Age Owner Branch data TLA Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * joinrels.c
4 : : * Routines to determine which relations should be joined
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/joinrels.c
12 : : *
13 : : *-------------------------------------------------------------------------
14 : : */
15 : : #include "postgres.h"
16 : :
17 : : #include "miscadmin.h"
18 : : #include "optimizer/appendinfo.h"
19 : : #include "optimizer/cost.h"
20 : : #include "optimizer/joininfo.h"
21 : : #include "optimizer/pathnode.h"
22 : : #include "optimizer/paths.h"
23 : : #include "optimizer/planner.h"
24 : : #include "partitioning/partbounds.h"
25 : : #include "utils/memutils.h"
26 : :
27 : :
28 : : static void make_rels_by_clause_joins(PlannerInfo *root,
29 : : RelOptInfo *old_rel,
30 : : List *other_rels,
31 : : int first_rel_idx);
32 : : static void make_rels_by_clauseless_joins(PlannerInfo *root,
33 : : RelOptInfo *old_rel,
34 : : List *other_rels);
35 : : static bool has_join_restriction(PlannerInfo *root, RelOptInfo *rel);
36 : : static bool has_legal_joinclause(PlannerInfo *root, RelOptInfo *rel);
37 : : static bool restriction_is_constant_false(List *restrictlist,
38 : : RelOptInfo *joinrel,
39 : : bool only_pushed_down);
40 : : static void make_grouped_join_rel(PlannerInfo *root, RelOptInfo *rel1,
41 : : RelOptInfo *rel2, RelOptInfo *joinrel,
42 : : SpecialJoinInfo *sjinfo, List *restrictlist);
43 : : static void populate_joinrel_with_paths(PlannerInfo *root, RelOptInfo *rel1,
44 : : RelOptInfo *rel2, RelOptInfo *joinrel,
45 : : SpecialJoinInfo *sjinfo, List *restrictlist);
46 : : static void try_partitionwise_join(PlannerInfo *root, RelOptInfo *rel1,
47 : : RelOptInfo *rel2, RelOptInfo *joinrel,
48 : : SpecialJoinInfo *parent_sjinfo,
49 : : List *parent_restrictlist);
50 : : static SpecialJoinInfo *build_child_join_sjinfo(PlannerInfo *root,
51 : : SpecialJoinInfo *parent_sjinfo,
52 : : Relids left_relids, Relids right_relids);
53 : : static void free_child_join_sjinfo(SpecialJoinInfo *child_sjinfo,
54 : : SpecialJoinInfo *parent_sjinfo);
55 : : static void compute_partition_bounds(PlannerInfo *root, RelOptInfo *rel1,
56 : : RelOptInfo *rel2, RelOptInfo *joinrel,
57 : : SpecialJoinInfo *parent_sjinfo,
58 : : List **parts1, List **parts2);
59 : : static void get_matching_part_pairs(PlannerInfo *root, RelOptInfo *joinrel,
60 : : RelOptInfo *rel1, RelOptInfo *rel2,
61 : : List **parts1, List **parts2);
62 : :
63 : :
64 : : /*
65 : : * join_search_one_level
66 : : * Consider ways to produce join relations containing exactly 'level'
67 : : * jointree items. (This is one step of the dynamic-programming method
68 : : * embodied in standard_join_search.) Join rel nodes for each feasible
69 : : * combination of lower-level rels are created and returned in a list.
70 : : * Implementation paths are created for each such joinrel, too.
71 : : *
72 : : * level: level of rels we want to make this time
73 : : * root->join_rel_level[j], 1 <= j < level, is a list of rels containing j items
74 : : *
75 : : * The result is returned in root->join_rel_level[level].
76 : : */
77 : : void
5951 tgl@sss.pgh.pa.us 78 :CBC 80031 : join_search_one_level(PlannerInfo *root, int level)
79 : : {
80 : 80031 : List **joinrels = root->join_rel_level;
81 : : ListCell *r;
82 : : int k;
83 : :
84 [ - + ]: 80031 : Assert(joinrels[level] == NIL);
85 : :
86 : : /* Set join_cur_level so that new joinrels are added to proper list */
87 : 80031 : root->join_cur_level = level;
88 : :
89 : : /*
90 : : * First, consider left-sided and right-sided plans, in which rels of
91 : : * exactly level-1 member relations are joined against initial relations.
92 : : * We prefer to join using join clauses, but if we find a rel of level-1
93 : : * members that has no join clauses, we will generate Cartesian-product
94 : : * joins against all initial rels not already contained in it.
95 : : */
9124 bruce@momjian.us 96 [ + + + + : 286598 : foreach(r, joinrels[level - 1])
+ + ]
97 : : {
9887 98 : 206567 : RelOptInfo *old_rel = (RelOptInfo *) lfirst(r);
99 : :
6967 tgl@sss.pgh.pa.us 100 [ + + + + : 223530 : if (old_rel->joininfo != NIL || old_rel->has_eclass_joins ||
+ + ]
101 : 16963 : has_join_restriction(root, old_rel))
9533 102 : 200751 : {
103 : : int first_rel;
104 : :
105 : : /*
106 : : * There are join clauses or join order restrictions relevant to
107 : : * this rel, so consider joins between this rel and (only) those
108 : : * initial rels it is linked to by a clause or restriction.
109 : : *
110 : : * At level 2 this condition is symmetric, so there is no need to
111 : : * look at initial rels before this one in the list; we already
112 : : * considered such joins when we were at the earlier rel. (The
113 : : * mirror-image joins are handled automatically by make_join_rel.)
114 : : * In later passes (level > 2), we join rels of the previous level
115 : : * to each initial rel they don't already include but have a join
116 : : * clause or restriction with.
117 : : */
5077 118 [ + + ]: 200751 : if (level == 2) /* consider remaining initial rels */
952 drowley@postgresql.o 119 : 132852 : first_rel = foreach_current_index(r) + 1;
120 : : else
121 : 67899 : first_rel = 0;
122 : :
123 : 200751 : make_rels_by_clause_joins(root, old_rel, joinrels[1], first_rel);
124 : : }
125 : : else
126 : : {
127 : : /*
128 : : * Oops, we have a relation that is not joined to any other
129 : : * relation, either directly or by join-order restrictions.
130 : : * Cartesian product time.
131 : : *
132 : : * We consider a cartesian product with each not-already-included
133 : : * initial rel, whether it has other join clauses or not. At
134 : : * level 2, if there are two or more clauseless initial rels, we
135 : : * will redundantly consider joining them in both directions; but
136 : : * such cases aren't common enough to justify adding complexity to
137 : : * avoid the duplicated effort.
138 : : */
5951 tgl@sss.pgh.pa.us 139 : 5816 : make_rels_by_clauseless_joins(root,
140 : : old_rel,
2435 141 : 5816 : joinrels[1]);
142 : : }
143 : : }
144 : :
145 : : /*
146 : : * Now, consider "bushy plans" in which relations of k initial rels are
147 : : * joined to relations of level-k initial rels, for 2 <= k <= level-2.
148 : : *
149 : : * We only consider bushy-plan joins for pairs of rels where there is a
150 : : * suitable join clause (or join order restriction), in order to avoid
151 : : * unreasonable growth of planning time.
152 : : */
9124 bruce@momjian.us 153 : 80031 : for (k = 2;; k++)
9791 154 : 8358 : {
9315 tgl@sss.pgh.pa.us 155 : 88389 : int other_level = level - k;
156 : :
157 : : /*
158 : : * Since make_join_rel(x, y) handles both x,y and y,x cases, we only
159 : : * need to go as far as the halfway point.
160 : : */
161 [ + + ]: 88389 : if (k > other_level)
9533 162 : 80031 : break;
163 : :
9315 164 [ + - + + : 44229 : foreach(r, joinrels[k])
+ + ]
165 : : {
166 : 35871 : RelOptInfo *old_rel = (RelOptInfo *) lfirst(r);
167 : : int first_rel;
168 : : ListCell *r2;
169 : :
170 : : /*
171 : : * We can ignore relations without join clauses here, unless they
172 : : * participate in join-order restrictions --- then we might have
173 : : * to force a bushy join plan.
174 : : */
6994 175 [ + + + + ]: 35871 : if (old_rel->joininfo == NIL && !old_rel->has_eclass_joins &&
6967 176 [ + + ]: 219 : !has_join_restriction(root, old_rel))
7033 177 : 150 : continue;
178 : :
952 drowley@postgresql.o 179 [ + + ]: 35721 : if (k == other_level) /* only consider remaining rels */
180 : 24015 : first_rel = foreach_current_index(r) + 1;
181 : : else
182 : 11706 : first_rel = 0;
183 : :
184 [ + - + + : 159331 : for_each_from(r2, joinrels[other_level], first_rel)
+ + ]
185 : : {
9315 tgl@sss.pgh.pa.us 186 : 123610 : RelOptInfo *new_rel = (RelOptInfo *) lfirst(r2);
187 : :
8436 188 [ + + ]: 123610 : if (!bms_overlap(old_rel->relids, new_rel->relids))
189 : : {
190 : : /*
191 : : * OK, we can build a rel of the right level from this
192 : : * pair of rels. Do so if there is at least one relevant
193 : : * join clause or join order restriction.
194 : : */
6967 195 [ + + + + ]: 13848 : if (have_relevant_joinclause(root, old_rel, new_rel) ||
196 : 595 : have_join_order_restriction(root, old_rel, new_rel))
197 : : {
5951 198 : 12691 : (void) make_join_rel(root, old_rel, new_rel);
199 : : }
200 : : }
201 : : }
202 : : }
203 : : }
204 : :
205 : : /*----------
206 : : * Last-ditch effort: if we failed to find any usable joins so far, force
207 : : * a set of cartesian-product joins to be generated. This handles the
208 : : * special case where all the available rels have join clauses but we
209 : : * cannot use any of those clauses yet. This can only happen when we are
210 : : * considering a join sub-problem (a sub-joinlist) and all the rels in the
211 : : * sub-problem have only join clauses with rels outside the sub-problem.
212 : : * An example is
213 : : *
214 : : * SELECT ... FROM a INNER JOIN b ON TRUE, c, d, ...
215 : : * WHERE a.w = c.x and b.y = d.z;
216 : : *
217 : : * If the "a INNER JOIN b" sub-problem does not get flattened into the
218 : : * upper level, we must be willing to make a cartesian join of a and b;
219 : : * but the code above will not have done so, because it thought that both
220 : : * a and b have joinclauses. We consider only left-sided and right-sided
221 : : * cartesian joins in this case (no bushy).
222 : : *----------
223 : : */
4960 224 [ + + ]: 80031 : if (joinrels[level] == NIL)
225 : : {
226 : : /*
227 : : * This loop is just like the first one, except we always call
228 : : * make_rels_by_clauseless_joins().
229 : : */
230 [ + - + + : 27 : foreach(r, joinrels[level - 1])
+ + ]
231 : : {
232 : 18 : RelOptInfo *old_rel = (RelOptInfo *) lfirst(r);
233 : :
234 : 18 : make_rels_by_clauseless_joins(root,
235 : : old_rel,
2435 236 : 18 : joinrels[1]);
237 : : }
238 : :
239 : : /*----------
240 : : * When special joins are involved, there may be no legal way
241 : : * to make an N-way join for some values of N. For example consider
242 : : *
243 : : * SELECT ... FROM t1 WHERE
244 : : * x IN (SELECT ... FROM t2,t3 WHERE ...) AND
245 : : * y IN (SELECT ... FROM t4,t5 WHERE ...)
246 : : *
247 : : * We will flatten this query to a 5-way join problem, but there are
248 : : * no 4-way joins that join_is_legal() will consider legal. We have
249 : : * to accept failure at level 4 and go on to discover a workable
250 : : * bushy plan at level 5.
251 : : *
252 : : * However, if there are no special joins and no lateral references
253 : : * then join_is_legal() should never fail, and so the following sanity
254 : : * check is useful.
255 : : *----------
256 : : */
4949 257 [ + + ]: 9 : if (joinrels[level] == NIL &&
258 [ - + ]: 3 : root->join_info_list == NIL &&
3747 tgl@sss.pgh.pa.us 259 [ # # ]:UBC 0 : !root->hasLateralRTEs)
4960 260 [ # # ]: 0 : elog(ERROR, "failed to build any %d-way joins", level);
261 : : }
10841 scrappy@hub.org 262 :CBC 80031 : }
263 : :
264 : : /*
265 : : * make_rels_by_clause_joins
266 : : * Build joins between the given relation 'old_rel' and other relations
267 : : * that participate in join clauses that 'old_rel' also participates in
268 : : * (or participate in join-order restrictions with it).
269 : : * The join rels are returned in root->join_rel_level[join_cur_level].
270 : : *
271 : : * Note: at levels above 2 we will generate the same joined relation in
272 : : * multiple ways --- for example (a join b) join c is the same RelOptInfo as
273 : : * (b join c) join a, though the second case will add a different set of Paths
274 : : * to it. This is the reason for using the join_rel_level mechanism, which
275 : : * automatically ensures that each new joinrel is only added to the list once.
276 : : *
277 : : * 'old_rel' is the relation entry for the relation to be joined
278 : : * 'other_rels': a list containing the other rels to be considered for joining
279 : : * 'first_rel_idx': the first rel to be considered in 'other_rels'
280 : : *
281 : : * Currently, this is only used with initial rels in other_rels, but it
282 : : * will work for joining to joinrels too.
