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pathnode.c
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1 /*-------------------------------------------------------------------------
2  *
3  * pathnode.c
4  * Routines to manipulate pathlists and create path nodes
5  *
6  * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
7  * Portions Copyright (c) 1994, Regents of the University of California
8  *
9  *
10  * IDENTIFICATION
11  * src/backend/optimizer/util/pathnode.c
12  *
13  *-------------------------------------------------------------------------
14  */
15 #include "postgres.h"
16 
17 #include <math.h>
18 
19 #include "miscadmin.h"
20 #include "nodes/nodeFuncs.h"
21 #include "optimizer/clauses.h"
22 #include "optimizer/cost.h"
23 #include "optimizer/pathnode.h"
24 #include "optimizer/paths.h"
25 #include "optimizer/planmain.h"
26 #include "optimizer/restrictinfo.h"
27 #include "optimizer/var.h"
28 #include "parser/parsetree.h"
29 #include "utils/lsyscache.h"
30 #include "utils/selfuncs.h"
31 
32 
33 typedef enum
34 {
35  COSTS_EQUAL, /* path costs are fuzzily equal */
36  COSTS_BETTER1, /* first path is cheaper than second */
37  COSTS_BETTER2, /* second path is cheaper than first */
38  COSTS_DIFFERENT /* neither path dominates the other on cost */
40 
41 /*
42  * STD_FUZZ_FACTOR is the normal fuzz factor for compare_path_costs_fuzzily.
43  * XXX is it worth making this user-controllable? It provides a tradeoff
44  * between planner runtime and the accuracy of path cost comparisons.
45  */
46 #define STD_FUZZ_FACTOR 1.01
47 
48 static List *translate_sub_tlist(List *tlist, int relid);
49 
50 
51 /*****************************************************************************
52  * MISC. PATH UTILITIES
53  *****************************************************************************/
54 
55 /*
56  * compare_path_costs
57  * Return -1, 0, or +1 according as path1 is cheaper, the same cost,
58  * or more expensive than path2 for the specified criterion.
59  */
60 int
61 compare_path_costs(Path *path1, Path *path2, CostSelector criterion)
62 {
63  if (criterion == STARTUP_COST)
64  {
65  if (path1->startup_cost < path2->startup_cost)
66  return -1;
67  if (path1->startup_cost > path2->startup_cost)
68  return +1;
69 
70  /*
71  * If paths have the same startup cost (not at all unlikely), order
72  * them by total cost.
73  */
74  if (path1->total_cost < path2->total_cost)
75  return -1;
76  if (path1->total_cost > path2->total_cost)
77  return +1;
78  }
79  else
80  {
81  if (path1->total_cost < path2->total_cost)
82  return -1;
83  if (path1->total_cost > path2->total_cost)
84  return +1;
85 
86  /*
87  * If paths have the same total cost, order them by startup cost.
88  */
89  if (path1->startup_cost < path2->startup_cost)
90  return -1;
91  if (path1->startup_cost > path2->startup_cost)
92  return +1;
93  }
94  return 0;
95 }
96 
97 /*
98  * compare_path_fractional_costs
99  * Return -1, 0, or +1 according as path1 is cheaper, the same cost,
100  * or more expensive than path2 for fetching the specified fraction
101  * of the total tuples.
102  *
103  * If fraction is <= 0 or > 1, we interpret it as 1, ie, we select the
104  * path with the cheaper total_cost.
105  */
106 int
108  double fraction)
109 {
110  Cost cost1,
111  cost2;
112 
113  if (fraction <= 0.0 || fraction >= 1.0)
114  return compare_path_costs(path1, path2, TOTAL_COST);
115  cost1 = path1->startup_cost +
116  fraction * (path1->total_cost - path1->startup_cost);
117  cost2 = path2->startup_cost +
118  fraction * (path2->total_cost - path2->startup_cost);
119  if (cost1 < cost2)
120  return -1;
121  if (cost1 > cost2)
122  return +1;
123  return 0;
124 }
125 
126 /*
127  * compare_path_costs_fuzzily
128  * Compare the costs of two paths to see if either can be said to
129  * dominate the other.
130  *
131  * We use fuzzy comparisons so that add_path() can avoid keeping both of
132  * a pair of paths that really have insignificantly different cost.
133  *
134  * The fuzz_factor argument must be 1.0 plus delta, where delta is the
135  * fraction of the smaller cost that is considered to be a significant
136  * difference. For example, fuzz_factor = 1.01 makes the fuzziness limit
137  * be 1% of the smaller cost.
138  *
139  * The two paths are said to have "equal" costs if both startup and total
140  * costs are fuzzily the same. Path1 is said to be better than path2 if
141  * it has fuzzily better startup cost and fuzzily no worse total cost,
142  * or if it has fuzzily better total cost and fuzzily no worse startup cost.
143  * Path2 is better than path1 if the reverse holds. Finally, if one path
144  * is fuzzily better than the other on startup cost and fuzzily worse on
145  * total cost, we just say that their costs are "different", since neither
146  * dominates the other across the whole performance spectrum.
147  *
148  * This function also enforces a policy rule that paths for which the relevant
149  * one of parent->consider_startup and parent->consider_param_startup is false
150  * cannot survive comparisons solely on the grounds of good startup cost, so
151  * we never return COSTS_DIFFERENT when that is true for the total-cost loser.
152  * (But if total costs are fuzzily equal, we compare startup costs anyway,
153  * in hopes of eliminating one path or the other.)
154  */
155 static PathCostComparison
156 compare_path_costs_fuzzily(Path *path1, Path *path2, double fuzz_factor)
157 {
158 #define CONSIDER_PATH_STARTUP_COST(p) \
159  ((p)->param_info == NULL ? (p)->parent->consider_startup : (p)->parent->consider_param_startup)
160 
161  /*
162  * Check total cost first since it's more likely to be different; many
163  * paths have zero startup cost.
164  */
165  if (path1->total_cost > path2->total_cost * fuzz_factor)
166  {
167  /* path1 fuzzily worse on total cost */
168  if (CONSIDER_PATH_STARTUP_COST(path1) &&
169  path2->startup_cost > path1->startup_cost * fuzz_factor)
170  {
171  /* ... but path2 fuzzily worse on startup, so DIFFERENT */
172  return COSTS_DIFFERENT;
173  }
174  /* else path2 dominates */
175  return COSTS_BETTER2;
176  }
177  if (path2->total_cost > path1->total_cost * fuzz_factor)
178  {
179  /* path2 fuzzily worse on total cost */
180  if (CONSIDER_PATH_STARTUP_COST(path2) &&
181  path1->startup_cost > path2->startup_cost * fuzz_factor)
182  {
183  /* ... but path1 fuzzily worse on startup, so DIFFERENT */
184  return COSTS_DIFFERENT;
185  }
186  /* else path1 dominates */
187  return COSTS_BETTER1;
188  }
189  /* fuzzily the same on total cost ... */
190  if (path1->startup_cost > path2->startup_cost * fuzz_factor)
191  {
192  /* ... but path1 fuzzily worse on startup, so path2 wins */
193  return COSTS_BETTER2;
194  }
195  if (path2->startup_cost > path1->startup_cost * fuzz_factor)
196  {
197  /* ... but path2 fuzzily worse on startup, so path1 wins */
198  return COSTS_BETTER1;
199  }
200  /* fuzzily the same on both costs */
201  return COSTS_EQUAL;
202 
203 #undef CONSIDER_PATH_STARTUP_COST
204 }
205 
206 /*
207  * set_cheapest
208  * Find the minimum-cost paths from among a relation's paths,
209  * and save them in the rel's cheapest-path fields.
210  *
211  * cheapest_total_path is normally the cheapest-total-cost unparameterized
212  * path; but if there are no unparameterized paths, we assign it to be the
213  * best (cheapest least-parameterized) parameterized path. However, only
214  * unparameterized paths are considered candidates for cheapest_startup_path,
215  * so that will be NULL if there are no unparameterized paths.
216  *
217  * The cheapest_parameterized_paths list collects all parameterized paths
218  * that have survived the add_path() tournament for this relation. (Since
219  * add_path ignores pathkeys for a parameterized path, these will be paths
220  * that have best cost or best row count for their parameterization. We
221  * may also have both a parallel-safe and a non-parallel-safe path in some
222  * cases for the same parameterization in some cases, but this should be
223  * relatively rare since, most typically, all paths for the same relation
224  * will be parallel-safe or none of them will.)
225  *
226  * cheapest_parameterized_paths always includes the cheapest-total
227  * unparameterized path, too, if there is one; the users of that list find
228  * it more convenient if that's included.
229  *
230  * This is normally called only after we've finished constructing the path
231  * list for the rel node.
232  */
233 void
235 {
236  Path *cheapest_startup_path;
237  Path *cheapest_total_path;
238  Path *best_param_path;
239  List *parameterized_paths;
240  ListCell *p;
241 
242  Assert(IsA(parent_rel, RelOptInfo));
243 
244  if (parent_rel->pathlist == NIL)
245  elog(ERROR, "could not devise a query plan for the given query");
246 
247  cheapest_startup_path = cheapest_total_path = best_param_path = NULL;
248  parameterized_paths = NIL;
249 
250  foreach(p, parent_rel->pathlist)
251  {
252  Path *path = (Path *) lfirst(p);
253  int cmp;
254 
255  if (path->param_info)
256  {
257  /* Parameterized path, so add it to parameterized_paths */
258  parameterized_paths = lappend(parameterized_paths, path);
259 
260  /*
261  * If we have an unparameterized cheapest-total, we no longer care
262  * about finding the best parameterized path, so move on.
263  */
264  if (cheapest_total_path)
265  continue;
266 
267  /*
268  * Otherwise, track the best parameterized path, which is the one
269  * with least total cost among those of the minimum
270  * parameterization.
271  */
272  if (best_param_path == NULL)
273  best_param_path = path;
274  else
275  {
276  switch (bms_subset_compare(PATH_REQ_OUTER(path),
277  PATH_REQ_OUTER(best_param_path)))
278  {
279  case BMS_EQUAL:
280  /* keep the cheaper one */
281  if (compare_path_costs(path, best_param_path,
282  TOTAL_COST) < 0)
283  best_param_path = path;
284  break;
285  case BMS_SUBSET1:
286  /* new path is less-parameterized */
287  best_param_path = path;
288  break;
289  case BMS_SUBSET2:
290  /* old path is less-parameterized, keep it */
291  break;
292  case BMS_DIFFERENT:
293 
294  /*
295  * This means that neither path has the least possible
296  * parameterization for the rel. We'll sit on the old
297  * path until something better comes along.
298  */
299  break;
300  }
301  }
302  }
303  else
304  {
305  /* Unparameterized path, so consider it for cheapest slots */
306  if (cheapest_total_path == NULL)
307  {
308  cheapest_startup_path = cheapest_total_path = path;
309  continue;
310  }
311 
312  /*
313  * If we find two paths of identical costs, try to keep the
314  * better-sorted one. The paths might have unrelated sort
315  * orderings, in which case we can only guess which might be
316  * better to keep, but if one is superior then we definitely
317  * should keep that one.
318  */
319  cmp = compare_path_costs(cheapest_startup_path, path, STARTUP_COST);
320  if (cmp > 0 ||
321  (cmp == 0 &&
322  compare_pathkeys(cheapest_startup_path->pathkeys,
323  path->pathkeys) == PATHKEYS_BETTER2))
324  cheapest_startup_path = path;
325 
326  cmp = compare_path_costs(cheapest_total_path, path, TOTAL_COST);
327  if (cmp > 0 ||
328  (cmp == 0 &&
329  compare_pathkeys(cheapest_total_path->pathkeys,
330  path->pathkeys) == PATHKEYS_BETTER2))
331  cheapest_total_path = path;
332  }
333  }
334 
335  /* Add cheapest unparameterized path, if any, to parameterized_paths */
336  if (cheapest_total_path)
337  parameterized_paths = lcons(cheapest_total_path, parameterized_paths);
338 
339  /*
340  * If there is no unparameterized path, use the best parameterized path as
341  * cheapest_total_path (but not as cheapest_startup_path).
342  */
343  if (cheapest_total_path == NULL)
344  cheapest_total_path = best_param_path;
345  Assert(cheapest_total_path != NULL);
346 
347  parent_rel->cheapest_startup_path = cheapest_startup_path;
348  parent_rel->cheapest_total_path = cheapest_total_path;
349  parent_rel->cheapest_unique_path = NULL; /* computed only if needed */
350  parent_rel->cheapest_parameterized_paths = parameterized_paths;
351 }
352 
353 /*
354  * add_path
355  * Consider a potential implementation path for the specified parent rel,
356  * and add it to the rel's pathlist if it is worthy of consideration.
357  * A path is worthy if it has a better sort order (better pathkeys) or
358  * cheaper cost (on either dimension), or generates fewer rows, than any
359  * existing path that has the same or superset parameterization rels.
360  * We also consider parallel-safe paths more worthy than others.
361  *
362  * We also remove from the rel's pathlist any old paths that are dominated
363  * by new_path --- that is, new_path is cheaper, at least as well ordered,
364  * generates no more rows, requires no outer rels not required by the old
365  * path, and is no less parallel-safe.
366  *
367  * In most cases, a path with a superset parameterization will generate
368  * fewer rows (since it has more join clauses to apply), so that those two
369  * figures of merit move in opposite directions; this means that a path of
370  * one parameterization can seldom dominate a path of another. But such
371  * cases do arise, so we make the full set of checks anyway.
372  *
373  * There are two policy decisions embedded in this function, along with
374  * its sibling add_path_precheck. First, we treat all parameterized paths
375  * as having NIL pathkeys, so that they cannot win comparisons on the
376  * basis of sort order. This is to reduce the number of parameterized
377  * paths that are kept; see discussion in src/backend/optimizer/README.
378  *
379  * Second, we only consider cheap startup cost to be interesting if
380  * parent_rel->consider_startup is true for an unparameterized path, or
381  * parent_rel->consider_param_startup is true for a parameterized one.
382  * Again, this allows discarding useless paths sooner.
383  *
384  * The pathlist is kept sorted by total_cost, with cheaper paths
385  * at the front. Within this routine, that's simply a speed hack:
386  * doing it that way makes it more likely that we will reject an inferior
387  * path after a few comparisons, rather than many comparisons.
388  * However, add_path_precheck relies on this ordering to exit early
389  * when possible.
390  *
391  * NOTE: discarded Path objects are immediately pfree'd to reduce planner
392  * memory consumption. We dare not try to free the substructure of a Path,
393  * since much of it may be shared with other Paths or the query tree itself;
394  * but just recycling discarded Path nodes is a very useful savings in
395  * a large join tree. We can recycle the List nodes of pathlist, too.
396  *
397  * As noted in optimizer/README, deleting a previously-accepted Path is
398  * safe because we know that Paths of this rel cannot yet be referenced
399  * from any other rel, such as a higher-level join. However, in some cases
400  * it is possible that a Path is referenced by another Path for its own
401  * rel; we must not delete such a Path, even if it is dominated by the new
402  * Path. Currently this occurs only for IndexPath objects, which may be
403  * referenced as children of BitmapHeapPaths as well as being paths in
404  * their own right. Hence, we don't pfree IndexPaths when rejecting them.
405  *
406  * 'parent_rel' is the relation entry to which the path corresponds.
407  * 'new_path' is a potential path for parent_rel.
408  *
409  * Returns nothing, but modifies parent_rel->pathlist.
410  */
411 void
412 add_path(RelOptInfo *parent_rel, Path *new_path)
413 {
414  bool accept_new = true; /* unless we find a superior old path */
415  ListCell *insert_after = NULL; /* where to insert new item */
416  List *new_path_pathkeys;
417  ListCell *p1;
418  ListCell *p1_prev;
419  ListCell *p1_next;
420 
421  /*
422  * This is a convenient place to check for query cancel --- no part of the
423  * planner goes very long without calling add_path().
424  */
426 
427  /* Pretend parameterized paths have no pathkeys, per comment above */
428  new_path_pathkeys = new_path->param_info ? NIL : new_path->pathkeys;
429 
430  /*
431  * Loop to check proposed new path against old paths. Note it is possible
432  * for more than one old path to be tossed out because new_path dominates
433  * it.
434  *
435  * We can't use foreach here because the loop body may delete the current
436  * list cell.
437  */
438  p1_prev = NULL;
439  for (p1 = list_head(parent_rel->pathlist); p1 != NULL; p1 = p1_next)
440  {
441  Path *old_path = (Path *) lfirst(p1);
442  bool remove_old = false; /* unless new proves superior */
443  PathCostComparison costcmp;
444  PathKeysComparison keyscmp;
445  BMS_Comparison outercmp;
446 
447  p1_next = lnext(p1);
448 
449  /*
450  * Do a fuzzy cost comparison with standard fuzziness limit.
