Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * allpaths.c
4 : * Routines to find possible search paths for processing a query
5 : *
6 : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : *
10 : * IDENTIFICATION
11 : * src/backend/optimizer/path/allpaths.c
12 : *
13 : *-------------------------------------------------------------------------
14 : */
15 :
16 : #include "postgres.h"
17 :
18 : #include <limits.h>
19 : #include <math.h>
20 :
21 : #include "access/sysattr.h"
22 : #include "access/tsmapi.h"
23 : #include "catalog/pg_class.h"
24 : #include "catalog/pg_operator.h"
25 : #include "catalog/pg_proc.h"
26 : #include "foreign/fdwapi.h"
27 : #include "miscadmin.h"
28 : #include "nodes/makefuncs.h"
29 : #include "nodes/nodeFuncs.h"
30 : #include "nodes/supportnodes.h"
31 : #ifdef OPTIMIZER_DEBUG
32 : #include "nodes/print.h"
33 : #endif
34 : #include "optimizer/appendinfo.h"
35 : #include "optimizer/clauses.h"
36 : #include "optimizer/cost.h"
37 : #include "optimizer/geqo.h"
38 : #include "optimizer/optimizer.h"
39 : #include "optimizer/pathnode.h"
40 : #include "optimizer/paths.h"
41 : #include "optimizer/plancat.h"
42 : #include "optimizer/planner.h"
43 : #include "optimizer/prep.h"
44 : #include "optimizer/tlist.h"
45 : #include "parser/parse_clause.h"
46 : #include "parser/parsetree.h"
47 : #include "partitioning/partbounds.h"
48 : #include "port/pg_bitutils.h"
49 : #include "rewrite/rewriteManip.h"
50 : #include "utils/lsyscache.h"
51 : #include "utils/selfuncs.h"
52 :
53 :
54 : /* Bitmask flags for pushdown_safety_info.unsafeFlags */
55 : #define UNSAFE_HAS_VOLATILE_FUNC (1 << 0)
56 : #define UNSAFE_HAS_SET_FUNC (1 << 1)
57 : #define UNSAFE_NOTIN_DISTINCTON_CLAUSE (1 << 2)
58 : #define UNSAFE_NOTIN_PARTITIONBY_CLAUSE (1 << 3)
59 : #define UNSAFE_TYPE_MISMATCH (1 << 4)
60 :
61 : /* results of subquery_is_pushdown_safe */
62 : typedef struct pushdown_safety_info
63 : {
64 : unsigned char *unsafeFlags; /* bitmask of reasons why this target list
65 : * column is unsafe for qual pushdown, or 0 if
66 : * no reason. */
67 : bool unsafeVolatile; /* don't push down volatile quals */
68 : bool unsafeLeaky; /* don't push down leaky quals */
69 : } pushdown_safety_info;
70 :
71 : /* Return type for qual_is_pushdown_safe */
72 : typedef enum pushdown_safe_type
73 : {
74 : PUSHDOWN_UNSAFE, /* unsafe to push qual into subquery */
75 : PUSHDOWN_SAFE, /* safe to push qual into subquery */
76 : PUSHDOWN_WINDOWCLAUSE_RUNCOND, /* unsafe, but may work as WindowClause
77 : * run condition */
78 : } pushdown_safe_type;
79 :
80 : /* These parameters are set by GUC */
81 : bool enable_geqo = false; /* just in case GUC doesn't set it */
82 : bool enable_eager_aggregate = true;
83 : int geqo_threshold;
84 : double min_eager_agg_group_size;
85 : int min_parallel_table_scan_size;
86 : int min_parallel_index_scan_size;
87 :
88 : /* Hook for plugins to get control in set_rel_pathlist() */
89 : set_rel_pathlist_hook_type set_rel_pathlist_hook = NULL;
90 :
91 : /* Hook for plugins to replace standard_join_search() */
92 : join_search_hook_type join_search_hook = NULL;
93 :
94 :
95 : static void set_base_rel_consider_startup(PlannerInfo *root);
96 : static void set_base_rel_sizes(PlannerInfo *root);
97 : static void setup_simple_grouped_rels(PlannerInfo *root);
98 : static void set_base_rel_pathlists(PlannerInfo *root);
99 : static void set_rel_size(PlannerInfo *root, RelOptInfo *rel,
100 : Index rti, RangeTblEntry *rte);
101 : static void set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
102 : Index rti, RangeTblEntry *rte);
103 : static void set_plain_rel_size(PlannerInfo *root, RelOptInfo *rel,
104 : RangeTblEntry *rte);
105 : static void create_plain_partial_paths(PlannerInfo *root, RelOptInfo *rel);
106 : static void set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
107 : RangeTblEntry *rte);
108 : static void set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
109 : RangeTblEntry *rte);
110 : static void set_tablesample_rel_size(PlannerInfo *root, RelOptInfo *rel,
111 : RangeTblEntry *rte);
112 : static void set_tablesample_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
113 : RangeTblEntry *rte);
114 : static void set_foreign_size(PlannerInfo *root, RelOptInfo *rel,
115 : RangeTblEntry *rte);
116 : static void set_foreign_pathlist(PlannerInfo *root, RelOptInfo *rel,
117 : RangeTblEntry *rte);
118 : static void set_append_rel_size(PlannerInfo *root, RelOptInfo *rel,
119 : Index rti, RangeTblEntry *rte);
120 : static void set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
121 : Index rti, RangeTblEntry *rte);
122 : static void set_grouped_rel_pathlist(PlannerInfo *root, RelOptInfo *rel);
123 : static void generate_orderedappend_paths(PlannerInfo *root, RelOptInfo *rel,
124 : List *live_childrels,
125 : List *all_child_pathkeys);
126 : static Path *get_cheapest_parameterized_child_path(PlannerInfo *root,
127 : RelOptInfo *rel,
128 : Relids required_outer);
129 : static void accumulate_append_subpath(Path *path,
130 : List **subpaths,
131 : List **special_subpaths);
132 : static Path *get_singleton_append_subpath(Path *path);
133 : static void set_dummy_rel_pathlist(RelOptInfo *rel);
134 : static void set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
135 : Index rti, RangeTblEntry *rte);
136 : static void set_function_pathlist(PlannerInfo *root, RelOptInfo *rel,
137 : RangeTblEntry *rte);
138 : static void set_values_pathlist(PlannerInfo *root, RelOptInfo *rel,
139 : RangeTblEntry *rte);
140 : static void set_tablefunc_pathlist(PlannerInfo *root, RelOptInfo *rel,
141 : RangeTblEntry *rte);
142 : static void set_cte_pathlist(PlannerInfo *root, RelOptInfo *rel,
143 : RangeTblEntry *rte);
144 : static void set_namedtuplestore_pathlist(PlannerInfo *root, RelOptInfo *rel,
145 : RangeTblEntry *rte);
146 : static void set_result_pathlist(PlannerInfo *root, RelOptInfo *rel,
147 : RangeTblEntry *rte);
148 : static void set_worktable_pathlist(PlannerInfo *root, RelOptInfo *rel,
149 : RangeTblEntry *rte);
150 : static RelOptInfo *make_rel_from_joinlist(PlannerInfo *root, List *joinlist);
151 : static bool subquery_is_pushdown_safe(Query *subquery, Query *topquery,
152 : pushdown_safety_info *safetyInfo);
153 : static bool recurse_pushdown_safe(Node *setOp, Query *topquery,
154 : pushdown_safety_info *safetyInfo);
155 : static void check_output_expressions(Query *subquery,
156 : pushdown_safety_info *safetyInfo);
157 : static void compare_tlist_datatypes(List *tlist, List *colTypes,
158 : pushdown_safety_info *safetyInfo);
159 : static bool targetIsInAllPartitionLists(TargetEntry *tle, Query *query);
160 : static pushdown_safe_type qual_is_pushdown_safe(Query *subquery, Index rti,
161 : RestrictInfo *rinfo,
162 : pushdown_safety_info *safetyInfo);
163 : static void subquery_push_qual(Query *subquery,
164 : RangeTblEntry *rte, Index rti, Node *qual);
165 : static void recurse_push_qual(Node *setOp, Query *topquery,
166 : RangeTblEntry *rte, Index rti, Node *qual);
167 : static void remove_unused_subquery_outputs(Query *subquery, RelOptInfo *rel,
168 : Bitmapset *extra_used_attrs);
169 :
170 :
171 : /*
172 : * make_one_rel
173 : * Finds all possible access paths for executing a query, returning a
174 : * single rel that represents the join of all base rels in the query.
175 : */
176 : RelOptInfo *
177 326656 : make_one_rel(PlannerInfo *root, List *joinlist)
178 : {
179 : RelOptInfo *rel;
180 : Index rti;
181 : double total_pages;
182 :
183 : /* Mark base rels as to whether we care about fast-start plans */
184 326656 : set_base_rel_consider_startup(root);
185 :
186 : /*
187 : * Compute size estimates and consider_parallel flags for each base rel.
188 : */
189 326656 : set_base_rel_sizes(root);
190 :
191 : /*
192 : * Build grouped relations for simple rels (i.e., base or "other" member
193 : * relations) where possible.
194 : */
195 326622 : setup_simple_grouped_rels(root);
196 :
197 : /*
198 : * We should now have size estimates for every actual table involved in
199 : * the query, and we also know which if any have been deleted from the
200 : * query by join removal, pruned by partition pruning, or eliminated by
201 : * constraint exclusion. So we can now compute total_table_pages.
202 : *
203 : * Note that appendrels are not double-counted here, even though we don't
204 : * bother to distinguish RelOptInfos for appendrel parents, because the
205 : * parents will have pages = 0.
206 : *
207 : * XXX if a table is self-joined, we will count it once per appearance,
208 : * which perhaps is the wrong thing ... but that's not completely clear,
209 : * and detecting self-joins here is difficult, so ignore it for now.
210 : */
211 326622 : total_pages = 0;
212 1011982 : for (rti = 1; rti < root->simple_rel_array_size; rti++)
213 : {
214 685360 : RelOptInfo *brel = root->simple_rel_array[rti];
215 :
216 : /* there may be empty slots corresponding to non-baserel RTEs */
217 685360 : if (brel == NULL)
218 162100 : continue;
219 :
220 : Assert(brel->relid == rti); /* sanity check on array */
221 :
222 523260 : if (IS_DUMMY_REL(brel))
223 1394 : continue;
224 :
225 521866 : if (IS_SIMPLE_REL(brel))
226 521866 : total_pages += (double) brel->pages;
227 : }
228 326622 : root->total_table_pages = total_pages;
229 :
230 : /*
231 : * Generate access paths for each base rel.
232 : */
233 326622 : set_base_rel_pathlists(root);
234 :
235 : /*
236 : * Generate access paths for the entire join tree.
237 : */
238 326622 : rel = make_rel_from_joinlist(root, joinlist);
239 :
240 : /*
241 : * The result should join all and only the query's base + outer-join rels.
242 : */
243 : Assert(bms_equal(rel->relids, root->all_query_rels));
244 :
245 326622 : return rel;
246 : }
247 :
248 : /*
249 : * set_base_rel_consider_startup
250 : * Set the consider_[param_]startup flags for each base-relation entry.
251 : *
252 : * For the moment, we only deal with consider_param_startup here; because the
253 : * logic for consider_startup is pretty trivial and is the same for every base
254 : * relation, we just let build_simple_rel() initialize that flag correctly to
255 : * start with. If that logic ever gets more complicated it would probably
256 : * be better to move it here.
257 : */
258 : static void
259 326656 : set_base_rel_consider_startup(PlannerInfo *root)
260 : {
261 : /*
262 : * Since parameterized paths can only be used on the inside of a nestloop
263 : * join plan, there is usually little value in considering fast-start
264 : * plans for them. However, for relations that are on the RHS of a SEMI
265 : * or ANTI join, a fast-start plan can be useful because we're only going
266 : * to care about fetching one tuple anyway.
267 : *
268 : * To minimize growth of planning time, we currently restrict this to
269 : * cases where the RHS is a single base relation, not a join; there is no
270 : * provision for consider_param_startup to get set at all on joinrels.
271 : * Also we don't worry about appendrels. costsize.c's costing rules for
272 : * nestloop semi/antijoins don't consider such cases either.
273 : */
274 : ListCell *lc;
275 :
276 369088 : foreach(lc, root->join_info_list)
277 : {
278 42432 : SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(lc);
279 : int varno;
280 :
281 50956 : if ((sjinfo->jointype == JOIN_SEMI || sjinfo->jointype == JOIN_ANTI) &&
282 8524 : bms_get_singleton_member(sjinfo->syn_righthand, &varno))
283 : {
284 8324 : RelOptInfo *rel = find_base_rel(root, varno);
285 :
286 8324 : rel->consider_param_startup = true;
287 : }
288 : }
289 326656 : }
290 :
291 : /*
292 : * set_base_rel_sizes
293 : * Set the size estimates (rows and widths) for each base-relation entry.
294 : * Also determine whether to consider parallel paths for base relations.
295 : *
296 : * We do this in a separate pass over the base rels so that rowcount
297 : * estimates are available for parameterized path generation, and also so
298 : * that each rel's consider_parallel flag is set correctly before we begin to
299 : * generate paths.
300 : */
301 : static void
302 326656 : set_base_rel_sizes(PlannerInfo *root)
303 : {
304 : Index rti;
305 :
306 1012018 : for (rti = 1; rti < root->simple_rel_array_size; rti++)
307 : {
308 685396 : RelOptInfo *rel = root->simple_rel_array[rti];
309 : RangeTblEntry *rte;
310 :
311 : /* there may be empty slots corresponding to non-baserel RTEs */
312 685396 : if (rel == NULL)
313 162102 : continue;
314 :
315 : Assert(rel->relid == rti); /* sanity check on array */
316 :
317 : /* ignore RTEs that are "other rels" */
318 523294 : if (rel->reloptkind != RELOPT_BASEREL)
319 58080 : continue;
320 :
321 465214 : rte = root->simple_rte_array[rti];
322 :
323 : /*
324 : * If parallelism is allowable for this query in general, see whether
325 : * it's allowable for this rel in particular. We have to do this
326 : * before set_rel_size(), because (a) if this rel is an inheritance
327 : * parent, set_append_rel_size() will use and perhaps change the rel's
328 : * consider_parallel flag, and (b) for some RTE types, set_rel_size()
329 : * goes ahead and makes paths immediately.
330 : */
331 465214 : if (root->glob->parallelModeOK)
332 371264 : set_rel_consider_parallel(root, rel, rte);
333 :
334 465214 : set_rel_size(root, rel, rti, rte);
335 : }
336 326622 : }
337 :
338 : /*
339 : * setup_simple_grouped_rels
340 : * For each simple relation, build a grouped simple relation if eager
341 : * aggregation is possible and if this relation can produce grouped paths.
342 : */
343 : static void
344 326622 : setup_simple_grouped_rels(PlannerInfo *root)
345 : {
346 : Index rti;
347 :
348 : /*
349 : * If there are no aggregate expressions or grouping expressions, eager
350 : * aggregation is not possible.
351 : */
352 326622 : if (root->agg_clause_list == NIL ||
353 658 : root->group_expr_list == NIL)
354 326030 : return;
355 :
356 5074 : for (rti = 1; rti < root->simple_rel_array_size; rti++)
357 : {
358 4482 : RelOptInfo *rel = root->simple_rel_array[rti];
359 :
360 : /* there may be empty slots corresponding to non-baserel RTEs */
361 4482 : if (rel == NULL)
362 1414 : continue;
363 :
364 : Assert(rel->relid == rti); /* sanity check on array */
365 : Assert(IS_SIMPLE_REL(rel)); /* sanity check on rel */
366 :
367 3068 : (void) build_simple_grouped_rel(root, rel);
368 : }
369 : }
370 :
371 : /*
372 : * set_base_rel_pathlists
373 : * Finds all paths available for scanning each base-relation entry.
374 : * Sequential scan and any available indices are considered.
375 : * Each useful path is attached to its relation's 'pathlist' field.
376 : */
377 : static void
378 326622 : set_base_rel_pathlists(PlannerInfo *root)
379 : {
380 : Index rti;
381 :
382 1011982 : for (rti = 1; rti < root->simple_rel_array_size; rti++)
383 : {
384 685360 : RelOptInfo *rel = root->simple_rel_array[rti];
385 :
386 : /* there may be empty slots corresponding to non-baserel RTEs */
387 685360 : if (rel == NULL)
388 162100 : continue;
389 :
390 : Assert(rel->relid == rti); /* sanity check on array */
391 :
392 : /* ignore RTEs that are "other rels" */
393 523260 : if (rel->reloptkind != RELOPT_BASEREL)
394 58080 : continue;
395 :
396 465180 : set_rel_pathlist(root, rel, rti, root->simple_rte_array[rti]);
397 : }
398 326622 : }
399 :
400 : /*
401 : * set_rel_size
402 : * Set size estimates for a base relation
403 : */
404 : static void
405 522984 : set_rel_size(PlannerInfo *root, RelOptInfo *rel,
406 : Index rti, RangeTblEntry *rte)
407 : {
408 988198 : if (rel->reloptkind == RELOPT_BASEREL &&
409 465214 : relation_excluded_by_constraints(root, rel, rte))
410 : {
411 : /*
412 : * We proved we don't need to scan the rel via constraint exclusion,
413 : * so set up a single dummy path for it. Here we only check this for
414 : * regular baserels; if it's an otherrel, CE was already checked in
415 : * set_append_rel_size().
416 : *
417 : * In this case, we go ahead and set up the relation's path right away
418 : * instead of leaving it for set_rel_pathlist to do. This is because
419 : * we don't have a convention for marking a rel as dummy except by
420 : * assigning a dummy path to it.
421 : */
422 658 : set_dummy_rel_pathlist(rel);
423 : }
424 522326 : else if (rte->inh)
425 : {
426 : /* It's an "append relation", process accordingly */
427 25692 : set_append_rel_size(root, rel, rti, rte);
428 : }
429 : else
430 : {
431 496634 : switch (rel->rtekind)
432 : {
433 408522 : case RTE_RELATION:
434 408522 : if (rte->relkind == RELKIND_FOREIGN_TABLE)
435 : {
436 : /* Foreign table */
437 2462 : set_foreign_size(root, rel, rte);
438 : }
439 406060 : else if (rte->relkind == RELKIND_PARTITIONED_TABLE)
440 : {
441 : /*
442 : * We could get here if asked to scan a partitioned table
443 : * with ONLY. In that case we shouldn't scan any of the
444 : * partitions, so mark it as a dummy rel.
445 : */
446 40 : set_dummy_rel_pathlist(rel);
447 : }
448 406020 : else if (rte->tablesample != NULL)
449 : {
450 : /* Sampled relation */
451 306 : set_tablesample_rel_size(root, rel, rte);
452 : }
453 : else
454 : {
455 : /* Plain relation */
456 405714 : set_plain_rel_size(root, rel, rte);
457 : }
458 408488 : break;
459 17532 : case RTE_SUBQUERY:
460 :
461 : /*
462 : * Subqueries don't support making a choice between
463 : * parameterized and unparameterized paths, so just go ahead
464 : * and build their paths immediately.
465 : */
466 17532 : set_subquery_pathlist(root, rel, rti, rte);
467 17532 : break;
468 51798 : case RTE_FUNCTION:
469 51798 : set_function_size_estimates(root, rel);
470 51798 : break;
471 626 : case RTE_TABLEFUNC:
472 626 : set_tablefunc_size_estimates(root, rel);
473 626 : break;
474 8294 : case RTE_VALUES:
475 8294 : set_values_size_estimates(root, rel);
476 8294 : break;
477 5176 : case RTE_CTE:
478 :
479 : /*
480 : * CTEs don't support making a choice between parameterized
481 : * and unparameterized paths, so just go ahead and build their
482 : * paths immediately.
483 : */
484 5176 : if (rte->self_reference)
485 934 : set_worktable_pathlist(root, rel, rte);
486 : else
487 4242 : set_cte_pathlist(root, rel, rte);
488 5176 : break;
489 478 : case RTE_NAMEDTUPLESTORE:
490 : /* Might as well just build the path immediately */
491 478 : set_namedtuplestore_pathlist(root, rel, rte);
492 478 : break;
493 4208 : case RTE_RESULT:
494 : /* Might as well just build the path immediately */
495 4208 : set_result_pathlist(root, rel, rte);
496 4208 : break;
497 0 : default:
498 0 : elog(ERROR, "unexpected rtekind: %d", (int) rel->rtekind);
499 : break;
500 : }
501 : }
502 :
503 : /*
504 : * We insist that all non-dummy rels have a nonzero rowcount estimate.
505 : */
506 : Assert(rel->rows > 0 || IS_DUMMY_REL(rel));
507 522948 : }
508 :
509 : /*
510 : * set_rel_pathlist
511 : * Build access paths for a base relation
512 : */
513 : static void
514 523086 : set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
515 : Index rti, RangeTblEntry *rte)
516 : {
517 523086 : if (IS_DUMMY_REL(rel))
518 : {
519 : /* We already proved the relation empty, so nothing more to do */
520 : }
521 521830 : else if (rte->inh)
522 : {
523 : /* It's an "append relation", process accordingly */
524 25396 : set_append_rel_pathlist(root, rel, rti, rte);
525 : }
526 : else
527 : {
528 496434 : switch (rel->rtekind)
529 : {
530 408448 : case RTE_RELATION:
531 408448 : if (rte->relkind == RELKIND_FOREIGN_TABLE)
532 : {
533 : /* Foreign table */
534 2458 : set_foreign_pathlist(root, rel, rte);
535 : }
536 405990 : else if (rte->tablesample != NULL)
537 : {
538 : /* Sampled relation */
539 306 : set_tablesample_rel_pathlist(root, rel, rte);
540 : }
541 : else
542 : {
543 : /* Plain relation */
544 405684 : set_plain_rel_pathlist(root, rel, rte);
545 : }
546 408448 : break;
547 17406 : case RTE_SUBQUERY:
548 : /* Subquery --- fully handled during set_rel_size */
549 17406 : break;
550 51798 : case RTE_FUNCTION:
551 : /* RangeFunction */
552 51798 : set_function_pathlist(root, rel, rte);
553 51798 : break;
554 626 : case RTE_TABLEFUNC:
555 : /* Table Function */
556 626 : set_tablefunc_pathlist(root, rel, rte);
557 626 : break;
558 8294 : case RTE_VALUES:
559 : /* Values list */
560 8294 : set_values_pathlist(root, rel, rte);
561 8294 : break;
562 5176 : case RTE_CTE:
563 : /* CTE reference --- fully handled during set_rel_size */
564 5176 : break;
565 478 : case RTE_NAMEDTUPLESTORE:
566 : /* tuplestore reference --- fully handled during set_rel_size */
567 478 : break;
568 4208 : case RTE_RESULT:
569 : /* simple Result --- fully handled during set_rel_size */
570 4208 : break;
571 0 : default:
572 0 : elog(ERROR, "unexpected rtekind: %d", (int) rel->rtekind);
573 : break;
574 : }
575 : }
576 :
577 : /*
578 : * Allow a plugin to editorialize on the set of Paths for this base
579 : * relation. It could add new paths (such as CustomPaths) by calling
580 : * add_path(), or add_partial_path() if parallel aware. It could also
581 : * delete or modify paths added by the core code.
582 : */
583 523086 : if (set_rel_pathlist_hook)
584 0 : (*set_rel_pathlist_hook) (root, rel, rti, rte);
585 :
586 : /*
587 : * If this is a baserel, we should normally consider gathering any partial
588 : * paths we may have created for it. We have to do this after calling the
589 : * set_rel_pathlist_hook, else it cannot add partial paths to be included
590 : * here.
591 : *
592 : * However, if this is an inheritance child, skip it. Otherwise, we could
593 : * end up with a very large number of gather nodes, each trying to grab
594 : * its own pool of workers. Instead, we'll consider gathering partial
595 : * paths for the parent appendrel.
596 : *
597 : * Also, if this is the topmost scan/join rel, we postpone gathering until
598 : * the final scan/join targetlist is available (see grouping_planner).
599 : */
600 523086 : if (rel->reloptkind == RELOPT_BASEREL &&
601 465180 : !bms_equal(rel->relids, root->all_query_rels))
602 239048 : generate_useful_gather_paths(root, rel, false);
603 :
604 : /* Now find the cheapest of the paths for this rel */
605 523086 : set_cheapest(rel);
606 :
607 : /*
608 : * If a grouped relation for this rel exists, build partial aggregation
609 : * paths for it.
610 : *
611 : * Note that this can only happen after we've called set_cheapest() for
612 : * this base rel, because we need its cheapest paths.
613 : */
614 523086 : set_grouped_rel_pathlist(root, rel);
615 :
616 : #ifdef OPTIMIZER_DEBUG
617 : pprint(rel);
618 : #endif
619 523086 : }
620 :
621 : /*
622 : * set_plain_rel_size
623 : * Set size estimates for a plain relation (no subquery, no inheritance)
624 : */
625 : static void
626 405714 : set_plain_rel_size(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
627 : {
628 : /*
629 : * Test any partial indexes of rel for applicability. We must do this
630 : * first since partial unique indexes can affect size estimates.
