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allpaths.c
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1 /*-------------------------------------------------------------------------
2  *
3  * allpaths.c
4  * Routines to find possible search paths for processing a query
5  *
6  * Portions Copyright (c) 1996-2021, 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 #ifdef OPTIMIZER_DEBUG
31 #include "nodes/print.h"
32 #endif
33 #include "optimizer/appendinfo.h"
34 #include "optimizer/clauses.h"
35 #include "optimizer/cost.h"
36 #include "optimizer/geqo.h"
37 #include "optimizer/inherit.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/restrictinfo.h"
44 #include "optimizer/tlist.h"
45 #include "parser/parse_clause.h"
46 #include "parser/parsetree.h"
48 #include "partitioning/partprune.h"
49 #include "rewrite/rewriteManip.h"
50 #include "utils/lsyscache.h"
51 
52 
53 /* results of subquery_is_pushdown_safe */
54 typedef struct pushdown_safety_info
55 {
56  bool *unsafeColumns; /* which output columns are unsafe to use */
57  bool unsafeVolatile; /* don't push down volatile quals */
58  bool unsafeLeaky; /* don't push down leaky quals */
60 
61 /* These parameters are set by GUC */
62 bool enable_geqo = false; /* just in case GUC doesn't set it */
66 
67 /* Hook for plugins to get control in set_rel_pathlist() */
69 
70 /* Hook for plugins to replace standard_join_search() */
72 
73 
75 static void set_base_rel_sizes(PlannerInfo *root);
76 static void set_base_rel_pathlists(PlannerInfo *root);
77 static void set_rel_size(PlannerInfo *root, RelOptInfo *rel,
78  Index rti, RangeTblEntry *rte);
79 static void set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
80  Index rti, RangeTblEntry *rte);
81 static void set_plain_rel_size(PlannerInfo *root, RelOptInfo *rel,
82  RangeTblEntry *rte);
83 static void create_plain_partial_paths(PlannerInfo *root, RelOptInfo *rel);
84 static void set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
85  RangeTblEntry *rte);
86 static void set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
87  RangeTblEntry *rte);
88 static void set_tablesample_rel_size(PlannerInfo *root, RelOptInfo *rel,
89  RangeTblEntry *rte);
91  RangeTblEntry *rte);
92 static void set_foreign_size(PlannerInfo *root, RelOptInfo *rel,
93  RangeTblEntry *rte);
94 static void set_foreign_pathlist(PlannerInfo *root, RelOptInfo *rel,
95  RangeTblEntry *rte);
96 static void set_append_rel_size(PlannerInfo *root, RelOptInfo *rel,
97  Index rti, RangeTblEntry *rte);
98 static void set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
99  Index rti, RangeTblEntry *rte);
100 static void generate_orderedappend_paths(PlannerInfo *root, RelOptInfo *rel,
101  List *live_childrels,
102  List *all_child_pathkeys);
104  RelOptInfo *rel,
105  Relids required_outer);
106 static void accumulate_append_subpath(Path *path,
107  List **subpaths,
108  List **special_subpaths);
109 static Path *get_singleton_append_subpath(Path *path);
110 static void set_dummy_rel_pathlist(RelOptInfo *rel);
111 static void set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
112  Index rti, RangeTblEntry *rte);
113 static void set_function_pathlist(PlannerInfo *root, RelOptInfo *rel,
114  RangeTblEntry *rte);
115 static void set_values_pathlist(PlannerInfo *root, RelOptInfo *rel,
116  RangeTblEntry *rte);
117 static void set_tablefunc_pathlist(PlannerInfo *root, RelOptInfo *rel,
118  RangeTblEntry *rte);
119 static void set_cte_pathlist(PlannerInfo *root, RelOptInfo *rel,
120  RangeTblEntry *rte);
121 static void set_namedtuplestore_pathlist(PlannerInfo *root, RelOptInfo *rel,
122  RangeTblEntry *rte);
123 static void set_result_pathlist(PlannerInfo *root, RelOptInfo *rel,
124  RangeTblEntry *rte);
125 static void set_worktable_pathlist(PlannerInfo *root, RelOptInfo *rel,
126  RangeTblEntry *rte);
127 static RelOptInfo *make_rel_from_joinlist(PlannerInfo *root, List *joinlist);
128 static bool subquery_is_pushdown_safe(Query *subquery, Query *topquery,
129  pushdown_safety_info *safetyInfo);
130 static bool recurse_pushdown_safe(Node *setOp, Query *topquery,
131  pushdown_safety_info *safetyInfo);
132 static void check_output_expressions(Query *subquery,
133  pushdown_safety_info *safetyInfo);
134 static void compare_tlist_datatypes(List *tlist, List *colTypes,
135  pushdown_safety_info *safetyInfo);
136 static bool targetIsInAllPartitionLists(TargetEntry *tle, Query *query);
137 static bool qual_is_pushdown_safe(Query *subquery, Index rti,
138  RestrictInfo *rinfo,
139  pushdown_safety_info *safetyInfo);
140 static void subquery_push_qual(Query *subquery,
141  RangeTblEntry *rte, Index rti, Node *qual);
142 static void recurse_push_qual(Node *setOp, Query *topquery,
143  RangeTblEntry *rte, Index rti, Node *qual);
144 static void remove_unused_subquery_outputs(Query *subquery, RelOptInfo *rel);
145 
146 
147 /*
148  * make_one_rel
149  * Finds all possible access paths for executing a query, returning a
150  * single rel that represents the join of all base rels in the query.
151  */
152 RelOptInfo *
153 make_one_rel(PlannerInfo *root, List *joinlist)
154 {
155  RelOptInfo *rel;
156  Index rti;
157  double total_pages;
158 
159  /*
160  * Construct the all_baserels Relids set.
161  */
162  root->all_baserels = NULL;
163  for (rti = 1; rti < root->simple_rel_array_size; rti++)
164  {
165  RelOptInfo *brel = root->simple_rel_array[rti];
166 
167  /* there may be empty slots corresponding to non-baserel RTEs */
168  if (brel == NULL)
169  continue;
170 
171  Assert(brel->relid == rti); /* sanity check on array */
172 
173  /* ignore RTEs that are "other rels" */
174  if (brel->reloptkind != RELOPT_BASEREL)
175  continue;
176 
177  root->all_baserels = bms_add_member(root->all_baserels, brel->relid);
178  }
179 
180  /* Mark base rels as to whether we care about fast-start plans */
182 
183  /*
184  * Compute size estimates and consider_parallel flags for each base rel.
185  */
186  set_base_rel_sizes(root);
187 
188  /*
189  * We should now have size estimates for every actual table involved in
190  * the query, and we also know which if any have been deleted from the
191  * query by join removal, pruned by partition pruning, or eliminated by
192  * constraint exclusion. So we can now compute total_table_pages.
193  *
194  * Note that appendrels are not double-counted here, even though we don't
195  * bother to distinguish RelOptInfos for appendrel parents, because the
196  * parents will have pages = 0.
197  *
198  * XXX if a table is self-joined, we will count it once per appearance,
199  * which perhaps is the wrong thing ... but that's not completely clear,
200  * and detecting self-joins here is difficult, so ignore it for now.
201  */
202  total_pages = 0;
203  for (rti = 1; rti < root->simple_rel_array_size; rti++)
204  {
205  RelOptInfo *brel = root->simple_rel_array[rti];
206 
207  if (brel == NULL)
208  continue;
209 
210  Assert(brel->relid == rti); /* sanity check on array */
211 
212  if (IS_DUMMY_REL(brel))
213  continue;
214 
215  if (IS_SIMPLE_REL(brel))
216  total_pages += (double) brel->pages;
217  }
218  root->total_table_pages = total_pages;
219 
220  /*
221  * Generate access paths for each base rel.
222  */
224 
225  /*
226  * Generate access paths for the entire join tree.
227  */
228  rel = make_rel_from_joinlist(root, joinlist);
229 
230  /*
231  * The result should join all and only the query's base rels.
232  */
233  Assert(bms_equal(rel->relids, root->all_baserels));
234 
235  return rel;
236 }
237 
238 /*
239  * set_base_rel_consider_startup
240  * Set the consider_[param_]startup flags for each base-relation entry.
241  *
242  * For the moment, we only deal with consider_param_startup here; because the
243  * logic for consider_startup is pretty trivial and is the same for every base
244  * relation, we just let build_simple_rel() initialize that flag correctly to
245  * start with. If that logic ever gets more complicated it would probably
246  * be better to move it here.
247  */
248 static void
250 {
251  /*
252  * Since parameterized paths can only be used on the inside of a nestloop
253  * join plan, there is usually little value in considering fast-start
254  * plans for them. However, for relations that are on the RHS of a SEMI
255  * or ANTI join, a fast-start plan can be useful because we're only going
256  * to care about fetching one tuple anyway.
257  *
258  * To minimize growth of planning time, we currently restrict this to
259  * cases where the RHS is a single base relation, not a join; there is no
260  * provision for consider_param_startup to get set at all on joinrels.
261  * Also we don't worry about appendrels. costsize.c's costing rules for
262  * nestloop semi/antijoins don't consider such cases either.
263  */
264  ListCell *lc;
265 
266  foreach(lc, root->join_info_list)
267  {
268  SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(lc);
269  int varno;
270 
271  if ((sjinfo->jointype == JOIN_SEMI || sjinfo->jointype == JOIN_ANTI) &&
272  bms_get_singleton_member(sjinfo->syn_righthand, &varno))
273  {
274  RelOptInfo *rel = find_base_rel(root, varno);
275 
276  rel->consider_param_startup = true;
277  }
278  }
279 }
280 
281 /*
282  * set_base_rel_sizes
283  * Set the size estimates (rows and widths) for each base-relation entry.
284  * Also determine whether to consider parallel paths for base relations.
285  *
286  * We do this in a separate pass over the base rels so that rowcount
287  * estimates are available for parameterized path generation, and also so
288  * that each rel's consider_parallel flag is set correctly before we begin to
289  * generate paths.
290  */
291 static void
293 {
294  Index rti;
295 
296  for (rti = 1; rti < root->simple_rel_array_size; rti++)
297  {
298  RelOptInfo *rel = root->simple_rel_array[rti];
299  RangeTblEntry *rte;
300 
301  /* there may be empty slots corresponding to non-baserel RTEs */
302  if (rel == NULL)
303  continue;
304 
305  Assert(rel->relid == rti); /* sanity check on array */
306 
307  /* ignore RTEs that are "other rels" */
308  if (rel->reloptkind != RELOPT_BASEREL)
309  continue;
310 
311  rte = root->simple_rte_array[rti];
312 
313  /*
314  * If parallelism is allowable for this query in general, see whether
315  * it's allowable for this rel in particular. We have to do this
316  * before set_rel_size(), because (a) if this rel is an inheritance
317  * parent, set_append_rel_size() will use and perhaps change the rel's
318  * consider_parallel flag, and (b) for some RTE types, set_rel_size()
319  * goes ahead and makes paths immediately.
320  */
321  if (root->glob->parallelModeOK)
322  set_rel_consider_parallel(root, rel, rte);
323 
324  set_rel_size(root, rel, rti, rte);
325  }
326 }
327 
328 /*
329  * set_base_rel_pathlists
330  * Finds all paths available for scanning each base-relation entry.
331  * Sequential scan and any available indices are considered.
332  * Each useful path is attached to its relation's 'pathlist' field.
333  */
334 static void
336 {
337  Index rti;
338 
339  for (rti = 1; rti < root->simple_rel_array_size; rti++)
340  {
341  RelOptInfo *rel = root->simple_rel_array[rti];
342 
343  /* there may be empty slots corresponding to non-baserel RTEs */
344  if (rel == NULL)
345  continue;
346 
347  Assert(rel->relid == rti); /* sanity check on array */
348 
349  /* ignore RTEs that are "other rels" */
350  if (rel->reloptkind != RELOPT_BASEREL)
351  continue;
352 
353  set_rel_pathlist(root, rel, rti, root->simple_rte_array[rti]);
354  }
355 }
356 
357 /*
358  * set_rel_size
359  * Set size estimates for a base relation
360  */
361 static void
363  Index rti, RangeTblEntry *rte)
364 {
365  if (rel->reloptkind == RELOPT_BASEREL &&
366  relation_excluded_by_constraints(root, rel, rte))
367  {
368  /*
369  * We proved we don't need to scan the rel via constraint exclusion,
370  * so set up a single dummy path for it. Here we only check this for
371  * regular baserels; if it's an otherrel, CE was already checked in
372  * set_append_rel_size().
373  *
374  * In this case, we go ahead and set up the relation's path right away
375  * instead of leaving it for set_rel_pathlist to do. This is because
376  * we don't have a convention for marking a rel as dummy except by
377  * assigning a dummy path to it.
378  */
380  }
381  else if (rte->inh)
382  {
383  /* It's an "append relation", process accordingly */
384  set_append_rel_size(root, rel, rti, rte);
385  }
386  else
387  {
388  switch (rel->rtekind)
389  {
390  case RTE_RELATION:
391  if (rte->relkind == RELKIND_FOREIGN_TABLE)
392  {
393  /* Foreign table */
394  set_foreign_size(root, rel, rte);
395  }
396  else if (rte->relkind == RELKIND_PARTITIONED_TABLE)
397  {
398  /*
399  * We could get here if asked to scan a partitioned table
400  * with ONLY. In that case we shouldn't scan any of the
401  * partitions, so mark it as a dummy rel.
402  */
404  }
405  else if (rte->tablesample != NULL)
406  {
407  /* Sampled relation */
408  set_tablesample_rel_size(root, rel, rte);
409  }
410  else
411  {
412  /* Plain relation */
413  set_plain_rel_size(root, rel, rte);
414  }
415  break;
416  case RTE_SUBQUERY:
417 
418  /*
419  * Subqueries don't support making a choice between
420  * parameterized and unparameterized paths, so just go ahead
421  * and build their paths immediately.
422  */
423  set_subquery_pathlist(root, rel, rti, rte);
424  break;
425  case RTE_FUNCTION:
426  set_function_size_estimates(root, rel);
427  break;
428  case RTE_TABLEFUNC:
429  set_tablefunc_size_estimates(root, rel);
430  break;
431  case RTE_VALUES:
432  set_values_size_estimates(root, rel);
433  break;
434  case RTE_CTE:
435 
436  /*
437  * CTEs don't support making a choice between parameterized
438  * and unparameterized paths, so just go ahead and build their
439  * paths immediately.
440  */
441  if (rte->self_reference)
442  set_worktable_pathlist(root, rel, rte);
443  else
444  set_cte_pathlist(root, rel, rte);
445  break;
446  case RTE_NAMEDTUPLESTORE:
447  /* Might as well just build the path immediately */
448  set_namedtuplestore_pathlist(root, rel, rte);
449  break;
450  case RTE_RESULT:
451  /* Might as well just build the path immediately */
452  set_result_pathlist(root, rel, rte);
453  break;
454  default:
455  elog(ERROR, "unexpected rtekind: %d", (int) rel->rtekind);
456  break;
457  }
458  }
459 
460  /*
461  * We insist that all non-dummy rels have a nonzero rowcount estimate.
462  */
463  Assert(rel->rows > 0 || IS_DUMMY_REL(rel));
464 }
465 
466 /*
467  * set_rel_pathlist
468  * Build access paths for a base relation
469  */
470 static void
472  Index rti, RangeTblEntry *rte)
473 {
474  if (IS_DUMMY_REL(rel))
475  {
476  /* We already proved the relation empty, so nothing more to do */
477  }
478  else if (rte->inh)
479  {
480  /* It's an "append relation", process accordingly */
481  set_append_rel_pathlist(root, rel, rti, rte);
482  }
483  else
484  {
485  switch (rel->rtekind)
486  {
487  case RTE_RELATION:
488  if (rte->relkind == RELKIND_FOREIGN_TABLE)
489  {
490  /* Foreign table */
491  set_foreign_pathlist(root, rel, rte);
492  }
493  else if (rte->tablesample != NULL)
494  {
495  /* Sampled relation */
496  set_tablesample_rel_pathlist(root, rel, rte);
497  }
498  else
499  {
500  /* Plain relation */
501  set_plain_rel_pathlist(root, rel, rte);
502  }
503  break;
504  case RTE_SUBQUERY:
505  /* Subquery --- fully handled during set_rel_size */
506  break;
507  case RTE_FUNCTION:
508  /* RangeFunction */
509  set_function_pathlist(root, rel, rte);
510  break;
511  case RTE_TABLEFUNC:
512  /* Table Function */
513  set_tablefunc_pathlist(root, rel, rte);
514  break;
515  case RTE_VALUES:
516  /* Values list */
517  set_values_pathlist(root, rel, rte);
518  break;
519  case RTE_CTE:
520  /* CTE reference --- fully handled during set_rel_size */
521  break;
522  case RTE_NAMEDTUPLESTORE:
523  /* tuplestore reference --- fully handled during set_rel_size */
524  break;
525  case RTE_RESULT:
526  /* simple Result --- fully handled during set_rel_size */
527  break;
528  default:
529  elog(ERROR, "unexpected rtekind: %d", (int) rel->rtekind);
530  break;
531  }
532  }
533 
534  /*
535  * Allow a plugin to editorialize on the set of Paths for this base
536  * relation. It could add new paths (such as CustomPaths) by calling
537  * add_path(), or add_partial_path() if parallel aware. It could also
538  * delete or modify paths added by the core code.
539  */
541  (*set_rel_pathlist_hook) (root, rel, rti, rte);
542 
543  /*
544  * If this is a baserel, we should normally consider gathering any partial
545  * paths we may have created for it. We have to do this after calling the
546  * set_rel_pathlist_hook, else it cannot add partial paths to be included
547  * here.
548  *
549  * However, if this is an inheritance child, skip it. Otherwise, we could
550  * end up with a very large number of gather nodes, each trying to grab
551  * its own pool of workers. Instead, we'll consider gathering partial
552  * paths for the parent appendrel.
553  *
554  * Also, if this is the topmost scan/join rel (that is, the only baserel),
555  * we postpone gathering until the final scan/join targetlist is available
556  * (see grouping_planner).
557  */
558  if (rel->reloptkind == RELOPT_BASEREL &&
559  bms_membership(root->all_baserels) != BMS_SINGLETON)
560  generate_useful_gather_paths(root, rel, false);
561 
562  /* Now find the cheapest of the paths for this rel */
563  set_cheapest(rel);
564 
565 #ifdef OPTIMIZER_DEBUG
566  debug_print_rel(root, rel);
567 #endif
568 }
569 
570 /*
571  * set_plain_rel_size
572  * Set size estimates for a plain relation (no subquery, no inheritance)
573  */
574 static void
576 {
577  /*
578  * Test any partial indexes of rel for applicability. We must do this
579  * first since partial unique indexes can affect size estimates.
580  */
581  check_index_predicates(root, rel);
582 
583  /* Mark rel with estimated output rows, width, etc */
584  set_baserel_size_estimates(root, rel);
585 }
586 
587 /*
588  * If this relation could possibly be scanned from within a worker, then set
589  * its consider_parallel flag.
590  */
591 static void
593  RangeTblEntry *rte)
594 {
595  /*
596  * The flag has previously been initialized to false, so we can just
597  * return if it becomes clear that we can't safely set it.
598  */
599  Assert(!rel->consider_parallel);
600 
601  /* Don't call this if parallelism is disallowed for the entire query. */
602  Assert(root->glob->parallelModeOK);
603 
604  /* This should only be called for baserels and appendrel children. */
605  Assert(IS_SIMPLE_REL(rel));
606 
607  /* Assorted checks based on rtekind. */
608  switch (rte->rtekind)
609  {
610  case RTE_RELATION:
611 
612  /*
613  * Currently, parallel workers can't access the leader's temporary
614  * tables. We could possibly relax this if we wrote all of its
615  * local buffers at the start of the query and made no changes
616  * thereafter (maybe we could allow hint bit changes), and if we
617  * taught the workers to read them. Writing a large number of
618  * temporary buffers could be expensive, though, and we don't have
619  * the rest of the necessary infrastructure right now anyway. So
620  * for now, bail out if we see a temporary table.
621  */
622  if (get_rel_persistence(rte->relid) == RELPERSISTENCE_TEMP)
623  return;
624 
625  /*
626  * Table sampling can be pushed down to workers if the sample
627  * function and its arguments are safe.
628  */
629  if (rte->tablesample != NULL)
630  {
631  char proparallel = func_parallel(rte->tablesample->tsmhandler);
632 
633  if (proparallel != PROPARALLEL_SAFE)
634  return;
635  if (!is_parallel_safe(root, (Node *) rte->tablesample->args))
636  return;
637  }
638 
639  /*
640  * Ask FDWs whether they can support performing a ForeignScan
641  * within a worker. Most often, the answer will be no. For
642  * example, if the nature of the FDW is such that it opens a TCP
643  * connection with a remote server, each parallel worker would end
644  * up with a separate connection, and these connections might not
645  * be appropriately coordinated between workers and the leader.
646  */
647  if (rte->relkind == RELKIND_FOREIGN_TABLE)
648  {
649  Assert(rel->fdwroutine);
651  return;
652  if (!rel->fdwroutine->IsForeignScanParallelSafe(root, rel, rte))
653  return;
654  }
655 
656  /*
657  * There are additional considerations for appendrels, which we'll
658  * deal with in set_append_rel_size and set_append_rel_pathlist.
659  * For now, just set consider_parallel based on the rel's own
660  * quals and targetlist.