451  */
452  costcmp = compare_path_costs_fuzzily(new_path, old_path,
454 
455  /*
456  * If the two paths compare differently for startup and total cost,
457  * then we want to keep both, and we can skip comparing pathkeys and
458  * required_outer rels. If they compare the same, proceed with the
459  * other comparisons. Row count is checked last. (We make the tests
460  * in this order because the cost comparison is most likely to turn
461  * out "different", and the pathkeys comparison next most likely. As
462  * explained above, row count very seldom makes a difference, so even
463  * though it's cheap to compare there's not much point in checking it
464  * earlier.)
465  */
466  if (costcmp != COSTS_DIFFERENT)
467  {
468  /* Similarly check to see if either dominates on pathkeys */
469  List *old_path_pathkeys;
470 
471  old_path_pathkeys = old_path->param_info ? NIL : old_path->pathkeys;
472  keyscmp = compare_pathkeys(new_path_pathkeys,
473  old_path_pathkeys);
474  if (keyscmp != PATHKEYS_DIFFERENT)
475  {
476  switch (costcmp)
477  {
478  case COSTS_EQUAL:
479  outercmp = bms_subset_compare(PATH_REQ_OUTER(new_path),
480  PATH_REQ_OUTER(old_path));
481  if (keyscmp == PATHKEYS_BETTER1)
482  {
483  if ((outercmp == BMS_EQUAL ||
484  outercmp == BMS_SUBSET1) &&
485  new_path->rows <= old_path->rows &&
486  new_path->parallel_safe >= old_path->parallel_safe)
487  remove_old = true; /* new dominates old */
488  }
489  else if (keyscmp == PATHKEYS_BETTER2)
490  {
491  if ((outercmp == BMS_EQUAL ||
492  outercmp == BMS_SUBSET2) &&
493  new_path->rows >= old_path->rows &&
494  new_path->parallel_safe <= old_path->parallel_safe)
495  accept_new = false; /* old dominates new */
496  }
497  else /* keyscmp == PATHKEYS_EQUAL */
498  {
499  if (outercmp == BMS_EQUAL)
500  {
501  /*
502  * Same pathkeys and outer rels, and fuzzily
503  * the same cost, so keep just one; to decide
504  * which, first check parallel-safety, then
505  * rows, then do a fuzzy cost comparison with
506  * very small fuzz limit. (We used to do an
507  * exact cost comparison, but that results in
508  * annoying platform-specific plan variations
509  * due to roundoff in the cost estimates.) If
510  * things are still tied, arbitrarily keep
511  * only the old path. Notice that we will
512  * keep only the old path even if the
513  * less-fuzzy comparison decides the startup
514  * and total costs compare differently.
515  */
516  if (new_path->parallel_safe >
517  old_path->parallel_safe)
518  remove_old = true; /* new dominates old */
519  else if (new_path->parallel_safe <
520  old_path->parallel_safe)
521  accept_new = false; /* old dominates new */
522  else if (new_path->rows < old_path->rows)
523  remove_old = true; /* new dominates old */
524  else if (new_path->rows > old_path->rows)
525  accept_new = false; /* old dominates new */
526  else if (compare_path_costs_fuzzily(new_path,
527  old_path,
528  1.0000000001) == COSTS_BETTER1)
529  remove_old = true; /* new dominates old */
530  else
531  accept_new = false; /* old equals or
532  * dominates new */
533  }
534  else if (outercmp == BMS_SUBSET1 &&
535  new_path->rows <= old_path->rows &&
536  new_path->parallel_safe >= old_path->parallel_safe)
537  remove_old = true; /* new dominates old */
538  else if (outercmp == BMS_SUBSET2 &&
539  new_path->rows >= old_path->rows &&
540  new_path->parallel_safe <= old_path->parallel_safe)
541  accept_new = false; /* old dominates new */
542  /* else different parameterizations, keep both */
543  }
544  break;
545  case COSTS_BETTER1:
546  if (keyscmp != PATHKEYS_BETTER2)
547  {
548  outercmp = bms_subset_compare(PATH_REQ_OUTER(new_path),
549  PATH_REQ_OUTER(old_path));
550  if ((outercmp == BMS_EQUAL ||
551  outercmp == BMS_SUBSET1) &&
552  new_path->rows <= old_path->rows &&
553  new_path->parallel_safe >= old_path->parallel_safe)
554  remove_old = true; /* new dominates old */
555  }
556  break;
557  case COSTS_BETTER2:
558  if (keyscmp != PATHKEYS_BETTER1)
559  {
560  outercmp = bms_subset_compare(PATH_REQ_OUTER(new_path),
561  PATH_REQ_OUTER(old_path));
562  if ((outercmp == BMS_EQUAL ||
563  outercmp == BMS_SUBSET2) &&
564  new_path->rows >= old_path->rows &&
565  new_path->parallel_safe <= old_path->parallel_safe)
566  accept_new = false; /* old dominates new */
567  }
568  break;
569  case COSTS_DIFFERENT:
570 
571  /*
572  * can't get here, but keep this case to keep compiler
573  * quiet
574  */
575  break;
576  }
577  }
578  }
579 
580  /*
581  * Remove current element from pathlist if dominated by new.
582  */
583  if (remove_old)
584  {
585  parent_rel->pathlist = list_delete_cell(parent_rel->pathlist,
586  p1, p1_prev);
587 
588  /*
589  * Delete the data pointed-to by the deleted cell, if possible
590  */
591  if (!IsA(old_path, IndexPath))
592  pfree(old_path);
593  /* p1_prev does not advance */
594  }
595  else
596  {
597  /* new belongs after this old path if it has cost >= old's */
598  if (new_path->total_cost >= old_path->total_cost)
599  insert_after = p1;
600  /* p1_prev advances */
601  p1_prev = p1;
602  }
603 
604  /*
605  * If we found an old path that dominates new_path, we can quit
606  * scanning the pathlist; we will not add new_path, and we assume
607  * new_path cannot dominate any other elements of the pathlist.
608  */
609  if (!accept_new)
610  break;
611  }
612 
613  if (accept_new)
614  {
615  /* Accept the new path: insert it at proper place in pathlist */
616  if (insert_after)
617  lappend_cell(parent_rel->pathlist, insert_after, new_path);
618  else
619  parent_rel->pathlist = lcons(new_path, parent_rel->pathlist);
620  }
621  else
622  {
623  /* Reject and recycle the new path */
624  if (!IsA(new_path, IndexPath))
625  pfree(new_path);
626  }
627 }
628 
629 /*
630  * add_path_precheck
631  * Check whether a proposed new path could possibly get accepted.
632  * We assume we know the path's pathkeys and parameterization accurately,
633  * and have lower bounds for its costs.
634  *
635  * Note that we do not know the path's rowcount, since getting an estimate for
636  * that is too expensive to do before prechecking. We assume here that paths
637  * of a superset parameterization will generate fewer rows; if that holds,
638  * then paths with different parameterizations cannot dominate each other
639  * and so we can simply ignore existing paths of another parameterization.
640  * (In the infrequent cases where that rule of thumb fails, add_path will
641  * get rid of the inferior path.)
642  *
643  * At the time this is called, we haven't actually built a Path structure,
644  * so the required information has to be passed piecemeal.
645  */
646 bool
648  Cost startup_cost, Cost total_cost,
649  List *pathkeys, Relids required_outer)
650 {
651  List *new_path_pathkeys;
652  bool consider_startup;
653  ListCell *p1;
654 
655  /* Pretend parameterized paths have no pathkeys, per add_path policy */
656  new_path_pathkeys = required_outer ? NIL : pathkeys;
657 
658  /* Decide whether new path's startup cost is interesting */
659  consider_startup = required_outer ? parent_rel->consider_param_startup : parent_rel->consider_startup;
660 
661  foreach(p1, parent_rel->pathlist)
662  {
663  Path *old_path = (Path *) lfirst(p1);
664  PathKeysComparison keyscmp;
665 
666  /*
667  * We are looking for an old_path with the same parameterization (and
668  * by assumption the same rowcount) that dominates the new path on
669  * pathkeys as well as both cost metrics. If we find one, we can
670  * reject the new path.
671  *
672  * Cost comparisons here should match compare_path_costs_fuzzily.
673  */
674  if (total_cost > old_path->total_cost * STD_FUZZ_FACTOR)
675  {
676  /* new path can win on startup cost only if consider_startup */
677  if (startup_cost > old_path->startup_cost * STD_FUZZ_FACTOR ||
678  !consider_startup)
679  {
680  /* new path loses on cost, so check pathkeys... */
681  List *old_path_pathkeys;
682 
683  old_path_pathkeys = old_path->param_info ? NIL : old_path->pathkeys;
684  keyscmp = compare_pathkeys(new_path_pathkeys,
685  old_path_pathkeys);
686  if (keyscmp == PATHKEYS_EQUAL ||
687  keyscmp == PATHKEYS_BETTER2)
688  {
689  /* new path does not win on pathkeys... */
690  if (bms_equal(required_outer, PATH_REQ_OUTER(old_path)))
691  {
692  /* Found an old path that dominates the new one */
693  return false;
694  }
695  }
696  }
697  }
698  else
699  {
700  /*
701  * Since the pathlist is sorted by total_cost, we can stop looking
702  * once we reach a path with a total_cost larger than the new
703  * path's.
704  */
705  break;
706  }
707  }
708 
709  return true;
710 }
711 
712 /*
713  * add_partial_path
714  * Like add_path, our goal here is to consider whether a path is worthy
715  * of being kept around, but the considerations here are a bit different.
716  * A partial path is one which can be executed in any number of workers in
717  * parallel such that each worker will generate a subset of the path's
718  * overall result.
719  *
720  * As in add_path, the partial_pathlist is kept sorted with the cheapest
721  * total path in front. This is depended on by multiple places, which
722  * just take the front entry as the cheapest path without searching.
723  *
724  * We don't generate parameterized partial paths for several reasons. Most
725  * importantly, they're not safe to execute, because there's nothing to
726  * make sure that a parallel scan within the parameterized portion of the
727  * plan is running with the same value in every worker at the same time.
728  * Fortunately, it seems unlikely to be worthwhile anyway, because having
729  * each worker scan the entire outer relation and a subset of the inner
730  * relation will generally be a terrible plan. The inner (parameterized)
731  * side of the plan will be small anyway. There could be rare cases where
732  * this wins big - e.g. if join order constraints put a 1-row relation on
733  * the outer side of the topmost join with a parameterized plan on the inner
734  * side - but we'll have to be content not to handle such cases until
735  * somebody builds an executor infrastructure that can cope with them.
736  *
737  * Because we don't consider parameterized paths here, we also don't
738  * need to consider the row counts as a measure of quality: every path will
739  * produce the same number of rows. Neither do we need to consider startup
740  * costs: parallelism is only used for plans that will be run to completion.
741  * Therefore, this routine is much simpler than add_path: it needs to
742  * consider only pathkeys and total cost.
743  *
744  * As with add_path, we pfree paths that are found to be dominated by
745  * another partial path; this requires that there be no other references to
746  * such paths yet. Hence, GatherPaths must not be created for a rel until
747  * we're done creating all partial paths for it. Unlike add_path, we don't
748  * take an exception for IndexPaths as partial index paths won't be
749  * referenced by partial BitmapHeapPaths.
750  */
751 void
752 add_partial_path(RelOptInfo *parent_rel, Path *new_path)
753 {
754  bool accept_new = true; /* unless we find a superior old path */
755  ListCell *insert_after = NULL; /* where to insert new item */
756  ListCell *p1;
757  ListCell *p1_prev;
758  ListCell *p1_next;
759 
760  /* Check for query cancel. */
762 
763  /*
764  * As in add_path, throw out any paths which are dominated by the new
765  * path, but throw out the new path if some existing path dominates it.
766  */
767  p1_prev = NULL;
768  for (p1 = list_head(parent_rel->partial_pathlist); p1 != NULL;
769  p1 = p1_next)
770  {
771  Path *old_path = (Path *) lfirst(p1);
772  bool remove_old = false; /* unless new proves superior */
773  PathKeysComparison keyscmp;
774 
775  p1_next = lnext(p1);
776 
777  /* Compare pathkeys. */
778  keyscmp = compare_pathkeys(new_path->pathkeys, old_path->pathkeys);
779 
780  /* Unless pathkeys are incompable, keep just one of the two paths. */
781  if (keyscmp != PATHKEYS_DIFFERENT)
782  {
783  if (new_path->total_cost > old_path->total_cost * STD_FUZZ_FACTOR)
784  {
785  /* New path costs more; keep it only if pathkeys are better. */
786  if (keyscmp != PATHKEYS_BETTER1)
787  accept_new = false;
788  }
789  else if (old_path->total_cost > new_path->total_cost
790  * STD_FUZZ_FACTOR)
791  {
792  /* Old path costs more; keep it only if pathkeys are better. */
793  if (keyscmp != PATHKEYS_BETTER2)
794  remove_old = true;
795  }
796  else if (keyscmp == PATHKEYS_BETTER1)
797  {
798  /* Costs are about the same, new path has better pathkeys. */
799  remove_old = true;
800  }
801  else if (keyscmp == PATHKEYS_BETTER2)
802  {
803  /* Costs are about the same, old path has better pathkeys. */
804  accept_new = false;
805  }
806  else if (old_path->total_cost > new_path->total_cost * 1.0000000001)
807  {
808  /* Pathkeys are the same, and the old path costs more. */
809  remove_old = true;
810  }
811  else
812  {
813  /*
814  * Pathkeys are the same, and new path isn't materially
815  * cheaper.
816  */
817  accept_new = false;
818  }
819  }
820 
821  /*
822  * Remove current element from partial_pathlist if dominated by new.
823  */
824  if (remove_old)
825  {
826  parent_rel->partial_pathlist =
827  list_delete_cell(parent_rel->partial_pathlist, p1, p1_prev);
828  pfree(old_path);
829  /* p1_prev does not advance */
830  }
831  else
832  {
833  /* new belongs after this old path if it has cost >= old's */
834  if (new_path->total_cost >= old_path->total_cost)
835  insert_after = p1;
836  /* p1_prev advances */
837  p1_prev = p1;
838  }
839 
840  /*
841  * If we found an old path that dominates new_path, we can quit
842  * scanning the partial_pathlist; we will not add new_path, and we
843  * assume new_path cannot dominate any later path.
844  */
845  if (!accept_new)
846  break;
847  }
848 
849  if (accept_new)
850  {
851  /* Accept the new path: insert it at proper place */
852  if (insert_after)
853  lappend_cell(parent_rel->partial_pathlist, insert_after, new_path);
854  else
855  parent_rel->partial_pathlist =
856  lcons(new_path, parent_rel->partial_pathlist);
857  }
858  else
859  {
860  /* Reject and recycle the new path */
861  pfree(new_path);
862  }
863 }
864 
865 /*
866  * add_partial_path_precheck
867  * Check whether a proposed new partial path could possibly get accepted.
868  *
869  * Unlike add_path_precheck, we can ignore startup cost and parameterization,
870  * since they don't matter for partial paths (see add_partial_path). But
871  * we do want to make sure we don't add a partial path if there's already
872  * a complete path that dominates it, since in that case the proposed path
873  * is surely a loser.
874  */
875 bool
876 add_partial_path_precheck(RelOptInfo *parent_rel, Cost total_cost,
877  List *pathkeys)
878 {
879  ListCell *p1;
880 
881  /*
882  * Our goal here is twofold. First, we want to find out whether this path
883  * is clearly inferior to some existing partial path. If so, we want to
884  * reject it immediately. Second, we want to find out whether this path
885  * is clearly superior to some existing partial path -- at least, modulo
886  * final cost computations. If so, we definitely want to consider it.
887  *
888  * Unlike add_path(), we always compare pathkeys here. This is because we
889  * expect partial_pathlist to be very short, and getting a definitive
890  * answer at this stage avoids the need to call add_path_precheck.
891  */
892  foreach(p1, parent_rel->partial_pathlist)
893  {
894  Path *old_path = (Path *) lfirst(p1);
895  PathKeysComparison keyscmp;
896 
897  keyscmp = compare_pathkeys(pathkeys, old_path->pathkeys);
898  if (keyscmp != PATHKEYS_DIFFERENT)
899  {
900  if (total_cost > old_path->total_cost * STD_FUZZ_FACTOR &&
901  keyscmp != PATHKEYS_BETTER1)
902  return false;
903  if (old_path->total_cost > total_cost * STD_FUZZ_FACTOR &&
904  keyscmp != PATHKEYS_BETTER2)
905  return true;
906  }
907  }
908 
909  /*
910  * This path is neither clearly inferior to an existing partial path nor
911  * clearly good enough that it might replace one. Compare it to
912  * non-parallel plans. If it loses even before accounting for the cost of
913  * the Gather node, we should definitely reject it.