631 : */
632 405714 : check_index_predicates(root, rel);
633 :
634 : /* Mark rel with estimated output rows, width, etc */
635 405714 : set_baserel_size_estimates(root, rel);
636 405684 : }
637 :
638 : /*
639 : * If this relation could possibly be scanned from within a worker, then set
640 : * its consider_parallel flag.
641 : */
642 : static void
643 414424 : set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
644 : RangeTblEntry *rte)
645 : {
646 : /*
647 : * The flag has previously been initialized to false, so we can just
648 : * return if it becomes clear that we can't safely set it.
649 : */
650 : Assert(!rel->consider_parallel);
651 :
652 : /* Don't call this if parallelism is disallowed for the entire query. */
653 : Assert(root->glob->parallelModeOK);
654 :
655 : /* This should only be called for baserels and appendrel children. */
656 : Assert(IS_SIMPLE_REL(rel));
657 :
658 : /* Assorted checks based on rtekind. */
659 414424 : switch (rte->rtekind)
660 : {
661 355202 : case RTE_RELATION:
662 :
663 : /*
664 : * Currently, parallel workers can't access the leader's temporary
665 : * tables. We could possibly relax this if we wrote all of its
666 : * local buffers at the start of the query and made no changes
667 : * thereafter (maybe we could allow hint bit changes), and if we
668 : * taught the workers to read them. Writing a large number of
669 : * temporary buffers could be expensive, though, and we don't have
670 : * the rest of the necessary infrastructure right now anyway. So
671 : * for now, bail out if we see a temporary table.
672 : */
673 355202 : if (get_rel_persistence(rte->relid) == RELPERSISTENCE_TEMP)
674 8540 : return;
675 :
676 : /*
677 : * Table sampling can be pushed down to workers if the sample
678 : * function and its arguments are safe.
679 : */
680 346662 : if (rte->tablesample != NULL)
681 : {
682 330 : char proparallel = func_parallel(rte->tablesample->tsmhandler);
683 :
684 330 : if (proparallel != PROPARALLEL_SAFE)
685 36 : return;
686 294 : if (!is_parallel_safe(root, (Node *) rte->tablesample->args))
687 12 : return;
688 : }
689 :
690 : /*
691 : * Ask FDWs whether they can support performing a ForeignScan
692 : * within a worker. Most often, the answer will be no. For
693 : * example, if the nature of the FDW is such that it opens a TCP
694 : * connection with a remote server, each parallel worker would end
695 : * up with a separate connection, and these connections might not
696 : * be appropriately coordinated between workers and the leader.
697 : */
698 346614 : if (rte->relkind == RELKIND_FOREIGN_TABLE)
699 : {
700 : Assert(rel->fdwroutine);
701 1552 : if (!rel->fdwroutine->IsForeignScanParallelSafe)
702 1480 : return;
703 72 : if (!rel->fdwroutine->IsForeignScanParallelSafe(root, rel, rte))
704 0 : return;
705 : }
706 :
707 : /*
708 : * There are additional considerations for appendrels, which we'll
709 : * deal with in set_append_rel_size and set_append_rel_pathlist.
710 : * For now, just set consider_parallel based on the rel's own
711 : * quals and targetlist.
712 : */
713 345134 : break;
714 :
715 19278 : case RTE_SUBQUERY:
716 :
717 : /*
718 : * There's no intrinsic problem with scanning a subquery-in-FROM
719 : * (as distinct from a SubPlan or InitPlan) in a parallel worker.
720 : * If the subquery doesn't happen to have any parallel-safe paths,
721 : * then flagging it as consider_parallel won't change anything,
722 : * but that's true for plain tables, too. We must set
723 : * consider_parallel based on the rel's own quals and targetlist,
724 : * so that if a subquery path is parallel-safe but the quals and
725 : * projection we're sticking onto it are not, we correctly mark
726 : * the SubqueryScanPath as not parallel-safe. (Note that
727 : * set_subquery_pathlist() might push some of these quals down
728 : * into the subquery itself, but that doesn't change anything.)
729 : *
730 : * We can't push sub-select containing LIMIT/OFFSET to workers as
731 : * there is no guarantee that the row order will be fully
732 : * deterministic, and applying LIMIT/OFFSET will lead to
733 : * inconsistent results at the top-level. (In some cases, where
734 : * the result is ordered, we could relax this restriction. But it
735 : * doesn't currently seem worth expending extra effort to do so.)
736 : */
737 : {
738 19278 : Query *subquery = castNode(Query, rte->subquery);
739 :
740 19278 : if (limit_needed(subquery))
741 508 : return;
742 : }
743 18770 : break;
744 :
745 0 : case RTE_JOIN:
746 : /* Shouldn't happen; we're only considering baserels here. */
747 : Assert(false);
748 0 : return;
749 :
750 28044 : case RTE_FUNCTION:
751 : /* Check for parallel-restricted functions. */
752 28044 : if (!is_parallel_safe(root, (Node *) rte->functions))
753 12800 : return;
754 15244 : break;
755 :
756 626 : case RTE_TABLEFUNC:
757 : /* not parallel safe */
758 626 : return;
759 :
760 2844 : case RTE_VALUES:
761 : /* Check for parallel-restricted functions. */
762 2844 : if (!is_parallel_safe(root, (Node *) rte->values_lists))
763 12 : return;
764 2832 : break;
765 :
766 4214 : case RTE_CTE:
767 :
768 : /*
769 : * CTE tuplestores aren't shared among parallel workers, so we
770 : * force all CTE scans to happen in the leader. Also, populating
771 : * the CTE would require executing a subplan that's not available
772 : * in the worker, might be parallel-restricted, and must get
773 : * executed only once.
774 : */
775 4214 : return;
776 :
777 450 : case RTE_NAMEDTUPLESTORE:
778 :
779 : /*
780 : * tuplestore cannot be shared, at least without more
781 : * infrastructure to support that.
782 : */
783 450 : return;
784 :
785 3766 : case RTE_RESULT:
786 : /* RESULT RTEs, in themselves, are no problem. */
787 3766 : break;
788 0 : case RTE_GROUP:
789 : /* Shouldn't happen; we're only considering baserels here. */
790 : Assert(false);
791 0 : return;
792 : }
793 :
794 : /*
795 : * If there's anything in baserestrictinfo that's parallel-restricted, we
796 : * give up on parallelizing access to this relation. We could consider
797 : * instead postponing application of the restricted quals until we're
798 : * above all the parallelism in the plan tree, but it's not clear that
799 : * that would be a win in very many cases, and it might be tricky to make
800 : * outer join clauses work correctly. It would likely break equivalence
801 : * classes, too.
802 : */
803 385746 : if (!is_parallel_safe(root, (Node *) rel->baserestrictinfo))
804 27162 : return;
805 :
806 : /*
807 : * Likewise, if the relation's outputs are not parallel-safe, give up.
808 : * (Usually, they're just Vars, but sometimes they're not.)
809 : */
810 358584 : if (!is_parallel_safe(root, (Node *) rel->reltarget->exprs))
811 18 : return;
812 :
813 : /* We have a winner. */
814 358566 : rel->consider_parallel = true;
815 : }
816 :
817 : /*
818 : * set_plain_rel_pathlist
819 : * Build access paths for a plain relation (no subquery, no inheritance)
820 : */
821 : static void
822 405684 : set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
823 : {
824 : Relids required_outer;
825 :
826 : /*
827 : * We don't support pushing join clauses into the quals of a seqscan, but
828 : * it could still have required parameterization due to LATERAL refs in
829 : * its tlist.
830 : */
831 405684 : required_outer = rel->lateral_relids;
832 :
833 : /*
834 : * Consider TID scans.
835 : *
836 : * If create_tidscan_paths returns true, then a TID scan path is forced.
837 : * This happens when rel->baserestrictinfo contains CurrentOfExpr, because
838 : * the executor can't handle any other type of path for such queries.
839 : * Hence, we return without adding any other paths.
840 : */
841 405684 : if (create_tidscan_paths(root, rel))
842 404 : return;
843 :
844 : /* Consider sequential scan */
845 405280 : add_path(rel, create_seqscan_path(root, rel, required_outer, 0));
846 :
847 : /* If appropriate, consider parallel sequential scan */
848 405280 : if (rel->consider_parallel && required_outer == NULL)
849 304294 : create_plain_partial_paths(root, rel);
850 :
851 : /* Consider index scans */
852 405280 : create_index_paths(root, rel);
853 : }
854 :
855 : /*
856 : * create_plain_partial_paths
857 : * Build partial access paths for parallel scan of a plain relation
858 : */
859 : static void
860 304294 : create_plain_partial_paths(PlannerInfo *root, RelOptInfo *rel)
861 : {
862 : int parallel_workers;
863 :
864 304294 : parallel_workers = compute_parallel_worker(rel, rel->pages, -1,
865 : max_parallel_workers_per_gather);
866 :
867 : /* If any limit was set to zero, the user doesn't want a parallel scan. */
868 304294 : if (parallel_workers <= 0)
869 276842 : return;
870 :
871 : /* Add an unordered partial path based on a parallel sequential scan. */
872 27452 : add_partial_path(rel, create_seqscan_path(root, rel, NULL, parallel_workers));
873 : }
874 :
875 : /*
876 : * set_tablesample_rel_size
877 : * Set size estimates for a sampled relation
878 : */
879 : static void
880 306 : set_tablesample_rel_size(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
881 : {
882 306 : TableSampleClause *tsc = rte->tablesample;
883 : TsmRoutine *tsm;
884 : BlockNumber pages;
885 : double tuples;
886 :
887 : /*
888 : * Test any partial indexes of rel for applicability. We must do this
889 : * first since partial unique indexes can affect size estimates.
890 : */
891 306 : check_index_predicates(root, rel);
892 :
893 : /*
894 : * Call the sampling method's estimation function to estimate the number
895 : * of pages it will read and the number of tuples it will return. (Note:
896 : * we assume the function returns sane values.)
897 : */
898 306 : tsm = GetTsmRoutine(tsc->tsmhandler);
899 306 : tsm->SampleScanGetSampleSize(root, rel, tsc->args,
900 : &pages, &tuples);
901 :
902 : /*
903 : * For the moment, because we will only consider a SampleScan path for the
904 : * rel, it's okay to just overwrite the pages and tuples estimates for the
905 : * whole relation. If we ever consider multiple path types for sampled
906 : * rels, we'll need more complication.
907 : */
908 306 : rel->pages = pages;
909 306 : rel->tuples = tuples;
910 :
911 : /* Mark rel with estimated output rows, width, etc */
912 306 : set_baserel_size_estimates(root, rel);
913 306 : }
914 :
915 : /*
916 : * set_tablesample_rel_pathlist
917 : * Build access paths for a sampled relation
918 : */
919 : static void
920 306 : set_tablesample_rel_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
921 : {
922 : Relids required_outer;
923 : Path *path;
924 :
925 : /*
926 : * We don't support pushing join clauses into the quals of a samplescan,
927 : * but it could still have required parameterization due to LATERAL refs
928 : * in its tlist or TABLESAMPLE arguments.
929 : */
930 306 : required_outer = rel->lateral_relids;
931 :
932 : /* Consider sampled scan */
933 306 : path = create_samplescan_path(root, rel, required_outer);
934 :
935 : /*
936 : * If the sampling method does not support repeatable scans, we must avoid
937 : * plans that would scan the rel multiple times. Ideally, we'd simply
938 : * avoid putting the rel on the inside of a nestloop join; but adding such
939 : * a consideration to the planner seems like a great deal of complication
940 : * to support an uncommon usage of second-rate sampling methods. Instead,
941 : * if there is a risk that the query might perform an unsafe join, just
942 : * wrap the SampleScan in a Materialize node. We can check for joins by
943 : * counting the membership of all_query_rels (note that this correctly
944 : * counts inheritance trees as single rels). If we're inside a subquery,
945 : * we can't easily check whether a join might occur in the outer query, so
946 : * just assume one is possible.
947 : *
948 : * GetTsmRoutine is relatively expensive compared to the other tests here,
949 : * so check repeatable_across_scans last, even though that's a bit odd.
950 : */
951 586 : if ((root->query_level > 1 ||
952 280 : bms_membership(root->all_query_rels) != BMS_SINGLETON) &&
953 98 : !(GetTsmRoutine(rte->tablesample->tsmhandler)->repeatable_across_scans))
954 : {
955 8 : path = (Path *) create_material_path(rel, path);
956 : }
957 :
958 306 : add_path(rel, path);
959 :
960 : /* For the moment, at least, there are no other paths to consider */
961 306 : }
962 :
963 : /*
964 : * set_foreign_size
965 : * Set size estimates for a foreign table RTE
966 : */
967 : static void
968 2462 : set_foreign_size(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
969 : {
970 : /* Mark rel with estimated output rows, width, etc */
971 2462 : set_foreign_size_estimates(root, rel);
972 :
973 : /* Let FDW adjust the size estimates, if it can */
974 2462 : rel->fdwroutine->GetForeignRelSize(root, rel, rte->relid);
975 :
976 : /* ... but do not let it set the rows estimate to zero */
977 2458 : rel->rows = clamp_row_est(rel->rows);
978 :
979 : /*
980 : * Also, make sure rel->tuples is not insane relative to rel->rows.
981 : * Notably, this ensures sanity if pg_class.reltuples contains -1 and the
982 : * FDW doesn't do anything to replace that.
983 : */
984 2458 : rel->tuples = Max(rel->tuples, rel->rows);
985 2458 : }
986 :
987 : /*
988 : * set_foreign_pathlist
989 : * Build access paths for a foreign table RTE
990 : */
991 : static void
992 2458 : set_foreign_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
993 : {
994 : /* Call the FDW's GetForeignPaths function to generate path(s) */
995 2458 : rel->fdwroutine->GetForeignPaths(root, rel, rte->relid);
996 2458 : }
997 :
998 : /*
999 : * set_append_rel_size
1000 : * Set size estimates for a simple "append relation"
1001 : *
1002 : * The passed-in rel and RTE represent the entire append relation. The
1003 : * relation's contents are computed by appending together the output of the
1004 : * individual member relations. Note that in the non-partitioned inheritance
1005 : * case, the first member relation is actually the same table as is mentioned
1006 : * in the parent RTE ... but it has a different RTE and RelOptInfo. This is
1007 : * a good thing because their outputs are not the same size.
1008 : */
1009 : static void
1010 25692 : set_append_rel_size(PlannerInfo *root, RelOptInfo *rel,
1011 : Index rti, RangeTblEntry *rte)
1012 : {
1013 25692 : int parentRTindex = rti;
1014 : bool has_live_children;
1015 : double parent_tuples;
1016 : double parent_rows;
1017 : double parent_size;
1018 : double *parent_attrsizes;
1019 : int nattrs;
1020 : ListCell *l;
1021 :
1022 : /* Guard against stack overflow due to overly deep inheritance tree. */
1023 25692 : check_stack_depth();
1024 :
1025 : Assert(IS_SIMPLE_REL(rel));
1026 :
1027 : /*
1028 : * If this is a partitioned baserel, set the consider_partitionwise_join
1029 : * flag; currently, we only consider partitionwise joins with the baserel
1030 : * if its targetlist doesn't contain a whole-row Var.
1031 : */
1032 25692 : if (enable_partitionwise_join &&
1033 4994 : rel->reloptkind == RELOPT_BASEREL &&
1034 3974 : rte->relkind == RELKIND_PARTITIONED_TABLE &&
1035 3974 : bms_is_empty(rel->attr_needed[InvalidAttrNumber - rel->min_attr]))
1036 3898 : rel->consider_partitionwise_join = true;
1037 :
1038 : /*
1039 : * Initialize to compute size estimates for whole append relation.
1040 : *
1041 : * We handle tuples estimates by setting "tuples" to the total number of
1042 : * tuples accumulated from each live child, rather than using "rows".
1043 : * Although an appendrel itself doesn't directly enforce any quals, its
1044 : * child relations may. Therefore, setting "tuples" equal to "rows" for
1045 : * an appendrel isn't always appropriate, and can lead to inaccurate cost
1046 : * estimates. For example, when estimating the number of distinct values
1047 : * from an appendrel, we would be unable to adjust the estimate based on
1048 : * the restriction selectivity (see estimate_num_groups).
1049 : *
1050 : * We handle width estimates by weighting the widths of different child
1051 : * rels proportionally to their number of rows. This is sensible because
1052 : * the use of width estimates is mainly to compute the total relation
1053 : * "footprint" if we have to sort or hash it. To do this, we sum the
1054 : * total equivalent size (in "double" arithmetic) and then divide by the
1055 : * total rowcount estimate. This is done separately for the total rel
1056 : * width and each attribute.
1057 : *
1058 : * Note: if you consider changing this logic, beware that child rels could
1059 : * have zero rows and/or width, if they were excluded by constraints.
1060 : */
1061 25692 : has_live_children = false;
1062 25692 : parent_tuples = 0;
1063 25692 : parent_rows = 0;
1064 25692 : parent_size = 0;
1065 25692 : nattrs = rel->max_attr - rel->min_attr + 1;
1066 25692 : parent_attrsizes = (double *) palloc0(nattrs * sizeof(double));
1067 :
1068 135102 : foreach(l, root->append_rel_list)
1069 : {
1070 109412 : AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
1071 : int childRTindex;
1072 : RangeTblEntry *childRTE;
1073 : RelOptInfo *childrel;
1074 : List *childrinfos;
1075 : ListCell *parentvars;
1076 : ListCell *childvars;
1077 : ListCell *lc;
1078 :
1079 : /* append_rel_list contains all append rels; ignore others */
1080 109412 : if (appinfo->parent_relid != parentRTindex)
1081 51780 : continue;
1082 :
1083 57974 : childRTindex = appinfo->child_relid;
1084 57974 : childRTE = root->simple_rte_array[childRTindex];
1085 :
1086 : /*
1087 : * The child rel's RelOptInfo was already created during
1088 : * add_other_rels_to_query.
1089 : */
1090 57974 : childrel = find_base_rel(root, childRTindex);
1091 : Assert(childrel->reloptkind == RELOPT_OTHER_MEMBER_REL);
1092 :
1093 : /* We may have already proven the child to be dummy. */
1094 57974 : if (IS_DUMMY_REL(childrel))
1095 18 : continue;
1096 :
1097 : /*
1098 : * We have to copy the parent's targetlist and quals to the child,
1099 : * with appropriate substitution of variables. However, the
1100 : * baserestrictinfo quals were already copied/substituted when the
1101 : * child RelOptInfo was built. So we don't need any additional setup
1102 : * before applying constraint exclusion.
1103 : */
1104 57956 : if (relation_excluded_by_constraints(root, childrel, childRTE))
1105 : {
1106 : /*
1107 : * This child need not be scanned, so we can omit it from the
1108 : * appendrel.
1109 : */
1110 186 : set_dummy_rel_pathlist(childrel);
1111 186 : continue;
1112 : }
1113 :
1114 : /*
1115 : * Constraint exclusion failed, so copy the parent's join quals and
1116 : * targetlist to the child, with appropriate variable substitutions.
1117 : *
1118 : * We skip join quals that came from above outer joins that can null
1119 : * this rel, since they would be of no value while generating paths
1120 : * for the child. This saves some effort while processing the child
1121 : * rel, and it also avoids an implementation restriction in
1122 : * adjust_appendrel_attrs (it can't apply nullingrels to a non-Var).
1123 : */
1124 57770 : childrinfos = NIL;
1125 70958 : foreach(lc, rel->joininfo)
1126 : {
1127 13188 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
1128 :
1129 13188 : if (!bms_overlap(rinfo->clause_relids, rel->nulling_relids))
1130 10866 : childrinfos = lappend(childrinfos,
1131 10866 : adjust_appendrel_attrs(root,
1132 : (Node *) rinfo,
1133 : 1, &appinfo));
1134 : }
1135 57770 : childrel->joininfo = childrinfos;
1136 :
1137 : /*
1138 : * Now for the child's targetlist.
1139 : *
1140 : * NB: the resulting childrel->reltarget->exprs may contain arbitrary
1141 : * expressions, which otherwise would not occur in a rel's targetlist.
1142 : * Code that might be looking at an appendrel child must cope with
1143 : * such. (Normally, a rel's targetlist would only include Vars and
1144 : * PlaceHolderVars.) XXX we do not bother to update the cost or width
1145 : * fields of childrel->reltarget; not clear if that would be useful.
1146 : */
1147 115540 : childrel->reltarget->exprs = (List *)
1148 57770 : adjust_appendrel_attrs(root,
1149 57770 : (Node *) rel->reltarget->exprs,
1150 : 1, &appinfo);
1151 :
1152 : /*
1153 : * We have to make child entries in the EquivalenceClass data
1154 : * structures as well. This is needed either if the parent
1155 : * participates in some eclass joins (because we will want to consider
1156 : * inner-indexscan joins on the individual children) or if the parent
1157 : * has useful pathkeys (because we should try to build MergeAppend
1158 : * paths that produce those sort orderings).
1159 : */
1160 57770 : if (rel->has_eclass_joins || has_useful_pathkeys(root, rel))
1161 35370 : add_child_rel_equivalences(root, appinfo, rel, childrel);
1162 57770 : childrel->has_eclass_joins = rel->has_eclass_joins;
1163 :
1164 : /*
1165 : * Note: we could compute appropriate attr_needed data for the child's
1166 : * variables, by transforming the parent's attr_needed through the
1167 : * translated_vars mapping. However, currently there's no need
1168 : * because attr_needed is only examined for base relations not
1169 : * otherrels. So we just leave the child's attr_needed empty.
1170 : */
1171 :
1172 : /*
1173 : * If we consider partitionwise joins with the parent rel, do the same
1174 : * for partitioned child rels.
1175 : *
1176 : * Note: here we abuse the consider_partitionwise_join flag by setting
1177 : * it for child rels that are not themselves partitioned. We do so to
1178 : * tell try_partitionwise_join() that the child rel is sufficiently
1179 : * valid to be used as a per-partition input, even if it later gets
1180 : * proven to be dummy. (It's not usable until we've set up the
1181 : * reltarget and EC entries, which we just did.)
1182 : */
1183 57770 : if (rel->consider_partitionwise_join)
1184 13184 : childrel->consider_partitionwise_join = true;
1185 :
1186 : /*
1187 : * If parallelism is allowable for this query in general, see whether
1188 : * it's allowable for this childrel in particular. But if we've
1189 : * already decided the appendrel is not parallel-safe as a whole,
1190 : * there's no point in considering parallelism for this child. For
1191 : * consistency, do this before calling set_rel_size() for the child.
1192 : */
1193 57770 : if (root->glob->parallelModeOK && rel->consider_parallel)
1194 43160 : set_rel_consider_parallel(root, childrel, childRTE);
1195 :
1196 : /*
1197 : * Compute the child's size.
1198 : */
1199 57770 : set_rel_size(root, childrel, childRTindex, childRTE);
1200 :
1201 : /*
1202 : * It is possible that constraint exclusion detected a contradiction
1203 : * within a child subquery, even though we didn't prove one above. If
1204 : * so, we can skip this child.
1205 : */
1206 57768 : if (IS_DUMMY_REL(childrel))
1207 138 : continue;
1208 :
1209 : /* We have at least one live child. */
1210 57630 : has_live_children = true;
1211 :
1212 : /*
1213 : * If any live child is not parallel-safe, treat the whole appendrel
1214 : * as not parallel-safe. In future we might be able to generate plans
1215 : * in which some children are farmed out to workers while others are
1216 : * not; but we don't have that today, so it's a waste to consider
1217 : * partial paths anywhere in the appendrel unless it's all safe.
1218 : * (Child rels visited before this one will be unmarked in
1219 : * set_append_rel_pathlist().)
1220 : */
1221 57630 : if (!childrel->consider_parallel)
1222 15302 : rel->consider_parallel = false;
1223 :
1224 : /*
1225 : * Accumulate size information from each live child.
1226 : */
1227 : Assert(childrel->rows > 0);
1228 :
1229 57630 : parent_tuples += childrel->tuples;
1230 57630 : parent_rows += childrel->rows;
1231 57630 : parent_size += childrel->reltarget->width * childrel->rows;
1232 :
1233 : /*
1234 : * Accumulate per-column estimates too. We need not do anything for
1235 : * PlaceHolderVars in the parent list. If child expression isn't a
1236 : * Var, or we didn't record a width estimate for it, we have to fall
1237 : * back on a datatype-based estimate.
1238 : *
1239 : * By construction, child's targetlist is 1-to-1 with parent's.