661  */
662  break;
663 
664  case RTE_SUBQUERY:
665 
666  /*
667  * There's no intrinsic problem with scanning a subquery-in-FROM
668  * (as distinct from a SubPlan or InitPlan) in a parallel worker.
669  * If the subquery doesn't happen to have any parallel-safe paths,
670  * then flagging it as consider_parallel won't change anything,
671  * but that's true for plain tables, too. We must set
672  * consider_parallel based on the rel's own quals and targetlist,
673  * so that if a subquery path is parallel-safe but the quals and
674  * projection we're sticking onto it are not, we correctly mark
675  * the SubqueryScanPath as not parallel-safe. (Note that
676  * set_subquery_pathlist() might push some of these quals down
677  * into the subquery itself, but that doesn't change anything.)
678  *
679  * We can't push sub-select containing LIMIT/OFFSET to workers as
680  * there is no guarantee that the row order will be fully
681  * deterministic, and applying LIMIT/OFFSET will lead to
682  * inconsistent results at the top-level. (In some cases, where
683  * the result is ordered, we could relax this restriction. But it
684  * doesn't currently seem worth expending extra effort to do so.)
685  */
686  {
687  Query *subquery = castNode(Query, rte->subquery);
688 
689  if (limit_needed(subquery))
690  return;
691  }
692  break;
693 
694  case RTE_JOIN:
695  /* Shouldn't happen; we're only considering baserels here. */
696  Assert(false);
697  return;
698 
699  case RTE_FUNCTION:
700  /* Check for parallel-restricted functions. */
701  if (!is_parallel_safe(root, (Node *) rte->functions))
702  return;
703  break;
704 
705  case RTE_TABLEFUNC:
706  /* not parallel safe */
707  return;
708 
709  case RTE_VALUES:
710  /* Check for parallel-restricted functions. */
711  if (!is_parallel_safe(root, (Node *) rte->values_lists))
712  return;
713  break;
714 
715  case RTE_CTE:
716 
717  /*
718  * CTE tuplestores aren't shared among parallel workers, so we
719  * force all CTE scans to happen in the leader. Also, populating
720  * the CTE would require executing a subplan that's not available
721  * in the worker, might be parallel-restricted, and must get
722  * executed only once.
723  */
724  return;
725 
726  case RTE_NAMEDTUPLESTORE:
727 
728  /*
729  * tuplestore cannot be shared, at least without more
730  * infrastructure to support that.
731  */
732  return;
733 
734  case RTE_RESULT:
735  /* RESULT RTEs, in themselves, are no problem. */
736  break;
737  }
738 
739  /*
740  * If there's anything in baserestrictinfo that's parallel-restricted, we
741  * give up on parallelizing access to this relation. We could consider
742  * instead postponing application of the restricted quals until we're
743  * above all the parallelism in the plan tree, but it's not clear that
744  * that would be a win in very many cases, and it might be tricky to make
745  * outer join clauses work correctly. It would likely break equivalence
746  * classes, too.
747  */
748  if (!is_parallel_safe(root, (Node *) rel->baserestrictinfo))
749  return;
750 
751  /*
752  * Likewise, if the relation's outputs are not parallel-safe, give up.
753  * (Usually, they're just Vars, but sometimes they're not.)
754  */
755  if (!is_parallel_safe(root, (Node *) rel->reltarget->exprs))
756  return;
757 
758  /* We have a winner. */
759  rel->consider_parallel = true;
760 }
761 
762 /*
763  * set_plain_rel_pathlist
764  * Build access paths for a plain relation (no subquery, no inheritance)
765  */
766 static void
768 {
769  Relids required_outer;
770 
771  /*
772  * We don't support pushing join clauses into the quals of a seqscan, but
773  * it could still have required parameterization due to LATERAL refs in
774  * its tlist.
775  */
776  required_outer = rel->lateral_relids;
777 
778  /* Consider sequential scan */
779  add_path(rel, create_seqscan_path(root, rel, required_outer, 0));
780 
781  /* If appropriate, consider parallel sequential scan */
782  if (rel->consider_parallel && required_outer == NULL)
783  create_plain_partial_paths(root, rel);
784 
785  /* Consider index scans */
786  create_index_paths(root, rel);
787 
788  /* Consider TID scans */
789  create_tidscan_paths(root, rel);
790 }
791 
792 /*
793  * create_plain_partial_paths
794  * Build partial access paths for parallel scan of a plain relation
795  */
796 static void
798 {
799  int parallel_workers;
800 
801  parallel_workers = compute_parallel_worker(rel, rel->pages, -1,
803 
804  /* If any limit was set to zero, the user doesn't want a parallel scan. */
805  if (parallel_workers <= 0)
806  return;
807 
808  /* Add an unordered partial path based on a parallel sequential scan. */
809  add_partial_path(rel, create_seqscan_path(root, rel, NULL, parallel_workers));
810 }
811 
812 /*
813  * set_tablesample_rel_size
814  * Set size estimates for a sampled relation
815  */
816 static void
818 {
819  TableSampleClause *tsc = rte->tablesample;
820  TsmRoutine *tsm;
821  BlockNumber pages;
822  double tuples;
823 
824  /*
825  * Test any partial indexes of rel for applicability. We must do this
826  * first since partial unique indexes can affect size estimates.
827  */
828  check_index_predicates(root, rel);
829 
830  /*
831  * Call the sampling method's estimation function to estimate the number
832  * of pages it will read and the number of tuples it will return. (Note:
833  * we assume the function returns sane values.)
834  */
835  tsm = GetTsmRoutine(tsc->tsmhandler);
836  tsm->SampleScanGetSampleSize(root, rel, tsc->args,
837  &pages, &tuples);
838 
839  /*
840  * For the moment, because we will only consider a SampleScan path for the
841  * rel, it's okay to just overwrite the pages and tuples estimates for the
842  * whole relation. If we ever consider multiple path types for sampled
843  * rels, we'll need more complication.
844  */
845  rel->pages = pages;
846  rel->tuples = tuples;
847 
848  /* Mark rel with estimated output rows, width, etc */
849  set_baserel_size_estimates(root, rel);
850 }
851 
852 /*
853  * set_tablesample_rel_pathlist
854  * Build access paths for a sampled relation
855  */
856 static void
858 {
859  Relids required_outer;
860  Path *path;
861 
862  /*
863  * We don't support pushing join clauses into the quals of a samplescan,
864  * but it could still have required parameterization due to LATERAL refs
865  * in its tlist or TABLESAMPLE arguments.
866  */
867  required_outer = rel->lateral_relids;
868 
869  /* Consider sampled scan */
870  path = create_samplescan_path(root, rel, required_outer);
871 
872  /*
873  * If the sampling method does not support repeatable scans, we must avoid
874  * plans that would scan the rel multiple times. Ideally, we'd simply
875  * avoid putting the rel on the inside of a nestloop join; but adding such
876  * a consideration to the planner seems like a great deal of complication
877  * to support an uncommon usage of second-rate sampling methods. Instead,
878  * if there is a risk that the query might perform an unsafe join, just
879  * wrap the SampleScan in a Materialize node. We can check for joins by
880  * counting the membership of all_baserels (note that this correctly
881  * counts inheritance trees as single rels). If we're inside a subquery,
882  * we can't easily check whether a join might occur in the outer query, so
883  * just assume one is possible.
884  *
885  * GetTsmRoutine is relatively expensive compared to the other tests here,
886  * so check repeatable_across_scans last, even though that's a bit odd.
887  */
888  if ((root->query_level > 1 ||
891  {
892  path = (Path *) create_material_path(rel, path);
893  }
894 
895  add_path(rel, path);
896 
897  /* For the moment, at least, there are no other paths to consider */
898 }
899 
900 /*
901  * set_foreign_size
902  * Set size estimates for a foreign table RTE
903  */
904 static void
906 {
907  /* Mark rel with estimated output rows, width, etc */
908  set_foreign_size_estimates(root, rel);
909 
910  /* Let FDW adjust the size estimates, if it can */
911  rel->fdwroutine->GetForeignRelSize(root, rel, rte->relid);
912 
913  /* ... but do not let it set the rows estimate to zero */
914  rel->rows = clamp_row_est(rel->rows);
915 
916  /*
917  * Also, make sure rel->tuples is not insane relative to rel->rows.
918  * Notably, this ensures sanity if pg_class.reltuples contains -1 and the
919  * FDW doesn't do anything to replace that.
920  */
921  rel->tuples = Max(rel->tuples, rel->rows);
922 }
923 
924 /*
925  * set_foreign_pathlist
926  * Build access paths for a foreign table RTE
927  */
928 static void
930 {
931  /* Call the FDW's GetForeignPaths function to generate path(s) */
932  rel->fdwroutine->GetForeignPaths(root, rel, rte->relid);
933 }
934 
935 /*
936  * set_append_rel_size
937  * Set size estimates for a simple "append relation"
938  *
939  * The passed-in rel and RTE represent the entire append relation. The
940  * relation's contents are computed by appending together the output of the
941  * individual member relations. Note that in the non-partitioned inheritance
942  * case, the first member relation is actually the same table as is mentioned
943  * in the parent RTE ... but it has a different RTE and RelOptInfo. This is
944  * a good thing because their outputs are not the same size.
945  */
946 static void
948  Index rti, RangeTblEntry *rte)
949 {
950  int parentRTindex = rti;
951  bool has_live_children;
952  double parent_rows;
953  double parent_size;
954  double *parent_attrsizes;
955  int nattrs;
956  ListCell *l;
957 
958  /* Guard against stack overflow due to overly deep inheritance tree. */
960 
961  Assert(IS_SIMPLE_REL(rel));
962 
963  /*
964  * If this is a partitioned baserel, set the consider_partitionwise_join
965  * flag; currently, we only consider partitionwise joins with the baserel
966  * if its targetlist doesn't contain a whole-row Var.
967  */
969  rel->reloptkind == RELOPT_BASEREL &&
970  rte->relkind == RELKIND_PARTITIONED_TABLE &&
971  rel->attr_needed[InvalidAttrNumber - rel->min_attr] == NULL)
972  rel->consider_partitionwise_join = true;
973 
974  /*
975  * Initialize to compute size estimates for whole append relation.
976  *
977  * We handle width estimates by weighting the widths of different child
978  * rels proportionally to their number of rows. This is sensible because
979  * the use of width estimates is mainly to compute the total relation
980  * "footprint" if we have to sort or hash it. To do this, we sum the
981  * total equivalent size (in "double" arithmetic) and then divide by the
982  * total rowcount estimate. This is done separately for the total rel
983  * width and each attribute.
984  *
985  * Note: if you consider changing this logic, beware that child rels could
986  * have zero rows and/or width, if they were excluded by constraints.
987  */
988  has_live_children = false;
989  parent_rows = 0;
990  parent_size = 0;
991  nattrs = rel->max_attr - rel->min_attr + 1;
992  parent_attrsizes = (double *) palloc0(nattrs * sizeof(double));
993 
994  foreach(l, root->append_rel_list)
995  {
996  AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
997  int childRTindex;
998  RangeTblEntry *childRTE;
999  RelOptInfo *childrel;
1000  ListCell *parentvars;
1001  ListCell *childvars;
1002 
1003  /* append_rel_list contains all append rels; ignore others */
1004  if (appinfo->parent_relid != parentRTindex)
1005  continue;
1006 
1007  childRTindex = appinfo->child_relid;
1008  childRTE = root->simple_rte_array[childRTindex];
1009 
1010  /*
1011  * The child rel's RelOptInfo was already created during
1012  * add_other_rels_to_query.
1013  */
1014  childrel = find_base_rel(root, childRTindex);
1016 
1017  /* We may have already proven the child to be dummy. */
1018  if (IS_DUMMY_REL(childrel))
1019  continue;
1020 
1021  /*
1022  * We have to copy the parent's targetlist and quals to the child,
1023  * with appropriate substitution of variables. However, the
1024  * baserestrictinfo quals were already copied/substituted when the
1025  * child RelOptInfo was built. So we don't need any additional setup
1026  * before applying constraint exclusion.
1027  */
1028  if (relation_excluded_by_constraints(root, childrel, childRTE))
1029  {
1030  /*
1031  * This child need not be scanned, so we can omit it from the
1032  * appendrel.
1033  */
1034  set_dummy_rel_pathlist(childrel);
1035  continue;
1036  }
1037 
1038  /*
1039  * Constraint exclusion failed, so copy the parent's join quals and
1040  * targetlist to the child, with appropriate variable substitutions.
1041  *
1042  * NB: the resulting childrel->reltarget->exprs may contain arbitrary
1043  * expressions, which otherwise would not occur in a rel's targetlist.
1044  * Code that might be looking at an appendrel child must cope with
1045  * such. (Normally, a rel's targetlist would only include Vars and
1046  * PlaceHolderVars.) XXX we do not bother to update the cost or width
1047  * fields of childrel->reltarget; not clear if that would be useful.
1048  */
1049  childrel->joininfo = (List *)
1051  (Node *) rel->joininfo,
1052  1, &appinfo);
1053  childrel->reltarget->exprs = (List *)
1055  (Node *) rel->reltarget->exprs,
1056  1, &appinfo);
1057 
1058  /*
1059  * We have to make child entries in the EquivalenceClass data
1060  * structures as well. This is needed either if the parent
1061  * participates in some eclass joins (because we will want to consider
1062  * inner-indexscan joins on the individual children) or if the parent
1063  * has useful pathkeys (because we should try to build MergeAppend
1064  * paths that produce those sort orderings).
1065  */
1066  if (rel->has_eclass_joins || has_useful_pathkeys(root, rel))
1067  add_child_rel_equivalences(root, appinfo, rel, childrel);
1068  childrel->has_eclass_joins = rel->has_eclass_joins;
1069 
1070  /*
1071  * Note: we could compute appropriate attr_needed data for the child's
1072  * variables, by transforming the parent's attr_needed through the
1073  * translated_vars mapping. However, currently there's no need
1074  * because attr_needed is only examined for base relations not
1075  * otherrels. So we just leave the child's attr_needed empty.
1076  */
1077 
1078  /*
1079  * If we consider partitionwise joins with the parent rel, do the same
1080  * for partitioned child rels.
1081  *
1082  * Note: here we abuse the consider_partitionwise_join flag by setting
1083  * it for child rels that are not themselves partitioned. We do so to
1084  * tell try_partitionwise_join() that the child rel is sufficiently
1085  * valid to be used as a per-partition input, even if it later gets
1086  * proven to be dummy. (It's not usable until we've set up the
1087  * reltarget and EC entries, which we just did.)
1088  */
1089  if (rel->consider_partitionwise_join)
1090  childrel->consider_partitionwise_join = true;
1091 
1092  /*
1093  * If parallelism is allowable for this query in general, see whether
1094  * it's allowable for this childrel in particular. But if we've
1095  * already decided the appendrel is not parallel-safe as a whole,
1096  * there's no point in considering parallelism for this child. For
1097  * consistency, do this before calling set_rel_size() for the child.
1098  */
1099  if (root->glob->parallelModeOK && rel->consider_parallel)
1100  set_rel_consider_parallel(root, childrel, childRTE);
1101 
1102  /*
1103  * Compute the child's size.
1104  */
1105  set_rel_size(root, childrel, childRTindex, childRTE);
1106 
1107  /*
1108  * It is possible that constraint exclusion detected a contradiction
1109  * within a child subquery, even though we didn't prove one above. If
1110  * so, we can skip this child.
1111  */
1112  if (IS_DUMMY_REL(childrel))
1113  continue;
1114 
1115  /* We have at least one live child. */
1116  has_live_children = true;
1117 
1118  /*
1119  * If any live child is not parallel-safe, treat the whole appendrel
1120  * as not parallel-safe. In future we might be able to generate plans
1121  * in which some children are farmed out to workers while others are
1122  * not; but we don't have that today, so it's a waste to consider
1123  * partial paths anywhere in the appendrel unless it's all safe.
1124  * (Child rels visited before this one will be unmarked in
1125  * set_append_rel_pathlist().)
1126  */
1127  if (!childrel->consider_parallel)
1128  rel->consider_parallel = false;
1129 
1130  /*
1131  * Accumulate size information from each live child.
1132  */
1133  Assert(childrel->rows > 0);
1134 
1135  parent_rows += childrel->rows;
1136  parent_size += childrel->reltarget->width * childrel->rows;
1137 
1138  /*
1139  * Accumulate per-column estimates too. We need not do anything for
1140  * PlaceHolderVars in the parent list. If child expression isn't a
1141  * Var, or we didn't record a width estimate for it, we have to fall
1142  * back on a datatype-based estimate.
1143  *
1144  * By construction, child's targetlist is 1-to-1 with parent's.
1145  */
1146  forboth(parentvars, rel->reltarget->exprs,
1147  childvars, childrel->reltarget->exprs)
1148  {
1149  Var *parentvar = (Var *) lfirst(parentvars);
1150  Node *childvar = (Node *) lfirst(childvars);
1151 
1152  if (IsA(parentvar, Var) && parentvar->varno == parentRTindex)
1153  {
1154  int pndx = parentvar->varattno - rel->min_attr;
1155  int32 child_width = 0;
1156 
1157  if (IsA(childvar, Var) &&
1158  ((Var *) childvar)->varno == childrel->relid)
1159  {
1160  int cndx = ((Var *) childvar)->varattno - childrel->min_attr;
1161 
1162  child_width = childrel->attr_widths[cndx];
1163  }
1164  if (child_width <= 0)
1165  child_width = get_typavgwidth(exprType(childvar),
1166  exprTypmod(childvar));
1167  Assert(child_width > 0);
1168  parent_attrsizes[pndx] += child_width * childrel->rows;
1169  }
1170  }
1171  }
1172 
1173  if (has_live_children)
1174  {
1175  /*
1176  * Save the finished size estimates.
1177  */
1178  int i;
1179 
1180  Assert(parent_rows > 0);
1181  rel->rows = parent_rows;
1182  rel->reltarget->width = rint(parent_size / parent_rows);
1183  for (i = 0; i < nattrs; i++)
1184  rel->attr_widths[i] = rint(parent_attrsizes[i] / parent_rows);
1185 
1186  /*
1187  * Set "raw tuples" count equal to "rows" for the appendrel; needed
1188  * because some places assume rel->tuples is valid for any baserel.
1189  */
1190  rel->tuples = parent_rows;
1191 
1192  /*
1193  * Note that we leave rel->pages as zero; this is important to avoid
1194  * double-counting the appendrel tree in total_table_pages.
1195  */
1196  }
1197  else
1198  {
1199  /*
1200  * All children were excluded by constraints, so mark the whole
1201  * appendrel dummy. We must do this in this phase so that the rel's
1202  * dummy-ness is visible when we generate paths for other rels.
1203  */
1205  }
1206 
1207  pfree(parent_attrsizes);
1208 }
1209 
1210 /*
1211  * set_append_rel_pathlist
1212  * Build access paths for an "append relation"
1213  */
1214 static void
1216  Index rti, RangeTblEntry *rte)
1217 {
1218  int parentRTindex = rti;
1219  List *live_childrels = NIL;
1220  ListCell *l;
1221 
1222  /*
1223  * Generate access paths for each member relation, and remember the
1224  * non-dummy children.
1225  */
1226  foreach(l, root->append_rel_list)
1227  {
1228  AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
1229  int childRTindex;
1230  RangeTblEntry *childRTE;
1231  RelOptInfo *childrel;
1232 
1233  /* append_rel_list contains all append rels; ignore others */
1234  if (appinfo->parent_relid != parentRTindex)
1235  continue;
1236 
1237  /* Re-locate the child RTE and RelOptInfo */
1238  childRTindex = appinfo->child_relid;
1239  childRTE = root->simple_rte_array[childRTindex];
1240  childrel = root->simple_rel_array[childRTindex];
1241 
1242  /*
1243  * If set_append_rel_size() decided the parent appendrel was
1244  * parallel-unsafe at some point after visiting this child rel, we
1245  * need to propagate the unsafety marking down to the child, so that
1246  * we don't generate useless partial paths for it.
1247  */
1248  if (!rel->consider_parallel)
1249  childrel->consider_parallel = false;
1250 
1251  /*
1252  * Compute the child's access paths.
1253  */
1254  set_rel_pathlist(root, childrel, childRTindex, childRTE);
1255 
1256  /*
1257  * If child is dummy, ignore it.
1258  */
1259  if (IS_DUMMY_REL(childrel))
1260  continue;
1261 
1262  /*
1263  * Child is live, so add it to the live_childrels list for use below.
1264  */
1265  live_childrels = lappend(live_childrels, childrel);
1266  }
1267 
1268  /* Add paths to the append relation. */
1269  add_paths_to_append_rel(root, rel, live_childrels);
1270 }
1271 
1272 
1273 /*
1274  * add_paths_to_append_rel
1275  * Generate paths for the given append relation given the set of non-dummy
1276  * child rels.
1277  *
1278  * The function collects all parameterizations and orderings supported by the
1279  * non-dummy children. For every such parameterization or ordering, it creates
1280  * an append path collecting one path from each non-dummy child with given
1281  * parameterization or ordering. Similarly it collects partial paths from
1282  * non-dummy children to create partial append paths.