914  *
915  * Note that we pass the total_cost to add_path_precheck twice. This is
916  * because it's never advantageous to consider the startup cost of a
917  * partial path; the resulting plans, if run in parallel, will be run to
918  * completion.
919  */
920  if (!add_path_precheck(parent_rel, total_cost, total_cost, pathkeys,
921  NULL))
922  return false;
923 
924  return true;
925 }
926 
927 
928 /*****************************************************************************
929  * PATH NODE CREATION ROUTINES
930  *****************************************************************************/
931 
932 /*
933  * create_seqscan_path
934  * Creates a path corresponding to a sequential scan, returning the
935  * pathnode.
936  */
937 Path *
939  Relids required_outer, int parallel_workers)
940 {
941  Path *pathnode = makeNode(Path);
942 
943  pathnode->pathtype = T_SeqScan;
944  pathnode->parent = rel;
945  pathnode->pathtarget = rel->reltarget;
946  pathnode->param_info = get_baserel_parampathinfo(root, rel,
947  required_outer);
948  pathnode->parallel_aware = parallel_workers > 0 ? true : false;
949  pathnode->parallel_safe = rel->consider_parallel;
950  pathnode->parallel_workers = parallel_workers;
951  pathnode->pathkeys = NIL; /* seqscan has unordered result */
952 
953  cost_seqscan(pathnode, root, rel, pathnode->param_info);
954 
955  return pathnode;
956 }
957 
958 /*
959  * create_samplescan_path
960  * Creates a path node for a sampled table scan.
961  */
962 Path *
964 {
965  Path *pathnode = makeNode(Path);
966 
967  pathnode->pathtype = T_SampleScan;
968  pathnode->parent = rel;
969  pathnode->pathtarget = rel->reltarget;
970  pathnode->param_info = get_baserel_parampathinfo(root, rel,
971  required_outer);
972  pathnode->parallel_aware = false;
973  pathnode->parallel_safe = rel->consider_parallel;
974  pathnode->parallel_workers = 0;
975  pathnode->pathkeys = NIL; /* samplescan has unordered result */
976 
977  cost_samplescan(pathnode, root, rel, pathnode->param_info);
978 
979  return pathnode;
980 }
981 
982 /*
983  * create_index_path
984  * Creates a path node for an index scan.
985  *
986  * 'index' is a usable index.
987  * 'indexclauses' is a list of RestrictInfo nodes representing clauses
988  * to be used as index qual conditions in the scan.
989  * 'indexclausecols' is an integer list of index column numbers (zero based)
990  * the indexclauses can be used with.
991  * 'indexorderbys' is a list of bare expressions (no RestrictInfos)
992  * to be used as index ordering operators in the scan.
993  * 'indexorderbycols' is an integer list of index column numbers (zero based)
994  * the ordering operators can be used with.
995  * 'pathkeys' describes the ordering of the path.
996  * 'indexscandir' is ForwardScanDirection or BackwardScanDirection
997  * for an ordered index, or NoMovementScanDirection for
998  * an unordered index.
999  * 'indexonly' is true if an index-only scan is wanted.
1000  * 'required_outer' is the set of outer relids for a parameterized path.
1001  * 'loop_count' is the number of repetitions of the indexscan to factor into
1002  * estimates of caching behavior.
1003  * 'partial_path' is true if constructing a parallel index scan path.
1004  *
1005  * Returns the new path node.
1006  */
1007 IndexPath *
1010  List *indexclauses,
1011  List *indexclausecols,
1012  List *indexorderbys,
1013  List *indexorderbycols,
1014  List *pathkeys,
1015  ScanDirection indexscandir,
1016  bool indexonly,
1017  Relids required_outer,
1018  double loop_count,
1019  bool partial_path)
1020 {
1021  IndexPath *pathnode = makeNode(IndexPath);
1022  RelOptInfo *rel = index->rel;
1023  List *indexquals,
1024  *indexqualcols;
1025 
1026  pathnode->path.pathtype = indexonly ? T_IndexOnlyScan : T_IndexScan;
1027  pathnode->path.parent = rel;
1028  pathnode->path.pathtarget = rel->reltarget;
1029  pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
1030  required_outer);
1031  pathnode->path.parallel_aware = false;
1032  pathnode->path.parallel_safe = rel->consider_parallel;
1033  pathnode->path.parallel_workers = 0;
1034  pathnode->path.pathkeys = pathkeys;
1035 
1036  /* Convert clauses to indexquals the executor can handle */
1037  expand_indexqual_conditions(index, indexclauses, indexclausecols,
1038  &indexquals, &indexqualcols);
1039 
1040  /* Fill in the pathnode */
1041  pathnode->indexinfo = index;
1042  pathnode->indexclauses = indexclauses;
1043  pathnode->indexquals = indexquals;
1044  pathnode->indexqualcols = indexqualcols;
1045  pathnode->indexorderbys = indexorderbys;
1046  pathnode->indexorderbycols = indexorderbycols;
1047  pathnode->indexscandir = indexscandir;
1048 
1049  cost_index(pathnode, root, loop_count, partial_path);
1050 
1051  return pathnode;
1052 }
1053 
1054 /*
1055  * create_bitmap_heap_path
1056  * Creates a path node for a bitmap scan.
1057  *
1058  * 'bitmapqual' is a tree of IndexPath, BitmapAndPath, and BitmapOrPath nodes.
1059  * 'required_outer' is the set of outer relids for a parameterized path.
1060  * 'loop_count' is the number of repetitions of the indexscan to factor into
1061  * estimates of caching behavior.
1062  *
1063  * loop_count should match the value used when creating the component
1064  * IndexPaths.
1065  */
1068  RelOptInfo *rel,
1069  Path *bitmapqual,
1070  Relids required_outer,
1071  double loop_count,
1072  int parallel_degree)
1073 {
1074  BitmapHeapPath *pathnode = makeNode(BitmapHeapPath);
1075 
1076  pathnode->path.pathtype = T_BitmapHeapScan;
1077  pathnode->path.parent = rel;
1078  pathnode->path.pathtarget = rel->reltarget;
1079  pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
1080  required_outer);
1081  pathnode->path.parallel_aware = parallel_degree > 0 ? true : false;
1082  pathnode->path.parallel_safe = rel->consider_parallel;
1083  pathnode->path.parallel_workers = parallel_degree;
1084  pathnode->path.pathkeys = NIL; /* always unordered */
1085 
1086  pathnode->bitmapqual = bitmapqual;
1087 
1088  cost_bitmap_heap_scan(&pathnode->path, root, rel,
1089  pathnode->path.param_info,
1090  bitmapqual, loop_count);
1091 
1092  return pathnode;
1093 }
1094 
1095 /*
1096  * create_bitmap_and_path
1097  * Creates a path node representing a BitmapAnd.
1098  */
1099 BitmapAndPath *
1101  RelOptInfo *rel,
1102  List *bitmapquals)
1103 {
1104  BitmapAndPath *pathnode = makeNode(BitmapAndPath);
1105 
1106  pathnode->path.pathtype = T_BitmapAnd;
1107  pathnode->path.parent = rel;
1108  pathnode->path.pathtarget = rel->reltarget;
1109  pathnode->path.param_info = NULL; /* not used in bitmap trees */
1110 
1111  /*
1112  * Currently, a BitmapHeapPath, BitmapAndPath, or BitmapOrPath will be
1113  * parallel-safe if and only if rel->consider_parallel is set. So, we can
1114  * set the flag for this path based only on the relation-level flag,
1115  * without actually iterating over the list of children.
1116  */
1117  pathnode->path.parallel_aware = false;
1118  pathnode->path.parallel_safe = rel->consider_parallel;
1119  pathnode->path.parallel_workers = 0;
1120 
1121  pathnode->path.pathkeys = NIL; /* always unordered */
1122 
1123  pathnode->bitmapquals = bitmapquals;
1124 
1125  /* this sets bitmapselectivity as well as the regular cost fields: */
1126  cost_bitmap_and_node(pathnode, root);
1127 
1128  return pathnode;
1129 }
1130 
1131 /*
1132  * create_bitmap_or_path
1133  * Creates a path node representing a BitmapOr.
1134  */
1135 BitmapOrPath *
1137  RelOptInfo *rel,
1138  List *bitmapquals)
1139 {
1140  BitmapOrPath *pathnode = makeNode(BitmapOrPath);
1141 
1142  pathnode->path.pathtype = T_BitmapOr;
1143  pathnode->path.parent = rel;
1144  pathnode->path.pathtarget = rel->reltarget;
1145  pathnode->path.param_info = NULL; /* not used in bitmap trees */
1146 
1147  /*
1148  * Currently, a BitmapHeapPath, BitmapAndPath, or BitmapOrPath will be
1149  * parallel-safe if and only if rel->consider_parallel is set. So, we can
1150  * set the flag for this path based only on the relation-level flag,
1151  * without actually iterating over the list of children.
1152  */
1153  pathnode->path.parallel_aware = false;
1154  pathnode->path.parallel_safe = rel->consider_parallel;
1155  pathnode->path.parallel_workers = 0;
1156 
1157  pathnode->path.pathkeys = NIL; /* always unordered */
1158 
1159  pathnode->bitmapquals = bitmapquals;
1160 
1161  /* this sets bitmapselectivity as well as the regular cost fields: */
1162  cost_bitmap_or_node(pathnode, root);
1163 
1164  return pathnode;
1165 }
1166 
1167 /*
1168  * create_tidscan_path
1169  * Creates a path corresponding to a scan by TID, returning the pathnode.
1170  */
1171 TidPath *
1173  Relids required_outer)
1174 {
1175  TidPath *pathnode = makeNode(TidPath);
1176 
1177  pathnode->path.pathtype = T_TidScan;
1178  pathnode->path.parent = rel;
1179  pathnode->path.pathtarget = rel->reltarget;
1180  pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
1181  required_outer);
1182  pathnode->path.parallel_aware = false;
1183  pathnode->path.parallel_safe = rel->consider_parallel;
1184  pathnode->path.parallel_workers = 0;
1185  pathnode->path.pathkeys = NIL; /* always unordered */
1186 
1187  pathnode->tidquals = tidquals;
1188 
1189  cost_tidscan(&pathnode->path, root, rel, tidquals,
1190  pathnode->path.param_info);
1191 
1192  return pathnode;
1193 }
1194 
1195 /*
1196  * create_append_path
1197  * Creates a path corresponding to an Append plan, returning the
1198  * pathnode.
1199  *
1200  * Note that we must handle subpaths = NIL, representing a dummy access path.
1201  */
1202 AppendPath *
1203 create_append_path(RelOptInfo *rel, List *subpaths, Relids required_outer,
1204  int parallel_workers, List *partitioned_rels)
1205 {
1206  AppendPath *pathnode = makeNode(AppendPath);
1207  ListCell *l;
1208 
1209  pathnode->path.pathtype = T_Append;
1210  pathnode->path.parent = rel;
1211  pathnode->path.pathtarget = rel->reltarget;
1213  required_outer);
1214  pathnode->path.parallel_aware = false;
1215  pathnode->path.parallel_safe = rel->consider_parallel;
1216  pathnode->path.parallel_workers = parallel_workers;
1217  pathnode->path.pathkeys = NIL; /* result is always considered unsorted */
1218  pathnode->partitioned_rels = list_copy(partitioned_rels);
1219  pathnode->subpaths = subpaths;
1220 
1221  /*
1222  * We don't bother with inventing a cost_append(), but just do it here.
1223  *
1224  * Compute rows and costs as sums of subplan rows and costs. We charge
1225  * nothing extra for the Append itself, which perhaps is too optimistic,
1226  * but since it doesn't do any selection or projection, it is a pretty
1227  * cheap node.
1228  */
1229  pathnode->path.rows = 0;
1230  pathnode->path.startup_cost = 0;
1231  pathnode->path.total_cost = 0;
1232  foreach(l, subpaths)
1233  {
1234  Path *subpath = (Path *) lfirst(l);
1235 
1236  pathnode->path.rows += subpath->rows;
1237 
1238  if (l == list_head(subpaths)) /* first node? */
1239  pathnode->path.startup_cost = subpath->startup_cost;
1240  pathnode->path.total_cost += subpath->total_cost;
1241  pathnode->path.parallel_safe = pathnode->path.parallel_safe &&
1242  subpath->parallel_safe;
1243 
1244  /* All child paths must have same parameterization */
1245  Assert(bms_equal(PATH_REQ_OUTER(subpath), required_outer));
1246  }
1247 
1248  return pathnode;
1249 }
1250 
1251 /*
1252  * create_merge_append_path
1253  * Creates a path corresponding to a MergeAppend plan, returning the
1254  * pathnode.
1255  */
1258  RelOptInfo *rel,
1259  List *subpaths,
1260  List *pathkeys,
1261  Relids required_outer,
1262  List *partitioned_rels)
1263 {
1265  Cost input_startup_cost;
1266  Cost input_total_cost;
1267  ListCell *l;
1268 
1269  pathnode->path.pathtype = T_MergeAppend;
1270  pathnode->path.parent = rel;
1271  pathnode->path.pathtarget = rel->reltarget;
1273  required_outer);
1274  pathnode->path.parallel_aware = false;
1275  pathnode->path.parallel_safe = rel->consider_parallel;
1276  pathnode->path.parallel_workers = 0;
1277  pathnode->path.pathkeys = pathkeys;
1278  pathnode->partitioned_rels = list_copy(partitioned_rels);
1279  pathnode->subpaths = subpaths;
1280 
1281  /*
1282  * Apply query-wide LIMIT if known and path is for sole base relation.
1283  * (Handling this at this low level is a bit klugy.)
1284  */
1285  if (bms_equal(rel->relids, root->all_baserels))
1286  pathnode->limit_tuples = root->limit_tuples;
1287  else
1288  pathnode->limit_tuples = -1.0;
1289 
1290  /*
1291  * Add up the sizes and costs of the input paths.
1292  */
1293  pathnode->path.rows = 0;
1294  input_startup_cost = 0;
1295  input_total_cost = 0;
1296  foreach(l, subpaths)
1297  {
1298  Path *subpath = (Path *) lfirst(l);
1299 
1300  pathnode->path.rows += subpath->rows;
1301  pathnode->path.parallel_safe = pathnode->path.parallel_safe &&
1302  subpath->parallel_safe;
1303 
1304  if (pathkeys_contained_in(pathkeys, subpath->pathkeys))
1305  {
1306  /* Subpath is adequately ordered, we won't need to sort it */
1307  input_startup_cost += subpath->startup_cost;
1308  input_total_cost += subpath->total_cost;
1309  }
1310  else
1311  {
1312  /* We'll need to insert a Sort node, so include cost for that */
1313  Path sort_path; /* dummy for result of cost_sort */
1314 
1315  cost_sort(&sort_path,
1316  root,
1317  pathkeys,
1318  subpath->total_cost,
1319  subpath->parent->tuples,
1320  subpath->pathtarget->width,
1321  0.0,
1322  work_mem,
1323  pathnode->limit_tuples);
1324  input_startup_cost += sort_path.startup_cost;
1325  input_total_cost += sort_path.total_cost;
1326  }
1327 
1328  /* All child paths must have same parameterization */
1329  Assert(bms_equal(PATH_REQ_OUTER(subpath), required_outer));
1330  }
1331 
1332  /* Now we can compute total costs of the MergeAppend */
1333  cost_merge_append(&pathnode->path, root,
1334  pathkeys, list_length(subpaths),
1335  input_startup_cost, input_total_cost,
1336  pathnode->path.rows);
1337 
1338  return pathnode;
1339 }
1340 
1341 /*
1342  * create_result_path
1343  * Creates a path representing a Result-and-nothing-else plan.
1344  *
1345  * This is only used for degenerate cases, such as a query with an empty
1346  * jointree.
1347  */
1348 ResultPath *
1350  PathTarget *target, List *resconstantqual)
1351 {
1352  ResultPath *pathnode = makeNode(ResultPath);
1353 
1354  pathnode->path.pathtype = T_Result;
1355  pathnode->path.parent = rel;
1356  pathnode->path.pathtarget = target;
1357  pathnode->path.param_info = NULL; /* there are no other rels... */
1358  pathnode->path.parallel_aware = false;
1359  pathnode->path.parallel_safe = rel->consider_parallel;
1360  pathnode->path.parallel_workers = 0;
1361  pathnode->path.pathkeys = NIL;
1362  pathnode->quals = resconstantqual;
1363 
1364  /* Hardly worth defining a cost_result() function ... just do it */
1365  pathnode->path.rows = 1;
1366  pathnode->path.startup_cost = target->cost.startup;
1367  pathnode->path.total_cost = target->cost.startup +
1368  cpu_tuple_cost + target->cost.per_tuple;
1369  if (resconstantqual)
1370  {
1371  QualCost qual_cost;
1372 
1373  cost_qual_eval(&qual_cost, resconstantqual, root);
1374  /* resconstantqual is evaluated once at startup */
1375  pathnode->path.startup_cost += qual_cost.startup + qual_cost.per_tuple;
1376  pathnode->path.total_cost += qual_cost.startup + qual_cost.per_tuple;
1377  }
1378 
1379  return pathnode;
1380 }
1381 
1382 /*
1383  * create_material_path
1384  * Creates a path corresponding to a Material plan, returning the
1385  * pathnode.
