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1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * joinpath.c
4 : : * Routines to find all possible paths for processing a set of joins
5 : : *
6 : : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
7 : : * Portions Copyright (c) 1994, Regents of the University of California
8 : : *
9 : : *
10 : : * IDENTIFICATION
11 : : * src/backend/optimizer/path/joinpath.c
12 : : *
13 : : *-------------------------------------------------------------------------
14 : : */
15 : : #include "postgres.h"
16 : :
17 : : #include "executor/executor.h"
18 : : #include "foreign/fdwapi.h"
19 : : #include "nodes/nodeFuncs.h"
20 : : #include "optimizer/cost.h"
21 : : #include "optimizer/optimizer.h"
22 : : #include "optimizer/pathnode.h"
23 : : #include "optimizer/paths.h"
24 : : #include "optimizer/placeholder.h"
25 : : #include "optimizer/planmain.h"
26 : : #include "optimizer/restrictinfo.h"
27 : : #include "utils/lsyscache.h"
28 : : #include "utils/typcache.h"
29 : :
30 : : /* Hooks for plugins to get control in add_paths_to_joinrel() */
31 : : set_join_pathlist_hook_type set_join_pathlist_hook = NULL;
32 : : join_path_setup_hook_type join_path_setup_hook = NULL;
33 : :
34 : : /*
35 : : * Paths parameterized by a parent rel can be considered to be parameterized
36 : : * by any of its children, when we are performing partitionwise joins. These
37 : : * macros simplify checking for such cases. Beware multiple eval of args.
38 : : */
39 : : #define PATH_PARAM_BY_PARENT(path, rel) \
40 : : ((path)->param_info && bms_overlap(PATH_REQ_OUTER(path), \
41 : : (rel)->top_parent_relids))
42 : : #define PATH_PARAM_BY_REL_SELF(path, rel) \
43 : : ((path)->param_info && bms_overlap(PATH_REQ_OUTER(path), (rel)->relids))
44 : :
45 : : #define PATH_PARAM_BY_REL(path, rel) \
46 : : (PATH_PARAM_BY_REL_SELF(path, rel) || PATH_PARAM_BY_PARENT(path, rel))
47 : :
48 : : static void try_partial_mergejoin_path(PlannerInfo *root,
49 : : RelOptInfo *joinrel,
50 : : Path *outer_path,
51 : : Path *inner_path,
52 : : List *pathkeys,
53 : : List *mergeclauses,
54 : : List *outersortkeys,
55 : : List *innersortkeys,
56 : : JoinType jointype,
57 : : JoinPathExtraData *extra);
58 : : static void sort_inner_and_outer(PlannerInfo *root, RelOptInfo *joinrel,
59 : : RelOptInfo *outerrel, RelOptInfo *innerrel,
60 : : JoinType jointype, JoinPathExtraData *extra);
61 : : static void match_unsorted_outer(PlannerInfo *root, RelOptInfo *joinrel,
62 : : RelOptInfo *outerrel, RelOptInfo *innerrel,
63 : : JoinType jointype, JoinPathExtraData *extra);
64 : : static void consider_parallel_nestloop(PlannerInfo *root,
65 : : RelOptInfo *joinrel,
66 : : RelOptInfo *outerrel,
67 : : RelOptInfo *innerrel,
68 : : JoinType jointype,
69 : : JoinPathExtraData *extra);
70 : : static void consider_parallel_mergejoin(PlannerInfo *root,
71 : : RelOptInfo *joinrel,
72 : : RelOptInfo *outerrel,
73 : : RelOptInfo *innerrel,
74 : : JoinType jointype,
75 : : JoinPathExtraData *extra,
76 : : Path *inner_cheapest_total);
77 : : static void hash_inner_and_outer(PlannerInfo *root, RelOptInfo *joinrel,
78 : : RelOptInfo *outerrel, RelOptInfo *innerrel,
79 : : JoinType jointype, JoinPathExtraData *extra);
80 : : static List *select_mergejoin_clauses(PlannerInfo *root,
81 : : RelOptInfo *joinrel,
82 : : RelOptInfo *outerrel,
83 : : RelOptInfo *innerrel,
84 : : List *restrictlist,
85 : : JoinType jointype,
86 : : bool *mergejoin_allowed);
87 : : static void generate_mergejoin_paths(PlannerInfo *root,
88 : : RelOptInfo *joinrel,
89 : : RelOptInfo *innerrel,
90 : : Path *outerpath,
91 : : JoinType jointype,
92 : : JoinPathExtraData *extra,
93 : : bool useallclauses,
94 : : Path *inner_cheapest_total,
95 : : List *merge_pathkeys,
96 : : bool is_partial);
97 : :
98 : :
99 : : /*
100 : : * add_paths_to_joinrel
101 : : * Given a join relation and two component rels from which it can be made,
102 : : * consider all possible paths that use the two component rels as outer
103 : : * and inner rel respectively. Add these paths to the join rel's pathlist
104 : : * if they survive comparison with other paths (and remove any existing
105 : : * paths that are dominated by these paths).
106 : : *
107 : : * Modifies the pathlist field of the joinrel node to contain the best
108 : : * paths found so far.
109 : : *
110 : : * jointype is not necessarily the same as sjinfo->jointype; it might be
111 : : * "flipped around" if we are considering joining the rels in the opposite
112 : : * direction from what's indicated in sjinfo.
113 : : *
114 : : * Also, this routine accepts the special JoinTypes JOIN_UNIQUE_OUTER and
115 : : * JOIN_UNIQUE_INNER to indicate that the outer or inner relation has been
116 : : * unique-ified and a regular inner join should then be applied. These values
117 : : * are not allowed to propagate outside this routine, however. Path cost
118 : : * estimation code, as well as match_unsorted_outer, may need to recognize that
119 : : * it's dealing with such a case --- the combination of nominal jointype INNER
120 : : * with sjinfo->jointype == JOIN_SEMI indicates that.
121 : : */
122 : : void
123 : 623808 : add_paths_to_joinrel(PlannerInfo *root,
124 : : RelOptInfo *joinrel,
125 : : RelOptInfo *outerrel,
126 : : RelOptInfo *innerrel,
127 : : JoinType jointype,
128 : : SpecialJoinInfo *sjinfo,
129 : : List *restrictlist)
130 : : {
131 : 623808 : JoinType save_jointype = jointype;
132 : : JoinPathExtraData extra;
133 : 623808 : 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 [ + + ]: 623808 : if (joinrel->reloptkind == RELOPT_OTHER_JOINREL)
145 : 54278 : joinrelids = joinrel->top_parent_relids;
146 : : else
147 : 569530 : joinrelids = joinrel->relids;
148 : :
149 : 623808 : extra.restrictlist = restrictlist;
150 : 623808 : extra.mergeclause_list = NIL;
151 : 623808 : extra.sjinfo = sjinfo;
152 : 623808 : extra.param_source_rels = NULL;
153 : 623808 : extra.pgs_mask = joinrel->pgs_mask;
154 : :
155 : : /*
156 : : * Give extensions a chance to take control. In particular, an extension
157 : : * might want to modify extra.pgs_mask. It's possible to override pgs_mask
158 : : * on a query-wide basis using join_search_hook, or for a particular
159 : : * relation using joinrel_setup_hook, but extensions that want to provide
160 : : * different advice for the same joinrel based on the choice of innerrel
161 : : * and outerrel will need to use this hook.
162 : : *
163 : : * A very simple way for an extension to use this hook is to set
164 : : * extra.pgs_mask &= ~PGS_JOIN_ANY, if it simply doesn't want any of the
165 : : * paths generated by this call to add_paths_to_joinrel() to be selected.
166 : : * An extension could use this technique to constrain the join order,
167 : : * since it could thereby arrange to reject all paths from join orders
168 : : * that it does not like. An extension can also selectively clear bits
169 : : * from extra.pgs_mask to rule out specific techniques for specific joins,
170 : : * or could even set additional bits to re-allow methods disabled at some
171 : : * higher level.
172 : : *
173 : : * NB: Below this point, this function should be careful to reference
174 : : * extra.pgs_mask rather than rel->pgs_mask to avoid disregarding any
175 : : * changes made by the hook we're about to call.
176 : : */
177 [ + + ]: 623808 : if (join_path_setup_hook)
178 : 167292 : join_path_setup_hook(root, joinrel, outerrel, innerrel,
179 : : jointype, &extra);
180 : :
181 : : /*
182 : : * See if the inner relation is provably unique for this outer rel.
183 : : *
184 : : * We have some special cases: for JOIN_SEMI, it doesn't matter since the
185 : : * executor can make the equivalent optimization anyway. It also doesn't
186 : : * help enable use of Memoize, since a semijoin with a provably unique
187 : : * inner side should have been reduced to an inner join in that case.
188 : : * Therefore, we need not expend planner cycles on proofs. (For
189 : : * JOIN_ANTI, although it doesn't help the executor for the same reason,
190 : : * it can benefit Memoize paths.) For JOIN_UNIQUE_INNER, we must be
191 : : * considering a semijoin whose inner side is not provably unique (else
192 : : * reduce_unique_semijoins would've simplified it), so there's no point in
193 : : * calling innerrel_is_unique. However, if the LHS covers all of the
194 : : * semijoin's min_lefthand, then it's appropriate to set inner_unique
195 : : * because the unique relation produced by create_unique_paths will be
196 : : * unique relative to the LHS. (If we have an LHS that's only part of the
197 : : * min_lefthand, that is *not* true.) For JOIN_UNIQUE_OUTER, pass
198 : : * JOIN_INNER to avoid letting that value escape this module.
199 : : */
200 [ + + + + ]: 623808 : switch (jointype)
201 : : {
202 : 5995 : case JOIN_SEMI:
203 : 5995 : extra.inner_unique = false; /* well, unproven */
204 : 5995 : break;
205 : 4855 : case JOIN_UNIQUE_INNER:
206 : 9710 : extra.inner_unique = bms_is_subset(sjinfo->min_lefthand,
207 : 4855 : outerrel->relids);
208 : 4855 : break;
209 : 4855 : case JOIN_UNIQUE_OUTER:
210 : 4855 : extra.inner_unique = innerrel_is_unique(root,
211 : : joinrel->relids,
212 : : outerrel->relids,
213 : : innerrel,
214 : : JOIN_INNER,
215 : : restrictlist,
216 : : false);
217 : 4855 : break;
218 : 608103 : default:
219 : 608103 : extra.inner_unique = innerrel_is_unique(root,
220 : : joinrel->relids,
221 : : outerrel->relids,
222 : : innerrel,
223 : : jointype,
224 : : restrictlist,
225 : : false);
226 : 608103 : break;
227 : : }
228 : :
229 : : /*
230 : : * If the outer or inner relation has been unique-ified, handle as a plain
231 : : * inner join.
232 : : */
233 [ + + + + ]: 623808 : if (jointype == JOIN_UNIQUE_OUTER || jointype == JOIN_UNIQUE_INNER)
234 : 9710 : jointype = JOIN_INNER;
235 : :
236 : : /*
237 : : * Find potential mergejoin clauses. We can skip this if we are not
238 : : * interested in doing a mergejoin. However, mergejoin may be our only
239 : : * way of implementing a full outer join, so in that case we don't care
240 : : * whether mergejoins are disabled.
241 : : */
242 [ + + + + ]: 623808 : if ((extra.pgs_mask & PGS_MERGEJOIN_ANY) != 0 || jointype == JOIN_FULL)
243 : 543246 : extra.mergeclause_list = select_mergejoin_clauses(root,
244 : : joinrel,
245 : : outerrel,
246 : : innerrel,
247 : : restrictlist,
248 : : jointype,
249 : : &mergejoin_allowed);
250 : :
251 : : /*
252 : : * If it's SEMI, ANTI, or inner_unique join, compute correction factors
253 : : * for cost estimation. These will be the same for all paths.
254 : : */
255 [ + + + + : 623808 : if (jointype == JOIN_SEMI || jointype == JOIN_ANTI || extra.inner_unique)
+ + ]
256 : 187111 : compute_semi_anti_join_factors(root, joinrel, outerrel, innerrel,
257 : : jointype, sjinfo, restrictlist,
258 : : &extra.semifactors);
259 : :
260 : : /*
261 : : * Decide whether it's sensible to generate parameterized paths for this
262 : : * joinrel, and if so, which relations such paths should require. There
263 : : * is usually no need to create a parameterized result path unless there
264 : : * is a join order restriction that prevents joining one of our input rels
265 : : * directly to the parameter source rel instead of joining to the other
266 : : * input rel. (But see allow_star_schema_join().) This restriction
267 : : * reduces the number of parameterized paths we have to deal with at
268 : : * higher join levels, without compromising the quality of the resulting
269 : : * plan. We express the restriction as a Relids set that must overlap the
270 : : * parameterization of any proposed join path. Note: param_source_rels
271 : : * should contain only baserels, not OJ relids, so starting from
272 : : * all_baserels not all_query_rels is correct.
273 : : */
274 [ + + + + : 1145298 : foreach(lc, root->join_info_list)
+ + ]
275 : : {
276 : 521490 : SpecialJoinInfo *sjinfo2 = (SpecialJoinInfo *) lfirst(lc);
277 : :
278 : : /*
279 : : * SJ is relevant to this join if we have some part of its RHS
280 : : * (possibly not all of it), and haven't yet joined to its LHS. (This
281 : : * test is pretty simplistic, but should be sufficient considering the
282 : : * join has already been proven legal.) If the SJ is relevant, it
283 : : * presents constraints for joining to anything not in its RHS.
284 : : */
285 [ + + ]: 521490 : if (bms_overlap(joinrelids, sjinfo2->min_righthand) &&
286 [ + + ]: 331512 : !bms_overlap(joinrelids, sjinfo2->min_lefthand))
287 : 15178 : extra.param_source_rels = bms_join(extra.param_source_rels,
288 : 15178 : bms_difference(root->all_baserels,
289 : 15178 : sjinfo2->min_righthand));
290 : :
291 : : /* full joins constrain both sides symmetrically */
292 [ + + + + ]: 525448 : if (sjinfo2->jointype == JOIN_FULL &&
293 : 3958 : bms_overlap(joinrelids, sjinfo2->min_lefthand) &&
294 [ + + ]: 3922 : !bms_overlap(joinrelids, sjinfo2->min_righthand))
295 : 536 : extra.param_source_rels = bms_join(extra.param_source_rels,
296 : 536 : bms_difference(root->all_baserels,
297 : 536 : sjinfo2->min_lefthand));
298 : : }
299 : :
300 : : /*
301 : : * However, when a LATERAL subquery is involved, there will simply not be
302 : : * any paths for the joinrel that aren't parameterized by whatever the
303 : : * subquery is parameterized by, unless its parameterization is resolved
304 : : * within the joinrel. So we might as well allow additional dependencies
305 : : * on whatever residual lateral dependencies the joinrel will have.