283 : : */
284 : : static void
7588 tgl@sss.pgh.pa.us 285 : 200751 : make_rels_by_clause_joins(PlannerInfo *root,
286 : : RelOptInfo *old_rel,
287 : : List *other_rels,
288 : : int first_rel_idx)
289 : : {
290 : : ListCell *l;
291 : :
952 drowley@postgresql.o 292 [ + - + + : 605442 : for_each_from(l, other_rels, first_rel_idx)
+ + ]
293 : : {
7584 tgl@sss.pgh.pa.us 294 : 404691 : RelOptInfo *other_rel = (RelOptInfo *) lfirst(l);
295 : :
296 [ + + + + ]: 632590 : if (!bms_overlap(old_rel->relids, other_rel->relids) &&
6967 297 [ + + ]: 276950 : (have_relevant_joinclause(root, old_rel, other_rel) ||
298 : 49051 : have_join_order_restriction(root, old_rel, other_rel)))
299 : : {
5951 300 : 187163 : (void) make_join_rel(root, old_rel, other_rel);
301 : : }
302 : : }
10841 scrappy@hub.org 303 : 200751 : }
304 : :
305 : : /*
306 : : * make_rels_by_clauseless_joins
307 : : * Given a relation 'old_rel' and a list of other relations
308 : : * 'other_rels', create a join relation between 'old_rel' and each
309 : : * member of 'other_rels' that isn't already included in 'old_rel'.
310 : : * The join rels are returned in root->join_rel_level[join_cur_level].
311 : : *
312 : : * 'old_rel' is the relation entry for the relation to be joined
313 : : * 'other_rels': a list containing the other rels to be considered for joining
314 : : *
315 : : * Currently, this is only used with initial rels in other_rels, but it would
316 : : * work for joining to joinrels too.
317 : : */
318 : : static void
7588 tgl@sss.pgh.pa.us 319 : 5834 : make_rels_by_clauseless_joins(PlannerInfo *root,
320 : : RelOptInfo *old_rel,
321 : : List *other_rels)
322 : : {
323 : : ListCell *l;
324 : :
2435 325 [ + - + + : 19275 : foreach(l, other_rels)
+ + ]
326 : : {
5951 327 : 13441 : RelOptInfo *other_rel = (RelOptInfo *) lfirst(l);
328 : :
8436 329 [ + + ]: 13441 : if (!bms_overlap(other_rel->relids, old_rel->relids))
330 : : {
5951 331 : 6352 : (void) make_join_rel(root, old_rel, other_rel);
332 : : }
333 : : }
10841 scrappy@hub.org 334 : 5834 : }
335 : :
336 : :
337 : : /*
338 : : * join_is_legal
339 : : * Determine whether a proposed join is legal given the query's
340 : : * join order constraints; and if it is, determine the join type.
341 : : *
342 : : * Caller must supply not only the two rels, but the union of their relids.
343 : : * (We could simplify the API by computing joinrelids locally, but this
344 : : * would be redundant work in the normal path through make_join_rel.
345 : : * Note that this value does NOT include the RT index of any outer join that
346 : : * might need to be performed here, so it's not the canonical identifier
347 : : * of the join relation.)
348 : : *
349 : : * On success, *sjinfo_p is set to NULL if this is to be a plain inner join,
350 : : * else it's set to point to the associated SpecialJoinInfo node. Also,
351 : : * *reversed_p is set true if the given relations need to be swapped to
352 : : * match the SpecialJoinInfo node.
353 : : */
354 : : static bool
6715 tgl@sss.pgh.pa.us 355 : 210628 : join_is_legal(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2,
356 : : Relids joinrelids,
357 : : SpecialJoinInfo **sjinfo_p, bool *reversed_p)
358 : : {
359 : : SpecialJoinInfo *match_sjinfo;
360 : : bool reversed;
361 : : bool unique_ified;
362 : : bool must_be_leftjoin;
363 : : ListCell *l;
364 : :
365 : : /*
366 : : * Ensure output params are set on failure return. This is just to
367 : : * suppress uninitialized-variable warnings from overly anal compilers.
368 : : */
6422 369 : 210628 : *sjinfo_p = NULL;
370 : 210628 : *reversed_p = false;
371 : :
372 : : /*
373 : : * If we have any special joins, the proposed join might be illegal; and
374 : : * in any case we have to determine its join type. Scan the join info
375 : : * list for matches and conflicts.
376 : : */
377 : 210628 : match_sjinfo = NULL;
378 : 210628 : reversed = false;
6083 379 : 210628 : unique_ified = false;
3874 380 : 210628 : must_be_leftjoin = false;
381 : :
6422 382 [ + + + + : 426828 : foreach(l, root->join_info_list)
+ + ]
383 : : {
384 : 220964 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
385 : :
386 : : /*
387 : : * This special join is not relevant unless its RHS overlaps the
388 : : * proposed join. (Check this first as a fast path for dismissing
389 : : * most irrelevant SJs quickly.)
390 : : */
391 [ + + ]: 220964 : if (!bms_overlap(sjinfo->min_righthand, joinrelids))
7390 392 : 75083 : continue;
393 : :
394 : : /*
395 : : * Also, not relevant if proposed join is fully contained within RHS
396 : : * (ie, we're still building up the RHS).
397 : : */
6422 398 [ + + ]: 145881 : if (bms_is_subset(joinrelids, sjinfo->min_righthand))
7390 399 : 2694 : continue;
400 : :
401 : : /*
402 : : * Also, not relevant if SJ is already done within either input.
403 : : */
6422 404 [ + + + + ]: 269122 : if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) &&
405 : 125935 : bms_is_subset(sjinfo->min_righthand, rel1->relids))
7390 406 : 62727 : continue;
6422 407 [ + + + + ]: 92157 : if (bms_is_subset(sjinfo->min_lefthand, rel2->relids) &&
408 : 11697 : bms_is_subset(sjinfo->min_righthand, rel2->relids))
7390 409 : 6611 : continue;
410 : :
411 : : /*
412 : : * If it's a semijoin and we already joined the RHS to any other rels
413 : : * within either input, then we must have unique-ified the RHS at that
414 : : * point (see below). Therefore the semijoin is no longer relevant in
415 : : * this join path.
416 : : */
6079 417 [ + + ]: 73849 : if (sjinfo->jointype == JOIN_SEMI)
418 : : {
419 [ + + ]: 5584 : if (bms_is_subset(sjinfo->syn_righthand, rel1->relids) &&
420 [ + + ]: 788 : !bms_equal(sjinfo->syn_righthand, rel1->relids))
421 : 345 : continue;
422 [ + + ]: 5239 : if (bms_is_subset(sjinfo->syn_righthand, rel2->relids) &&
423 [ + + ]: 3713 : !bms_equal(sjinfo->syn_righthand, rel2->relids))
424 : 107 : continue;
425 : : }
426 : :
427 : : /*
428 : : * If one input contains min_lefthand and the other contains
429 : : * min_righthand, then we can perform the SJ at this join.
430 : : *
431 : : * Reject if we get matches to more than one SJ; that implies we're
432 : : * considering something that's not really valid.
433 : : */
6422 434 [ + + + + ]: 136529 : if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) &&
435 : 63132 : bms_is_subset(sjinfo->min_righthand, rel2->relids))
436 : : {
437 [ - + ]: 59753 : if (match_sjinfo)
6695 bruce@momjian.us 438 : 4764 : return false; /* invalid join path */
6422 tgl@sss.pgh.pa.us 439 : 59753 : match_sjinfo = sjinfo;
440 : 59753 : reversed = false;
441 : : }
442 [ + + + + ]: 18561 : else if (bms_is_subset(sjinfo->min_lefthand, rel2->relids) &&
443 : 4917 : bms_is_subset(sjinfo->min_righthand, rel1->relids))
444 : : {
445 [ - + ]: 4302 : if (match_sjinfo)
6695 bruce@momjian.us 446 :UBC 0 : return false; /* invalid join path */
6422 tgl@sss.pgh.pa.us 447 :CBC 4302 : match_sjinfo = sjinfo;
448 : 4302 : reversed = true;
449 : : }
6322 450 [ + + + + ]: 10847 : else if (sjinfo->jointype == JOIN_SEMI &&
6316 451 [ + + ]: 1809 : bms_equal(sjinfo->syn_righthand, rel2->relids) &&
208 rguo@postgresql.org 452 :GNC 304 : create_unique_paths(root, rel2, sjinfo) != NULL)
453 : : {
454 : : /*----------
455 : : * For a semijoin, we can join the RHS to anything else by
456 : : * unique-ifying the RHS (if the RHS can be unique-ified).
457 : : * We will only get here if we have the full RHS but less
458 : : * than min_lefthand on the LHS.
459 : : *
460 : : * The reason to consider such a join path is exemplified by
461 : : * SELECT ... FROM a,b WHERE (a.x,b.y) IN (SELECT c1,c2 FROM c)
462 : : * If we insist on doing this as a semijoin we will first have
463 : : * to form the cartesian product of A*B. But if we unique-ify
464 : : * C then the semijoin becomes a plain innerjoin and we can join
465 : : * in any order, eg C to A and then to B. When C is much smaller
466 : : * than A and B this can be a huge win. So we allow C to be
467 : : * joined to just A or just B here, and then make_join_rel has
468 : : * to handle the case properly.
469 : : *
470 : : * Note that actually we'll allow unique-ified C to be joined to
471 : : * some other relation D here, too. That is legal, if usually not
472 : : * very sane, and this routine is only concerned with legality not
473 : : * with whether the join is good strategy.
474 : : *----------
475 : : */
6322 tgl@sss.pgh.pa.us 476 [ + + ]:CBC 196 : if (match_sjinfo)
477 : 3 : return false; /* invalid join path */
478 : 193 : match_sjinfo = sjinfo;
479 : 193 : reversed = false;
6083 480 : 193 : unique_ified = true;
481 : : }
6322 482 [ + + + + ]: 10455 : else if (sjinfo->jointype == JOIN_SEMI &&
6316 483 [ + + ]: 1427 : bms_equal(sjinfo->syn_righthand, rel1->relids) &&
208 rguo@postgresql.org 484 :GNC 118 : create_unique_paths(root, rel1, sjinfo) != NULL)
485 : : {
486 : : /* Reversed semijoin case */
6322 tgl@sss.pgh.pa.us 487 [ - + ]:CBC 52 : if (match_sjinfo)
6322 tgl@sss.pgh.pa.us 488 :UBC 0 : return false; /* invalid join path */
6322 tgl@sss.pgh.pa.us 489 :CBC 52 : match_sjinfo = sjinfo;
490 : 52 : reversed = true;
6083 491 : 52 : unique_ified = true;
492 : : }
493 : : else
494 : : {
495 : : /*
496 : : * Otherwise, the proposed join overlaps the RHS but isn't a valid
497 : : * implementation of this SJ. But don't panic quite yet: the RHS
498 : : * violation might have occurred previously, in one or both input
499 : : * relations, in which case we must have previously decided that
500 : : * it was OK to commute some other SJ with this one. If we need
501 : : * to perform this join to finish building up the RHS, rejecting
502 : : * it could lead to not finding any plan at all. (This can occur
503 : : * because of the heuristics elsewhere in this file that postpone
504 : : * clauseless joins: we might not consider doing a clauseless join
505 : : * within the RHS until after we've performed other, validly
506 : : * commutable SJs with one or both sides of the clauseless join.)
507 : : * This consideration boils down to the rule that if both inputs
508 : : * overlap the RHS, we can allow the join --- they are either
509 : : * fully within the RHS, or represent previously-allowed joins to
510 : : * rels outside it.
511 : : */
3868 512 [ + + + + ]: 13363 : if (bms_overlap(rel1->relids, sjinfo->min_righthand) &&
513 : 4269 : bms_overlap(rel2->relids, sjinfo->min_righthand))
514 : 87 : continue; /* assume valid previous violation of RHS */
515 : :
516 : : /*
517 : : * The proposed join could still be legal, but only if we're
518 : : * allowed to associate it into the RHS of this SJ. That means
519 : : * this SJ must be a LEFT join (not SEMI or ANTI, and certainly
520 : : * not FULL) and the proposed join must not overlap the LHS.
521 : : */
3874 522 [ + + + + ]: 16655 : if (sjinfo->jointype != JOIN_LEFT ||
3875 523 : 7648 : bms_overlap(joinrelids, sjinfo->min_lefthand))
524 : 4761 : return false; /* invalid join path */
525 : :
526 : : /*
527 : : * To be valid, the proposed join must be a LEFT join; otherwise
528 : : * it can't associate into this SJ's RHS. But we may not yet have
529 : : * found the SpecialJoinInfo matching the proposed join, so we
530 : : * can't test that yet. Remember the requirement for later.
531 : : */
3874 532 : 4246 : must_be_leftjoin = true;
533 : : }
534 : : }
535 : :
536 : : /*
537 : : * Fail if violated any SJ's RHS and didn't match to a LEFT SJ: the
538 : : * proposed join can't associate into an SJ's RHS.
539 : : *
540 : : * Also, fail if the proposed join's predicate isn't strict; we're
541 : : * essentially checking to see if we can apply outer-join identity 3, and
542 : : * that's a requirement. (This check may be redundant with checks in
543 : : * make_outerjoininfo, but I'm not quite sure, and it's cheap to test.)