1386  */
1387 MaterialPath *
1389 {
1390  MaterialPath *pathnode = makeNode(MaterialPath);
1391 
1392  Assert(subpath->parent == rel);
1393 
1394  pathnode->path.pathtype = T_Material;
1395  pathnode->path.parent = rel;
1396  pathnode->path.pathtarget = rel->reltarget;
1397  pathnode->path.param_info = subpath->param_info;
1398  pathnode->path.parallel_aware = false;
1399  pathnode->path.parallel_safe = rel->consider_parallel &&
1400  subpath->parallel_safe;
1401  pathnode->path.parallel_workers = subpath->parallel_workers;
1402  pathnode->path.pathkeys = subpath->pathkeys;
1403 
1404  pathnode->subpath = subpath;
1405 
1406  cost_material(&pathnode->path,
1407  subpath->startup_cost,
1408  subpath->total_cost,
1409  subpath->rows,
1410  subpath->pathtarget->width);
1411 
1412  return pathnode;
1413 }
1414 
1415 /*
1416  * create_unique_path
1417  * Creates a path representing elimination of distinct rows from the
1418  * input data. Distinct-ness is defined according to the needs of the
1419  * semijoin represented by sjinfo. If it is not possible to identify
1420  * how to make the data unique, NULL is returned.
1421  *
1422  * If used at all, this is likely to be called repeatedly on the same rel;
1423  * and the input subpath should always be the same (the cheapest_total path
1424  * for the rel). So we cache the result.
1425  */
1426 UniquePath *
1428  SpecialJoinInfo *sjinfo)
1429 {
1430  UniquePath *pathnode;
1431  Path sort_path; /* dummy for result of cost_sort */
1432  Path agg_path; /* dummy for result of cost_agg */
1433  MemoryContext oldcontext;
1434  int numCols;
1435 
1436  /* Caller made a mistake if subpath isn't cheapest_total ... */
1437  Assert(subpath == rel->cheapest_total_path);
1438  Assert(subpath->parent == rel);
1439  /* ... or if SpecialJoinInfo is the wrong one */
1440  Assert(sjinfo->jointype == JOIN_SEMI);
1441  Assert(bms_equal(rel->relids, sjinfo->syn_righthand));
1442 
1443  /* If result already cached, return it */
1444  if (rel->cheapest_unique_path)
1445  return (UniquePath *) rel->cheapest_unique_path;
1446 
1447  /* If it's not possible to unique-ify, return NULL */
1448  if (!(sjinfo->semi_can_btree || sjinfo->semi_can_hash))
1449  return NULL;
1450 
1451  /*
1452  * We must ensure path struct and subsidiary data are allocated in main
1453  * planning context; otherwise GEQO memory management causes trouble.
1454  */
1455  oldcontext = MemoryContextSwitchTo(root->planner_cxt);
1456 
1457  pathnode = makeNode(UniquePath);
1458 
1459  pathnode->path.pathtype = T_Unique;
1460  pathnode->path.parent = rel;
1461  pathnode->path.pathtarget = rel->reltarget;
1462  pathnode->path.param_info = subpath->param_info;
1463  pathnode->path.parallel_aware = false;
1464  pathnode->path.parallel_safe = rel->consider_parallel &&
1465  subpath->parallel_safe;
1466  pathnode->path.parallel_workers = subpath->parallel_workers;
1467 
1468  /*
1469  * Assume the output is unsorted, since we don't necessarily have pathkeys
1470  * to represent it. (This might get overridden below.)
1471  */
1472  pathnode->path.pathkeys = NIL;
1473 
1474  pathnode->subpath = subpath;
1475  pathnode->in_operators = sjinfo->semi_operators;
1476  pathnode->uniq_exprs = sjinfo->semi_rhs_exprs;
1477 
1478  /*
1479  * If the input is a relation and it has a unique index that proves the
1480  * semi_rhs_exprs are unique, then we don't need to do anything. Note
1481  * that relation_has_unique_index_for automatically considers restriction
1482  * clauses for the rel, as well.
1483  */
1484  if (rel->rtekind == RTE_RELATION && sjinfo->semi_can_btree &&
1486  sjinfo->semi_rhs_exprs,
1487  sjinfo->semi_operators))
1488  {
1489  pathnode->umethod = UNIQUE_PATH_NOOP;
1490  pathnode->path.rows = rel->rows;
1491  pathnode->path.startup_cost = subpath->startup_cost;
1492  pathnode->path.total_cost = subpath->total_cost;
1493  pathnode->path.pathkeys = subpath->pathkeys;
1494 
1495  rel->cheapest_unique_path = (Path *) pathnode;
1496 
1497  MemoryContextSwitchTo(oldcontext);
1498 
1499  return pathnode;
1500  }
1501 
1502  /*
1503  * If the input is a subquery whose output must be unique already, then we
1504  * don't need to do anything. The test for uniqueness has to consider
1505  * exactly which columns we are extracting; for example "SELECT DISTINCT
1506  * x,y" doesn't guarantee that x alone is distinct. So we cannot check for
1507  * this optimization unless semi_rhs_exprs consists only of simple Vars
1508  * referencing subquery outputs. (Possibly we could do something with
1509  * expressions in the subquery outputs, too, but for now keep it simple.)
1510  */
1511  if (rel->rtekind == RTE_SUBQUERY)
1512  {
1513  RangeTblEntry *rte = planner_rt_fetch(rel->relid, root);
1514 
1516  {
1517  List *sub_tlist_colnos;
1518 
1519  sub_tlist_colnos = translate_sub_tlist(sjinfo->semi_rhs_exprs,
1520  rel->relid);
1521 
1522  if (sub_tlist_colnos &&
1524  sub_tlist_colnos,
1525  sjinfo->semi_operators))
1526  {
1527  pathnode->umethod = UNIQUE_PATH_NOOP;
1528  pathnode->path.rows = rel->rows;
1529  pathnode->path.startup_cost = subpath->startup_cost;
1530  pathnode->path.total_cost = subpath->total_cost;
1531  pathnode->path.pathkeys = subpath->pathkeys;
1532 
1533  rel->cheapest_unique_path = (Path *) pathnode;
1534 
1535  MemoryContextSwitchTo(oldcontext);
1536 
1537  return pathnode;
1538  }
1539  }
1540  }
1541 
1542  /* Estimate number of output rows */
1543  pathnode->path.rows = estimate_num_groups(root,
1544  sjinfo->semi_rhs_exprs,
1545  rel->rows,
1546  NULL);
1547  numCols = list_length(sjinfo->semi_rhs_exprs);
1548 
1549  if (sjinfo->semi_can_btree)
1550  {
1551  /*
1552  * Estimate cost for sort+unique implementation
1553  */
1554  cost_sort(&sort_path, root, NIL,
1555  subpath->total_cost,
1556  rel->rows,
1557  subpath->pathtarget->width,
1558  0.0,
1559  work_mem,
1560  -1.0);
1561 
1562  /*
1563  * Charge one cpu_operator_cost per comparison per input tuple. We
1564  * assume all columns get compared at most of the tuples. (XXX
1565  * probably this is an overestimate.) This should agree with
1566  * create_upper_unique_path.
1567  */
1568  sort_path.total_cost += cpu_operator_cost * rel->rows * numCols;
1569  }
1570 
1571  if (sjinfo->semi_can_hash)
1572  {
1573  /*
1574  * Estimate the overhead per hashtable entry at 64 bytes (same as in
1575  * planner.c).
1576  */
1577  int hashentrysize = subpath->pathtarget->width + 64;
1578 
1579  if (hashentrysize * pathnode->path.rows > work_mem * 1024L)
1580  {
1581  /*
1582  * We should not try to hash. Hack the SpecialJoinInfo to
1583  * remember this, in case we come through here again.
1584  */
1585  sjinfo->semi_can_hash = false;
1586  }
1587  else
1588  cost_agg(&agg_path, root,
1589  AGG_HASHED, NULL,
1590  numCols, pathnode->path.rows,
1591  subpath->startup_cost,
1592  subpath->total_cost,
1593  rel->rows);
1594  }
1595 
1596  if (sjinfo->semi_can_btree && sjinfo->semi_can_hash)
1597  {
1598  if (agg_path.total_cost < sort_path.total_cost)
1599  pathnode->umethod = UNIQUE_PATH_HASH;
1600  else
1601  pathnode->umethod = UNIQUE_PATH_SORT;
1602  }
1603  else if (sjinfo->semi_can_btree)
1604  pathnode->umethod = UNIQUE_PATH_SORT;
1605  else if (sjinfo->semi_can_hash)
1606  pathnode->umethod = UNIQUE_PATH_HASH;
1607  else
1608  {
1609  /* we can get here only if we abandoned hashing above */
1610  MemoryContextSwitchTo(oldcontext);
1611  return NULL;
1612  }
1613 
1614  if (pathnode->umethod == UNIQUE_PATH_HASH)
1615  {
1616  pathnode->path.startup_cost = agg_path.startup_cost;
1617  pathnode->path.total_cost = agg_path.total_cost;
1618  }
1619  else
1620  {
1621  pathnode->path.startup_cost = sort_path.startup_cost;
1622  pathnode->path.total_cost = sort_path.total_cost;
1623  }
1624 
1625  rel->cheapest_unique_path = (Path *) pathnode;
1626 
1627  MemoryContextSwitchTo(oldcontext);
1628 
1629  return pathnode;
1630 }
1631 
1632 /*
1633  * create_gather_merge_path
1634  *
1635  * Creates a path corresponding to a gather merge scan, returning
1636  * the pathnode.
1637  */
1640  PathTarget *target, List *pathkeys,
1641  Relids required_outer, double *rows)
1642 {
1644  Cost input_startup_cost = 0;
1645  Cost input_total_cost = 0;
1646 
1647  Assert(subpath->parallel_safe);
1648  Assert(pathkeys);
1649 
1650  pathnode->path.pathtype = T_GatherMerge;
1651  pathnode->path.parent = rel;
1652  pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
1653  required_outer);
1654  pathnode->path.parallel_aware = false;
1655 
1656  pathnode->subpath = subpath;
1657  pathnode->num_workers = subpath->parallel_workers;
1658  pathnode->path.pathkeys = pathkeys;
1659  pathnode->path.pathtarget = target ? target : rel->reltarget;
1660  pathnode->path.rows += subpath->rows;
1661 
1662  if (pathkeys_contained_in(pathkeys, subpath->pathkeys))
1663  {
1664  /* Subpath is adequately ordered, we won't need to sort it */
1665  input_startup_cost += subpath->startup_cost;
1666  input_total_cost += subpath->total_cost;
1667  }
1668  else
1669  {
1670  /* We'll need to insert a Sort node, so include cost for that */
1671  Path sort_path; /* dummy for result of cost_sort */
1672 
1673  cost_sort(&sort_path,
1674  root,
1675  pathkeys,
1676  subpath->total_cost,
1677  subpath->rows,
1678  subpath->pathtarget->width,
1679  0.0,
1680  work_mem,
1681  -1);
1682  input_startup_cost += sort_path.startup_cost;
1683  input_total_cost += sort_path.total_cost;
1684  }
1685 
1686  cost_gather_merge(pathnode, root, rel, pathnode->path.param_info,
1687  input_startup_cost, input_total_cost, rows);
1688 
1689  return pathnode;
1690 }
1691 
1692 /*
1693  * translate_sub_tlist - get subquery column numbers represented by tlist
1694  *
1695  * The given targetlist usually contains only Vars referencing the given relid.
1696  * Extract their varattnos (ie, the column numbers of the subquery) and return
1697  * as an integer List.
1698  *
1699  * If any of the tlist items is not a simple Var, we cannot determine whether
1700  * the subquery's uniqueness condition (if any) matches ours, so punt and
1701  * return NIL.
1702  */
1703 static List *
1704 translate_sub_tlist(List *tlist, int relid)
1705 {
1706  List *result = NIL;
1707  ListCell *l;
1708 
1709  foreach(l, tlist)
1710  {
1711  Var *var = (Var *) lfirst(l);
1712 
1713  if (!var || !IsA(var, Var) ||
1714  var->varno != relid)
1715  return NIL; /* punt */
1716 
1717  result = lappend_int(result, var->varattno);
1718  }
1719  return result;
1720 }
1721 
1722 /*
1723  * create_gather_path
1724  * Creates a path corresponding to a gather scan, returning the
1725  * pathnode.
1726  *
1727  * 'rows' may optionally be set to override row estimates from other sources.
1728  */
1729 GatherPath *
1731  PathTarget *target, Relids required_outer, double *rows)
1732 {
1733  GatherPath *pathnode = makeNode(GatherPath);
1734 
1735  Assert(subpath->parallel_safe);
1736 
1737  pathnode->path.pathtype = T_Gather;
1738  pathnode->path.parent = rel;
1739  pathnode->path.pathtarget = target;
1740  pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
1741  required_outer);
1742  pathnode->path.parallel_aware = false;
1743  pathnode->path.parallel_safe = false;
1744  pathnode->path.parallel_workers = 0;
1745  pathnode->path.pathkeys = NIL; /* Gather has unordered result */
1746 
1747  pathnode->subpath = subpath;
1748  pathnode->num_workers = subpath->parallel_workers;
1749  pathnode->single_copy = false;
1750 
1751  if (pathnode->num_workers == 0)
1752  {
1753  pathnode->path.pathkeys = subpath->pathkeys;
1754  pathnode->num_workers = 1;
1755  pathnode->single_copy = true;
1756  }
1757 
1758  cost_gather(pathnode, root, rel, pathnode->path.param_info, rows);
1759 
1760  return pathnode;
1761 }
1762 
1763 /*
1764  * create_subqueryscan_path
1765  * Creates a path corresponding to a scan of a subquery,
1766  * returning the pathnode.
1767  */
1770  List *pathkeys, Relids required_outer)
1771 {
1773 
1774  pathnode->path.pathtype = T_SubqueryScan;
1775  pathnode->path.parent = rel;
1776  pathnode->path.pathtarget = rel->reltarget;
1777  pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
1778  required_outer);
1779  pathnode->path.parallel_aware = false;
1780  pathnode->path.parallel_safe = rel->consider_parallel &&
1781  subpath->parallel_safe;
1782  pathnode->path.parallel_workers = subpath->parallel_workers;
1783  pathnode->path.pathkeys = pathkeys;
1784  pathnode->subpath = subpath;
1785 
1786  cost_subqueryscan(pathnode, root, rel, pathnode->path.param_info);
1787 
1788  return pathnode;
1789 }
1790 
1791 /*
1792  * create_functionscan_path
1793  * Creates a path corresponding to a sequential scan of a function,
1794  * returning the pathnode.
1795  */
1796 Path *
1798  List *pathkeys, Relids required_outer)
1799 {
1800  Path *pathnode = makeNode(Path);
1801 
1802  pathnode->pathtype = T_FunctionScan;
1803  pathnode->parent = rel;
1804  pathnode->pathtarget = rel->reltarget;
1805  pathnode->param_info = get_baserel_parampathinfo(root, rel,
1806  required_outer);
1807  pathnode->parallel_aware = false;
1808  pathnode->parallel_safe = rel->consider_parallel;
1809  pathnode->parallel_workers = 0;
1810  pathnode->pathkeys = pathkeys;
1811 
1812  cost_functionscan(pathnode, root, rel, pathnode->param_info);
1813 
1814  return pathnode;
1815 }
1816 
1817 /*
1818  * create_tablefuncscan_path
1819  * Creates a path corresponding to a sequential scan of a table function,
1820  * returning the pathnode.
1821  */
1822 Path *
1824  Relids required_outer)
1825 {
1826  Path *pathnode = makeNode(Path);
1827 
1828  pathnode->pathtype = T_TableFuncScan;
1829  pathnode->parent = rel;
1830  pathnode->pathtarget = rel->reltarget;
1831  pathnode->param_info = get_baserel_parampathinfo(root, rel,
1832  required_outer);
1833  pathnode->parallel_aware = false;
1834  pathnode->parallel_safe = rel->consider_parallel;
1835  pathnode->parallel_workers = 0;
1836  pathnode->pathkeys = NIL; /* result is always unordered */
1837 
1838  cost_tablefuncscan(pathnode, root, rel, pathnode->param_info);
1839 
1840  return pathnode;
1841 }
1842 
1843 /*
1844  * create_valuesscan_path
1845  * Creates a path corresponding to a scan of a VALUES list,
1846  * returning the pathnode.