306 : : */
307 : 1247616 : extra.param_source_rels = bms_add_members(extra.param_source_rels,
308 : 623808 : joinrel->lateral_relids);
309 : :
310 : : /*
311 : : * 1. Consider mergejoin paths where both relations must be explicitly
312 : : * sorted. Skip this if we can't mergejoin.
313 : : */
314 [ + + ]: 623808 : if (mergejoin_allowed)
315 : 613234 : sort_inner_and_outer(root, joinrel, outerrel, innerrel,
316 : : jointype, &extra);
317 : :
318 : : /*
319 : : * 2. Consider paths where the outer relation need not be explicitly
320 : : * sorted. This includes both nestloops and mergejoins where the outer
321 : : * path is already ordered. Again, skip this if we can't mergejoin.
322 : : * (That's okay because we know that nestloop can't handle
323 : : * right/right-anti/right-semi/full joins at all, so it wouldn't work in
324 : : * the prohibited cases either.)
325 : : */
326 [ + + ]: 623808 : if (mergejoin_allowed)
327 : 613234 : match_unsorted_outer(root, joinrel, outerrel, innerrel,
328 : : jointype, &extra);
329 : :
330 : : #ifdef NOT_USED
331 : :
332 : : /*
333 : : * 3. Consider paths where the inner relation need not be explicitly
334 : : * sorted. This includes mergejoins only (nestloops were already built in
335 : : * match_unsorted_outer).
336 : : *
337 : : * Diked out as redundant 2/13/2000 -- tgl. There isn't any really
338 : : * significant difference between the inner and outer side of a mergejoin,
339 : : * so match_unsorted_inner creates no paths that aren't equivalent to
340 : : * those made by match_unsorted_outer when add_paths_to_joinrel() is
341 : : * invoked with the two rels given in the other order.
342 : : */
343 : : if (mergejoin_allowed)
344 : : match_unsorted_inner(root, joinrel, outerrel, innerrel,
345 : : jointype, &extra);
346 : : #endif
347 : :
348 : : /*
349 : : * 4. Consider paths where both outer and inner relations must be hashed
350 : : * before being joined. As above, when it's a full join, we must try this
351 : : * even when the path type is disabled, because it may be our only option.
352 : : */
353 [ + + + + ]: 623808 : if ((extra.pgs_mask & PGS_HASHJOIN) != 0 || jointype == JOIN_FULL)
354 : 550542 : hash_inner_and_outer(root, joinrel, outerrel, innerrel,
355 : : jointype, &extra);
356 : :
357 : : /*
358 : : * 5. If inner and outer relations are foreign tables (or joins) belonging
359 : : * to the same server and assigned to the same user to check access
360 : : * permissions as, give the FDW a chance to push down joins.
361 : : */
362 [ + + + + ]: 623808 : if ((extra.pgs_mask & PGS_FOREIGNJOIN) != 0 && joinrel->fdwroutine &&
363 [ + + ]: 1364 : joinrel->fdwroutine->GetForeignJoinPaths)
364 : 1362 : joinrel->fdwroutine->GetForeignJoinPaths(root, joinrel,
365 : : outerrel, innerrel,
366 : : save_jointype, &extra);
367 : :
368 : : /*
369 : : * 6. Finally, give extensions a chance to manipulate the path list. They
370 : : * could add new paths (such as CustomPaths) by calling add_path(), or
371 : : * add_partial_path() if parallel aware.
372 : : *
373 : : * In theory, extensions could also use this hook to delete or modify
374 : : * paths added by the core code, but in practice this is difficult to make
375 : : * work, since it's too late to get back any paths that have already been
376 : : * discarded by add_path() or add_partial_path(). If you're trying to
377 : : * suppress paths, consider using join_path_setup_hook instead.
378 : : */
379 [ - + ]: 623808 : if (set_join_pathlist_hook)
380 : 0 : set_join_pathlist_hook(root, joinrel, outerrel, innerrel,
381 : : save_jointype, &extra);
382 : 623808 : }
383 : :
384 : : /*
385 : : * We override the param_source_rels heuristic to accept nestloop paths in
386 : : * which the outer rel satisfies some but not all of the inner path's
387 : : * parameterization. This is necessary to get good plans for star-schema
388 : : * scenarios, in which a parameterized path for a large table may require
389 : : * parameters from multiple small tables that will not get joined directly to
390 : : * each other. We can handle that by stacking nestloops that have the small
391 : : * tables on the outside; but this breaks the rule the param_source_rels
392 : : * heuristic is based on, namely that parameters should not be passed down
393 : : * across joins unless there's a join-order-constraint-based reason to do so.
394 : : * So we ignore the param_source_rels restriction when this case applies.
395 : : *
396 : : * allow_star_schema_join() returns true if the param_source_rels restriction
397 : : * should be overridden, ie, it's okay to perform this join.
398 : : */
399 : : static inline bool
400 : 228322 : allow_star_schema_join(PlannerInfo *root,
401 : : Relids outerrelids,
402 : : Relids inner_paramrels)
403 : : {
404 : : /*
405 : : * It's a star-schema case if the outer rel provides some but not all of
406 : : * the inner rel's parameterization.
407 : : */
408 [ + + + + ]: 267271 : return (bms_overlap(inner_paramrels, outerrelids) &&
409 : 38949 : bms_nonempty_difference(inner_paramrels, outerrelids));
410 : : }
411 : :
412 : : /*
413 : : * If the parameterization is only partly satisfied by the outer rel,
414 : : * the unsatisfied part can't include any outer-join relids that could
415 : : * null rels of the satisfied part. That would imply that we're trying
416 : : * to use a clause involving a Var with nonempty varnullingrels at
417 : : * a join level where that value isn't yet computable.
418 : : *
419 : : * In practice, this test never finds a problem because earlier join order
420 : : * restrictions prevent us from attempting a join that would cause a problem.
421 : : * (That's unsurprising, because the code worked before we ever added
422 : : * outer-join relids to expression relids.) It still seems worth checking
423 : : * as a backstop, but we only do so in assert-enabled builds.
424 : : */
425 : : #ifdef USE_ASSERT_CHECKING
426 : : static inline bool
427 : : have_unsafe_outer_join_ref(PlannerInfo *root,
428 : : Relids outerrelids,
429 : : Relids inner_paramrels)
430 : : {
431 : : bool result = false;
432 : : Relids unsatisfied = bms_difference(inner_paramrels, outerrelids);
433 : : Relids satisfied = bms_intersect(inner_paramrels, outerrelids);
434 : :
435 : : if (bms_overlap(unsatisfied, root->outer_join_rels))
436 : : {
437 : : ListCell *lc;
438 : :
439 : : foreach(lc, root->join_info_list)
440 : : {
441 : : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(lc);
442 : :
443 : : if (!bms_is_member(sjinfo->ojrelid, unsatisfied))
444 : : continue; /* not relevant */
445 : : if (bms_overlap(satisfied, sjinfo->min_righthand) ||
446 : : (sjinfo->jointype == JOIN_FULL &&
447 : : bms_overlap(satisfied, sjinfo->min_lefthand)))
448 : : {
449 : : result = true; /* doesn't work */
450 : : break;
451 : : }
452 : : }
453 : : }
454 : :
455 : : /* Waste no memory when we reject a path here */
456 : : bms_free(unsatisfied);
457 : : bms_free(satisfied);
458 : :
459 : : return result;
460 : : }
461 : : #endif /* USE_ASSERT_CHECKING */
462 : :
463 : : /*
464 : : * paraminfo_get_equal_hashops
465 : : * Determine if the clauses in param_info and innerrel's lateral vars
466 : : * can be hashed.
467 : : * Returns true if hashing is possible, otherwise false.
468 : : *
469 : : * Additionally, on success we collect the outer expressions and the
470 : : * appropriate equality operators for each hashable parameter to innerrel.
471 : : * These are returned in parallel lists in *param_exprs and *operators.
472 : : * We also set *binary_mode to indicate whether strict binary matching is
473 : : * required.
474 : : */
475 : : static bool
476 : 259080 : paraminfo_get_equal_hashops(PlannerInfo *root, ParamPathInfo *param_info,
477 : : RelOptInfo *outerrel, RelOptInfo *innerrel,
478 : : List *ph_lateral_vars, List **param_exprs,
479 : : List **operators, bool *binary_mode)
480 : :
481 : : {
482 : : List *lateral_vars;
483 : : ListCell *lc;
484 : :
485 : 259080 : *param_exprs = NIL;
486 : 259080 : *operators = NIL;
487 : 259080 : *binary_mode = false;
488 : :
489 : : /* Add join clauses from param_info to the hash key */
490 [ + - ]: 259080 : if (param_info != NULL)
491 : : {
492 : 259080 : List *clauses = param_info->ppi_clauses;
493 : :
494 [ + + + + : 486055 : foreach(lc, clauses)
+ + ]
495 : : {
496 : 277593 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
497 : : OpExpr *opexpr;
498 : : Node *expr;
499 : : Oid hasheqoperator;
500 : :
501 : 277593 : opexpr = (OpExpr *) rinfo->clause;
502 : :
503 : : /*
504 : : * Bail if the rinfo is not compatible. We need a join OpExpr
505 : : * with 2 args.
506 : : */
507 [ + + + - ]: 277593 : if (!IsA(opexpr, OpExpr) || list_length(opexpr->args) != 2 ||
508 [ + + ]: 267716 : !clause_sides_match_join(rinfo, outerrel->relids,
509 : : innerrel->relids))
510 : : {
511 : 50558 : list_free(*operators);
512 : 50558 : list_free(*param_exprs);
513 : 50618 : return false;
514 : : }
515 : :
516 [ + + ]: 227035 : if (rinfo->outer_is_left)
517 : : {
518 : 128989 : expr = (Node *) linitial(opexpr->args);
519 : 128989 : hasheqoperator = rinfo->left_hasheqoperator;
520 : : }
521 : : else
522 : : {
523 : 98046 : expr = (Node *) lsecond(opexpr->args);
524 : 98046 : hasheqoperator = rinfo->right_hasheqoperator;
525 : : }
526 : :
527 : : /* can't do memoize if we can't hash the outer type */
528 [ + + ]: 227035 : if (!OidIsValid(hasheqoperator))
529 : : {
530 : 60 : list_free(*operators);
531 : 60 : list_free(*param_exprs);
532 : 60 : return false;
533 : : }
534 : :
535 : : /*
536 : : * 'expr' may already exist as a parameter from a previous item in
537 : : * ppi_clauses. No need to include it again, however we'd better
538 : : * ensure we do switch into binary mode if required. See below.
539 : : */
540 [ + + ]: 226975 : if (!list_member(*param_exprs, expr))
541 : : {
542 : 226971 : *operators = lappend_oid(*operators, hasheqoperator);
543 : 226971 : *param_exprs = lappend(*param_exprs, expr);
544 : : }
545 : :
546 : : /*
547 : : * When the join operator is not hashable then it's possible that
548 : : * the operator will be able to distinguish something that the
549 : : * hash equality operator could not. For example with floating
550 : : * point types -0.0 and +0.0 are classed as equal by the hash
551 : : * function and equality function, but some other operator may be
552 : : * able to tell those values apart. This means that we must put
553 : : * memoize into binary comparison mode so that it does bit-by-bit
554 : : * comparisons rather than a "logical" comparison as it would
555 : : * using the hash equality operator.
556 : : */
557 [ + + ]: 226975 : if (!OidIsValid(rinfo->hashjoinoperator))
558 : 747 : *binary_mode = true;
559 : : }
560 : : }
561 : :
562 : : /* Now add any lateral vars to the cache key too */
563 : 208462 : lateral_vars = list_concat(ph_lateral_vars, innerrel->lateral_vars);
564 [ + + + + : 214143 : foreach(lc, lateral_vars)
+ + ]
565 : : {
566 : 6493 : Node *expr = (Node *) lfirst(lc);
567 : : TypeCacheEntry *typentry;
568 : :
569 : : /* Reject if there are any volatile functions in lateral vars */
570 [ - + ]: 6493 : if (contain_volatile_functions(expr))
571 : : {
572 : 0 : list_free(*operators);
573 : 0 : list_free(*param_exprs);
574 : 812 : return false;
575 : : }
576 : :
577 : 6493 : typentry = lookup_type_cache(exprType(expr),
578 : : TYPECACHE_HASH_PROC | TYPECACHE_EQ_OPR);
579 : :
580 : : /* can't use memoize without a valid hash proc and equals operator */
581 [ + + - + ]: 6493 : if (!OidIsValid(typentry->hash_proc) || !OidIsValid(typentry->eq_opr))
582 : : {
583 : 812 : list_free(*operators);
584 : 812 : list_free(*param_exprs);
585 : 812 : return false;
586 : : }
587 : :
588 : : /*
589 : : * 'expr' may already exist as a parameter from the ppi_clauses. No
590 : : * need to include it again, however we'd better ensure we do switch
591 : : * into binary mode.
592 : : */
593 [ + + ]: 5681 : if (!list_member(*param_exprs, expr))
594 : : {
595 : 5337 : *operators = lappend_oid(*operators, typentry->eq_opr);
596 : 5337 : *param_exprs = lappend(*param_exprs, expr);
597 : : }
598 : :
599 : : /*
600 : : * We must go into binary mode as we don't have too much of an idea of
601 : : * how these lateral Vars are being used. See comment above when we
602 : : * set *binary_mode for the non-lateral Var case. This could be
603 : : * relaxed a bit if we had the RestrictInfos and knew the operators
604 : : * being used, however for cases like Vars that are arguments to
605 : : * functions we must operate in binary mode as we don't have
606 : : * visibility into what the function is doing with the Vars.
607 : : */
608 : 5681 : *binary_mode = true;
609 : : }
610 : :
611 : : /* We're okay to use memoize */
612 : 207650 : return true;
613 : : }
614 : :
615 : : /*
616 : : * extract_lateral_vars_from_PHVs
617 : : * Extract lateral references within PlaceHolderVars that are due to be
618 : : * evaluated at 'innerrelids'.
619 : : */
620 : : static List *
621 : 1013544 : extract_lateral_vars_from_PHVs(PlannerInfo *root, Relids innerrelids)
622 : : {
623 : 1013544 : List *ph_lateral_vars = NIL;
624 : : ListCell *lc;
625 : :
626 : : /* Nothing would be found if the query contains no LATERAL RTEs */
627 [ + + ]: 1013544 : if (!root->hasLateralRTEs)
628 : 966555 : return NIL;
629 : :
630 : : /*
631 : : * No need to consider PHVs that are due to be evaluated at joinrels,
632 : : * since we do not add Memoize nodes on top of joinrel paths.