544 : : */
545 [ + + + + ]: 205864 : if (must_be_leftjoin &&
546 : 2695 : (match_sjinfo == NULL ||
547 [ + - ]: 2695 : match_sjinfo->jointype != JOIN_LEFT ||
548 [ - + ]: 2695 : !match_sjinfo->lhs_strict))
6715 549 : 793 : return false; /* invalid join path */
550 : :
551 : : /*
552 : : * We also have to check for constraints imposed by LATERAL references.
553 : : */
3747 554 [ + + ]: 205071 : if (root->hasLateralRTEs)
555 : : {
556 : : bool lateral_fwd;
557 : : bool lateral_rev;
558 : : Relids join_lateral_rels;
559 : :
560 : : /*
561 : : * The proposed rels could each contain lateral references to the
562 : : * other, in which case the join is impossible. If there are lateral
563 : : * references in just one direction, then the join has to be done with
564 : : * a nestloop with the lateral referencer on the inside. If the join
565 : : * matches an SJ that cannot be implemented by such a nestloop, the
566 : : * join is impossible.
567 : : *
568 : : * Also, if the lateral reference is only indirect, we should reject
569 : : * the join; whatever rel(s) the reference chain goes through must be
570 : : * joined to first.
571 : : */
572 : 21769 : lateral_fwd = bms_overlap(rel1->relids, rel2->lateral_relids);
573 : 21769 : lateral_rev = bms_overlap(rel2->relids, rel1->lateral_relids);
574 [ + + + + ]: 21769 : if (lateral_fwd && lateral_rev)
575 : 15 : return false; /* have lateral refs in both directions */
576 [ + + ]: 21754 : if (lateral_fwd)
577 : : {
578 : : /* has to be implemented as nestloop with rel1 on left */
4949 579 [ + + + - ]: 8434 : if (match_sjinfo &&
3880 580 [ + + ]: 1012 : (reversed ||
581 : 1003 : unique_ified ||
582 [ - + ]: 1003 : match_sjinfo->jointype == JOIN_FULL))
4949 583 : 9 : return false; /* not implementable as nestloop */
584 : : /* check there is a direct reference from rel2 to rel1 */
3747 585 [ + + ]: 8425 : if (!bms_overlap(rel1->relids, rel2->direct_lateral_relids))
586 : 21 : return false; /* only indirect refs, so reject */
587 : : }
588 [ + + ]: 13320 : else if (lateral_rev)
589 : : {
590 : : /* has to be implemented as nestloop with rel2 on left */
4949 591 [ + + ]: 2174 : if (match_sjinfo &&
3880 592 [ + - + - ]: 39 : (!reversed ||
593 : 39 : unique_ified ||
594 [ - + ]: 39 : match_sjinfo->jointype == JOIN_FULL))
4949 tgl@sss.pgh.pa.us 595 :UBC 0 : return false; /* not implementable as nestloop */
596 : : /* check there is a direct reference from rel1 to rel2 */
3747 tgl@sss.pgh.pa.us 597 [ - + ]:CBC 2174 : if (!bms_overlap(rel2->relids, rel1->direct_lateral_relids))
3747 tgl@sss.pgh.pa.us 598 :UBC 0 : return false; /* only indirect refs, so reject */
599 : : }
600 : :
601 : : /*
602 : : * LATERAL references could also cause problems later on if we accept
603 : : * this join: if the join's minimum parameterization includes any rels
604 : : * that would have to be on the inside of an outer join with this join
605 : : * rel, then it's never going to be possible to build the complete
606 : : * query using this join. We should reject this join not only because
607 : : * it'll save work, but because if we don't, the clauseless-join
608 : : * heuristics might think that legality of this join means that some
609 : : * other join rel need not be formed, and that could lead to failure
610 : : * to find any plan at all. We have to consider not only rels that
611 : : * are directly on the inner side of an OJ with the joinrel, but also
612 : : * ones that are indirectly so, so search to find all such rels.
613 : : */
3747 tgl@sss.pgh.pa.us 614 :CBC 21724 : join_lateral_rels = min_join_parameterization(root, joinrelids,
615 : : rel1, rel2);
616 [ + + ]: 21724 : if (join_lateral_rels)
617 : : {
618 : 3347 : Relids join_plus_rhs = bms_copy(joinrelids);
619 : : bool more;
620 : :
621 : : do
622 : : {
623 : 3657 : more = false;
624 [ + + + + : 4844 : foreach(l, root->join_info_list)
+ + ]
625 : : {
626 : 1187 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
627 : :
628 : : /* ignore full joins --- their ordering is predetermined */
2533 629 [ + + ]: 1187 : if (sjinfo->jointype == JOIN_FULL)
630 : 9 : continue;
631 : :
3747 632 [ + + ]: 1178 : if (bms_overlap(sjinfo->min_lefthand, join_plus_rhs) &&
633 [ + + ]: 1025 : !bms_is_subset(sjinfo->min_righthand, join_plus_rhs))
634 : : {
635 : 385 : join_plus_rhs = bms_add_members(join_plus_rhs,
3189 636 : 385 : sjinfo->min_righthand);
3747 637 : 385 : more = true;
638 : : }
639 : : }
640 [ + + ]: 3657 : } while (more);
641 [ + + ]: 3347 : if (bms_overlap(join_plus_rhs, join_lateral_rels))
642 : 268 : return false; /* will not be able to join to some RHS rel */
643 : : }
644 : : }
645 : :
646 : : /* Otherwise, it's a valid join */
6422 647 : 204758 : *sjinfo_p = match_sjinfo;
648 : 204758 : *reversed_p = reversed;
6715 649 : 204758 : return true;
650 : : }
651 : :
652 : : /*
653 : : * init_dummy_sjinfo
654 : : * Populate the given SpecialJoinInfo for a plain inner join between the
655 : : * left and right relations specified by left_relids and right_relids
656 : : * respectively.
657 : : *
658 : : * Normally, an inner join does not have a SpecialJoinInfo node associated with
659 : : * it. But some functions involved in join planning require one containing at
660 : : * least the information of which relations are being joined. So we initialize
661 : : * that information here.
662 : : */
663 : : void
720 amitlan@postgresql.o 664 : 722135 : init_dummy_sjinfo(SpecialJoinInfo *sjinfo, Relids left_relids,
665 : : Relids right_relids)
666 : : {
667 : 722135 : sjinfo->type = T_SpecialJoinInfo;
668 : 722135 : sjinfo->min_lefthand = left_relids;
669 : 722135 : sjinfo->min_righthand = right_relids;
670 : 722135 : sjinfo->syn_lefthand = left_relids;
671 : 722135 : sjinfo->syn_righthand = right_relids;
672 : 722135 : sjinfo->jointype = JOIN_INNER;
673 : 722135 : sjinfo->ojrelid = 0;
674 : 722135 : sjinfo->commute_above_l = NULL;
675 : 722135 : sjinfo->commute_above_r = NULL;
676 : 722135 : sjinfo->commute_below_l = NULL;
677 : 722135 : sjinfo->commute_below_r = NULL;
678 : : /* we don't bother trying to make the remaining fields valid */
679 : 722135 : sjinfo->lhs_strict = false;
680 : 722135 : sjinfo->semi_can_btree = false;
681 : 722135 : sjinfo->semi_can_hash = false;
682 : 722135 : sjinfo->semi_operators = NIL;
683 : 722135 : sjinfo->semi_rhs_exprs = NIL;
684 : 722135 : }
685 : :
686 : : /*
687 : : * make_join_rel
688 : : * Find or create a join RelOptInfo that represents the join of
689 : : * the two given rels, and add to it path information for paths
690 : : * created with the two rels as outer and inner rel.
691 : : * (The join rel may already contain paths generated from other
692 : : * pairs of rels that add up to the same set of base rels.)
693 : : *
694 : : * NB: will return NULL if attempted join is not valid. This can happen
695 : : * when working with outer joins, or with IN or EXISTS clauses that have been
696 : : * turned into joins.
697 : : */
698 : : RelOptInfo *
6715 tgl@sss.pgh.pa.us 699 : 210400 : make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
700 : : {
701 : : Relids joinrelids;
702 : : SpecialJoinInfo *sjinfo;
703 : : bool reversed;
1033 704 : 210400 : List *pushed_down_joins = NIL;
705 : : SpecialJoinInfo sjinfo_data;
706 : : RelOptInfo *joinrel;
707 : : List *restrictlist;
708 : :
709 : : /* We should never try to join two overlapping sets of rels. */
6715 710 [ - + ]: 210400 : Assert(!bms_overlap(rel1->relids, rel2->relids));
711 : :
712 : : /* Construct Relids set that identifies the joinrel (without OJ as yet). */
713 : 210400 : joinrelids = bms_union(rel1->relids, rel2->relids);
714 : :
715 : : /* Check validity and determine join type. */
6422 716 [ + + ]: 210400 : if (!join_is_legal(root, rel1, rel2, joinrelids,
717 : : &sjinfo, &reversed))
718 : : {
719 : : /* invalid join path */
6715 720 : 5768 : bms_free(joinrelids);
721 : 5768 : return NULL;
722 : : }
723 : :
724 : : /*
725 : : * Add outer join relid(s) to form the canonical relids. Any added outer
726 : : * joins besides sjinfo itself are appended to pushed_down_joins.
727 : : */
1033 728 : 204632 : joinrelids = add_outer_joins_to_relids(root, joinrelids, sjinfo,
729 : : &pushed_down_joins);
730 : :
731 : : /* Swap rels if needed to match the join info. */
6422 732 [ + + ]: 204632 : if (reversed)
733 : : {
734 : 4342 : RelOptInfo *trel = rel1;
735 : :
736 : 4342 : rel1 = rel2;
737 : 4342 : rel2 = trel;
738 : : }
739 : :
740 : : /*
741 : : * If it's a plain inner join, then we won't have found anything in
742 : : * join_info_list. Make up a SpecialJoinInfo so that selectivity
743 : : * estimation functions will know what's being joined.
744 : : */
745 [ + + ]: 204632 : if (sjinfo == NULL)
746 : : {
747 : 140479 : sjinfo = &sjinfo_data;
720 amitlan@postgresql.o 748 : 140479 : init_dummy_sjinfo(sjinfo, rel1->relids, rel2->relids);
749 : : }
750 : :
751 : : /*
752 : : * Find or build the join RelOptInfo, and compute the restrictlist that
753 : : * goes with this particular joining.
754 : : */
1033 tgl@sss.pgh.pa.us 755 : 204632 : joinrel = build_join_rel(root, joinrelids, rel1, rel2,
756 : : sjinfo, pushed_down_joins,
757 : : &restrictlist);
758 : :
759 : : /*
760 : : * If we've already proven this join is empty, we needn't consider any
761 : : * more paths for it.
762 : : */
6565 763 [ + + ]: 204632 : if (is_dummy_rel(joinrel))
764 : : {
765 : 252 : bms_free(joinrelids);
766 : 252 : return joinrel;
767 : : }
768 : :
769 : : /* Build a grouped join relation for 'joinrel' if possible. */
158 rguo@postgresql.org 770 :GNC 204380 : make_grouped_join_rel(root, rel1, rel2, joinrel, sjinfo,
771 : : restrictlist);
772 : :
773 : : /* Add paths to the join relation. */
3288 rhaas@postgresql.org 774 :CBC 204380 : populate_joinrel_with_paths(root, rel1, rel2, joinrel, sjinfo,
775 : : restrictlist);
776 : :
777 : 204380 : bms_free(joinrelids);
778 : :
779 : 204380 : return joinrel;
780 : : }
781 : :
782 : : /*
783 : : * add_outer_joins_to_relids
784 : : * Add relids to input_relids to represent any outer joins that will be
785 : : * calculated at this join.
786 : : *
787 : : * input_relids is the union of the relid sets of the two input relations.
788 : : * Note that we modify this in-place and return it; caller must bms_copy()
789 : : * it first, if a separate value is desired.
790 : : *
791 : : * sjinfo represents the join being performed.
792 : : *
793 : : * If the current join completes the calculation of any outer joins that
794 : : * have been pushed down per outer-join identity 3, those relids will be
795 : : * added to the result along with sjinfo's own relid. If pushed_down_joins
796 : : * is not NULL, then also the SpecialJoinInfos for such added outer joins will
797 : : * be appended to *pushed_down_joins (so caller must initialize it to NIL).
798 : : */
799 : : Relids
1033 tgl@sss.pgh.pa.us 800 : 208474 : add_outer_joins_to_relids(PlannerInfo *root, Relids input_relids,
801 : : SpecialJoinInfo *sjinfo,
802 : : List **pushed_down_joins)
803 : : {
804 : : /* Nothing to do if this isn't an outer join with an assigned relid. */
805 [ + + + + ]: 208474 : if (sjinfo == NULL || sjinfo->ojrelid == 0)
806 : 151850 : return input_relids;
807 : :
808 : : /*
809 : : * If it's not a left join, we have no rules that would permit executing
810 : : * it in non-syntactic order, so just form the syntactic relid set. (This
811 : : * is just a quick-exit test; we'd come to the same conclusion anyway,
812 : : * since its commute_below_l and commute_above_l sets must be empty.)
813 : : */
814 [ + + ]: 56624 : if (sjinfo->jointype != JOIN_LEFT)
815 : 1178 : return bms_add_member(input_relids, sjinfo->ojrelid);
816 : :
817 : : /*
818 : : * We cannot add the OJ relid if this join has been pushed into the RHS of
819 : : * a syntactically-lower left join per OJ identity 3. (If it has, then we
820 : : * cannot claim that its outputs represent the final state of its RHS.)