1283  */
1284 void
1286  List *live_childrels)
1287 {
1288  List *subpaths = NIL;
1289  bool subpaths_valid = true;
1290  List *partial_subpaths = NIL;
1291  List *pa_partial_subpaths = NIL;
1292  List *pa_nonpartial_subpaths = NIL;
1293  bool partial_subpaths_valid = true;
1294  bool pa_subpaths_valid;
1295  List *all_child_pathkeys = NIL;
1296  List *all_child_outers = NIL;
1297  ListCell *l;
1298  double partial_rows = -1;
1299 
1300  /* If appropriate, consider parallel append */
1301  pa_subpaths_valid = enable_parallel_append && rel->consider_parallel;
1302 
1303  /*
1304  * For every non-dummy child, remember the cheapest path. Also, identify
1305  * all pathkeys (orderings) and parameterizations (required_outer sets)
1306  * available for the non-dummy member relations.
1307  */
1308  foreach(l, live_childrels)
1309  {
1310  RelOptInfo *childrel = lfirst(l);
1311  ListCell *lcp;
1312  Path *cheapest_partial_path = NULL;
1313 
1314  /*
1315  * If child has an unparameterized cheapest-total path, add that to
1316  * the unparameterized Append path we are constructing for the parent.
1317  * If not, there's no workable unparameterized path.
1318  *
1319  * With partitionwise aggregates, the child rel's pathlist may be
1320  * empty, so don't assume that a path exists here.
1321  */
1322  if (childrel->pathlist != NIL &&
1323  childrel->cheapest_total_path->param_info == NULL)
1325  &subpaths, NULL);
1326  else
1327  subpaths_valid = false;
1328 
1329  /* Same idea, but for a partial plan. */
1330  if (childrel->partial_pathlist != NIL)
1331  {
1332  cheapest_partial_path = linitial(childrel->partial_pathlist);
1333  accumulate_append_subpath(cheapest_partial_path,
1334  &partial_subpaths, NULL);
1335  }
1336  else
1337  partial_subpaths_valid = false;
1338 
1339  /*
1340  * Same idea, but for a parallel append mixing partial and non-partial
1341  * paths.
1342  */
1343  if (pa_subpaths_valid)
1344  {
1345  Path *nppath = NULL;
1346 
1347  nppath =
1349 
1350  if (cheapest_partial_path == NULL && nppath == NULL)
1351  {
1352  /* Neither a partial nor a parallel-safe path? Forget it. */
1353  pa_subpaths_valid = false;
1354  }
1355  else if (nppath == NULL ||
1356  (cheapest_partial_path != NULL &&
1357  cheapest_partial_path->total_cost < nppath->total_cost))
1358  {
1359  /* Partial path is cheaper or the only option. */
1360  Assert(cheapest_partial_path != NULL);
1361  accumulate_append_subpath(cheapest_partial_path,
1362  &pa_partial_subpaths,
1363  &pa_nonpartial_subpaths);
1364  }
1365  else
1366  {
1367  /*
1368  * Either we've got only a non-partial path, or we think that
1369  * a single backend can execute the best non-partial path
1370  * faster than all the parallel backends working together can
1371  * execute the best partial path.
1372  *
1373  * It might make sense to be more aggressive here. Even if
1374  * the best non-partial path is more expensive than the best
1375  * partial path, it could still be better to choose the
1376  * non-partial path if there are several such paths that can
1377  * be given to different workers. For now, we don't try to
1378  * figure that out.
1379  */
1381  &pa_nonpartial_subpaths,
1382  NULL);
1383  }
1384  }
1385 
1386  /*
1387  * Collect lists of all the available path orderings and
1388  * parameterizations for all the children. We use these as a
1389  * heuristic to indicate which sort orderings and parameterizations we
1390  * should build Append and MergeAppend paths for.
1391  */
1392  foreach(lcp, childrel->pathlist)
1393  {
1394  Path *childpath = (Path *) lfirst(lcp);
1395  List *childkeys = childpath->pathkeys;
1396  Relids childouter = PATH_REQ_OUTER(childpath);
1397 
1398  /* Unsorted paths don't contribute to pathkey list */
1399  if (childkeys != NIL)
1400  {
1401  ListCell *lpk;
1402  bool found = false;
1403 
1404  /* Have we already seen this ordering? */
1405  foreach(lpk, all_child_pathkeys)
1406  {
1407  List *existing_pathkeys = (List *) lfirst(lpk);
1408 
1409  if (compare_pathkeys(existing_pathkeys,
1410  childkeys) == PATHKEYS_EQUAL)
1411  {
1412  found = true;
1413  break;
1414  }
1415  }
1416  if (!found)
1417  {
1418  /* No, so add it to all_child_pathkeys */
1419  all_child_pathkeys = lappend(all_child_pathkeys,
1420  childkeys);
1421  }
1422  }
1423 
1424  /* Unparameterized paths don't contribute to param-set list */
1425  if (childouter)
1426  {
1427  ListCell *lco;
1428  bool found = false;
1429 
1430  /* Have we already seen this param set? */
1431  foreach(lco, all_child_outers)
1432  {
1433  Relids existing_outers = (Relids) lfirst(lco);
1434 
1435  if (bms_equal(existing_outers, childouter))
1436  {
1437  found = true;
1438  break;
1439  }
1440  }
1441  if (!found)
1442  {
1443  /* No, so add it to all_child_outers */
1444  all_child_outers = lappend(all_child_outers,
1445  childouter);
1446  }
1447  }
1448  }
1449  }
1450 
1451  /*
1452  * If we found unparameterized paths for all children, build an unordered,
1453  * unparameterized Append path for the rel. (Note: this is correct even
1454  * if we have zero or one live subpath due to constraint exclusion.)
1455  */
1456  if (subpaths_valid)
1457  add_path(rel, (Path *) create_append_path(root, rel, subpaths, NIL,
1458  NIL, NULL, 0, false,
1459  -1));
1460 
1461  /*
1462  * Consider an append of unordered, unparameterized partial paths. Make
1463  * it parallel-aware if possible.
1464  */
1465  if (partial_subpaths_valid && partial_subpaths != NIL)
1466  {
1467  AppendPath *appendpath;
1468  ListCell *lc;
1469  int parallel_workers = 0;
1470 
1471  /* Find the highest number of workers requested for any subpath. */
1472  foreach(lc, partial_subpaths)
1473  {
1474  Path *path = lfirst(lc);
1475 
1476  parallel_workers = Max(parallel_workers, path->parallel_workers);
1477  }
1478  Assert(parallel_workers > 0);
1479 
1480  /*
1481  * If the use of parallel append is permitted, always request at least
1482  * log2(# of children) workers. We assume it can be useful to have
1483  * extra workers in this case because they will be spread out across
1484  * the children. The precise formula is just a guess, but we don't
1485  * want to end up with a radically different answer for a table with N
1486  * partitions vs. an unpartitioned table with the same data, so the
1487  * use of some kind of log-scaling here seems to make some sense.
1488  */
1490  {
1491  parallel_workers = Max(parallel_workers,
1492  fls(list_length(live_childrels)));
1493  parallel_workers = Min(parallel_workers,
1495  }
1496  Assert(parallel_workers > 0);
1497 
1498  /* Generate a partial append path. */
1499  appendpath = create_append_path(root, rel, NIL, partial_subpaths,
1500  NIL, NULL, parallel_workers,
1502  -1);
1503 
1504  /*
1505  * Make sure any subsequent partial paths use the same row count
1506  * estimate.
1507  */
1508  partial_rows = appendpath->path.rows;
1509 
1510  /* Add the path. */
1511  add_partial_path(rel, (Path *) appendpath);
1512  }
1513 
1514  /*
1515  * Consider a parallel-aware append using a mix of partial and non-partial
1516  * paths. (This only makes sense if there's at least one child which has
1517  * a non-partial path that is substantially cheaper than any partial path;
1518  * otherwise, we should use the append path added in the previous step.)
1519  */
1520  if (pa_subpaths_valid && pa_nonpartial_subpaths != NIL)
1521  {
1522  AppendPath *appendpath;
1523  ListCell *lc;
1524  int parallel_workers = 0;
1525 
1526  /*
1527  * Find the highest number of workers requested for any partial
1528  * subpath.
1529  */
1530  foreach(lc, pa_partial_subpaths)
1531  {
1532  Path *path = lfirst(lc);
1533 
1534  parallel_workers = Max(parallel_workers, path->parallel_workers);
1535  }
1536 
1537  /*
1538  * Same formula here as above. It's even more important in this
1539  * instance because the non-partial paths won't contribute anything to
1540  * the planned number of parallel workers.
1541  */
1542  parallel_workers = Max(parallel_workers,
1543  fls(list_length(live_childrels)));
1544  parallel_workers = Min(parallel_workers,
1546  Assert(parallel_workers > 0);
1547 
1548  appendpath = create_append_path(root, rel, pa_nonpartial_subpaths,
1549  pa_partial_subpaths,
1550  NIL, NULL, parallel_workers, true,
1551  partial_rows);
1552  add_partial_path(rel, (Path *) appendpath);
1553  }
1554 
1555  /*
1556  * Also build unparameterized ordered append paths based on the collected
1557  * list of child pathkeys.
1558  */
1559  if (subpaths_valid)
1560  generate_orderedappend_paths(root, rel, live_childrels,
1561  all_child_pathkeys);
1562 
1563  /*
1564  * Build Append paths for each parameterization seen among the child rels.
1565  * (This may look pretty expensive, but in most cases of practical
1566  * interest, the child rels will expose mostly the same parameterizations,
1567  * so that not that many cases actually get considered here.)
1568  *
1569  * The Append node itself cannot enforce quals, so all qual checking must
1570  * be done in the child paths. This means that to have a parameterized
1571  * Append path, we must have the exact same parameterization for each
1572  * child path; otherwise some children might be failing to check the
1573  * moved-down quals. To make them match up, we can try to increase the
1574  * parameterization of lesser-parameterized paths.
1575  */
1576  foreach(l, all_child_outers)
1577  {
1578  Relids required_outer = (Relids) lfirst(l);
1579  ListCell *lcr;
1580 
1581  /* Select the child paths for an Append with this parameterization */
1582  subpaths = NIL;
1583  subpaths_valid = true;
1584  foreach(lcr, live_childrels)
1585  {
1586  RelOptInfo *childrel = (RelOptInfo *) lfirst(lcr);
1587  Path *subpath;
1588 
1589  if (childrel->pathlist == NIL)
1590  {
1591  /* failed to make a suitable path for this child */
1592  subpaths_valid = false;
1593  break;
1594  }
1595 
1597  childrel,
1598  required_outer);
1599  if (subpath == NULL)
1600  {
1601  /* failed to make a suitable path for this child */
1602  subpaths_valid = false;
1603  break;
1604  }
1605  accumulate_append_subpath(subpath, &subpaths, NULL);
1606  }
1607 
1608  if (subpaths_valid)
1609  add_path(rel, (Path *)
1610  create_append_path(root, rel, subpaths, NIL,
1611  NIL, required_outer, 0, false,
1612  -1));
1613  }
1614 
1615  /*
1616  * When there is only a single child relation, the Append path can inherit
1617  * any ordering available for the child rel's path, so that it's useful to
1618  * consider ordered partial paths. Above we only considered the cheapest
1619  * partial path for each child, but let's also make paths using any
1620  * partial paths that have pathkeys.
1621  */
1622  if (list_length(live_childrels) == 1)
1623  {
1624  RelOptInfo *childrel = (RelOptInfo *) linitial(live_childrels);
1625 
1626  /* skip the cheapest partial path, since we already used that above */
1627  for_each_from(l, childrel->partial_pathlist, 1)
1628  {
1629  Path *path = (Path *) lfirst(l);
1630  AppendPath *appendpath;
1631 
1632  /* skip paths with no pathkeys. */
1633  if (path->pathkeys == NIL)
1634  continue;
1635 
1636  appendpath = create_append_path(root, rel, NIL, list_make1(path),
1637  NIL, NULL,
1638  path->parallel_workers, true,
1639  partial_rows);
1640  add_partial_path(rel, (Path *) appendpath);
1641  }
1642  }
1643 }
1644 
1645 /*
1646  * generate_orderedappend_paths
1647  * Generate ordered append paths for an append relation
1648  *
1649  * Usually we generate MergeAppend paths here, but there are some special
1650  * cases where we can generate simple Append paths, because the subpaths
1651  * can provide tuples in the required order already.
1652  *
1653  * We generate a path for each ordering (pathkey list) appearing in
1654  * all_child_pathkeys.
1655  *
1656  * We consider both cheapest-startup and cheapest-total cases, ie, for each
1657  * interesting ordering, collect all the cheapest startup subpaths and all the
1658  * cheapest total paths, and build a suitable path for each case.
1659  *
1660  * We don't currently generate any parameterized ordered paths here. While
1661  * it would not take much more code here to do so, it's very unclear that it
1662  * is worth the planning cycles to investigate such paths: there's little
1663  * use for an ordered path on the inside of a nestloop. In fact, it's likely
1664  * that the current coding of add_path would reject such paths out of hand,
1665  * because add_path gives no credit for sort ordering of parameterized paths,
1666  * and a parameterized MergeAppend is going to be more expensive than the
1667  * corresponding parameterized Append path. If we ever try harder to support
1668  * parameterized mergejoin plans, it might be worth adding support for
1669  * parameterized paths here to feed such joins. (See notes in
1670  * optimizer/README for why that might not ever happen, though.)
1671  */
1672 static void
1674  List *live_childrels,
1675  List *all_child_pathkeys)
1676 {
1677  ListCell *lcp;
1678  List *partition_pathkeys = NIL;
1679  List *partition_pathkeys_desc = NIL;
1680  bool partition_pathkeys_partial = true;
1681  bool partition_pathkeys_desc_partial = true;
1682 
1683  /*
1684  * Some partitioned table setups may allow us to use an Append node
1685  * instead of a MergeAppend. This is possible in cases such as RANGE
1686  * partitioned tables where it's guaranteed that an earlier partition must
1687  * contain rows which come earlier in the sort order. To detect whether
1688  * this is relevant, build pathkey descriptions of the partition ordering,
1689  * for both forward and reverse scans.
1690  */
1691  if (rel->part_scheme != NULL && IS_SIMPLE_REL(rel) &&
1693  {
1694  partition_pathkeys = build_partition_pathkeys(root, rel,
1696  &partition_pathkeys_partial);
1697 
1698  partition_pathkeys_desc = build_partition_pathkeys(root, rel,
1700  &partition_pathkeys_desc_partial);
1701 
1702  /*
1703  * You might think we should truncate_useless_pathkeys here, but
1704  * allowing partition keys which are a subset of the query's pathkeys
1705  * can often be useful. For example, consider a table partitioned by
1706  * RANGE (a, b), and a query with ORDER BY a, b, c. If we have child
1707  * paths that can produce the a, b, c ordering (perhaps via indexes on
1708  * (a, b, c)) then it works to consider the appendrel output as
1709  * ordered by a, b, c.
1710  */
1711  }
1712 
1713  /* Now consider each interesting sort ordering */
1714  foreach(lcp, all_child_pathkeys)
1715  {
1716  List *pathkeys = (List *) lfirst(lcp);
1717  List *startup_subpaths = NIL;
1718  List *total_subpaths = NIL;
1719  bool startup_neq_total = false;
1720  ListCell *lcr;
1721  bool match_partition_order;
1722  bool match_partition_order_desc;
1723 
1724  /*
1725  * Determine if this sort ordering matches any partition pathkeys we
1726  * have, for both ascending and descending partition order. If the
1727  * partition pathkeys happen to be contained in pathkeys then it still
1728  * works, as described above, providing that the partition pathkeys
1729  * are complete and not just a prefix of the partition keys. (In such
1730  * cases we'll be relying on the child paths to have sorted the
1731  * lower-order columns of the required pathkeys.)
1732  */
1733  match_partition_order =
1734  pathkeys_contained_in(pathkeys, partition_pathkeys) ||
1735  (!partition_pathkeys_partial &&
1736  pathkeys_contained_in(partition_pathkeys, pathkeys));
1737 
1738  match_partition_order_desc = !match_partition_order &&
1739  (pathkeys_contained_in(pathkeys, partition_pathkeys_desc) ||
1740  (!partition_pathkeys_desc_partial &&
1741  pathkeys_contained_in(partition_pathkeys_desc, pathkeys)));
1742 
1743  /* Select the child paths for this ordering... */
1744  foreach(lcr, live_childrels)
1745  {
1746  RelOptInfo *childrel = (RelOptInfo *) lfirst(lcr);
1747  Path *cheapest_startup,
1748  *cheapest_total;
1749 
1750  /* Locate the right paths, if they are available. */
1751  cheapest_startup =
1753  pathkeys,
1754  NULL,
1755  STARTUP_COST,
1756  false);
1757  cheapest_total =
1759  pathkeys,
1760  NULL,
1761  TOTAL_COST,
1762  false);
1763 
1764  /*
1765  * If we can't find any paths with the right order just use the
1766  * cheapest-total path; we'll have to sort it later.
1767  */
1768  if (cheapest_startup == NULL || cheapest_total == NULL)
1769  {
1770  cheapest_startup = cheapest_total =
1771  childrel->cheapest_total_path;
1772  /* Assert we do have an unparameterized path for this child */
1773  Assert(cheapest_total->param_info == NULL);
1774  }
1775 
1776  /*
1777  * Notice whether we actually have different paths for the
1778  * "cheapest" and "total" cases; frequently there will be no point
1779  * in two create_merge_append_path() calls.
1780  */
1781  if (cheapest_startup != cheapest_total)
1782  startup_neq_total = true;
1783 
1784  /*
1785  * Collect the appropriate child paths. The required logic varies
1786  * for the Append and MergeAppend cases.
1787  */
1788  if (match_partition_order)
1789  {
1790  /*
1791  * We're going to make a plain Append path. We don't need
1792  * most of what accumulate_append_subpath would do, but we do
1793  * want to cut out child Appends or MergeAppends if they have
1794  * just a single subpath (and hence aren't doing anything
1795  * useful).
1796  */
1797  cheapest_startup = get_singleton_append_subpath(cheapest_startup);
1798  cheapest_total = get_singleton_append_subpath(cheapest_total);
1799 
1800  startup_subpaths = lappend(startup_subpaths, cheapest_startup);
1801  total_subpaths = lappend(total_subpaths, cheapest_total);
1802  }
1803  else if (match_partition_order_desc)
1804  {
1805  /*
1806  * As above, but we need to reverse the order of the children,
1807  * because nodeAppend.c doesn't know anything about reverse
1808  * ordering and will scan the children in the order presented.
1809  */
1810  cheapest_startup = get_singleton_append_subpath(cheapest_startup);
1811  cheapest_total = get_singleton_append_subpath(cheapest_total);
1812 
1813  startup_subpaths = lcons(cheapest_startup, startup_subpaths);
1814  total_subpaths = lcons(cheapest_total, total_subpaths);
1815  }
1816  else
1817  {
1818  /*
1819  * Otherwise, rely on accumulate_append_subpath to collect the
1820  * child paths for the MergeAppend.
1821  */
1822  accumulate_append_subpath(cheapest_startup,
1823  &startup_subpaths, NULL);
1824  accumulate_append_subpath(cheapest_total,
1825  &total_subpaths, NULL);
1826  }
1827  }
1828 
1829  /* ... and build the Append or MergeAppend paths */
1830  if (match_partition_order || match_partition_order_desc)
1831  {
1832  /* We only need Append */
1833  add_path(rel, (Path *) create_append_path(root,
1834  rel,
1835  startup_subpaths,
1836  NIL,
1837  pathkeys,
1838  NULL,
1839  0,
1840  false,
1841  -1));
1842  if (startup_neq_total)
1843  add_path(rel, (Path *) create_append_path(root,
1844  rel,
1845  total_subpaths,
1846  NIL,
1847  pathkeys,
1848  NULL,
1849  0,
1850  false,
1851  -1));
1852  }
1853  else
1854  {
1855  /* We need MergeAppend */
1856  add_path(rel, (Path *) create_merge_append_path(root,
1857  rel,
1858  startup_subpaths,
1859  pathkeys,
1860  NULL));
1861  if (startup_neq_total)
1862  add_path(rel, (Path *) create_merge_append_path(root,
1863  rel,
1864  total_subpaths,
1865  pathkeys,
1866  NULL));
1867  }
1868  }
1869 }
1870 
1871 /*
1872  * get_cheapest_parameterized_child_path
1873  * Get cheapest path for this relation that has exactly the requested
1874  * parameterization.
1875  *
1876  * Returns NULL if unable to create such a path.
1877  */
1878 static Path *
1880  Relids required_outer)
1881 {
1882  Path *cheapest;
1883  ListCell *lc;
1884 
1885  /*
1886  * Look up the cheapest existing path with no more than the needed
1887  * parameterization. If it has exactly the needed parameterization, we're
1888  * done.
1889  */
1890  cheapest = get_cheapest_path_for_pathkeys(rel->pathlist,
1891  NIL,
1892  required_outer,
1893  TOTAL_COST,
1894  false);
1895  Assert(cheapest != NULL);
1896  if (bms_equal(PATH_REQ_OUTER(cheapest), required_outer))
1897  return cheapest;
1898 
1899  /*
1900  * Otherwise, we can "reparameterize" an existing path to match the given
1901  * parameterization, which effectively means pushing down additional
1902  * joinquals to be checked within the path's scan. However, some existing
1903  * paths might check the available joinquals already while others don't;
1904  * therefore, it's not clear which existing path will be cheapest after
1905  * reparameterization. We have to go through them all and find out.