633 : : */
634 [ + + ]: 46989 : if (bms_membership(innerrelids) == BMS_MULTIPLE)
635 : 19343 : return NIL;
636 : :
637 [ + + + + : 29568 : foreach(lc, root->placeholder_list)
+ + ]
638 : : {
639 : 1922 : PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(lc);
640 : : List *vars;
641 : : ListCell *cell;
642 : :
643 : : /* PHV is uninteresting if no lateral refs */
644 [ + + ]: 1922 : if (phinfo->ph_lateral == NULL)
645 : 1102 : continue;
646 : :
647 : : /* PHV is uninteresting if not due to be evaluated at innerrelids */
648 [ + + ]: 820 : if (!bms_equal(phinfo->ph_eval_at, innerrelids))
649 : 654 : continue;
650 : :
651 : : /*
652 : : * If the PHV does not reference any rels in innerrelids, use its
653 : : * contained expression as a cache key rather than extracting the
654 : : * Vars/PHVs from it and using those. This can be beneficial in cases
655 : : * where the expression results in fewer distinct values to cache
656 : : * tuples for.
657 : : */
658 [ + + ]: 166 : if (!bms_overlap(pull_varnos(root, (Node *) phinfo->ph_var->phexpr),
659 : : innerrelids))
660 : : {
661 : 158 : ph_lateral_vars = lappend(ph_lateral_vars, phinfo->ph_var->phexpr);
662 : 158 : continue;
663 : : }
664 : :
665 : : /* Fetch Vars and PHVs of lateral references within PlaceHolderVars */
666 : 8 : vars = pull_vars_of_level((Node *) phinfo->ph_var->phexpr, 0);
667 [ + - + + : 24 : foreach(cell, vars)
+ + ]
668 : : {
669 : 16 : Node *node = (Node *) lfirst(cell);
670 : :
671 [ + + ]: 16 : if (IsA(node, Var))
672 : : {
673 : 8 : Var *var = (Var *) node;
674 : :
675 : : Assert(var->varlevelsup == 0);
676 : :
677 [ - + ]: 8 : if (bms_is_member(var->varno, phinfo->ph_lateral))
678 : 0 : ph_lateral_vars = lappend(ph_lateral_vars, node);
679 : : }
680 [ + - ]: 8 : else if (IsA(node, PlaceHolderVar))
681 : : {
682 : 8 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
683 : :
684 : : Assert(phv->phlevelsup == 0);
685 : :
686 [ + - ]: 8 : if (bms_is_subset(find_placeholder_info(root, phv)->ph_eval_at,
687 : 8 : phinfo->ph_lateral))
688 : 8 : ph_lateral_vars = lappend(ph_lateral_vars, node);
689 : : }
690 : : else
691 : : Assert(false);
692 : : }
693 : :
694 : 8 : list_free(vars);
695 : : }
696 : :
697 : 27646 : return ph_lateral_vars;
698 : : }
699 : :
700 : : /*
701 : : * get_memoize_path
702 : : * If possible, make and return a Memoize path atop of 'inner_path'.
703 : : * Otherwise return NULL.
704 : : *
705 : : * Note that currently we do not add Memoize nodes on top of join relation
706 : : * paths. This is because the ParamPathInfos for join relation paths do not
707 : : * maintain ppi_clauses, as the set of relevant clauses varies depending on how
708 : : * the join is formed. In addition, joinrels do not maintain lateral_vars. So
709 : : * we do not have a way to extract cache keys from joinrels.
710 : : */
711 : : static Path *
712 : 1652996 : get_memoize_path(PlannerInfo *root, RelOptInfo *innerrel,
713 : : RelOptInfo *outerrel, Path *inner_path,
714 : : Path *outer_path, JoinType jointype,
715 : : JoinPathExtraData *extra)
716 : : {
717 : : List *param_exprs;
718 : : List *hash_operators;
719 : : ListCell *lc;
720 : : bool binary_mode;
721 : : List *ph_lateral_vars;
722 : :
723 : : /* Obviously not if it's disabled */
724 [ + + ]: 1652996 : if ((extra->pgs_mask & PGS_NESTLOOP_MEMOIZE) == 0)
725 : 181424 : return NULL;
726 : :
727 : : /*
728 : : * We can safely not bother with all this unless we expect to perform more
729 : : * than one inner scan. The first scan is always going to be a cache
730 : : * miss. This would likely fail later anyway based on costs, so this is
731 : : * really just to save some wasted effort.
732 : : *
733 : : * However, if the "plain nested loop" strategy is disabled, then it is no
734 : : * longer certain that any path we'd construct here would lose on cost.
735 : : * So, in that case, continue and let cost comparison sort things out.
736 : : */
737 [ + + ]: 1471572 : if (outer_path->parent->rows < 2 &&
738 [ + - ]: 458028 : (extra->pgs_mask & PGS_NESTLOOP_PLAIN) != 0)
739 : 458028 : return NULL;
740 : :
741 : : /*
742 : : * Extract lateral Vars/PHVs within PlaceHolderVars that are due to be
743 : : * evaluated at innerrel. These lateral Vars/PHVs could be used as
744 : : * memoize cache keys.
745 : : */
746 : 1013544 : ph_lateral_vars = extract_lateral_vars_from_PHVs(root, innerrel->relids);
747 : :
748 : : /*
749 : : * We can only have a memoize node when there's some kind of cache key,
750 : : * either parameterized path clauses or lateral Vars. No cache key sounds
751 : : * more like something a Materialize node might be more useful for.
752 : : */
753 [ + + ]: 1013544 : if ((inner_path->param_info == NULL ||
754 [ + + ]: 360041 : inner_path->param_info->ppi_clauses == NIL) &&
755 [ + + + + ]: 678906 : innerrel->lateral_vars == NIL &&
756 : : ph_lateral_vars == NIL)
757 : 674016 : return NULL;
758 : :
759 : : /*
760 : : * Currently we don't do this for SEMI and ANTI joins, because nested loop
761 : : * SEMI/ANTI joins don't scan the inner node to completion, which means
762 : : * memoize cannot mark the cache entry as complete. Nor can we mark the
763 : : * cache entry as complete after fetching the first inner tuple, because
764 : : * if that tuple and the current outer tuple don't satisfy the join
765 : : * clauses, a second inner tuple that satisfies the parameters would find
766 : : * the cache entry already marked as complete. The only exception is when
767 : : * the inner relation is provably unique, as in that case, there won't be
768 : : * a second matching tuple and we can safely mark the cache entry as
769 : : * complete after fetching the first inner tuple. Note that in such
770 : : * cases, the SEMI join should have been reduced to an inner join by
771 : : * reduce_unique_semijoins.
772 : : */
773 [ + + + + ]: 339528 : if ((jointype == JOIN_SEMI || jointype == JOIN_ANTI) &&
774 [ + + ]: 18757 : !extra->inner_unique)
775 : 4479 : return NULL;
776 : :
777 : : /*
778 : : * Memoize normally marks cache entries as complete when it runs out of
779 : : * tuples to read from its subplan. However, with unique joins, Nested
780 : : * Loop will skip to the next outer tuple after finding the first matching
781 : : * inner tuple. This means that we may not read the inner side of the
782 : : * join to completion which leaves no opportunity to mark the cache entry
783 : : * as complete. To work around that, when the join is unique we
784 : : * automatically mark cache entries as complete after fetching the first
785 : : * tuple. This works when the entire join condition is parameterized.
786 : : * Otherwise, when the parameterization is only a subset of the join
787 : : * condition, we can't be sure which part of it causes the join to be
788 : : * unique. This means there are no guarantees that only 1 tuple will be
789 : : * read. We cannot mark the cache entry as complete after reading the
790 : : * first tuple without that guarantee. This means the scope of Memoize
791 : : * node's usefulness is limited to only outer rows that have no join
792 : : * partner as this is the only case where Nested Loop would exhaust the
793 : : * inner scan of a unique join. Since the scope is limited to that, we
794 : : * just don't bother making a memoize path in this case.
795 : : *
796 : : * Lateral vars needn't be considered here as they're not considered when
797 : : * determining if the join is unique.
798 : : */
799 [ + + ]: 335049 : if (extra->inner_unique)
800 : : {
801 : : Bitmapset *ppi_serials;
802 : :
803 [ - + ]: 207352 : if (inner_path->param_info == NULL)
804 : 0 : return NULL;
805 : :
806 : 207352 : ppi_serials = inner_path->param_info->ppi_serials;
807 : :
808 [ + - + + : 496396 : foreach_node(RestrictInfo, rinfo, extra->restrictlist)
+ + ]
809 : : {
810 [ + + ]: 233420 : if (!bms_is_member(rinfo->rinfo_serial, ppi_serials))
811 : 75864 : return NULL;
812 : : }
813 : : }
814 : :
815 : : /*
816 : : * We can't use a memoize node if there are volatile functions in the
817 : : * inner rel's target list or restrict list. A cache hit could reduce the
818 : : * number of calls to these functions.
819 : : */
820 [ - + ]: 259185 : if (contain_volatile_functions((Node *) innerrel->reltarget))
821 : 0 : return NULL;
822 : :
823 [ + + + + : 440176 : foreach(lc, innerrel->baserestrictinfo)
+ + ]
824 : : {
825 : 181095 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
826 : :
827 [ + + ]: 181095 : if (contain_volatile_functions((Node *) rinfo))
828 : 104 : return NULL;
829 : : }
830 : :
831 : : /*
832 : : * Also check the parameterized path restrictinfos for volatile functions.
833 : : * Indexed functions must be immutable so shouldn't have any volatile
834 : : * functions, however, with a lateral join the inner scan may not be an
835 : : * index scan.
836 : : */
837 [ + - ]: 259081 : if (inner_path->param_info != NULL)
838 : : {
839 [ + + + + : 554696 : foreach(lc, inner_path->param_info->ppi_clauses)
+ + ]
840 : : {
841 : 295616 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
842 : :
843 [ + + ]: 295616 : if (contain_volatile_functions((Node *) rinfo))
844 : 1 : return NULL;
845 : : }
846 : : }
847 : :
848 : : /* Check if we have hash ops for each parameter to the path */
849 [ + + ]: 259080 : if (paraminfo_get_equal_hashops(root,
850 : : inner_path->param_info,
851 [ + + ]: 259080 : outerrel->top_parent ?
852 : : outerrel->top_parent : outerrel,
853 : : innerrel,
854 : : ph_lateral_vars,
855 : : ¶m_exprs,
856 : : &hash_operators,
857 : : &binary_mode))
858 : : {
859 : 207650 : return (Path *) create_memoize_path(root,
860 : : innerrel,
861 : : inner_path,
862 : : param_exprs,
863 : : hash_operators,
864 : 207650 : extra->inner_unique,
865 : : binary_mode,
866 : : outer_path->rows);
867 : : }
868 : :
869 : 51430 : return NULL;
870 : : }
871 : :
872 : : /*
873 : : * try_nestloop_path
874 : : * Consider a nestloop join path; if it appears useful, push it into
875 : : * the joinrel's pathlist via add_path().
876 : : */
877 : : static void
878 : 2625056 : try_nestloop_path(PlannerInfo *root,
879 : : RelOptInfo *joinrel,
880 : : Path *outer_path,
881 : : Path *inner_path,
882 : : List *pathkeys,
883 : : JoinType jointype,
884 : : uint64 nestloop_subtype,
885 : : JoinPathExtraData *extra)
886 : : {
887 : : Relids required_outer;
888 : : JoinCostWorkspace workspace;
889 : 2625056 : RelOptInfo *innerrel = inner_path->parent;
890 : 2625056 : RelOptInfo *outerrel = outer_path->parent;
891 : : Relids innerrelids;
892 : : Relids outerrelids;
893 [ + + ]: 2625056 : Relids inner_paramrels = PATH_REQ_OUTER(inner_path);
894 [ + + ]: 2625056 : Relids outer_paramrels = PATH_REQ_OUTER(outer_path);
895 : :
896 : : /*
897 : : * If we are forming an outer join at this join, it's nonsensical to use
898 : : * an input path that uses the outer join as part of its parameterization.
899 : : * (This can happen despite our join order restrictions, since those apply
900 : : * to what is in an input relation not what its parameters are.)
901 : : */
902 [ + + + - ]: 3022830 : if (extra->sjinfo->ojrelid != 0 &&
903 [ + + ]: 795548 : (bms_is_member(extra->sjinfo->ojrelid, inner_paramrels) ||
904 : 397774 : bms_is_member(extra->sjinfo->ojrelid, outer_paramrels)))
905 : 224902 : return;
906 : :
907 : : /*
908 : : * Any parameterization of the input paths refers to topmost parents of
909 : : * the relevant relations, because reparameterize_path_by_child() hasn't
910 : : * been called yet. So we must consider topmost parents of the relations
911 : : * being joined, too, while determining parameterization of the result and
912 : : * checking for disallowed parameterization cases.
913 : : */
914 [ + + ]: 2624956 : if (innerrel->top_parent_relids)
915 : 134037 : innerrelids = innerrel->top_parent_relids;
916 : : else
917 : 2490919 : innerrelids = innerrel->relids;
918 : :
919 [ + + ]: 2624956 : if (outerrel->top_parent_relids)
920 : 134037 : outerrelids = outerrel->top_parent_relids;
921 : : else
922 : 2490919 : outerrelids = outerrel->relids;
923 : :
924 : : /*
925 : : * Check to see if proposed path is still parameterized, and reject if the
926 : : * parameterization wouldn't be sensible --- unless allow_star_schema_join
927 : : * says to allow it anyway.
928 : : */
929 : 2624956 : required_outer = calc_nestloop_required_outer(outerrelids, outer_paramrels,
930 : : innerrelids, inner_paramrels);
931 [ + + ]: 2624956 : if (required_outer &&
932 [ + + ]: 267183 : !bms_overlap(required_outer, extra->param_source_rels) &&
933 [ + + ]: 228322 : !allow_star_schema_join(root, outerrelids, inner_paramrels))
934 : : {
935 : : /* Waste no memory when we reject a path here */
936 : 224802 : bms_free(required_outer);
937 : 224802 : return;
938 : : }
939 : :
940 : : /* If we got past that, we shouldn't have any unsafe outer-join refs */
941 : : Assert(!have_unsafe_outer_join_ref(root, outerrelids, inner_paramrels));
942 : :
943 : : /*
944 : : * If the inner path is parameterized, it is parameterized by the topmost
945 : : * parent of the outer rel, not the outer rel itself. We will need to
946 : : * translate the parameterization, if this path is chosen, during
947 : : * create_plan(). Here we just check whether we will be able to perform
948 : : * the translation, and if not avoid creating a nestloop path.