821 : : * There will not be any other OJs that can be added either, so we're
822 : : * done.
823 : : */
824 [ + + ]: 55446 : if (!bms_is_subset(sjinfo->commute_below_l, input_relids))
825 : 2542 : return input_relids;
826 : :
827 : : /* OK to add OJ's own relid */
828 : 52904 : input_relids = bms_add_member(input_relids, sjinfo->ojrelid);
829 : :
830 : : /*
831 : : * Contrariwise, if we are now forming the final result of such a commuted
832 : : * pair of OJs, it's time to add the relid(s) of the pushed-down join(s).
833 : : * We can skip this if this join was never a candidate to be pushed up.
834 : : */
835 [ + + ]: 52904 : if (sjinfo->commute_above_l)
836 : : {
837 : 9408 : Relids commute_above_rels = bms_copy(sjinfo->commute_above_l);
838 : : ListCell *lc;
839 : :
840 : : /*
841 : : * The current join could complete the nulling of more than one
842 : : * pushed-down join, so we have to examine all the SpecialJoinInfos.
843 : : * Because join_info_list was built in bottom-up order, it's
844 : : * sufficient to traverse it once: an ojrelid we add in one loop
845 : : * iteration would not have affected decisions of earlier iterations.
846 : : */
847 [ + - + + : 32004 : foreach(lc, root->join_info_list)
+ + ]
848 : : {
849 : 22596 : SpecialJoinInfo *othersj = (SpecialJoinInfo *) lfirst(lc);
850 : :
851 [ + + ]: 22596 : if (othersj == sjinfo ||
852 [ + + - + ]: 13188 : othersj->ojrelid == 0 || othersj->jointype != JOIN_LEFT)
853 : 9414 : continue; /* definitely not interesting */
854 : :
855 [ + + ]: 13182 : if (!bms_is_member(othersj->ojrelid, commute_above_rels))
856 : 3700 : continue;
857 : :
858 : : /* Add it if not already present but conditions now satisfied */
859 [ + - + + ]: 18964 : if (!bms_is_member(othersj->ojrelid, input_relids) &&
860 [ + + ]: 18952 : bms_is_subset(othersj->min_lefthand, input_relids) &&
861 [ + + ]: 14249 : bms_is_subset(othersj->min_righthand, input_relids) &&
862 : 4779 : bms_is_subset(othersj->commute_below_l, input_relids))
863 : : {
864 : 4761 : input_relids = bms_add_member(input_relids, othersj->ojrelid);
865 : : /* report such pushed down outer joins, if asked */
866 [ + - ]: 4761 : if (pushed_down_joins != NULL)
867 : 4761 : *pushed_down_joins = lappend(*pushed_down_joins, othersj);
868 : :
869 : : /*
870 : : * We must also check any joins that othersj potentially
871 : : * commutes with. They likewise must appear later in
872 : : * join_info_list than othersj itself, so we can visit them
873 : : * later in this loop.
874 : : */
875 : 4761 : commute_above_rels = bms_add_members(commute_above_rels,
876 : 4761 : othersj->commute_above_l);
877 : : }
878 : : }
879 : : }
880 : :
881 : 52904 : return input_relids;
882 : : }
883 : :
884 : : /*
885 : : * make_grouped_join_rel
886 : : * Build a grouped join relation for the given "joinrel" if eager
887 : : * aggregation is applicable and the resulting grouped paths are considered
888 : : * useful.
889 : : *
890 : : * There are two strategies for generating grouped paths for a join relation:
891 : : *
892 : : * 1. Join a grouped (partially aggregated) input relation with a non-grouped
893 : : * input (e.g., AGG(B) JOIN A).
894 : : *
895 : : * 2. Apply partial aggregation (sorted or hashed) on top of existing
896 : : * non-grouped join paths (e.g., AGG(A JOIN B)).
897 : : *
898 : : * To limit planning effort and avoid an explosion of alternatives, we adopt a
899 : : * strategy where partial aggregation is only pushed to the lowest possible
900 : : * level in the join tree that is deemed useful. That is, if grouped paths can
901 : : * be built using the first strategy, we skip consideration of the second
902 : : * strategy for the same join level.
903 : : *
904 : : * Additionally, if there are multiple lowest useful levels where partial
905 : : * aggregation could be applied, such as in a join tree with relations A, B,
906 : : * and C where both "AGG(A JOIN B) JOIN C" and "A JOIN AGG(B JOIN C)" are valid
907 : : * placements, we choose only the first one encountered during join search.
908 : : * This avoids generating multiple versions of the same grouped relation based
909 : : * on different aggregation placements.
910 : : *
911 : : * These heuristics also ensure that all grouped paths for the same grouped
912 : : * relation produce the same set of rows, which is a basic assumption in the
913 : : * planner.
914 : : */
915 : : static void
158 rguo@postgresql.org 916 :GNC 214185 : make_grouped_join_rel(PlannerInfo *root, RelOptInfo *rel1,
917 : : RelOptInfo *rel2, RelOptInfo *joinrel,
918 : : SpecialJoinInfo *sjinfo, List *restrictlist)
919 : : {
920 : : RelOptInfo *grouped_rel;
921 : : RelOptInfo *grouped_rel1;
922 : : RelOptInfo *grouped_rel2;
923 : : bool rel1_empty;
924 : : bool rel2_empty;
925 : : Relids apply_agg_at;
926 : :
927 : : /*
928 : : * If there are no aggregate expressions or grouping expressions, eager
929 : : * aggregation is not possible.
930 : : */
931 [ + + ]: 214185 : if (root->agg_clause_list == NIL ||
932 [ + + ]: 9389 : root->group_expr_list == NIL)
933 : 204913 : return;
934 : :
935 : : /* Retrieve the grouped relations for the two input rels */
936 : 9272 : grouped_rel1 = rel1->grouped_rel;
937 : 9272 : grouped_rel2 = rel2->grouped_rel;
938 : :
939 [ + + - + ]: 9272 : rel1_empty = (grouped_rel1 == NULL || IS_DUMMY_REL(grouped_rel1));
940 [ + + - + ]: 9272 : rel2_empty = (grouped_rel2 == NULL || IS_DUMMY_REL(grouped_rel2));
941 : :
942 : : /* Find or construct a grouped joinrel for this joinrel */
943 : 9272 : grouped_rel = joinrel->grouped_rel;
944 [ + + ]: 9272 : if (grouped_rel == NULL)
945 : : {
946 : 8984 : RelAggInfo *agg_info = NULL;
947 : :
948 : : /*
949 : : * Prepare the information needed to create grouped paths for this
950 : : * join relation.
951 : : */
952 : 8984 : agg_info = create_rel_agg_info(root, joinrel, rel1_empty == rel2_empty);
953 [ + + ]: 8984 : if (agg_info == NULL)
954 : 420 : return;
955 : :
956 : : /*
957 : : * If grouped paths for the given join relation are not considered
958 : : * useful, and no grouped paths can be built by joining grouped input
959 : : * relations, skip building the grouped join relation.
960 : : */
961 [ + + + + ]: 8564 : if (!agg_info->agg_useful &&
962 : : (rel1_empty == rel2_empty))
963 : 129 : return;
964 : :
965 : : /* build the grouped relation */
966 : 8435 : grouped_rel = build_grouped_rel(root, joinrel);
967 : 8435 : grouped_rel->reltarget = agg_info->target;
968 : :
969 [ + + ]: 8435 : if (rel1_empty != rel2_empty)
970 : : {
971 : : /*
972 : : * If there is exactly one grouped input relation, then we can
973 : : * build grouped paths by joining the input relations. Set size
974 : : * estimates for the grouped join relation based on the input
975 : : * relations, and update the set of relids where partial
976 : : * aggregation is applied to that of the grouped input relation.
977 : : */
978 [ + + + + ]: 8105 : set_joinrel_size_estimates(root, grouped_rel,
979 : : rel1_empty ? rel1 : grouped_rel1,
980 : : rel2_empty ? rel2 : grouped_rel2,
981 : : sjinfo, restrictlist);
152 982 : 8105 : agg_info->apply_agg_at = rel1_empty ?
983 [ + + ]: 8105 : grouped_rel2->agg_info->apply_agg_at :
984 : 4016 : grouped_rel1->agg_info->apply_agg_at;
985 : : }
986 : : else
987 : : {
988 : : /*
989 : : * Otherwise, grouped paths can be built by applying partial
990 : : * aggregation on top of existing non-grouped join paths. Set
991 : : * size estimates for the grouped join relation based on the
992 : : * estimated number of groups, and track the set of relids where
993 : : * partial aggregation is applied. Note that these values may be
994 : : * updated later if it is determined that grouped paths can be
995 : : * constructed by joining other input relations.
996 : : */
158 997 : 330 : grouped_rel->rows = agg_info->grouped_rows;
152 998 : 330 : agg_info->apply_agg_at = bms_copy(joinrel->relids);
999 : : }
1000 : :
158 1001 : 8435 : grouped_rel->agg_info = agg_info;
1002 : 8435 : joinrel->grouped_rel = grouped_rel;
1003 : : }
1004 : :
1005 [ - + ]: 8723 : Assert(IS_GROUPED_REL(grouped_rel));
1006 : :
1007 : : /* We may have already proven this grouped join relation to be dummy. */
1008 [ - + ]: 8723 : if (IS_DUMMY_REL(grouped_rel))
158 rguo@postgresql.org 1009 :UNC 0 : return;
1010 : :
1011 : : /*
1012 : : * Nothing to do if there's no grouped input relation. Also, joining two
1013 : : * grouped relations is not currently supported.
1014 : : */
158 rguo@postgresql.org 1015 [ + + ]:GNC 8723 : if (rel1_empty == rel2_empty)
1016 : 474 : return;
1017 : :
1018 : : /*
1019 : : * Get the set of relids where partial aggregation is applied among the
1020 : : * given input relations.
1021 : : */
152 1022 : 8249 : apply_agg_at = rel1_empty ?
1023 [ + + ]: 8249 : grouped_rel2->agg_info->apply_agg_at :
1024 : 4160 : grouped_rel1->agg_info->apply_agg_at;
1025 : :
1026 : : /*
1027 : : * If it's not the designated level, skip building grouped paths.
1028 : : *
1029 : : * One exception is when it is a subset of the previously recorded level.
1030 : : * In that case, we need to update the designated level to this one, and
1031 : : * adjust the size estimates for the grouped join relation accordingly.
1032 : : * For example, suppose partial aggregation can be applied on top of (B
1033 : : * JOIN C). If we first construct the join as ((A JOIN B) JOIN C), we'd
1034 : : * record the designated level as including all three relations (A B C).
1035 : : * Later, when we consider (A JOIN (B JOIN C)), we encounter the smaller
1036 : : * (B C) join level directly. Since this is a subset of the previous
1037 : : * level and still valid for partial aggregation, we update the designated
1038 : : * level to (B C), and adjust the size estimates accordingly.
1039 : : */
1040 [ + + ]: 8249 : if (!bms_equal(apply_agg_at, grouped_rel->agg_info->apply_agg_at))
1041 : : {
1042 [ + - ]: 144 : if (bms_is_subset(apply_agg_at, grouped_rel->agg_info->apply_agg_at))
1043 : : {
1044 : : /* Adjust the size estimates for the grouped join relation. */
158 1045 [ + - - + ]: 144 : set_joinrel_size_estimates(root, grouped_rel,
1046 : : rel1_empty ? rel1 : grouped_rel1,
1047 : : rel2_empty ? rel2 : grouped_rel2,
1048 : : sjinfo, restrictlist);
152 1049 : 144 : grouped_rel->agg_info->apply_agg_at = apply_agg_at;
1050 : : }
1051 : : else
158 rguo@postgresql.org 1052 :UNC 0 : return;
1053 : : }
1054 : :
1055 : : /* Make paths for the grouped join relation. */
158 rguo@postgresql.org 1056 [ + + + + ]:GNC 8249 : populate_joinrel_with_paths(root,
1057 : : rel1_empty ? rel1 : grouped_rel1,
1058 : : rel2_empty ? rel2 : grouped_rel2,
1059 : : grouped_rel,
1060 : : sjinfo,
1061 : : restrictlist);
1062 : : }
1063 : :
1064 : : /*
1065 : : * populate_joinrel_with_paths
1066 : : * Add paths to the given joinrel for given pair of joining relations. The
1067 : : * SpecialJoinInfo provides details about the join and the restrictlist
1068 : : * contains the join clauses and the other clauses applicable for given pair
1069 : : * of the joining relations.
1070 : : */
1071 : : static void
3288 rhaas@postgresql.org 1072 :CBC 222434 : populate_joinrel_with_paths(PlannerInfo *root, RelOptInfo *rel1,
1073 : : RelOptInfo *rel2, RelOptInfo *joinrel,
1074 : : SpecialJoinInfo *sjinfo, List *restrictlist)
1075 : : {
1076 : : RelOptInfo *unique_rel2;
1077 : :
1078 : : /*
1079 : : * Consider paths using each rel as both outer and inner. Depending on
1080 : : * the join type, a provably empty outer or inner rel might mean the join
1081 : : * is provably empty too; in which case throw away any previously computed
1082 : : * paths and mark the join as dummy. (We do it this way since it's
1083 : : * conceivable that dummy-ness of a multi-element join might only be
1084 : : * noticeable for certain construction paths.)