1906  */
1907  cheapest = NULL;
1908  foreach(lc, rel->pathlist)
1909  {
1910  Path *path = (Path *) lfirst(lc);
1911 
1912  /* Can't use it if it needs more than requested parameterization */
1913  if (!bms_is_subset(PATH_REQ_OUTER(path), required_outer))
1914  continue;
1915 
1916  /*
1917  * Reparameterization can only increase the path's cost, so if it's
1918  * already more expensive than the current cheapest, forget it.
1919  */
1920  if (cheapest != NULL &&
1921  compare_path_costs(cheapest, path, TOTAL_COST) <= 0)
1922  continue;
1923 
1924  /* Reparameterize if needed, then recheck cost */
1925  if (!bms_equal(PATH_REQ_OUTER(path), required_outer))
1926  {
1927  path = reparameterize_path(root, path, required_outer, 1.0);
1928  if (path == NULL)
1929  continue; /* failed to reparameterize this one */
1930  Assert(bms_equal(PATH_REQ_OUTER(path), required_outer));
1931 
1932  if (cheapest != NULL &&
1933  compare_path_costs(cheapest, path, TOTAL_COST) <= 0)
1934  continue;
1935  }
1936 
1937  /* We have a new best path */
1938  cheapest = path;
1939  }
1940 
1941  /* Return the best path, or NULL if we found no suitable candidate */
1942  return cheapest;
1943 }
1944 
1945 /*
1946  * accumulate_append_subpath
1947  * Add a subpath to the list being built for an Append or MergeAppend.
1948  *
1949  * It's possible that the child is itself an Append or MergeAppend path, in
1950  * which case we can "cut out the middleman" and just add its child paths to
1951  * our own list. (We don't try to do this earlier because we need to apply
1952  * both levels of transformation to the quals.)
1953  *
1954  * Note that if we omit a child MergeAppend in this way, we are effectively
1955  * omitting a sort step, which seems fine: if the parent is to be an Append,
1956  * its result would be unsorted anyway, while if the parent is to be a
1957  * MergeAppend, there's no point in a separate sort on a child.
1958  *
1959  * Normally, either path is a partial path and subpaths is a list of partial
1960  * paths, or else path is a non-partial plan and subpaths is a list of those.
1961  * However, if path is a parallel-aware Append, then we add its partial path
1962  * children to subpaths and the rest to special_subpaths. If the latter is
1963  * NULL, we don't flatten the path at all (unless it contains only partial
1964  * paths).
1965  */
1966 static void
1967 accumulate_append_subpath(Path *path, List **subpaths, List **special_subpaths)
1968 {
1969  if (IsA(path, AppendPath))
1970  {
1971  AppendPath *apath = (AppendPath *) path;
1972 
1973  if (!apath->path.parallel_aware || apath->first_partial_path == 0)
1974  {
1975  *subpaths = list_concat(*subpaths, apath->subpaths);
1976  return;
1977  }
1978  else if (special_subpaths != NULL)
1979  {
1980  List *new_special_subpaths;
1981 
1982  /* Split Parallel Append into partial and non-partial subpaths */
1983  *subpaths = list_concat(*subpaths,
1984  list_copy_tail(apath->subpaths,
1985  apath->first_partial_path));
1986  new_special_subpaths =
1988  apath->first_partial_path);
1989  *special_subpaths = list_concat(*special_subpaths,
1990  new_special_subpaths);
1991  return;
1992  }
1993  }
1994  else if (IsA(path, MergeAppendPath))
1995  {
1996  MergeAppendPath *mpath = (MergeAppendPath *) path;
1997 
1998  *subpaths = list_concat(*subpaths, mpath->subpaths);
1999  return;
2000  }
2001 
2002  *subpaths = lappend(*subpaths, path);
2003 }
2004 
2005 /*
2006  * get_singleton_append_subpath
2007  * Returns the single subpath of an Append/MergeAppend, or just
2008  * return 'path' if it's not a single sub-path Append/MergeAppend.
2009  *
2010  * Note: 'path' must not be a parallel-aware path.
2011  */
2012 static Path *
2014 {
2015  Assert(!path->parallel_aware);
2016 
2017  if (IsA(path, AppendPath))
2018  {
2019  AppendPath *apath = (AppendPath *) path;
2020 
2021  if (list_length(apath->subpaths) == 1)
2022  return (Path *) linitial(apath->subpaths);
2023  }
2024  else if (IsA(path, MergeAppendPath))
2025  {
2026  MergeAppendPath *mpath = (MergeAppendPath *) path;
2027 
2028  if (list_length(mpath->subpaths) == 1)
2029  return (Path *) linitial(mpath->subpaths);
2030  }
2031 
2032  return path;
2033 }
2034 
2035 /*
2036  * set_dummy_rel_pathlist
2037  * Build a dummy path for a relation that's been excluded by constraints
2038  *
2039  * Rather than inventing a special "dummy" path type, we represent this as an
2040  * AppendPath with no members (see also IS_DUMMY_APPEND/IS_DUMMY_REL macros).
2041  *
2042  * (See also mark_dummy_rel, which does basically the same thing, but is
2043  * typically used to change a rel into dummy state after we already made
2044  * paths for it.)
2045  */
2046 static void
2048 {
2049  /* Set dummy size estimates --- we leave attr_widths[] as zeroes */
2050  rel->rows = 0;
2051  rel->reltarget->width = 0;
2052 
2053  /* Discard any pre-existing paths; no further need for them */
2054  rel->pathlist = NIL;
2055  rel->partial_pathlist = NIL;
2056 
2057  /* Set up the dummy path */
2058  add_path(rel, (Path *) create_append_path(NULL, rel, NIL, NIL,
2059  NIL, rel->lateral_relids,
2060  0, false, -1));
2061 
2062  /*
2063  * We set the cheapest-path fields immediately, just in case they were
2064  * pointing at some discarded path. This is redundant when we're called
2065  * from set_rel_size(), but not when called from elsewhere, and doing it
2066  * twice is harmless anyway.
2067  */
2068  set_cheapest(rel);
2069 }
2070 
2071 /* quick-and-dirty test to see if any joining is needed */
2072 static bool
2074 {
2075  int num_base_rels = 0;
2076  Index rti;
2077 
2078  for (rti = 1; rti < root->simple_rel_array_size; rti++)
2079  {
2080  RelOptInfo *brel = root->simple_rel_array[rti];
2081 
2082  if (brel == NULL)
2083  continue;
2084 
2085  /* ignore RTEs that are "other rels" */
2086  if (brel->reloptkind == RELOPT_BASEREL)
2087  if (++num_base_rels > 1)
2088  return true;
2089  }
2090  return false;
2091 }
2092 
2093 /*
2094  * set_subquery_pathlist
2095  * Generate SubqueryScan access paths for a subquery RTE
2096  *
2097  * We don't currently support generating parameterized paths for subqueries
2098  * by pushing join clauses down into them; it seems too expensive to re-plan
2099  * the subquery multiple times to consider different alternatives.
2100  * (XXX that could stand to be reconsidered, now that we use Paths.)
2101  * So the paths made here will be parameterized if the subquery contains
2102  * LATERAL references, otherwise not. As long as that's true, there's no need
2103  * for a separate set_subquery_size phase: just make the paths right away.
2104  */
2105 static void
2107  Index rti, RangeTblEntry *rte)
2108 {
2109  Query *parse = root->parse;
2110  Query *subquery = rte->subquery;
2111  Relids required_outer;
2112  pushdown_safety_info safetyInfo;
2113  double tuple_fraction;
2114  RelOptInfo *sub_final_rel;
2115  ListCell *lc;
2116 
2117  /*
2118  * Must copy the Query so that planning doesn't mess up the RTE contents
2119  * (really really need to fix the planner to not scribble on its input,
2120  * someday ... but see remove_unused_subquery_outputs to start with).
2121  */
2122  subquery = copyObject(subquery);
2123 
2124  /*
2125  * If it's a LATERAL subquery, it might contain some Vars of the current
2126  * query level, requiring it to be treated as parameterized, even though
2127  * we don't support pushing down join quals into subqueries.
2128  */
2129  required_outer = rel->lateral_relids;
2130 
2131  /*
2132  * Zero out result area for subquery_is_pushdown_safe, so that it can set
2133  * flags as needed while recursing. In particular, we need a workspace
2134  * for keeping track of unsafe-to-reference columns. unsafeColumns[i]
2135  * will be set true if we find that output column i of the subquery is
2136  * unsafe to use in a pushed-down qual.
2137  */
2138  memset(&safetyInfo, 0, sizeof(safetyInfo));
2139  safetyInfo.unsafeColumns = (bool *)
2140  palloc0((list_length(subquery->targetList) + 1) * sizeof(bool));
2141 
2142  /*
2143  * If the subquery has the "security_barrier" flag, it means the subquery
2144  * originated from a view that must enforce row-level security. Then we
2145  * must not push down quals that contain leaky functions. (Ideally this
2146  * would be checked inside subquery_is_pushdown_safe, but since we don't
2147  * currently pass the RTE to that function, we must do it here.)
2148  */
2149  safetyInfo.unsafeLeaky = rte->security_barrier;
2150 
2151  /*
2152  * If there are any restriction clauses that have been attached to the
2153  * subquery relation, consider pushing them down to become WHERE or HAVING
2154  * quals of the subquery itself. This transformation is useful because it
2155  * may allow us to generate a better plan for the subquery than evaluating
2156  * all the subquery output rows and then filtering them.
2157  *
2158  * There are several cases where we cannot push down clauses. Restrictions
2159  * involving the subquery are checked by subquery_is_pushdown_safe().
2160  * Restrictions on individual clauses are checked by
2161  * qual_is_pushdown_safe(). Also, we don't want to push down
2162  * pseudoconstant clauses; better to have the gating node above the
2163  * subquery.
2164  *
2165  * Non-pushed-down clauses will get evaluated as qpquals of the
2166  * SubqueryScan node.
2167  *
2168  * XXX Are there any cases where we want to make a policy decision not to
2169  * push down a pushable qual, because it'd result in a worse plan?
2170  */
2171  if (rel->baserestrictinfo != NIL &&
2172  subquery_is_pushdown_safe(subquery, subquery, &safetyInfo))
2173  {
2174  /* OK to consider pushing down individual quals */
2175  List *upperrestrictlist = NIL;
2176  ListCell *l;
2177 
2178  foreach(l, rel->baserestrictinfo)
2179  {
2180  RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
2181 
2182  if (!rinfo->pseudoconstant &&
2183  qual_is_pushdown_safe(subquery, rti, rinfo, &safetyInfo))
2184  {
2185  Node *clause = (Node *) rinfo->clause;
2186 
2187  /* Push it down */
2188  subquery_push_qual(subquery, rte, rti, clause);
2189  }
2190  else
2191  {
2192  /* Keep it in the upper query */
2193  upperrestrictlist = lappend(upperrestrictlist, rinfo);
2194  }
2195  }
2196  rel->baserestrictinfo = upperrestrictlist;
2197  /* We don't bother recomputing baserestrict_min_security */
2198  }
2199 
2200  pfree(safetyInfo.unsafeColumns);
2201 
2202  /*
2203  * The upper query might not use all the subquery's output columns; if
2204  * not, we can simplify.
2205  */
2206  remove_unused_subquery_outputs(subquery, rel);
2207 
2208  /*
2209  * We can safely pass the outer tuple_fraction down to the subquery if the
2210  * outer level has no joining, aggregation, or sorting to do. Otherwise
2211  * we'd better tell the subquery to plan for full retrieval. (XXX This
2212  * could probably be made more intelligent ...)
2213  */
2214  if (parse->hasAggs ||
2215  parse->groupClause ||
2216  parse->groupingSets ||
2217  parse->havingQual ||
2218  parse->distinctClause ||
2219  parse->sortClause ||
2220  has_multiple_baserels(root))
2221  tuple_fraction = 0.0; /* default case */
2222  else
2223  tuple_fraction = root->tuple_fraction;
2224 
2225  /* plan_params should not be in use in current query level */
2226  Assert(root->plan_params == NIL);
2227 
2228  /* Generate a subroot and Paths for the subquery */
2229  rel->subroot = subquery_planner(root->glob, subquery,
2230  root,
2231  false, tuple_fraction);
2232 
2233  /* Isolate the params needed by this specific subplan */
2234  rel->subplan_params = root->plan_params;
2235  root->plan_params = NIL;
2236 
2237  /*
2238  * It's possible that constraint exclusion proved the subquery empty. If
2239  * so, it's desirable to produce an unadorned dummy path so that we will
2240  * recognize appropriate optimizations at this query level.
2241  */
2242  sub_final_rel = fetch_upper_rel(rel->subroot, UPPERREL_FINAL, NULL);
2243 
2244  if (IS_DUMMY_REL(sub_final_rel))
2245  {
2247  return;
2248  }
2249 
2250  /*
2251  * Mark rel with estimated output rows, width, etc. Note that we have to
2252  * do this before generating outer-query paths, else cost_subqueryscan is
2253  * not happy.
2254  */
2255  set_subquery_size_estimates(root, rel);
2256 
2257  /*
2258  * For each Path that subquery_planner produced, make a SubqueryScanPath
2259  * in the outer query.
2260  */
2261  foreach(lc, sub_final_rel->pathlist)
2262  {
2263  Path *subpath = (Path *) lfirst(lc);
2264  List *pathkeys;
2265 
2266  /* Convert subpath's pathkeys to outer representation */
2267  pathkeys = convert_subquery_pathkeys(root,
2268  rel,
2269  subpath->pathkeys,
2271 
2272  /* Generate outer path using this subpath */
2273  add_path(rel, (Path *)
2274  create_subqueryscan_path(root, rel, subpath,
2275  pathkeys, required_outer));
2276  }
2277 
2278  /* If outer rel allows parallelism, do same for partial paths. */
2279  if (rel->consider_parallel && bms_is_empty(required_outer))
2280  {
2281  /* If consider_parallel is false, there should be no partial paths. */
2282  Assert(sub_final_rel->consider_parallel ||
2283  sub_final_rel->partial_pathlist == NIL);
2284 
2285  /* Same for partial paths. */
2286  foreach(lc, sub_final_rel->partial_pathlist)
2287  {
2288  Path *subpath = (Path *) lfirst(lc);
2289  List *pathkeys;
2290 
2291  /* Convert subpath's pathkeys to outer representation */
2292  pathkeys = convert_subquery_pathkeys(root,
2293  rel,
2294  subpath->pathkeys,
2296 
2297  /* Generate outer path using this subpath */
2298  add_partial_path(rel, (Path *)
2299  create_subqueryscan_path(root, rel, subpath,
2300  pathkeys,
2301  required_outer));
2302  }
2303  }
2304 }
2305 
2306 /*
2307  * set_function_pathlist
2308  * Build the (single) access path for a function RTE
2309  */
2310 static void
2312 {
2313  Relids required_outer;
2314  List *pathkeys = NIL;
2315 
2316  /*
2317  * We don't support pushing join clauses into the quals of a function
2318  * scan, but it could still have required parameterization due to LATERAL
2319  * refs in the function expression.
2320  */
2321  required_outer = rel->lateral_relids;
2322 
2323  /*
2324  * The result is considered unordered unless ORDINALITY was used, in which
2325  * case it is ordered by the ordinal column (the last one). See if we
2326  * care, by checking for uses of that Var in equivalence classes.
2327  */
2328  if (rte->funcordinality)
2329  {
2330  AttrNumber ordattno = rel->max_attr;
2331  Var *var = NULL;
2332  ListCell *lc;
2333 
2334  /*
2335  * Is there a Var for it in rel's targetlist? If not, the query did
2336  * not reference the ordinality column, or at least not in any way
2337  * that would be interesting for sorting.
2338  */
2339  foreach(lc, rel->reltarget->exprs)
2340  {
2341  Var *node = (Var *) lfirst(lc);
2342 
2343  /* checking varno/varlevelsup is just paranoia */
2344  if (IsA(node, Var) &&
2345  node->varattno == ordattno &&
2346  node->varno == rel->relid &&
2347  node->varlevelsup == 0)
2348  {
2349  var = node;
2350  break;
2351  }
2352  }
2353 
2354  /*
2355  * Try to build pathkeys for this Var with int8 sorting. We tell
2356  * build_expression_pathkey not to build any new equivalence class; if
2357  * the Var isn't already mentioned in some EC, it means that nothing
2358  * cares about the ordering.
2359  */
2360  if (var)
2361  pathkeys = build_expression_pathkey(root,
2362  (Expr *) var,
2363  NULL, /* below outer joins */
2364  Int8LessOperator,
2365  rel->relids,
2366  false);
2367  }
2368 
2369  /* Generate appropriate path */
2370  add_path(rel, create_functionscan_path(root, rel,
2371  pathkeys, required_outer));
2372 }
2373 
2374 /*
2375  * set_values_pathlist
2376  * Build the (single) access path for a VALUES RTE
2377  */
2378 static void
2380 {
2381  Relids required_outer;
2382 
2383  /*
2384  * We don't support pushing join clauses into the quals of a values scan,
2385  * but it could still have required parameterization due to LATERAL refs
2386  * in the values expressions.
2387  */
2388  required_outer = rel->lateral_relids;
2389 
2390  /* Generate appropriate path */
2391  add_path(rel, create_valuesscan_path(root, rel, required_outer));
2392 }
2393 
2394 /*
2395  * set_tablefunc_pathlist
2396  * Build the (single) access path for a table func RTE
2397  */
2398 static void
2400 {
2401  Relids required_outer;
2402 
2403  /*
2404  * We don't support pushing join clauses into the quals of a tablefunc
2405  * scan, but it could still have required parameterization due to LATERAL
2406  * refs in the function expression.
2407  */
2408  required_outer = rel->lateral_relids;
2409 
2410  /* Generate appropriate path */
2411  add_path(rel, create_tablefuncscan_path(root, rel,
2412  required_outer));
2413 }
2414 
2415 /*
2416  * set_cte_pathlist
2417  * Build the (single) access path for a non-self-reference CTE RTE
2418  *
2419  * There's no need for a separate set_cte_size phase, since we don't
2420  * support join-qual-parameterized paths for CTEs.
2421  */
2422 static void
2424 {
2425  Plan *cteplan;
2426  PlannerInfo *cteroot;
2427  Index levelsup;
2428  int ndx;
2429  ListCell *lc;
2430  int plan_id;
2431  Relids required_outer;
2432 
2433  /*
2434  * Find the referenced CTE, and locate the plan previously made for it.
2435  */
2436  levelsup = rte->ctelevelsup;
2437  cteroot = root;
2438  while (levelsup-- > 0)
2439  {
2440  cteroot = cteroot->parent_root;
2441  if (!cteroot) /* shouldn't happen */
2442  elog(ERROR, "bad levelsup for CTE \"%s\"", rte->ctename);
2443  }
2444 
2445  /*
2446  * Note: cte_plan_ids can be shorter than cteList, if we are still working
2447  * on planning the CTEs (ie, this is a side-reference from another CTE).
2448  * So we mustn't use forboth here.
2449  */
2450  ndx = 0;
2451  foreach(lc, cteroot->parse->cteList)
2452  {
2453  CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
2454 
2455  if (strcmp(cte->ctename, rte->ctename) == 0)
2456  break;
2457  ndx++;
2458  }
2459  if (lc == NULL) /* shouldn't happen */
2460  elog(ERROR, "could not find CTE \"%s\"", rte->ctename);
2461  if (ndx >= list_length(cteroot->cte_plan_ids))
2462  elog(ERROR, "could not find plan for CTE \"%s\"", rte->ctename);
2463  plan_id = list_nth_int(cteroot->cte_plan_ids, ndx);
2464  Assert(plan_id > 0);
2465  cteplan = (Plan *) list_nth(root->glob->subplans, plan_id - 1);
2466 
2467  /* Mark rel with estimated output rows, width, etc */
2468  set_cte_size_estimates(root, rel, cteplan->plan_rows);
2469 
2470  /*
2471  * We don't support pushing join clauses into the quals of a CTE scan, but
2472  * it could still have required parameterization due to LATERAL refs in
2473  * its tlist.
2474  */
2475  required_outer = rel->lateral_relids;
2476 
2477  /* Generate appropriate path */
2478  add_path(rel, create_ctescan_path(root, rel, required_outer));
2479 }
2480 
2481 /*
2482  * set_namedtuplestore_pathlist
2483  * Build the (single) access path for a named tuplestore RTE
2484  *
2485  * There's no need for a separate set_namedtuplestore_size phase, since we
2486  * don't support join-qual-parameterized paths for tuplestores.
2487  */
2488 static void
2490  RangeTblEntry *rte)
2491 {
2492  Relids required_outer;
2493 
2494  /* Mark rel with estimated output rows, width, etc */
2496 
2497  /*
2498  * We don't support pushing join clauses into the quals of a tuplestore
2499  * scan, but it could still have required parameterization due to LATERAL
2500  * refs in its tlist.
2501  */
2502  required_outer = rel->lateral_relids;
2503 
2504  /* Generate appropriate path */
2505  add_path(rel, create_namedtuplestorescan_path(root, rel, required_outer));
2506 
2507  /* Select cheapest path (pretty easy in this case...) */
2508  set_cheapest(rel);
2509 }
2510 
2511 /*
2512  * set_result_pathlist
2513  * Build the (single) access path for an RTE_RESULT RTE
2514  *
2515  * There's no need for a separate set_result_size phase, since we
2516  * don't support join-qual-parameterized paths for these RTEs.