949 : : */
950 [ + + + - : 2400154 : if (PATH_PARAM_BY_PARENT(inner_path, outer_path->parent) &&
+ + ]
951 [ - + ]: 10645 : !path_is_reparameterizable_by_child(inner_path, outer_path->parent))
952 : : {
953 : 0 : bms_free(required_outer);
954 : 0 : return;
955 : : }
956 : :
957 : : /*
958 : : * Do a precheck to quickly eliminate obviously-inferior paths. We
959 : : * calculate a cheap lower bound on the path's cost and then use
960 : : * add_path_precheck() to see if the path is clearly going to be dominated
961 : : * by some existing path for the joinrel. If not, do the full pushup with
962 : : * creating a fully valid path structure and submitting it to add_path().
963 : : * The latter two steps are expensive enough to make this two-phase
964 : : * methodology worthwhile.
965 : : */
966 : 2400154 : initial_cost_nestloop(root, &workspace, jointype,
967 : : nestloop_subtype | PGS_CONSIDER_NONPARTIAL,
968 : : outer_path, inner_path, extra);
969 : :
970 [ + + ]: 2400154 : if (add_path_precheck(joinrel, workspace.disabled_nodes,
971 : : workspace.startup_cost, workspace.total_cost,
972 : : pathkeys, required_outer))
973 : : {
974 : 1126102 : add_path(joinrel, (Path *)
975 : 1126102 : create_nestloop_path(root,
976 : : joinrel,
977 : : jointype,
978 : : &workspace,
979 : : extra,
980 : : outer_path,
981 : : inner_path,
982 : : extra->restrictlist,
983 : : pathkeys,
984 : : required_outer));
985 : : }
986 : : else
987 : : {
988 : : /* Waste no memory when we reject a path here */
989 : 1274052 : bms_free(required_outer);
990 : : }
991 : : }
992 : :
993 : : /*
994 : : * try_partial_nestloop_path
995 : : * Consider a partial nestloop join path; if it appears useful, push it into
996 : : * the joinrel's partial_pathlist via add_partial_path().
997 : : */
998 : : static void
999 : 157975 : try_partial_nestloop_path(PlannerInfo *root,
1000 : : RelOptInfo *joinrel,
1001 : : Path *outer_path,
1002 : : Path *inner_path,
1003 : : List *pathkeys,
1004 : : JoinType jointype,
1005 : : uint64 nestloop_subtype,
1006 : : JoinPathExtraData *extra)
1007 : : {
1008 : : JoinCostWorkspace workspace;
1009 : :
1010 : : /*
1011 : : * If the inner path is parameterized, the parameterization must be fully
1012 : : * satisfied by the proposed outer path. Parameterized partial paths are
1013 : : * not supported. The caller should already have verified that no lateral
1014 : : * rels are required here.
1015 : : */
1016 : : Assert(bms_is_empty(joinrel->lateral_relids));
1017 : : Assert(bms_is_empty(PATH_REQ_OUTER(outer_path)));
1018 [ + + ]: 157975 : if (inner_path->param_info != NULL)
1019 : : {
1020 : 12372 : Relids inner_paramrels = inner_path->param_info->ppi_req_outer;
1021 : 12372 : RelOptInfo *outerrel = outer_path->parent;
1022 : : Relids outerrelids;
1023 : :
1024 : : /*
1025 : : * The inner and outer paths are parameterized, if at all, by the top
1026 : : * level parents, not the child relations, so we must use those relids
1027 : : * for our parameterization tests.
1028 : : */
1029 [ + + ]: 12372 : if (outerrel->top_parent_relids)
1030 : 8708 : outerrelids = outerrel->top_parent_relids;
1031 : : else
1032 : 3664 : outerrelids = outerrel->relids;
1033 : :
1034 [ + + ]: 12372 : if (!bms_is_subset(inner_paramrels, outerrelids))
1035 : 119659 : return;
1036 : : }
1037 : :
1038 : : /*
1039 : : * If the inner path is parameterized, it is parameterized by the topmost
1040 : : * parent of the outer rel, not the outer rel itself. We will need to
1041 : : * translate the parameterization, if this path is chosen, during
1042 : : * create_plan(). Here we just check whether we will be able to perform
1043 : : * the translation, and if not avoid creating a nestloop path.
1044 : : */
1045 [ + + + - : 156796 : if (PATH_PARAM_BY_PARENT(inner_path, outer_path->parent) &&
+ + ]
1046 [ - + ]: 7920 : !path_is_reparameterizable_by_child(inner_path, outer_path->parent))
1047 : 0 : return;
1048 : :
1049 : : /*
1050 : : * Before creating a path, get a quick lower bound on what it is likely to
1051 : : * cost. Bail out right away if it looks terrible.
1052 : : */
1053 : 156796 : initial_cost_nestloop(root, &workspace, jointype, nestloop_subtype,
1054 : : outer_path, inner_path, extra);
1055 [ + + ]: 156796 : if (!add_partial_path_precheck(joinrel, workspace.disabled_nodes,
1056 : : workspace.startup_cost,
1057 : : workspace.total_cost, pathkeys))
1058 : 118480 : return;
1059 : :
1060 : : /* Might be good enough to be worth trying, so let's try it. */
1061 : 38316 : add_partial_path(joinrel, (Path *)
1062 : 38316 : create_nestloop_path(root,
1063 : : joinrel,
1064 : : jointype,
1065 : : &workspace,
1066 : : extra,
1067 : : outer_path,
1068 : : inner_path,
1069 : : extra->restrictlist,
1070 : : pathkeys,
1071 : : NULL));
1072 : : }
1073 : :
1074 : : /*
1075 : : * try_mergejoin_path
1076 : : * Consider a merge join path; if it appears useful, push it into
1077 : : * the joinrel's pathlist via add_path().
1078 : : */
1079 : : static void
1080 : 1062419 : try_mergejoin_path(PlannerInfo *root,
1081 : : RelOptInfo *joinrel,
1082 : : Path *outer_path,
1083 : : Path *inner_path,
1084 : : List *pathkeys,
1085 : : List *mergeclauses,
1086 : : List *outersortkeys,
1087 : : List *innersortkeys,
1088 : : JoinType jointype,
1089 : : JoinPathExtraData *extra,
1090 : : bool is_partial)
1091 : : {
1092 : : Relids required_outer;
1093 : 1062419 : int outer_presorted_keys = 0;
1094 : : JoinCostWorkspace workspace;
1095 : :
1096 [ + + ]: 1062419 : if (is_partial)
1097 : : {
1098 : 16442 : try_partial_mergejoin_path(root,
1099 : : joinrel,
1100 : : outer_path,
1101 : : inner_path,
1102 : : pathkeys,
1103 : : mergeclauses,
1104 : : outersortkeys,
1105 : : innersortkeys,
1106 : : jointype,
1107 : : extra);
1108 : 42286 : return;
1109 : : }
1110 : :
1111 : : /*
1112 : : * If we are forming an outer join at this join, it's nonsensical to use
1113 : : * an input path that uses the outer join as part of its parameterization.
1114 : : * (This can happen despite our join order restrictions, since those apply
1115 : : * to what is in an input relation not what its parameters are.)
1116 : : */
1117 [ + + + - ]: 1266468 : if (extra->sjinfo->ojrelid != 0 &&
1118 [ + + + + ]: 440982 : (bms_is_member(extra->sjinfo->ojrelid, PATH_REQ_OUTER(inner_path)) ||
1119 [ + + ]: 220491 : bms_is_member(extra->sjinfo->ojrelid, PATH_REQ_OUTER(outer_path))))
1120 : 10 : return;
1121 : :
1122 : : /*
1123 : : * Check to see if proposed path is still parameterized, and reject if the
1124 : : * parameterization wouldn't be sensible.
1125 : : */
1126 : 1045967 : required_outer = calc_non_nestloop_required_outer(outer_path,
1127 : : inner_path);
1128 [ + + ]: 1045967 : if (required_outer &&
1129 [ + + ]: 31610 : !bms_overlap(required_outer, extra->param_source_rels))
1130 : : {
1131 : : /* Waste no memory when we reject a path here */
1132 : 25834 : bms_free(required_outer);
1133 : 25834 : return;
1134 : : }
1135 : :
1136 : : /*
1137 : : * If the given paths are already well enough ordered, we can skip doing
1138 : : * an explicit sort.
1139 : : *
1140 : : * We need to determine the number of presorted keys of the outer path to
1141 : : * decide whether explicit incremental sort can be applied when
1142 : : * outersortkeys is not NIL. We do not need to do the same for the inner
1143 : : * path though, as incremental sort currently does not support
1144 : : * mark/restore.
1145 : : */
1146 [ + + + + ]: 1540006 : if (outersortkeys &&
1147 : 519873 : pathkeys_count_contained_in(outersortkeys, outer_path->pathkeys,
1148 : : &outer_presorted_keys))
1149 : 12817 : outersortkeys = NIL;
1150 [ + + + + ]: 1853685 : if (innersortkeys &&
1151 : 833552 : pathkeys_contained_in(innersortkeys, inner_path->pathkeys))
1152 : 21600 : innersortkeys = NIL;
1153 : :
1154 : : /*
1155 : : * See comments in try_nestloop_path().
1156 : : */
1157 : 1020133 : initial_cost_mergejoin(root, &workspace, jointype, mergeclauses,
1158 : : outer_path, inner_path,
1159 : : outersortkeys, innersortkeys,
1160 : : outer_presorted_keys,
1161 : : extra);
1162 : :
1163 [ + + ]: 1020133 : if (add_path_precheck(joinrel, workspace.disabled_nodes,
1164 : : workspace.startup_cost, workspace.total_cost,
1165 : : pathkeys, required_outer))
1166 : : {
1167 : 303587 : add_path(joinrel, (Path *)
1168 : 303587 : create_mergejoin_path(root,
1169 : : joinrel,
1170 : : jointype,
1171 : : &workspace,
1172 : : extra,
1173 : : outer_path,
1174 : : inner_path,
1175 : : extra->restrictlist,
1176 : : pathkeys,
1177 : : required_outer,
1178 : : mergeclauses,
1179 : : outersortkeys,
1180 : : innersortkeys,
1181 : : outer_presorted_keys));
1182 : : }
1183 : : else
1184 : : {
1185 : : /* Waste no memory when we reject a path here */
1186 : 716546 : bms_free(required_outer);
1187 : : }
1188 : : }
1189 : :
1190 : : /*
1191 : : * try_partial_mergejoin_path
1192 : : * Consider a partial merge join path; if it appears useful, push it into
1193 : : * the joinrel's pathlist via add_partial_path().
1194 : : */
1195 : : static void
1196 : 71754 : try_partial_mergejoin_path(PlannerInfo *root,
1197 : : RelOptInfo *joinrel,
1198 : : Path *outer_path,
1199 : : Path *inner_path,
1200 : : List *pathkeys,
1201 : : List *mergeclauses,
1202 : : List *outersortkeys,
1203 : : List *innersortkeys,
1204 : : JoinType jointype,
1205 : : JoinPathExtraData *extra)
1206 : : {
1207 : 71754 : int outer_presorted_keys = 0;
1208 : : JoinCostWorkspace workspace;
1209 : :
1210 : : /*
1211 : : * See comments in try_partial_hashjoin_path().
1212 : : */
1213 : : Assert(bms_is_empty(joinrel->lateral_relids));
1214 : : Assert(bms_is_empty(PATH_REQ_OUTER(outer_path)));
1215 [ - + - - ]: 71754 : if (!bms_is_empty(PATH_REQ_OUTER(inner_path)))
1216 : 24473 : return;
1217 : :
1218 : : /*
1219 : : * If the given paths are already well enough ordered, we can skip doing
1220 : : * an explicit sort.
1221 : : *
1222 : : * We need to determine the number of presorted keys of the outer path to
1223 : : * decide whether explicit incremental sort can be applied when
1224 : : * outersortkeys is not NIL. We do not need to do the same for the inner
1225 : : * path though, as incremental sort currently does not support
1226 : : * mark/restore.
1227 : : */
1228 [ + + + + ]: 127066 : if (outersortkeys &&
1229 : 55312 : pathkeys_count_contained_in(outersortkeys, outer_path->pathkeys,
1230 : : &outer_presorted_keys))
1231 : 138 : outersortkeys = NIL;
1232 [ + + + + ]: 141366 : if (innersortkeys &&
1233 : 69612 : pathkeys_contained_in(innersortkeys, inner_path->pathkeys))
1234 : 458 : innersortkeys = NIL;
1235 : :
1236 : : /*
1237 : : * See comments in try_partial_nestloop_path().
1238 : : */
1239 : 71754 : initial_cost_mergejoin(root, &workspace, jointype, mergeclauses,
1240 : : outer_path, inner_path,
1241 : : outersortkeys, innersortkeys,
1242 : : outer_presorted_keys,
1243 : : extra);
1244 : :
1245 [ + + ]: 71754 : if (!add_partial_path_precheck(joinrel, workspace.disabled_nodes,
1246 : : workspace.startup_cost,
1247 : : workspace.total_cost, pathkeys))
1248 : 24473 : return;
1249 : :
1250 : : /* Might be good enough to be worth trying, so let's try it. */
1251 : 47281 : add_partial_path(joinrel, (Path *)
1252 : 47281 : create_mergejoin_path(root,
1253 : : joinrel,
1254 : : jointype,
1255 : : &workspace,
1256 : : extra,
1257 : : outer_path,
1258 : : inner_path,
1259 : : extra->restrictlist,
1260 : : pathkeys,
1261 : : NULL,
1262 : : mergeclauses,
1263 : : outersortkeys,
1264 : : innersortkeys,
1265 : : outer_presorted_keys));
1266 : : }
1267 : :
1268 : : /*
1269 : : * try_hashjoin_path
1270 : : * Consider a hash join path; if it appears useful, push it into
1271 : : * the joinrel's pathlist via add_path().
1272 : : */
1273 : : static void
1274 : 611844 : try_hashjoin_path(PlannerInfo *root,
1275 : : RelOptInfo *joinrel,
1276 : : Path *outer_path,
1277 : : Path *inner_path,
1278 : : List *hashclauses,
1279 : : JoinType jointype,
1280 : : JoinPathExtraData *extra)
1281 : : {
1282 : : Relids required_outer;
1283 : : JoinCostWorkspace workspace;
1284 : :
1285 : : /*
1286 : : * If we are forming an outer join at this join, it's nonsensical to use
1287 : : * an input path that uses the outer join as part of its parameterization.