1085 : : *
1086 : : * Also, a provably constant-false join restriction typically means that
1087 : : * we can skip evaluating one or both sides of the join. We do this by
1088 : : * marking the appropriate rel as dummy. For outer joins, a
1089 : : * constant-false restriction that is pushed down still means the whole
1090 : : * join is dummy, while a non-pushed-down one means that no inner rows
1091 : : * will join so we can treat the inner rel as dummy.
1092 : : *
1093 : : * We need only consider the jointypes that appear in join_info_list, plus
1094 : : * JOIN_INNER.
1095 : : */
6422 tgl@sss.pgh.pa.us 1096 [ + + + + : 222434 : switch (sjinfo->jointype)
+ - ]
1097 : : {
9315 1098 : 156697 : case JOIN_INNER:
6419 1099 [ + + + + : 313379 : if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
+ + ]
2886 1100 : 156682 : restriction_is_constant_false(restrictlist, joinrel, false))
1101 : : {
6419 1102 : 108 : mark_dummy_rel(joinrel);
6565 1103 : 108 : break;
1104 : : }
6422 1105 : 156589 : add_paths_to_joinrel(root, joinrel, rel1, rel2,
1106 : : JOIN_INNER, sjinfo,
1107 : : restrictlist);
1108 : 156589 : add_paths_to_joinrel(root, joinrel, rel2, rel1,
1109 : : JOIN_INNER, sjinfo,
1110 : : restrictlist);
9315 1111 : 156589 : break;
1112 : 56291 : case JOIN_LEFT:
5661 1113 [ + + + + ]: 112555 : if (is_dummy_rel(rel1) ||
2886 1114 : 56264 : restriction_is_constant_false(restrictlist, joinrel, true))
1115 : : {
6419 1116 : 43 : mark_dummy_rel(joinrel);
6565 1117 : 43 : break;
1118 : : }
2886 1119 [ + + + + ]: 56356 : if (restriction_is_constant_false(restrictlist, joinrel, false) &&
6419 1120 : 108 : bms_is_subset(rel2->relids, sjinfo->syn_righthand))
1121 : 96 : mark_dummy_rel(rel2);
6422 1122 : 56248 : add_paths_to_joinrel(root, joinrel, rel1, rel2,
1123 : : JOIN_LEFT, sjinfo,
1124 : : restrictlist);
1125 : 56248 : add_paths_to_joinrel(root, joinrel, rel2, rel1,
1126 : : JOIN_RIGHT, sjinfo,
1127 : : restrictlist);
9315 1128 : 56248 : break;
1129 : 885 : case JOIN_FULL:
5661 1130 [ - + - - : 1770 : if ((is_dummy_rel(rel1) && is_dummy_rel(rel2)) ||
+ + ]
2886 1131 : 885 : restriction_is_constant_false(restrictlist, joinrel, true))
1132 : : {
6419 1133 : 6 : mark_dummy_rel(joinrel);
6565 1134 : 6 : break;
1135 : : }
6422 1136 : 879 : add_paths_to_joinrel(root, joinrel, rel1, rel2,
1137 : : JOIN_FULL, sjinfo,
1138 : : restrictlist);
1139 : 879 : add_paths_to_joinrel(root, joinrel, rel2, rel1,
1140 : : JOIN_FULL, sjinfo,
1141 : : restrictlist);
1142 : :
1143 : : /*
1144 : : * If there are join quals that aren't mergeable or hashable, we
1145 : : * may not be able to build any valid plan. Complain here so that
1146 : : * we can give a somewhat-useful error message. (Since we have no
1147 : : * flexibility of planning for a full join, there's no chance of
1148 : : * succeeding later with another pair of input rels.)
1149 : : */
5554 1150 [ - + ]: 879 : if (joinrel->pathlist == NIL)
5554 tgl@sss.pgh.pa.us 1151 [ # # ]:UBC 0 : ereport(ERROR,
1152 : : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1153 : : errmsg("FULL JOIN is only supported with merge-joinable or hash-joinable join conditions")));
8455 tgl@sss.pgh.pa.us 1154 :CBC 879 : break;
6422 1155 : 4073 : case JOIN_SEMI:
1156 : :
1157 : : /*
1158 : : * We might have a normal semijoin, or a case where we don't have
1159 : : * enough rels to do the semijoin but can unique-ify the RHS and
1160 : : * then do an innerjoin (see comments in join_is_legal). In the
1161 : : * latter case we can't apply JOIN_SEMI joining.
1162 : : */
6322 1163 [ + + + - ]: 7931 : if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) &&
1164 : 3858 : bms_is_subset(sjinfo->min_righthand, rel2->relids))
1165 : : {
1166 [ + + + - : 7713 : if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
+ + ]
2886 1167 : 3855 : restriction_is_constant_false(restrictlist, joinrel, false))
1168 : : {
6322 1169 : 6 : mark_dummy_rel(joinrel);
1170 : 6 : break;
1171 : : }
1172 : 3852 : add_paths_to_joinrel(root, joinrel, rel1, rel2,
1173 : : JOIN_SEMI, sjinfo,
1174 : : restrictlist);
618 rguo@postgresql.org 1175 : 3852 : add_paths_to_joinrel(root, joinrel, rel2, rel1,
1176 : : JOIN_RIGHT_SEMI, sjinfo,
1177 : : restrictlist);
1178 : : }
1179 : :
1180 : : /*
1181 : : * If we know how to unique-ify the RHS and one input rel is
1182 : : * exactly the RHS (not a superset) we can consider unique-ifying
1183 : : * it and then doing a regular join. (The create_unique_paths
1184 : : * check here is probably redundant with what join_is_legal did,
1185 : : * but if so the check is cheap because it's cached. So test
1186 : : * anyway to be sure.)
1187 : : */
6422 tgl@sss.pgh.pa.us 1188 [ + - + + ]: 8134 : if (bms_equal(sjinfo->syn_righthand, rel2->relids) &&
208 rguo@postgresql.org 1189 :GNC 4067 : (unique_rel2 = create_unique_paths(root, rel2, sjinfo)) != NULL)
1190 : : {
5661 tgl@sss.pgh.pa.us 1191 [ + - + - :CBC 6388 : if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
- + ]
2886 1192 : 3194 : restriction_is_constant_false(restrictlist, joinrel, false))
1193 : : {
5661 tgl@sss.pgh.pa.us 1194 :UBC 0 : mark_dummy_rel(joinrel);
1195 : 0 : break;
1196 : : }
208 rguo@postgresql.org 1197 :GNC 3194 : add_paths_to_joinrel(root, joinrel, rel1, unique_rel2,
1198 : : JOIN_UNIQUE_INNER, sjinfo,
1199 : : restrictlist);
1200 : 3194 : add_paths_to_joinrel(root, joinrel, unique_rel2, rel1,
1201 : : JOIN_UNIQUE_OUTER, sjinfo,
1202 : : restrictlist);
1203 : : }
8455 tgl@sss.pgh.pa.us 1204 :CBC 4067 : break;
6422 1205 : 4488 : case JOIN_ANTI:
5661 1206 [ + - - + ]: 8976 : if (is_dummy_rel(rel1) ||
2886 1207 : 4488 : restriction_is_constant_false(restrictlist, joinrel, true))
1208 : : {
6419 tgl@sss.pgh.pa.us 1209 :UBC 0 : mark_dummy_rel(joinrel);
6565 1210 : 0 : break;
1211 : : }
2886 tgl@sss.pgh.pa.us 1212 [ - + - - ]:CBC 4488 : if (restriction_is_constant_false(restrictlist, joinrel, false) &&
6419 tgl@sss.pgh.pa.us 1213 :UBC 0 : bms_is_subset(rel2->relids, sjinfo->syn_righthand))
1214 : 0 : mark_dummy_rel(rel2);
6422 tgl@sss.pgh.pa.us 1215 :CBC 4488 : add_paths_to_joinrel(root, joinrel, rel1, rel2,
1216 : : JOIN_ANTI, sjinfo,
1217 : : restrictlist);
1075 1218 : 4488 : add_paths_to_joinrel(root, joinrel, rel2, rel1,
1219 : : JOIN_RIGHT_ANTI, sjinfo,
1220 : : restrictlist);
8455 1221 : 4488 : break;
9315 tgl@sss.pgh.pa.us 1222 :UBC 0 : default:
1223 : : /* other values not expected here */
6422 1224 [ # # ]: 0 : elog(ERROR, "unrecognized join type: %d", (int) sjinfo->jointype);
1225 : : break;
1226 : : }
1227 : :
1228 : : /* Apply partitionwise join technique, if possible. */
2949 peter_e@gmx.net 1229 :CBC 222434 : try_partitionwise_join(root, rel1, rel2, joinrel, sjinfo, restrictlist);
10841 scrappy@hub.org 1230 : 222434 : }
1231 : :
1232 : :
1233 : : /*
1234 : : * have_join_order_restriction
1235 : : * Detect whether the two relations should be joined to satisfy
1236 : : * a join-order restriction arising from special or lateral joins.
1237 : : *
1238 : : * In practice this is always used with have_relevant_joinclause(), and so
1239 : : * could be merged with that function, but it seems clearer to separate the
1240 : : * two concerns. We need this test because there are degenerate cases where
1241 : : * a clauseless join must be performed to satisfy join-order restrictions.
1242 : : * Also, if one rel has a lateral reference to the other, or both are needed
1243 : : * to compute some PHV, we should consider joining them even if the join would
1244 : : * be clauseless.
1245 : : *
1246 : : * Note: this is only a problem if one side of a degenerate outer join
1247 : : * contains multiple rels, or a clauseless join is required within an
1248 : : * IN/EXISTS RHS; else we will find a join path via the "last ditch" case in
1249 : : * join_search_one_level(). We could dispense with this test if we were
1250 : : * willing to try bushy plans in the "last ditch" case, but that seems much
1251 : : * less efficient.
1252 : : */
1253 : : bool
6967 tgl@sss.pgh.pa.us 1254 : 50786 : have_join_order_restriction(PlannerInfo *root,
1255 : : RelOptInfo *rel1, RelOptInfo *rel2)
1256 : : {
6715 1257 : 50786 : bool result = false;
1258 : : ListCell *l;
1259 : :
1260 : : /*
1261 : : * If either side has a direct lateral reference to the other, attempt the
1262 : : * join regardless of outer-join considerations.
1263 : : */
3747 1264 [ + + + + ]: 94844 : if (bms_overlap(rel1->relids, rel2->direct_lateral_relids) ||
1265 : 44058 : bms_overlap(rel2->relids, rel1->direct_lateral_relids))
1266 : 7681 : return true;
1267 : :
1268 : : /*
1269 : : * Likewise, if both rels are needed to compute some PlaceHolderVar,
1270 : : * attempt the join regardless of outer-join considerations. (This is not
1271 : : * very desirable, because a PHV with a large eval_at set will cause a lot
1272 : : * of probably-useless joins to be considered, but failing to do this can
1273 : : * cause us to fail to construct a plan at all.)
1274 : : */
1275 [ + + + + : 44046 : foreach(l, root->placeholder_list)
+ + ]
1276 : : {
1277 : 971 : PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(l);
1278 : :
1279 [ + + + + ]: 1166 : if (bms_is_subset(rel1->relids, phinfo->ph_eval_at) &&
1280 : 195 : bms_is_subset(rel2->relids, phinfo->ph_eval_at))
1281 : 30 : return true;
1282 : : }
1283 : :
1284 : : /*
1285 : : * It's possible that the rels correspond to the left and right sides of a
1286 : : * degenerate outer join, that is, one with no joinclause mentioning the
1287 : : * non-nullable side; in which case we should force the join to occur.
1288 : : *
1289 : : * Also, the two rels could represent a clauseless join that has to be
1290 : : * completed to build up the LHS or RHS of an outer join.
1291 : : */
6422 1292 [ + + + + : 107827 : foreach(l, root->join_info_list)
+ + ]
1293 : : {
1294 : 65515 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
1295 : :
1296 : : /* ignore full joins --- other mechanisms handle them */
1297 [ + + ]: 65515 : if (sjinfo->jointype == JOIN_FULL)
6967 1298 : 21 : continue;
1299 : :
1300 : : /* Can we perform the SJ with these rels? */
6422 1301 [ + + + + ]: 79720 : if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) &&
1302 : 14226 : bms_is_subset(sjinfo->min_righthand, rel2->relids))
1303 : : {
6715 1304 : 559 : result = true;
1305 : 559 : break;
1306 : : }
6422 1307 [ + + + + ]: 68762 : if (bms_is_subset(sjinfo->min_lefthand, rel2->relids) &&
1308 : 3827 : bms_is_subset(sjinfo->min_righthand, rel1->relids))
1309 : : {
6715 1310 : 108 : result = true;
1311 : 108 : break;
1312 : : }
1313 : :
1314 : : /*
1315 : : * Might we need to join these rels to complete the RHS? We have to
1316 : : * use "overlap" tests since either rel might include a lower SJ that
1317 : : * has been proven to commute with this one.