1847  */
1848 Path *
1850  Relids required_outer)
1851 {
1852  Path *pathnode = makeNode(Path);
1853 
1854  pathnode->pathtype = T_ValuesScan;
1855  pathnode->parent = rel;
1856  pathnode->pathtarget = rel->reltarget;
1857  pathnode->param_info = get_baserel_parampathinfo(root, rel,
1858  required_outer);
1859  pathnode->parallel_aware = false;
1860  pathnode->parallel_safe = rel->consider_parallel;
1861  pathnode->parallel_workers = 0;
1862  pathnode->pathkeys = NIL; /* result is always unordered */
1863 
1864  cost_valuesscan(pathnode, root, rel, pathnode->param_info);
1865 
1866  return pathnode;
1867 }
1868 
1869 /*
1870  * create_ctescan_path
1871  * Creates a path corresponding to a scan of a non-self-reference CTE,
1872  * returning the pathnode.
1873  */
1874 Path *
1875 create_ctescan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
1876 {
1877  Path *pathnode = makeNode(Path);
1878 
1879  pathnode->pathtype = T_CteScan;
1880  pathnode->parent = rel;
1881  pathnode->pathtarget = rel->reltarget;
1882  pathnode->param_info = get_baserel_parampathinfo(root, rel,
1883  required_outer);
1884  pathnode->parallel_aware = false;
1885  pathnode->parallel_safe = rel->consider_parallel;
1886  pathnode->parallel_workers = 0;
1887  pathnode->pathkeys = NIL; /* XXX for now, result is always unordered */
1888 
1889  cost_ctescan(pathnode, root, rel, pathnode->param_info);
1890 
1891  return pathnode;
1892 }
1893 
1894 /*
1895  * create_namedtuplestorescan_path
1896  * Creates a path corresponding to a scan of a named tuplestore, returning
1897  * the pathnode.
1898  */
1899 Path *
1901  Relids required_outer)
1902 {
1903  Path *pathnode = makeNode(Path);
1904 
1905  pathnode->pathtype = T_NamedTuplestoreScan;
1906  pathnode->parent = rel;
1907  pathnode->pathtarget = rel->reltarget;
1908  pathnode->param_info = get_baserel_parampathinfo(root, rel,
1909  required_outer);
1910  pathnode->parallel_aware = false;
1911  pathnode->parallel_safe = rel->consider_parallel;
1912  pathnode->parallel_workers = 0;
1913  pathnode->pathkeys = NIL; /* result is always unordered */
1914 
1915  cost_namedtuplestorescan(pathnode, root, rel, pathnode->param_info);
1916 
1917  return pathnode;
1918 }
1919 
1920 /*
1921  * create_worktablescan_path
1922  * Creates a path corresponding to a scan of a self-reference CTE,
1923  * returning the pathnode.
1924  */
1925 Path *
1927  Relids required_outer)
1928 {
1929  Path *pathnode = makeNode(Path);
1930 
1931  pathnode->pathtype = T_WorkTableScan;
1932  pathnode->parent = rel;
1933  pathnode->pathtarget = rel->reltarget;
1934  pathnode->param_info = get_baserel_parampathinfo(root, rel,
1935  required_outer);
1936  pathnode->parallel_aware = false;
1937  pathnode->parallel_safe = rel->consider_parallel;
1938  pathnode->parallel_workers = 0;
1939  pathnode->pathkeys = NIL; /* result is always unordered */
1940 
1941  /* Cost is the same as for a regular CTE scan */
1942  cost_ctescan(pathnode, root, rel, pathnode->param_info);
1943 
1944  return pathnode;
1945 }
1946 
1947 /*
1948  * create_foreignscan_path
1949  * Creates a path corresponding to a scan of a foreign table, foreign join,
1950  * or foreign upper-relation processing, returning the pathnode.
1951  *
1952  * This function is never called from core Postgres; rather, it's expected
1953  * to be called by the GetForeignPaths, GetForeignJoinPaths, or
1954  * GetForeignUpperPaths function of a foreign data wrapper. We make the FDW
1955  * supply all fields of the path, since we do not have any way to calculate
1956  * them in core. However, there is a usually-sane default for the pathtarget
1957  * (rel->reltarget), so we let a NULL for "target" select that.
1958  */
1959 ForeignPath *
1961  PathTarget *target,
1962  double rows, Cost startup_cost, Cost total_cost,
1963  List *pathkeys,
1964  Relids required_outer,
1965  Path *fdw_outerpath,
1966  List *fdw_private)
1967 {
1968  ForeignPath *pathnode = makeNode(ForeignPath);
1969 
1970  pathnode->path.pathtype = T_ForeignScan;
1971  pathnode->path.parent = rel;
1972  pathnode->path.pathtarget = target ? target : rel->reltarget;
1973  pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
1974  required_outer);
1975  pathnode->path.parallel_aware = false;
1976  pathnode->path.parallel_safe = rel->consider_parallel;
1977  pathnode->path.parallel_workers = 0;
1978  pathnode->path.rows = rows;
1979  pathnode->path.startup_cost = startup_cost;
1980  pathnode->path.total_cost = total_cost;
1981  pathnode->path.pathkeys = pathkeys;
1982 
1983  pathnode->fdw_outerpath = fdw_outerpath;
1984  pathnode->fdw_private = fdw_private;
1985 
1986  return pathnode;
1987 }
1988 
1989 /*
1990  * calc_nestloop_required_outer
1991  * Compute the required_outer set for a nestloop join path
1992  *
1993  * Note: result must not share storage with either input
1994  */
1995 Relids
1997  Relids outer_paramrels,
1998  Relids innerrelids,
1999  Relids inner_paramrels)
2000 {
2001  Relids required_outer;
2002 
2003  /* inner_path can require rels from outer path, but not vice versa */
2004  Assert(!bms_overlap(outer_paramrels, innerrelids));
2005  /* easy case if inner path is not parameterized */
2006  if (!inner_paramrels)
2007  return bms_copy(outer_paramrels);
2008  /* else, form the union ... */
2009  required_outer = bms_union(outer_paramrels, inner_paramrels);
2010  /* ... and remove any mention of now-satisfied outer rels */
2011  required_outer = bms_del_members(required_outer,
2012  outerrelids);
2013  /* maintain invariant that required_outer is exactly NULL if empty */
2014  if (bms_is_empty(required_outer))
2015  {
2016  bms_free(required_outer);
2017  required_outer = NULL;
2018  }
2019  return required_outer;
2020 }
2021 
2022 /*
2023  * calc_non_nestloop_required_outer
2024  * Compute the required_outer set for a merge or hash join path
2025  *
2026  * Note: result must not share storage with either input
2027  */
2028 Relids
2029 calc_non_nestloop_required_outer(Path *outer_path, Path *inner_path)
2030 {
2031  Relids outer_paramrels = PATH_REQ_OUTER(outer_path);
2032  Relids inner_paramrels = PATH_REQ_OUTER(inner_path);
2033  Relids required_outer;
2034 
2035  /* neither path can require rels from the other */
2036  Assert(!bms_overlap(outer_paramrels, inner_path->parent->relids));
2037  Assert(!bms_overlap(inner_paramrels, outer_path->parent->relids));
2038  /* form the union ... */
2039  required_outer = bms_union(outer_paramrels, inner_paramrels);
2040  /* we do not need an explicit test for empty; bms_union gets it right */
2041  return required_outer;
2042 }
2043 
2044 /*
2045  * create_nestloop_path
2046  * Creates a pathnode corresponding to a nestloop join between two
2047  * relations.
2048  *
2049  * 'joinrel' is the join relation.
2050  * 'jointype' is the type of join required
2051  * 'workspace' is the result from initial_cost_nestloop
2052  * 'extra' contains various information about the join
2053  * 'outer_path' is the outer path
2054  * 'inner_path' is the inner path
2055  * 'restrict_clauses' are the RestrictInfo nodes to apply at the join
2056  * 'pathkeys' are the path keys of the new join path
2057  * 'required_outer' is the set of required outer rels
2058  *
2059  * Returns the resulting path node.
2060  */
2061 NestPath *
2063  RelOptInfo *joinrel,
2064  JoinType jointype,
2065  JoinCostWorkspace *workspace,
2066  JoinPathExtraData *extra,
2067  Path *outer_path,
2068  Path *inner_path,
2069  List *restrict_clauses,
2070  List *pathkeys,
2071  Relids required_outer)
2072 {
2073  NestPath *pathnode = makeNode(NestPath);
2074  Relids inner_req_outer = PATH_REQ_OUTER(inner_path);
2075 
2076  /*
2077  * If the inner path is parameterized by the outer, we must drop any
2078  * restrict_clauses that are due to be moved into the inner path. We have
2079  * to do this now, rather than postpone the work till createplan time,
2080  * because the restrict_clauses list can affect the size and cost
2081  * estimates for this path.
2082  */
2083  if (bms_overlap(inner_req_outer, outer_path->parent->relids))
2084  {
2085  Relids inner_and_outer = bms_union(inner_path->parent->relids,
2086  inner_req_outer);
2087  List *jclauses = NIL;
2088  ListCell *lc;
2089 
2090  foreach(lc, restrict_clauses)
2091  {
2092  RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
2093 
2094  if (!join_clause_is_movable_into(rinfo,
2095  inner_path->parent->relids,
2096  inner_and_outer))
2097  jclauses = lappend(jclauses, rinfo);
2098  }
2099  restrict_clauses = jclauses;
2100  }
2101 
2102  pathnode->path.pathtype = T_NestLoop;
2103  pathnode->path.parent = joinrel;
2104  pathnode->path.pathtarget = joinrel->reltarget;
2105  pathnode->path.param_info =
2107  joinrel,
2108  outer_path,
2109  inner_path,
2110  extra->sjinfo,
2111  required_outer,
2112  &restrict_clauses);
2113  pathnode->path.parallel_aware = false;
2114  pathnode->path.parallel_safe = joinrel->consider_parallel &&
2115  outer_path->parallel_safe && inner_path->parallel_safe;
2116  /* This is a foolish way to estimate parallel_workers, but for now... */
2117  pathnode->path.parallel_workers = outer_path->parallel_workers;
2118  pathnode->path.pathkeys = pathkeys;
2119  pathnode->jointype = jointype;
2120  pathnode->inner_unique = extra->inner_unique;
2121  pathnode->outerjoinpath = outer_path;
2122  pathnode->innerjoinpath = inner_path;
2123  pathnode->joinrestrictinfo = restrict_clauses;
2124 
2125  final_cost_nestloop(root, pathnode, workspace, extra);
2126 
2127  return pathnode;
2128 }
2129 
2130 /*
2131  * create_mergejoin_path
2132  * Creates a pathnode corresponding to a mergejoin join between
2133  * two relations
2134  *
2135  * 'joinrel' is the join relation
2136  * 'jointype' is the type of join required
2137  * 'workspace' is the result from initial_cost_mergejoin
2138  * 'extra' contains various information about the join
2139  * 'outer_path' is the outer path
2140  * 'inner_path' is the inner path
2141  * 'restrict_clauses' are the RestrictInfo nodes to apply at the join
2142  * 'pathkeys' are the path keys of the new join path
2143  * 'required_outer' is the set of required outer rels
2144  * 'mergeclauses' are the RestrictInfo nodes to use as merge clauses
2145  * (this should be a subset of the restrict_clauses list)
2146  * 'outersortkeys' are the sort varkeys for the outer relation
2147  * 'innersortkeys' are the sort varkeys for the inner relation
2148  */
2149 MergePath *
2151  RelOptInfo *joinrel,
2152  JoinType jointype,
2153  JoinCostWorkspace *workspace,
2154  JoinPathExtraData *extra,
2155  Path *outer_path,
2156  Path *inner_path,
2157  List *restrict_clauses,
2158  List *pathkeys,
2159  Relids required_outer,
2160  List *mergeclauses,
2161  List *outersortkeys,
2162  List *innersortkeys)
2163 {
2164  MergePath *pathnode = makeNode(MergePath);
2165 
2166  pathnode->jpath.path.pathtype = T_MergeJoin;
2167  pathnode->jpath.path.parent = joinrel;
2168  pathnode->jpath.path.pathtarget = joinrel->reltarget;
2169  pathnode->jpath.path.param_info =
2171  joinrel,
2172  outer_path,
2173  inner_path,
2174  extra->sjinfo,
2175  required_outer,
2176  &restrict_clauses);
2177  pathnode->jpath.path.parallel_aware = false;
2178  pathnode->jpath.path.parallel_safe = joinrel->consider_parallel &&
2179  outer_path->parallel_safe && inner_path->parallel_safe;
2180  /* This is a foolish way to estimate parallel_workers, but for now... */
2181  pathnode->jpath.path.parallel_workers = outer_path->parallel_workers;
2182  pathnode->jpath.path.pathkeys = pathkeys;
2183  pathnode->jpath.jointype = jointype;
2184  pathnode->jpath.inner_unique = extra->inner_unique;
2185  pathnode->jpath.outerjoinpath = outer_path;
2186  pathnode->jpath.innerjoinpath = inner_path;
2187  pathnode->jpath.joinrestrictinfo = restrict_clauses;
2188  pathnode->path_mergeclauses = mergeclauses;
2189  pathnode->outersortkeys = outersortkeys;
2190  pathnode->innersortkeys = innersortkeys;
2191  /* pathnode->skip_mark_restore will be set by final_cost_mergejoin */
2192  /* pathnode->materialize_inner will be set by final_cost_mergejoin */
2193 
2194  final_cost_mergejoin(root, pathnode, workspace, extra);
2195 
2196  return pathnode;
2197 }
2198 
2199 /*
2200  * create_hashjoin_path
2201  * Creates a pathnode corresponding to a hash join between two relations.
2202  *
2203  * 'joinrel' is the join relation
2204  * 'jointype' is the type of join required
2205  * 'workspace' is the result from initial_cost_hashjoin
2206  * 'extra' contains various information about the join
2207  * 'outer_path' is the cheapest outer path
2208  * 'inner_path' is the cheapest inner path
2209  * 'restrict_clauses' are the RestrictInfo nodes to apply at the join
2210  * 'required_outer' is the set of required outer rels
2211  * 'hashclauses' are the RestrictInfo nodes to use as hash clauses
2212  * (this should be a subset of the restrict_clauses list)
2213  */
2214 HashPath *
2216  RelOptInfo *joinrel,
2217  JoinType jointype,
2218  JoinCostWorkspace *workspace,
2219  JoinPathExtraData *extra,
2220  Path *outer_path,
2221  Path *inner_path,
2222  List *restrict_clauses,
2223  Relids required_outer,
2224  List *hashclauses)
2225 {
2226  HashPath *pathnode = makeNode(HashPath);
2227 
2228  pathnode->jpath.path.pathtype = T_HashJoin;
2229  pathnode->jpath.path.parent = joinrel;
2230  pathnode->jpath.path.pathtarget = joinrel->reltarget;
2231  pathnode->jpath.path.param_info =
2233  joinrel,
2234  outer_path,
2235  inner_path,
2236  extra->sjinfo,
2237  required_outer,
2238  &restrict_clauses);
2239  pathnode->jpath.path.parallel_aware = false;
2240  pathnode->jpath.path.parallel_safe = joinrel->consider_parallel &&
2241  outer_path->parallel_safe && inner_path->parallel_safe;
2242  /* This is a foolish way to estimate parallel_workers, but for now... */
2243  pathnode->jpath.path.parallel_workers = outer_path->parallel_workers;
2244 
2245  /*
2246  * A hashjoin never has pathkeys, since its output ordering is
2247  * unpredictable due to possible batching. XXX If the inner relation is
2248  * small enough, we could instruct the executor that it must not batch,
2249  * and then we could assume that the output inherits the outer relation's
2250  * ordering, which might save a sort step. However there is considerable
2251  * downside if our estimate of the inner relation size is badly off. For
2252  * the moment we don't risk it. (Note also that if we wanted to take this
2253  * seriously, joinpath.c would have to consider many more paths for the
2254  * outer rel than it does now.)