1240 : */
1241 189472 : forboth(parentvars, rel->reltarget->exprs,
1242 : childvars, childrel->reltarget->exprs)
1243 : {
1244 131842 : Var *parentvar = (Var *) lfirst(parentvars);
1245 131842 : Node *childvar = (Node *) lfirst(childvars);
1246 :
1247 131842 : if (IsA(parentvar, Var) && parentvar->varno == parentRTindex)
1248 : {
1249 118914 : int pndx = parentvar->varattno - rel->min_attr;
1250 118914 : int32 child_width = 0;
1251 :
1252 118914 : if (IsA(childvar, Var) &&
1253 114134 : ((Var *) childvar)->varno == childrel->relid)
1254 : {
1255 114068 : int cndx = ((Var *) childvar)->varattno - childrel->min_attr;
1256 :
1257 114068 : child_width = childrel->attr_widths[cndx];
1258 : }
1259 118914 : if (child_width <= 0)
1260 4846 : child_width = get_typavgwidth(exprType(childvar),
1261 : exprTypmod(childvar));
1262 : Assert(child_width > 0);
1263 118914 : parent_attrsizes[pndx] += child_width * childrel->rows;
1264 : }
1265 : }
1266 : }
1267 :
1268 25690 : if (has_live_children)
1269 : {
1270 : /*
1271 : * Save the finished size estimates.
1272 : */
1273 : int i;
1274 :
1275 : Assert(parent_rows > 0);
1276 25396 : rel->tuples = parent_tuples;
1277 25396 : rel->rows = parent_rows;
1278 25396 : rel->reltarget->width = rint(parent_size / parent_rows);
1279 236436 : for (i = 0; i < nattrs; i++)
1280 211040 : rel->attr_widths[i] = rint(parent_attrsizes[i] / parent_rows);
1281 :
1282 : /*
1283 : * Note that we leave rel->pages as zero; this is important to avoid
1284 : * double-counting the appendrel tree in total_table_pages.
1285 : */
1286 : }
1287 : else
1288 : {
1289 : /*
1290 : * All children were excluded by constraints, so mark the whole
1291 : * appendrel dummy. We must do this in this phase so that the rel's
1292 : * dummy-ness is visible when we generate paths for other rels.
1293 : */
1294 294 : set_dummy_rel_pathlist(rel);
1295 : }
1296 :
1297 25690 : pfree(parent_attrsizes);
1298 25690 : }
1299 :
1300 : /*
1301 : * set_append_rel_pathlist
1302 : * Build access paths for an "append relation"
1303 : */
1304 : static void
1305 25396 : set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
1306 : Index rti, RangeTblEntry *rte)
1307 : {
1308 25396 : int parentRTindex = rti;
1309 25396 : List *live_childrels = NIL;
1310 : ListCell *l;
1311 :
1312 : /*
1313 : * Generate access paths for each member relation, and remember the
1314 : * non-dummy children.
1315 : */
1316 134392 : foreach(l, root->append_rel_list)
1317 : {
1318 108996 : AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
1319 : int childRTindex;
1320 : RangeTblEntry *childRTE;
1321 : RelOptInfo *childrel;
1322 :
1323 : /* append_rel_list contains all append rels; ignore others */
1324 108996 : if (appinfo->parent_relid != parentRTindex)
1325 51090 : continue;
1326 :
1327 : /* Re-locate the child RTE and RelOptInfo */
1328 57906 : childRTindex = appinfo->child_relid;
1329 57906 : childRTE = root->simple_rte_array[childRTindex];
1330 57906 : childrel = root->simple_rel_array[childRTindex];
1331 :
1332 : /*
1333 : * If set_append_rel_size() decided the parent appendrel was
1334 : * parallel-unsafe at some point after visiting this child rel, we
1335 : * need to propagate the unsafety marking down to the child, so that
1336 : * we don't generate useless partial paths for it.
1337 : */
1338 57906 : if (!rel->consider_parallel)
1339 15498 : childrel->consider_parallel = false;
1340 :
1341 : /*
1342 : * Compute the child's access paths.
1343 : */
1344 57906 : set_rel_pathlist(root, childrel, childRTindex, childRTE);
1345 :
1346 : /*
1347 : * If child is dummy, ignore it.
1348 : */
1349 57906 : if (IS_DUMMY_REL(childrel))
1350 276 : continue;
1351 :
1352 : /*
1353 : * Child is live, so add it to the live_childrels list for use below.
1354 : */
1355 57630 : live_childrels = lappend(live_childrels, childrel);
1356 : }
1357 :
1358 : /* Add paths to the append relation. */
1359 25396 : add_paths_to_append_rel(root, rel, live_childrels);
1360 25396 : }
1361 :
1362 : /*
1363 : * set_grouped_rel_pathlist
1364 : * If a grouped relation for the given 'rel' exists, build partial
1365 : * aggregation paths for it.
1366 : */
1367 : static void
1368 523086 : set_grouped_rel_pathlist(PlannerInfo *root, RelOptInfo *rel)
1369 : {
1370 : RelOptInfo *grouped_rel;
1371 :
1372 : /*
1373 : * If there are no aggregate expressions or grouping expressions, eager
1374 : * aggregation is not possible.
1375 : */
1376 523086 : if (root->agg_clause_list == NIL ||
1377 3332 : root->group_expr_list == NIL)
1378 520018 : return;
1379 :
1380 : /* Add paths to the grouped base relation if one exists. */
1381 3068 : grouped_rel = rel->grouped_rel;
1382 3068 : if (grouped_rel)
1383 : {
1384 : Assert(IS_GROUPED_REL(grouped_rel));
1385 :
1386 586 : generate_grouped_paths(root, grouped_rel, rel);
1387 586 : set_cheapest(grouped_rel);
1388 : }
1389 : }
1390 :
1391 :
1392 : /*
1393 : * add_paths_to_append_rel
1394 : * Generate paths for the given append relation given the set of non-dummy
1395 : * child rels.
1396 : *
1397 : * The function collects all parameterizations and orderings supported by the
1398 : * non-dummy children. For every such parameterization or ordering, it creates
1399 : * an append path collecting one path from each non-dummy child with given
1400 : * parameterization or ordering. Similarly it collects partial paths from
1401 : * non-dummy children to create partial append paths.
1402 : */
1403 : void
1404 46520 : add_paths_to_append_rel(PlannerInfo *root, RelOptInfo *rel,
1405 : List *live_childrels)
1406 : {
1407 46520 : List *subpaths = NIL;
1408 46520 : bool subpaths_valid = true;
1409 46520 : List *startup_subpaths = NIL;
1410 46520 : bool startup_subpaths_valid = true;
1411 46520 : List *partial_subpaths = NIL;
1412 46520 : List *pa_partial_subpaths = NIL;
1413 46520 : List *pa_nonpartial_subpaths = NIL;
1414 46520 : bool partial_subpaths_valid = true;
1415 : bool pa_subpaths_valid;
1416 46520 : List *all_child_pathkeys = NIL;
1417 46520 : List *all_child_outers = NIL;
1418 : ListCell *l;
1419 46520 : double partial_rows = -1;
1420 :
1421 : /* If appropriate, consider parallel append */
1422 46520 : pa_subpaths_valid = enable_parallel_append && rel->consider_parallel;
1423 :
1424 : /*
1425 : * For every non-dummy child, remember the cheapest path. Also, identify
1426 : * all pathkeys (orderings) and parameterizations (required_outer sets)
1427 : * available for the non-dummy member relations.
1428 : */
1429 148878 : foreach(l, live_childrels)
1430 : {
1431 102358 : RelOptInfo *childrel = lfirst(l);
1432 : ListCell *lcp;
1433 102358 : Path *cheapest_partial_path = NULL;
1434 :
1435 : /*
1436 : * If child has an unparameterized cheapest-total path, add that to
1437 : * the unparameterized Append path we are constructing for the parent.
1438 : * If not, there's no workable unparameterized path.
1439 : *
1440 : * With partitionwise aggregates, the child rel's pathlist may be
1441 : * empty, so don't assume that a path exists here.
1442 : */
1443 102358 : if (childrel->pathlist != NIL &&
1444 102358 : childrel->cheapest_total_path->param_info == NULL)
1445 101626 : accumulate_append_subpath(childrel->cheapest_total_path,
1446 : &subpaths, NULL);
1447 : else
1448 732 : subpaths_valid = false;
1449 :
1450 : /*
1451 : * When the planner is considering cheap startup plans, we'll also
1452 : * collect all the cheapest_startup_paths (if set) and build an
1453 : * AppendPath containing those as subpaths.
1454 : */
1455 102358 : if (rel->consider_startup && childrel->cheapest_startup_path != NULL)
1456 1730 : {
1457 : Path *cheapest_path;
1458 :
1459 : /*
1460 : * With an indication of how many tuples the query should provide,
1461 : * the optimizer tries to choose the path optimal for that
1462 : * specific number of tuples.
1463 : */
1464 1730 : if (root->tuple_fraction > 0.0)
1465 : cheapest_path =
1466 1730 : get_cheapest_fractional_path(childrel,
1467 : root->tuple_fraction);
1468 : else
1469 0 : cheapest_path = childrel->cheapest_startup_path;
1470 :
1471 : /* cheapest_startup_path must not be a parameterized path. */
1472 : Assert(cheapest_path->param_info == NULL);
1473 1730 : accumulate_append_subpath(cheapest_path,
1474 : &startup_subpaths,
1475 : NULL);
1476 : }
1477 : else
1478 100628 : startup_subpaths_valid = false;
1479 :
1480 :
1481 : /* Same idea, but for a partial plan. */
1482 102358 : if (childrel->partial_pathlist != NIL)
1483 : {
1484 63282 : cheapest_partial_path = linitial(childrel->partial_pathlist);
1485 63282 : accumulate_append_subpath(cheapest_partial_path,
1486 : &partial_subpaths, NULL);
1487 : }
1488 : else
1489 39076 : partial_subpaths_valid = false;
1490 :
1491 : /*
1492 : * Same idea, but for a parallel append mixing partial and non-partial
1493 : * paths.
1494 : */
1495 102358 : if (pa_subpaths_valid)
1496 : {
1497 77110 : Path *nppath = NULL;
1498 :
1499 : nppath =
1500 77110 : get_cheapest_parallel_safe_total_inner(childrel->pathlist);
1501 :
1502 77110 : if (cheapest_partial_path == NULL && nppath == NULL)
1503 : {
1504 : /* Neither a partial nor a parallel-safe path? Forget it. */
1505 546 : pa_subpaths_valid = false;
1506 : }
1507 76564 : else if (nppath == NULL ||
1508 62832 : (cheapest_partial_path != NULL &&
1509 62832 : cheapest_partial_path->total_cost < nppath->total_cost))
1510 : {
1511 : /* Partial path is cheaper or the only option. */
1512 : Assert(cheapest_partial_path != NULL);
1513 62692 : accumulate_append_subpath(cheapest_partial_path,
1514 : &pa_partial_subpaths,
1515 : &pa_nonpartial_subpaths);
1516 : }
1517 : else
1518 : {
1519 : /*
1520 : * Either we've got only a non-partial path, or we think that
1521 : * a single backend can execute the best non-partial path
1522 : * faster than all the parallel backends working together can
1523 : * execute the best partial path.
1524 : *
1525 : * It might make sense to be more aggressive here. Even if
1526 : * the best non-partial path is more expensive than the best
1527 : * partial path, it could still be better to choose the
1528 : * non-partial path if there are several such paths that can
1529 : * be given to different workers. For now, we don't try to
1530 : * figure that out.
1531 : */
1532 13872 : accumulate_append_subpath(nppath,
1533 : &pa_nonpartial_subpaths,
1534 : NULL);
1535 : }
1536 : }
1537 :
1538 : /*
1539 : * Collect lists of all the available path orderings and
1540 : * parameterizations for all the children. We use these as a
1541 : * heuristic to indicate which sort orderings and parameterizations we
1542 : * should build Append and MergeAppend paths for.
1543 : */
1544 241916 : foreach(lcp, childrel->pathlist)
1545 : {
1546 139558 : Path *childpath = (Path *) lfirst(lcp);
1547 139558 : List *childkeys = childpath->pathkeys;
1548 139558 : Relids childouter = PATH_REQ_OUTER(childpath);
1549 :
1550 : /* Unsorted paths don't contribute to pathkey list */
1551 139558 : if (childkeys != NIL)
1552 : {
1553 : ListCell *lpk;
1554 36854 : bool found = false;
1555 :
1556 : /* Have we already seen this ordering? */
1557 37084 : foreach(lpk, all_child_pathkeys)
1558 : {
1559 24916 : List *existing_pathkeys = (List *) lfirst(lpk);
1560 :
1561 24916 : if (compare_pathkeys(existing_pathkeys,
1562 : childkeys) == PATHKEYS_EQUAL)
1563 : {
1564 24686 : found = true;
1565 24686 : break;
1566 : }
1567 : }
1568 36854 : if (!found)
1569 : {
1570 : /* No, so add it to all_child_pathkeys */
1571 12168 : all_child_pathkeys = lappend(all_child_pathkeys,
1572 : childkeys);
1573 : }
1574 : }
1575 :
1576 : /* Unparameterized paths don't contribute to param-set list */
1577 139558 : if (childouter)
1578 : {
1579 : ListCell *lco;
1580 6596 : bool found = false;
1581 :
1582 : /* Have we already seen this param set? */
1583 7316 : foreach(lco, all_child_outers)
1584 : {
1585 4810 : Relids existing_outers = (Relids) lfirst(lco);
1586 :
1587 4810 : if (bms_equal(existing_outers, childouter))
1588 : {
1589 4090 : found = true;
1590 4090 : break;
1591 : }
1592 : }
1593 6596 : if (!found)
1594 : {
1595 : /* No, so add it to all_child_outers */
1596 2506 : all_child_outers = lappend(all_child_outers,
1597 : childouter);
1598 : }
1599 : }
1600 : }
1601 : }
1602 :
1603 : /*
1604 : * If we found unparameterized paths for all children, build an unordered,
1605 : * unparameterized Append path for the rel. (Note: this is correct even
1606 : * if we have zero or one live subpath due to constraint exclusion.)
1607 : */
1608 46520 : if (subpaths_valid)
1609 46208 : add_path(rel, (Path *) create_append_path(root, rel, subpaths, NIL,
1610 : NIL, NULL, 0, false,
1611 : -1));
1612 :
1613 : /* build an AppendPath for the cheap startup paths, if valid */
1614 46520 : if (startup_subpaths_valid)
1615 700 : add_path(rel, (Path *) create_append_path(root, rel, startup_subpaths,
1616 : NIL, NIL, NULL, 0, false, -1));
1617 :
1618 : /*
1619 : * Consider an append of unordered, unparameterized partial paths. Make
1620 : * it parallel-aware if possible.
1621 : */
1622 46520 : if (partial_subpaths_valid && partial_subpaths != NIL)
1623 : {
1624 : AppendPath *appendpath;
1625 : ListCell *lc;
1626 27738 : int parallel_workers = 0;
1627 :
1628 : /* Find the highest number of workers requested for any subpath. */
1629 95326 : foreach(lc, partial_subpaths)
1630 : {
1631 67588 : Path *path = lfirst(lc);
1632 :
1633 67588 : parallel_workers = Max(parallel_workers, path->parallel_workers);
1634 : }
1635 : Assert(parallel_workers > 0);
1636 :
1637 : /*
1638 : * If the use of parallel append is permitted, always request at least
1639 : * log2(# of children) workers. We assume it can be useful to have
1640 : * extra workers in this case because they will be spread out across
1641 : * the children. The precise formula is just a guess, but we don't
1642 : * want to end up with a radically different answer for a table with N
1643 : * partitions vs. an unpartitioned table with the same data, so the
1644 : * use of some kind of log-scaling here seems to make some sense.
1645 : */
1646 27738 : if (enable_parallel_append)
1647 : {
1648 27690 : parallel_workers = Max(parallel_workers,
1649 : pg_leftmost_one_pos32(list_length(live_childrels)) + 1);
1650 27690 : parallel_workers = Min(parallel_workers,
1651 : max_parallel_workers_per_gather);
1652 : }
1653 : Assert(parallel_workers > 0);
1654 :
1655 : /* Generate a partial append path. */
1656 27738 : appendpath = create_append_path(root, rel, NIL, partial_subpaths,
1657 : NIL, NULL, parallel_workers,
1658 : enable_parallel_append,
1659 : -1);
1660 :
1661 : /*
1662 : * Make sure any subsequent partial paths use the same row count
1663 : * estimate.
1664 : */
1665 27738 : partial_rows = appendpath->path.rows;
1666 :
1667 : /* Add the path. */
1668 27738 : add_partial_path(rel, (Path *) appendpath);
1669 : }
1670 :
1671 : /*
1672 : * Consider a parallel-aware append using a mix of partial and non-partial
1673 : * paths. (This only makes sense if there's at least one child which has
1674 : * a non-partial path that is substantially cheaper than any partial path;
1675 : * otherwise, we should use the append path added in the previous step.)
1676 : */
1677 46520 : if (pa_subpaths_valid && pa_nonpartial_subpaths != NIL)
1678 : {
1679 : AppendPath *appendpath;
1680 : ListCell *lc;
1681 4966 : int parallel_workers = 0;
1682 :
1683 : /*
1684 : * Find the highest number of workers requested for any partial
1685 : * subpath.
1686 : */
1687 5868 : foreach(lc, pa_partial_subpaths)
1688 : {
1689 902 : Path *path = lfirst(lc);
1690 :
1691 902 : parallel_workers = Max(parallel_workers, path->parallel_workers);
1692 : }
1693 :
1694 : /*
1695 : * Same formula here as above. It's even more important in this
1696 : * instance because the non-partial paths won't contribute anything to
1697 : * the planned number of parallel workers.
1698 : */
1699 4966 : parallel_workers = Max(parallel_workers,
1700 : pg_leftmost_one_pos32(list_length(live_childrels)) + 1);
1701 4966 : parallel_workers = Min(parallel_workers,
1702 : max_parallel_workers_per_gather);
1703 : Assert(parallel_workers > 0);
1704 :
1705 4966 : appendpath = create_append_path(root, rel, pa_nonpartial_subpaths,
1706 : pa_partial_subpaths,
1707 : NIL, NULL, parallel_workers, true,
1708 : partial_rows);
1709 4966 : add_partial_path(rel, (Path *) appendpath);
1710 : }
1711 :
1712 : /*
1713 : * Also build unparameterized ordered append paths based on the collected
1714 : * list of child pathkeys.
1715 : */
1716 46520 : if (subpaths_valid)
1717 46208 : generate_orderedappend_paths(root, rel, live_childrels,
1718 : all_child_pathkeys);
1719 :
1720 : /*
1721 : * Build Append paths for each parameterization seen among the child rels.
1722 : * (This may look pretty expensive, but in most cases of practical
1723 : * interest, the child rels will expose mostly the same parameterizations,
1724 : * so that not that many cases actually get considered here.)
1725 : *
1726 : * The Append node itself cannot enforce quals, so all qual checking must
1727 : * be done in the child paths. This means that to have a parameterized
1728 : * Append path, we must have the exact same parameterization for each
1729 : * child path; otherwise some children might be failing to check the
1730 : * moved-down quals. To make them match up, we can try to increase the
1731 : * parameterization of lesser-parameterized paths.
1732 : */
1733 49026 : foreach(l, all_child_outers)
1734 : {
1735 2506 : Relids required_outer = (Relids) lfirst(l);
1736 : ListCell *lcr;
1737 :
1738 : /* Select the child paths for an Append with this parameterization */
1739 2506 : subpaths = NIL;
1740 2506 : subpaths_valid = true;
1741 9198 : foreach(lcr, live_childrels)
1742 : {
1743 6704 : RelOptInfo *childrel = (RelOptInfo *) lfirst(lcr);
1744 : Path *subpath;
1745 :
1746 6704 : if (childrel->pathlist == NIL)
1747 : {
1748 : /* failed to make a suitable path for this child */
1749 0 : subpaths_valid = false;
1750 0 : break;
1751 : }
1752 :
1753 6704 : subpath = get_cheapest_parameterized_child_path(root,
1754 : childrel,
1755 : required_outer);
1756 6704 : if (subpath == NULL)
1757 : {
1758 : /* failed to make a suitable path for this child */
1759 12 : subpaths_valid = false;
1760 12 : break;
1761 : }
1762 6692 : accumulate_append_subpath(subpath, &subpaths, NULL);
1763 : }
1764 :
1765 2506 : if (subpaths_valid)
1766 2494 : add_path(rel, (Path *)
1767 2494 : create_append_path(root, rel, subpaths, NIL,
1768 : NIL, required_outer, 0, false,
1769 : -1));
1770 : }
1771 :
1772 : /*
1773 : * When there is only a single child relation, the Append path can inherit
1774 : * any ordering available for the child rel's path, so that it's useful to
1775 : * consider ordered partial paths. Above we only considered the cheapest
1776 : * partial path for each child, but let's also make paths using any
1777 : * partial paths that have pathkeys.
1778 : */
1779 46520 : if (list_length(live_childrels) == 1)
1780 : {
1781 14380 : RelOptInfo *childrel = (RelOptInfo *) linitial(live_childrels);
1782 :
1783 : /* skip the cheapest partial path, since we already used that above */
1784 14584 : for_each_from(l, childrel->partial_pathlist, 1)
1785 : {
1786 204 : Path *path = (Path *) lfirst(l);
1787 : AppendPath *appendpath;
1788 :
1789 : /* skip paths with no pathkeys. */
1790 204 : if (path->pathkeys == NIL)
1791 0 : continue;
1792 :
1793 204 : appendpath = create_append_path(root, rel, NIL, list_make1(path),
1794 : NIL, NULL,
1795 : path->parallel_workers, true,
1796 : partial_rows);
1797 204 : add_partial_path(rel, (Path *) appendpath);
1798 : }
1799 : }
1800 46520 : }
1801 :
1802 : /*
1803 : * generate_orderedappend_paths
1804 : * Generate ordered append paths for an append relation
1805 : *
1806 : * Usually we generate MergeAppend paths here, but there are some special
1807 : * cases where we can generate simple Append paths, because the subpaths
1808 : * can provide tuples in the required order already.
1809 : *
1810 : * We generate a path for each ordering (pathkey list) appearing in
1811 : * all_child_pathkeys.
1812 : *
1813 : * We consider the cheapest-startup and cheapest-total cases, and also the
1814 : * cheapest-fractional case when not all tuples need to be retrieved. For each
1815 : * interesting ordering, we collect all the cheapest startup subpaths, all the
1816 : * cheapest total paths, and, if applicable, all the cheapest fractional paths,
1817 : * and build a suitable path for each case.
1818 : *
1819 : * We don't currently generate any parameterized ordered paths here. While
1820 : * it would not take much more code here to do so, it's very unclear that it
1821 : * is worth the planning cycles to investigate such paths: there's little
1822 : * use for an ordered path on the inside of a nestloop. In fact, it's likely
1823 : * that the current coding of add_path would reject such paths out of hand,
1824 : * because add_path gives no credit for sort ordering of parameterized paths,
1825 : * and a parameterized MergeAppend is going to be more expensive than the
1826 : * corresponding parameterized Append path. If we ever try harder to support
1827 : * parameterized mergejoin plans, it might be worth adding support for
1828 : * parameterized paths here to feed such joins. (See notes in
1829 : * optimizer/README for why that might not ever happen, though.)
1830 : */
1831 : static void
1832 46208 : generate_orderedappend_paths(PlannerInfo *root, RelOptInfo *rel,
1833 : List *live_childrels,
1834 : List *all_child_pathkeys)
1835 : {
1836 : ListCell *lcp;
1837 46208 : List *partition_pathkeys = NIL;
1838 46208 : List *partition_pathkeys_desc = NIL;
1839 46208 : bool partition_pathkeys_partial = true;
1840 46208 : bool partition_pathkeys_desc_partial = true;
1841 :
1842 : /*
1843 : * Some partitioned table setups may allow us to use an Append node
1844 : * instead of a MergeAppend. This is possible in cases such as RANGE
1845 : * partitioned tables where it's guaranteed that an earlier partition must
1846 : * contain rows which come earlier in the sort order. To detect whether
1847 : * this is relevant, build pathkey descriptions of the partition ordering,
1848 : * for both forward and reverse scans.
1849 : */
1850 74594 : if (rel->part_scheme != NULL && IS_SIMPLE_REL(rel) &&
1851 28386 : partitions_are_ordered(rel->boundinfo, rel->live_parts))
1852 : {
1853 23814 : partition_pathkeys = build_partition_pathkeys(root, rel,
1854 : ForwardScanDirection,
1855 : &partition_pathkeys_partial);
1856 :
1857 23814 : partition_pathkeys_desc = build_partition_pathkeys(root, rel,
1858 : BackwardScanDirection,
1859 : &partition_pathkeys_desc_partial);
1860 :
1861 : /*
1862 : * You might think we should truncate_useless_pathkeys here, but
1863 : * allowing partition keys which are a subset of the query's pathkeys
1864 : * can often be useful. For example, consider a table partitioned by
1865 : * RANGE (a, b), and a query with ORDER BY a, b, c. If we have child
1866 : * paths that can produce the a, b, c ordering (perhaps via indexes on
1867 : * (a, b, c)) then it works to consider the appendrel output as
1868 : * ordered by a, b, c.