1318 : : */
6422 1319 [ + + + + ]: 78115 : if (bms_overlap(sjinfo->min_righthand, rel1->relids) &&
1320 : 13288 : bms_overlap(sjinfo->min_righthand, rel2->relids))
1321 : : {
6715 1322 : 60 : result = true;
1323 : 60 : break;
1324 : : }
1325 : :
1326 : : /* Likewise for the LHS. */
6422 1327 [ + + + + ]: 79950 : if (bms_overlap(sjinfo->min_lefthand, rel1->relids) &&
1328 : 15183 : bms_overlap(sjinfo->min_lefthand, rel2->relids))
1329 : : {
6715 1330 : 36 : result = true;
1331 : 36 : break;
1332 : : }
1333 : : }
1334 : :
1335 : : /*
1336 : : * We do not force the join to occur if either input rel can legally be
1337 : : * joined to anything else using joinclauses. This essentially means that
1338 : : * clauseless bushy joins are put off as long as possible. The reason is
1339 : : * that when there is a join order restriction high up in the join tree
1340 : : * (that is, with many rels inside the LHS or RHS), we would otherwise
1341 : : * expend lots of effort considering very stupid join combinations within
1342 : : * its LHS or RHS.
1343 : : */
1344 [ + + ]: 43075 : if (result)
1345 : : {
1346 [ + + + + ]: 1457 : if (has_legal_joinclause(root, rel1) ||
1347 : 694 : has_legal_joinclause(root, rel2))
1348 : 126 : result = false;
1349 : : }
1350 : :
1351 : 43075 : return result;
1352 : : }
1353 : :
1354 : :
1355 : : /*
1356 : : * has_join_restriction
1357 : : * Detect whether the specified relation has join-order restrictions,
1358 : : * due to being inside an outer join or an IN (sub-SELECT),
1359 : : * or participating in any LATERAL references or multi-rel PHVs.
1360 : : *
1361 : : * Essentially, this tests whether have_join_order_restriction() could
1362 : : * succeed with this rel and some other one. It's OK if we sometimes
1363 : : * say "true" incorrectly. (Therefore, we don't bother with the relatively
1364 : : * expensive has_legal_joinclause test.)
1365 : : */
1366 : : static bool
6967 1367 : 17182 : has_join_restriction(PlannerInfo *root, RelOptInfo *rel)
1368 : : {
1369 : : ListCell *l;
1370 : :
3747 1371 [ + + + + ]: 17182 : if (rel->lateral_relids != NULL || rel->lateral_referencers != NULL)
1372 : 10068 : return true;
1373 : :
1374 [ + + + + : 7534 : foreach(l, root->placeholder_list)
+ + ]
1375 : : {
1376 : 444 : PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(l);
1377 : :
1378 [ + + ]: 444 : if (bms_is_subset(rel->relids, phinfo->ph_eval_at) &&
1379 [ + + ]: 114 : !bms_equal(rel->relids, phinfo->ph_eval_at))
4949 1380 : 24 : return true;
1381 : : }
1382 : :
6422 1383 [ + + + + : 7528 : foreach(l, root->join_info_list)
+ + ]
1384 : : {
1385 : 1562 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
1386 : :
1387 : : /* ignore full joins --- other mechanisms preserve their ordering */
1388 [ + + ]: 1562 : if (sjinfo->jointype == JOIN_FULL)
6967 1389 : 43 : continue;
1390 : :
1391 : : /* ignore if SJ is already contained in rel */
6422 1392 [ + + + + ]: 2356 : if (bms_is_subset(sjinfo->min_lefthand, rel->relids) &&
1393 : 837 : bms_is_subset(sjinfo->min_righthand, rel->relids))
6967 1394 : 224 : continue;
1395 : :
1396 : : /* restricted if it overlaps LHS or RHS, but doesn't contain SJ */
6422 1397 [ + + + + ]: 1965 : if (bms_overlap(sjinfo->min_lefthand, rel->relids) ||
1398 : 670 : bms_overlap(sjinfo->min_righthand, rel->relids))
6967 1399 : 1124 : return true;
1400 : : }
1401 : :
1402 : 5966 : return false;
1403 : : }
1404 : :
1405 : :
1406 : : /*
1407 : : * has_legal_joinclause
1408 : : * Detect whether the specified relation can legally be joined
1409 : : * to any other rels using join clauses.
1410 : : *
1411 : : * We consider only joins to single other relations in the current
1412 : : * initial_rels list. This is sufficient to get a "true" result in most real
1413 : : * queries, and an occasional erroneous "false" will only cost a bit more
1414 : : * planning time. The reason for this limitation is that considering joins to
1415 : : * other joins would require proving that the other join rel can legally be
1416 : : * formed, which seems like too much trouble for something that's only a
1417 : : * heuristic to save planning time. (Note: we must look at initial_rels
1418 : : * and not all of the query, since when we are planning a sub-joinlist we
1419 : : * may be forced to make clauseless joins within initial_rels even though
1420 : : * there are join clauses linking to other parts of the query.)
1421 : : */
1422 : : static bool
6715 1423 : 1457 : has_legal_joinclause(PlannerInfo *root, RelOptInfo *rel)
1424 : : {
1425 : : ListCell *lc;
1426 : :
6638 1427 [ + - + + : 5379 : foreach(lc, root->initial_rels)
+ + ]
1428 : : {
1429 : 4048 : RelOptInfo *rel2 = (RelOptInfo *) lfirst(lc);
1430 : :
1431 : : /* ignore rels that are already in "rel" */
6715 1432 [ + + ]: 4048 : if (bms_overlap(rel->relids, rel2->relids))
1433 : 1712 : continue;
1434 : :
1435 [ + + ]: 2336 : if (have_relevant_joinclause(root, rel, rel2))
1436 : : {
1437 : : Relids joinrelids;
1438 : : SpecialJoinInfo *sjinfo;
1439 : : bool reversed;
1440 : :
1441 : : /* join_is_legal needs relids of the union */
1442 : 228 : joinrelids = bms_union(rel->relids, rel2->relids);
1443 : :
6422 1444 [ + + ]: 228 : if (join_is_legal(root, rel, rel2, joinrelids,
1445 : : &sjinfo, &reversed))
1446 : : {
1447 : : /* Yes, this will work */
6715 1448 : 126 : bms_free(joinrelids);
1449 : 126 : return true;
1450 : : }
1451 : :
1452 : 102 : bms_free(joinrelids);
1453 : : }
1454 : : }
1455 : :
1456 : 1331 : return false;
1457 : : }
1458 : :
1459 : :
1460 : : /*
1461 : : * is_dummy_rel --- has relation been proven empty?
1462 : : */
1463 : : bool
6565 1464 : 1692518 : is_dummy_rel(RelOptInfo *rel)
1465 : : {
1466 : : Path *path;
1467 : :
1468 : : /*
1469 : : * A rel that is known dummy will have just one path that is a childless
1470 : : * Append. (Even if somehow it has more paths, a childless Append will
1471 : : * have cost zero and hence should be at the front of the pathlist.)
1472 : : */
2565 1473 [ + + ]: 1692518 : if (rel->pathlist == NIL)
1474 : 826717 : return false;
1475 : 865801 : path = (Path *) linitial(rel->pathlist);
1476 : :
1477 : : /*
1478 : : * Initially, a dummy path will just be a childless Append. But in later
1479 : : * planning stages we might stick a ProjectSetPath and/or ProjectionPath
1480 : : * on top, since Append can't project. Rather than make assumptions about
1481 : : * which combinations can occur, just descend through whatever we find.
1482 : : */
1483 : : for (;;)
1484 : : {
1485 [ + + ]: 908493 : if (IsA(path, ProjectionPath))
1486 : 37608 : path = ((ProjectionPath *) path)->subpath;
1487 [ + + ]: 870885 : else if (IsA(path, ProjectSetPath))
1488 : 5084 : path = ((ProjectSetPath *) path)->subpath;
1489 : : else
1490 : 865801 : break;
1491 : : }
1492 [ + + + + ]: 865801 : if (IS_DUMMY_APPEND(path))
1493 : 3099 : return true;
1494 : 862702 : return false;
1495 : : }
1496 : :
1497 : : /*
1498 : : * Mark a relation as proven empty.
1499 : : *
1500 : : * During GEQO planning, this can get invoked more than once on the same
1501 : : * baserel struct, so it's worth checking to see if the rel is already marked
1502 : : * dummy.
1503 : : *
1504 : : * Also, when called during GEQO join planning, we are in a short-lived
1505 : : * memory context. We must make sure that the dummy path attached to a
1506 : : * baserel survives the GEQO cycle, else the baserel is trashed for future
1507 : : * GEQO cycles. On the other hand, when we are marking a joinrel during GEQO,
1508 : : * we don't want the dummy path to clutter the main planning context. Upshot
1509 : : * is that the best solution is to explicitly make the dummy path in the same
1510 : : * context the given RelOptInfo is in.
1511 : : */
1512 : : void
6419 1513 : 370 : mark_dummy_rel(RelOptInfo *rel)
1514 : : {
1515 : : MemoryContext oldcontext;
33 rhaas@postgresql.org 1516 :GNC 370 : AppendPathInput in = {0};
1517 : :
1518 : : /* Already marked? */
5450 tgl@sss.pgh.pa.us 1519 [ + + ]:CBC 370 : if (is_dummy_rel(rel))
1520 : 9 : return;
1521 : :
1522 : : /* No, so choose correct context to make the dummy path in */
1523 : 361 : oldcontext = MemoryContextSwitchTo(GetMemoryChunkContext(rel));
1524 : :
1525 : : /* Set dummy size estimate */
6565 1526 : 361 : rel->rows = 0;
1527 : :
1528 : : /* Evict any previously chosen paths */
1529 : 361 : rel->pathlist = NIL;
3707 rhaas@postgresql.org 1530 : 361 : rel->partial_pathlist = NIL;
1531 : :
1532 : : /* Set up the dummy path */
33 rhaas@postgresql.org 1533 :GNC 361 : add_path(rel, (Path *) create_append_path(NULL, rel, in,
1534 : : NIL, rel->lateral_relids,
1535 : : 0, false, -1));
1536 : :
1537 : : /* Set or update cheapest_total_path and related fields */
6419 tgl@sss.pgh.pa.us 1538 :CBC 361 : set_cheapest(rel);
1539 : :
5450 1540 : 361 : MemoryContextSwitchTo(oldcontext);
1541 : : }
1542 : :
1543 : :
1544 : : /*
1545 : : * restriction_is_constant_false --- is a restrictlist just FALSE?
1546 : : *
1547 : : * In cases where a qual is provably constant FALSE, eval_const_expressions
1548 : : * will generally have thrown away anything that's ANDed with it. In outer
1549 : : * join situations this will leave us computing cartesian products only to
1550 : : * decide there's no match for an outer row, which is pretty stupid. So,
1551 : : * we need to detect the case.
1552 : : *
1553 : : * If only_pushed_down is true, then consider only quals that are pushed-down
1554 : : * from the point of view of the joinrel.
1555 : : */
1556 : : static bool
2886 1557 : 286104 : restriction_is_constant_false(List *restrictlist,
1558 : : RelOptInfo *joinrel,
1559 : : bool only_pushed_down)
1560 : : {
1561 : : ListCell *lc;
1562 : :
1563 : : /*
1564 : : * Despite the above comment, the restriction list we see here might
1565 : : * possibly have other members besides the FALSE constant, since other
1566 : : * quals could get "pushed down" to the outer join level. So we check
1567 : : * each member of the list.
1568 : : */
6419 1569 [ + + + + : 617353 : foreach(lc, restrictlist)
+ + ]
1570 : : {
3261 1571 : 331475 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
1572 : :
2886 1573 [ + + + + : 331475 : if (only_pushed_down && !RINFO_IS_PUSHED_DOWN(rinfo, joinrel->relids))
+ - ]
5661 1574 : 78059 : continue;
1575 : :
6419 1576 [ + - + + ]: 253416 : if (rinfo->clause && IsA(rinfo->clause, Const))
1577 : : {
6121 bruce@momjian.us 1578 : 2763 : Const *con = (Const *) rinfo->clause;
1579 : :
1580 : : /* constant NULL is as good as constant FALSE for our purposes */
6419 tgl@sss.pgh.pa.us 1581 [ + + ]: 2763 : if (con->constisnull)
1582 : 226 : return true;
1583 [ + + ]: 2709 : if (!DatumGetBool(con->constvalue))
1584 : 172 : return true;
1585 : : }
1586 : : }
1587 : 285878 : return false;
1588 : : }
1589 : :
1590 : : /*
1591 : : * Assess whether join between given two partitioned relations can be broken
1592 : : * down into joins between matching partitions; a technique called
1593 : : * "partitionwise join"
1594 : : *
1595 : : * Partitionwise join is possible when a. Joining relations have same
1596 : : * partitioning scheme b. There exists an equi-join between the partition keys
1597 : : * of the two relations.
1598 : : *
1599 : : * Partitionwise join is planned as follows (details: optimizer/README.)
1600 : : *
1601 : : * 1. Create the RelOptInfos for joins between matching partitions i.e
1602 : : * child-joins and add paths to them.
1603 : : *
1604 : : * 2. Construct Append or MergeAppend paths across the set of child joins.
1605 : : * This second phase is implemented by generate_partitionwise_join_paths().
1606 : : *
1607 : : * The RelOptInfo, SpecialJoinInfo and restrictlist for each child join are
1608 : : * obtained by translating the respective parent join structures.
