment at top of function).
2419 : */
2420 558456 : switch (jointype)
2421 : {
2422 100182 : case JOIN_RIGHT:
2423 : case JOIN_RIGHT_ANTI:
2424 : case JOIN_FULL:
2425 100182 : *mergejoin_allowed = !have_nonmergeable_joinclause;
2426 100182 : break;
2427 458274 : default:
2428 458274 : *mergejoin_allowed = true;
2429 458274 : break;
2430 : }
2431 :
2432 558456 : return result_list;
2433 : }
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