1869 : */
1870 : }
1871 :
1872 : /* Now consider each interesting sort ordering */
1873 58316 : foreach(lcp, all_child_pathkeys)
1874 : {
1875 12108 : List *pathkeys = (List *) lfirst(lcp);
1876 12108 : List *startup_subpaths = NIL;
1877 12108 : List *total_subpaths = NIL;
1878 12108 : List *fractional_subpaths = NIL;
1879 12108 : bool startup_neq_total = false;
1880 12108 : bool fraction_neq_total = false;
1881 : bool match_partition_order;
1882 : bool match_partition_order_desc;
1883 : int end_index;
1884 : int first_index;
1885 : int direction;
1886 :
1887 : /*
1888 : * Determine if this sort ordering matches any partition pathkeys we
1889 : * have, for both ascending and descending partition order. If the
1890 : * partition pathkeys happen to be contained in pathkeys then it still
1891 : * works, as described above, providing that the partition pathkeys
1892 : * are complete and not just a prefix of the partition keys. (In such
1893 : * cases we'll be relying on the child paths to have sorted the
1894 : * lower-order columns of the required pathkeys.)
1895 : */
1896 12108 : match_partition_order =
1897 21948 : pathkeys_contained_in(pathkeys, partition_pathkeys) ||
1898 10048 : (!partition_pathkeys_partial &&
1899 208 : pathkeys_contained_in(partition_pathkeys, pathkeys));
1900 :
1901 31536 : match_partition_order_desc = !match_partition_order &&
1902 9732 : (pathkeys_contained_in(pathkeys, partition_pathkeys_desc) ||
1903 9760 : (!partition_pathkeys_desc_partial &&
1904 64 : pathkeys_contained_in(partition_pathkeys_desc, pathkeys)));
1905 :
1906 : /*
1907 : * When the required pathkeys match the reverse of the partition
1908 : * order, we must build the list of paths in reverse starting with the
1909 : * last matching partition first. We can get away without making any
1910 : * special cases for this in the loop below by just looping backward
1911 : * over the child relations in this case.
1912 : */
1913 12108 : if (match_partition_order_desc)
1914 : {
1915 : /* loop backward */
1916 48 : first_index = list_length(live_childrels) - 1;
1917 48 : end_index = -1;
1918 48 : direction = -1;
1919 :
1920 : /*
1921 : * Set this to true to save us having to check for
1922 : * match_partition_order_desc in the loop below.
1923 : */
1924 48 : match_partition_order = true;
1925 : }
1926 : else
1927 : {
1928 : /* for all other case, loop forward */
1929 12060 : first_index = 0;
1930 12060 : end_index = list_length(live_childrels);
1931 12060 : direction = 1;
1932 : }
1933 :
1934 : /* Select the child paths for this ordering... */
1935 43482 : for (int i = first_index; i != end_index; i += direction)
1936 : {
1937 31374 : RelOptInfo *childrel = list_nth_node(RelOptInfo, live_childrels, i);
1938 : Path *cheapest_startup,
1939 : *cheapest_total,
1940 31374 : *cheapest_fractional = NULL;
1941 :
1942 : /* Locate the right paths, if they are available. */
1943 : cheapest_startup =
1944 31374 : get_cheapest_path_for_pathkeys(childrel->pathlist,
1945 : pathkeys,
1946 : NULL,
1947 : STARTUP_COST,
1948 : false);
1949 : cheapest_total =
1950 31374 : get_cheapest_path_for_pathkeys(childrel->pathlist,
1951 : pathkeys,
1952 : NULL,
1953 : TOTAL_COST,
1954 : false);
1955 :
1956 : /*
1957 : * If we can't find any paths with the right order just use the
1958 : * cheapest-total path; we'll have to sort it later.
1959 : */
1960 31374 : if (cheapest_startup == NULL || cheapest_total == NULL)
1961 : {
1962 340 : cheapest_startup = cheapest_total =
1963 : childrel->cheapest_total_path;
1964 : /* Assert we do have an unparameterized path for this child */
1965 : Assert(cheapest_total->param_info == NULL);
1966 : }
1967 :
1968 : /*
1969 : * When building a fractional path, determine a cheapest
1970 : * fractional path for each child relation too. Looking at startup
1971 : * and total costs is not enough, because the cheapest fractional
1972 : * path may be dominated by two separate paths (one for startup,
1973 : * one for total).
1974 : *
1975 : * When needed (building fractional path), determine the cheapest
1976 : * fractional path too.
1977 : */
1978 31374 : if (root->tuple_fraction > 0)
1979 : {
1980 896 : double path_fraction = root->tuple_fraction;
1981 :
1982 : /*
1983 : * We should not have a dummy child relation here. However,
1984 : * we cannot use childrel->rows to compute the tuple fraction,
1985 : * as childrel can be an upper relation with an unset row
1986 : * estimate. Instead, we use the row estimate from the
1987 : * cheapest_total path, which should already have been forced
1988 : * to a sane value.
1989 : */
1990 : Assert(cheapest_total->rows > 0);
1991 :
1992 : /* Convert absolute limit to a path fraction */
1993 896 : if (path_fraction >= 1.0)
1994 896 : path_fraction /= cheapest_total->rows;
1995 :
1996 : cheapest_fractional =
1997 896 : get_cheapest_fractional_path_for_pathkeys(childrel->pathlist,
1998 : pathkeys,
1999 : NULL,
2000 : path_fraction);
2001 :
2002 : /*
2003 : * If we found no path with matching pathkeys, use the
2004 : * cheapest total path instead.
2005 : *
2006 : * XXX We might consider partially sorted paths too (with an
2007 : * incremental sort on top). But we'd have to build all the
2008 : * incremental paths, do the costing etc.
2009 : *
2010 : * Also, notice whether we actually have different paths for
2011 : * the "fractional" and "total" cases. This helps avoid
2012 : * generating two identical ordered append paths.
2013 : */
2014 896 : if (cheapest_fractional == NULL)
2015 44 : cheapest_fractional = cheapest_total;
2016 852 : else if (cheapest_fractional != cheapest_total)
2017 0 : fraction_neq_total = true;
2018 : }
2019 :
2020 : /*
2021 : * Notice whether we actually have different paths for the
2022 : * "cheapest" and "total" cases. This helps avoid generating two
2023 : * identical ordered append paths.
2024 : */
2025 31374 : if (cheapest_startup != cheapest_total)
2026 96 : startup_neq_total = true;
2027 :
2028 : /*
2029 : * Collect the appropriate child paths. The required logic varies
2030 : * for the Append and MergeAppend cases.
2031 : */
2032 31374 : if (match_partition_order)
2033 : {
2034 : /*
2035 : * We're going to make a plain Append path. We don't need
2036 : * most of what accumulate_append_subpath would do, but we do
2037 : * want to cut out child Appends or MergeAppends if they have
2038 : * just a single subpath (and hence aren't doing anything
2039 : * useful).
2040 : */
2041 6476 : cheapest_startup = get_singleton_append_subpath(cheapest_startup);
2042 6476 : cheapest_total = get_singleton_append_subpath(cheapest_total);
2043 :
2044 6476 : startup_subpaths = lappend(startup_subpaths, cheapest_startup);
2045 6476 : total_subpaths = lappend(total_subpaths, cheapest_total);
2046 :
2047 6476 : if (cheapest_fractional)
2048 : {
2049 144 : cheapest_fractional = get_singleton_append_subpath(cheapest_fractional);
2050 144 : fractional_subpaths = lappend(fractional_subpaths, cheapest_fractional);
2051 : }
2052 : }
2053 : else
2054 : {
2055 : /*
2056 : * Otherwise, rely on accumulate_append_subpath to collect the
2057 : * child paths for the MergeAppend.
2058 : */
2059 24898 : accumulate_append_subpath(cheapest_startup,
2060 : &startup_subpaths, NULL);
2061 24898 : accumulate_append_subpath(cheapest_total,
2062 : &total_subpaths, NULL);
2063 :
2064 24898 : if (cheapest_fractional)
2065 752 : accumulate_append_subpath(cheapest_fractional,
2066 : &fractional_subpaths, NULL);
2067 : }
2068 : }
2069 :
2070 : /* ... and build the Append or MergeAppend paths */
2071 12108 : if (match_partition_order)
2072 : {
2073 : /* We only need Append */
2074 2424 : add_path(rel, (Path *) create_append_path(root,
2075 : rel,
2076 : startup_subpaths,
2077 : NIL,
2078 : pathkeys,
2079 : NULL,
2080 : 0,
2081 : false,
2082 : -1));
2083 2424 : if (startup_neq_total)
2084 0 : add_path(rel, (Path *) create_append_path(root,
2085 : rel,
2086 : total_subpaths,
2087 : NIL,
2088 : pathkeys,
2089 : NULL,
2090 : 0,
2091 : false,
2092 : -1));
2093 :
2094 2424 : if (fractional_subpaths && fraction_neq_total)
2095 0 : add_path(rel, (Path *) create_append_path(root,
2096 : rel,
2097 : fractional_subpaths,
2098 : NIL,
2099 : pathkeys,
2100 : NULL,
2101 : 0,
2102 : false,
2103 : -1));
2104 : }
2105 : else
2106 : {
2107 : /* We need MergeAppend */
2108 9684 : add_path(rel, (Path *) create_merge_append_path(root,
2109 : rel,
2110 : startup_subpaths,
2111 : pathkeys,
2112 : NULL));
2113 9684 : if (startup_neq_total)
2114 60 : add_path(rel, (Path *) create_merge_append_path(root,
2115 : rel,
2116 : total_subpaths,
2117 : pathkeys,
2118 : NULL));
2119 :
2120 9684 : if (fractional_subpaths && fraction_neq_total)
2121 0 : add_path(rel, (Path *) create_merge_append_path(root,
2122 : rel,
2123 : fractional_subpaths,
2124 : pathkeys,
2125 : NULL));
2126 : }
2127 : }
2128 46208 : }
2129 :
2130 : /*
2131 : * get_cheapest_parameterized_child_path
2132 : * Get cheapest path for this relation that has exactly the requested
2133 : * parameterization.
2134 : *
2135 : * Returns NULL if unable to create such a path.
2136 : */
2137 : static Path *
2138 6704 : get_cheapest_parameterized_child_path(PlannerInfo *root, RelOptInfo *rel,
2139 : Relids required_outer)
2140 : {
2141 : Path *cheapest;
2142 : ListCell *lc;
2143 :
2144 : /*
2145 : * Look up the cheapest existing path with no more than the needed
2146 : * parameterization. If it has exactly the needed parameterization, we're
2147 : * done.
2148 : */
2149 6704 : cheapest = get_cheapest_path_for_pathkeys(rel->pathlist,
2150 : NIL,
2151 : required_outer,
2152 : TOTAL_COST,
2153 : false);
2154 : Assert(cheapest != NULL);
2155 6704 : if (bms_equal(PATH_REQ_OUTER(cheapest), required_outer))
2156 6364 : return cheapest;
2157 :
2158 : /*
2159 : * Otherwise, we can "reparameterize" an existing path to match the given
2160 : * parameterization, which effectively means pushing down additional
2161 : * joinquals to be checked within the path's scan. However, some existing
2162 : * paths might check the available joinquals already while others don't;
2163 : * therefore, it's not clear which existing path will be cheapest after
2164 : * reparameterization. We have to go through them all and find out.
2165 : */
2166 340 : cheapest = NULL;
2167 1180 : foreach(lc, rel->pathlist)
2168 : {
2169 840 : Path *path = (Path *) lfirst(lc);
2170 :
2171 : /* Can't use it if it needs more than requested parameterization */
2172 840 : if (!bms_is_subset(PATH_REQ_OUTER(path), required_outer))
2173 24 : continue;
2174 :
2175 : /*
2176 : * Reparameterization can only increase the path's cost, so if it's
2177 : * already more expensive than the current cheapest, forget it.
2178 : */
2179 1272 : if (cheapest != NULL &&
2180 456 : compare_path_costs(cheapest, path, TOTAL_COST) <= 0)
2181 384 : continue;
2182 :
2183 : /* Reparameterize if needed, then recheck cost */
2184 432 : if (!bms_equal(PATH_REQ_OUTER(path), required_outer))
2185 : {
2186 356 : path = reparameterize_path(root, path, required_outer, 1.0);
2187 356 : if (path == NULL)
2188 32 : continue; /* failed to reparameterize this one */
2189 : Assert(bms_equal(PATH_REQ_OUTER(path), required_outer));
2190 :
2191 324 : if (cheapest != NULL &&
2192 0 : compare_path_costs(cheapest, path, TOTAL_COST) <= 0)
2193 0 : continue;
2194 : }
2195 :
2196 : /* We have a new best path */
2197 400 : cheapest = path;
2198 : }
2199 :
2200 : /* Return the best path, or NULL if we found no suitable candidate */
2201 340 : return cheapest;
2202 : }
2203 :
2204 : /*
2205 : * accumulate_append_subpath
2206 : * Add a subpath to the list being built for an Append or MergeAppend.
2207 : *
2208 : * It's possible that the child is itself an Append or MergeAppend path, in
2209 : * which case we can "cut out the middleman" and just add its child paths to
2210 : * our own list. (We don't try to do this earlier because we need to apply
2211 : * both levels of transformation to the quals.)
2212 : *
2213 : * Note that if we omit a child MergeAppend in this way, we are effectively
2214 : * omitting a sort step, which seems fine: if the parent is to be an Append,
2215 : * its result would be unsorted anyway, while if the parent is to be a
2216 : * MergeAppend, there's no point in a separate sort on a child.
2217 : *
2218 : * Normally, either path is a partial path and subpaths is a list of partial
2219 : * paths, or else path is a non-partial plan and subpaths is a list of those.
2220 : * However, if path is a parallel-aware Append, then we add its partial path
2221 : * children to subpaths and the rest to special_subpaths. If the latter is
2222 : * NULL, we don't flatten the path at all (unless it contains only partial
2223 : * paths).
2224 : */
2225 : static void
2226 300442 : accumulate_append_subpath(Path *path, List **subpaths, List **special_subpaths)
2227 : {
2228 300442 : if (IsA(path, AppendPath))
2229 : {
2230 15404 : AppendPath *apath = (AppendPath *) path;
2231 :
2232 15404 : if (!apath->path.parallel_aware || apath->first_partial_path == 0)
2233 : {
2234 15068 : *subpaths = list_concat(*subpaths, apath->subpaths);
2235 15068 : return;
2236 : }
2237 336 : else if (special_subpaths != NULL)
2238 : {
2239 : List *new_special_subpaths;
2240 :
2241 : /* Split Parallel Append into partial and non-partial subpaths */
2242 168 : *subpaths = list_concat(*subpaths,
2243 168 : list_copy_tail(apath->subpaths,
2244 : apath->first_partial_path));
2245 168 : new_special_subpaths = list_copy_head(apath->subpaths,
2246 : apath->first_partial_path);
2247 168 : *special_subpaths = list_concat(*special_subpaths,
2248 : new_special_subpaths);
2249 168 : return;
2250 : }
2251 : }
2252 285038 : else if (IsA(path, MergeAppendPath))
2253 : {
2254 1076 : MergeAppendPath *mpath = (MergeAppendPath *) path;
2255 :
2256 1076 : *subpaths = list_concat(*subpaths, mpath->subpaths);
2257 1076 : return;
2258 : }
2259 :
2260 284130 : *subpaths = lappend(*subpaths, path);
2261 : }
2262 :
2263 : /*
2264 : * get_singleton_append_subpath
2265 : * Returns the single subpath of an Append/MergeAppend, or just
2266 : * return 'path' if it's not a single sub-path Append/MergeAppend.
2267 : *
2268 : * Note: 'path' must not be a parallel-aware path.
2269 : */
2270 : static Path *
2271 13096 : get_singleton_append_subpath(Path *path)
2272 : {
2273 : Assert(!path->parallel_aware);
2274 :
2275 13096 : if (IsA(path, AppendPath))
2276 : {
2277 388 : AppendPath *apath = (AppendPath *) path;
2278 :
2279 388 : if (list_length(apath->subpaths) == 1)
2280 192 : return (Path *) linitial(apath->subpaths);
2281 : }
2282 12708 : else if (IsA(path, MergeAppendPath))
2283 : {
2284 348 : MergeAppendPath *mpath = (MergeAppendPath *) path;
2285 :
2286 348 : if (list_length(mpath->subpaths) == 1)
2287 0 : return (Path *) linitial(mpath->subpaths);
2288 : }
2289 :
2290 12904 : return path;
2291 : }
2292 :
2293 : /*
2294 : * set_dummy_rel_pathlist
2295 : * Build a dummy path for a relation that's been excluded by constraints
2296 : *
2297 : * Rather than inventing a special "dummy" path type, we represent this as an
2298 : * AppendPath with no members (see also IS_DUMMY_APPEND/IS_DUMMY_REL macros).
2299 : *
2300 : * (See also mark_dummy_rel, which does basically the same thing, but is
2301 : * typically used to change a rel into dummy state after we already made
2302 : * paths for it.)
2303 : */
2304 : static void
2305 1304 : set_dummy_rel_pathlist(RelOptInfo *rel)
2306 : {
2307 : /* Set dummy size estimates --- we leave attr_widths[] as zeroes */
2308 1304 : rel->rows = 0;
2309 1304 : rel->reltarget->width = 0;
2310 :
2311 : /* Discard any pre-existing paths; no further need for them */
2312 1304 : rel->pathlist = NIL;
2313 1304 : rel->partial_pathlist = NIL;
2314 :
2315 : /* Set up the dummy path */
2316 1304 : add_path(rel, (Path *) create_append_path(NULL, rel, NIL, NIL,
2317 : NIL, rel->lateral_relids,
2318 : 0, false, -1));
2319 :
2320 : /*
2321 : * We set the cheapest-path fields immediately, just in case they were
2322 : * pointing at some discarded path. This is redundant in current usage
2323 : * because set_rel_pathlist will do it later, but it's cheap so we keep it
2324 : * for safety and consistency with mark_dummy_rel.
2325 : */
2326 1304 : set_cheapest(rel);
2327 1304 : }
2328 :
2329 : /*
2330 : * find_window_run_conditions
2331 : * Determine if 'wfunc' is really a WindowFunc and call its prosupport
2332 : * function to determine the function's monotonic properties. We then
2333 : * see if 'opexpr' can be used to short-circuit execution.
2334 : *
2335 : * For example row_number() over (order by ...) always produces a value one
2336 : * higher than the previous. If someone has a window function in a subquery
2337 : * and has a WHERE clause in the outer query to filter rows <= 10, then we may
2338 : * as well stop processing the windowagg once the row number reaches 11. Here
2339 : * we check if 'opexpr' might help us to stop doing needless extra processing
2340 : * in WindowAgg nodes.
2341 : *
2342 : * '*keep_original' is set to true if the caller should also use 'opexpr' for
2343 : * its original purpose. This is set to false if the caller can assume that
2344 : * the run condition will handle all of the required filtering.
2345 : *
2346 : * Returns true if 'opexpr' was found to be useful and was added to the
2347 : * WindowFunc's runCondition. We also set *keep_original accordingly and add
2348 : * 'attno' to *run_cond_attrs offset by FirstLowInvalidHeapAttributeNumber.
2349 : * If the 'opexpr' cannot be used then we set *keep_original to true and
2350 : * return false.
2351 : */
2352 : static bool
2353 240 : find_window_run_conditions(Query *subquery, AttrNumber attno,
2354 : WindowFunc *wfunc, OpExpr *opexpr, bool wfunc_left,
2355 : bool *keep_original, Bitmapset **run_cond_attrs)
2356 : {
2357 : Oid prosupport;
2358 : Expr *otherexpr;
2359 : SupportRequestWFuncMonotonic req;
2360 : SupportRequestWFuncMonotonic *res;
2361 : WindowClause *wclause;
2362 : List *opinfos;
2363 : OpExpr *runopexpr;
2364 : Oid runoperator;
2365 : ListCell *lc;
2366 :
2367 240 : *keep_original = true;
2368 :
2369 240 : while (IsA(wfunc, RelabelType))
2370 0 : wfunc = (WindowFunc *) ((RelabelType *) wfunc)->arg;
2371 :
2372 : /* we can only work with window functions */
2373 240 : if (!IsA(wfunc, WindowFunc))
2374 24 : return false;
2375 :
2376 : /* can't use it if there are subplans in the WindowFunc */
2377 216 : if (contain_subplans((Node *) wfunc))
2378 6 : return false;
2379 :
2380 210 : prosupport = get_func_support(wfunc->winfnoid);
2381 :
2382 : /* Check if there's a support function for 'wfunc' */
2383 210 : if (!OidIsValid(prosupport))
2384 18 : return false;
2385 :
2386 : /* get the Expr from the other side of the OpExpr */
2387 192 : if (wfunc_left)
2388 168 : otherexpr = lsecond(opexpr->args);
2389 : else
2390 24 : otherexpr = linitial(opexpr->args);
2391 :
2392 : /*
2393 : * The value being compared must not change during the evaluation of the
2394 : * window partition.
2395 : */
2396 192 : if (!is_pseudo_constant_clause((Node *) otherexpr))
2397 0 : return false;
2398 :
2399 : /* find the window clause belonging to the window function */
2400 192 : wclause = (WindowClause *) list_nth(subquery->windowClause,
2401 192 : wfunc->winref - 1);
2402 :
2403 192 : req.type = T_SupportRequestWFuncMonotonic;
2404 192 : req.window_func = wfunc;
2405 192 : req.window_clause = wclause;
2406 :
2407 : /* call the support function */
2408 : res = (SupportRequestWFuncMonotonic *)
2409 192 : DatumGetPointer(OidFunctionCall1(prosupport,
2410 : PointerGetDatum(&req)));
2411 :
2412 : /*
2413 : * Nothing to do if the function is neither monotonically increasing nor
2414 : * monotonically decreasing.
2415 : */
2416 192 : if (res == NULL || res->monotonic == MONOTONICFUNC_NONE)
2417 0 : return false;
2418 :
2419 192 : runopexpr = NULL;
2420 192 : runoperator = InvalidOid;
2421 192 : opinfos = get_op_index_interpretation(opexpr->opno);
2422 :
2423 192 : foreach(lc, opinfos)
2424 : {
2425 192 : OpIndexInterpretation *opinfo = (OpIndexInterpretation *) lfirst(lc);
2426 192 : CompareType cmptype = opinfo->cmptype;
2427 :
2428 : /* handle < / <= */
2429 192 : if (cmptype == COMPARE_LT || cmptype == COMPARE_LE)
2430 : {
2431 : /*
2432 : * < / <= is supported for monotonically increasing functions in
2433 : * the form <wfunc> op <pseudoconst> and <pseudoconst> op <wfunc>
2434 : * for monotonically decreasing functions.
2435 : */
2436 138 : if ((wfunc_left && (res->monotonic & MONOTONICFUNC_INCREASING)) ||
2437 18 : (!wfunc_left && (res->monotonic & MONOTONICFUNC_DECREASING)))
2438 : {
2439 126 : *keep_original = false;
2440 126 : runopexpr = opexpr;
2441 126 : runoperator = opexpr->opno;
2442 : }
2443 138 : break;
2444 : }
2445 : /* handle > / >= */
2446 54 : else if (cmptype == COMPARE_GT || cmptype == COMPARE_GE)
2447 : {
2448 : /*
2449 : * > / >= is supported for monotonically decreasing functions in
2450 : * the form <wfunc> op <pseudoconst> and <pseudoconst> op <wfunc>
2451 : * for monotonically increasing functions.
2452 : */
2453 18 : if ((wfunc_left && (res->monotonic & MONOTONICFUNC_DECREASING)) ||
2454 12 : (!wfunc_left && (res->monotonic & MONOTONICFUNC_INCREASING)))
2455 : {
2456 18 : *keep_original = false;
2457 18 : runopexpr = opexpr;
2458 18 : runoperator = opexpr->opno;
2459 : }
2460 18 : break;
2461 : }
2462 : /* handle = */
2463 36 : else if (cmptype == COMPARE_EQ)
2464 : {
2465 : CompareType newcmptype;
2466 :
2467 : /*
2468 : * When both monotonically increasing and decreasing then the
2469 : * return value of the window function will be the same each time.
2470 : * We can simply use 'opexpr' as the run condition without
2471 : * modifying it.
2472 : */
2473 36 : if ((res->monotonic & MONOTONICFUNC_BOTH) == MONOTONICFUNC_BOTH)
2474 : {
2475 6 : *keep_original = false;
2476 6 : runopexpr = opexpr;
2477 6 : runoperator = opexpr->opno;
2478 6 : break;
2479 : }
2480 :
2481 : /*
2482 : * When monotonically increasing we make a qual with <wfunc> <=
2483 : * <value> or <value> >= <wfunc> in order to filter out values
2484 : * which are above the value in the equality condition. For
2485 : * monotonically decreasing functions we want to filter values
2486 : * below the value in the equality condition.