2517  */
2518 static void
2520  RangeTblEntry *rte)
2521 {
2522  Relids required_outer;
2523 
2524  /* Mark rel with estimated output rows, width, etc */
2525  set_result_size_estimates(root, rel);
2526 
2527  /*
2528  * We don't support pushing join clauses into the quals of a Result scan,
2529  * but it could still have required parameterization due to LATERAL refs
2530  * in its tlist.
2531  */
2532  required_outer = rel->lateral_relids;
2533 
2534  /* Generate appropriate path */
2535  add_path(rel, create_resultscan_path(root, rel, required_outer));
2536 
2537  /* Select cheapest path (pretty easy in this case...) */
2538  set_cheapest(rel);
2539 }
2540 
2541 /*
2542  * set_worktable_pathlist
2543  * Build the (single) access path for a self-reference CTE RTE
2544  *
2545  * There's no need for a separate set_worktable_size phase, since we don't
2546  * support join-qual-parameterized paths for CTEs.
2547  */
2548 static void
2550 {
2551  Path *ctepath;
2552  PlannerInfo *cteroot;
2553  Index levelsup;
2554  Relids required_outer;
2555 
2556  /*
2557  * We need to find the non-recursive term's path, which is in the plan
2558  * level that's processing the recursive UNION, which is one level *below*
2559  * where the CTE comes from.
2560  */
2561  levelsup = rte->ctelevelsup;
2562  if (levelsup == 0) /* shouldn't happen */
2563  elog(ERROR, "bad levelsup for CTE \"%s\"", rte->ctename);
2564  levelsup--;
2565  cteroot = root;
2566  while (levelsup-- > 0)
2567  {
2568  cteroot = cteroot->parent_root;
2569  if (!cteroot) /* shouldn't happen */
2570  elog(ERROR, "bad levelsup for CTE \"%s\"", rte->ctename);
2571  }
2572  ctepath = cteroot->non_recursive_path;
2573  if (!ctepath) /* shouldn't happen */
2574  elog(ERROR, "could not find path for CTE \"%s\"", rte->ctename);
2575 
2576  /* Mark rel with estimated output rows, width, etc */
2577  set_cte_size_estimates(root, rel, ctepath->rows);
2578 
2579  /*
2580  * We don't support pushing join clauses into the quals of a worktable
2581  * scan, but it could still have required parameterization due to LATERAL
2582  * refs in its tlist. (I'm not sure this is actually possible given the
2583  * restrictions on recursive references, but it's easy enough to support.)
2584  */
2585  required_outer = rel->lateral_relids;
2586 
2587  /* Generate appropriate path */
2588  add_path(rel, create_worktablescan_path(root, rel, required_outer));
2589 }
2590 
2591 /*
2592  * generate_gather_paths
2593  * Generate parallel access paths for a relation by pushing a Gather or
2594  * Gather Merge on top of a partial path.
2595  *
2596  * This must not be called until after we're done creating all partial paths
2597  * for the specified relation. (Otherwise, add_partial_path might delete a
2598  * path that some GatherPath or GatherMergePath has a reference to.)
2599  *
2600  * If we're generating paths for a scan or join relation, override_rows will
2601  * be false, and we'll just use the relation's size estimate. When we're
2602  * being called for a partially-grouped path, though, we need to override
2603  * the rowcount estimate. (It's not clear that the particular value we're
2604  * using here is actually best, but the underlying rel has no estimate so
2605  * we must do something.)
2606  */
2607 void
2608 generate_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_rows)
2609 {
2610  Path *cheapest_partial_path;
2611  Path *simple_gather_path;
2612  ListCell *lc;
2613  double rows;
2614  double *rowsp = NULL;
2615 
2616  /* If there are no partial paths, there's nothing to do here. */
2617  if (rel->partial_pathlist == NIL)
2618  return;
2619 
2620  /* Should we override the rel's rowcount estimate? */
2621  if (override_rows)
2622  rowsp = &rows;
2623 
2624  /*
2625  * The output of Gather is always unsorted, so there's only one partial
2626  * path of interest: the cheapest one. That will be the one at the front
2627  * of partial_pathlist because of the way add_partial_path works.
2628  */
2629  cheapest_partial_path = linitial(rel->partial_pathlist);
2630  rows =
2631  cheapest_partial_path->rows * cheapest_partial_path->parallel_workers;
2632  simple_gather_path = (Path *)
2633  create_gather_path(root, rel, cheapest_partial_path, rel->reltarget,
2634  NULL, rowsp);
2635  add_path(rel, simple_gather_path);
2636 
2637  /*
2638  * For each useful ordering, we can consider an order-preserving Gather
2639  * Merge.
2640  */
2641  foreach(lc, rel->partial_pathlist)
2642  {
2643  Path *subpath = (Path *) lfirst(lc);
2644  GatherMergePath *path;
2645 
2646  if (subpath->pathkeys == NIL)
2647  continue;
2648 
2649  rows = subpath->rows * subpath->parallel_workers;
2650  path = create_gather_merge_path(root, rel, subpath, rel->reltarget,
2651  subpath->pathkeys, NULL, rowsp);
2652  add_path(rel, &path->path);
2653  }
2654 }
2655 
2656 /*
2657  * get_useful_pathkeys_for_relation
2658  * Determine which orderings of a relation might be useful.
2659  *
2660  * Getting data in sorted order can be useful either because the requested
2661  * order matches the final output ordering for the overall query we're
2662  * planning, or because it enables an efficient merge join. Here, we try
2663  * to figure out which pathkeys to consider.
2664  *
2665  * This allows us to do incremental sort on top of an index scan under a gather
2666  * merge node, i.e. parallelized.
2667  *
2668  * If the require_parallel_safe is true, we also require the expressions to
2669  * be parallel safe (which allows pushing the sort below Gather Merge).
2670  *
2671  * XXX At the moment this can only ever return a list with a single element,
2672  * because it looks at query_pathkeys only. So we might return the pathkeys
2673  * directly, but it seems plausible we'll want to consider other orderings
2674  * in the future. For example, we might want to consider pathkeys useful for
2675  * merge joins.
2676  */
2677 static List *
2679  bool require_parallel_safe)
2680 {
2681  List *useful_pathkeys_list = NIL;
2682 
2683  /*
2684  * Considering query_pathkeys is always worth it, because it might allow
2685  * us to avoid a total sort when we have a partially presorted path
2686  * available or to push the total sort into the parallel portion of the
2687  * query.
2688  */
2689  if (root->query_pathkeys)
2690  {
2691  ListCell *lc;
2692  int npathkeys = 0; /* useful pathkeys */
2693 
2694  foreach(lc, root->query_pathkeys)
2695  {
2696  PathKey *pathkey = (PathKey *) lfirst(lc);
2697  EquivalenceClass *pathkey_ec = pathkey->pk_eclass;
2698 
2699  /*
2700  * We can only build a sort for pathkeys that contain a
2701  * safe-to-compute-early EC member computable from the current
2702  * relation's reltarget, so ignore the remainder of the list as
2703  * soon as we find a pathkey without such a member.
2704  *
2705  * It's still worthwhile to return any prefix of the pathkeys list
2706  * that meets this requirement, as we may be able to do an
2707  * incremental sort.
2708  *
2709  * If requested, ensure the sort expression is parallel-safe too.
2710  */
2711  if (!relation_can_be_sorted_early(root, rel, pathkey_ec,
2712  require_parallel_safe))
2713  break;
2714 
2715  npathkeys++;
2716  }
2717 
2718  /*
2719  * The whole query_pathkeys list matches, so append it directly, to
2720  * allow comparing pathkeys easily by comparing list pointer. If we
2721  * have to truncate the pathkeys, we gotta do a copy though.
2722  */
2723  if (npathkeys == list_length(root->query_pathkeys))
2724  useful_pathkeys_list = lappend(useful_pathkeys_list,
2725  root->query_pathkeys);
2726  else if (npathkeys > 0)
2727  useful_pathkeys_list = lappend(useful_pathkeys_list,
2729  npathkeys));
2730  }
2731 
2732  return useful_pathkeys_list;
2733 }
2734 
2735 /*
2736  * generate_useful_gather_paths
2737  * Generate parallel access paths for a relation by pushing a Gather or
2738  * Gather Merge on top of a partial path.
2739  *
2740  * Unlike plain generate_gather_paths, this looks both at pathkeys of input
2741  * paths (aiming to preserve the ordering), but also considers ordering that
2742  * might be useful for nodes above the gather merge node, and tries to add
2743  * a sort (regular or incremental) to provide that.
2744  */
2745 void
2746 generate_useful_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_rows)
2747 {
2748  ListCell *lc;
2749  double rows;
2750  double *rowsp = NULL;
2751  List *useful_pathkeys_list = NIL;
2752  Path *cheapest_partial_path = NULL;
2753 
2754  /* If there are no partial paths, there's nothing to do here. */
2755  if (rel->partial_pathlist == NIL)
2756  return;
2757 
2758  /* Should we override the rel's rowcount estimate? */
2759  if (override_rows)
2760  rowsp = &rows;
2761 
2762  /* generate the regular gather (merge) paths */
2763  generate_gather_paths(root, rel, override_rows);
2764 
2765  /* consider incremental sort for interesting orderings */
2766  useful_pathkeys_list = get_useful_pathkeys_for_relation(root, rel, true);
2767 
2768  /* used for explicit (full) sort paths */
2769  cheapest_partial_path = linitial(rel->partial_pathlist);
2770 
2771  /*
2772  * Consider sorted paths for each interesting ordering. We generate both
2773  * incremental and full sort.
2774  */
2775  foreach(lc, useful_pathkeys_list)
2776  {
2777  List *useful_pathkeys = lfirst(lc);
2778  ListCell *lc2;
2779  bool is_sorted;
2780  int presorted_keys;
2781 
2782  foreach(lc2, rel->partial_pathlist)
2783  {
2784  Path *subpath = (Path *) lfirst(lc2);
2785  GatherMergePath *path;
2786 
2787  is_sorted = pathkeys_count_contained_in(useful_pathkeys,
2788  subpath->pathkeys,
2789  &presorted_keys);
2790 
2791  /*
2792  * We don't need to consider the case where a subpath is already
2793  * fully sorted because generate_gather_paths already creates a
2794  * gather merge path for every subpath that has pathkeys present.
2795  *
2796  * But since the subpath is already sorted, we know we don't need
2797  * to consider adding a sort (full or incremental) on top of it,
2798  * so we can continue here.
2799  */
2800  if (is_sorted)
2801  continue;
2802 
2803  /*
2804  * Consider regular sort for the cheapest partial path (for each
2805  * useful pathkeys). We know the path is not sorted, because we'd
2806  * not get here otherwise.
2807  *
2808  * This is not redundant with the gather paths created in
2809  * generate_gather_paths, because that doesn't generate ordered
2810  * output. Here we add an explicit sort to match the useful
2811  * ordering.
2812  */
2813  if (cheapest_partial_path == subpath)
2814  {
2815  Path *tmp;
2816 
2817  tmp = (Path *) create_sort_path(root,
2818  rel,
2819  subpath,
2820  useful_pathkeys,
2821  -1.0);
2822 
2823  rows = tmp->rows * tmp->parallel_workers;
2824 
2825  path = create_gather_merge_path(root, rel,
2826  tmp,
2827  rel->reltarget,
2828  tmp->pathkeys,
2829  NULL,
2830  rowsp);
2831 
2832  add_path(rel, &path->path);
2833 
2834  /* Fall through */
2835  }
2836 
2837  /*
2838  * Consider incremental sort, but only when the subpath is already
2839  * partially sorted on a pathkey prefix.
2840  */
2841  if (enable_incremental_sort && presorted_keys > 0)
2842  {
2843  Path *tmp;
2844 
2845  /*
2846  * We should have already excluded pathkeys of length 1
2847  * because then presorted_keys > 0 would imply is_sorted was
2848  * true.
2849  */
2850  Assert(list_length(useful_pathkeys) != 1);
2851 
2852  tmp = (Path *) create_incremental_sort_path(root,
2853  rel,
2854  subpath,
2855  useful_pathkeys,
2856  presorted_keys,
2857  -1);
2858 
2859  path = create_gather_merge_path(root, rel,
2860  tmp,
2861  rel->reltarget,
2862  tmp->pathkeys,
2863  NULL,
2864  rowsp);
2865 
2866  add_path(rel, &path->path);
2867  }
2868  }
2869  }
2870 }
2871 
2872 /*
2873  * make_rel_from_joinlist
2874  * Build access paths using a "joinlist" to guide the join path search.
2875  *
2876  * See comments for deconstruct_jointree() for definition of the joinlist
2877  * data structure.
2878  */
2879 static RelOptInfo *
2881 {
2882  int levels_needed;
2883  List *initial_rels;
2884  ListCell *jl;
2885 
2886  /*
2887  * Count the number of child joinlist nodes. This is the depth of the
2888  * dynamic-programming algorithm we must employ to consider all ways of
2889  * joining the child nodes.
2890  */
2891  levels_needed = list_length(joinlist);
2892 
2893  if (levels_needed <= 0)
2894  return NULL; /* nothing to do? */
2895 
2896  /*
2897  * Construct a list of rels corresponding to the child joinlist nodes.
2898  * This may contain both base rels and rels constructed according to
2899  * sub-joinlists.
2900  */
2901  initial_rels = NIL;
2902  foreach(jl, joinlist)
2903  {
2904  Node *jlnode = (Node *) lfirst(jl);
2905  RelOptInfo *thisrel;
2906 
2907  if (IsA(jlnode, RangeTblRef))
2908  {
2909  int varno = ((RangeTblRef *) jlnode)->rtindex;
2910 
2911  thisrel = find_base_rel(root, varno);
2912  }
2913  else if (IsA(jlnode, List))
2914  {
2915  /* Recurse to handle subproblem */
2916  thisrel = make_rel_from_joinlist(root, (List *) jlnode);
2917  }
2918  else
2919  {
2920  elog(ERROR, "unrecognized joinlist node type: %d",
2921  (int) nodeTag(jlnode));
2922  thisrel = NULL; /* keep compiler quiet */
2923  }
2924 
2925  initial_rels = lappend(initial_rels, thisrel);
2926  }
2927 
2928  if (levels_needed == 1)
2929  {
2930  /*
2931  * Single joinlist node, so we're done.
2932  */
2933  return (RelOptInfo *) linitial(initial_rels);
2934  }
2935  else
2936  {
2937  /*
2938  * Consider the different orders in which we could join the rels,
2939  * using a plugin, GEQO, or the regular join search code.
2940  *
2941  * We put the initial_rels list into a PlannerInfo field because
2942  * has_legal_joinclause() needs to look at it (ugly :-().
2943  */
2944  root->initial_rels = initial_rels;
2945 
2946  if (join_search_hook)
2947  return (*join_search_hook) (root, levels_needed, initial_rels);
2948  else if (enable_geqo && levels_needed >= geqo_threshold)
2949  return geqo(root, levels_needed, initial_rels);
2950  else
2951  return standard_join_search(root, levels_needed, initial_rels);
2952  }
2953 }
2954 
2955 /*
2956  * standard_join_search
2957  * Find possible joinpaths for a query by successively finding ways
2958  * to join component relations into join relations.
2959  *
2960  * 'levels_needed' is the number of iterations needed, ie, the number of
2961  * independent jointree items in the query. This is > 1.
2962  *
2963  * 'initial_rels' is a list of RelOptInfo nodes for each independent
2964  * jointree item. These are the components to be joined together.
2965  * Note that levels_needed == list_length(initial_rels).
2966  *
2967  * Returns the final level of join relations, i.e., the relation that is
2968  * the result of joining all the original relations together.
2969  * At least one implementation path must be provided for this relation and
2970  * all required sub-relations.
2971  *
2972  * To support loadable plugins that modify planner behavior by changing the
2973  * join searching algorithm, we provide a hook variable that lets a plugin
2974  * replace or supplement this function. Any such hook must return the same
2975  * final join relation as the standard code would, but it might have a
2976  * different set of implementation paths attached, and only the sub-joinrels
2977  * needed for these paths need have been instantiated.
2978  *
2979  * Note to plugin authors: the functions invoked during standard_join_search()
2980  * modify root->join_rel_list and root->join_rel_hash. If you want to do more
2981  * than one join-order search, you'll probably need to save and restore the
2982  * original states of those data structures. See geqo_eval() for an example.
2983  */
2984 RelOptInfo *
2985 standard_join_search(PlannerInfo *root, int levels_needed, List *initial_rels)
2986 {
2987  int lev;
2988  RelOptInfo *rel;
2989 
2990  /*
2991  * This function cannot be invoked recursively within any one planning
2992  * problem, so join_rel_level[] can't be in use already.
2993  */
2994  Assert(root->join_rel_level == NULL);
2995 
2996  /*
2997  * We employ a simple "dynamic programming" algorithm: we first find all
2998  * ways to build joins of two jointree items, then all ways to build joins
2999  * of three items (from two-item joins and single items), then four-item
3000  * joins, and so on until we have considered all ways to join all the
3001  * items into one rel.
3002  *
3003  * root->join_rel_level[j] is a list of all the j-item rels. Initially we
3004  * set root->join_rel_level[1] to represent all the single-jointree-item
3005  * relations.
3006  */
3007  root->join_rel_level = (List **) palloc0((levels_needed + 1) * sizeof(List *));
3008 
3009  root->join_rel_level[1] = initial_rels;
3010 
3011  for (lev = 2; lev <= levels_needed; lev++)
3012  {
3013  ListCell *lc;
3014 
3015  /*
3016  * Determine all possible pairs of relations to be joined at this
3017  * level, and build paths for making each one from every available
3018  * pair of lower-level relations.
3019  */
3020  join_search_one_level(root, lev);
3021 
3022  /*
3023  * Run generate_partitionwise_join_paths() and
3024  * generate_useful_gather_paths() for each just-processed joinrel. We
3025  * could not do this earlier because both regular and partial paths
3026  * can get added to a particular joinrel at multiple times within
3027  * join_search_one_level.
3028  *
3029  * After that, we're done creating paths for the joinrel, so run
3030  * set_cheapest().
3031  */
3032  foreach(lc, root->join_rel_level[lev])
3033  {
3034  rel = (RelOptInfo *) lfirst(lc);
3035 
3036  /* Create paths for partitionwise joins. */
3038 
3039  /*
3040  * Except for the topmost scan/join rel, consider gathering
3041  * partial paths. We'll do the same for the topmost scan/join rel
3042  * once we know the final targetlist (see grouping_planner).
3043  */
3044  if (lev < levels_needed)
3045  generate_useful_gather_paths(root, rel, false);
3046 
3047  /* Find and save the cheapest paths for this rel */
3048  set_cheapest(rel);
3049 
3050 #ifdef OPTIMIZER_DEBUG
3051  debug_print_rel(root, rel);
3052 #endif
3053  }
3054  }
3055 
3056  /*
3057  * We should have a single rel at the final level.
3058  */
3059  if (root->join_rel_level[levels_needed] == NIL)
3060  elog(ERROR, "failed to build any %d-way joins", levels_needed);
3061  Assert(list_length(root->join_rel_level[levels_needed]) == 1);
3062 
3063  rel = (RelOptInfo *) linitial(root->join_rel_level[levels_needed]);
3064 
3065  root->join_rel_level = NULL;
3066 
3067  return rel;
3068 }
3069 
3070 /*****************************************************************************
3071  * PUSHING QUALS DOWN INTO SUBQUERIES
3072  *****************************************************************************/
3073 
3074 /*
3075  * subquery_is_pushdown_safe - is a subquery safe for pushing down quals?
3076  *
3077  * subquery is the particular component query being checked. topquery
3078  * is the top component of a set-operations tree (the same Query if no
3079  * set-op is involved).
3080  *
3081  * Conditions checked here:
3082  *
3083  * 1. If the subquery has a LIMIT clause, we must not push down any quals,
3084  * since that could change the set of rows returned.
3085  *
3086  * 2. If the subquery contains EXCEPT or EXCEPT ALL set ops we cannot push
3087  * quals into it, because that could change the results.
3088  *
3089  * 3. If the subquery uses DISTINCT, we cannot push volatile quals into it.
3090  * This is because upper-level quals should semantically be evaluated only
3091  * once per distinct row, not once per original row, and if the qual is
3092  * volatile then extra evaluations could change the results. (This issue
3093  * does not apply to other forms of aggregation such as GROUP BY, because
3094  * when those are present we push into HAVING not WHERE, so that the quals
3095  * are still applied after aggregation.)
3096  *
3097  * 4. If the subquery contains window functions, we cannot push volatile quals
3098  * into it. The issue here is a bit different from DISTINCT: a volatile qual
3099  * might succeed for some rows of a window partition and fail for others,
3100  * thereby changing the partition contents and thus the window functions'
3101  * results for rows that remain.
3102  *
3103  * 5. If the subquery contains any set-returning functions in its targetlist,
3104  * we cannot push volatile quals into it. That would push them below the SRFs
3105  * and thereby change the number of times they are evaluated. Also, a
3106  * volatile qual could succeed for some SRF output rows and fail for others,
3107  * a behavior that cannot occur if it's evaluated before SRF expansion.
3108  *
3109  * 6. If the subquery has nonempty grouping sets, we cannot push down any
3110  * quals. The concern here is that a qual referencing a "constant" grouping
3111  * column could get constant-folded, which would be improper because the value
3112  * is potentially nullable by grouping-set expansion. This restriction could
3113  * be removed if we had a parsetree representation that shows that such
3114  * grouping columns are not really constant. (There are other ideas that
3115  * could be used to relax this restriction, but that's the approach most
3116  * likely to get taken in the future. Note that there's not much to be gained
3117  * so long as subquery_planner can't move HAVING clauses to WHERE within such
3118  * a subquery.)