2255  */
2256  pathnode->jpath.path.pathkeys = NIL;
2257  pathnode->jpath.jointype = jointype;
2258  pathnode->jpath.inner_unique = extra->inner_unique;
2259  pathnode->jpath.outerjoinpath = outer_path;
2260  pathnode->jpath.innerjoinpath = inner_path;
2261  pathnode->jpath.joinrestrictinfo = restrict_clauses;
2262  pathnode->path_hashclauses = hashclauses;
2263  /* final_cost_hashjoin will fill in pathnode->num_batches */
2264 
2265  final_cost_hashjoin(root, pathnode, workspace, extra);
2266 
2267  return pathnode;
2268 }
2269 
2270 /*
2271  * create_projection_path
2272  * Creates a pathnode that represents performing a projection.
2273  *
2274  * 'rel' is the parent relation associated with the result
2275  * 'subpath' is the path representing the source of data
2276  * 'target' is the PathTarget to be computed
2277  */
2280  RelOptInfo *rel,
2281  Path *subpath,
2282  PathTarget *target)
2283 {
2284  ProjectionPath *pathnode = makeNode(ProjectionPath);
2285  PathTarget *oldtarget = subpath->pathtarget;
2286 
2287  pathnode->path.pathtype = T_Result;
2288  pathnode->path.parent = rel;
2289  pathnode->path.pathtarget = target;
2290  /* For now, assume we are above any joins, so no parameterization */
2291  pathnode->path.param_info = NULL;
2292  pathnode->path.parallel_aware = false;
2293  pathnode->path.parallel_safe = rel->consider_parallel &&
2294  subpath->parallel_safe &&
2295  is_parallel_safe(root, (Node *) target->exprs);
2296  pathnode->path.parallel_workers = subpath->parallel_workers;
2297  /* Projection does not change the sort order */
2298  pathnode->path.pathkeys = subpath->pathkeys;
2299 
2300  pathnode->subpath = subpath;
2301 
2302  /*
2303  * We might not need a separate Result node. If the input plan node type
2304  * can project, we can just tell it to project something else. Or, if it
2305  * can't project but the desired target has the same expression list as
2306  * what the input will produce anyway, we can still give it the desired
2307  * tlist (possibly changing its ressortgroupref labels, but nothing else).
2308  * Note: in the latter case, create_projection_plan has to recheck our
2309  * conclusion; see comments therein.
2310  */
2311  if (is_projection_capable_path(subpath) ||
2312  equal(oldtarget->exprs, target->exprs))
2313  {
2314  /* No separate Result node needed */
2315  pathnode->dummypp = true;
2316 
2317  /*
2318  * Set cost of plan as subpath's cost, adjusted for tlist replacement.
2319  */
2320  pathnode->path.rows = subpath->rows;
2321  pathnode->path.startup_cost = subpath->startup_cost +
2322  (target->cost.startup - oldtarget->cost.startup);
2323  pathnode->path.total_cost = subpath->total_cost +
2324  (target->cost.startup - oldtarget->cost.startup) +
2325  (target->cost.per_tuple - oldtarget->cost.per_tuple) * subpath->rows;
2326  }
2327  else
2328  {
2329  /* We really do need the Result node */
2330  pathnode->dummypp = false;
2331 
2332  /*
2333  * The Result node's cost is cpu_tuple_cost per row, plus the cost of
2334  * evaluating the tlist. There is no qual to worry about.
2335  */
2336  pathnode->path.rows = subpath->rows;
2337  pathnode->path.startup_cost = subpath->startup_cost +
2338  target->cost.startup;
2339  pathnode->path.total_cost = subpath->total_cost +
2340  target->cost.startup +
2341  (cpu_tuple_cost + target->cost.per_tuple) * subpath->rows;
2342  }
2343 
2344  return pathnode;
2345 }
2346 
2347 /*
2348  * apply_projection_to_path
2349  * Add a projection step, or just apply the target directly to given path.
2350  *
2351  * This has the same net effect as create_projection_path(), except that if
2352  * a separate Result plan node isn't needed, we just replace the given path's
2353  * pathtarget with the desired one. This must be used only when the caller
2354  * knows that the given path isn't referenced elsewhere and so can be modified
2355  * in-place.
2356  *
2357  * If the input path is a GatherPath, we try to push the new target down to
2358  * its input as well; this is a yet more invasive modification of the input
2359  * path, which create_projection_path() can't do.
2360  *
2361  * Note that we mustn't change the source path's parent link; so when it is
2362  * add_path'd to "rel" things will be a bit inconsistent. So far that has
2363  * not caused any trouble.
2364  *
2365  * 'rel' is the parent relation associated with the result
2366  * 'path' is the path representing the source of data
2367  * 'target' is the PathTarget to be computed
2368  */
2369 Path *
2371  RelOptInfo *rel,
2372  Path *path,
2373  PathTarget *target)
2374 {
2375  QualCost oldcost;
2376 
2377  /*
2378  * If given path can't project, we might need a Result node, so make a
2379  * separate ProjectionPath.
2380  */
2381  if (!is_projection_capable_path(path))
2382  return (Path *) create_projection_path(root, rel, path, target);
2383 
2384  /*
2385  * We can just jam the desired tlist into the existing path, being sure to
2386  * update its cost estimates appropriately.
2387  */
2388  oldcost = path->pathtarget->cost;
2389  path->pathtarget = target;
2390 
2391  path->startup_cost += target->cost.startup - oldcost.startup;
2392  path->total_cost += target->cost.startup - oldcost.startup +
2393  (target->cost.per_tuple - oldcost.per_tuple) * path->rows;
2394 
2395  /*
2396  * If the path happens to be a Gather path, we'd like to arrange for the
2397  * subpath to return the required target list so that workers can help
2398  * project. But if there is something that is not parallel-safe in the
2399  * target expressions, then we can't.
2400  */
2401  if (IsA(path, GatherPath) &&
2402  is_parallel_safe(root, (Node *) target->exprs))
2403  {
2404  GatherPath *gpath = (GatherPath *) path;
2405 
2406  /*
2407  * We always use create_projection_path here, even if the subpath is
2408  * projection-capable, so as to avoid modifying the subpath in place.
2409  * It seems unlikely at present that there could be any other
2410  * references to the subpath, but better safe than sorry.
2411  *
2412  * Note that we don't change the GatherPath's cost estimates; it might
2413  * be appropriate to do so, to reflect the fact that the bulk of the
2414  * target evaluation will happen in workers.
2415  */
2416  gpath->subpath = (Path *)
2418  gpath->subpath->parent,
2419  gpath->subpath,
2420  target);
2421  }
2422  else if (path->parallel_safe &&
2423  !is_parallel_safe(root, (Node *) target->exprs))
2424  {
2425  /*
2426  * We're inserting a parallel-restricted target list into a path
2427  * currently marked parallel-safe, so we have to mark it as no longer
2428  * safe.
2429  */
2430  path->parallel_safe = false;
2431  }
2432 
2433  return path;
2434 }
2435 
2436 /*
2437  * create_set_projection_path
2438  * Creates a pathnode that represents performing a projection that
2439  * includes set-returning functions.
2440  *
2441  * 'rel' is the parent relation associated with the result
2442  * 'subpath' is the path representing the source of data
2443  * 'target' is the PathTarget to be computed
2444  */
2447  RelOptInfo *rel,
2448  Path *subpath,
2449  PathTarget *target)
2450 {
2451  ProjectSetPath *pathnode = makeNode(ProjectSetPath);
2452  double tlist_rows;
2453  ListCell *lc;
2454 
2455  pathnode->path.pathtype = T_ProjectSet;
2456  pathnode->path.parent = rel;
2457  pathnode->path.pathtarget = target;
2458  /* For now, assume we are above any joins, so no parameterization */
2459  pathnode->path.param_info = NULL;
2460  pathnode->path.parallel_aware = false;
2461  pathnode->path.parallel_safe = rel->consider_parallel &&
2462  subpath->parallel_safe &&
2463  is_parallel_safe(root, (Node *) target->exprs);
2464  pathnode->path.parallel_workers = subpath->parallel_workers;
2465  /* Projection does not change the sort order XXX? */
2466  pathnode->path.pathkeys = subpath->pathkeys;
2467 
2468  pathnode->subpath = subpath;
2469 
2470  /*
2471  * Estimate number of rows produced by SRFs for each row of input; if
2472  * there's more than one in this node, use the maximum.
2473  */
2474  tlist_rows = 1;
2475  foreach(lc, target->exprs)
2476  {
2477  Node *node = (Node *) lfirst(lc);
2478  double itemrows;
2479 
2480  itemrows = expression_returns_set_rows(node);
2481  if (tlist_rows < itemrows)
2482  tlist_rows = itemrows;
2483  }
2484 
2485  /*
2486  * In addition to the cost of evaluating the tlist, charge cpu_tuple_cost
2487  * per input row, and half of cpu_tuple_cost for each added output row.
2488  * This is slightly bizarre maybe, but it's what 9.6 did; we may revisit
2489  * this estimate later.
2490  */
2491  pathnode->path.rows = subpath->rows * tlist_rows;
2492  pathnode->path.startup_cost = subpath->startup_cost +
2493  target->cost.startup;
2494  pathnode->path.total_cost = subpath->total_cost +
2495  target->cost.startup +
2496  (cpu_tuple_cost + target->cost.per_tuple) * subpath->rows +
2497  (pathnode->path.rows - subpath->rows) * cpu_tuple_cost / 2;
2498 
2499  return pathnode;
2500 }
2501 
2502 /*
2503  * create_sort_path
2504  * Creates a pathnode that represents performing an explicit sort.
2505  *
2506  * 'rel' is the parent relation associated with the result
2507  * 'subpath' is the path representing the source of data
2508  * 'pathkeys' represents the desired sort order
2509  * 'limit_tuples' is the estimated bound on the number of output tuples,
2510  * or -1 if no LIMIT or couldn't estimate
2511  */
2512 SortPath *
2514  RelOptInfo *rel,
2515  Path *subpath,
2516  List *pathkeys,
2517  double limit_tuples)
2518 {
2519  SortPath *pathnode = makeNode(SortPath);
2520 
2521  pathnode->path.pathtype = T_Sort;
2522  pathnode->path.parent = rel;
2523  /* Sort doesn't project, so use source path's pathtarget */
2524  pathnode->path.pathtarget = subpath->pathtarget;
2525  /* For now, assume we are above any joins, so no parameterization */
2526  pathnode->path.param_info = NULL;
2527  pathnode->path.parallel_aware = false;
2528  pathnode->path.parallel_safe = rel->consider_parallel &&
2529  subpath->parallel_safe;
2530  pathnode->path.parallel_workers = subpath->parallel_workers;
2531  pathnode->path.pathkeys = pathkeys;
2532 
2533  pathnode->subpath = subpath;
2534 
2535  cost_sort(&pathnode->path, root, pathkeys,
2536  subpath->total_cost,
2537  subpath->rows,
2538  subpath->pathtarget->width,
2539  0.0, /* XXX comparison_cost shouldn't be 0? */
2540  work_mem, limit_tuples);
2541 
2542  return pathnode;
2543 }
2544 
2545 /*
2546  * create_group_path
2547  * Creates a pathnode that represents performing grouping of presorted input
2548  *
2549  * 'rel' is the parent relation associated with the result
2550  * 'subpath' is the path representing the source of data
2551  * 'target' is the PathTarget to be computed
2552  * 'groupClause' is a list of SortGroupClause's representing the grouping
2553  * 'qual' is the HAVING quals if any
2554  * 'numGroups' is the estimated number of groups
2555  */
2556 GroupPath *
2558  RelOptInfo *rel,
2559  Path *subpath,
2560  PathTarget *target,
2561  List *groupClause,
2562  List *qual,
2563  double numGroups)
2564 {
2565  GroupPath *pathnode = makeNode(GroupPath);
2566 
2567  pathnode->path.pathtype = T_Group;
2568  pathnode->path.parent = rel;
2569  pathnode->path.pathtarget = target;
2570  /* For now, assume we are above any joins, so no parameterization */
2571  pathnode->path.param_info = NULL;
2572  pathnode->path.parallel_aware = false;
2573  pathnode->path.parallel_safe = rel->consider_parallel &&
2574  subpath->parallel_safe;
2575  pathnode->path.parallel_workers = subpath->parallel_workers;
2576  /* Group doesn't change sort ordering */
2577  pathnode->path.pathkeys = subpath->pathkeys;
2578 
2579  pathnode->subpath = subpath;
2580 
2581  pathnode->groupClause = groupClause;
2582  pathnode->qual = qual;
2583 
2584  cost_group(&pathnode->path, root,
2585  list_length(groupClause),
2586  numGroups,
2587  subpath->startup_cost, subpath->total_cost,
2588  subpath->rows);
2589 
2590  /* add tlist eval cost for each output row */
2591  pathnode->path.startup_cost += target->cost.startup;
2592  pathnode->path.total_cost += target->cost.startup +
2593  target->cost.per_tuple * pathnode->path.rows;
2594 
2595  return pathnode;
2596 }
2597 
2598 /*
2599  * create_upper_unique_path
2600  * Creates a pathnode that represents performing an explicit Unique step
2601  * on presorted input.
2602  *
2603  * This produces a Unique plan node, but the use-case is so different from
2604  * create_unique_path that it doesn't seem worth trying to merge the two.
2605  *
2606  * 'rel' is the parent relation associated with the result
2607  * 'subpath' is the path representing the source of data
2608  * 'numCols' is the number of grouping columns
2609  * 'numGroups' is the estimated number of groups
2610  *
2611  * The input path must be sorted on the grouping columns, plus possibly
2612  * additional columns; so the first numCols pathkeys are the grouping columns
2613  */
2616  RelOptInfo *rel,
2617  Path *subpath,
2618  int numCols,
2619  double numGroups)
2620 {
2622 
2623  pathnode->path.pathtype = T_Unique;
2624  pathnode->path.parent = rel;
2625  /* Unique doesn't project, so use source path's pathtarget */
2626  pathnode->path.pathtarget = subpath->pathtarget;
2627  /* For now, assume we are above any joins, so no parameterization */
2628  pathnode->path.param_info = NULL;
2629  pathnode->path.parallel_aware = false;
2630  pathnode->path.parallel_safe = rel->consider_parallel &&
2631  subpath->parallel_safe;
2632  pathnode->path.parallel_workers = subpath->parallel_workers;
2633  /* Unique doesn't change the input ordering */
2634  pathnode->path.pathkeys = subpath->pathkeys;
2635 
2636  pathnode->subpath = subpath;
2637  pathnode->numkeys = numCols;
2638 
2639  /*
2640  * Charge one cpu_operator_cost per comparison per input tuple. We assume
2641  * all columns get compared at most of the tuples. (XXX probably this is
2642  * an overestimate.)
2643  */
2644  pathnode->path.startup_cost = subpath->startup_cost;
2645  pathnode->path.total_cost = subpath->total_cost +
2646  cpu_operator_cost * subpath->rows * numCols;
2647  pathnode->path.rows = numGroups;
2648 
2649  return pathnode;
2650 }
2651 
2652 /*
2653  * create_agg_path
2654  * Creates a pathnode that represents performing aggregation/grouping
2655  *
2656  * 'rel' is the parent relation associated with the result
2657  * 'subpath' is the path representing the source of data
2658  * 'target' is the PathTarget to be computed
2659  * 'aggstrategy' is the Agg node's basic implementation strategy
2660  * 'aggsplit' is the Agg node's aggregate-splitting mode
2661  * 'groupClause' is a list of SortGroupClause's representing the grouping
2662  * 'qual' is the HAVING quals if any
2663  * 'aggcosts' contains cost info about the aggregate functions to be computed
2664  * 'numGroups' is the estimated number of groups (1 if not grouping)
2665  */
2666 AggPath *
2668  RelOptInfo *rel,
2669  Path *subpath,
2670  PathTarget *target,
2671  AggStrategy aggstrategy,
2672  AggSplit aggsplit,
2673  List *groupClause,
2674  List *qual,
2675  const AggClauseCosts *aggcosts,
2676  double numGroups)
2677 {
2678  AggPath *pathnode = makeNode(AggPath);
2679 
2680  pathnode->path.pathtype = T_Agg;
2681  pathnode->path.parent = rel;
2682  pathnode->path.pathtarget = target;
2683  /* For now, assume we are above any joins, so no parameterization */
2684  pathnode->path.param_info = NULL;
2685  pathnode->path.parallel_aware = false;
2686  pathnode->path.parallel_safe = rel->consider_parallel &&
2687  subpath->parallel_safe;
2688  pathnode->path.parallel_workers = subpath->parallel_workers;
2689  if (aggstrategy == AGG_SORTED)
2690  pathnode->path.pathkeys = subpath->pathkeys; /* preserves order */
2691  else
2692  pathnode->path.pathkeys = NIL; /* output is unordered */
2693  pathnode->subpath = subpath;
2694 
2695  pathnode->aggstrategy = aggstrategy;
2696  pathnode->aggsplit = aggsplit;
2697  pathnode->numGroups = numGroups;
2698  pathnode->groupClause = groupClause;
2699  pathnode->qual = qual;
2700 
2701  cost_agg(&pathnode->path, root,
2702  aggstrategy, aggcosts,
2703  list_length(groupClause), numGroups,
2704  subpath->startup_cost, subpath->total_cost,
2705  subpath->rows);
2706 
2707  /* add tlist eval cost for each output row */
2708  pathnode->path.startup_cost += target->cost.startup;
2709  pathnode->path.total_cost += target->cost.startup +
2710  target->cost.per_tuple * pathnode->path.rows;
2711 
2712  return pathnode;
2713 }
2714 
2715 /*
2716  * create_groupingsets_path
2717  * Creates a pathnode that represents performing GROUPING SETS aggregation
2718  *
2719  * GroupingSetsPath represents sorted grouping with one or more grouping sets.