2487 : */
2488 30 : if (res->monotonic & MONOTONICFUNC_INCREASING)
2489 30 : newcmptype = wfunc_left ? COMPARE_LE : COMPARE_GE;
2490 : else
2491 0 : newcmptype = wfunc_left ? COMPARE_GE : COMPARE_LE;
2492 :
2493 : /* We must keep the original equality qual */
2494 30 : *keep_original = true;
2495 30 : runopexpr = opexpr;
2496 :
2497 : /* determine the operator to use for the WindowFuncRunCondition */
2498 30 : runoperator = get_opfamily_member_for_cmptype(opinfo->opfamily_id,
2499 : opinfo->oplefttype,
2500 : opinfo->oprighttype,
2501 : newcmptype);
2502 30 : break;
2503 : }
2504 : }
2505 :
2506 192 : if (runopexpr != NULL)
2507 : {
2508 : WindowFuncRunCondition *wfuncrc;
2509 :
2510 180 : wfuncrc = makeNode(WindowFuncRunCondition);
2511 180 : wfuncrc->opno = runoperator;
2512 180 : wfuncrc->inputcollid = runopexpr->inputcollid;
2513 180 : wfuncrc->wfunc_left = wfunc_left;
2514 180 : wfuncrc->arg = copyObject(otherexpr);
2515 :
2516 180 : wfunc->runCondition = lappend(wfunc->runCondition, wfuncrc);
2517 :
2518 : /* record that this attno was used in a run condition */
2519 180 : *run_cond_attrs = bms_add_member(*run_cond_attrs,
2520 : attno - FirstLowInvalidHeapAttributeNumber);
2521 180 : return true;
2522 : }
2523 :
2524 : /* unsupported OpExpr */
2525 12 : return false;
2526 : }
2527 :
2528 : /*
2529 : * check_and_push_window_quals
2530 : * Check if 'clause' is a qual that can be pushed into a WindowFunc
2531 : * as a 'runCondition' qual. These, when present, allow some unnecessary
2532 : * work to be skipped during execution.
2533 : *
2534 : * 'run_cond_attrs' will be populated with all targetlist resnos of subquery
2535 : * targets (offset by FirstLowInvalidHeapAttributeNumber) that we pushed
2536 : * window quals for.
2537 : *
2538 : * Returns true if the caller still must keep the original qual or false if
2539 : * the caller can safely ignore the original qual because the WindowAgg node
2540 : * will use the runCondition to stop returning tuples.
2541 : */
2542 : static bool
2543 252 : check_and_push_window_quals(Query *subquery, Node *clause,
2544 : Bitmapset **run_cond_attrs)
2545 : {
2546 252 : OpExpr *opexpr = (OpExpr *) clause;
2547 252 : bool keep_original = true;
2548 : Var *var1;
2549 : Var *var2;
2550 :
2551 : /* We're only able to use OpExprs with 2 operands */
2552 252 : if (!IsA(opexpr, OpExpr))
2553 18 : return true;
2554 :
2555 234 : if (list_length(opexpr->args) != 2)
2556 0 : return true;
2557 :
2558 : /*
2559 : * Currently, we restrict this optimization to strict OpExprs. The reason
2560 : * for this is that during execution, once the runcondition becomes false,
2561 : * we stop evaluating WindowFuncs. To avoid leaving around stale window
2562 : * function result values, we set them to NULL. Having only strict
2563 : * OpExprs here ensures that we properly filter out the tuples with NULLs
2564 : * in the top-level WindowAgg.
2565 : */
2566 234 : set_opfuncid(opexpr);
2567 234 : if (!func_strict(opexpr->opfuncid))
2568 0 : return true;
2569 :
2570 : /*
2571 : * Check for plain Vars that reference window functions in the subquery.
2572 : * If we find any, we'll ask find_window_run_conditions() if 'opexpr' can
2573 : * be used as part of the run condition.
2574 : */
2575 :
2576 : /* Check the left side of the OpExpr */
2577 234 : var1 = linitial(opexpr->args);
2578 234 : if (IsA(var1, Var) && var1->varattno > 0)
2579 : {
2580 198 : TargetEntry *tle = list_nth(subquery->targetList, var1->varattno - 1);
2581 198 : WindowFunc *wfunc = (WindowFunc *) tle->expr;
2582 :
2583 198 : if (find_window_run_conditions(subquery, tle->resno, wfunc, opexpr,
2584 : true, &keep_original, run_cond_attrs))
2585 162 : return keep_original;
2586 : }
2587 :
2588 : /* and check the right side */
2589 72 : var2 = lsecond(opexpr->args);
2590 72 : if (IsA(var2, Var) && var2->varattno > 0)
2591 : {
2592 42 : TargetEntry *tle = list_nth(subquery->targetList, var2->varattno - 1);
2593 42 : WindowFunc *wfunc = (WindowFunc *) tle->expr;
2594 :
2595 42 : if (find_window_run_conditions(subquery, tle->resno, wfunc, opexpr,
2596 : false, &keep_original, run_cond_attrs))
2597 18 : return keep_original;
2598 : }
2599 :
2600 54 : return true;
2601 : }
2602 :
2603 : /*
2604 : * set_subquery_pathlist
2605 : * Generate SubqueryScan access paths for a subquery RTE
2606 : *
2607 : * We don't currently support generating parameterized paths for subqueries
2608 : * by pushing join clauses down into them; it seems too expensive to re-plan
2609 : * the subquery multiple times to consider different alternatives.
2610 : * (XXX that could stand to be reconsidered, now that we use Paths.)
2611 : * So the paths made here will be parameterized if the subquery contains
2612 : * LATERAL references, otherwise not. As long as that's true, there's no need
2613 : * for a separate set_subquery_size phase: just make the paths right away.
2614 : */
2615 : static void
2616 17532 : set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
2617 : Index rti, RangeTblEntry *rte)
2618 : {
2619 17532 : Query *parse = root->parse;
2620 17532 : Query *subquery = rte->subquery;
2621 : bool trivial_pathtarget;
2622 : Relids required_outer;
2623 : pushdown_safety_info safetyInfo;
2624 : double tuple_fraction;
2625 : RelOptInfo *sub_final_rel;
2626 17532 : Bitmapset *run_cond_attrs = NULL;
2627 : ListCell *lc;
2628 : char *plan_name;
2629 :
2630 : /*
2631 : * Must copy the Query so that planning doesn't mess up the RTE contents
2632 : * (really really need to fix the planner to not scribble on its input,
2633 : * someday ... but see remove_unused_subquery_outputs to start with).
2634 : */
2635 17532 : subquery = copyObject(subquery);
2636 :
2637 : /*
2638 : * If it's a LATERAL subquery, it might contain some Vars of the current
2639 : * query level, requiring it to be treated as parameterized, even though
2640 : * we don't support pushing down join quals into subqueries.
2641 : */
2642 17532 : required_outer = rel->lateral_relids;
2643 :
2644 : /*
2645 : * Zero out result area for subquery_is_pushdown_safe, so that it can set
2646 : * flags as needed while recursing. In particular, we need a workspace
2647 : * for keeping track of the reasons why columns are unsafe to reference.
2648 : * These reasons are stored in the bits inside unsafeFlags[i] when we
2649 : * discover reasons that column i of the subquery is unsafe to be used in
2650 : * a pushed-down qual.
2651 : */
2652 17532 : memset(&safetyInfo, 0, sizeof(safetyInfo));
2653 17532 : safetyInfo.unsafeFlags = (unsigned char *)
2654 17532 : palloc0((list_length(subquery->targetList) + 1) * sizeof(unsigned char));
2655 :
2656 : /*
2657 : * If the subquery has the "security_barrier" flag, it means the subquery
2658 : * originated from a view that must enforce row-level security. Then we
2659 : * must not push down quals that contain leaky functions. (Ideally this
2660 : * would be checked inside subquery_is_pushdown_safe, but since we don't
2661 : * currently pass the RTE to that function, we must do it here.)
2662 : */
2663 17532 : safetyInfo.unsafeLeaky = rte->security_barrier;
2664 :
2665 : /*
2666 : * If there are any restriction clauses that have been attached to the
2667 : * subquery relation, consider pushing them down to become WHERE or HAVING
2668 : * quals of the subquery itself. This transformation is useful because it
2669 : * may allow us to generate a better plan for the subquery than evaluating
2670 : * all the subquery output rows and then filtering them.
2671 : *
2672 : * There are several cases where we cannot push down clauses. Restrictions
2673 : * involving the subquery are checked by subquery_is_pushdown_safe().
2674 : * Restrictions on individual clauses are checked by
2675 : * qual_is_pushdown_safe(). Also, we don't want to push down
2676 : * pseudoconstant clauses; better to have the gating node above the
2677 : * subquery.
2678 : *
2679 : * Non-pushed-down clauses will get evaluated as qpquals of the
2680 : * SubqueryScan node.
2681 : *
2682 : * XXX Are there any cases where we want to make a policy decision not to
2683 : * push down a pushable qual, because it'd result in a worse plan?
2684 : */
2685 19492 : if (rel->baserestrictinfo != NIL &&
2686 1960 : subquery_is_pushdown_safe(subquery, subquery, &safetyInfo))
2687 : {
2688 : /* OK to consider pushing down individual quals */
2689 1814 : List *upperrestrictlist = NIL;
2690 : ListCell *l;
2691 :
2692 4580 : foreach(l, rel->baserestrictinfo)
2693 : {
2694 2766 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
2695 2766 : Node *clause = (Node *) rinfo->clause;
2696 :
2697 2766 : if (rinfo->pseudoconstant)
2698 : {
2699 4 : upperrestrictlist = lappend(upperrestrictlist, rinfo);
2700 4 : continue;
2701 : }
2702 :
2703 2762 : switch (qual_is_pushdown_safe(subquery, rti, rinfo, &safetyInfo))
2704 : {
2705 2056 : case PUSHDOWN_SAFE:
2706 : /* Push it down */
2707 2056 : subquery_push_qual(subquery, rte, rti, clause);
2708 2056 : break;
2709 :
2710 252 : case PUSHDOWN_WINDOWCLAUSE_RUNCOND:
2711 :
2712 : /*
2713 : * Since we can't push the qual down into the subquery,
2714 : * check if it happens to reference a window function. If
2715 : * so then it might be useful to use for the WindowAgg's
2716 : * runCondition.
2717 : */
2718 504 : if (!subquery->hasWindowFuncs ||
2719 252 : check_and_push_window_quals(subquery, clause,
2720 : &run_cond_attrs))
2721 : {
2722 : /*
2723 : * subquery has no window funcs or the clause is not a
2724 : * suitable window run condition qual or it is, but
2725 : * the original must also be kept in the upper query.
2726 : */
2727 102 : upperrestrictlist = lappend(upperrestrictlist, rinfo);
2728 : }
2729 252 : break;
2730 :
2731 454 : case PUSHDOWN_UNSAFE:
2732 454 : upperrestrictlist = lappend(upperrestrictlist, rinfo);
2733 454 : break;
2734 : }
2735 : }
2736 1814 : rel->baserestrictinfo = upperrestrictlist;
2737 : /* We don't bother recomputing baserestrict_min_security */
2738 : }
2739 :
2740 17532 : pfree(safetyInfo.unsafeFlags);
2741 :
2742 : /*
2743 : * The upper query might not use all the subquery's output columns; if
2744 : * not, we can simplify. Pass the attributes that were pushed down into
2745 : * WindowAgg run conditions to ensure we don't accidentally think those
2746 : * are unused.
2747 : */
2748 17532 : remove_unused_subquery_outputs(subquery, rel, run_cond_attrs);
2749 :
2750 : /*
2751 : * We can safely pass the outer tuple_fraction down to the subquery if the
2752 : * outer level has no joining, aggregation, or sorting to do. Otherwise
2753 : * we'd better tell the subquery to plan for full retrieval. (XXX This
2754 : * could probably be made more intelligent ...)
2755 : */
2756 17532 : if (parse->hasAggs ||
2757 16286 : parse->groupClause ||
2758 16268 : parse->groupingSets ||
2759 16268 : root->hasHavingQual ||
2760 16268 : parse->distinctClause ||
2761 22060 : parse->sortClause ||
2762 6308 : bms_membership(root->all_baserels) == BMS_MULTIPLE)
2763 12558 : tuple_fraction = 0.0; /* default case */
2764 : else
2765 4974 : tuple_fraction = root->tuple_fraction;
2766 :
2767 : /* plan_params should not be in use in current query level */
2768 : Assert(root->plan_params == NIL);
2769 :
2770 : /* Generate a subroot and Paths for the subquery */
2771 17532 : plan_name = choose_plan_name(root->glob, rte->eref->aliasname, false);
2772 17532 : rel->subroot = subquery_planner(root->glob, subquery, plan_name,
2773 : root, false, tuple_fraction, NULL);
2774 :
2775 : /* Isolate the params needed by this specific subplan */
2776 17532 : rel->subplan_params = root->plan_params;
2777 17532 : root->plan_params = NIL;
2778 :
2779 : /*
2780 : * It's possible that constraint exclusion proved the subquery empty. If
2781 : * so, it's desirable to produce an unadorned dummy path so that we will
2782 : * recognize appropriate optimizations at this query level.
2783 : */
2784 17532 : sub_final_rel = fetch_upper_rel(rel->subroot, UPPERREL_FINAL, NULL);
2785 :
2786 17532 : if (IS_DUMMY_REL(sub_final_rel))
2787 : {
2788 126 : set_dummy_rel_pathlist(rel);
2789 126 : return;
2790 : }
2791 :
2792 : /*
2793 : * Mark rel with estimated output rows, width, etc. Note that we have to
2794 : * do this before generating outer-query paths, else cost_subqueryscan is
2795 : * not happy.
2796 : */
2797 17406 : set_subquery_size_estimates(root, rel);
2798 :
2799 : /*
2800 : * Also detect whether the reltarget is trivial, so that we can pass that
2801 : * info to cost_subqueryscan (rather than re-deriving it multiple times).
2802 : * It's trivial if it fetches all the subplan output columns in order.
2803 : */
2804 17406 : if (list_length(rel->reltarget->exprs) != list_length(subquery->targetList))
2805 7714 : trivial_pathtarget = false;
2806 : else
2807 : {
2808 9692 : trivial_pathtarget = true;
2809 31640 : foreach(lc, rel->reltarget->exprs)
2810 : {
2811 22246 : Node *node = (Node *) lfirst(lc);
2812 : Var *var;
2813 :
2814 22246 : if (!IsA(node, Var))
2815 : {
2816 0 : trivial_pathtarget = false;
2817 0 : break;
2818 : }
2819 22246 : var = (Var *) node;
2820 22246 : if (var->varno != rti ||
2821 22246 : var->varattno != foreach_current_index(lc) + 1)
2822 : {
2823 298 : trivial_pathtarget = false;
2824 298 : break;
2825 : }
2826 : }
2827 : }
2828 :
2829 : /*
2830 : * For each Path that subquery_planner produced, make a SubqueryScanPath
2831 : * in the outer query.
2832 : */
2833 36836 : foreach(lc, sub_final_rel->pathlist)
2834 : {
2835 19430 : Path *subpath = (Path *) lfirst(lc);
2836 : List *pathkeys;
2837 :
2838 : /* Convert subpath's pathkeys to outer representation */
2839 19430 : pathkeys = convert_subquery_pathkeys(root,
2840 : rel,
2841 : subpath->pathkeys,
2842 : make_tlist_from_pathtarget(subpath->pathtarget));
2843 :
2844 : /* Generate outer path using this subpath */
2845 19430 : add_path(rel, (Path *)
2846 19430 : create_subqueryscan_path(root, rel, subpath,
2847 : trivial_pathtarget,
2848 : pathkeys, required_outer));
2849 : }
2850 :
2851 : /* If outer rel allows parallelism, do same for partial paths. */
2852 17406 : if (rel->consider_parallel && bms_is_empty(required_outer))
2853 : {
2854 : /* If consider_parallel is false, there should be no partial paths. */
2855 : Assert(sub_final_rel->consider_parallel ||
2856 : sub_final_rel->partial_pathlist == NIL);
2857 :
2858 : /* Same for partial paths. */
2859 13206 : foreach(lc, sub_final_rel->partial_pathlist)
2860 : {
2861 42 : Path *subpath = (Path *) lfirst(lc);
2862 : List *pathkeys;
2863 :
2864 : /* Convert subpath's pathkeys to outer representation */
2865 42 : pathkeys = convert_subquery_pathkeys(root,
2866 : rel,
2867 : subpath->pathkeys,
2868 : make_tlist_from_pathtarget(subpath->pathtarget));
2869 :
2870 : /* Generate outer path using this subpath */
2871 42 : add_partial_path(rel, (Path *)
2872 42 : create_subqueryscan_path(root, rel, subpath,
2873 : trivial_pathtarget,
2874 : pathkeys,
2875 : required_outer));
2876 : }
2877 : }
2878 : }
2879 :
2880 : /*
2881 : * set_function_pathlist
2882 : * Build the (single) access path for a function RTE
2883 : */
2884 : static void
2885 51798 : set_function_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
2886 : {
2887 : Relids required_outer;
2888 51798 : List *pathkeys = NIL;
2889 :
2890 : /*
2891 : * We don't support pushing join clauses into the quals of a function
2892 : * scan, but it could still have required parameterization due to LATERAL
2893 : * refs in the function expression.
2894 : */
2895 51798 : required_outer = rel->lateral_relids;
2896 :
2897 : /*
2898 : * The result is considered unordered unless ORDINALITY was used, in which
2899 : * case it is ordered by the ordinal column (the last one). See if we
2900 : * care, by checking for uses of that Var in equivalence classes.
2901 : */
2902 51798 : if (rte->funcordinality)
2903 : {
2904 922 : AttrNumber ordattno = rel->max_attr;
2905 922 : Var *var = NULL;
2906 : ListCell *lc;
2907 :
2908 : /*
2909 : * Is there a Var for it in rel's targetlist? If not, the query did
2910 : * not reference the ordinality column, or at least not in any way
2911 : * that would be interesting for sorting.
2912 : */
2913 2106 : foreach(lc, rel->reltarget->exprs)
2914 : {
2915 2100 : Var *node = (Var *) lfirst(lc);
2916 :
2917 : /* checking varno/varlevelsup is just paranoia */
2918 2100 : if (IsA(node, Var) &&
2919 2100 : node->varattno == ordattno &&
2920 916 : node->varno == rel->relid &&
2921 916 : node->varlevelsup == 0)
2922 : {
2923 916 : var = node;
2924 916 : break;
2925 : }
2926 : }
2927 :
2928 : /*
2929 : * Try to build pathkeys for this Var with int8 sorting. We tell
2930 : * build_expression_pathkey not to build any new equivalence class; if
2931 : * the Var isn't already mentioned in some EC, it means that nothing
2932 : * cares about the ordering.
2933 : */
2934 922 : if (var)
2935 916 : pathkeys = build_expression_pathkey(root,
2936 : (Expr *) var,
2937 : Int8LessOperator,
2938 : rel->relids,
2939 : false);
2940 : }
2941 :
2942 : /* Generate appropriate path */
2943 51798 : add_path(rel, create_functionscan_path(root, rel,
2944 : pathkeys, required_outer));
2945 51798 : }
2946 :
2947 : /*
2948 : * set_values_pathlist
2949 : * Build the (single) access path for a VALUES RTE
2950 : */
2951 : static void
2952 8294 : set_values_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
2953 : {
2954 : Relids required_outer;
2955 :
2956 : /*
2957 : * We don't support pushing join clauses into the quals of a values scan,
2958 : * but it could still have required parameterization due to LATERAL refs
2959 : * in the values expressions.
2960 : */
2961 8294 : required_outer = rel->lateral_relids;
2962 :
2963 : /* Generate appropriate path */
2964 8294 : add_path(rel, create_valuesscan_path(root, rel, required_outer));
2965 8294 : }
2966 :
2967 : /*
2968 : * set_tablefunc_pathlist
2969 : * Build the (single) access path for a table func RTE
2970 : */
2971 : static void
2972 626 : set_tablefunc_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
2973 : {
2974 : Relids required_outer;
2975 :
2976 : /*
2977 : * We don't support pushing join clauses into the quals of a tablefunc
2978 : * scan, but it could still have required parameterization due to LATERAL
2979 : * refs in the function expression.
2980 : */
2981 626 : required_outer = rel->lateral_relids;
2982 :
2983 : /* Generate appropriate path */
2984 626 : add_path(rel, create_tablefuncscan_path(root, rel,
2985 : required_outer));
2986 626 : }
2987 :
2988 : /*
2989 : * set_cte_pathlist
2990 : * Build the (single) access path for a non-self-reference CTE RTE
2991 : *
2992 : * There's no need for a separate set_cte_size phase, since we don't
2993 : * support join-qual-parameterized paths for CTEs.
2994 : */
2995 : static void
2996 4242 : set_cte_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
2997 : {
2998 : Path *ctepath;
2999 : Plan *cteplan;
3000 : PlannerInfo *cteroot;
3001 : Index levelsup;
3002 : List *pathkeys;
3003 : int ndx;
3004 : ListCell *lc;
3005 : int plan_id;
3006 : Relids required_outer;
3007 :
3008 : /*
3009 : * Find the referenced CTE, and locate the path and plan previously made
3010 : * for it.
3011 : */
3012 4242 : levelsup = rte->ctelevelsup;
3013 4242 : cteroot = root;
3014 7406 : while (levelsup-- > 0)
3015 : {
3016 3164 : cteroot = cteroot->parent_root;
3017 3164 : if (!cteroot) /* shouldn't happen */
3018 0 : elog(ERROR, "bad levelsup for CTE \"%s\"", rte->ctename);
3019 : }
3020 :
3021 : /*
3022 : * Note: cte_plan_ids can be shorter than cteList, if we are still working
3023 : * on planning the CTEs (ie, this is a side-reference from another CTE).
3024 : * So we mustn't use forboth here.
3025 : */
3026 4242 : ndx = 0;
3027 5824 : foreach(lc, cteroot->parse->cteList)
3028 : {
3029 5824 : CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
3030 :
3031 5824 : if (strcmp(cte->ctename, rte->ctename) == 0)
3032 4242 : break;
3033 1582 : ndx++;
3034 : }
3035 4242 : if (lc == NULL) /* shouldn't happen */
3036 0 : elog(ERROR, "could not find CTE \"%s\"", rte->ctename);
3037 4242 : if (ndx >= list_length(cteroot->cte_plan_ids))
3038 0 : elog(ERROR, "could not find plan for CTE \"%s\"", rte->ctename);
3039 4242 : plan_id = list_nth_int(cteroot->cte_plan_ids, ndx);
3040 4242 : if (plan_id <= 0)
3041 0 : elog(ERROR, "no plan was made for CTE \"%s\"", rte->ctename);
3042 :
3043 : Assert(list_length(root->glob->subpaths) == list_length(root->glob->subplans));
3044 4242 : ctepath = (Path *) list_nth(root->glob->subpaths, plan_id - 1);
3045 4242 : cteplan = (Plan *) list_nth(root->glob->subplans, plan_id - 1);
3046 :
3047 : /* Mark rel with estimated output rows, width, etc */
3048 4242 : set_cte_size_estimates(root, rel, cteplan->plan_rows);
3049 :
3050 : /* Convert the ctepath's pathkeys to outer query's representation */
3051 4242 : pathkeys = convert_subquery_pathkeys(root,
3052 : rel,
3053 : ctepath->pathkeys,
3054 : cteplan->targetlist);
3055 :
3056 : /*
3057 : * We don't support pushing join clauses into the quals of a CTE scan, but
3058 : * it could still have required parameterization due to LATERAL refs in
3059 : * its tlist.
3060 : */
3061 4242 : required_outer = rel->lateral_relids;
3062 :
3063 : /* Generate appropriate path */
3064 4242 : add_path(rel, create_ctescan_path(root, rel, pathkeys, required_outer));
3065 4242 : }
3066 :
3067 : /*
3068 : * set_namedtuplestore_pathlist
3069 : * Build the (single) access path for a named tuplestore RTE
3070 : *
3071 : * There's no need for a separate set_namedtuplestore_size phase, since we
3072 : * don't support join-qual-parameterized paths for tuplestores.
3073 : */
3074 : static void
3075 478 : set_namedtuplestore_pathlist(PlannerInfo *root, RelOptInfo *rel,
3076 : RangeTblEntry *rte)
3077 : {
3078 : Relids required_outer;
3079 :
3080 : /* Mark rel with estimated output rows, width, etc */
3081 478 : set_namedtuplestore_size_estimates(root, rel);
3082 :
3083 : /*
3084 : * We don't support pushing join clauses into the quals of a tuplestore
3085 : * scan, but it could still have required parameterization due to LATERAL
3086 : * refs in its tlist.