1288 : : * (This can happen despite our join order restrictions, since those apply
1289 : : * to what is in an input relation not what its parameters are.)
1290 : : */
1291 [ + + + + ]: 757295 : if (extra->sjinfo->ojrelid != 0 &&
1292 [ + + + + ]: 290877 : (bms_is_member(extra->sjinfo->ojrelid, PATH_REQ_OUTER(inner_path)) ||
1293 [ + + ]: 145426 : bms_is_member(extra->sjinfo->ojrelid, PATH_REQ_OUTER(outer_path))))
1294 : 83567 : return;
1295 : :
1296 : : /*
1297 : : * Check to see if proposed path is still parameterized, and reject if the
1298 : : * parameterization wouldn't be sensible.
1299 : : */
1300 : 611794 : required_outer = calc_non_nestloop_required_outer(outer_path,
1301 : : inner_path);
1302 [ + + ]: 611794 : if (required_outer &&
1303 [ + + ]: 95265 : !bms_overlap(required_outer, extra->param_source_rels))
1304 : : {
1305 : : /* Waste no memory when we reject a path here */
1306 : 83517 : bms_free(required_outer);
1307 : 83517 : return;
1308 : : }
1309 : :
1310 : : /*
1311 : : * See comments in try_nestloop_path(). Also note that hashjoin paths
1312 : : * never have any output pathkeys, per comments in create_hashjoin_path.
1313 : : */
1314 : 528277 : initial_cost_hashjoin(root, &workspace, jointype, hashclauses,
1315 : : outer_path, inner_path, extra, false);
1316 : :
1317 [ + + ]: 528277 : if (add_path_precheck(joinrel, workspace.disabled_nodes,
1318 : : workspace.startup_cost, workspace.total_cost,
1319 : : NIL, required_outer))
1320 : : {
1321 : 263043 : add_path(joinrel, (Path *)
1322 : 263043 : create_hashjoin_path(root,
1323 : : joinrel,
1324 : : jointype,
1325 : : &workspace,
1326 : : extra,
1327 : : outer_path,
1328 : : inner_path,
1329 : : false, /* parallel_hash */
1330 : : extra->restrictlist,
1331 : : required_outer,
1332 : : hashclauses));
1333 : : }
1334 : : else
1335 : : {
1336 : : /* Waste no memory when we reject a path here */
1337 : 265234 : bms_free(required_outer);
1338 : : }
1339 : : }
1340 : :
1341 : : /*
1342 : : * try_partial_hashjoin_path
1343 : : * Consider a partial hashjoin join path; if it appears useful, push it into
1344 : : * the joinrel's partial_pathlist via add_partial_path().
1345 : : * The outer side is partial. If parallel_hash is true, then the inner path
1346 : : * must be partial and will be run in parallel to create one or more shared
1347 : : * hash tables; otherwise the inner path must be complete and a copy of it
1348 : : * is run in every process to create separate identical private hash tables.
1349 : : */
1350 : : static void
1351 : 114152 : try_partial_hashjoin_path(PlannerInfo *root,
1352 : : RelOptInfo *joinrel,
1353 : : Path *outer_path,
1354 : : Path *inner_path,
1355 : : List *hashclauses,
1356 : : JoinType jointype,
1357 : : JoinPathExtraData *extra,
1358 : : bool parallel_hash)
1359 : : {
1360 : : JoinCostWorkspace workspace;
1361 : :
1362 : : /*
1363 : : * If the inner path is parameterized, we can't use a partial hashjoin.
1364 : : * Parameterized partial paths are not supported. The caller should
1365 : : * already have verified that no lateral rels are required here.
1366 : : */
1367 : : Assert(bms_is_empty(joinrel->lateral_relids));
1368 : : Assert(bms_is_empty(PATH_REQ_OUTER(outer_path)));
1369 [ - + - - ]: 114152 : if (!bms_is_empty(PATH_REQ_OUTER(inner_path)))
1370 : 32163 : return;
1371 : :
1372 : : /*
1373 : : * Before creating a path, get a quick lower bound on what it is likely to
1374 : : * cost. Bail out right away if it looks terrible.
1375 : : */
1376 : 114152 : initial_cost_hashjoin(root, &workspace, jointype, hashclauses,
1377 : : outer_path, inner_path, extra, parallel_hash);
1378 [ + + ]: 114152 : if (!add_partial_path_precheck(joinrel, workspace.disabled_nodes,
1379 : : workspace.startup_cost,
1380 : : workspace.total_cost, NIL))
1381 : 32163 : return;
1382 : :
1383 : : /* Might be good enough to be worth trying, so let's try it. */
1384 : 81989 : add_partial_path(joinrel, (Path *)
1385 : 81989 : create_hashjoin_path(root,
1386 : : joinrel,
1387 : : jointype,
1388 : : &workspace,
1389 : : extra,
1390 : : outer_path,
1391 : : inner_path,
1392 : : parallel_hash,
1393 : : extra->restrictlist,
1394 : : NULL,
1395 : : hashclauses));
1396 : : }
1397 : :
1398 : : /*
1399 : : * sort_inner_and_outer
1400 : : * Create mergejoin join paths by explicitly sorting both the outer and
1401 : : * inner join relations on each available merge ordering.
1402 : : *
1403 : : * 'joinrel' is the join relation
1404 : : * 'outerrel' is the outer join relation
1405 : : * 'innerrel' is the inner join relation
1406 : : * 'jointype' is the type of join to do
1407 : : * 'extra' contains additional input values
1408 : : */
1409 : : static void
1410 : 613234 : sort_inner_and_outer(PlannerInfo *root,
1411 : : RelOptInfo *joinrel,
1412 : : RelOptInfo *outerrel,
1413 : : RelOptInfo *innerrel,
1414 : : JoinType jointype,
1415 : : JoinPathExtraData *extra)
1416 : : {
1417 : : Path *outer_path;
1418 : : Path *inner_path;
1419 : 613234 : Path *cheapest_partial_outer = NULL;
1420 : 613234 : Path *cheapest_safe_inner = NULL;
1421 : : List *all_pathkeys;
1422 : : ListCell *l;
1423 : :
1424 : : /* Nothing to do if there are no available mergejoin clauses */
1425 [ + + ]: 613234 : if (extra->mergeclause_list == NIL)
1426 : 159778 : return;
1427 : :
1428 : : /*
1429 : : * We only consider the cheapest-total-cost input paths, since we are
1430 : : * assuming here that a sort is required. We will consider
1431 : : * cheapest-startup-cost input paths later, and only if they don't need a
1432 : : * sort.
1433 : : *
1434 : : * This function intentionally does not consider parameterized input
1435 : : * paths, except when the cheapest-total is parameterized. If we did so,
1436 : : * we'd have a combinatorial explosion of mergejoin paths of dubious
1437 : : * value. This interacts with decisions elsewhere that also discriminate
1438 : : * against mergejoins with parameterized inputs; see comments in
1439 : : * src/backend/optimizer/README.
1440 : : */
1441 : 453456 : outer_path = outerrel->cheapest_total_path;
1442 : 453456 : inner_path = innerrel->cheapest_total_path;
1443 : :
1444 : : /*
1445 : : * If either cheapest-total path is parameterized by the other rel, we
1446 : : * can't use a mergejoin. (There's no use looking for alternative input
1447 : : * paths, since these should already be the least-parameterized available
1448 : : * paths.)
1449 : : */
1450 [ + + + - : 453456 : if (PATH_PARAM_BY_REL(outer_path, innerrel) ||
+ + + + +
- + + ]
1451 [ + + + - : 451422 : PATH_PARAM_BY_REL(inner_path, outerrel))
+ + + + +
- + + ]
1452 : 4092 : return;
1453 : :
1454 : : /*
1455 : : * If the joinrel is parallel-safe, we may be able to consider a partial
1456 : : * merge join. However, we can't handle JOIN_FULL, JOIN_RIGHT and
1457 : : * JOIN_RIGHT_ANTI, because they can produce false null extended rows.
1458 : : * Also, the resulting path must not be parameterized.
1459 : : */
1460 [ + + + + ]: 449364 : if (joinrel->consider_parallel &&
1461 [ + + ]: 405909 : jointype != JOIN_FULL &&
1462 [ + + ]: 358563 : jointype != JOIN_RIGHT &&
1463 : 350945 : jointype != JOIN_RIGHT_ANTI &&
1464 [ + + ]: 350945 : outerrel->partial_pathlist != NIL &&
1465 [ + - ]: 52729 : bms_is_empty(joinrel->lateral_relids))
1466 : : {
1467 : 52729 : cheapest_partial_outer = (Path *) linitial(outerrel->partial_pathlist);
1468 : :
1469 [ + + ]: 52729 : if (inner_path->parallel_safe)
1470 : 52598 : cheapest_safe_inner = inner_path;
1471 : : else
1472 : : cheapest_safe_inner =
1473 : 131 : get_cheapest_parallel_safe_total_inner(innerrel->pathlist);
1474 : : }
1475 : :
1476 : : /*
1477 : : * Each possible ordering of the available mergejoin clauses will generate
1478 : : * a differently-sorted result path at essentially the same cost. We have
1479 : : * no basis for choosing one over another at this level of joining, but
1480 : : * some sort orders may be more useful than others for higher-level
1481 : : * mergejoins, so it's worth considering multiple orderings.
1482 : : *
1483 : : * Actually, it's not quite true that every mergeclause ordering will
1484 : : * generate a different path order, because some of the clauses may be
1485 : : * partially redundant (refer to the same EquivalenceClasses). Therefore,
1486 : : * what we do is convert the mergeclause list to a list of canonical
1487 : : * pathkeys, and then consider different orderings of the pathkeys.
1488 : : *
1489 : : * Generating a path for *every* permutation of the pathkeys doesn't seem
1490 : : * like a winning strategy; the cost in planning time is too high. For
1491 : : * now, we generate one path for each pathkey, listing that pathkey first
1492 : : * and the rest in random order. This should allow at least a one-clause
1493 : : * mergejoin without re-sorting against any other possible mergejoin
1494 : : * partner path. But if we've not guessed the right ordering of secondary
1495 : : * keys, we may end up evaluating clauses as qpquals when they could have
1496 : : * been done as mergeclauses. (In practice, it's rare that there's more
1497 : : * than two or three mergeclauses, so expending a huge amount of thought
1498 : : * on that is probably not worth it.)
1499 : : *
1500 : : * The pathkey order returned by select_outer_pathkeys_for_merge() has
1501 : : * some heuristics behind it (see that function), so be sure to try it
1502 : : * exactly as-is as well as making variants.
1503 : : */
1504 : 449364 : all_pathkeys = select_outer_pathkeys_for_merge(root,
1505 : : extra->mergeclause_list,
1506 : : joinrel);
1507 : :
1508 [ + - + + : 969237 : foreach(l, all_pathkeys)
+ + ]
1509 : : {
1510 : 519873 : PathKey *front_pathkey = (PathKey *) lfirst(l);
1511 : : List *cur_mergeclauses;
1512 : : List *outerkeys;
1513 : : List *innerkeys;
1514 : : List *merge_pathkeys;
1515 : :
1516 : : /* Make a pathkey list with this guy first */
1517 [ + + ]: 519873 : if (l != list_head(all_pathkeys))
1518 : 70509 : outerkeys = lcons(front_pathkey,
1519 : : list_delete_nth_cell(list_copy(all_pathkeys),
1520 : : foreach_current_index(l)));
1521 : : else
1522 : 449364 : outerkeys = all_pathkeys; /* no work at first one... */
1523 : :
1524 : : /* Sort the mergeclauses into the corresponding ordering */
1525 : : cur_mergeclauses =
1526 : 519873 : find_mergeclauses_for_outer_pathkeys(root,
1527 : : outerkeys,
1528 : : extra->mergeclause_list);
1529 : :
1530 : : /* Should have used them all... */
1531 : : Assert(list_length(cur_mergeclauses) == list_length(extra->mergeclause_list));
1532 : :
1533 : : /* Build sort pathkeys for the inner side */
1534 : 519873 : innerkeys = make_inner_pathkeys_for_merge(root,
1535 : : cur_mergeclauses,
1536 : : outerkeys);
1537 : :
1538 : : /* Build pathkeys representing output sort order */
1539 : 519873 : merge_pathkeys = build_join_pathkeys(root, joinrel, jointype,
1540 : : outerkeys);
1541 : :
1542 : : /*
1543 : : * And now we can make the path.
1544 : : *
1545 : : * Note: it's possible that the cheapest paths will already be sorted
1546 : : * properly. try_mergejoin_path will detect that case and suppress an
1547 : : * explicit sort step, so we needn't do so here.
1548 : : */
1549 : 519873 : try_mergejoin_path(root,
1550 : : joinrel,
1551 : : outer_path,
1552 : : inner_path,
1553 : : merge_pathkeys,
1554 : : cur_mergeclauses,
1555 : : outerkeys,
1556 : : innerkeys,
1557 : : jointype,
1558 : : extra,
1559 : : false);
1560 : :
1561 : : /*
1562 : : * If we have partial outer and parallel safe inner path then try
1563 : : * partial mergejoin path.
1564 : : */
1565 [ + + + + ]: 519873 : if (cheapest_partial_outer && cheapest_safe_inner)
1566 : 55312 : try_partial_mergejoin_path(root,
1567 : : joinrel,
1568 : : cheapest_partial_outer,
1569 : : cheapest_safe_inner,
1570 : : merge_pathkeys,
1571 : : cur_mergeclauses,
1572 : : outerkeys,
1573 : : innerkeys,
1574 : : jointype,
1575 : : extra);
1576 : : }
1577 : : }
1578 : :
1579 : : /*
1580 : : * generate_mergejoin_paths
1581 : : * Creates possible mergejoin paths for input outerpath.
1582 : : *
1583 : : * We generate mergejoins if mergejoin clauses are available. We have
1584 : : * two ways to generate the inner path for a mergejoin: sort the cheapest
1585 : : * inner path, or use an inner path that is already suitably ordered for the
1586 : : * merge. If we have several mergeclauses, it could be that there is no inner
1587 : : * path (or only a very expensive one) for the full list of mergeclauses, but
1588 : : * better paths exist if we truncate the mergeclause list (thereby discarding
1589 : : * some sort key requirements). So, we consider truncations of the
1590 : : * mergeclause list as well as the full list. (Ideally we'd consider all
1591 : : * subsets of the mergeclause list, but that seems way too expensive.)