3119  *
3120  * In addition, we make several checks on the subquery's output columns to see
3121  * if it is safe to reference them in pushed-down quals. If output column k
3122  * is found to be unsafe to reference, we set safetyInfo->unsafeColumns[k]
3123  * to true, but we don't reject the subquery overall since column k might not
3124  * be referenced by some/all quals. The unsafeColumns[] array will be
3125  * consulted later by qual_is_pushdown_safe(). It's better to do it this way
3126  * than to make the checks directly in qual_is_pushdown_safe(), because when
3127  * the subquery involves set operations we have to check the output
3128  * expressions in each arm of the set op.
3129  *
3130  * Note: pushing quals into a DISTINCT subquery is theoretically dubious:
3131  * we're effectively assuming that the quals cannot distinguish values that
3132  * the DISTINCT's equality operator sees as equal, yet there are many
3133  * counterexamples to that assumption. However use of such a qual with a
3134  * DISTINCT subquery would be unsafe anyway, since there's no guarantee which
3135  * "equal" value will be chosen as the output value by the DISTINCT operation.
3136  * So we don't worry too much about that. Another objection is that if the
3137  * qual is expensive to evaluate, running it for each original row might cost
3138  * more than we save by eliminating rows before the DISTINCT step. But it
3139  * would be very hard to estimate that at this stage, and in practice pushdown
3140  * seldom seems to make things worse, so we ignore that problem too.
3141  *
3142  * Note: likewise, pushing quals into a subquery with window functions is a
3143  * bit dubious: the quals might remove some rows of a window partition while
3144  * leaving others, causing changes in the window functions' results for the
3145  * surviving rows. We insist that such a qual reference only partitioning
3146  * columns, but again that only protects us if the qual does not distinguish
3147  * values that the partitioning equality operator sees as equal. The risks
3148  * here are perhaps larger than for DISTINCT, since no de-duplication of rows
3149  * occurs and thus there is no theoretical problem with such a qual. But
3150  * we'll do this anyway because the potential performance benefits are very
3151  * large, and we've seen no field complaints about the longstanding comparable
3152  * behavior with DISTINCT.
3153  */
3154 static bool
3156  pushdown_safety_info *safetyInfo)
3157 {
3158  SetOperationStmt *topop;
3159 
3160  /* Check point 1 */
3161  if (subquery->limitOffset != NULL || subquery->limitCount != NULL)
3162  return false;
3163 
3164  /* Check point 6 */
3165  if (subquery->groupClause && subquery->groupingSets)
3166  return false;
3167 
3168  /* Check points 3, 4, and 5 */
3169  if (subquery->distinctClause ||
3170  subquery->hasWindowFuncs ||
3171  subquery->hasTargetSRFs)
3172  safetyInfo->unsafeVolatile = true;
3173 
3174  /*
3175  * If we're at a leaf query, check for unsafe expressions in its target
3176  * list, and mark any unsafe ones in unsafeColumns[]. (Non-leaf nodes in
3177  * setop trees have only simple Vars in their tlists, so no need to check
3178  * them.)
3179  */
3180  if (subquery->setOperations == NULL)
3181  check_output_expressions(subquery, safetyInfo);
3182 
3183  /* Are we at top level, or looking at a setop component? */
3184  if (subquery == topquery)
3185  {
3186  /* Top level, so check any component queries */
3187  if (subquery->setOperations != NULL)
3188  if (!recurse_pushdown_safe(subquery->setOperations, topquery,
3189  safetyInfo))
3190  return false;
3191  }
3192  else
3193  {
3194  /* Setop component must not have more components (too weird) */
3195  if (subquery->setOperations != NULL)
3196  return false;
3197  /* Check whether setop component output types match top level */
3198  topop = castNode(SetOperationStmt, topquery->setOperations);
3199  Assert(topop);
3201  topop->colTypes,
3202  safetyInfo);
3203  }
3204  return true;
3205 }
3206 
3207 /*
3208  * Helper routine to recurse through setOperations tree
3209  */
3210 static bool
3212  pushdown_safety_info *safetyInfo)
3213 {
3214  if (IsA(setOp, RangeTblRef))
3215  {
3216  RangeTblRef *rtr = (RangeTblRef *) setOp;
3217  RangeTblEntry *rte = rt_fetch(rtr->rtindex, topquery->rtable);
3218  Query *subquery = rte->subquery;
3219 
3220  Assert(subquery != NULL);
3221  return subquery_is_pushdown_safe(subquery, topquery, safetyInfo);
3222  }
3223  else if (IsA(setOp, SetOperationStmt))
3224  {
3225  SetOperationStmt *op = (SetOperationStmt *) setOp;
3226 
3227  /* EXCEPT is no good (point 2 for subquery_is_pushdown_safe) */
3228  if (op->op == SETOP_EXCEPT)
3229  return false;
3230  /* Else recurse */
3231  if (!recurse_pushdown_safe(op->larg, topquery, safetyInfo))
3232  return false;
3233  if (!recurse_pushdown_safe(op->rarg, topquery, safetyInfo))
3234  return false;
3235  }
3236  else
3237  {
3238  elog(ERROR, "unrecognized node type: %d",
3239  (int) nodeTag(setOp));
3240  }
3241  return true;
3242 }
3243 
3244 /*
3245  * check_output_expressions - check subquery's output expressions for safety
3246  *
3247  * There are several cases in which it's unsafe to push down an upper-level
3248  * qual if it references a particular output column of a subquery. We check
3249  * each output column of the subquery and set unsafeColumns[k] to true if
3250  * that column is unsafe for a pushed-down qual to reference. The conditions
3251  * checked here are:
3252  *
3253  * 1. We must not push down any quals that refer to subselect outputs that
3254  * return sets, else we'd introduce functions-returning-sets into the
3255  * subquery's WHERE/HAVING quals.
3256  *
3257  * 2. We must not push down any quals that refer to subselect outputs that
3258  * contain volatile functions, for fear of introducing strange results due
3259  * to multiple evaluation of a volatile function.
3260  *
3261  * 3. If the subquery uses DISTINCT ON, we must not push down any quals that
3262  * refer to non-DISTINCT output columns, because that could change the set
3263  * of rows returned. (This condition is vacuous for DISTINCT, because then
3264  * there are no non-DISTINCT output columns, so we needn't check. Note that
3265  * subquery_is_pushdown_safe already reported that we can't use volatile
3266  * quals if there's DISTINCT or DISTINCT ON.)
3267  *
3268  * 4. If the subquery has any window functions, we must not push down quals
3269  * that reference any output columns that are not listed in all the subquery's
3270  * window PARTITION BY clauses. We can push down quals that use only
3271  * partitioning columns because they should succeed or fail identically for
3272  * every row of any one window partition, and totally excluding some
3273  * partitions will not change a window function's results for remaining
3274  * partitions. (Again, this also requires nonvolatile quals, but
3275  * subquery_is_pushdown_safe handles that.)
3276  */
3277 static void
3279 {
3280  ListCell *lc;
3281 
3282  foreach(lc, subquery->targetList)
3283  {
3284  TargetEntry *tle = (TargetEntry *) lfirst(lc);
3285 
3286  if (tle->resjunk)
3287  continue; /* ignore resjunk columns */
3288 
3289  /* We need not check further if output col is already known unsafe */
3290  if (safetyInfo->unsafeColumns[tle->resno])
3291  continue;
3292 
3293  /* Functions returning sets are unsafe (point 1) */
3294  if (subquery->hasTargetSRFs &&
3295  expression_returns_set((Node *) tle->expr))
3296  {
3297  safetyInfo->unsafeColumns[tle->resno] = true;
3298  continue;
3299  }
3300 
3301  /* Volatile functions are unsafe (point 2) */
3302  if (contain_volatile_functions((Node *) tle->expr))
3303  {
3304  safetyInfo->unsafeColumns[tle->resno] = true;
3305  continue;
3306  }
3307 
3308  /* If subquery uses DISTINCT ON, check point 3 */
3309  if (subquery->hasDistinctOn &&
3310  !targetIsInSortList(tle, InvalidOid, subquery->distinctClause))
3311  {
3312  /* non-DISTINCT column, so mark it unsafe */
3313  safetyInfo->unsafeColumns[tle->resno] = true;
3314  continue;
3315  }
3316 
3317  /* If subquery uses window functions, check point 4 */
3318  if (subquery->hasWindowFuncs &&
3319  !targetIsInAllPartitionLists(tle, subquery))
3320  {
3321  /* not present in all PARTITION BY clauses, so mark it unsafe */
3322  safetyInfo->unsafeColumns[tle->resno] = true;
3323  continue;
3324  }
3325  }
3326 }
3327 
3328 /*
3329  * For subqueries using UNION/UNION ALL/INTERSECT/INTERSECT ALL, we can
3330  * push quals into each component query, but the quals can only reference
3331  * subquery columns that suffer no type coercions in the set operation.
3332  * Otherwise there are possible semantic gotchas. So, we check the
3333  * component queries to see if any of them have output types different from
3334  * the top-level setop outputs. unsafeColumns[k] is set true if column k
3335  * has different type in any component.
3336  *
3337  * We don't have to care about typmods here: the only allowed difference
3338  * between set-op input and output typmods is input is a specific typmod
3339  * and output is -1, and that does not require a coercion.
3340  *
3341  * tlist is a subquery tlist.
3342  * colTypes is an OID list of the top-level setop's output column types.
3343  * safetyInfo->unsafeColumns[] is the result array.
3344  */
3345 static void
3347  pushdown_safety_info *safetyInfo)
3348 {
3349  ListCell *l;
3350  ListCell *colType = list_head(colTypes);
3351 
3352  foreach(l, tlist)
3353  {
3354  TargetEntry *tle = (TargetEntry *) lfirst(l);
3355 
3356  if (tle->resjunk)
3357  continue; /* ignore resjunk columns */
3358  if (colType == NULL)
3359  elog(ERROR, "wrong number of tlist entries");
3360  if (exprType((Node *) tle->expr) != lfirst_oid(colType))
3361  safetyInfo->unsafeColumns[tle->resno] = true;
3362  colType = lnext(colTypes, colType);
3363  }
3364  if (colType != NULL)
3365  elog(ERROR, "wrong number of tlist entries");
3366 }
3367 
3368 /*
3369  * targetIsInAllPartitionLists
3370  * True if the TargetEntry is listed in the PARTITION BY clause
3371  * of every window defined in the query.
3372  *
3373  * It would be safe to ignore windows not actually used by any window
3374  * function, but it's not easy to get that info at this stage; and it's
3375  * unlikely to be useful to spend any extra cycles getting it, since
3376  * unreferenced window definitions are probably infrequent in practice.
3377  */
3378 static bool
3380 {
3381  ListCell *lc;
3382 
3383  foreach(lc, query->windowClause)
3384  {
3385  WindowClause *wc = (WindowClause *) lfirst(lc);
3386 
3388  return false;
3389  }
3390  return true;
3391 }
3392 
3393 /*
3394  * qual_is_pushdown_safe - is a particular rinfo safe to push down?
3395  *
3396  * rinfo is a restriction clause applying to the given subquery (whose RTE
3397  * has index rti in the parent query).
3398  *
3399  * Conditions checked here:
3400  *
3401  * 1. rinfo's clause must not contain any SubPlans (mainly because it's
3402  * unclear that it will work correctly: SubLinks will already have been
3403  * transformed into SubPlans in the qual, but not in the subquery). Note that
3404  * SubLinks that transform to initplans are safe, and will be accepted here
3405  * because what we'll see in the qual is just a Param referencing the initplan
3406  * output.
3407  *
3408  * 2. If unsafeVolatile is set, rinfo's clause must not contain any volatile
3409  * functions.
3410  *
3411  * 3. If unsafeLeaky is set, rinfo's clause must not contain any leaky
3412  * functions that are passed Var nodes, and therefore might reveal values from
3413  * the subquery as side effects.
3414  *
3415  * 4. rinfo's clause must not refer to the whole-row output of the subquery
3416  * (since there is no easy way to name that within the subquery itself).
3417  *
3418  * 5. rinfo's clause must not refer to any subquery output columns that were
3419  * found to be unsafe to reference by subquery_is_pushdown_safe().
3420  */
3421 static bool
3423  pushdown_safety_info *safetyInfo)
3424 {
3425  bool safe = true;
3426  Node *qual = (Node *) rinfo->clause;
3427  List *vars;
3428  ListCell *vl;
3429 
3430  /* Refuse subselects (point 1) */
3431  if (contain_subplans(qual))
3432  return false;
3433 
3434  /* Refuse volatile quals if we found they'd be unsafe (point 2) */
3435  if (safetyInfo->unsafeVolatile &&
3436  contain_volatile_functions((Node *) rinfo))
3437  return false;
3438 
3439  /* Refuse leaky quals if told to (point 3) */
3440  if (safetyInfo->unsafeLeaky &&
3441  contain_leaked_vars(qual))
3442  return false;
3443 
3444  /*
3445  * It would be unsafe to push down window function calls, but at least for
3446  * the moment we could never see any in a qual anyhow. (The same applies
3447  * to aggregates, which we check for in pull_var_clause below.)
3448  */
3450 
3451  /*
3452  * Examine all Vars used in clause. Since it's a restriction clause, all
3453  * such Vars must refer to subselect output columns ... unless this is
3454  * part of a LATERAL subquery, in which case there could be lateral
3455  * references.
3456  */
3458  foreach(vl, vars)
3459  {
3460  Var *var = (Var *) lfirst(vl);
3461 
3462  /*
3463  * XXX Punt if we find any PlaceHolderVars in the restriction clause.
3464  * It's not clear whether a PHV could safely be pushed down, and even
3465  * less clear whether such a situation could arise in any cases of
3466  * practical interest anyway. So for the moment, just refuse to push
3467  * down.
3468  */
3469  if (!IsA(var, Var))
3470  {
3471  safe = false;
3472  break;
3473  }
3474 
3475  /*
3476  * Punt if we find any lateral references. It would be safe to push
3477  * these down, but we'd have to convert them into outer references,
3478  * which subquery_push_qual lacks the infrastructure to do. The case
3479  * arises so seldom that it doesn't seem worth working hard on.
3480  */
3481  if (var->varno != rti)
3482  {
3483  safe = false;
3484  break;
3485  }
3486 
3487  /* Subqueries have no system columns */
3488  Assert(var->varattno >= 0);
3489 
3490  /* Check point 4 */
3491  if (var->varattno == 0)
3492  {
3493  safe = false;
3494  break;
3495  }
3496 
3497  /* Check point 5 */
3498  if (safetyInfo->unsafeColumns[var->varattno])
3499  {
3500  safe = false;
3501  break;
3502  }
3503  }
3504 
3505  list_free(vars);
3506 
3507  return safe;
3508 }
3509 
3510 /*
3511  * subquery_push_qual - push down a qual that we have determined is safe
3512  */
3513 static void
3514 subquery_push_qual(Query *subquery, RangeTblEntry *rte, Index rti, Node *qual)
3515 {
3516  if (subquery->setOperations != NULL)
3517  {
3518  /* Recurse to push it separately to each component query */
3519  recurse_push_qual(subquery->setOperations, subquery,
3520  rte, rti, qual);
3521  }
3522  else
3523  {
3524  /*
3525  * We need to replace Vars in the qual (which must refer to outputs of
3526  * the subquery) with copies of the subquery's targetlist expressions.
3527  * Note that at this point, any uplevel Vars in the qual should have
3528  * been replaced with Params, so they need no work.
3529  *
3530  * This step also ensures that when we are pushing into a setop tree,
3531  * each component query gets its own copy of the qual.
3532  */
3533  qual = ReplaceVarsFromTargetList(qual, rti, 0, rte,
3534  subquery->targetList,
3536  &subquery->hasSubLinks);
3537 
3538  /*
3539  * Now attach the qual to the proper place: normally WHERE, but if the
3540  * subquery uses grouping or aggregation, put it in HAVING (since the
3541  * qual really refers to the group-result rows).
3542  */
3543  if (subquery->hasAggs || subquery->groupClause || subquery->groupingSets || subquery->havingQual)
3544  subquery->havingQual = make_and_qual(subquery->havingQual, qual);
3545  else
3546  subquery->jointree->quals =
3547  make_and_qual(subquery->jointree->quals, qual);
3548 
3549  /*
3550  * We need not change the subquery's hasAggs or hasSubLinks flags,
3551  * since we can't be pushing down any aggregates that weren't there
3552  * before, and we don't push down subselects at all.
3553  */
3554  }
3555 }
3556 
3557 /*
3558  * Helper routine to recurse through setOperations tree
3559  */
3560 static void
3561 recurse_push_qual(Node *setOp, Query *topquery,
3562  RangeTblEntry *rte, Index rti, Node *qual)
3563 {
3564  if (IsA(setOp, RangeTblRef))
3565  {
3566  RangeTblRef *rtr = (RangeTblRef *) setOp;
3567  RangeTblEntry *subrte = rt_fetch(rtr->rtindex, topquery->rtable);
3568  Query *subquery = subrte->subquery;
3569 
3570  Assert(subquery != NULL);
3571  subquery_push_qual(subquery, rte, rti, qual);
3572  }
3573  else if (IsA(setOp, SetOperationStmt))
3574  {
3575  SetOperationStmt *op = (SetOperationStmt *) setOp;
3576 
3577  recurse_push_qual(op->larg, topquery, rte, rti, qual);
3578  recurse_push_qual(op->rarg, topquery, rte, rti, qual);
3579  }
3580  else
3581  {
3582  elog(ERROR, "unrecognized node type: %d",
3583  (int) nodeTag(setOp));
3584  }
3585 }
3586 
3587 /*****************************************************************************
3588  * SIMPLIFYING SUBQUERY TARGETLISTS
3589  *****************************************************************************/
3590 
3591 /*
3592  * remove_unused_subquery_outputs
3593  * Remove subquery targetlist items we don't need
3594  *
3595  * It's possible, even likely, that the upper query does not read all the
3596  * output columns of the subquery. We can remove any such outputs that are
3597  * not needed by the subquery itself (e.g., as sort/group columns) and do not
3598  * affect semantics otherwise (e.g., volatile functions can't be removed).
3599  * This is useful not only because we might be able to remove expensive-to-
3600  * compute expressions, but because deletion of output columns might allow
3601  * optimizations such as join removal to occur within the subquery.
3602  *
3603  * To avoid affecting column numbering in the targetlist, we don't physically
3604  * remove unused tlist entries, but rather replace their expressions with NULL
3605  * constants. This is implemented by modifying subquery->targetList.
3606  */
3607 static void
3609 {
3610  Bitmapset *attrs_used = NULL;
3611  ListCell *lc;
3612 
3613  /*
3614  * Do nothing if subquery has UNION/INTERSECT/EXCEPT: in principle we
3615  * could update all the child SELECTs' tlists, but it seems not worth the
3616  * trouble presently.
3617  */
3618  if (subquery->setOperations)
3619  return;
3620 
3621  /*
3622  * If subquery has regular DISTINCT (not DISTINCT ON), we're wasting our
3623  * time: all its output columns must be used in the distinctClause.
3624  */
3625  if (subquery->distinctClause && !subquery->hasDistinctOn)
3626  return;
3627 
3628  /*
3629  * Collect a bitmap of all the output column numbers used by the upper
3630  * query.
3631  *
3632  * Add all the attributes needed for joins or final output. Note: we must
3633  * look at rel's targetlist, not the attr_needed data, because attr_needed
3634  * isn't computed for inheritance child rels, cf set_append_rel_size().
3635  * (XXX might be worth changing that sometime.)
3636  */
3637  pull_varattnos((Node *) rel->reltarget->exprs, rel->relid, &attrs_used);
3638 
3639  /* Add all the attributes used by un-pushed-down restriction clauses. */
3640  foreach(lc, rel->baserestrictinfo)
3641  {
3642  RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
3643 
3644  pull_varattnos((Node *) rinfo->clause, rel->relid, &attrs_used);
3645  }
3646 
3647  /*
3648  * If there's a whole-row reference to the subquery, we can't remove
3649  * anything.
3650  */
3652  return;
3653 
3654  /*
3655  * Run through the tlist and zap entries we don't need. It's okay to
3656  * modify the tlist items in-place because set_subquery_pathlist made a
3657  * copy of the subquery.
3658  */
3659  foreach(lc, subquery->targetList)
3660  {
3661  TargetEntry *tle = (TargetEntry *) lfirst(lc);
3662  Node *texpr = (Node *) tle->expr;
3663 
3664  /*
3665  * If it has a sortgroupref number, it's used in some sort/group
3666  * clause so we'd better not remove it. Also, don't remove any
3667  * resjunk columns, since their reason for being has nothing to do
3668  * with anybody reading the subquery's output. (It's likely that
3669  * resjunk columns in a sub-SELECT would always have ressortgroupref
3670  * set, but even if they don't, it seems imprudent to remove them.)
3671  */
3672  if (tle->ressortgroupref || tle->resjunk)
3673  continue;
3674 
3675  /*
3676  * If it's used by the upper query, we can't remove it.
3677  */
3679  attrs_used))
3680  continue;
3681 
3682  /*
3683  * If it contains a set-returning function, we can't remove it since
3684  * that could change the number of rows returned by the subquery.