3087 : */
3088 478 : required_outer = rel->lateral_relids;
3089 :
3090 : /* Generate appropriate path */
3091 478 : add_path(rel, create_namedtuplestorescan_path(root, rel, required_outer));
3092 478 : }
3093 :
3094 : /*
3095 : * set_result_pathlist
3096 : * Build the (single) access path for an RTE_RESULT RTE
3097 : *
3098 : * There's no need for a separate set_result_size phase, since we
3099 : * don't support join-qual-parameterized paths for these RTEs.
3100 : */
3101 : static void
3102 4208 : set_result_pathlist(PlannerInfo *root, RelOptInfo *rel,
3103 : RangeTblEntry *rte)
3104 : {
3105 : Relids required_outer;
3106 :
3107 : /* Mark rel with estimated output rows, width, etc */
3108 4208 : set_result_size_estimates(root, rel);
3109 :
3110 : /*
3111 : * We don't support pushing join clauses into the quals of a Result scan,
3112 : * but it could still have required parameterization due to LATERAL refs
3113 : * in its tlist.
3114 : */
3115 4208 : required_outer = rel->lateral_relids;
3116 :
3117 : /* Generate appropriate path */
3118 4208 : add_path(rel, create_resultscan_path(root, rel, required_outer));
3119 4208 : }
3120 :
3121 : /*
3122 : * set_worktable_pathlist
3123 : * Build the (single) access path for a self-reference CTE RTE
3124 : *
3125 : * There's no need for a separate set_worktable_size phase, since we don't
3126 : * support join-qual-parameterized paths for CTEs.
3127 : */
3128 : static void
3129 934 : set_worktable_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
3130 : {
3131 : Path *ctepath;
3132 : PlannerInfo *cteroot;
3133 : Index levelsup;
3134 : Relids required_outer;
3135 :
3136 : /*
3137 : * We need to find the non-recursive term's path, which is in the plan
3138 : * level that's processing the recursive UNION, which is one level *below*
3139 : * where the CTE comes from.
3140 : */
3141 934 : levelsup = rte->ctelevelsup;
3142 934 : if (levelsup == 0) /* shouldn't happen */
3143 0 : elog(ERROR, "bad levelsup for CTE \"%s\"", rte->ctename);
3144 934 : levelsup--;
3145 934 : cteroot = root;
3146 2280 : while (levelsup-- > 0)
3147 : {
3148 1346 : cteroot = cteroot->parent_root;
3149 1346 : if (!cteroot) /* shouldn't happen */
3150 0 : elog(ERROR, "bad levelsup for CTE \"%s\"", rte->ctename);
3151 : }
3152 934 : ctepath = cteroot->non_recursive_path;
3153 934 : if (!ctepath) /* shouldn't happen */
3154 0 : elog(ERROR, "could not find path for CTE \"%s\"", rte->ctename);
3155 :
3156 : /* Mark rel with estimated output rows, width, etc */
3157 934 : set_cte_size_estimates(root, rel, ctepath->rows);
3158 :
3159 : /*
3160 : * We don't support pushing join clauses into the quals of a worktable
3161 : * scan, but it could still have required parameterization due to LATERAL
3162 : * refs in its tlist. (I'm not sure this is actually possible given the
3163 : * restrictions on recursive references, but it's easy enough to support.)
3164 : */
3165 934 : required_outer = rel->lateral_relids;
3166 :
3167 : /* Generate appropriate path */
3168 934 : add_path(rel, create_worktablescan_path(root, rel, required_outer));
3169 934 : }
3170 :
3171 : /*
3172 : * generate_gather_paths
3173 : * Generate parallel access paths for a relation by pushing a Gather or
3174 : * Gather Merge on top of a partial path.
3175 : *
3176 : * This must not be called until after we're done creating all partial paths
3177 : * for the specified relation. (Otherwise, add_partial_path might delete a
3178 : * path that some GatherPath or GatherMergePath has a reference to.)
3179 : *
3180 : * If we're generating paths for a scan or join relation, override_rows will
3181 : * be false, and we'll just use the relation's size estimate. When we're
3182 : * being called for a partially-grouped or partially-distinct path, though, we
3183 : * need to override the rowcount estimate. (It's not clear that the
3184 : * particular value we're using here is actually best, but the underlying rel
3185 : * has no estimate so we must do something.)
3186 : */
3187 : void
3188 24854 : generate_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_rows)
3189 : {
3190 : Path *cheapest_partial_path;
3191 : Path *simple_gather_path;
3192 : ListCell *lc;
3193 : double rows;
3194 24854 : double *rowsp = NULL;
3195 :
3196 : /* If there are no partial paths, there's nothing to do here. */
3197 24854 : if (rel->partial_pathlist == NIL)
3198 0 : return;
3199 :
3200 : /* Should we override the rel's rowcount estimate? */
3201 24854 : if (override_rows)
3202 6118 : rowsp = &rows;
3203 :
3204 : /*
3205 : * The output of Gather is always unsorted, so there's only one partial
3206 : * path of interest: the cheapest one. That will be the one at the front
3207 : * of partial_pathlist because of the way add_partial_path works.
3208 : */
3209 24854 : cheapest_partial_path = linitial(rel->partial_pathlist);
3210 24854 : rows = compute_gather_rows(cheapest_partial_path);
3211 : simple_gather_path = (Path *)
3212 24854 : create_gather_path(root, rel, cheapest_partial_path, rel->reltarget,
3213 : NULL, rowsp);
3214 24854 : add_path(rel, simple_gather_path);
3215 :
3216 : /*
3217 : * For each useful ordering, we can consider an order-preserving Gather
3218 : * Merge.
3219 : */
3220 55746 : foreach(lc, rel->partial_pathlist)
3221 : {
3222 30892 : Path *subpath = (Path *) lfirst(lc);
3223 : GatherMergePath *path;
3224 :
3225 30892 : if (subpath->pathkeys == NIL)
3226 24124 : continue;
3227 :
3228 6768 : rows = compute_gather_rows(subpath);
3229 6768 : path = create_gather_merge_path(root, rel, subpath, rel->reltarget,
3230 : subpath->pathkeys, NULL, rowsp);
3231 6768 : add_path(rel, &path->path);
3232 : }
3233 : }
3234 :
3235 : /*
3236 : * get_useful_pathkeys_for_relation
3237 : * Determine which orderings of a relation might be useful.
3238 : *
3239 : * Getting data in sorted order can be useful either because the requested
3240 : * order matches the final output ordering for the overall query we're
3241 : * planning, or because it enables an efficient merge join. Here, we try
3242 : * to figure out which pathkeys to consider.
3243 : *
3244 : * This allows us to do incremental sort on top of an index scan under a gather
3245 : * merge node, i.e. parallelized.
3246 : *
3247 : * If the require_parallel_safe is true, we also require the expressions to
3248 : * be parallel safe (which allows pushing the sort below Gather Merge).
3249 : *
3250 : * XXX At the moment this can only ever return a list with a single element,
3251 : * because it looks at query_pathkeys only. So we might return the pathkeys
3252 : * directly, but it seems plausible we'll want to consider other orderings
3253 : * in the future. For example, we might want to consider pathkeys useful for
3254 : * merge joins.
3255 : */
3256 : static List *
3257 24854 : get_useful_pathkeys_for_relation(PlannerInfo *root, RelOptInfo *rel,
3258 : bool require_parallel_safe)
3259 : {
3260 24854 : List *useful_pathkeys_list = NIL;
3261 :
3262 : /*
3263 : * Considering query_pathkeys is always worth it, because it might allow
3264 : * us to avoid a total sort when we have a partially presorted path
3265 : * available or to push the total sort into the parallel portion of the
3266 : * query.
3267 : */
3268 24854 : if (root->query_pathkeys)
3269 : {
3270 : ListCell *lc;
3271 14918 : int npathkeys = 0; /* useful pathkeys */
3272 :
3273 26062 : foreach(lc, root->query_pathkeys)
3274 : {
3275 18850 : PathKey *pathkey = (PathKey *) lfirst(lc);
3276 18850 : EquivalenceClass *pathkey_ec = pathkey->pk_eclass;
3277 :
3278 : /*
3279 : * We can only build a sort for pathkeys that contain a
3280 : * safe-to-compute-early EC member computable from the current
3281 : * relation's reltarget, so ignore the remainder of the list as
3282 : * soon as we find a pathkey without such a member.
3283 : *
3284 : * It's still worthwhile to return any prefix of the pathkeys list
3285 : * that meets this requirement, as we may be able to do an
3286 : * incremental sort.
3287 : *
3288 : * If requested, ensure the sort expression is parallel-safe too.
3289 : */
3290 18850 : if (!relation_can_be_sorted_early(root, rel, pathkey_ec,
3291 : require_parallel_safe))
3292 7706 : break;
3293 :
3294 11144 : npathkeys++;
3295 : }
3296 :
3297 : /*
3298 : * The whole query_pathkeys list matches, so append it directly, to
3299 : * allow comparing pathkeys easily by comparing list pointer. If we
3300 : * have to truncate the pathkeys, we gotta do a copy though.
3301 : */
3302 14918 : if (npathkeys == list_length(root->query_pathkeys))
3303 7212 : useful_pathkeys_list = lappend(useful_pathkeys_list,
3304 7212 : root->query_pathkeys);
3305 7706 : else if (npathkeys > 0)
3306 474 : useful_pathkeys_list = lappend(useful_pathkeys_list,
3307 474 : list_copy_head(root->query_pathkeys,
3308 : npathkeys));
3309 : }
3310 :
3311 24854 : return useful_pathkeys_list;
3312 : }
3313 :
3314 : /*
3315 : * generate_useful_gather_paths
3316 : * Generate parallel access paths for a relation by pushing a Gather or
3317 : * Gather Merge on top of a partial path.
3318 : *
3319 : * Unlike plain generate_gather_paths, this looks both at pathkeys of input
3320 : * paths (aiming to preserve the ordering), but also considers ordering that
3321 : * might be useful for nodes above the gather merge node, and tries to add
3322 : * a sort (regular or incremental) to provide that.
3323 : */
3324 : void
3325 616466 : generate_useful_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_rows)
3326 : {
3327 : ListCell *lc;
3328 : double rows;
3329 616466 : double *rowsp = NULL;
3330 616466 : List *useful_pathkeys_list = NIL;
3331 616466 : Path *cheapest_partial_path = NULL;
3332 :
3333 : /* If there are no partial paths, there's nothing to do here. */
3334 616466 : if (rel->partial_pathlist == NIL)
3335 591612 : return;
3336 :
3337 : /* Should we override the rel's rowcount estimate? */
3338 24854 : if (override_rows)
3339 6118 : rowsp = &rows;
3340 :
3341 : /* generate the regular gather (merge) paths */
3342 24854 : generate_gather_paths(root, rel, override_rows);
3343 :
3344 : /* consider incremental sort for interesting orderings */
3345 24854 : useful_pathkeys_list = get_useful_pathkeys_for_relation(root, rel, true);
3346 :
3347 : /* used for explicit (full) sort paths */
3348 24854 : cheapest_partial_path = linitial(rel->partial_pathlist);
3349 :
3350 : /*
3351 : * Consider sorted paths for each interesting ordering. We generate both
3352 : * incremental and full sort.
3353 : */
3354 32540 : foreach(lc, useful_pathkeys_list)
3355 : {
3356 7686 : List *useful_pathkeys = lfirst(lc);
3357 : ListCell *lc2;
3358 : bool is_sorted;
3359 : int presorted_keys;
3360 :
3361 18194 : foreach(lc2, rel->partial_pathlist)
3362 : {
3363 10508 : Path *subpath = (Path *) lfirst(lc2);
3364 : GatherMergePath *path;
3365 :
3366 10508 : is_sorted = pathkeys_count_contained_in(useful_pathkeys,
3367 : subpath->pathkeys,
3368 : &presorted_keys);
3369 :
3370 : /*
3371 : * We don't need to consider the case where a subpath is already
3372 : * fully sorted because generate_gather_paths already creates a
3373 : * gather merge path for every subpath that has pathkeys present.
3374 : *
3375 : * But since the subpath is already sorted, we know we don't need
3376 : * to consider adding a sort (full or incremental) on top of it,
3377 : * so we can continue here.
3378 : */
3379 10508 : if (is_sorted)
3380 2980 : continue;
3381 :
3382 : /*
3383 : * Try at least sorting the cheapest path and also try
3384 : * incrementally sorting any path which is partially sorted
3385 : * already (no need to deal with paths which have presorted keys
3386 : * when incremental sort is disabled unless it's the cheapest
3387 : * input path).
3388 : */
3389 7528 : if (subpath != cheapest_partial_path &&
3390 378 : (presorted_keys == 0 || !enable_incremental_sort))
3391 102 : continue;
3392 :
3393 : /*
3394 : * Consider regular sort for any path that's not presorted or if
3395 : * incremental sort is disabled. We've no need to consider both
3396 : * sort and incremental sort on the same path. We assume that
3397 : * incremental sort is always faster when there are presorted
3398 : * keys.
3399 : *
3400 : * This is not redundant with the gather paths created in
3401 : * generate_gather_paths, because that doesn't generate ordered
3402 : * output. Here we add an explicit sort to match the useful
3403 : * ordering.
3404 : */
3405 7426 : if (presorted_keys == 0 || !enable_incremental_sort)
3406 : {
3407 7138 : subpath = (Path *) create_sort_path(root,
3408 : rel,
3409 : subpath,
3410 : useful_pathkeys,
3411 : -1.0);
3412 : }
3413 : else
3414 288 : subpath = (Path *) create_incremental_sort_path(root,
3415 : rel,
3416 : subpath,
3417 : useful_pathkeys,
3418 : presorted_keys,
3419 : -1);
3420 7426 : rows = compute_gather_rows(subpath);
3421 7426 : path = create_gather_merge_path(root, rel,
3422 : subpath,
3423 7426 : rel->reltarget,
3424 : subpath->pathkeys,
3425 : NULL,
3426 : rowsp);
3427 :
3428 7426 : add_path(rel, &path->path);
3429 : }
3430 : }
3431 : }
3432 :
3433 : /*
3434 : * generate_grouped_paths
3435 : * Generate paths for a grouped relation by adding sorted and hashed
3436 : * partial aggregation paths on top of paths of the ungrouped relation.
3437 : *
3438 : * The information needed is provided by the RelAggInfo structure stored in
3439 : * "grouped_rel".
3440 : */
3441 : void
3442 898 : generate_grouped_paths(PlannerInfo *root, RelOptInfo *grouped_rel,
3443 : RelOptInfo *rel)
3444 : {
3445 898 : RelAggInfo *agg_info = grouped_rel->agg_info;
3446 : AggClauseCosts agg_costs;
3447 : bool can_hash;
3448 : bool can_sort;
3449 898 : Path *cheapest_total_path = NULL;
3450 898 : Path *cheapest_partial_path = NULL;
3451 898 : double dNumGroups = 0;
3452 898 : double dNumPartialGroups = 0;
3453 898 : List *group_pathkeys = NIL;
3454 :
3455 898 : if (IS_DUMMY_REL(rel))
3456 : {
3457 0 : mark_dummy_rel(grouped_rel);
3458 0 : return;
3459 : }
3460 :
3461 : /*
3462 : * We push partial aggregation only to the lowest possible level in the
3463 : * join tree that is deemed useful.
3464 : */
3465 898 : if (!bms_equal(agg_info->apply_agg_at, rel->relids) ||
3466 898 : !agg_info->agg_useful)
3467 0 : return;
3468 :
3469 5388 : MemSet(&agg_costs, 0, sizeof(AggClauseCosts));
3470 898 : get_agg_clause_costs(root, AGGSPLIT_INITIAL_SERIAL, &agg_costs);
3471 :
3472 : /*
3473 : * Determine whether it's possible to perform sort-based implementations
3474 : * of grouping, and generate the pathkeys that represent the grouping
3475 : * requirements in that case.
3476 : */
3477 898 : can_sort = grouping_is_sortable(agg_info->group_clauses);
3478 898 : if (can_sort)
3479 : {
3480 : RelOptInfo *top_grouped_rel;
3481 : List *top_group_tlist;
3482 :
3483 502 : top_grouped_rel = IS_OTHER_REL(rel) ?
3484 1400 : rel->top_parent->grouped_rel : grouped_rel;
3485 : top_group_tlist =
3486 898 : make_tlist_from_pathtarget(top_grouped_rel->agg_info->target);
3487 :
3488 : group_pathkeys =
3489 898 : make_pathkeys_for_sortclauses(root, agg_info->group_clauses,
3490 : top_group_tlist);
3491 : }
3492 :
3493 : /*
3494 : * Determine whether we should consider hash-based implementations of
3495 : * grouping.
3496 : */
3497 : Assert(root->numOrderedAggs == 0);
3498 1796 : can_hash = (agg_info->group_clauses != NIL &&
3499 898 : grouping_is_hashable(agg_info->group_clauses));
3500 :
3501 : /*
3502 : * Consider whether we should generate partially aggregated non-partial
3503 : * paths. We can only do this if we have a non-partial path.
3504 : */
3505 898 : if (rel->pathlist != NIL)
3506 : {
3507 898 : cheapest_total_path = rel->cheapest_total_path;
3508 : Assert(cheapest_total_path != NULL);
3509 : }
3510 :
3511 : /*
3512 : * If parallelism is possible for grouped_rel, then we should consider
3513 : * generating partially-grouped partial paths. However, if the ungrouped
3514 : * rel has no partial paths, then we can't.
3515 : */
3516 898 : if (grouped_rel->consider_parallel && rel->partial_pathlist != NIL)
3517 : {
3518 732 : cheapest_partial_path = linitial(rel->partial_pathlist);
3519 : Assert(cheapest_partial_path != NULL);
3520 : }
3521 :
3522 : /* Estimate number of partial groups. */
3523 898 : if (cheapest_total_path != NULL)
3524 898 : dNumGroups = estimate_num_groups(root,
3525 : agg_info->group_exprs,
3526 : cheapest_total_path->rows,
3527 : NULL, NULL);
3528 898 : if (cheapest_partial_path != NULL)
3529 732 : dNumPartialGroups = estimate_num_groups(root,
3530 : agg_info->group_exprs,
3531 : cheapest_partial_path->rows,
3532 : NULL, NULL);
3533 :
3534 898 : if (can_sort && cheapest_total_path != NULL)
3535 : {
3536 : ListCell *lc;
3537 :
3538 : /*
3539 : * Use any available suitably-sorted path as input, and also consider
3540 : * sorting the cheapest-total path and incremental sort on any paths
3541 : * with presorted keys.
3542 : *
3543 : * To save planning time, we ignore parameterized input paths unless
3544 : * they are the cheapest-total path.
3545 : */
3546 2174 : foreach(lc, rel->pathlist)
3547 : {
3548 1276 : Path *input_path = (Path *) lfirst(lc);
3549 : Path *path;
3550 : bool is_sorted;
3551 : int presorted_keys;
3552 :
3553 : /*
3554 : * Ignore parameterized paths that are not the cheapest-total
3555 : * path.
3556 : */
3557 1276 : if (input_path->param_info &&
3558 : input_path != cheapest_total_path)
3559 30 : continue;
3560 :
3561 1270 : is_sorted = pathkeys_count_contained_in(group_pathkeys,
3562 : input_path->pathkeys,
3563 : &presorted_keys);
3564 :
3565 : /*
3566 : * Ignore paths that are not suitably or partially sorted, unless
3567 : * they are the cheapest total path (no need to deal with paths
3568 : * which have presorted keys when incremental sort is disabled).
3569 : */
3570 1270 : if (!is_sorted && input_path != cheapest_total_path &&
3571 168 : (presorted_keys == 0 || !enable_incremental_sort))
3572 24 : continue;
3573 :
3574 : /*
3575 : * Since the path originates from a non-grouped relation that is
3576 : * not aware of eager aggregation, we must ensure that it provides
3577 : * the correct input for partial aggregation.
3578 : */
3579 1246 : path = (Path *) create_projection_path(root,
3580 : grouped_rel,
3581 : input_path,
3582 1246 : agg_info->agg_input);
3583 :
3584 1246 : if (!is_sorted)
3585 : {
3586 : /*
3587 : * We've no need to consider both a sort and incremental sort.
3588 : * We'll just do a sort if there are no presorted keys and an
3589 : * incremental sort when there are presorted keys.
3590 : */
3591 1036 : if (presorted_keys == 0 || !enable_incremental_sort)
3592 892 : path = (Path *) create_sort_path(root,
3593 : grouped_rel,
3594 : path,
3595 : group_pathkeys,
3596 : -1.0);
3597 : else
3598 144 : path = (Path *) create_incremental_sort_path(root,
3599 : grouped_rel,
3600 : path,
3601 : group_pathkeys,
3602 : presorted_keys,
3603 : -1.0);
3604 : }
3605 :
3606 : /*
3607 : * qual is NIL because the HAVING clause cannot be evaluated until
3608 : * the final value of the aggregate is known.
3609 : */
3610 1246 : path = (Path *) create_agg_path(root,
3611 : grouped_rel,
3612 : path,
3613 1246 : agg_info->target,
3614 : AGG_SORTED,
3615 : AGGSPLIT_INITIAL_SERIAL,
3616 : agg_info->group_clauses,
3617 : NIL,
3618 : &agg_costs,
3619 : dNumGroups);
3620 :
3621 1246 : add_path(grouped_rel, path);
3622 : }
3623 : }
3624 :
3625 898 : if (can_sort && cheapest_partial_path != NULL)
3626 : {
3627 : ListCell *lc;
3628 :
3629 : /* Similar to above logic, but for partial paths. */
3630 1704 : foreach(lc, rel->partial_pathlist)
3631 : {
3632 972 : Path *input_path = (Path *) lfirst(lc);
3633 : Path *path;
3634 : bool is_sorted;
3635 : int presorted_keys;
3636 :
3637 972 : is_sorted = pathkeys_count_contained_in(group_pathkeys,
3638 : input_path->pathkeys,
3639 : &presorted_keys);
3640 :
3641 : /*
3642 : * Ignore paths that are not suitably or partially sorted, unless
3643 : * they are the cheapest partial path (no need to deal with paths
3644 : * which have presorted keys when incremental sort is disabled).
3645 : */
3646 972 : if (!is_sorted && input_path != cheapest_partial_path &&
3647 96 : (presorted_keys == 0 || !enable_incremental_sort))
3648 0 : continue;
3649 :
3650 : /*
3651 : * Since the path originates from a non-grouped relation that is
3652 : * not aware of eager aggregation, we must ensure that it provides
3653 : * the correct input for partial aggregation.
3654 : */
3655 972 : path = (Path *) create_projection_path(root,
3656 : grouped_rel,
3657 : input_path,
3658 972 : agg_info->agg_input);
3659 :
3660 972 : if (!is_sorted)
3661 : {
3662 : /*
3663 : * We've no need to consider both a sort and incremental sort.
3664 : * We'll just do a sort if there are no presorted keys and an
3665 : * incremental sort when there are presorted keys.
3666 : */
3667 828 : if (presorted_keys == 0 || !enable_incremental_sort)
3668 732 : path = (Path *) create_sort_path(root,
3669 : grouped_rel,
3670 : path,
3671 : group_pathkeys,
3672 : -1.0);
3673 : else
3674 96 : path = (Path *) create_incremental_sort_path(root,
3675 : grouped_rel,
3676 : path,
3677 : group_pathkeys,
3678 : presorted_keys,
3679 : -1.0);
3680 : }
3681 :
3682 : /*
3683 : * qual is NIL because the HAVING clause cannot be evaluated until
3684 : * the final value of the aggregate is known.
3685 : */
3686 972 : path = (Path *) create_agg_path(root,
3687 : grouped_rel,
3688 : path,
3689 972 : agg_info->target,
3690 : AGG_SORTED,
3691 : AGGSPLIT_INITIAL_SERIAL,
3692 : agg_info->group_clauses,
3693 : NIL,
3694 : &agg_costs,
3695 : dNumPartialGroups);
3696 :
3697 972 : add_partial_path(grouped_rel, path);
3698 : }
3699 : }
3700 :
3701 : /*
3702 : * Add a partially-grouped HashAgg Path where possible
3703 : */
3704 898 : if (can_hash && cheapest_total_path != NULL)
3705 : {
3706 : Path *path;
3707 :
3708 : /*
3709 : * Since the path originates from a non-grouped relation that is not
3710 : * aware of eager aggregation, we must ensure that it provides the
3711 : * correct input for partial aggregation.
3712 : */
3713 898 : path = (Path *) create_projection_path(root,
3714 : grouped_rel,
3715 : cheapest_total_path,
3716 898 : agg_info->agg_input);
3717 :
3718 : /*
3719 : * qual is NIL because the HAVING clause cannot be evaluated until the
3720 : * final value of the aggregate is known.