1592 : : */
1593 : : static void
1594 : 1212217 : generate_mergejoin_paths(PlannerInfo *root,
1595 : : RelOptInfo *joinrel,
1596 : : RelOptInfo *innerrel,
1597 : : Path *outerpath,
1598 : : JoinType jointype,
1599 : : JoinPathExtraData *extra,
1600 : : bool useallclauses,
1601 : : Path *inner_cheapest_total,
1602 : : List *merge_pathkeys,
1603 : : bool is_partial)
1604 : : {
1605 : : List *mergeclauses;
1606 : : List *innersortkeys;
1607 : : List *trialsortkeys;
1608 : : Path *cheapest_startup_inner;
1609 : : Path *cheapest_total_inner;
1610 : : int num_sortkeys;
1611 : : int sortkeycnt;
1612 : :
1613 : : /* Look for useful mergeclauses (if any) */
1614 : : mergeclauses =
1615 : 1212217 : find_mergeclauses_for_outer_pathkeys(root,
1616 : : outerpath->pathkeys,
1617 : : extra->mergeclause_list);
1618 : :
1619 : : /*
1620 : : * Done with this outer path if no chance for a mergejoin.
1621 : : *
1622 : : * Special corner case: for "x FULL JOIN y ON true", there will be no join
1623 : : * clauses at all. Ordinarily we'd generate a clauseless nestloop path,
1624 : : * but since mergejoin is our only join type that supports FULL JOIN
1625 : : * without any join clauses, it's necessary to generate a clauseless
1626 : : * mergejoin path instead.
1627 : : */
1628 [ + + ]: 1212217 : if (mergeclauses == NIL)
1629 : : {
1630 [ + + ]: 863663 : if (jointype == JOIN_FULL)
1631 : : /* okay to try for mergejoin */ ;
1632 : : else
1633 : 860933 : return;
1634 : : }
1635 [ + + + + ]: 409712 : if (useallclauses &&
1636 : 58428 : list_length(mergeclauses) != list_length(extra->mergeclause_list))
1637 : 8168 : return;
1638 : :
1639 : : /* Compute the required ordering of the inner path */
1640 : 343116 : innersortkeys = make_inner_pathkeys_for_merge(root,
1641 : : mergeclauses,
1642 : : outerpath->pathkeys);
1643 : :
1644 : : /*
1645 : : * Generate a mergejoin on the basis of sorting the cheapest inner. Since
1646 : : * a sort will be needed, only cheapest total cost matters. (But
1647 : : * try_mergejoin_path will do the right thing if inner_cheapest_total is
1648 : : * already correctly sorted.)
1649 : : */
1650 : 343116 : try_mergejoin_path(root,
1651 : : joinrel,
1652 : : outerpath,
1653 : : inner_cheapest_total,
1654 : : merge_pathkeys,
1655 : : mergeclauses,
1656 : : NIL,
1657 : : innersortkeys,
1658 : : jointype,
1659 : : extra,
1660 : : is_partial);
1661 : :
1662 : : /*
1663 : : * Look for presorted inner paths that satisfy the innersortkey list ---
1664 : : * or any truncation thereof, if we are allowed to build a mergejoin using
1665 : : * a subset of the merge clauses. Here, we consider both cheap startup
1666 : : * cost and cheap total cost.
1667 : : *
1668 : : * Currently we do not consider parameterized inner paths here. This
1669 : : * interacts with decisions elsewhere that also discriminate against
1670 : : * mergejoins with parameterized inputs; see comments in
1671 : : * src/backend/optimizer/README.
1672 : : *
1673 : : * As we shorten the sortkey list, we should consider only paths that are
1674 : : * strictly cheaper than (in particular, not the same as) any path found
1675 : : * in an earlier iteration. Otherwise we'd be intentionally using fewer
1676 : : * merge keys than a given path allows (treating the rest as plain
1677 : : * joinquals), which is unlikely to be a good idea. Also, eliminating
1678 : : * paths here on the basis of compare_path_costs is a lot cheaper than
1679 : : * building the mergejoin path only to throw it away.
1680 : : *
1681 : : * If inner_cheapest_total is well enough sorted to have not required a
1682 : : * sort in the path made above, we shouldn't make a duplicate path with
1683 : : * it, either. We handle that case with the same logic that handles the
1684 : : * previous consideration, by initializing the variables that track
1685 : : * cheapest-so-far properly. Note that we do NOT reject
1686 : : * inner_cheapest_total if we find it matches some shorter set of
1687 : : * pathkeys. That case corresponds to using fewer mergekeys to avoid
1688 : : * sorting inner_cheapest_total, whereas we did sort it above, so the
1689 : : * plans being considered are different.
1690 : : */
1691 [ + + ]: 343116 : if (pathkeys_contained_in(innersortkeys,
1692 : : inner_cheapest_total->pathkeys))
1693 : : {
1694 : : /* inner_cheapest_total didn't require a sort */
1695 : 9960 : cheapest_startup_inner = inner_cheapest_total;
1696 : 9960 : cheapest_total_inner = inner_cheapest_total;
1697 : : }
1698 : : else
1699 : : {
1700 : : /* it did require a sort, at least for the full set of keys */
1701 : 333156 : cheapest_startup_inner = NULL;
1702 : 333156 : cheapest_total_inner = NULL;
1703 : : }
1704 : 343116 : num_sortkeys = list_length(innersortkeys);
1705 [ + + + + ]: 343116 : if (num_sortkeys > 1 && !useallclauses)
1706 : 19264 : trialsortkeys = list_copy(innersortkeys); /* need modifiable copy */
1707 : : else
1708 : 323852 : trialsortkeys = innersortkeys; /* won't really truncate */
1709 : :
1710 [ + + ]: 655721 : for (sortkeycnt = num_sortkeys; sortkeycnt > 0; sortkeycnt--)
1711 : : {
1712 : : Path *innerpath;
1713 : 362753 : List *newclauses = NIL;
1714 : :
1715 : : /*
1716 : : * Look for an inner path ordered well enough for the first
1717 : : * 'sortkeycnt' innersortkeys. NB: trialsortkeys list is modified
1718 : : * destructively, which is why we made a copy...
1719 : : */
1720 : 362753 : trialsortkeys = list_truncate(trialsortkeys, sortkeycnt);
1721 : 362753 : innerpath = get_cheapest_path_for_pathkeys(innerrel->pathlist,
1722 : : trialsortkeys,
1723 : : NULL,
1724 : : TOTAL_COST,
1725 : : is_partial);
1726 [ + + + + ]: 362753 : if (innerpath != NULL &&
1727 [ + + ]: 17120 : (cheapest_total_inner == NULL ||
1728 : 17120 : compare_path_costs(innerpath, cheapest_total_inner,
1729 : : TOTAL_COST) < 0))
1730 : : {
1731 : : /* Found a cheap (or even-cheaper) sorted path */
1732 : : /* Select the right mergeclauses, if we didn't already */
1733 [ + + ]: 197614 : if (sortkeycnt < num_sortkeys)
1734 : : {
1735 : : newclauses =
1736 : 8690 : trim_mergeclauses_for_inner_pathkeys(root,
1737 : : mergeclauses,
1738 : : trialsortkeys);
1739 : : Assert(newclauses != NIL);
1740 : : }
1741 : : else
1742 : 188924 : newclauses = mergeclauses;
1743 : 197614 : try_mergejoin_path(root,
1744 : : joinrel,
1745 : : outerpath,
1746 : : innerpath,
1747 : : merge_pathkeys,
1748 : : newclauses,
1749 : : NIL,
1750 : : NIL,
1751 : : jointype,
1752 : : extra,
1753 : : is_partial);
1754 : 197614 : cheapest_total_inner = innerpath;
1755 : : }
1756 : : /* Same on the basis of cheapest startup cost ... */
1757 : 362753 : innerpath = get_cheapest_path_for_pathkeys(innerrel->pathlist,
1758 : : trialsortkeys,
1759 : : NULL,
1760 : : STARTUP_COST,
1761 : : is_partial);
1762 [ + + + + ]: 362753 : if (innerpath != NULL &&
1763 [ + + ]: 17120 : (cheapest_startup_inner == NULL ||
1764 : 17120 : compare_path_costs(innerpath, cheapest_startup_inner,
1765 : : STARTUP_COST) < 0))
1766 : : {
1767 : : /* Found a cheap (or even-cheaper) sorted path */
1768 [ + + ]: 195813 : if (innerpath != cheapest_total_inner)
1769 : : {
1770 : : /*
1771 : : * Avoid rebuilding clause list if we already made one; saves
1772 : : * memory in big join trees...
1773 : : */
1774 [ + + ]: 1816 : if (newclauses == NIL)
1775 : : {
1776 [ - + ]: 41 : if (sortkeycnt < num_sortkeys)
1777 : : {
1778 : : newclauses =
1779 : 0 : trim_mergeclauses_for_inner_pathkeys(root,
1780 : : mergeclauses,
1781 : : trialsortkeys);
1782 : : Assert(newclauses != NIL);
1783 : : }
1784 : : else
1785 : 41 : newclauses = mergeclauses;
1786 : : }
1787 : 1816 : try_mergejoin_path(root,
1788 : : joinrel,
1789 : : outerpath,
1790 : : innerpath,
1791 : : merge_pathkeys,
1792 : : newclauses,
1793 : : NIL,
1794 : : NIL,
1795 : : jointype,
1796 : : extra,
1797 : : is_partial);
1798 : : }
1799 : 195813 : cheapest_startup_inner = innerpath;
1800 : : }
1801 : :
1802 : : /*
1803 : : * Don't consider truncated sortkeys if we need all clauses.
1804 : : */
1805 [ + + ]: 362753 : if (useallclauses)
1806 : 50148 : break;
1807 : : }
1808 : : }
1809 : :
1810 : : /*
1811 : : * match_unsorted_outer
1812 : : * Creates possible join paths for processing a single join relation
1813 : : * 'joinrel' by employing either iterative substitution or
1814 : : * mergejoining on each of its possible outer paths (considering
1815 : : * only outer paths that are already ordered well enough for merging).
1816 : : *
1817 : : * We always generate a nestloop path for each available outer path.
1818 : : * In fact we may generate as many as five: one on the cheapest-total-cost
1819 : : * inner path, one on the same with materialization, one on the
1820 : : * cheapest-startup-cost inner path (if different), one on the
1821 : : * cheapest-total inner-indexscan path (if any), and one on the
1822 : : * cheapest-startup inner-indexscan path (if different).
1823 : : *
1824 : : * We also consider mergejoins if mergejoin clauses are available. See
1825 : : * detailed comments in generate_mergejoin_paths.
1826 : : *
1827 : : * 'joinrel' is the join relation
1828 : : * 'outerrel' is the outer join relation
1829 : : * 'innerrel' is the inner join relation
1830 : : * 'jointype' is the type of join to do
1831 : : * 'extra' contains additional input values
1832 : : */
1833 : : static void
1834 : 613234 : match_unsorted_outer(PlannerInfo *root,
1835 : : RelOptInfo *joinrel,
1836 : : RelOptInfo *outerrel,
1837 : : RelOptInfo *innerrel,
1838 : : JoinType jointype,
1839 : : JoinPathExtraData *extra)
1840 : : {
1841 : : bool nestjoinOK;
1842 : : bool useallclauses;
1843 : 613234 : Path *inner_cheapest_total = innerrel->cheapest_total_path;
1844 : 613234 : Path *matpath = NULL;
1845 : : ListCell *lc1;
1846 : :
1847 : : /*
1848 : : * For now we do not support RIGHT_SEMI join in mergejoin or nestloop
1849 : : * join.
1850 : : */
1851 [ + + ]: 613234 : if (jointype == JOIN_RIGHT_SEMI)
1852 : 1116 : return;
1853 : :
1854 : : /*
1855 : : * Nestloop only supports inner, left, semi, and anti joins. Also, if we
1856 : : * are doing a right, right-anti or full mergejoin, we must use *all* the
1857 : : * mergeclauses as join clauses, else we will not have a valid plan.
1858 : : * (Although these two flags are currently inverses, keep them separate
1859 : : * for clarity and possible future changes.)
1860 : : */
1861 [ + + - ]: 612118 : switch (jointype)
1862 : : {
1863 : 540395 : case JOIN_INNER:
1864 : : case JOIN_LEFT:
1865 : : case JOIN_SEMI:
1866 : : case JOIN_ANTI:
1867 : 540395 : nestjoinOK = true;
1868 : 540395 : useallclauses = false;
1869 : 540395 : break;
1870 : 71723 : case JOIN_RIGHT:
1871 : : case JOIN_RIGHT_ANTI:
1872 : : case JOIN_FULL:
1873 : 71723 : nestjoinOK = false;
1874 : 71723 : useallclauses = true;
1875 : 71723 : break;
1876 : 0 : default:
1877 [ # # ]: 0 : elog(ERROR, "unrecognized join type: %d",
1878 : : (int) jointype);
1879 : : nestjoinOK = false; /* keep compiler quiet */
1880 : : useallclauses = false;
1881 : : break;
1882 : : }
1883 : :
1884 : : /*
1885 : : * If inner_cheapest_total is parameterized by the outer rel, ignore it;
1886 : : * we will consider it below as a member of cheapest_parameterized_paths,
1887 : : * but the other possibilities considered in this routine aren't usable.
1888 : : *
1889 : : * Furthermore, if the inner side is a unique-ified relation, we cannot
1890 : : * generate any valid paths here, because the inner rel's dependency on
1891 : : * the outer rel makes unique-ification meaningless.
1892 : : */
1893 [ + + + - : 612118 : if (PATH_PARAM_BY_REL(inner_cheapest_total, outerrel))
+ + + + +
- + + ]
1894 : : {
1895 : 12195 : inner_cheapest_total = NULL;
1896 : :
1897 [ + + + + : 12195 : if (RELATION_WAS_MADE_UNIQUE(innerrel, extra->sjinfo, jointype))
+ - ]
1898 : 30 : return;
1899 : : }
1900 : :
1901 [ + + ]: 612088 : if (nestjoinOK)
1902 : : {
1903 : : /*
1904 : : * Consider materializing the cheapest inner path, unless that is
1905 : : * disabled or the path in question materializes its output anyway.
1906 : : *
1907 : : * At present, we only consider materialization for non-partial outer
1908 : : * paths, so it's correct to test PGS_CONSIDER_NONPARTIAL here. If we
1909 : : * ever want to consider materialization for partial paths, we'll need
1910 : : * to create matpath whenever PGS_NESTLOOP_MATERIALIZE is set, use it
1911 : : * for partial paths either way, and use it for non-partial paths only
1912 : : * when PGS_CONSIDER_NONPARTIAL is also set.