3685  */
3686  if (subquery->hasTargetSRFs &&
3687  expression_returns_set(texpr))
3688  continue;
3689 
3690  /*
3691  * If it contains volatile functions, we daren't remove it for fear
3692  * that the user is expecting their side-effects to happen.
3693  */
3694  if (contain_volatile_functions(texpr))
3695  continue;
3696 
3697  /*
3698  * OK, we don't need it. Replace the expression with a NULL constant.
3699  * Preserve the exposed type of the expression, in case something
3700  * looks at the rowtype of the subquery's result.
3701  */
3702  tle->expr = (Expr *) makeNullConst(exprType(texpr),
3703  exprTypmod(texpr),
3704  exprCollation(texpr));
3705  }
3706 }
3707 
3708 /*
3709  * create_partial_bitmap_paths
3710  * Build partial bitmap heap path for the relation
3711  */
3712 void
3714  Path *bitmapqual)
3715 {
3716  int parallel_workers;
3717  double pages_fetched;
3718 
3719  /* Compute heap pages for bitmap heap scan */
3720  pages_fetched = compute_bitmap_pages(root, rel, bitmapqual, 1.0,
3721  NULL, NULL);
3722 
3723  parallel_workers = compute_parallel_worker(rel, pages_fetched, -1,
3725 
3726  if (parallel_workers <= 0)
3727  return;
3728 
3729  add_partial_path(rel, (Path *) create_bitmap_heap_path(root, rel,
3730  bitmapqual, rel->lateral_relids, 1.0, parallel_workers));
3731 }
3732 
3733 /*
3734  * Compute the number of parallel workers that should be used to scan a
3735  * relation. We compute the parallel workers based on the size of the heap to
3736  * be scanned and the size of the index to be scanned, then choose a minimum
3737  * of those.
3738  *
3739  * "heap_pages" is the number of pages from the table that we expect to scan, or
3740  * -1 if we don't expect to scan any.
3741  *
3742  * "index_pages" is the number of pages from the index that we expect to scan, or
3743  * -1 if we don't expect to scan any.
3744  *
3745  * "max_workers" is caller's limit on the number of workers. This typically
3746  * comes from a GUC.
3747  */
3748 int
3749 compute_parallel_worker(RelOptInfo *rel, double heap_pages, double index_pages,
3750  int max_workers)
3751 {
3752  int parallel_workers = 0;
3753 
3754  /*
3755  * If the user has set the parallel_workers reloption, use that; otherwise
3756  * select a default number of workers.
3757  */
3758  if (rel->rel_parallel_workers != -1)
3759  parallel_workers = rel->rel_parallel_workers;
3760  else
3761  {
3762  /*
3763  * If the number of pages being scanned is insufficient to justify a
3764  * parallel scan, just return zero ... unless it's an inheritance
3765  * child. In that case, we want to generate a parallel path here
3766  * anyway. It might not be worthwhile just for this relation, but
3767  * when combined with all of its inheritance siblings it may well pay
3768  * off.
3769  */
3770  if (rel->reloptkind == RELOPT_BASEREL &&
3771  ((heap_pages >= 0 && heap_pages < min_parallel_table_scan_size) ||
3772  (index_pages >= 0 && index_pages < min_parallel_index_scan_size)))
3773  return 0;
3774 
3775  if (heap_pages >= 0)
3776  {
3777  int heap_parallel_threshold;
3778  int heap_parallel_workers = 1;
3779 
3780  /*
3781  * Select the number of workers based on the log of the size of
3782  * the relation. This probably needs to be a good deal more
3783  * sophisticated, but we need something here for now. Note that
3784  * the upper limit of the min_parallel_table_scan_size GUC is
3785  * chosen to prevent overflow here.
3786  */
3787  heap_parallel_threshold = Max(min_parallel_table_scan_size, 1);
3788  while (heap_pages >= (BlockNumber) (heap_parallel_threshold * 3))
3789  {
3790  heap_parallel_workers++;
3791  heap_parallel_threshold *= 3;
3792  if (heap_parallel_threshold > INT_MAX / 3)
3793  break; /* avoid overflow */
3794  }
3795 
3796  parallel_workers = heap_parallel_workers;
3797  }
3798 
3799  if (index_pages >= 0)
3800  {
3801  int index_parallel_workers = 1;
3802  int index_parallel_threshold;
3803 
3804  /* same calculation as for heap_pages above */
3805  index_parallel_threshold = Max(min_parallel_index_scan_size, 1);
3806  while (index_pages >= (BlockNumber) (index_parallel_threshold * 3))
3807  {
3808  index_parallel_workers++;
3809  index_parallel_threshold *= 3;
3810  if (index_parallel_threshold > INT_MAX / 3)
3811  break; /* avoid overflow */
3812  }
3813 
3814  if (parallel_workers > 0)
3815  parallel_workers = Min(parallel_workers, index_parallel_workers);
3816  else
3817  parallel_workers = index_parallel_workers;
3818  }
3819  }
3820 
3821  /* In no case use more than caller supplied maximum number of workers */
3822  parallel_workers = Min(parallel_workers, max_workers);
3823 
3824  return parallel_workers;
3825 }
3826 
3827 /*
3828  * generate_partitionwise_join_paths
3829  * Create paths representing partitionwise join for given partitioned
3830  * join relation.
3831  *
3832  * This must not be called until after we are done adding paths for all
3833  * child-joins. Otherwise, add_path might delete a path to which some path
3834  * generated here has a reference.
3835  */
3836 void
3838 {
3839  List *live_children = NIL;
3840  int cnt_parts;
3841  int num_parts;
3842  RelOptInfo **part_rels;
3843 
3844  /* Handle only join relations here. */
3845  if (!IS_JOIN_REL(rel))
3846  return;
3847 
3848  /* We've nothing to do if the relation is not partitioned. */
3849  if (!IS_PARTITIONED_REL(rel))
3850  return;
3851 
3852  /* The relation should have consider_partitionwise_join set. */
3854 
3855  /* Guard against stack overflow due to overly deep partition hierarchy. */
3857 
3858  num_parts = rel->nparts;
3859  part_rels = rel->part_rels;
3860 
3861  /* Collect non-dummy child-joins. */
3862  for (cnt_parts = 0; cnt_parts < num_parts; cnt_parts++)
3863  {
3864  RelOptInfo *child_rel = part_rels[cnt_parts];
3865 
3866  /* If it's been pruned entirely, it's certainly dummy. */
3867  if (child_rel == NULL)
3868  continue;
3869 
3870  /* Add partitionwise join paths for partitioned child-joins. */
3871  generate_partitionwise_join_paths(root, child_rel);
3872 
3873  set_cheapest(child_rel);
3874 
3875  /* Dummy children will not be scanned, so ignore those. */
3876  if (IS_DUMMY_REL(child_rel))
3877  continue;
3878 
3879 #ifdef OPTIMIZER_DEBUG
3880  debug_print_rel(root, child_rel);
3881 #endif
3882 
3883  live_children = lappend(live_children, child_rel);
3884  }
3885 
3886  /* If all child-joins are dummy, parent join is also dummy. */
3887  if (!live_children)
3888  {
3889  mark_dummy_rel(rel);
3890  return;
3891  }
3892 
3893  /* Build additional paths for this rel from child-join paths. */
3894  add_paths_to_append_rel(root, rel, live_children);
3895  list_free(live_children);
3896 }
3897 
3898 
3899 /*****************************************************************************
3900  * DEBUG SUPPORT
3901  *****************************************************************************/
3902 
3903 #ifdef OPTIMIZER_DEBUG
3904 
3905 static void
3906 print_relids(PlannerInfo *root, Relids relids)
3907 {
3908  int x;
3909  bool first = true;
3910 
3911  x = -1;
3912  while ((x = bms_next_member(relids, x)) >= 0)
3913  {
3914  if (!first)
3915  printf(" ");
3916  if (x < root->simple_rel_array_size &&
3917  root->simple_rte_array[x])
3918  printf("%s", root->simple_rte_array[x]->eref->aliasname);
3919  else
3920  printf("%d", x);
3921  first = false;
3922  }
3923 }
3924 
3925 static void
3926 print_restrictclauses(PlannerInfo *root, List *clauses)
3927 {
3928  ListCell *l;
3929 
3930  foreach(l, clauses)
3931  {
3932  RestrictInfo *c = lfirst(l);
3933 
3934  print_expr((Node *) c->clause, root->parse->rtable);
3935  if (lnext(clauses, l))
3936  printf(", ");
3937  }
3938 }
3939 
3940 static void
3941 print_path(PlannerInfo *root, Path *path, int indent)
3942 {
3943  const char *ptype;
3944  bool join = false;
3945  Path *subpath = NULL;
3946  int i;
3947 
3948  switch (nodeTag(path))
3949  {
3950  case T_Path:
3951  switch (path->pathtype)
3952  {
3953  case T_SeqScan:
3954  ptype = "SeqScan";
3955  break;
3956  case T_SampleScan:
3957  ptype = "SampleScan";
3958  break;
3959  case T_FunctionScan:
3960  ptype = "FunctionScan";
3961  break;
3962  case T_TableFuncScan:
3963  ptype = "TableFuncScan";
3964  break;
3965  case T_ValuesScan:
3966  ptype = "ValuesScan";
3967  break;
3968  case T_CteScan:
3969  ptype = "CteScan";
3970  break;
3971  case T_NamedTuplestoreScan:
3972  ptype = "NamedTuplestoreScan";
3973  break;
3974  case T_Result:
3975  ptype = "Result";
3976  break;
3977  case T_WorkTableScan:
3978  ptype = "WorkTableScan";
3979  break;
3980  default:
3981  ptype = "???Path";
3982  break;
3983  }
3984  break;
3985  case T_IndexPath:
3986  ptype = "IdxScan";
3987  break;
3988  case T_BitmapHeapPath:
3989  ptype = "BitmapHeapScan";
3990  break;
3991  case T_BitmapAndPath:
3992  ptype = "BitmapAndPath";
3993  break;
3994  case T_BitmapOrPath:
3995  ptype = "BitmapOrPath";
3996  break;
3997  case T_TidPath:
3998  ptype = "TidScan";
3999  break;
4000  case T_SubqueryScanPath:
4001  ptype = "SubqueryScan";
4002  break;
4003  case T_ForeignPath:
4004  ptype = "ForeignScan";
4005  break;
4006  case T_CustomPath:
4007  ptype = "CustomScan";
4008  break;
4009  case T_NestPath:
4010  ptype = "NestLoop";
4011  join = true;
4012  break;
4013  case T_MergePath:
4014  ptype = "MergeJoin";
4015  join = true;
4016  break;
4017  case T_HashPath:
4018  ptype = "HashJoin";
4019  join = true;
4020  break;
4021  case T_AppendPath:
4022  ptype = "Append";
4023  break;
4024  case T_MergeAppendPath:
4025  ptype = "MergeAppend";
4026  break;
4027  case T_GroupResultPath:
4028  ptype = "GroupResult";
4029  break;
4030  case T_MaterialPath:
4031  ptype = "Material";
4032  subpath = ((MaterialPath *) path)->subpath;
4033  break;
4034  case T_MemoizePath:
4035  ptype = "Memoize";
4036  subpath = ((MemoizePath *) path)->subpath;
4037  break;
4038  case T_UniquePath:
4039  ptype = "Unique";
4040  subpath = ((UniquePath *) path)->subpath;
4041  break;
4042  case T_GatherPath:
4043  ptype = "Gather";
4044  subpath = ((GatherPath *) path)->subpath;
4045  break;
4046  case T_GatherMergePath:
4047  ptype = "GatherMerge";
4048  subpath = ((GatherMergePath *) path)->subpath;
4049  break;
4050  case T_ProjectionPath:
4051  ptype = "Projection";
4052  subpath = ((ProjectionPath *) path)->subpath;
4053  break;
4054  case T_ProjectSetPath:
4055  ptype = "ProjectSet";
4056  subpath = ((ProjectSetPath *) path)->subpath;
4057  break;
4058  case T_SortPath:
4059  ptype = "Sort";
4060  subpath = ((SortPath *) path)->subpath;
4061  break;
4062  case T_IncrementalSortPath:
4063  ptype = "IncrementalSort";
4064  subpath = ((SortPath *) path)->subpath;
4065  break;
4066  case T_GroupPath:
4067  ptype = "Group";
4068  subpath = ((GroupPath *) path)->subpath;
4069  break;
4070  case T_UpperUniquePath:
4071  ptype = "UpperUnique";
4072  subpath = ((UpperUniquePath *) path)->subpath;
4073  break;
4074  case T_AggPath:
4075  ptype = "Agg";
4076  subpath = ((AggPath *) path)->subpath;
4077  break;
4078  case T_GroupingSetsPath:
4079  ptype = "GroupingSets";
4080  subpath = ((GroupingSetsPath *) path)->subpath;
4081  break;
4082  case T_MinMaxAggPath:
4083  ptype = "MinMaxAgg";
4084  break;
4085  case T_WindowAggPath:
4086  ptype = "WindowAgg";
4087  subpath = ((WindowAggPath *) path)->subpath;
4088  break;
4089  case T_SetOpPath:
4090  ptype = "SetOp";
4091  subpath = ((SetOpPath *) path)->subpath;
4092  break;
4093  case T_RecursiveUnionPath:
4094  ptype = "RecursiveUnion";
4095  break;
4096  case T_LockRowsPath:
4097  ptype = "LockRows";
4098  subpath = ((LockRowsPath *) path)->subpath;
4099  break;
4100  case T_ModifyTablePath:
4101  ptype = "ModifyTable";
4102  break;
4103  case T_LimitPath:
4104  ptype = "Limit";
4105  subpath = ((LimitPath *) path)->subpath;
4106  break;
4107  default:
4108  ptype = "???Path";
4109  break;
4110  }
4111 
4112  for (i = 0; i < indent; i++)
4113  printf("\t");
4114  printf("%s", ptype);
4115 
4116  if (path->parent)
4117  {
4118  printf("(");
4119  print_relids(root, path->parent->relids);
4120  printf(")");
4121  }
4122  if (path->param_info)
4123  {
4124  printf(" required_outer (");
4125  print_relids(root, path->param_info->ppi_req_outer);
4126  printf(")");
4127  }
4128  printf(" rows=%.0f cost=%.2f..%.2f\n",
4129  path->rows, path->startup_cost, path->total_cost);
4130 
4131  if (path->pathkeys)
4132  {
4133  for (i = 0; i < indent; i++)
4134  printf("\t");
4135  printf(" pathkeys: ");
4136  print_pathkeys(path->pathkeys, root->parse->rtable);
4137  }
4138 
4139  if (join)
4140  {
4141  JoinPath *jp = (JoinPath *) path;
4142 
4143  for (i = 0; i < indent; i++)
4144  printf("\t");
4145  printf(" clauses: ");
4146  print_restrictclauses(root, jp->joinrestrictinfo);
4147  printf("\n");
4148 
4149  if (IsA(path, MergePath))
4150  {
4151  MergePath *mp = (MergePath *) path;
4152 
4153  for (i = 0; i < indent; i++)
4154  printf("\t");
4155  printf(" sortouter=%d sortinner=%d materializeinner=%d\n",
4156  ((mp->outersortkeys) ? 1 : 0),
4157  ((mp->innersortkeys) ? 1 : 0),
4158  ((mp->materialize_inner) ? 1 : 0));
4159  }
4160 
4161  print_path(root, jp->outerjoinpath, indent + 1);
4162  print_path(root, jp->innerjoinpath, indent + 1);
4163  }
4164 
4165  if (subpath)
4166  print_path(root, subpath, indent + 1);
4167 }
4168 
4169 void
4170 debug_print_rel(PlannerInfo *root, RelOptInfo *rel)
4171 {
4172  ListCell *l;
4173 
4174  printf("RELOPTINFO (");
4175  print_relids(root, rel->relids);
4176  printf("): rows=%.0f width=%d\n", rel->rows, rel->reltarget->width);
4177 
4178  if (rel->baserestrictinfo)
4179  {
4180  printf("\tbaserestrictinfo: ");
4181  print_restrictclauses(root, rel->baserestrictinfo);
4182  printf("\n");
4183  }
4184 
4185  if (rel->joininfo)
4186  {
4187  printf("\tjoininfo: ");
4188  print_restrictclauses(root, rel->joininfo);
4189  printf("\n");
4190  }
4191 
4192  printf("\tpath list:\n");
4193  foreach(l, rel->pathlist)
4194  print_path(root, lfirst(l), 1);
4196  {
4197  printf("\n\tcheapest parameterized paths:\n");
4198  foreach(l, rel->cheapest_parameterized_paths)
4199  print_path(root, lfirst(l), 1);
4200  }
4201  if (rel->cheapest_startup_path)
4202  {
4203  printf("\n\tcheapest startup path:\n");
4204  print_path(root, rel->cheapest_startup_path, 1);
4205  }
4206  if (rel->cheapest_total_path)
4207  {
4208  printf("\n\tcheapest total path:\n");
4209  print_path(root, rel->cheapest_total_path, 1);
4210  }
4211  printf("\n");
4212  fflush(stdout);
4213 }
4214 
4215 #endif /* OPTIMIZER_DEBUG */
bool has_eclass_joins
Definition: pathnodes.h:751
Path * get_cheapest_path_for_pathkeys(List *paths, List *pathkeys, Relids required_outer, CostSelector cost_criterion, bool require_parallel_safe)
Definition: pathkeys.c:404
void set_subquery_size_estimates(PlannerInfo *root, RelOptInfo *rel)
Definition: costsize.c:5478
RelOptInfo * standard_join_search(PlannerInfo *root, int levels_needed, List *initial_rels)
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Node * limitOffset
Definition: parsenodes.h:171
int varno
Definition: primnodes.h:189
#define NIL
Definition: pg_list.h:65
bool contain_leaked_vars(Node *clause)
Definition: clauses.c:1149
List * outersortkeys
Definition: pathnodes.h:1650
RelOptInfo * make_one_rel(PlannerInfo *root, List *joinlist)
Definition: allpaths.c:153
GatherPath * create_gather_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, PathTarget *target, Relids required_outer, double *rows)
Definition: pathnode.c:1951
#define IsA(nodeptr, _type_)
Definition: nodes.h:587
PathTarget * pathtarget
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List * build_expression_pathkey(PlannerInfo *root, Expr *expr, Relids nullable_relids, Oid opno, Relids rel, bool create_it)
Definition: pathkeys.c:782
Query * parse
Definition: pathnodes.h:162
Index varlevelsup
Definition: primnodes.h:196
#define forboth(cell1, list1, cell2, list2)
Definition: pg_list.h:446
void add_path(RelOptInfo *parent_rel, Path *new_path)
Definition: pathnode.c:422
SubqueryScanPath * create_subqueryscan_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, List *pathkeys, Relids required_outer)
Definition: pathnode.c:1990
RelOptInfo *(* join_search_hook_type)(PlannerInfo *root, int levels_needed, List *initial_rels)
Definition: paths.h:45
List * plan_params
Definition: pathnodes.h:176
bool enable_incremental_sort
Definition: costsize.c:139
List * sortClause
Definition: parsenodes.h:169
RelOptKind reloptkind
Definition: pathnodes.h:678
static void set_base_rel_sizes(PlannerInfo *root)
Definition: allpaths.c:292
Relids * attr_needed
Definition: pathnodes.h:714
List * query_pathkeys
Definition: pathnodes.h:294
List * join_info_list
Definition: pathnodes.h:266
static Path * get_cheapest_parameterized_child_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
Definition: allpaths.c:1879
bool materialize_inner
Definition: pathnodes.h:1653
static ListCell * lnext(const List *l, const ListCell *c)
Definition: pg_list.h:322
static void set_cte_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
Definition: allpaths.c:2423
FromExpr * jointree
Definition: parsenodes.h:148
static void set_foreign_size(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
Definition: allpaths.c:905
PlannerInfo * parent_root
Definition: pathnodes.h:168
#define castNode(_type_, nodeptr)
Definition: nodes.h:605
int compute_parallel_worker(RelOptInfo *rel, double heap_pages, double index_pages, int max_workers)
Definition: allpaths.c:3749
List * build_partition_pathkeys(PlannerInfo *root, RelOptInfo *partrel, ScanDirection scandir, bool *partialkeys)
Definition: pathkeys.c:699
int32 exprTypmod(const Node *expr)
Definition: nodeFuncs.c:267
Path * innerjoinpath
Definition: pathnodes.h:1591
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Definition: allpaths.c:1285
void set_cte_size_estimates(PlannerInfo *root, RelOptInfo *rel, double cte_rows)
Definition: costsize.c:5650
struct Path * cheapest_startup_path
Definition: pathnodes.h:698
Path * create_resultscan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
Definition: pathnode.c:2147
List * baserestrictinfo
Definition: pathnodes.h:745
bool hasAggs
Definition: parsenodes.h:133
void create_index_paths(PlannerInfo *root, RelOptInfo *rel)
Definition: indxpath.c:235
#define Min(x, y)
Definition: c.h:986
int bms_next_member(const Bitmapset *a, int prevbit)
Definition: bitmapset.c:1043
bool expression_returns_set(Node *clause)
Definition: nodeFuncs.c:709
int parallel_workers
Definition: pathnodes.h:1189
set_rel_pathlist_hook_type set_rel_pathlist_hook
Definition: allpaths.c:68
bool pseudoconstant
Definition: pathnodes.h:2064
bool consider_param_startup
Definition: pathnodes.h:688
MaterialPath * create_material_path(RelOptInfo *rel, Path *subpath)
Definition: pathnode.c:1552
bool relation_excluded_by_constraints(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
Definition: plancat.c:1455
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Definition: list.c:600
ParamPathInfo * param_info
Definition: pathnodes.h:1185
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Definition: allpaths.c:3837
List * groupingSets
Definition: parsenodes.h:161
bool partitions_are_ordered(PartitionBoundInfo boundinfo, Bitmapset *live_parts)
Definition: partbounds.c:2860
static void set_namedtuplestore_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
Definition: allpaths.c:2489
List * list_copy(const List *oldlist)
Definition: list.c:1418
bool limit_needed(Query *parse)
Definition: planner.c:2488
Definition: nodes.h:536
#define IS_JOIN_REL(rel)
Definition: pathnodes.h:659
List * list_concat(List *list1, const List *list2)
Definition: list.c:530
List * partial_pathlist
Definition: pathnodes.h:697
List * make_tlist_from_pathtarget(PathTarget *target)
Definition: tlist.c:613
AttrNumber varattno
Definition: primnodes.h:191
bool bms_get_singleton_member(const Bitmapset *a, int *member)
Definition: bitmapset.c:615
bool * unsafeColumns
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Definition: costsize.c:149
static void set_append_rel_size(PlannerInfo *root, RelOptInfo *rel, Index rti, RangeTblEntry *rte)
Definition: allpaths.c:947
#define printf(...)