3721 : */
3722 898 : path = (Path *) create_agg_path(root,
3723 : grouped_rel,
3724 : path,
3725 898 : agg_info->target,
3726 : AGG_HASHED,
3727 : AGGSPLIT_INITIAL_SERIAL,
3728 : agg_info->group_clauses,
3729 : NIL,
3730 : &agg_costs,
3731 : dNumGroups);
3732 :
3733 898 : add_path(grouped_rel, path);
3734 : }
3735 :
3736 : /*
3737 : * Now add a partially-grouped HashAgg partial Path where possible
3738 : */
3739 898 : if (can_hash && cheapest_partial_path != NULL)
3740 : {
3741 : Path *path;
3742 :
3743 : /*
3744 : * Since the path originates from a non-grouped relation that is not
3745 : * aware of eager aggregation, we must ensure that it provides the
3746 : * correct input for partial aggregation.
3747 : */
3748 732 : path = (Path *) create_projection_path(root,
3749 : grouped_rel,
3750 : cheapest_partial_path,
3751 732 : agg_info->agg_input);
3752 :
3753 : /*
3754 : * qual is NIL because the HAVING clause cannot be evaluated until the
3755 : * final value of the aggregate is known.
3756 : */
3757 732 : path = (Path *) create_agg_path(root,
3758 : grouped_rel,
3759 : path,
3760 732 : agg_info->target,
3761 : AGG_HASHED,
3762 : AGGSPLIT_INITIAL_SERIAL,
3763 : agg_info->group_clauses,
3764 : NIL,
3765 : &agg_costs,
3766 : dNumPartialGroups);
3767 :
3768 732 : add_partial_path(grouped_rel, path);
3769 : }
3770 : }
3771 :
3772 : /*
3773 : * make_rel_from_joinlist
3774 : * Build access paths using a "joinlist" to guide the join path search.
3775 : *
3776 : * See comments for deconstruct_jointree() for definition of the joinlist
3777 : * data structure.
3778 : */
3779 : static RelOptInfo *
3780 330018 : make_rel_from_joinlist(PlannerInfo *root, List *joinlist)
3781 : {
3782 : int levels_needed;
3783 : List *initial_rels;
3784 : ListCell *jl;
3785 :
3786 : /*
3787 : * Count the number of child joinlist nodes. This is the depth of the
3788 : * dynamic-programming algorithm we must employ to consider all ways of
3789 : * joining the child nodes.
3790 : */
3791 330018 : levels_needed = list_length(joinlist);
3792 :
3793 330018 : if (levels_needed <= 0)
3794 0 : return NULL; /* nothing to do? */
3795 :
3796 : /*
3797 : * Construct a list of rels corresponding to the child joinlist nodes.
3798 : * This may contain both base rels and rels constructed according to
3799 : * sub-joinlists.
3800 : */
3801 330018 : initial_rels = NIL;
3802 798594 : foreach(jl, joinlist)
3803 : {
3804 468576 : Node *jlnode = (Node *) lfirst(jl);
3805 : RelOptInfo *thisrel;
3806 :
3807 468576 : if (IsA(jlnode, RangeTblRef))
3808 : {
3809 465180 : int varno = ((RangeTblRef *) jlnode)->rtindex;
3810 :
3811 465180 : thisrel = find_base_rel(root, varno);
3812 : }
3813 3396 : else if (IsA(jlnode, List))
3814 : {
3815 : /* Recurse to handle subproblem */
3816 3396 : thisrel = make_rel_from_joinlist(root, (List *) jlnode);
3817 : }
3818 : else
3819 : {
3820 0 : elog(ERROR, "unrecognized joinlist node type: %d",
3821 : (int) nodeTag(jlnode));
3822 : thisrel = NULL; /* keep compiler quiet */
3823 : }
3824 :
3825 468576 : initial_rels = lappend(initial_rels, thisrel);
3826 : }
3827 :
3828 330018 : if (levels_needed == 1)
3829 : {
3830 : /*
3831 : * Single joinlist node, so we're done.
3832 : */
3833 229030 : return (RelOptInfo *) linitial(initial_rels);
3834 : }
3835 : else
3836 : {
3837 : /*
3838 : * Consider the different orders in which we could join the rels,
3839 : * using a plugin, GEQO, or the regular join search code.
3840 : *
3841 : * We put the initial_rels list into a PlannerInfo field because
3842 : * has_legal_joinclause() needs to look at it (ugly :-().
3843 : */
3844 100988 : root->initial_rels = initial_rels;
3845 :
3846 100988 : if (join_search_hook)
3847 0 : return (*join_search_hook) (root, levels_needed, initial_rels);
3848 100988 : else if (enable_geqo && levels_needed >= geqo_threshold)
3849 42 : return geqo(root, levels_needed, initial_rels);
3850 : else
3851 100946 : return standard_join_search(root, levels_needed, initial_rels);
3852 : }
3853 : }
3854 :
3855 : /*
3856 : * standard_join_search
3857 : * Find possible joinpaths for a query by successively finding ways
3858 : * to join component relations into join relations.
3859 : *
3860 : * 'levels_needed' is the number of iterations needed, ie, the number of
3861 : * independent jointree items in the query. This is > 1.
3862 : *
3863 : * 'initial_rels' is a list of RelOptInfo nodes for each independent
3864 : * jointree item. These are the components to be joined together.
3865 : * Note that levels_needed == list_length(initial_rels).
3866 : *
3867 : * Returns the final level of join relations, i.e., the relation that is
3868 : * the result of joining all the original relations together.
3869 : * At least one implementation path must be provided for this relation and
3870 : * all required sub-relations.
3871 : *
3872 : * To support loadable plugins that modify planner behavior by changing the
3873 : * join searching algorithm, we provide a hook variable that lets a plugin
3874 : * replace or supplement this function. Any such hook must return the same
3875 : * final join relation as the standard code would, but it might have a
3876 : * different set of implementation paths attached, and only the sub-joinrels
3877 : * needed for these paths need have been instantiated.
3878 : *
3879 : * Note to plugin authors: the functions invoked during standard_join_search()
3880 : * modify root->join_rel_list and root->join_rel_hash. If you want to do more
3881 : * than one join-order search, you'll probably need to save and restore the
3882 : * original states of those data structures. See geqo_eval() for an example.
3883 : */
3884 : RelOptInfo *
3885 100946 : standard_join_search(PlannerInfo *root, int levels_needed, List *initial_rels)
3886 : {
3887 : int lev;
3888 : RelOptInfo *rel;
3889 :
3890 : /*
3891 : * This function cannot be invoked recursively within any one planning
3892 : * problem, so join_rel_level[] can't be in use already.
3893 : */
3894 : Assert(root->join_rel_level == NULL);
3895 :
3896 : /*
3897 : * We employ a simple "dynamic programming" algorithm: we first find all
3898 : * ways to build joins of two jointree items, then all ways to build joins
3899 : * of three items (from two-item joins and single items), then four-item
3900 : * joins, and so on until we have considered all ways to join all the
3901 : * items into one rel.
3902 : *
3903 : * root->join_rel_level[j] is a list of all the j-item rels. Initially we
3904 : * set root->join_rel_level[1] to represent all the single-jointree-item
3905 : * relations.
3906 : */
3907 100946 : root->join_rel_level = (List **) palloc0((levels_needed + 1) * sizeof(List *));
3908 :
3909 100946 : root->join_rel_level[1] = initial_rels;
3910 :
3911 239444 : for (lev = 2; lev <= levels_needed; lev++)
3912 : {
3913 : ListCell *lc;
3914 :
3915 : /*
3916 : * Determine all possible pairs of relations to be joined at this
3917 : * level, and build paths for making each one from every available
3918 : * pair of lower-level relations.
3919 : */
3920 138498 : join_search_one_level(root, lev);
3921 :
3922 : /*
3923 : * Run generate_partitionwise_join_paths() and
3924 : * generate_useful_gather_paths() for each just-processed joinrel. We
3925 : * could not do this earlier because both regular and partial paths
3926 : * can get added to a particular joinrel at multiple times within
3927 : * join_search_one_level.
3928 : *
3929 : * After that, we're done creating paths for the joinrel, so run
3930 : * set_cheapest().
3931 : *
3932 : * In addition, we also run generate_grouped_paths() for the grouped
3933 : * relation of each just-processed joinrel, and run set_cheapest() for
3934 : * the grouped relation afterwards.
3935 : */
3936 350530 : foreach(lc, root->join_rel_level[lev])
3937 : {
3938 : bool is_top_rel;
3939 :
3940 212032 : rel = (RelOptInfo *) lfirst(lc);
3941 :
3942 212032 : is_top_rel = bms_equal(rel->relids, root->all_query_rels);
3943 :
3944 : /* Create paths for partitionwise joins. */
3945 212032 : generate_partitionwise_join_paths(root, rel);
3946 :
3947 : /*
3948 : * Except for the topmost scan/join rel, consider gathering
3949 : * partial paths. We'll do the same for the topmost scan/join rel
3950 : * once we know the final targetlist (see grouping_planner's and
3951 : * its call to apply_scanjoin_target_to_paths).
3952 : */
3953 212032 : if (!is_top_rel)
3954 111584 : generate_useful_gather_paths(root, rel, false);
3955 :
3956 : /* Find and save the cheapest paths for this rel */
3957 212032 : set_cheapest(rel);
3958 :
3959 : /*
3960 : * Except for the topmost scan/join rel, consider generating
3961 : * partial aggregation paths for the grouped relation on top of
3962 : * the paths of this rel. After that, we're done creating paths
3963 : * for the grouped relation, so run set_cheapest().
3964 : */
3965 212032 : if (rel->grouped_rel != NULL && !is_top_rel)
3966 : {
3967 72 : RelOptInfo *grouped_rel = rel->grouped_rel;
3968 :
3969 : Assert(IS_GROUPED_REL(grouped_rel));
3970 :
3971 72 : generate_grouped_paths(root, grouped_rel, rel);
3972 72 : set_cheapest(grouped_rel);
3973 : }
3974 :
3975 : #ifdef OPTIMIZER_DEBUG
3976 : pprint(rel);
3977 : #endif
3978 : }
3979 : }
3980 :
3981 : /*
3982 : * We should have a single rel at the final level.
3983 : */
3984 100946 : if (root->join_rel_level[levels_needed] == NIL)
3985 0 : elog(ERROR, "failed to build any %d-way joins", levels_needed);
3986 : Assert(list_length(root->join_rel_level[levels_needed]) == 1);
3987 :
3988 100946 : rel = (RelOptInfo *) linitial(root->join_rel_level[levels_needed]);
3989 :
3990 100946 : root->join_rel_level = NULL;
3991 :
3992 100946 : return rel;
3993 : }
3994 :
3995 : /*****************************************************************************
3996 : * PUSHING QUALS DOWN INTO SUBQUERIES
3997 : *****************************************************************************/
3998 :
3999 : /*
4000 : * subquery_is_pushdown_safe - is a subquery safe for pushing down quals?
4001 : *
4002 : * subquery is the particular component query being checked. topquery
4003 : * is the top component of a set-operations tree (the same Query if no
4004 : * set-op is involved).
4005 : *
4006 : * Conditions checked here:
4007 : *
4008 : * 1. If the subquery has a LIMIT clause, we must not push down any quals,
4009 : * since that could change the set of rows returned.
4010 : *
4011 : * 2. If the subquery contains EXCEPT or EXCEPT ALL set ops we cannot push
4012 : * quals into it, because that could change the results.
4013 : *
4014 : * 3. If the subquery uses DISTINCT, we cannot push volatile quals into it.
4015 : * This is because upper-level quals should semantically be evaluated only
4016 : * once per distinct row, not once per original row, and if the qual is
4017 : * volatile then extra evaluations could change the results. (This issue
4018 : * does not apply to other forms of aggregation such as GROUP BY, because
4019 : * when those are present we push into HAVING not WHERE, so that the quals
4020 : * are still applied after aggregation.)
4021 : *
4022 : * 4. If the subquery contains window functions, we cannot push volatile quals
4023 : * into it. The issue here is a bit different from DISTINCT: a volatile qual
4024 : * might succeed for some rows of a window partition and fail for others,
4025 : * thereby changing the partition contents and thus the window functions'
4026 : * results for rows that remain.
4027 : *
4028 : * 5. If the subquery contains any set-returning functions in its targetlist,
4029 : * we cannot push volatile quals into it. That would push them below the SRFs
4030 : * and thereby change the number of times they are evaluated. Also, a
4031 : * volatile qual could succeed for some SRF output rows and fail for others,
4032 : * a behavior that cannot occur if it's evaluated before SRF expansion.
4033 : *
4034 : * 6. If the subquery has nonempty grouping sets, we cannot push down any
4035 : * quals. The concern here is that a qual referencing a "constant" grouping
4036 : * column could get constant-folded, which would be improper because the value
4037 : * is potentially nullable by grouping-set expansion. This restriction could
4038 : * be removed if we had a parsetree representation that shows that such
4039 : * grouping columns are not really constant. (There are other ideas that
4040 : * could be used to relax this restriction, but that's the approach most
4041 : * likely to get taken in the future. Note that there's not much to be gained
4042 : * so long as subquery_planner can't move HAVING clauses to WHERE within such
4043 : * a subquery.)
4044 : *
4045 : * In addition, we make several checks on the subquery's output columns to see
4046 : * if it is safe to reference them in pushed-down quals. If output column k
4047 : * is found to be unsafe to reference, we set the reason for that inside
4048 : * safetyInfo->unsafeFlags[k], but we don't reject the subquery overall since
4049 : * column k might not be referenced by some/all quals. The unsafeFlags[]
4050 : * array will be consulted later by qual_is_pushdown_safe(). It's better to
4051 : * do it this way than to make the checks directly in qual_is_pushdown_safe(),
4052 : * because when the subquery involves set operations we have to check the
4053 : * output expressions in each arm of the set op.
4054 : *
4055 : * Note: pushing quals into a DISTINCT subquery is theoretically dubious:
4056 : * we're effectively assuming that the quals cannot distinguish values that
4057 : * the DISTINCT's equality operator sees as equal, yet there are many
4058 : * counterexamples to that assumption. However use of such a qual with a
4059 : * DISTINCT subquery would be unsafe anyway, since there's no guarantee which
4060 : * "equal" value will be chosen as the output value by the DISTINCT operation.
4061 : * So we don't worry too much about that. Another objection is that if the
4062 : * qual is expensive to evaluate, running it for each original row might cost
4063 : * more than we save by eliminating rows before the DISTINCT step. But it
4064 : * would be very hard to estimate that at this stage, and in practice pushdown
4065 : * seldom seems to make things worse, so we ignore that problem too.
4066 : *
4067 : * Note: likewise, pushing quals into a subquery with window functions is a
4068 : * bit dubious: the quals might remove some rows of a window partition while
4069 : * leaving others, causing changes in the window functions' results for the
4070 : * surviving rows. We insist that such a qual reference only partitioning
4071 : * columns, but again that only protects us if the qual does not distinguish
4072 : * values that the partitioning equality operator sees as equal. The risks
4073 : * here are perhaps larger than for DISTINCT, since no de-duplication of rows
4074 : * occurs and thus there is no theoretical problem with such a qual. But
4075 : * we'll do this anyway because the potential performance benefits are very
4076 : * large, and we've seen no field complaints about the longstanding comparable
4077 : * behavior with DISTINCT.
4078 : */
4079 : static bool
4080 2272 : subquery_is_pushdown_safe(Query *subquery, Query *topquery,
4081 : pushdown_safety_info *safetyInfo)
4082 : {
4083 : SetOperationStmt *topop;
4084 :
4085 : /* Check point 1 */
4086 2272 : if (subquery->limitOffset != NULL || subquery->limitCount != NULL)
4087 134 : return false;
4088 :
4089 : /* Check point 6 */
4090 2138 : if (subquery->groupClause && subquery->groupingSets)
4091 12 : return false;
4092 :
4093 : /* Check points 3, 4, and 5 */
4094 2126 : if (subquery->distinctClause ||
4095 2042 : subquery->hasWindowFuncs ||
4096 1776 : subquery->hasTargetSRFs)
4097 546 : safetyInfo->unsafeVolatile = true;
4098 :
4099 : /*
4100 : * If we're at a leaf query, check for unsafe expressions in its target
4101 : * list, and mark any reasons why they're unsafe in unsafeFlags[].
4102 : * (Non-leaf nodes in setop trees have only simple Vars in their tlists,
4103 : * so no need to check them.)
4104 : */
4105 2126 : if (subquery->setOperations == NULL)
4106 1970 : check_output_expressions(subquery, safetyInfo);
4107 :
4108 : /* Are we at top level, or looking at a setop component? */
4109 2126 : if (subquery == topquery)
4110 : {
4111 : /* Top level, so check any component queries */
4112 1814 : if (subquery->setOperations != NULL)
4113 156 : if (!recurse_pushdown_safe(subquery->setOperations, topquery,
4114 : safetyInfo))
4115 0 : return false;
4116 : }
4117 : else
4118 : {
4119 : /* Setop component must not have more components (too weird) */
4120 312 : if (subquery->setOperations != NULL)
4121 0 : return false;
4122 : /* Check whether setop component output types match top level */
4123 312 : topop = castNode(SetOperationStmt, topquery->setOperations);
4124 : Assert(topop);
4125 312 : compare_tlist_datatypes(subquery->targetList,
4126 : topop->colTypes,
4127 : safetyInfo);
4128 : }
4129 2126 : return true;
4130 : }
4131 :
4132 : /*
4133 : * Helper routine to recurse through setOperations tree
4134 : */
4135 : static bool
4136 468 : recurse_pushdown_safe(Node *setOp, Query *topquery,
4137 : pushdown_safety_info *safetyInfo)
4138 : {
4139 468 : if (IsA(setOp, RangeTblRef))
4140 : {
4141 312 : RangeTblRef *rtr = (RangeTblRef *) setOp;
4142 312 : RangeTblEntry *rte = rt_fetch(rtr->rtindex, topquery->rtable);
4143 312 : Query *subquery = rte->subquery;
4144 :
4145 : Assert(subquery != NULL);
4146 312 : return subquery_is_pushdown_safe(subquery, topquery, safetyInfo);
4147 : }
4148 156 : else if (IsA(setOp, SetOperationStmt))
4149 : {
4150 156 : SetOperationStmt *op = (SetOperationStmt *) setOp;
4151 :
4152 : /* EXCEPT is no good (point 2 for subquery_is_pushdown_safe) */
4153 156 : if (op->op == SETOP_EXCEPT)
4154 0 : return false;
4155 : /* Else recurse */
4156 156 : if (!recurse_pushdown_safe(op->larg, topquery, safetyInfo))
4157 0 : return false;
4158 156 : if (!recurse_pushdown_safe(op->rarg, topquery, safetyInfo))
4159 0 : return false;
4160 : }
4161 : else
4162 : {
4163 0 : elog(ERROR, "unrecognized node type: %d",
4164 : (int) nodeTag(setOp));
4165 : }
4166 156 : return true;
4167 : }
4168 :
4169 : /*
4170 : * check_output_expressions - check subquery's output expressions for safety
4171 : *
4172 : * There are several cases in which it's unsafe to push down an upper-level
4173 : * qual if it references a particular output column of a subquery. We check
4174 : * each output column of the subquery and set flags in unsafeFlags[k] when we
4175 : * see that column is unsafe for a pushed-down qual to reference. The
4176 : * conditions checked here are:
4177 : *
4178 : * 1. We must not push down any quals that refer to subselect outputs that
4179 : * return sets, else we'd introduce functions-returning-sets into the
4180 : * subquery's WHERE/HAVING quals.
4181 : *
4182 : * 2. We must not push down any quals that refer to subselect outputs that
4183 : * contain volatile functions, for fear of introducing strange results due
4184 : * to multiple evaluation of a volatile function.
4185 : *
4186 : * 3. If the subquery uses DISTINCT ON, we must not push down any quals that
4187 : * refer to non-DISTINCT output columns, because that could change the set
4188 : * of rows returned. (This condition is vacuous for DISTINCT, because then
4189 : * there are no non-DISTINCT output columns, so we needn't check. Note that
4190 : * subquery_is_pushdown_safe already reported that we can't use volatile
4191 : * quals if there's DISTINCT or DISTINCT ON.)
4192 : *
4193 : * 4. If the subquery has any window functions, we must not push down quals
4194 : * that reference any output columns that are not listed in all the subquery's
4195 : * window PARTITION BY clauses. We can push down quals that use only
4196 : * partitioning columns because they should succeed or fail identically for
4197 : * every row of any one window partition, and totally excluding some
4198 : * partitions will not change a window function's results for remaining
4199 : * partitions. (Again, this also requires nonvolatile quals, but
4200 : * subquery_is_pushdown_safe handles that.). Subquery columns marked as
4201 : * unsafe for this reason can still have WindowClause run conditions pushed
4202 : * down.
4203 : */
4204 : static void
4205 1970 : check_output_expressions(Query *subquery, pushdown_safety_info *safetyInfo)
4206 : {
4207 : ListCell *lc;
4208 :
4209 21106 : foreach(lc, subquery->targetList)
4210 : {
4211 19136 : TargetEntry *tle = (TargetEntry *) lfirst(lc);
4212 :
4213 19136 : if (tle->resjunk)
4214 134 : continue; /* ignore resjunk columns */
4215 :
4216 : /* Functions returning sets are unsafe (point 1) */
4217 19002 : if (subquery->hasTargetSRFs &&
4218 668 : (safetyInfo->unsafeFlags[tle->resno] &
4219 668 : UNSAFE_HAS_SET_FUNC) == 0 &&
4220 668 : expression_returns_set((Node *) tle->expr))
4221 : {
4222 376 : safetyInfo->unsafeFlags[tle->resno] |= UNSAFE_HAS_SET_FUNC;
4223 376 : continue;
4224 : }
4225 :
4226 : /* Volatile functions are unsafe (point 2) */
4227 18626 : if ((safetyInfo->unsafeFlags[tle->resno] &
4228 18614 : UNSAFE_HAS_VOLATILE_FUNC) == 0 &&
4229 18614 : contain_volatile_functions((Node *) tle->expr))
4230 : {
4231 78 : safetyInfo->unsafeFlags[tle->resno] |= UNSAFE_HAS_VOLATILE_FUNC;
4232 78 : continue;
4233 : }
4234 :
4235 : /* If subquery uses DISTINCT ON, check point 3 */
4236 18548 : if (subquery->hasDistinctOn &&
4237 0 : (safetyInfo->unsafeFlags[tle->resno] &
4238 0 : UNSAFE_NOTIN_DISTINCTON_CLAUSE) == 0 &&
4239 0 : !targetIsInSortList(tle, InvalidOid, subquery->distinctClause))
4240 : {
4241 : /* non-DISTINCT column, so mark it unsafe */
4242 0 : safetyInfo->unsafeFlags[tle->resno] |= UNSAFE_NOTIN_DISTINCTON_CLAUSE;
4243 0 : continue;
4244 : }
4245 :
4246 : /* If subquery uses window functions, check point 4 */
4247 18548 : if (subquery->hasWindowFuncs &&
4248 1090 : (safetyInfo->unsafeFlags[tle->resno] &
4249 2092 : UNSAFE_NOTIN_DISTINCTON_CLAUSE) == 0 &&
4250 1090 : !targetIsInAllPartitionLists(tle, subquery))
4251 : {
4252 : /* not present in all PARTITION BY clauses, so mark it unsafe */
4253 1002 : safetyInfo->unsafeFlags[tle->resno] |= UNSAFE_NOTIN_PARTITIONBY_CLAUSE;
4254 1002 : continue;
4255 : }
4256 : }
4257 1970 : }
4258 :
4259 : /*
4260 : * For subqueries using UNION/UNION ALL/INTERSECT/INTERSECT ALL, we can
4261 : * push quals into each component query, but the quals can only reference
4262 : * subquery columns that suffer no type coercions in the set operation.
4263 : * Otherwise there are possible semantic gotchas. So, we check the
4264 : * component queries to see if any of them have output types different from
4265 : * the top-level setop outputs. We set the UNSAFE_TYPE_MISMATCH bit in
4266 : * unsafeFlags[k] if column k has different type in any component.
4267 : *
4268 : * We don't have to care about typmods here: the only allowed difference
4269 : * between set-op input and output typmods is input is a specific typmod
4270 : * and output is -1, and that does not require a coercion.
4271 : *
4272 : * tlist is a subquery tlist.
4273 : * colTypes is an OID list of the top-level setop's output column types.
4274 : * safetyInfo is the pushdown_safety_info to set unsafeFlags[] for.