1913 : : */
1914 [ + + ]: 540365 : if ((extra->pgs_mask &
1915 : : (PGS_NESTLOOP_MATERIALIZE | PGS_CONSIDER_NONPARTIAL)) ==
1916 [ + + ]: 470208 : (PGS_NESTLOOP_MATERIALIZE | PGS_CONSIDER_NONPARTIAL) &&
1917 : 458934 : inner_cheapest_total != NULL &&
1918 [ + + ]: 458934 : !ExecMaterializesOutput(inner_cheapest_total->pathtype))
1919 : : matpath = (Path *)
1920 : 443942 : create_material_path(innerrel, inner_cheapest_total, true);
1921 : : }
1922 : :
1923 [ + - + + : 1974024 : foreach(lc1, outerrel->pathlist)
+ + ]
1924 : : {
1925 : 1361936 : Path *outerpath = (Path *) lfirst(lc1);
1926 : : List *merge_pathkeys;
1927 : :
1928 : : /*
1929 : : * We cannot use an outer path that is parameterized by the inner rel.
1930 : : */
1931 [ + + + - : 1361936 : if (PATH_PARAM_BY_REL(outerpath, innerrel))
+ + + + +
- + + ]
1932 : 208950 : continue;
1933 : :
1934 : : /*
1935 : : * The result will have this sort order (even if it is implemented as
1936 : : * a nestloop, and even if some of the mergeclauses are implemented by
1937 : : * qpquals rather than as true mergeclauses):
1938 : : */
1939 : 1152986 : merge_pathkeys = build_join_pathkeys(root, joinrel, jointype,
1940 : : outerpath->pathkeys);
1941 : :
1942 [ + + ]: 1152986 : if (nestjoinOK)
1943 : : {
1944 : : /*
1945 : : * Consider nestloop joins using this outer path and various
1946 : : * available paths for the inner relation. We consider the
1947 : : * cheapest-total paths for each available parameterization of the
1948 : : * inner relation, including the unparameterized case.
1949 : : */
1950 : : ListCell *lc2;
1951 : :
1952 [ + - + + : 2587836 : foreach(lc2, innerrel->cheapest_parameterized_paths)
+ + ]
1953 : : {
1954 : 1566094 : Path *innerpath = (Path *) lfirst(lc2);
1955 : : Path *mpath;
1956 : :
1957 : 1566094 : try_nestloop_path(root,
1958 : : joinrel,
1959 : : outerpath,
1960 : : innerpath,
1961 : : merge_pathkeys,
1962 : : jointype,
1963 : : PGS_NESTLOOP_PLAIN,
1964 : : extra);
1965 : :
1966 : : /*
1967 : : * Try generating a memoize path and see if that makes the
1968 : : * nested loop any cheaper.
1969 : : */
1970 : 1566094 : mpath = get_memoize_path(root, innerrel, outerrel,
1971 : : innerpath, outerpath, jointype,
1972 : : extra);
1973 [ + + ]: 1566094 : if (mpath != NULL)
1974 : 203627 : try_nestloop_path(root,
1975 : : joinrel,
1976 : : outerpath,
1977 : : mpath,
1978 : : merge_pathkeys,
1979 : : jointype,
1980 : : PGS_NESTLOOP_MEMOIZE,
1981 : : extra);
1982 : : }
1983 : :
1984 : : /* Also consider materialized form of the cheapest inner path */
1985 [ + + ]: 1021742 : if (matpath != NULL)
1986 : 855335 : try_nestloop_path(root,
1987 : : joinrel,
1988 : : outerpath,
1989 : : matpath,
1990 : : merge_pathkeys,
1991 : : jointype,
1992 : : PGS_NESTLOOP_MATERIALIZE,
1993 : : extra);
1994 : : }
1995 : :
1996 : : /* Can't do anything else if inner rel is parameterized by outer */
1997 [ + + ]: 1152986 : if (inner_cheapest_total == NULL)
1998 : 19654 : continue;
1999 : :
2000 : : /* Generate merge join paths */
2001 : 1133332 : generate_mergejoin_paths(root, joinrel, innerrel, outerpath,
2002 : : jointype, extra, useallclauses,
2003 : : inner_cheapest_total, merge_pathkeys,
2004 : : false);
2005 : : }
2006 : :
2007 : : /*
2008 : : * Consider partial nestloop and mergejoin plan if outerrel has any
2009 : : * partial path and the joinrel is parallel-safe. However, we can't
2010 : : * handle joins needing lateral rels, since partial paths must not be
2011 : : * parameterized. Similarly, we can't handle JOIN_FULL, JOIN_RIGHT and
2012 : : * JOIN_RIGHT_ANTI, because they can produce false null extended rows.
2013 : : */
2014 [ + + + + ]: 612088 : if (joinrel->consider_parallel &&
2015 [ + + ]: 528222 : jointype != JOIN_FULL &&
2016 [ + + ]: 474450 : jointype != JOIN_RIGHT &&
2017 : 465045 : jointype != JOIN_RIGHT_ANTI &&
2018 [ + + ]: 465045 : outerrel->partial_pathlist != NIL &&
2019 [ + - ]: 62969 : bms_is_empty(joinrel->lateral_relids))
2020 : : {
2021 [ + - ]: 62969 : if (nestjoinOK)
2022 : 62969 : consider_parallel_nestloop(root, joinrel, outerrel, innerrel,
2023 : : jointype, extra);
2024 : :
2025 : : /*
2026 : : * If inner_cheapest_total is NULL or non parallel-safe then find the
2027 : : * cheapest total parallel safe path.
2028 : : */
2029 [ + + ]: 62969 : if (inner_cheapest_total == NULL ||
2030 [ + + ]: 62619 : !inner_cheapest_total->parallel_safe)
2031 : : {
2032 : : inner_cheapest_total =
2033 : 690 : get_cheapest_parallel_safe_total_inner(innerrel->pathlist);
2034 : : }
2035 : :
2036 [ + + ]: 62969 : if (inner_cheapest_total)
2037 : 62587 : consider_parallel_mergejoin(root, joinrel, outerrel, innerrel,
2038 : : jointype, extra,
2039 : : inner_cheapest_total);
2040 : : }
2041 : : }
2042 : :
2043 : : /*
2044 : : * consider_parallel_mergejoin
2045 : : * Try to build partial paths for a joinrel by joining a partial path
2046 : : * for the outer relation to a complete path for the inner relation.
2047 : : *
2048 : : * 'joinrel' is the join relation
2049 : : * 'outerrel' is the outer join relation
2050 : : * 'innerrel' is the inner join relation
2051 : : * 'jointype' is the type of join to do
2052 : : * 'extra' contains additional input values
2053 : : * 'inner_cheapest_total' cheapest total path for innerrel
2054 : : */
2055 : : static void
2056 : 62587 : consider_parallel_mergejoin(PlannerInfo *root,
2057 : : RelOptInfo *joinrel,
2058 : : RelOptInfo *outerrel,
2059 : : RelOptInfo *innerrel,
2060 : : JoinType jointype,
2061 : : JoinPathExtraData *extra,
2062 : : Path *inner_cheapest_total)
2063 : : {
2064 : : ListCell *lc1;
2065 : :
2066 : : /* generate merge join path for each partial outer path */
2067 [ + - + + : 141472 : foreach(lc1, outerrel->partial_pathlist)
+ + ]
2068 : : {
2069 : 78885 : Path *outerpath = (Path *) lfirst(lc1);
2070 : : List *merge_pathkeys;
2071 : :
2072 : : /*
2073 : : * Figure out what useful ordering any paths we create will have.
2074 : : */
2075 : 78885 : merge_pathkeys = build_join_pathkeys(root, joinrel, jointype,
2076 : : outerpath->pathkeys);
2077 : :
2078 : 78885 : generate_mergejoin_paths(root, joinrel, innerrel, outerpath, jointype,
2079 : : extra, false, inner_cheapest_total,
2080 : : merge_pathkeys, true);
2081 : : }
2082 : 62587 : }
2083 : :
2084 : : /*
2085 : : * consider_parallel_nestloop
2086 : : * Try to build partial paths for a joinrel by joining a partial path for the
2087 : : * outer relation to a complete path for the inner relation.
2088 : : *
2089 : : * 'joinrel' is the join relation
2090 : : * 'outerrel' is the outer join relation
2091 : : * 'innerrel' is the inner join relation
2092 : : * 'jointype' is the type of join to do
2093 : : * 'extra' contains additional input values
2094 : : */
2095 : : static void
2096 : 62969 : consider_parallel_nestloop(PlannerInfo *root,
2097 : : RelOptInfo *joinrel,
2098 : : RelOptInfo *outerrel,
2099 : : RelOptInfo *innerrel,
2100 : : JoinType jointype,
2101 : : JoinPathExtraData *extra)
2102 : : {
2103 : 62969 : Path *inner_cheapest_total = innerrel->cheapest_total_path;
2104 : 62969 : Path *matpath = NULL;
2105 : : ListCell *lc1;
2106 : :
2107 : : /*
2108 : : * Consider materializing the cheapest inner path, unless: 1)
2109 : : * materialization is disabled here, 2) the cheapest inner path is not
2110 : : * parallel-safe, 3) the cheapest inner path is parameterized by the outer
2111 : : * rel, or 4) the cheapest inner path materializes its output anyway.
2112 : : */
2113 [ + + ]: 62969 : if ((extra->pgs_mask & PGS_NESTLOOP_MATERIALIZE) != 0 &&
2114 [ + + ]: 53595 : inner_cheapest_total->parallel_safe &&
2115 [ + + + - : 53394 : !PATH_PARAM_BY_REL(inner_cheapest_total, outerrel) &&
+ + + + +
- - + ]
2116 [ + + ]: 53134 : !ExecMaterializesOutput(inner_cheapest_total->pathtype))
2117 : : {
2118 : : matpath = (Path *)
2119 : 53070 : create_material_path(innerrel, inner_cheapest_total, true);
2120 : : Assert(matpath->parallel_safe);
2121 : : }
2122 : :
2123 [ + - + + : 142351 : foreach(lc1, outerrel->partial_pathlist)
+ + ]
2124 : : {
2125 : 79382 : Path *outerpath = (Path *) lfirst(lc1);
2126 : : List *pathkeys;
2127 : : ListCell *lc2;
2128 : :
2129 : : /* Figure out what useful ordering any paths we create will have. */
2130 : 79382 : pathkeys = build_join_pathkeys(root, joinrel, jointype,
2131 : : outerpath->pathkeys);
2132 : :
2133 : : /*
2134 : : * Try the cheapest parameterized paths; only those which will produce
2135 : : * an unparameterized path when joined to this outerrel will survive
2136 : : * try_partial_nestloop_path. The cheapest unparameterized path is
2137 : : * also in this list.
2138 : : */
2139 [ + - + + : 166683 : foreach(lc2, innerrel->cheapest_parameterized_paths)
+ + ]
2140 : : {
2141 : 87301 : Path *innerpath = (Path *) lfirst(lc2);
2142 : : Path *mpath;
2143 : :
2144 : : /* Can't join to an inner path that is not parallel-safe */
2145 [ + + ]: 87301 : if (!innerpath->parallel_safe)
2146 : 399 : continue;
2147 : :
2148 : 86902 : try_partial_nestloop_path(root, joinrel, outerpath, innerpath,
2149 : : pathkeys, jointype,
2150 : : PGS_NESTLOOP_PLAIN, extra);
2151 : :
2152 : : /*
2153 : : * Try generating a memoize path and see if that makes the nested
2154 : : * loop any cheaper.
2155 : : */
2156 : 86902 : mpath = get_memoize_path(root, innerrel, outerrel,
2157 : : innerpath, outerpath, jointype,
2158 : : extra);
2159 [ + + ]: 86902 : if (mpath != NULL)
2160 : 4023 : try_partial_nestloop_path(root, joinrel, outerpath, mpath,
2161 : : pathkeys, jointype,
2162 : : PGS_NESTLOOP_MEMOIZE, extra);
2163 : : }
2164 : :
2165 : : /* Also consider materialized form of the cheapest inner path */
2166 [ + + ]: 79382 : if (matpath != NULL)
2167 : 67050 : try_partial_nestloop_path(root, joinrel, outerpath, matpath,
2168 : : pathkeys, jointype,
2169 : : PGS_NESTLOOP_MATERIALIZE, extra);
2170 : : }
2171 : 62969 : }
2172 : :
2173 : : /*
2174 : : * hash_inner_and_outer
2175 : : * Create hashjoin join paths by explicitly hashing both the outer and
2176 : : * inner keys of each available hash clause.
2177 : : *
2178 : : * 'joinrel' is the join relation
2179 : : * 'outerrel' is the outer join relation
2180 : : * 'innerrel' is the inner join relation
2181 : : * 'jointype' is the type of join to do
2182 : : * 'extra' contains additional input values
2183 : : */
2184 : : static void
2185 : 550542 : hash_inner_and_outer(PlannerInfo *root,
2186 : : RelOptInfo *joinrel,
2187 : : RelOptInfo *outerrel,
2188 : : RelOptInfo *innerrel,
2189 : : JoinType jointype,
2190 : : JoinPathExtraData *extra)
2191 : : {
2192 : 550542 : bool isouterjoin = IS_OUTER_JOIN(jointype);
2193 : : List *hashclauses;
2194 : : ListCell *l;
2195 : :
2196 : : /*
2197 : : * We need to build only one hashclauses list for any given pair of outer
2198 : : * and inner relations; all of the hashable clauses will be used as keys.
2199 : : *
2200 : : * Scan the join's restrictinfo list to find hashjoinable clauses that are
2201 : : * usable with this pair of sub-relations.
2202 : : */
2203 : 550542 : hashclauses = NIL;
2204 [ + + + + : 1160894 : foreach(l, extra->restrictlist)
+ + ]
2205 : : {
2206 : 610352 : RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(l);
2207 : :
2208 : : /*
2209 : : * If processing an outer join, only use its own join clauses for
2210 : : * hashing. For inner joins we need not be so picky.
2211 : : */
2212 [ + + + + : 610352 : if (isouterjoin && RINFO_IS_PUSHED_DOWN(restrictinfo, joinrel->relids))
- + ]
2213 : 10835 : continue;
2214 : :
2215 [ + + ]: 599517 : if (!restrictinfo->can_join ||
2216 [ + + ]: 550320 : restrictinfo->hashjoinoperator == InvalidOid)
2217 : 59390 : continue; /* not hashjoinable */
2218 : :
2219 : : /*
2220 : : * Check if clause has the form "outer op inner" or "inner op outer".