Definition: port.h:222
#define FirstLowInvalidHeapAttributeNumber
Definition: sysattr.h:27
uint32 BlockNumber
Definition: block.h:31
void generate_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_rows)
Definition: allpaths.c:2608
List * cheapest_parameterized_paths
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Definition: makefuncs.c:689
List * pull_var_clause(Node *node, int flags)
Definition: var.c:597
PathKeysComparison compare_pathkeys(List *keys1, List *keys2)
Definition: pathkeys.c:285
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Definition: equivclass.c:2568
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Definition: clauses.c:452
struct pushdown_safety_info pushdown_safety_info
List * list_copy_tail(const List *oldlist, int nskip)
Definition: list.c:1437
bool funcordinality
Definition: parsenodes.h:1102
IncrementalSortPath * create_incremental_sort_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, List *pathkeys, int presorted_keys, double limit_tuples)
Definition: pathnode.c:2892
static bool recurse_pushdown_safe(Node *setOp, Query *topquery, pushdown_safety_info *safetyInfo)
Definition: allpaths.c:3211
Definition: primnodes.h:186
static void set_result_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
Definition: allpaths.c:2519
static int list_nth_int(const List *list, int n)
Definition: pg_list.h:289
Bitmapset * live_parts
Definition: pathnodes.h:770
static void compare_tlist_datatypes(List *tlist, List *colTypes, pushdown_safety_info *safetyInfo)
Definition: allpaths.c:3346
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Definition: costsize.c:5720
Path * create_functionscan_path(PlannerInfo *root, RelOptInfo *rel, List *pathkeys, Relids required_outer)
Definition: pathnode.c:2018
static void set_base_rel_consider_startup(PlannerInfo *root)
Definition: allpaths.c:249
List * values_lists
Definition: parsenodes.h:1112
Node * quals
Definition: primnodes.h:1565
#define IS_SIMPLE_REL(rel)
Definition: pathnodes.h:654
void pull_varattnos(Node *node, Index varno, Bitmapset **varattnos)
Definition: var.c:281
bool hasDistinctOn
Definition: parsenodes.h:137
signed int int32
Definition: c.h:429
List * windowClause
Definition: parsenodes.h:165
List * targetList
Definition: parsenodes.h:150
Const * makeNullConst(Oid consttype, int32 consttypmod, Oid constcollid)
Definition: makefuncs.c:337
int first_partial_path
Definition: pathnodes.h:1454
int fls(int mask)
Definition: fls.c:55
Path * create_valuesscan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
Definition: pathnode.c:2070
struct RelOptInfo ** simple_rel_array
Definition: pathnodes.h:186
NodeTag pathtype
Definition: pathnodes.h:1180
Relids syn_righthand
Definition: pathnodes.h:2255
#define list_make1(x1)
Definition: pg_list.h:206
List * subpaths
Definition: pathnodes.h:1452
PlannerInfo * subroot
Definition: pathnodes.h:725
bool contain_subplans(Node *clause)
Definition: clauses.c:328
bool pathkeys_count_contained_in(List *keys1, List *keys2, int *n_common)
Definition: pathkeys.c:343
bool is_parallel_safe(PlannerInfo *root, Node *node)
Definition: clauses.c:639
Relids lateral_relids
Definition: pathnodes.h:706
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Definition: mcxt.c:1169
void create_tidscan_paths(PlannerInfo *root, RelOptInfo *rel)
Definition: tidpath.c:459
bool resjunk
Definition: primnodes.h:1462
#define linitial(l)
Definition: pg_list.h:174
IsForeignScanParallelSafe_function IsForeignScanParallelSafe
Definition: fdwapi.h:266
Definition: nodes.h:46
List * rtable
Definition: parsenodes.h:147
List * distinctClause
Definition: parsenodes.h:167
Relids all_baserels
Definition: pathnodes.h:210
void generate_useful_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_rows)
Definition: allpaths.c:2746
#define ERROR
Definition: elog.h:46
List * partitionClause
Definition: parsenodes.h:1391
bool relation_can_be_sorted_early(PlannerInfo *root, RelOptInfo *rel, EquivalenceClass *ec, bool require_parallel_safe)
Definition: equivclass.c:977
static void * list_nth(const List *list, int n)
Definition: pg_list.h:278
Cost startup_cost
Definition: pathnodes.h:1193
List * joinrestrictinfo
Definition: pathnodes.h:1593
bool enable_geqo
Definition: allpaths.c:62
bool parallelModeOK
Definition: pathnodes.h:126
#define IS_DUMMY_REL(r)
Definition: pathnodes.h:1466
RelOptInfo * parent
Definition: pathnodes.h:1182
bool bms_is_subset(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:315
RelOptInfo * fetch_upper_rel(PlannerInfo *root, UpperRelationKind kind, Relids relids)
Definition: relnode.c:1210
static bool targetIsInAllPartitionLists(TargetEntry *tle, Query *query)
Definition: allpaths.c:3379
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Definition: pathnode.c:71
void check_index_predicates(PlannerInfo *root, RelOptInfo *rel)
Definition: indxpath.c:3320
struct Path * cheapest_total_path
Definition: pathnodes.h:699
static RelOptInfo * make_rel_from_joinlist(PlannerInfo *root, List *joinlist)
Definition: allpaths.c:2880
static void set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel, Index rti, RangeTblEntry *rte)
Definition: allpaths.c:1215
Node * limitCount
Definition: parsenodes.h:172
#define PATH_REQ_OUTER(path)
Definition: pathnodes.h:1201
char * c
static void set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
Definition: allpaths.c:592
List * subplans
Definition: pathnodes.h:96
AppendPath * create_append_path(PlannerInfo *root, RelOptInfo *rel, List *subpaths, List *partial_subpaths, List *pathkeys, Relids required_outer, int parallel_workers, bool parallel_aware, double rows)
Definition: pathnode.c:1244
static void set_dummy_rel_pathlist(RelOptInfo *rel)
Definition: allpaths.c:2047
List * joininfo
Definition: pathnodes.h:749
List * convert_subquery_pathkeys(PlannerInfo *root, RelOptInfo *rel, List *subquery_pathkeys, List *subquery_tlist)
Definition: pathkeys.c:838
void check_stack_depth(void)
Definition: postgres.c:3469
PlannerGlobal * glob
Definition: pathnodes.h:164
MergeAppendPath * create_merge_append_path(PlannerInfo *root, RelOptInfo *rel, List *subpaths, List *pathkeys, Relids required_outer)
Definition: pathnode.c:1404
static void remove_unused_subquery_outputs(Query *subquery, RelOptInfo *rel)
Definition: allpaths.c:3608
struct FdwRoutine * fdwroutine
Definition: pathnodes.h:736
static void set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel, Index rti, RangeTblEntry *rte)
Definition: allpaths.c:2106
int nparts
Definition: pathnodes.h:761
GetForeignRelSize_function GetForeignRelSize
Definition: fdwapi.h:209
AttrNumber resno
Definition: primnodes.h:1456
static void set_foreign_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
Definition: allpaths.c:929
static ListCell * list_head(const List *l)
Definition: pg_list.h:125
Relids relids
Definition: pathnodes.h:681
int min_parallel_index_scan_size
Definition: allpaths.c:65
int simple_rel_array_size
Definition: pathnodes.h:187
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Definition: joinrels.c:71
void print_expr(const Node *expr, const List *rtable)
Definition: print.c:321
static Path * get_singleton_append_subpath(Path *path)
Definition: allpaths.c:2013
#define rt_fetch(rangetable_index, rangetable)
Definition: parsetree.h:31
Path * get_cheapest_parallel_safe_total_inner(List *paths)
Definition: pathkeys.c:482
Index relid
Definition: pathnodes.h:709
Path * create_worktablescan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
Definition: pathnode.c:2173
bool contain_window_function(Node *clause)
Definition: clauses.c:212
List * lappend(List *list, void *datum)
Definition: list.c:336
static void set_tablesample_rel_size(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
Definition: allpaths.c:817
RangeTblEntry ** simple_rte_array
Definition: pathnodes.h:194
GetForeignPaths_function GetForeignPaths
Definition: fdwapi.h:210
Expr * clause
Definition: pathnodes.h:2056
bool bms_is_empty(const Bitmapset *a)
Definition: bitmapset.c:701
static void set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
Definition: allpaths.c:767
SampleScanGetSampleSize_function SampleScanGetSampleSize
Definition: tsmapi.h:68
static void check_output_expressions(Query *subquery, pushdown_safety_info *safetyInfo)
Definition: allpaths.c:3278
Node * ReplaceVarsFromTargetList(Node *node, int target_varno, int sublevels_up, RangeTblEntry *target_rte, List *targetlist, ReplaceVarsNoMatchOption nomatch_option, int nomatch_varno, bool *outer_hasSubLinks)
void set_cheapest(RelOptInfo *parent_rel)
Definition: pathnode.c:244
List * exprs
Definition: pathnodes.h:1110
void print_pathkeys(const List *pathkeys, const List *rtable)
Definition: print.c:426
#define PVC_INCLUDE_PLACEHOLDERS
Definition: optimizer.h:190
bool pathkeys_contained_in(List *keys1, List *keys2)
Definition: pathkeys.c:324
Path * outerjoinpath
Definition: pathnodes.h:1590
void set_namedtuplestore_size_estimates(PlannerInfo *root, RelOptInfo *rel)
Definition: costsize.c:5687
bool consider_partitionwise_join
Definition: pathnodes.h:754
join_search_hook_type join_search_hook
Definition: allpaths.c:71
BMS_Membership bms_membership(const Bitmapset *a)
Definition: bitmapset.c:672
void * palloc0(Size size)
Definition: mcxt.c:1093
static void set_base_rel_pathlists(PlannerInfo *root)
Definition: allpaths.c:335
void mark_dummy_rel(RelOptInfo *rel)
Definition: joinrels.c:1261
Path * create_samplescan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
Definition: pathnode.c:954
int rel_parallel_workers
Definition: pathnodes.h:727
List * append_rel_list
Definition: pathnodes.h:284
List * cte_plan_ids
Definition: pathnodes.h:244
Path * create_tablefuncscan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
Definition: pathnode.c:2044
bool self_reference
Definition: parsenodes.h:1119
void set_baserel_size_estimates(PlannerInfo *root, RelOptInfo *rel)
Definition: costsize.c:4923
struct PartitionBoundInfoData * boundinfo
Definition: pathnodes.h:764
unsigned int Index
Definition: c.h:549
int geqo_threshold
Definition: allpaths.c:63
RTEKind rtekind
Definition: pathnodes.h:711
RelOptInfo * geqo(PlannerInfo *root, int number_of_rels, List *initial_rels)
Definition: geqo_main.c:67
static void set_tablesample_rel_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
Definition: allpaths.c:857
bool security_barrier
Definition: parsenodes.h:1043
static void set_tablefunc_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
Definition: allpaths.c:2399
int32 get_typavgwidth(Oid typid, int32 typmod)
Definition: lsyscache.c:2525
#define InvalidOid
Definition: postgres_ext.h:36
bool targetIsInSortList(TargetEntry *tle, Oid sortop, List *sortList)
GatherMergePath * create_gather_merge_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, PathTarget *target, List *pathkeys, Relids required_outer, double *rows)
Definition: pathnode.c:1860
SortPath * create_sort_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, List *pathkeys, double limit_tuples)
Definition: pathnode.c:2941
Cost total_cost
Definition: pathnodes.h:1194
bool hasTargetSRFs
Definition: parsenodes.h:135
List * lcons(void *datum, List *list)
Definition: list.c:468
List * pathkeys
Definition: pathnodes.h:1196
static void set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel, Index rti, RangeTblEntry *rte)
Definition: allpaths.c:471
TsmRoutine * GetTsmRoutine(Oid tsmhandler)
Definition: tablesample.c:27
#define Max(x, y)
Definition: c.h:980
BlockNumber pages
Definition: pathnodes.h:720
Selectivity tuple_fraction
Definition: pathnodes.h:340
#define Assert(condition)
Definition: c.h:804
#define lfirst(lc)
Definition: pg_list.h:169
char * aliasname
Definition: primnodes.h:42
bool hasWindowFuncs
Definition: parsenodes.h:134
void(* set_rel_pathlist_hook_type)(PlannerInfo *root, RelOptInfo *rel, Index rti, RangeTblEntry *rte)
Definition: paths.h:29
List ** join_rel_level
Definition: pathnodes.h:239
List * functions
Definition: parsenodes.h:1101
static bool has_multiple_baserels(PlannerInfo *root)
Definition: allpaths.c:2073
Expr * expr
Definition: primnodes.h:1455
Cardinality rows
Definition: pathnodes.h:684
char func_parallel(Oid funcid)
Definition: lsyscache.c:1770
JoinType jointype
Definition: pathnodes.h:2256
EquivalenceClass * pk_eclass
Definition: pathnodes.h:1066
struct RelOptInfo ** part_rels
Definition: pathnodes.h:768
struct Path * non_recursive_path
Definition: pathnodes.h:365
bool enable_partitionwise_join
Definition: costsize.c:147
static void subquery_push_qual(Query *subquery, RangeTblEntry *rte, Index rti, Node *qual)
Definition: allpaths.c:3514
Oid exprType(const Node *expr)
Definition: nodeFuncs.c:41
static int list_length(const List *l)
Definition: pg_list.h:149
int min_parallel_table_scan_size
Definition: allpaths.c:64
#define for_each_from(cell, lst, N)
Definition: pg_list.h:393
Oid exprCollation(const Node *expr)
Definition: nodeFuncs.c:759
Cardinality plan_rows
Definition: plannodes.h:123
SetOperation op
Definition: parsenodes.h:1723
static void recurse_push_qual(Node *setOp, Query *topquery, RangeTblEntry *rte, Index rti, Node *qual)
Definition: allpaths.c:3561
Index ctelevelsup
Definition: parsenodes.h:1118
bool consider_parallel
Definition: pathnodes.h:689
Bitmapset * bms_add_member(Bitmapset *a, int x)
Definition: bitmapset.c:736
List * innersortkeys
Definition: pathnodes.h:1651
bool repeatable_across_scans
Definition: tsmapi.h:65
static List * get_useful_pathkeys_for_relation(PlannerInfo *root, RelOptInfo *rel, bool require_parallel_safe)
Definition: allpaths.c:2678
Bitmapset * Relids
Definition: pathnodes.h:28
Index query_level
Definition: pathnodes.h:166
#define InvalidAttrNumber
Definition: attnum.h:23
#define nodeTag(nodeptr)
Definition: nodes.h:541
static bool qual_is_pushdown_safe(Query *subquery, Index rti, RestrictInfo *rinfo, pushdown_safety_info *safetyInfo)
Definition: allpaths.c:3422
char get_rel_persistence(Oid relid)
Definition: lsyscache.c:2049
RTEKind rtekind
Definition: parsenodes.h:1007
static bool subquery_is_pushdown_safe(Query *subquery, Query *topquery, pushdown_safety_info *safetyInfo)
Definition: allpaths.c:3155
Cardinality total_table_pages
Definition: pathnodes.h:337
List * cteList
Definition: parsenodes.h:145
char * ctename
Definition: parsenodes.h:1117
Node * setOperations
Definition: parsenodes.h:177
Query * subquery
Definition: parsenodes.h:1042
List * groupClause
Definition: parsenodes.h:158
Path * reparameterize_path(PlannerInfo *root, Path *path, Relids required_outer, double loop_count)
Definition: pathnode.c:3844
AttrNumber max_attr
Definition: pathnodes.h:713
void set_values_size_estimates(PlannerInfo *root, RelOptInfo *rel)
Definition: costsize.c:5618
void add_partial_path(RelOptInfo *parent_rel, Path *new_path)
Definition: pathnode.c:749
#define IS_PARTITIONED_REL(rel)
Definition: pathnodes.h:786
bool hasSubLinks
Definition: parsenodes.h:136
static void set_plain_rel_size(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
Definition: allpaths.c:575
void list_free(List *list)
Definition: list.c:1391
#define elog(elevel,...)
Definition: elog.h:232
int i
Index ressortgroupref
Definition: primnodes.h:1458
bool has_useful_pathkeys(PlannerInfo *root, RelOptInfo *rel)
Definition: pathkeys.c:1910
PartitionScheme part_scheme
Definition: pathnodes.h:760
bool parallel_aware
Definition: pathnodes.h:1187
List * initial_rels
Definition: pathnodes.h:304
void set_tablefunc_size_estimates(PlannerInfo *root, RelOptInfo *rel)
Definition: costsize.c:5596
List * pathlist
Definition: pathnodes.h:695
static void create_plain_partial_paths(PlannerInfo *root, RelOptInfo *rel)
Definition: allpaths.c:797
Relids ppi_req_outer
Definition: pathnodes.h:1141
void set_function_size_estimates(PlannerInfo *root, RelOptInfo *rel)
Definition: costsize.c:5558
Index child_relid
Definition: pathnodes.h:2307
Cardinality rows
Definition: pathnodes.h:1192
Alias * eref
Definition: parsenodes.h:1153
RelOptInfo * find_base_rel(PlannerInfo *root, int relid)
Definition: relnode.c:375
static void generate_orderedappend_paths(PlannerInfo *root, RelOptInfo *rel, List *live_childrels, List *all_child_pathkeys)
Definition: allpaths.c:1673
#define copyObject(obj)
Definition: nodes.h:652
static void set_function_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
Definition: allpaths.c:2311
Node * havingQual
Definition: parsenodes.h:163
Index parent_relid
Definition: pathnodes.h:2306
int32 * attr_widths
Definition: pathnodes.h:715
void create_partial_bitmap_paths(PlannerInfo *root, RelOptInfo *rel, Path *bitmapqual)
Definition: allpaths.c:3713
void set_foreign_size_estimates(PlannerInfo *root, RelOptInfo *rel)
Definition: costsize.c:5749
Definition: nodes.h:229
double clamp_row_est(double nrows)
Definition: costsize.c:199
Definition: regcomp.c:237
static void accumulate_append_subpath(Path *path, List **subpaths, List **special_subpaths)
Definition: allpaths.c:1967
int max_parallel_workers_per_gather
Definition: costsize.c:131
Definition: pg_list.h:50
bool bms_is_member(int x, const Bitmapset *a)
Definition: bitmapset.c:427
struct PathTarget * reltarget
Definition: pathnodes.h:692
static void set_values_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
Definition: allpaths.c:2379
struct TableSampleClause * tablesample
Definition: parsenodes.h:1037
int16 AttrNumber
Definition: attnum.h:21
static void set_rel_size(PlannerInfo *root, RelOptInfo *rel, Index rti, RangeTblEntry *rte)
Definition: allpaths.c:362
List * subplan_params
Definition: pathnodes.h:726
PlannerInfo * subquery_planner(PlannerGlobal *glob, Query *parse, PlannerInfo *parent_root, bool hasRecursion, double tuple_fraction)
Definition: planner.c:596
Path * create_seqscan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer, int parallel_workers)
Definition: pathnode.c:929
double compute_bitmap_pages(PlannerInfo *root, RelOptInfo *baserel, Path *bitmapqual, int loop_count, Cost *cost, double *tuple)
Definition: costsize.c:6075
Datum subpath(PG_FUNCTION_ARGS)
Definition: ltree_op.c:241
#define lfirst_oid(lc)
Definition: pg_list.h:171
bool bms_equal(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:94
static struct subre * parse(struct vars *, int, int, struct state *, struct state *)
Definition: regcomp.c:673
Node * adjust_appendrel_attrs(PlannerInfo *root, Node *node, int nappinfos, AppendRelInfo **appinfos)
Definition: appendinfo.c:195
unsigned char bool
Definition: c.h:391
BitmapHeapPath * create_bitmap_heap_path(PlannerInfo *root, RelOptInfo *rel, Path *bitmapqual, Relids required_outer, double loop_count, int parallel_degree)
Definition: pathnode.c:1046
Path * create_namedtuplestorescan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
Definition: pathnode.c:2121
static void set_worktable_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
Definition: allpaths.c:2549
Path * create_ctescan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
Definition: pathnode.c:2096
AttrNumber min_attr
Definition: pathnodes.h:712
Cardinality tuples
Definition: pathnodes.h:721