4275 : */
4276 : static void
4277 312 : compare_tlist_datatypes(List *tlist, List *colTypes,
4278 : pushdown_safety_info *safetyInfo)
4279 : {
4280 : ListCell *l;
4281 312 : ListCell *colType = list_head(colTypes);
4282 :
4283 984 : foreach(l, tlist)
4284 : {
4285 672 : TargetEntry *tle = (TargetEntry *) lfirst(l);
4286 :
4287 672 : if (tle->resjunk)
4288 0 : continue; /* ignore resjunk columns */
4289 672 : if (colType == NULL)
4290 0 : elog(ERROR, "wrong number of tlist entries");
4291 672 : if (exprType((Node *) tle->expr) != lfirst_oid(colType))
4292 104 : safetyInfo->unsafeFlags[tle->resno] |= UNSAFE_TYPE_MISMATCH;
4293 672 : colType = lnext(colTypes, colType);
4294 : }
4295 312 : if (colType != NULL)
4296 0 : elog(ERROR, "wrong number of tlist entries");
4297 312 : }
4298 :
4299 : /*
4300 : * targetIsInAllPartitionLists
4301 : * True if the TargetEntry is listed in the PARTITION BY clause
4302 : * of every window defined in the query.
4303 : *
4304 : * It would be safe to ignore windows not actually used by any window
4305 : * function, but it's not easy to get that info at this stage; and it's
4306 : * unlikely to be useful to spend any extra cycles getting it, since
4307 : * unreferenced window definitions are probably infrequent in practice.
4308 : */
4309 : static bool
4310 1090 : targetIsInAllPartitionLists(TargetEntry *tle, Query *query)
4311 : {
4312 : ListCell *lc;
4313 :
4314 1202 : foreach(lc, query->windowClause)
4315 : {
4316 1114 : WindowClause *wc = (WindowClause *) lfirst(lc);
4317 :
4318 1114 : if (!targetIsInSortList(tle, InvalidOid, wc->partitionClause))
4319 1002 : return false;
4320 : }
4321 88 : return true;
4322 : }
4323 :
4324 : /*
4325 : * qual_is_pushdown_safe - is a particular rinfo safe to push down?
4326 : *
4327 : * rinfo is a restriction clause applying to the given subquery (whose RTE
4328 : * has index rti in the parent query).
4329 : *
4330 : * Conditions checked here:
4331 : *
4332 : * 1. rinfo's clause must not contain any SubPlans (mainly because it's
4333 : * unclear that it will work correctly: SubLinks will already have been
4334 : * transformed into SubPlans in the qual, but not in the subquery). Note that
4335 : * SubLinks that transform to initplans are safe, and will be accepted here
4336 : * because what we'll see in the qual is just a Param referencing the initplan
4337 : * output.
4338 : *
4339 : * 2. If unsafeVolatile is set, rinfo's clause must not contain any volatile
4340 : * functions.
4341 : *
4342 : * 3. If unsafeLeaky is set, rinfo's clause must not contain any leaky
4343 : * functions that are passed Var nodes, and therefore might reveal values from
4344 : * the subquery as side effects.
4345 : *
4346 : * 4. rinfo's clause must not refer to the whole-row output of the subquery
4347 : * (since there is no easy way to name that within the subquery itself).
4348 : *
4349 : * 5. rinfo's clause must not refer to any subquery output columns that were
4350 : * found to be unsafe to reference by subquery_is_pushdown_safe().
4351 : */
4352 : static pushdown_safe_type
4353 2762 : qual_is_pushdown_safe(Query *subquery, Index rti, RestrictInfo *rinfo,
4354 : pushdown_safety_info *safetyInfo)
4355 : {
4356 2762 : pushdown_safe_type safe = PUSHDOWN_SAFE;
4357 2762 : Node *qual = (Node *) rinfo->clause;
4358 : List *vars;
4359 : ListCell *vl;
4360 :
4361 : /* Refuse subselects (point 1) */
4362 2762 : if (contain_subplans(qual))
4363 66 : return PUSHDOWN_UNSAFE;
4364 :
4365 : /* Refuse volatile quals if we found they'd be unsafe (point 2) */
4366 3348 : if (safetyInfo->unsafeVolatile &&
4367 652 : contain_volatile_functions((Node *) rinfo))
4368 18 : return PUSHDOWN_UNSAFE;
4369 :
4370 : /* Refuse leaky quals if told to (point 3) */
4371 3850 : if (safetyInfo->unsafeLeaky &&
4372 1172 : contain_leaked_vars(qual))
4373 162 : return PUSHDOWN_UNSAFE;
4374 :
4375 : /*
4376 : * Examine all Vars used in clause. Since it's a restriction clause, all
4377 : * such Vars must refer to subselect output columns ... unless this is
4378 : * part of a LATERAL subquery, in which case there could be lateral
4379 : * references.
4380 : *
4381 : * By omitting the relevant flags, this also gives us a cheap sanity check
4382 : * that no aggregates or window functions appear in the qual. Those would
4383 : * be unsafe to push down, but at least for the moment we could never see
4384 : * any in a qual anyhow.
4385 : */
4386 2516 : vars = pull_var_clause(qual, PVC_INCLUDE_PLACEHOLDERS);
4387 4932 : foreach(vl, vars)
4388 : {
4389 2624 : Var *var = (Var *) lfirst(vl);
4390 :
4391 : /*
4392 : * XXX Punt if we find any PlaceHolderVars in the restriction clause.
4393 : * It's not clear whether a PHV could safely be pushed down, and even
4394 : * less clear whether such a situation could arise in any cases of
4395 : * practical interest anyway. So for the moment, just refuse to push
4396 : * down.
4397 : */
4398 2624 : if (!IsA(var, Var))
4399 : {
4400 0 : safe = PUSHDOWN_UNSAFE;
4401 0 : break;
4402 : }
4403 :
4404 : /*
4405 : * Punt if we find any lateral references. It would be safe to push
4406 : * these down, but we'd have to convert them into outer references,
4407 : * which subquery_push_qual lacks the infrastructure to do. The case
4408 : * arises so seldom that it doesn't seem worth working hard on.
4409 : */
4410 2624 : if (var->varno != rti)
4411 : {
4412 12 : safe = PUSHDOWN_UNSAFE;
4413 12 : break;
4414 : }
4415 :
4416 : /* Subqueries have no system columns */
4417 : Assert(var->varattno >= 0);
4418 :
4419 : /* Check point 4 */
4420 2612 : if (var->varattno == 0)
4421 : {
4422 0 : safe = PUSHDOWN_UNSAFE;
4423 0 : break;
4424 : }
4425 :
4426 : /* Check point 5 */
4427 2612 : if (safetyInfo->unsafeFlags[var->varattno] != 0)
4428 : {
4429 526 : if (safetyInfo->unsafeFlags[var->varattno] &
4430 : (UNSAFE_HAS_VOLATILE_FUNC | UNSAFE_HAS_SET_FUNC |
4431 : UNSAFE_NOTIN_DISTINCTON_CLAUSE | UNSAFE_TYPE_MISMATCH))
4432 : {
4433 196 : safe = PUSHDOWN_UNSAFE;
4434 196 : break;
4435 : }
4436 : else
4437 : {
4438 : /* UNSAFE_NOTIN_PARTITIONBY_CLAUSE is ok for run conditions */
4439 330 : safe = PUSHDOWN_WINDOWCLAUSE_RUNCOND;
4440 : /* don't break, we might find another Var that's unsafe */
4441 : }
4442 : }
4443 : }
4444 :
4445 2516 : list_free(vars);
4446 :
4447 2516 : return safe;
4448 : }
4449 :
4450 : /*
4451 : * subquery_push_qual - push down a qual that we have determined is safe
4452 : */
4453 : static void
4454 2320 : subquery_push_qual(Query *subquery, RangeTblEntry *rte, Index rti, Node *qual)
4455 : {
4456 2320 : if (subquery->setOperations != NULL)
4457 : {
4458 : /* Recurse to push it separately to each component query */
4459 132 : recurse_push_qual(subquery->setOperations, subquery,
4460 : rte, rti, qual);
4461 : }
4462 : else
4463 : {
4464 : /*
4465 : * We need to replace Vars in the qual (which must refer to outputs of
4466 : * the subquery) with copies of the subquery's targetlist expressions.
4467 : * Note that at this point, any uplevel Vars in the qual should have
4468 : * been replaced with Params, so they need no work.
4469 : *
4470 : * This step also ensures that when we are pushing into a setop tree,
4471 : * each component query gets its own copy of the qual.
4472 : */
4473 2188 : qual = ReplaceVarsFromTargetList(qual, rti, 0, rte,
4474 : subquery->targetList,
4475 : subquery->resultRelation,
4476 : REPLACEVARS_REPORT_ERROR, 0,
4477 : &subquery->hasSubLinks);
4478 :
4479 : /*
4480 : * Now attach the qual to the proper place: normally WHERE, but if the
4481 : * subquery uses grouping or aggregation, put it in HAVING (since the
4482 : * qual really refers to the group-result rows).
4483 : */
4484 2188 : if (subquery->hasAggs || subquery->groupClause || subquery->groupingSets || subquery->havingQual)
4485 380 : subquery->havingQual = make_and_qual(subquery->havingQual, qual);
4486 : else
4487 1808 : subquery->jointree->quals =
4488 1808 : make_and_qual(subquery->jointree->quals, qual);
4489 :
4490 : /*
4491 : * We need not change the subquery's hasAggs or hasSubLinks flags,
4492 : * since we can't be pushing down any aggregates that weren't there
4493 : * before, and we don't push down subselects at all.
4494 : */
4495 : }
4496 2320 : }
4497 :
4498 : /*
4499 : * Helper routine to recurse through setOperations tree
4500 : */
4501 : static void
4502 396 : recurse_push_qual(Node *setOp, Query *topquery,
4503 : RangeTblEntry *rte, Index rti, Node *qual)
4504 : {
4505 396 : if (IsA(setOp, RangeTblRef))
4506 : {
4507 264 : RangeTblRef *rtr = (RangeTblRef *) setOp;
4508 264 : RangeTblEntry *subrte = rt_fetch(rtr->rtindex, topquery->rtable);
4509 264 : Query *subquery = subrte->subquery;
4510 :
4511 : Assert(subquery != NULL);
4512 264 : subquery_push_qual(subquery, rte, rti, qual);
4513 : }
4514 132 : else if (IsA(setOp, SetOperationStmt))
4515 : {
4516 132 : SetOperationStmt *op = (SetOperationStmt *) setOp;
4517 :
4518 132 : recurse_push_qual(op->larg, topquery, rte, rti, qual);
4519 132 : recurse_push_qual(op->rarg, topquery, rte, rti, qual);
4520 : }
4521 : else
4522 : {
4523 0 : elog(ERROR, "unrecognized node type: %d",
4524 : (int) nodeTag(setOp));
4525 : }
4526 396 : }
4527 :
4528 : /*****************************************************************************
4529 : * SIMPLIFYING SUBQUERY TARGETLISTS
4530 : *****************************************************************************/
4531 :
4532 : /*
4533 : * remove_unused_subquery_outputs
4534 : * Remove subquery targetlist items we don't need
4535 : *
4536 : * It's possible, even likely, that the upper query does not read all the
4537 : * output columns of the subquery. We can remove any such outputs that are
4538 : * not needed by the subquery itself (e.g., as sort/group columns) and do not
4539 : * affect semantics otherwise (e.g., volatile functions can't be removed).
4540 : * This is useful not only because we might be able to remove expensive-to-
4541 : * compute expressions, but because deletion of output columns might allow
4542 : * optimizations such as join removal to occur within the subquery.
4543 : *
4544 : * extra_used_attrs can be passed as non-NULL to mark any columns (offset by
4545 : * FirstLowInvalidHeapAttributeNumber) that we should not remove. This
4546 : * parameter is modified by the function, so callers must make a copy if they
4547 : * need to use the passed in Bitmapset after calling this function.
4548 : *
4549 : * To avoid affecting column numbering in the targetlist, we don't physically
4550 : * remove unused tlist entries, but rather replace their expressions with NULL
4551 : * constants. This is implemented by modifying subquery->targetList.
4552 : */
4553 : static void
4554 17532 : remove_unused_subquery_outputs(Query *subquery, RelOptInfo *rel,
4555 : Bitmapset *extra_used_attrs)
4556 : {
4557 : Bitmapset *attrs_used;
4558 : ListCell *lc;
4559 :
4560 : /*
4561 : * Just point directly to extra_used_attrs. No need to bms_copy as none of
4562 : * the current callers use the Bitmapset after calling this function.
4563 : */
4564 17532 : attrs_used = extra_used_attrs;
4565 :
4566 : /*
4567 : * Do nothing if subquery has UNION/INTERSECT/EXCEPT: in principle we
4568 : * could update all the child SELECTs' tlists, but it seems not worth the
4569 : * trouble presently.
4570 : */
4571 17532 : if (subquery->setOperations)
4572 2008 : return;
4573 :
4574 : /*
4575 : * If subquery has regular DISTINCT (not DISTINCT ON), we're wasting our
4576 : * time: all its output columns must be used in the distinctClause.
4577 : */
4578 16698 : if (subquery->distinctClause && !subquery->hasDistinctOn)
4579 870 : return;
4580 :
4581 : /*
4582 : * Collect a bitmap of all the output column numbers used by the upper
4583 : * query.
4584 : *
4585 : * Add all the attributes needed for joins or final output. Note: we must
4586 : * look at rel's targetlist, not the attr_needed data, because attr_needed
4587 : * isn't computed for inheritance child rels, cf set_append_rel_size().
4588 : * (XXX might be worth changing that sometime.)
4589 : */
4590 15828 : pull_varattnos((Node *) rel->reltarget->exprs, rel->relid, &attrs_used);
4591 :
4592 : /* Add all the attributes used by un-pushed-down restriction clauses. */
4593 16564 : foreach(lc, rel->baserestrictinfo)
4594 : {
4595 736 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
4596 :
4597 736 : pull_varattnos((Node *) rinfo->clause, rel->relid, &attrs_used);
4598 : }
4599 :
4600 : /*
4601 : * If there's a whole-row reference to the subquery, we can't remove
4602 : * anything.
4603 : */
4604 15828 : if (bms_is_member(0 - FirstLowInvalidHeapAttributeNumber, attrs_used))
4605 304 : return;
4606 :
4607 : /*
4608 : * Run through the tlist and zap entries we don't need. It's okay to
4609 : * modify the tlist items in-place because set_subquery_pathlist made a
4610 : * copy of the subquery.
4611 : */
4612 91062 : foreach(lc, subquery->targetList)
4613 : {
4614 75538 : TargetEntry *tle = (TargetEntry *) lfirst(lc);
4615 75538 : Node *texpr = (Node *) tle->expr;
4616 :
4617 : /*
4618 : * If it has a sortgroupref number, it's used in some sort/group
4619 : * clause so we'd better not remove it. Also, don't remove any
4620 : * resjunk columns, since their reason for being has nothing to do
4621 : * with anybody reading the subquery's output. (It's likely that
4622 : * resjunk columns in a sub-SELECT would always have ressortgroupref
4623 : * set, but even if they don't, it seems imprudent to remove them.)
4624 : */
4625 75538 : if (tle->ressortgroupref || tle->resjunk)
4626 2928 : continue;
4627 :
4628 : /*
4629 : * If it's used by the upper query, we can't remove it.
4630 : */
4631 72610 : if (bms_is_member(tle->resno - FirstLowInvalidHeapAttributeNumber,
4632 : attrs_used))
4633 47408 : continue;
4634 :
4635 : /*
4636 : * If it contains a set-returning function, we can't remove it since
4637 : * that could change the number of rows returned by the subquery.
4638 : */
4639 26258 : if (subquery->hasTargetSRFs &&
4640 1056 : expression_returns_set(texpr))
4641 788 : continue;
4642 :
4643 : /*
4644 : * If it contains volatile functions, we daren't remove it for fear
4645 : * that the user is expecting their side-effects to happen.
4646 : */
4647 24414 : if (contain_volatile_functions(texpr))
4648 32 : continue;
4649 :
4650 : /*
4651 : * OK, we don't need it. Replace the expression with a NULL constant.
4652 : * Preserve the exposed type of the expression, in case something
4653 : * looks at the rowtype of the subquery's result.
4654 : */
4655 24382 : tle->expr = (Expr *) makeNullConst(exprType(texpr),
4656 : exprTypmod(texpr),
4657 : exprCollation(texpr));
4658 : }
4659 : }
4660 :
4661 : /*
4662 : * create_partial_bitmap_paths
4663 : * Build partial bitmap heap path for the relation
4664 : */
4665 : void
4666 144224 : create_partial_bitmap_paths(PlannerInfo *root, RelOptInfo *rel,
4667 : Path *bitmapqual)
4668 : {
4669 : int parallel_workers;
4670 : double pages_fetched;
4671 :
4672 : /* Compute heap pages for bitmap heap scan */
4673 144224 : pages_fetched = compute_bitmap_pages(root, rel, bitmapqual, 1.0,
4674 : NULL, NULL);
4675 :
4676 144224 : parallel_workers = compute_parallel_worker(rel, pages_fetched, -1,
4677 : max_parallel_workers_per_gather);
4678 :
4679 144224 : if (parallel_workers <= 0)
4680 140052 : return;
4681 :
4682 4172 : add_partial_path(rel, (Path *) create_bitmap_heap_path(root, rel,
4683 : bitmapqual, rel->lateral_relids, 1.0, parallel_workers));
4684 : }
4685 :
4686 : /*
4687 : * Compute the number of parallel workers that should be used to scan a
4688 : * relation. We compute the parallel workers based on the size of the heap to
4689 : * be scanned and the size of the index to be scanned, then choose a minimum
4690 : * of those.
4691 : *
4692 : * "heap_pages" is the number of pages from the table that we expect to scan, or
4693 : * -1 if we don't expect to scan any.
4694 : *
4695 : * "index_pages" is the number of pages from the index that we expect to scan, or
4696 : * -1 if we don't expect to scan any.
4697 : *
4698 : * "max_workers" is caller's limit on the number of workers. This typically
4699 : * comes from a GUC.
4700 : */
4701 : int
4702 758386 : compute_parallel_worker(RelOptInfo *rel, double heap_pages, double index_pages,
4703 : int max_workers)
4704 : {
4705 758386 : int parallel_workers = 0;
4706 :
4707 : /*
4708 : * If the user has set the parallel_workers reloption, use that; otherwise
4709 : * select a default number of workers.
4710 : */
4711 758386 : if (rel->rel_parallel_workers != -1)
4712 1914 : parallel_workers = rel->rel_parallel_workers;
4713 : else
4714 : {
4715 : /*
4716 : * If the number of pages being scanned is insufficient to justify a
4717 : * parallel scan, just return zero ... unless it's an inheritance
4718 : * child. In that case, we want to generate a parallel path here
4719 : * anyway. It might not be worthwhile just for this relation, but
4720 : * when combined with all of its inheritance siblings it may well pay
4721 : * off.
4722 : */
4723 756472 : if (rel->reloptkind == RELOPT_BASEREL &&
4724 717004 : ((heap_pages >= 0 && heap_pages < min_parallel_table_scan_size) ||
4725 24002 : (index_pages >= 0 && index_pages < min_parallel_index_scan_size)))
4726 716088 : return 0;
4727 :
4728 40384 : if (heap_pages >= 0)
4729 : {
4730 : int heap_parallel_threshold;
4731 38258 : int heap_parallel_workers = 1;
4732 :
4733 : /*
4734 : * Select the number of workers based on the log of the size of
4735 : * the relation. This probably needs to be a good deal more
4736 : * sophisticated, but we need something here for now. Note that
4737 : * the upper limit of the min_parallel_table_scan_size GUC is
4738 : * chosen to prevent overflow here.
4739 : */
4740 38258 : heap_parallel_threshold = Max(min_parallel_table_scan_size, 1);
4741 43498 : while (heap_pages >= (BlockNumber) (heap_parallel_threshold * 3))
4742 : {
4743 5240 : heap_parallel_workers++;
4744 5240 : heap_parallel_threshold *= 3;
4745 5240 : if (heap_parallel_threshold > INT_MAX / 3)
4746 0 : break; /* avoid overflow */
4747 : }
4748 :
4749 38258 : parallel_workers = heap_parallel_workers;
4750 : }
4751 :
4752 40384 : if (index_pages >= 0)
4753 : {
4754 9808 : int index_parallel_workers = 1;
4755 : int index_parallel_threshold;
4756 :
4757 : /* same calculation as for heap_pages above */
4758 9808 : index_parallel_threshold = Max(min_parallel_index_scan_size, 1);
4759 10084 : while (index_pages >= (BlockNumber) (index_parallel_threshold * 3))
4760 : {
4761 276 : index_parallel_workers++;
4762 276 : index_parallel_threshold *= 3;
4763 276 : if (index_parallel_threshold > INT_MAX / 3)
4764 0 : break; /* avoid overflow */
4765 : }
4766 :
4767 9808 : if (parallel_workers > 0)
4768 7682 : parallel_workers = Min(parallel_workers, index_parallel_workers);
4769 : else
4770 2126 : parallel_workers = index_parallel_workers;
4771 : }
4772 : }
4773 :
4774 : /* In no case use more than caller supplied maximum number of workers */
4775 42298 : parallel_workers = Min(parallel_workers, max_workers);
4776 :
4777 42298 : return parallel_workers;
4778 : }
4779 :
4780 : /*
4781 : * generate_partitionwise_join_paths
4782 : * Create paths representing partitionwise join for given partitioned
4783 : * join relation.
4784 : *
4785 : * This must not be called until after we are done adding paths for all
4786 : * child-joins. Otherwise, add_path might delete a path to which some path
4787 : * generated here has a reference.
4788 : */
4789 : void
4790 237002 : generate_partitionwise_join_paths(PlannerInfo *root, RelOptInfo *rel)
4791 : {
4792 237002 : List *live_children = NIL;
4793 : int cnt_parts;
4794 : int num_parts;
4795 : RelOptInfo **part_rels;
4796 :
4797 : /* Handle only join relations here. */
4798 237002 : if (!IS_JOIN_REL(rel))
4799 0 : return;
4800 :
4801 : /* We've nothing to do if the relation is not partitioned. */
4802 237002 : if (!IS_PARTITIONED_REL(rel))
4803 229856 : return;
4804 :
4805 : /* The relation should have consider_partitionwise_join set. */
4806 : Assert(rel->consider_partitionwise_join);
4807 :
4808 : /* Guard against stack overflow due to overly deep partition hierarchy. */
4809 7146 : check_stack_depth();
4810 :
4811 7146 : num_parts = rel->nparts;
4812 7146 : part_rels = rel->part_rels;
4813 :
4814 : /* Collect non-dummy child-joins. */
4815 25448 : for (cnt_parts = 0; cnt_parts < num_parts; cnt_parts++)
4816 : {
4817 18302 : RelOptInfo *child_rel = part_rels[cnt_parts];
4818 :
4819 : /* If it's been pruned entirely, it's certainly dummy. */
4820 18302 : if (child_rel == NULL)
4821 64 : continue;
4822 :
4823 : /* Make partitionwise join paths for this partitioned child-join. */
4824 18238 : generate_partitionwise_join_paths(root, child_rel);
4825 :
4826 : /* If we failed to make any path for this child, we must give up. */
4827 18238 : if (child_rel->pathlist == NIL)
4828 : {
4829 : /*
4830 : * Mark the parent joinrel as unpartitioned so that later
4831 : * functions treat it correctly.
4832 : */
4833 0 : rel->nparts = 0;
4834 0 : return;
4835 : }
4836 :
4837 : /* Else, identify the cheapest path for it. */
4838 18238 : set_cheapest(child_rel);
4839 :
4840 : /* Dummy children need not be scanned, so ignore those. */
4841 18238 : if (IS_DUMMY_REL(child_rel))
4842 0 : continue;
4843 :
4844 : /*
4845 : * Except for the topmost scan/join rel, consider generating partial
4846 : * aggregation paths for the grouped relation on top of the paths of
4847 : * this partitioned child-join. After that, we're done creating paths
4848 : * for the grouped relation, so run set_cheapest().
4849 : */
4850 18238 : if (child_rel->grouped_rel != NULL &&
4851 12876 : !bms_equal(IS_OTHER_REL(rel) ?
4852 : rel->top_parent_relids : rel->relids,
4853 12876 : root->all_query_rels))
4854 : {
4855 240 : RelOptInfo *grouped_rel = child_rel->grouped_rel;
4856 :
4857 : Assert(IS_GROUPED_REL(grouped_rel));
4858 :
4859 240 : generate_grouped_paths(root, grouped_rel, child_rel);
4860 240 : set_cheapest(grouped_rel);
4861 : }
4862 :
4863 : #ifdef OPTIMIZER_DEBUG
4864 : pprint(child_rel);
4865 : #endif
4866 :
4867 18238 : live_children = lappend(live_children, child_rel);
4868 : }
4869 :
4870 : /* If all child-joins are dummy, parent join is also dummy. */
4871 7146 : if (!live_children)
4872 : {
4873 0 : mark_dummy_rel(rel);
4874 0 : return;
4875 : }
4876 :
4877 : /* Build additional paths for this rel from child-join paths. */
4878 7146 : add_paths_to_append_rel(root, rel, live_children);
4879 7146 : list_free(live_children);
4880 : }
|