2221 : : */
2222 [ + + ]: 540127 : if (!clause_sides_match_join(restrictinfo, outerrel->relids,
2223 : : innerrel->relids))
2224 : 144 : continue; /* no good for these input relations */
2225 : :
2226 : : /*
2227 : : * If clause has the form "inner op outer", check if its operator has
2228 : : * valid commutator. This is necessary because hashclauses in this
2229 : : * form will get commuted in createplan.c to put the outer var on the
2230 : : * left (see get_switched_clauses). This probably shouldn't ever
2231 : : * fail, since hashable operators ought to have commutators, but be
2232 : : * paranoid.
2233 : : *
2234 : : * The clause being hashjoinable indicates that it's an OpExpr.
2235 : : */
2236 [ + + + + ]: 809337 : if (!restrictinfo->outer_is_left &&
2237 : 269354 : !OidIsValid(get_commutator(castNode(OpExpr, restrictinfo->clause)->opno)))
2238 : 5 : continue;
2239 : :
2240 : 539978 : hashclauses = lappend(hashclauses, restrictinfo);
2241 : : }
2242 : :
2243 : : /* If we found any usable hashclauses, make paths */
2244 [ + + ]: 550542 : if (hashclauses)
2245 : : {
2246 : : /*
2247 : : * We consider both the cheapest-total-cost and cheapest-startup-cost
2248 : : * outer paths. There's no need to consider any but the
2249 : : * cheapest-total-cost inner path, however.
2250 : : */
2251 : 468630 : Path *cheapest_startup_outer = outerrel->cheapest_startup_path;
2252 : 468630 : Path *cheapest_total_outer = outerrel->cheapest_total_path;
2253 : 468630 : Path *cheapest_total_inner = innerrel->cheapest_total_path;
2254 : : ListCell *lc1;
2255 : : ListCell *lc2;
2256 : :
2257 : : /*
2258 : : * If either cheapest-total path is parameterized by the other rel, we
2259 : : * can't use a hashjoin. (There's no use looking for alternative
2260 : : * input paths, since these should already be the least-parameterized
2261 : : * available paths.)
2262 : : */
2263 [ + + + - : 468630 : if (PATH_PARAM_BY_REL(cheapest_total_outer, innerrel) ||
+ + + + +
- + + ]
2264 [ + + + - : 466588 : PATH_PARAM_BY_REL(cheapest_total_inner, outerrel))
+ + + + +
- + + ]
2265 : 4084 : return;
2266 : :
2267 : : /*
2268 : : * Consider the cheapest startup outer together with the cheapest
2269 : : * total inner, and then consider pairings of cheapest-total paths
2270 : : * including parameterized ones. There is no use in generating
2271 : : * parameterized paths on the basis of possibly cheap startup cost, so
2272 : : * this is sufficient.
2273 : : */
2274 [ + + ]: 464546 : if (cheapest_startup_outer != NULL)
2275 : 462745 : try_hashjoin_path(root,
2276 : : joinrel,
2277 : : cheapest_startup_outer,
2278 : : cheapest_total_inner,
2279 : : hashclauses,
2280 : : jointype,
2281 : : extra);
2282 : :
2283 [ + - + + : 1150129 : foreach(lc1, outerrel->cheapest_parameterized_paths)
+ + ]
2284 : : {
2285 : 685583 : Path *outerpath = (Path *) lfirst(lc1);
2286 : :
2287 : : /*
2288 : : * We cannot use an outer path that is parameterized by the inner
2289 : : * rel.
2290 : : */
2291 [ + + + - : 685583 : if (PATH_PARAM_BY_REL(outerpath, innerrel))
+ + + + +
- + + ]
2292 : 180129 : continue;
2293 : :
2294 [ + - + + : 1263181 : foreach(lc2, innerrel->cheapest_parameterized_paths)
+ + ]
2295 : : {
2296 : 757727 : Path *innerpath = (Path *) lfirst(lc2);
2297 : :
2298 : : /*
2299 : : * We cannot use an inner path that is parameterized by the
2300 : : * outer rel, either.
2301 : : */
2302 [ + + + - : 757727 : if (PATH_PARAM_BY_REL(innerpath, outerrel))
+ + + + +
- + + ]
2303 : 201519 : continue;
2304 : :
2305 [ + + + + ]: 556208 : if (outerpath == cheapest_startup_outer &&
2306 : : innerpath == cheapest_total_inner)
2307 : 407109 : continue; /* already tried it */
2308 : :
2309 : 149099 : try_hashjoin_path(root,
2310 : : joinrel,
2311 : : outerpath,
2312 : : innerpath,
2313 : : hashclauses,
2314 : : jointype,
2315 : : extra);
2316 : : }
2317 : : }
2318 : :
2319 : : /*
2320 : : * If the joinrel is parallel-safe, we may be able to consider a
2321 : : * partial hash join.
2322 : : *
2323 : : * However, we can't handle JOIN_RIGHT_SEMI, because the hash table is
2324 : : * either a shared hash table or a private hash table per backend. In
2325 : : * the shared case, there is no concurrency protection for the match
2326 : : * flags, so multiple workers could inspect and set the flags
2327 : : * concurrently, potentially producing incorrect results. In the
2328 : : * private case, each worker has its own copy of the hash table, so no
2329 : : * single process has all the match flags.
2330 : : *
2331 : : * Also, the resulting path must not be parameterized.
2332 : : */
2333 [ + + + + ]: 464546 : if (joinrel->consider_parallel &&
2334 : 418631 : jointype != JOIN_RIGHT_SEMI &&
2335 [ + + ]: 418631 : outerrel->partial_pathlist != NIL &&
2336 [ + - ]: 59482 : bms_is_empty(joinrel->lateral_relids))
2337 : : {
2338 : : Path *cheapest_partial_outer;
2339 : 59482 : Path *cheapest_partial_inner = NULL;
2340 : 59482 : Path *cheapest_safe_inner = NULL;
2341 : :
2342 : 59482 : cheapest_partial_outer =
2343 : 59482 : (Path *) linitial(outerrel->partial_pathlist);
2344 : :
2345 : : /*
2346 : : * Can we use a partial inner plan too, so that we can build a
2347 : : * shared hash table in parallel?
2348 : : */
2349 [ + + + + ]: 59482 : if (innerrel->partial_pathlist != NIL &&
2350 : : enable_parallel_hash)
2351 : : {
2352 : 57942 : cheapest_partial_inner =
2353 : 57942 : (Path *) linitial(innerrel->partial_pathlist);
2354 : 57942 : try_partial_hashjoin_path(root, joinrel,
2355 : : cheapest_partial_outer,
2356 : : cheapest_partial_inner,
2357 : : hashclauses, jointype, extra,
2358 : : true /* parallel_hash */ );
2359 : : }
2360 : :
2361 : : /*
2362 : : * Normally, given that the joinrel is parallel-safe, the cheapest
2363 : : * total inner path will also be parallel-safe, but if not, we'll
2364 : : * have to search for the cheapest safe, unparameterized inner
2365 : : * path. If full, right, or right-anti join, we can't use
2366 : : * parallelism (building the hash table in each backend) because
2367 : : * no one process has all the match bits.
2368 : : */
2369 [ + + + + ]: 59482 : if (jointype == JOIN_FULL ||
2370 [ + + ]: 56495 : jointype == JOIN_RIGHT ||
2371 : : jointype == JOIN_RIGHT_ANTI)
2372 : 3244 : cheapest_safe_inner = NULL;
2373 [ + + ]: 56238 : else if (cheapest_total_inner->parallel_safe)
2374 : 56019 : cheapest_safe_inner = cheapest_total_inner;
2375 : : else
2376 : : cheapest_safe_inner =
2377 : 219 : get_cheapest_parallel_safe_total_inner(innerrel->pathlist);
2378 : :
2379 [ + + ]: 59482 : if (cheapest_safe_inner != NULL)
2380 : 56210 : try_partial_hashjoin_path(root, joinrel,
2381 : : cheapest_partial_outer,
2382 : : cheapest_safe_inner,
2383 : : hashclauses, jointype, extra,
2384 : : false /* parallel_hash */ );
2385 : : }
2386 : : }
2387 : : }
2388 : :
2389 : : /*
2390 : : * select_mergejoin_clauses
2391 : : * Select mergejoin clauses that are usable for a particular join.
2392 : : * Returns a list of RestrictInfo nodes for those clauses.
2393 : : *
2394 : : * *mergejoin_allowed is normally set to true, but it is set to false if
2395 : : * this is a right-semi join, or this is a right/right-anti/full join and
2396 : : * there are nonmergejoinable join clauses. The executor's mergejoin
2397 : : * machinery cannot handle such cases, so we have to avoid generating a
2398 : : * mergejoin plan. (Note that this flag does NOT consider whether there are
2399 : : * actually any mergejoinable clauses. This is correct because in some
2400 : : * cases we need to build a clauseless mergejoin. Simply returning NIL is
2401 : : * therefore not enough to distinguish safe from unsafe cases.)
2402 : : *
2403 : : * We also mark each selected RestrictInfo to show which side is currently
2404 : : * being considered as outer. These are transient markings that are only
2405 : : * good for the duration of the current add_paths_to_joinrel() call!
2406 : : *
2407 : : * We examine each restrictinfo clause known for the join to see
2408 : : * if it is mergejoinable and involves vars from the two sub-relations
2409 : : * currently of interest.
2410 : : */
2411 : : static List *
2412 : 543246 : select_mergejoin_clauses(PlannerInfo *root,
2413 : : RelOptInfo *joinrel,
2414 : : RelOptInfo *outerrel,
2415 : : RelOptInfo *innerrel,
2416 : : List *restrictlist,
2417 : : JoinType jointype,
2418 : : bool *mergejoin_allowed)
2419 : : {
2420 : 543246 : List *result_list = NIL;
2421 : 543246 : bool isouterjoin = IS_OUTER_JOIN(jointype);
2422 : 543246 : bool have_nonmergeable_joinclause = false;
2423 : : ListCell *l;
2424 : :
2425 : : /*
2426 : : * For now we do not support RIGHT_SEMI join in mergejoin: the benefit of
2427 : : * swapping inputs tends to be small here.
2428 : : */
2429 [ + + ]: 543246 : if (jointype == JOIN_RIGHT_SEMI)
2430 : : {
2431 : 4879 : *mergejoin_allowed = false;
2432 : 4879 : return NIL;
2433 : : }
2434 : :
2435 [ + + + + : 1136704 : foreach(l, restrictlist)
+ + ]
2436 : : {
2437 : 598337 : RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(l);
2438 : :
2439 : : /*
2440 : : * If processing an outer join, only use its own join clauses in the
2441 : : * merge. For inner joins we can use pushed-down clauses too. (Note:
2442 : : * we don't set have_nonmergeable_joinclause here because pushed-down
2443 : : * clauses will become otherquals not joinquals.)
2444 : : */
2445 [ + + + + : 598337 : if (isouterjoin && RINFO_IS_PUSHED_DOWN(restrictinfo, joinrel->relids))
- + ]
2446 : 10473 : continue;
2447 : :
2448 : : /* Check that clause is a mergeable operator clause */
2449 [ + + ]: 587864 : if (!restrictinfo->can_join ||
2450 [ + + ]: 538701 : restrictinfo->mergeopfamilies == NIL)
2451 : : {
2452 : : /*
2453 : : * The executor can handle extra joinquals that are constants, but
2454 : : * not anything else, when doing right/right-anti/full merge join.
2455 : : * (The reason to support constants is so we can do FULL JOIN ON
2456 : : * FALSE.)
2457 : : */
2458 [ + - + + ]: 58371 : if (!restrictinfo->clause || !IsA(restrictinfo->clause, Const))
2459 : 50759 : have_nonmergeable_joinclause = true;
2460 : 58371 : continue; /* not mergejoinable */
2461 : : }
2462 : :
2463 : : /*
2464 : : * Check if clause has the form "outer op inner" or "inner op outer".
2465 : : */
2466 [ + + ]: 529493 : if (!clause_sides_match_join(restrictinfo, outerrel->relids,
2467 : : innerrel->relids))
2468 : : {
2469 : 672 : have_nonmergeable_joinclause = true;
2470 : 672 : continue; /* no good for these input relations */
2471 : : }
2472 : :
2473 : : /*
2474 : : * If clause has the form "inner op outer", check if its operator has
2475 : : * valid commutator. This is necessary because mergejoin clauses in
2476 : : * this form will get commuted in createplan.c to put the outer var on
2477 : : * the left (see get_switched_clauses). This probably shouldn't ever
2478 : : * fail, since mergejoinable operators ought to have commutators, but
2479 : : * be paranoid.
2480 : : *
2481 : : * The clause being mergejoinable indicates that it's an OpExpr.
2482 : : */
2483 [ + + + + ]: 791148 : if (!restrictinfo->outer_is_left &&
2484 : 262327 : !OidIsValid(get_commutator(castNode(OpExpr, restrictinfo->clause)->opno)))
2485 : : {
2486 : 26 : have_nonmergeable_joinclause = true;
2487 : 26 : continue;
2488 : : }
2489 : :
2490 : : /*
2491 : : * Insist that each side have a non-redundant eclass. This
2492 : : * restriction is needed because various bits of the planner expect
2493 : : * that each clause in a merge be associable with some pathkey in a
2494 : : * canonical pathkey list, but redundant eclasses can't appear in
2495 : : * canonical sort orderings. (XXX it might be worth relaxing this,
2496 : : * but not enough time to address it for 8.3.)
2497 : : */
2498 : 528795 : update_mergeclause_eclasses(root, restrictinfo);
2499 : :
2500 [ + + ]: 528795 : if (EC_MUST_BE_REDUNDANT(restrictinfo->left_ec) ||
2501 [ + + ]: 528763 : EC_MUST_BE_REDUNDANT(restrictinfo->right_ec))
2502 : : {
2503 : 84 : have_nonmergeable_joinclause = true;
2504 : 84 : continue; /* can't handle redundant eclasses */
2505 : : }
2506 : :
2507 : 528711 : result_list = lappend(result_list, restrictinfo);
2508 : : }
2509 : :
2510 : : /*
2511 : : * Report whether mergejoin is allowed (see comment at top of function).
2512 : : */
2513 [ + + ]: 538367 : switch (jointype)
2514 : : {
2515 : 69407 : case JOIN_RIGHT:
2516 : : case JOIN_RIGHT_ANTI:
2517 : : case JOIN_FULL:
2518 : 69407 : *mergejoin_allowed = !have_nonmergeable_joinclause;
2519 : 69407 : break;
2520 : 468960 : default:
2521 : 468960 : *mergejoin_allowed = true;
2522 : 468960 : break;
2523 : : }
2524 : :
2525 : 538367 : return result_list;
2526 : : }
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