1609 : : */
1610 : : static void
2949 peter_e@gmx.net 1611 : 222434 : try_partitionwise_join(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2,
1612 : : RelOptInfo *joinrel, SpecialJoinInfo *parent_sjinfo,
1613 : : List *parent_restrictlist)
1614 : : {
2610 efujita@postgresql.o 1615 [ + + + + ]: 222434 : bool rel1_is_simple = IS_SIMPLE_REL(rel1);
1616 [ + + + + ]: 222434 : bool rel2_is_simple = IS_SIMPLE_REL(rel2);
2167 1617 : 222434 : List *parts1 = NIL;
1618 : 222434 : List *parts2 = NIL;
1619 : 222434 : ListCell *lcr1 = NULL;
1620 : 222434 : ListCell *lcr2 = NULL;
1621 : : int cnt_parts;
1622 : :
1623 : : /* Guard against stack overflow due to overly deep partition hierarchy. */
3082 rhaas@postgresql.org 1624 : 222434 : check_stack_depth();
1625 : :
1626 : : /* Nothing to do, if the join relation is not partitioned. */
2167 efujita@postgresql.o 1627 [ + + + + ]: 222434 : if (joinrel->part_scheme == NULL || joinrel->nparts == 0)
3082 rhaas@postgresql.org 1628 : 218574 : return;
1629 : :
1630 : : /* The join relation should have consider_partitionwise_join set. */
2753 efujita@postgresql.o 1631 [ - + ]: 3929 : Assert(joinrel->consider_partitionwise_join);
1632 : :
1633 : : /*
1634 : : * We can not perform partitionwise join if either of the joining
1635 : : * relations is not partitioned.
1636 : : */
2167 1637 [ + - + + : 3929 : if (!IS_PARTITIONED_REL(rel1) || !IS_PARTITIONED_REL(rel2))
+ + + - +
- + - + -
+ - + - -
+ ]
1638 : 9 : return;
1639 : :
3082 rhaas@postgresql.org 1640 [ + - + - : 3920 : Assert(REL_HAS_ALL_PART_PROPS(rel1) && REL_HAS_ALL_PART_PROPS(rel2));
+ - + - +
- + - + -
+ - + - +
- + - -
+ ]
1641 : :
1642 : : /* The joining relations should have consider_partitionwise_join set. */
2753 efujita@postgresql.o 1643 [ + - - + ]: 3920 : Assert(rel1->consider_partitionwise_join &&
1644 : : rel2->consider_partitionwise_join);
1645 : :
1646 : : /*
1647 : : * The partition scheme of the join relation should match that of the
1648 : : * joining relations.
1649 : : */
3082 rhaas@postgresql.org 1650 [ + - - + ]: 3920 : Assert(joinrel->part_scheme == rel1->part_scheme &&
1651 : : joinrel->part_scheme == rel2->part_scheme);
1652 : :
2167 efujita@postgresql.o 1653 [ + + - + ]: 3920 : Assert(!(joinrel->partbounds_merged && (joinrel->nparts <= 0)));
1654 : :
1655 : 3920 : compute_partition_bounds(root, rel1, rel2, joinrel, parent_sjinfo,
1656 : : &parts1, &parts2);
1657 : :
1658 [ + + ]: 3920 : if (joinrel->partbounds_merged)
1659 : : {
1660 : 384 : lcr1 = list_head(parts1);
1661 : 384 : lcr2 = list_head(parts2);
1662 : : }
1663 : :
1664 : : /*
1665 : : * Create child-join relations for this partitioned join, if those don't
1666 : : * exist. Add paths to child-joins for a pair of child relations
1667 : : * corresponding to the given pair of parent relations.
1668 : : */
1669 [ + + ]: 13763 : for (cnt_parts = 0; cnt_parts < joinrel->nparts; cnt_parts++)
1670 : : {
1671 : : RelOptInfo *child_rel1;
1672 : : RelOptInfo *child_rel2;
1673 : : bool rel1_empty;
1674 : : bool rel2_empty;
1675 : : SpecialJoinInfo *child_sjinfo;
1676 : : List *child_restrictlist;
1677 : : RelOptInfo *child_joinrel;
1678 : : AppendRelInfo **appinfos;
1679 : : int nappinfos;
1680 : : Relids child_relids;
1681 : :
1682 [ + + ]: 9903 : if (joinrel->partbounds_merged)
1683 : : {
1684 : 1005 : child_rel1 = lfirst_node(RelOptInfo, lcr1);
1685 : 1005 : child_rel2 = lfirst_node(RelOptInfo, lcr2);
1686 : 1005 : lcr1 = lnext(parts1, lcr1);
1687 : 1005 : lcr2 = lnext(parts2, lcr2);
1688 : : }
1689 : : else
1690 : : {
1691 : 8898 : child_rel1 = rel1->part_rels[cnt_parts];
1692 : 8898 : child_rel2 = rel2->part_rels[cnt_parts];
1693 : : }
1694 : :
1695 [ + + - + ]: 9903 : rel1_empty = (child_rel1 == NULL || IS_DUMMY_REL(child_rel1));
1696 [ + + - + ]: 9903 : rel2_empty = (child_rel2 == NULL || IS_DUMMY_REL(child_rel2));
1697 : :
1698 : : /*
1699 : : * Check for cases where we can prove that this segment of the join
1700 : : * returns no rows, due to one or both inputs being empty (including
1701 : : * inputs that have been pruned away entirely). If so just ignore it.
1702 : : * These rules are equivalent to populate_joinrel_with_paths's rules
1703 : : * for dummy input relations.
1704 : : */
2542 tgl@sss.pgh.pa.us 1705 [ + + + - ]: 9903 : switch (parent_sjinfo->jointype)
1706 : : {
1707 : 8494 : case JOIN_INNER:
1708 : : case JOIN_SEMI:
1709 [ + + + + ]: 8494 : if (rel1_empty || rel2_empty)
1710 : 38 : continue; /* ignore this join segment */
1711 : 8470 : break;
1712 : 1048 : case JOIN_LEFT:
1713 : : case JOIN_ANTI:
1714 [ + + ]: 1048 : if (rel1_empty)
1715 : 14 : continue; /* ignore this join segment */
1716 : 1034 : break;
1717 : 361 : case JOIN_FULL:
1718 [ + + - + ]: 361 : if (rel1_empty && rel2_empty)
2542 tgl@sss.pgh.pa.us 1719 :UBC 0 : continue; /* ignore this join segment */
2542 tgl@sss.pgh.pa.us 1720 :CBC 361 : break;
2542 tgl@sss.pgh.pa.us 1721 :UBC 0 : default:
1722 : : /* other values not expected here */
1723 [ # # ]: 0 : elog(ERROR, "unrecognized join type: %d",
1724 : : (int) parent_sjinfo->jointype);
1725 : : break;
1726 : : }
1727 : :
1728 : : /*
1729 : : * If a child has been pruned entirely then we can't generate paths
1730 : : * for it, so we have to reject partitionwise joining unless we were
1731 : : * able to eliminate this partition above.
1732 : : */
2542 tgl@sss.pgh.pa.us 1733 [ + + + + ]:CBC 9865 : if (child_rel1 == NULL || child_rel2 == NULL)
1734 : : {
1735 : : /*
1736 : : * Mark the joinrel as unpartitioned so that later functions treat
1737 : : * it correctly.
1738 : : */
1739 : 60 : joinrel->nparts = 0;
1740 : 60 : return;
1741 : : }
1742 : :
1743 : : /*
1744 : : * If a leaf relation has consider_partitionwise_join=false, it means
1745 : : * that it's a dummy relation for which we skipped setting up tlist
1746 : : * expressions and adding EC members in set_append_rel_size(), so
1747 : : * again we have to fail here.
1748 : : */
2610 efujita@postgresql.o 1749 [ + + - + ]: 9805 : if (rel1_is_simple && !child_rel1->consider_partitionwise_join)
1750 : : {
2610 efujita@postgresql.o 1751 [ # # ]:UBC 0 : Assert(child_rel1->reloptkind == RELOPT_OTHER_MEMBER_REL);
1752 [ # # ]: 0 : Assert(IS_DUMMY_REL(child_rel1));
2542 tgl@sss.pgh.pa.us 1753 : 0 : joinrel->nparts = 0;
1754 : 0 : return;
1755 : : }
2610 efujita@postgresql.o 1756 [ + + - + ]:CBC 9805 : if (rel2_is_simple && !child_rel2->consider_partitionwise_join)
1757 : : {
2610 efujita@postgresql.o 1758 [ # # ]:UBC 0 : Assert(child_rel2->reloptkind == RELOPT_OTHER_MEMBER_REL);
1759 [ # # ]: 0 : Assert(IS_DUMMY_REL(child_rel2));
2542 tgl@sss.pgh.pa.us 1760 : 0 : joinrel->nparts = 0;
1761 : 0 : return;
1762 : : }
1763 : :
1764 : : /* We should never try to join two overlapping sets of rels. */
3082 rhaas@postgresql.org 1765 [ - + ]:CBC 9805 : Assert(!bms_overlap(child_rel1->relids, child_rel2->relids));
1766 : :
1767 : : /*
1768 : : * Construct SpecialJoinInfo from parent join relations's
1769 : : * SpecialJoinInfo.
1770 : : */
1771 : 9805 : child_sjinfo = build_child_join_sjinfo(root, parent_sjinfo,
1772 : : child_rel1->relids,
1773 : : child_rel2->relids);
1774 : :
1775 : : /* Find the AppendRelInfo structures */
594 rguo@postgresql.org 1776 : 9805 : child_relids = bms_union(child_rel1->relids, child_rel2->relids);
1777 : 9805 : appinfos = find_appinfos_by_relids(root, child_relids,
1778 : : &nappinfos);
1779 : :
1780 : : /*
1781 : : * Construct restrictions applicable to the child join from those
1782 : : * applicable to the parent join.
1783 : : */
1784 : : child_restrictlist =
3082 rhaas@postgresql.org 1785 : 9805 : (List *) adjust_appendrel_attrs(root,
1786 : : (Node *) parent_restrictlist,
1787 : : nappinfos, appinfos);
1788 : :
1789 : : /* Find or construct the child join's RelOptInfo */
1790 : 9805 : child_joinrel = joinrel->part_rels[cnt_parts];
1791 [ + + ]: 9805 : if (!child_joinrel)
1792 : : {
1793 : 9257 : child_joinrel = build_child_join_rel(root, child_rel1, child_rel2,
1794 : : joinrel, child_restrictlist,
1795 : : child_sjinfo, nappinfos, appinfos);
1796 : 9257 : joinrel->part_rels[cnt_parts] = child_joinrel;
1685 drowley@postgresql.o 1797 : 9257 : joinrel->live_parts = bms_add_member(joinrel->live_parts, cnt_parts);
2167 efujita@postgresql.o 1798 : 9257 : joinrel->all_partrels = bms_add_members(joinrel->all_partrels,
1799 : 9257 : child_joinrel->relids);
1800 : : }
1801 : :
1802 : : /* Assert we got the right one */
967 tgl@sss.pgh.pa.us 1803 [ - + ]: 9805 : Assert(bms_equal(child_joinrel->relids,
1804 : : adjust_child_relids(joinrel->relids,
1805 : : nappinfos, appinfos)));
1806 : :
1807 : : /* Build a grouped join relation for 'child_joinrel' if possible */
158 rguo@postgresql.org 1808 :GNC 9805 : make_grouped_join_rel(root, child_rel1, child_rel2,
1809 : : child_joinrel, child_sjinfo,
1810 : : child_restrictlist);
1811 : :
1812 : : /* And make paths for the child join */
3082 rhaas@postgresql.org 1813 :CBC 9805 : populate_joinrel_with_paths(root, child_rel1, child_rel2,
1814 : : child_joinrel, child_sjinfo,
1815 : : child_restrictlist);
1816 : :
1817 : : /*
1818 : : * When there are thousands of partitions involved, this loop will
1819 : : * accumulate a significant amount of memory usage from objects that
1820 : : * are only needed within the loop. Free these local objects eagerly
1821 : : * at the end of each iteration.
1822 : : */
967 tgl@sss.pgh.pa.us 1823 : 9805 : pfree(appinfos);
594 rguo@postgresql.org 1824 : 9805 : bms_free(child_relids);
389 1825 : 9805 : free_child_join_sjinfo(child_sjinfo, parent_sjinfo);
1826 : : }
1827 : : }
1828 : :
1829 : : /*
1830 : : * Construct the SpecialJoinInfo for a child-join by translating
1831 : : * SpecialJoinInfo for the join between parents. left_relids and right_relids
1832 : : * are the relids of left and right side of the join respectively.
1833 : : *
1834 : : * If translations are added to or removed from this function, consider
1835 : : * updating free_child_join_sjinfo() accordingly.