2720  * The input path's result must be sorted to match the last entry in
2721  * rollup_groupclauses.
2722  *
2723  * 'rel' is the parent relation associated with the result
2724  * 'subpath' is the path representing the source of data
2725  * 'target' is the PathTarget to be computed
2726  * 'having_qual' is the HAVING quals if any
2727  * 'rollups' is a list of RollupData nodes
2728  * 'agg_costs' contains cost info about the aggregate functions to be computed
2729  * 'numGroups' is the estimated total number of groups
2730  */
2733  RelOptInfo *rel,
2734  Path *subpath,
2735  PathTarget *target,
2736  List *having_qual,
2737  AggStrategy aggstrategy,
2738  List *rollups,
2739  const AggClauseCosts *agg_costs,
2740  double numGroups)
2741 {
2743  ListCell *lc;
2744  bool is_first = true;
2745  bool is_first_sort = true;
2746 
2747  /* The topmost generated Plan node will be an Agg */
2748  pathnode->path.pathtype = T_Agg;
2749  pathnode->path.parent = rel;
2750  pathnode->path.pathtarget = target;
2751  pathnode->path.param_info = subpath->param_info;
2752  pathnode->path.parallel_aware = false;
2753  pathnode->path.parallel_safe = rel->consider_parallel &&
2754  subpath->parallel_safe;
2755  pathnode->path.parallel_workers = subpath->parallel_workers;
2756  pathnode->subpath = subpath;
2757 
2758  /*
2759  * Simplify callers by downgrading AGG_SORTED to AGG_PLAIN, and AGG_MIXED
2760  * to AGG_HASHED, here if possible.
2761  */
2762  if (aggstrategy == AGG_SORTED &&
2763  list_length(rollups) == 1 &&
2764  ((RollupData *) linitial(rollups))->groupClause == NIL)
2765  aggstrategy = AGG_PLAIN;
2766 
2767  if (aggstrategy == AGG_MIXED &&
2768  list_length(rollups) == 1)
2769  aggstrategy = AGG_HASHED;
2770 
2771  /*
2772  * Output will be in sorted order by group_pathkeys if, and only if, there
2773  * is a single rollup operation on a non-empty list of grouping
2774  * expressions.
2775  */
2776  if (aggstrategy == AGG_SORTED && list_length(rollups) == 1)
2777  pathnode->path.pathkeys = root->group_pathkeys;
2778  else
2779  pathnode->path.pathkeys = NIL;
2780 
2781  pathnode->aggstrategy = aggstrategy;
2782  pathnode->rollups = rollups;
2783  pathnode->qual = having_qual;
2784 
2785  Assert(rollups != NIL);
2786  Assert(aggstrategy != AGG_PLAIN || list_length(rollups) == 1);
2787  Assert(aggstrategy != AGG_MIXED || list_length(rollups) > 1);
2788 
2789  foreach(lc, rollups)
2790  {
2791  RollupData *rollup = lfirst(lc);
2792  List *gsets = rollup->gsets;
2793  int numGroupCols = list_length(linitial(gsets));
2794 
2795  /*
2796  * In AGG_SORTED or AGG_PLAIN mode, the first rollup takes the
2797  * (already-sorted) input, and following ones do their own sort.
2798  *
2799  * In AGG_HASHED mode, there is one rollup for each grouping set.
2800  *
2801  * In AGG_MIXED mode, the first rollups are hashed, the first
2802  * non-hashed one takes the (already-sorted) input, and following ones
2803  * do their own sort.
2804  */
2805  if (is_first)
2806  {
2807  cost_agg(&pathnode->path, root,
2808  aggstrategy,
2809  agg_costs,
2810  numGroupCols,
2811  rollup->numGroups,
2812  subpath->startup_cost,
2813  subpath->total_cost,
2814  subpath->rows);
2815  is_first = false;
2816  if (!rollup->is_hashed)
2817  is_first_sort = false;
2818  }
2819  else
2820  {
2821  Path sort_path; /* dummy for result of cost_sort */
2822  Path agg_path; /* dummy for result of cost_agg */
2823 
2824  if (rollup->is_hashed || is_first_sort)
2825  {
2826  /*
2827  * Account for cost of aggregation, but don't charge input
2828  * cost again
2829  */
2830  cost_agg(&agg_path, root,
2831  rollup->is_hashed ? AGG_HASHED : AGG_SORTED,
2832  agg_costs,
2833  numGroupCols,
2834  rollup->numGroups,
2835  0.0, 0.0,
2836  subpath->rows);
2837  if (!rollup->is_hashed)
2838  is_first_sort = false;
2839  }
2840  else
2841  {
2842  /* Account for cost of sort, but don't charge input cost again */
2843  cost_sort(&sort_path, root, NIL,
2844  0.0,
2845  subpath->rows,
2846  subpath->pathtarget->width,
2847  0.0,
2848  work_mem,
2849  -1.0);
2850 
2851  /* Account for cost of aggregation */
2852 
2853  cost_agg(&agg_path, root,
2854  AGG_SORTED,
2855  agg_costs,
2856  numGroupCols,
2857  rollup->numGroups,
2858  sort_path.startup_cost,
2859  sort_path.total_cost,
2860  sort_path.rows);
2861  }
2862 
2863  pathnode->path.total_cost += agg_path.total_cost;
2864  pathnode->path.rows += agg_path.rows;
2865  }
2866  }
2867 
2868  /* add tlist eval cost for each output row */
2869  pathnode->path.startup_cost += target->cost.startup;
2870  pathnode->path.total_cost += target->cost.startup +
2871  target->cost.per_tuple * pathnode->path.rows;
2872 
2873  return pathnode;
2874 }
2875 
2876 /*
2877  * create_minmaxagg_path
2878  * Creates a pathnode that represents computation of MIN/MAX aggregates
2879  *
2880  * 'rel' is the parent relation associated with the result
2881  * 'target' is the PathTarget to be computed
2882  * 'mmaggregates' is a list of MinMaxAggInfo structs
2883  * 'quals' is the HAVING quals if any
2884  */
2885 MinMaxAggPath *
2887  RelOptInfo *rel,
2888  PathTarget *target,
2889  List *mmaggregates,
2890  List *quals)
2891 {
2892  MinMaxAggPath *pathnode = makeNode(MinMaxAggPath);
2893  Cost initplan_cost;
2894  ListCell *lc;
2895 
2896  /* The topmost generated Plan node will be a Result */
2897  pathnode->path.pathtype = T_Result;
2898  pathnode->path.parent = rel;
2899  pathnode->path.pathtarget = target;
2900  /* For now, assume we are above any joins, so no parameterization */
2901  pathnode->path.param_info = NULL;
2902  pathnode->path.parallel_aware = false;
2903  /* A MinMaxAggPath implies use of subplans, so cannot be parallel-safe */
2904  pathnode->path.parallel_safe = false;
2905  pathnode->path.parallel_workers = 0;
2906  /* Result is one unordered row */
2907  pathnode->path.rows = 1;
2908  pathnode->path.pathkeys = NIL;
2909 
2910  pathnode->mmaggregates = mmaggregates;
2911  pathnode->quals = quals;
2912 
2913  /* Calculate cost of all the initplans ... */
2914  initplan_cost = 0;
2915  foreach(lc, mmaggregates)
2916  {
2917  MinMaxAggInfo *mminfo = (MinMaxAggInfo *) lfirst(lc);
2918 
2919  initplan_cost += mminfo->pathcost;
2920  }
2921 
2922  /* add tlist eval cost for each output row, plus cpu_tuple_cost */
2923  pathnode->path.startup_cost = initplan_cost + target->cost.startup;
2924  pathnode->path.total_cost = initplan_cost + target->cost.startup +
2925  target->cost.per_tuple + cpu_tuple_cost;
2926 
2927  return pathnode;
2928 }
2929 
2930 /*
2931  * create_windowagg_path
2932  * Creates a pathnode that represents computation of window functions
2933  *
2934  * 'rel' is the parent relation associated with the result
2935  * 'subpath' is the path representing the source of data
2936  * 'target' is the PathTarget to be computed
2937  * 'windowFuncs' is a list of WindowFunc structs
2938  * 'winclause' is a WindowClause that is common to all the WindowFuncs
2939  * 'winpathkeys' is the pathkeys for the PARTITION keys + ORDER keys
2940  *
2941  * The actual sort order of the input must match winpathkeys, but might
2942  * have additional keys after those.
2943  */
2944 WindowAggPath *
2946  RelOptInfo *rel,
2947  Path *subpath,
2948  PathTarget *target,
2949  List *windowFuncs,
2950  WindowClause *winclause,
2951  List *winpathkeys)
2952 {
2953  WindowAggPath *pathnode = makeNode(WindowAggPath);
2954 
2955  pathnode->path.pathtype = T_WindowAgg;
2956  pathnode->path.parent = rel;
2957  pathnode->path.pathtarget = target;
2958  /* For now, assume we are above any joins, so no parameterization */
2959  pathnode->path.param_info = NULL;
2960  pathnode->path.parallel_aware = false;
2961  pathnode->path.parallel_safe = rel->consider_parallel &&
2962  subpath->parallel_safe;
2963  pathnode->path.parallel_workers = subpath->parallel_workers;
2964  /* WindowAgg preserves the input sort order */
2965  pathnode->path.pathkeys = subpath->pathkeys;
2966 
2967  pathnode->subpath = subpath;
2968  pathnode->winclause = winclause;
2969  pathnode->winpathkeys = winpathkeys;
2970 
2971  /*
2972  * For costing purposes, assume that there are no redundant partitioning
2973  * or ordering columns; it's not worth the trouble to deal with that
2974  * corner case here. So we just pass the unmodified list lengths to
2975  * cost_windowagg.
2976  */
2977  cost_windowagg(&pathnode->path, root,
2978  windowFuncs,
2979  list_length(winclause->partitionClause),
2980  list_length(winclause->orderClause),
2981  subpath->startup_cost,
2982  subpath->total_cost,
2983  subpath->rows);
2984 
2985  /* add tlist eval cost for each output row */
2986  pathnode->path.startup_cost += target->cost.startup;
2987  pathnode->path.total_cost += target->cost.startup +
2988  target->cost.per_tuple * pathnode->path.rows;
2989 
2990  return pathnode;
2991 }
2992 
2993 /*
2994  * create_setop_path
2995  * Creates a pathnode that represents computation of INTERSECT or EXCEPT
2996  *
2997  * 'rel' is the parent relation associated with the result
2998  * 'subpath' is the path representing the source of data
2999  * 'cmd' is the specific semantics (INTERSECT or EXCEPT, with/without ALL)
3000  * 'strategy' is the implementation strategy (sorted or hashed)
3001  * 'distinctList' is a list of SortGroupClause's representing the grouping
3002  * 'flagColIdx' is the column number where the flag column will be, if any
3003  * 'firstFlag' is the flag value for the first input relation when hashing;
3004  * or -1 when sorting
3005  * 'numGroups' is the estimated number of distinct groups
3006  * 'outputRows' is the estimated number of output rows
3007  */
3008 SetOpPath *
3010  RelOptInfo *rel,
3011  Path *subpath,
3012  SetOpCmd cmd,
3013  SetOpStrategy strategy,
3014  List *distinctList,
3015  AttrNumber flagColIdx,
3016  int firstFlag,
3017  double numGroups,
3018  double outputRows)
3019 {
3020  SetOpPath *pathnode = makeNode(SetOpPath);
3021 
3022  pathnode->path.pathtype = T_SetOp;
3023  pathnode->path.parent = rel;
3024  /* SetOp doesn't project, so use source path's pathtarget */
3025  pathnode->path.pathtarget = subpath->pathtarget;
3026  /* For now, assume we are above any joins, so no parameterization */
3027  pathnode->path.param_info = NULL;
3028  pathnode->path.parallel_aware = false;
3029  pathnode->path.parallel_safe = rel->consider_parallel &&
3030  subpath->parallel_safe;
3031  pathnode->path.parallel_workers = subpath->parallel_workers;
3032  /* SetOp preserves the input sort order if in sort mode */
3033  pathnode->path.pathkeys =
3034  (strategy == SETOP_SORTED) ? subpath->pathkeys : NIL;
3035 
3036  pathnode->subpath = subpath;
3037  pathnode->cmd = cmd;
3038  pathnode->strategy = strategy;
3039  pathnode->distinctList = distinctList;
3040  pathnode->flagColIdx = flagColIdx;
3041  pathnode->firstFlag = firstFlag;
3042  pathnode->numGroups = numGroups;
3043 
3044  /*
3045  * Charge one cpu_operator_cost per comparison per input tuple. We assume
3046  * all columns get compared at most of the tuples.
3047  */
3048  pathnode->path.startup_cost = subpath->startup_cost;
3049  pathnode->path.total_cost = subpath->total_cost +
3050  cpu_operator_cost * subpath->rows * list_length(distinctList);
3051  pathnode->path.rows = outputRows;
3052 
3053  return pathnode;
3054 }
3055 
3056 /*
3057  * create_recursiveunion_path
3058  * Creates a pathnode that represents a recursive UNION node
3059  *
3060  * 'rel' is the parent relation associated with the result
3061  * 'leftpath' is the source of data for the non-recursive term
3062  * 'rightpath' is the source of data for the recursive term
3063  * 'target' is the PathTarget to be computed
3064  * 'distinctList' is a list of SortGroupClause's representing the grouping
3065  * 'wtParam' is the ID of Param representing work table
3066  * 'numGroups' is the estimated number of groups
3067  *
3068  * For recursive UNION ALL, distinctList is empty and numGroups is zero
3069  */
3072  RelOptInfo *rel,
3073  Path *leftpath,
3074  Path *rightpath,
3075  PathTarget *target,
3076  List *distinctList,
3077  int wtParam,
3078  double numGroups)
3079 {
3081 
3082  pathnode->path.pathtype = T_RecursiveUnion;
3083  pathnode->path.parent = rel;
3084  pathnode->path.pathtarget = target;
3085  /* For now, assume we are above any joins, so no parameterization */
3086  pathnode->path.param_info = NULL;
3087  pathnode->path.parallel_aware = false;
3088  pathnode->path.parallel_safe = rel->consider_parallel &&
3089  leftpath->parallel_safe && rightpath->parallel_safe;
3090  /* Foolish, but we'll do it like joins for now: */
3091  pathnode->path.parallel_workers = leftpath->parallel_workers;
3092  /* RecursiveUnion result is always unsorted */
3093  pathnode->path.pathkeys = NIL;
3094 
3095  pathnode->leftpath = leftpath;
3096  pathnode->rightpath = rightpath;
3097  pathnode->distinctList = distinctList;
3098  pathnode->wtParam = wtParam;
3099  pathnode->numGroups = numGroups;
3100 
3101  cost_recursive_union(&pathnode->path, leftpath, rightpath);
3102 
3103  return pathnode;
3104 }
3105 
3106 /*
3107  * create_lockrows_path
3108  * Creates a pathnode that represents acquiring row locks
3109  *
3110  * 'rel' is the parent relation associated with the result
3111  * 'subpath' is the path representing the source of data
3112  * 'rowMarks' is a list of PlanRowMark's
3113  * 'epqParam' is the ID of Param for EvalPlanQual re-eval
3114  */
3115 LockRowsPath *
3117  Path *subpath, List *rowMarks, int epqParam)
3118 {
3119  LockRowsPath *pathnode = makeNode(LockRowsPath);
3120 
3121  pathnode->path.pathtype = T_LockRows;
3122  pathnode->path.parent = rel;
3123  /* LockRows doesn't project, so use source path's pathtarget */
3124  pathnode->path.pathtarget = subpath->pathtarget;
3125  /* For now, assume we are above any joins, so no parameterization */
3126  pathnode->path.param_info = NULL;
3127  pathnode->path.parallel_aware = false;
3128  pathnode->path.parallel_safe = false;
3129  pathnode->path.parallel_workers = 0;
3130  pathnode->path.rows = subpath->rows;
3131 
3132  /*
3133  * The result cannot be assumed sorted, since locking might cause the sort
3134  * key columns to be replaced with new values.