1836 : : */
1837 : : static SpecialJoinInfo *
2615 alvherre@alvh.no-ip. 1838 : 9805 : build_child_join_sjinfo(PlannerInfo *root, SpecialJoinInfo *parent_sjinfo,
1839 : : Relids left_relids, Relids right_relids)
1840 : : {
1841 : 9805 : SpecialJoinInfo *sjinfo = makeNode(SpecialJoinInfo);
1842 : : AppendRelInfo **left_appinfos;
1843 : : int left_nappinfos;
1844 : : AppendRelInfo **right_appinfos;
1845 : : int right_nappinfos;
1846 : :
1847 : : /* Dummy SpecialJoinInfos can be created without any translation. */
720 amitlan@postgresql.o 1848 [ + + ]: 9805 : if (parent_sjinfo->jointype == JOIN_INNER)
1849 : : {
1850 [ - + ]: 8212 : Assert(parent_sjinfo->ojrelid == 0);
1851 : 8212 : init_dummy_sjinfo(sjinfo, left_relids, right_relids);
1852 : 8212 : return sjinfo;
1853 : : }
1854 : :
2615 alvherre@alvh.no-ip. 1855 : 1593 : memcpy(sjinfo, parent_sjinfo, sizeof(SpecialJoinInfo));
1856 : 1593 : left_appinfos = find_appinfos_by_relids(root, left_relids,
1857 : : &left_nappinfos);
1858 : 1593 : right_appinfos = find_appinfos_by_relids(root, right_relids,
1859 : : &right_nappinfos);
1860 : :
1861 : 1593 : sjinfo->min_lefthand = adjust_child_relids(sjinfo->min_lefthand,
1862 : : left_nappinfos, left_appinfos);
1863 : 1593 : sjinfo->min_righthand = adjust_child_relids(sjinfo->min_righthand,
1864 : : right_nappinfos,
1865 : : right_appinfos);
1866 : 1593 : sjinfo->syn_lefthand = adjust_child_relids(sjinfo->syn_lefthand,
1867 : : left_nappinfos, left_appinfos);
1868 : 1593 : sjinfo->syn_righthand = adjust_child_relids(sjinfo->syn_righthand,
1869 : : right_nappinfos,
1870 : : right_appinfos);
1871 : : /* outer-join relids need no adjustment */
1872 : 3186 : sjinfo->semi_rhs_exprs = (List *) adjust_appendrel_attrs(root,
1873 : 1593 : (Node *) sjinfo->semi_rhs_exprs,
1874 : : right_nappinfos,
1875 : : right_appinfos);
1876 : :
1877 : 1593 : pfree(left_appinfos);
1878 : 1593 : pfree(right_appinfos);
1879 : :
1880 : 1593 : return sjinfo;
1881 : : }
1882 : :
1883 : : /*
1884 : : * free_child_join_sjinfo
1885 : : * Free memory consumed by a SpecialJoinInfo created by
1886 : : * build_child_join_sjinfo()
1887 : : *
1888 : : * Only members that are translated copies of their counterpart in the parent
1889 : : * SpecialJoinInfo are freed here.
1890 : : */
1891 : : static void
389 rguo@postgresql.org 1892 : 9805 : free_child_join_sjinfo(SpecialJoinInfo *child_sjinfo,
1893 : : SpecialJoinInfo *parent_sjinfo)
1894 : : {
1895 : : /*
1896 : : * Dummy SpecialJoinInfos of inner joins do not have any translated fields
1897 : : * and hence no fields that to be freed.
1898 : : */
1899 [ + + ]: 9805 : if (child_sjinfo->jointype != JOIN_INNER)
1900 : : {
1901 [ + + ]: 1593 : if (child_sjinfo->min_lefthand != parent_sjinfo->min_lefthand)
1902 : 1584 : bms_free(child_sjinfo->min_lefthand);
1903 : :
1904 [ + - ]: 1593 : if (child_sjinfo->min_righthand != parent_sjinfo->min_righthand)
1905 : 1593 : bms_free(child_sjinfo->min_righthand);
1906 : :
1907 [ + - ]: 1593 : if (child_sjinfo->syn_lefthand != parent_sjinfo->syn_lefthand)
1908 : 1593 : bms_free(child_sjinfo->syn_lefthand);
1909 : :
1910 [ + - ]: 1593 : if (child_sjinfo->syn_righthand != parent_sjinfo->syn_righthand)
1911 : 1593 : bms_free(child_sjinfo->syn_righthand);
1912 : :
1913 [ - + ]: 1593 : Assert(child_sjinfo->commute_above_l == parent_sjinfo->commute_above_l);
1914 [ - + ]: 1593 : Assert(child_sjinfo->commute_above_r == parent_sjinfo->commute_above_r);
1915 [ - + ]: 1593 : Assert(child_sjinfo->commute_below_l == parent_sjinfo->commute_below_l);
1916 [ - + ]: 1593 : Assert(child_sjinfo->commute_below_r == parent_sjinfo->commute_below_r);
1917 : :
1918 [ - + ]: 1593 : Assert(child_sjinfo->semi_operators == parent_sjinfo->semi_operators);
1919 : :
1920 : : /*
1921 : : * semi_rhs_exprs may in principle be freed, but a simple pfree() does
1922 : : * not suffice, so we leave it alone.
1923 : : */
1924 : : }
1925 : :
1926 : 9805 : pfree(child_sjinfo);
720 amitlan@postgresql.o 1927 : 9805 : }
1928 : :
1929 : : /*
1930 : : * compute_partition_bounds
1931 : : * Compute the partition bounds for a join rel from those for inputs
1932 : : */
1933 : : static void
2167 efujita@postgresql.o 1934 : 3920 : compute_partition_bounds(PlannerInfo *root, RelOptInfo *rel1,
1935 : : RelOptInfo *rel2, RelOptInfo *joinrel,
1936 : : SpecialJoinInfo *parent_sjinfo,
1937 : : List **parts1, List **parts2)
1938 : : {
1939 : : /*
1940 : : * If we don't have the partition bounds for the join rel yet, try to
1941 : : * compute those along with pairs of partitions to be joined.
1942 : : */
1943 [ + + ]: 3920 : if (joinrel->nparts == -1)
1944 : : {
1945 : 3718 : PartitionScheme part_scheme = joinrel->part_scheme;
1946 : 3718 : PartitionBoundInfo boundinfo = NULL;
1947 : 3718 : int nparts = 0;
1948 : :
1949 [ - + ]: 3718 : Assert(joinrel->boundinfo == NULL);
1950 [ - + ]: 3718 : Assert(joinrel->part_rels == NULL);
1951 : :
1952 : : /*
1953 : : * See if the partition bounds for inputs are exactly the same, in
1954 : : * which case we don't need to work hard: the join rel will have the
1955 : : * same partition bounds as inputs, and the partitions with the same
1956 : : * cardinal positions will form the pairs.
1957 : : *
1958 : : * Note: even in cases where one or both inputs have merged bounds, it
1959 : : * would be possible for both the bounds to be exactly the same, but
1960 : : * it seems unlikely to be worth the cycles to check.
1961 : : */
1962 [ + + ]: 3718 : if (!rel1->partbounds_merged &&
1963 [ + - ]: 3688 : !rel2->partbounds_merged &&
1964 [ + + + + ]: 7246 : rel1->nparts == rel2->nparts &&
1965 : 3558 : partition_bounds_equal(part_scheme->partnatts,
1966 : : part_scheme->parttyplen,
1967 : : part_scheme->parttypbyval,
1968 : : rel1->boundinfo, rel2->boundinfo))
1969 : : {
1970 : 3294 : boundinfo = rel1->boundinfo;
1971 : 3294 : nparts = rel1->nparts;
1972 : : }
1973 : : else
1974 : : {
1975 : : /* Try merging the partition bounds for inputs. */
1976 : 424 : boundinfo = partition_bounds_merge(part_scheme->partnatts,
1977 : 424 : part_scheme->partsupfunc,
1978 : : part_scheme->partcollation,
1979 : : rel1, rel2,
1980 : : parent_sjinfo->jointype,
1981 : : parts1, parts2);
1982 [ + + ]: 424 : if (boundinfo == NULL)
1983 : : {
1984 : 58 : joinrel->nparts = 0;
1985 : 58 : return;
1986 : : }
1987 : 366 : nparts = list_length(*parts1);
1988 : 366 : joinrel->partbounds_merged = true;
1989 : : }
1990 : :
1991 [ - + ]: 3660 : Assert(nparts > 0);
1992 : 3660 : joinrel->boundinfo = boundinfo;
1993 : 3660 : joinrel->nparts = nparts;
95 michael@paquier.xyz 1994 :GNC 3660 : joinrel->part_rels = palloc0_array(RelOptInfo *, nparts);
1995 : : }
1996 : : else
1997 : : {
2167 efujita@postgresql.o 1998 [ - + ]:CBC 202 : Assert(joinrel->nparts > 0);
1999 [ - + ]: 202 : Assert(joinrel->boundinfo);
2000 [ - + ]: 202 : Assert(joinrel->part_rels);
2001 : :
2002 : : /*
2003 : : * If the join rel's partbounds_merged flag is true, it means inputs
2004 : : * are not guaranteed to have the same partition bounds, therefore we
2005 : : * can't assume that the partitions at the same cardinal positions
2006 : : * form the pairs; let get_matching_part_pairs() generate the pairs.
2007 : : * Otherwise, nothing to do since we can assume that.
2008 : : */
2009 [ + + ]: 202 : if (joinrel->partbounds_merged)
2010 : : {
2011 : 18 : get_matching_part_pairs(root, joinrel, rel1, rel2,
2012 : : parts1, parts2);
2013 [ - + ]: 18 : Assert(list_length(*parts1) == joinrel->nparts);
2014 [ - + ]: 18 : Assert(list_length(*parts2) == joinrel->nparts);
2015 : : }
2016 : : }
2017 : : }
2018 : :
2019 : : /*
2020 : : * get_matching_part_pairs
2021 : : * Generate pairs of partitions to be joined from inputs
2022 : : */
2023 : : static void
2024 : 18 : get_matching_part_pairs(PlannerInfo *root, RelOptInfo *joinrel,
2025 : : RelOptInfo *rel1, RelOptInfo *rel2,
2026 : : List **parts1, List **parts2)
2027 : : {
2028 [ + - - + ]: 18 : bool rel1_is_simple = IS_SIMPLE_REL(rel1);
2029 [ - + - - ]: 18 : bool rel2_is_simple = IS_SIMPLE_REL(rel2);
2030 : : int cnt_parts;
2031 : :
2032 : 18 : *parts1 = NIL;
2033 : 18 : *parts2 = NIL;
2034 : :
2035 [ + + ]: 66 : for (cnt_parts = 0; cnt_parts < joinrel->nparts; cnt_parts++)
2036 : : {
2037 : 48 : RelOptInfo *child_joinrel = joinrel->part_rels[cnt_parts];
2038 : : RelOptInfo *child_rel1;
2039 : : RelOptInfo *child_rel2;
2040 : : Relids child_relids1;
2041 : : Relids child_relids2;
2042 : :
2043 : : /*
2044 : : * If this segment of the join is empty, it means that this segment
2045 : : * was ignored when previously creating child-join paths for it in
2046 : : * try_partitionwise_join() as it would not contribute to the join
2047 : : * result, due to one or both inputs being empty; add NULL to each of
2048 : : * the given lists so that this segment will be ignored again in that
2049 : : * function.
2050 : : */
2051 [ - + ]: 48 : if (!child_joinrel)
2052 : : {
2167 efujita@postgresql.o 2053 :UBC 0 : *parts1 = lappend(*parts1, NULL);
2054 : 0 : *parts2 = lappend(*parts2, NULL);
2055 : 0 : continue;
2056 : : }
2057 : :
2058 : : /*
2059 : : * Get a relids set of partition(s) involved in this join segment that
2060 : : * are from the rel1 side.
2061 : : */
2167 efujita@postgresql.o 2062 :CBC 48 : child_relids1 = bms_intersect(child_joinrel->relids,
2063 : 48 : rel1->all_partrels);
2064 [ - + ]: 48 : Assert(bms_num_members(child_relids1) == bms_num_members(rel1->relids));
2065 : :
2066 : : /*
2067 : : * Get a child rel for rel1 with the relids. Note that we should have
2068 : : * the child rel even if rel1 is a join rel, because in that case the
2069 : : * partitions specified in the relids would have matching/overlapping
2070 : : * boundaries, so the specified partitions should be considered as
2071 : : * ones to be joined when planning partitionwise joins of rel1,
2072 : : * meaning that the child rel would have been built by the time we get
2073 : : * here.
2074 : : */
2075 [ - + ]: 48 : if (rel1_is_simple)
2076 : : {
2167 efujita@postgresql.o 2077 :UBC 0 : int varno = bms_singleton_member(child_relids1);
2078 : :
2079 : 0 : child_rel1 = find_base_rel(root, varno);
2080 : : }
2081 : : else
2167 efujita@postgresql.o 2082 :CBC 48 : child_rel1 = find_join_rel(root, child_relids1);
2083 [ - + ]: 48 : Assert(child_rel1);
2084 : :
2085 : : /*
2086 : : * Get a relids set of partition(s) involved in this join segment that
2087 : : * are from the rel2 side.
2088 : : */
2089 : 48 : child_relids2 = bms_intersect(child_joinrel->relids,
2090 : 48 : rel2->all_partrels);
2091 [ - + ]: 48 : Assert(bms_num_members(child_relids2) == bms_num_members(rel2->relids));
2092 : :
2093 : : /*
2094 : : * Get a child rel for rel2 with the relids. See above comments.
2095 : : */
2096 [ + - ]: 48 : if (rel2_is_simple)
2097 : : {
2098 : 48 : int varno = bms_singleton_member(child_relids2);
2099 : :
2100 : 48 : child_rel2 = find_base_rel(root, varno);
2101 : : }
2102 : : else
2167 efujita@postgresql.o 2103 :UBC 0 : child_rel2 = find_join_rel(root, child_relids2);
2167 efujita@postgresql.o 2104 [ - + ]:CBC 48 : Assert(child_rel2);
2105 : :
2106 : : /*
2107 : : * The join of rel1 and rel2 is legal, so is the join of the child
2108 : : * rels obtained above; add them to the given lists as a join pair
2109 : : * producing this join segment.
2110 : : */
2111 : 48 : *parts1 = lappend(*parts1, child_rel1);
2112 : 48 : *parts2 = lappend(*parts2, child_rel2);
2113 : : }
2114 : 18 : }
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