3135  */
3136  pathnode->path.pathkeys = NIL;
3137 
3138  pathnode->subpath = subpath;
3139  pathnode->rowMarks = rowMarks;
3140  pathnode->epqParam = epqParam;
3141 
3142  /*
3143  * We should charge something extra for the costs of row locking and
3144  * possible refetches, but it's hard to say how much. For now, use
3145  * cpu_tuple_cost per row.
3146  */
3147  pathnode->path.startup_cost = subpath->startup_cost;
3148  pathnode->path.total_cost = subpath->total_cost +
3149  cpu_tuple_cost * subpath->rows;
3150 
3151  return pathnode;
3152 }
3153 
3154 /*
3155  * create_modifytable_path
3156  * Creates a pathnode that represents performing INSERT/UPDATE/DELETE mods
3157  *
3158  * 'rel' is the parent relation associated with the result
3159  * 'operation' is the operation type
3160  * 'canSetTag' is true if we set the command tag/es_processed
3161  * 'nominalRelation' is the parent RT index for use of EXPLAIN
3162  * 'partitioned_rels' is an integer list of RT indexes of non-leaf tables in
3163  * the partition tree, if this is an UPDATE/DELETE to a partitioned table.
3164  * Otherwise NIL.
3165  * 'resultRelations' is an integer list of actual RT indexes of target rel(s)
3166  * 'subpaths' is a list of Path(s) producing source data (one per rel)
3167  * 'subroots' is a list of PlannerInfo structs (one per rel)
3168  * 'withCheckOptionLists' is a list of WCO lists (one per rel)
3169  * 'returningLists' is a list of RETURNING tlists (one per rel)
3170  * 'rowMarks' is a list of PlanRowMarks (non-locking only)
3171  * 'onconflict' is the ON CONFLICT clause, or NULL
3172  * 'epqParam' is the ID of Param for EvalPlanQual re-eval
3173  */
3176  CmdType operation, bool canSetTag,
3177  Index nominalRelation, List *partitioned_rels,
3178  List *resultRelations, List *subpaths,
3179  List *subroots,
3180  List *withCheckOptionLists, List *returningLists,
3181  List *rowMarks, OnConflictExpr *onconflict,
3182  int epqParam)
3183 {
3185  double total_size;
3186  ListCell *lc;
3187 
3188  Assert(list_length(resultRelations) == list_length(subpaths));
3189  Assert(list_length(resultRelations) == list_length(subroots));
3190  Assert(withCheckOptionLists == NIL ||
3191  list_length(resultRelations) == list_length(withCheckOptionLists));
3192  Assert(returningLists == NIL ||
3193  list_length(resultRelations) == list_length(returningLists));
3194 
3195  pathnode->path.pathtype = T_ModifyTable;
3196  pathnode->path.parent = rel;
3197  /* pathtarget is not interesting, just make it minimally valid */
3198  pathnode->path.pathtarget = rel->reltarget;
3199  /* For now, assume we are above any joins, so no parameterization */
3200  pathnode->path.param_info = NULL;
3201  pathnode->path.parallel_aware = false;
3202  pathnode->path.parallel_safe = false;
3203  pathnode->path.parallel_workers = 0;
3204  pathnode->path.pathkeys = NIL;
3205 
3206  /*
3207  * Compute cost & rowcount as sum of subpath costs & rowcounts.
3208  *
3209  * Currently, we don't charge anything extra for the actual table
3210  * modification work, nor for the WITH CHECK OPTIONS or RETURNING
3211  * expressions if any. It would only be window dressing, since
3212  * ModifyTable is always a top-level node and there is no way for the
3213  * costs to change any higher-level planning choices. But we might want
3214  * to make it look better sometime.
3215  */
3216  pathnode->path.startup_cost = 0;
3217  pathnode->path.total_cost = 0;
3218  pathnode->path.rows = 0;
3219  total_size = 0;
3220  foreach(lc, subpaths)
3221  {
3222  Path *subpath = (Path *) lfirst(lc);
3223 
3224  if (lc == list_head(subpaths)) /* first node? */
3225  pathnode->path.startup_cost = subpath->startup_cost;
3226  pathnode->path.total_cost += subpath->total_cost;
3227  pathnode->path.rows += subpath->rows;
3228  total_size += subpath->pathtarget->width * subpath->rows;
3229  }
3230 
3231  /*
3232  * Set width to the average width of the subpath outputs. XXX this is
3233  * totally wrong: we should report zero if no RETURNING, else an average
3234  * of the RETURNING tlist widths. But it's what happened historically,
3235  * and improving it is a task for another day.
3236  */
3237  if (pathnode->path.rows > 0)
3238  total_size /= pathnode->path.rows;
3239  pathnode->path.pathtarget->width = rint(total_size);
3240 
3241  pathnode->operation = operation;
3242  pathnode->canSetTag = canSetTag;
3243  pathnode->nominalRelation = nominalRelation;
3244  pathnode->partitioned_rels = list_copy(partitioned_rels);
3245  pathnode->resultRelations = resultRelations;
3246  pathnode->subpaths = subpaths;
3247  pathnode->subroots = subroots;
3248  pathnode->withCheckOptionLists = withCheckOptionLists;
3249  pathnode->returningLists = returningLists;
3250  pathnode->rowMarks = rowMarks;
3251  pathnode->onconflict = onconflict;
3252  pathnode->epqParam = epqParam;
3253 
3254  return pathnode;
3255 }
3256 
3257 /*
3258  * create_limit_path
3259  * Creates a pathnode that represents performing LIMIT/OFFSET
3260  *
3261  * In addition to providing the actual OFFSET and LIMIT expressions,
3262  * the caller must provide estimates of their values for costing purposes.
3263  * The estimates are as computed by preprocess_limit(), ie, 0 represents
3264  * the clause not being present, and -1 means it's present but we could
3265  * not estimate its value.
3266  *
3267  * 'rel' is the parent relation associated with the result
3268  * 'subpath' is the path representing the source of data
3269  * 'limitOffset' is the actual OFFSET expression, or NULL
3270  * 'limitCount' is the actual LIMIT expression, or NULL
3271  * 'offset_est' is the estimated value of the OFFSET expression
3272  * 'count_est' is the estimated value of the LIMIT expression
3273  */
3274 LimitPath *
3276  Path *subpath,
3277  Node *limitOffset, Node *limitCount,
3278  int64 offset_est, int64 count_est)
3279 {
3280  LimitPath *pathnode = makeNode(LimitPath);
3281 
3282  pathnode->path.pathtype = T_Limit;
3283  pathnode->path.parent = rel;
3284  /* Limit doesn't project, so use source path's pathtarget */
3285  pathnode->path.pathtarget = subpath->pathtarget;
3286  /* For now, assume we are above any joins, so no parameterization */
3287  pathnode->path.param_info = NULL;
3288  pathnode->path.parallel_aware = false;
3289  pathnode->path.parallel_safe = rel->consider_parallel &&
3290  subpath->parallel_safe;
3291  pathnode->path.parallel_workers = subpath->parallel_workers;
3292  pathnode->path.rows = subpath->rows;
3293  pathnode->path.startup_cost = subpath->startup_cost;
3294  pathnode->path.total_cost = subpath->total_cost;
3295  pathnode->path.pathkeys = subpath->pathkeys;
3296  pathnode->subpath = subpath;
3297  pathnode->limitOffset = limitOffset;
3298  pathnode->limitCount = limitCount;
3299 
3300  /*
3301  * Adjust the output rows count and costs according to the offset/limit.
3302  * This is only a cosmetic issue if we are at top level, but if we are
3303  * building a subquery then it's important to report correct info to the
3304  * outer planner.
3305  *
3306  * When the offset or count couldn't be estimated, use 10% of the
3307  * estimated number of rows emitted from the subpath.
3308  *
3309  * XXX we don't bother to add eval costs of the offset/limit expressions
3310  * themselves to the path costs. In theory we should, but in most cases
3311  * those expressions are trivial and it's just not worth the trouble.
3312  */
3313  if (offset_est != 0)
3314  {
3315  double offset_rows;
3316 
3317  if (offset_est > 0)
3318  offset_rows = (double) offset_est;
3319  else
3320  offset_rows = clamp_row_est(subpath->rows * 0.10);
3321  if (offset_rows > pathnode->path.rows)
3322  offset_rows = pathnode->path.rows;
3323  if (subpath->rows > 0)
3324  pathnode->path.startup_cost +=
3325  (subpath->total_cost - subpath->startup_cost)
3326  * offset_rows / subpath->rows;
3327  pathnode->path.rows -= offset_rows;
3328  if (pathnode->path.rows < 1)
3329  pathnode->path.rows = 1;
3330  }
3331 
3332  if (count_est != 0)
3333  {
3334  double count_rows;
3335 
3336  if (count_est > 0)
3337  count_rows = (double) count_est;
3338  else
3339  count_rows = clamp_row_est(subpath->rows * 0.10);
3340  if (count_rows > pathnode->path.rows)
3341  count_rows = pathnode->path.rows;
3342  if (subpath->rows > 0)
3343  pathnode->path.total_cost = pathnode->path.startup_cost +
3344  (subpath->total_cost - subpath->startup_cost)
3345  * count_rows / subpath->rows;
3346  pathnode->path.rows = count_rows;
3347  if (pathnode->path.rows < 1)
3348  pathnode->path.rows = 1;
3349  }
3350 
3351  return pathnode;
3352 }
3353 
3354 
3355 /*
3356  * reparameterize_path
3357  * Attempt to modify a Path to have greater parameterization
3358  *
3359  * We use this to attempt to bring all child paths of an appendrel to the
3360  * same parameterization level, ensuring that they all enforce the same set
3361  * of join quals (and thus that that parameterization can be attributed to
3362  * an append path built from such paths). Currently, only a few path types
3363  * are supported here, though more could be added at need. We return NULL
3364  * if we can't reparameterize the given path.
3365  *
3366  * Note: we intentionally do not pass created paths to add_path(); it would
3367  * possibly try to delete them on the grounds of being cost-inferior to the
3368  * paths they were made from, and we don't want that. Paths made here are
3369  * not necessarily of general-purpose usefulness, but they can be useful
3370  * as members of an append path.
3371  */
3372 Path *
3374  Relids required_outer,
3375  double loop_count)
3376 {
3377  RelOptInfo *rel = path->parent;
3378 
3379  /* Can only increase, not decrease, path's parameterization */
3380  if (!bms_is_subset(PATH_REQ_OUTER(path), required_outer))
3381  return NULL;
3382  switch (path->pathtype)
3383  {
3384  case T_SeqScan:
3385  return create_seqscan_path(root, rel, required_outer, 0);
3386  case T_SampleScan:
3387  return (Path *) create_samplescan_path(root, rel, required_outer);
3388  case T_IndexScan:
3389  case T_IndexOnlyScan:
3390  {
3391  IndexPath *ipath = (IndexPath *) path;
3392  IndexPath *newpath = makeNode(IndexPath);
3393 
3394  /*
3395  * We can't use create_index_path directly, and would not want
3396  * to because it would re-compute the indexqual conditions
3397  * which is wasted effort. Instead we hack things a bit:
3398  * flat-copy the path node, revise its param_info, and redo
3399  * the cost estimate.
3400  */
3401  memcpy(newpath, ipath, sizeof(IndexPath));
3402  newpath->path.param_info =
3403  get_baserel_parampathinfo(root, rel, required_outer);
3404  cost_index(newpath, root, loop_count, false);
3405  return (Path *) newpath;
3406  }
3407  case T_BitmapHeapScan:
3408  {
3409  BitmapHeapPath *bpath = (BitmapHeapPath *) path;
3410 
3411  return (Path *) create_bitmap_heap_path(root,
3412  rel,
3413  bpath->bitmapqual,
3414  required_outer,
3415  loop_count, 0);
3416  }
3417  case T_SubqueryScan:
3418  {
3419  SubqueryScanPath *spath = (SubqueryScanPath *) path;
3420 
3421  return (Path *) create_subqueryscan_path(root,
3422  rel,
3423  spath->subpath,
3424  spath->path.pathkeys,
3425  required_outer);
3426  }
3427  default:
3428  break;
3429  }
3430  return NULL;
3431 }
Path * apply_projection_to_path(PlannerInfo *root, RelOptInfo *rel, Path *path, PathTarget *target)
Definition: pathnode.c:2370
void cost_group(Path *path, PlannerInfo *root, int numGroupCols, double numGroups, Cost input_startup_cost, Cost input_total_cost, double input_tuples)
Definition: costsize.c:2040
struct Path * cheapest_unique_path
Definition: relation.h:590
List * indexorderbycols
Definition: relation.h:1090
List * group_pathkeys
Definition: relation.h:264
#define NIL
Definition: pg_list.h:69
void final_cost_hashjoin(PlannerInfo *root, HashPath *path, JoinCostWorkspace *workspace, JoinPathExtraData *extra)
Definition: costsize.c:3012
List * qual
Definition: relation.h:1488
bool semi_can_btree
Definition: relation.h:1981
double estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows, List **pgset)
Definition: selfuncs.c:3351
List * path_mergeclauses
Definition: relation.h:1406
List * outersortkeys
Definition: relation.h:1407
List * distinctList
Definition: relation.h:1591
MinMaxAggPath * create_minmaxagg_path(PlannerInfo *root, RelOptInfo *rel, PathTarget *target, List *mmaggregates, List *quals)
Definition: pathnode.c:2886
Definition: nodes.h:77
GatherPath * create_gather_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, PathTarget *target, Relids required_outer, double *rows)
Definition: pathnode.c:1730
#define IsA(nodeptr, _type_)
Definition: nodes.h:560
JoinPath jpath
Definition: relation.h:1424
PathTarget * pathtarget
Definition: relation.h:1009
List * returningLists
Definition: relation.h:1640
bool query_is_distinct_for(Query *query, List *colnos, List *opids)
Definition: analyzejoins.c:782
OnConflictExpr * onconflict
Definition: relation.h:1642
void cost_bitmap_heap_scan(Path *path, PlannerInfo *root, RelOptInfo *baserel, ParamPathInfo *param_info, Path *bitmapqual, double loop_count)
Definition: costsize.c:928
Node * limitOffset
Definition: relation.h:1653
Path * subpath
Definition: relation.h:1500
void add_path(RelOptInfo *parent_rel, Path *new_path)
Definition: pathnode.c:412
Path path
Definition: relation.h:1084
SubqueryScanPath * create_subqueryscan_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, List *pathkeys, Relids required_outer)
Definition: pathnode.c:1769
Bitmapset * bms_copy(const Bitmapset *a)
Definition: bitmapset.c:111
Path * subpath
Definition: relation.h:1472
IndexOptInfo * indexinfo
Definition: relation.h:1085
ParamPathInfo * get_baserel_parampathinfo(PlannerInfo *root, RelOptInfo *baserel, Relids required_outer)
Definition: relnode.c:1068
Index nominalRelation
Definition: relation.h:1633
Path * fdw_outerpath
Definition: relation.h:1185
void cost_tidscan(Path *path, PlannerInfo *root, RelOptInfo *baserel, List *tidquals, ParamPathInfo *param_info)
Definition: costsize.c:1164
void cost_windowagg(Path *path, PlannerInfo *root, List *windowFuncs, int numPartCols, int numOrderCols, Cost input_startup_cost, Cost input_total_cost, double input_tuples)
Definition: costsize.c:1970
Definition: nodes.h:79
SetOpStrategy strategy
Definition: relation.h:1590
AggStrategy aggstrategy
Definition: relation.h:1515
LockRowsPath * create_lockrows_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, List *rowMarks, int epqParam)
Definition: pathnode.c:3116
void cost_gather_merge(GatherMergePath *path, PlannerInfo *root, RelOptInfo *rel, ParamPathInfo *param_info, Cost input_startup_cost, Cost input_total_cost, double *rows)
Definition: costsize.c:387
SetOpPath * create_setop_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, SetOpCmd cmd, SetOpStrategy strategy, List *distinctList, AttrNumber flagColIdx, int firstFlag, double numGroups, double outputRows)
Definition: pathnode.c:3009
ParamPathInfo * get_joinrel_parampathinfo(PlannerInfo *root, RelOptInfo *joinrel, Path *outer_path, Path *inner_path, SpecialJoinInfo *sjinfo, Relids required_outer, List **restrict_clauses)
Definition: relnode.c:1155
bool equal(const void *a, const void *b)
Definition: equalfuncs.c:2964
List * qual
Definition: relation.h:1519
double expression_returns_set_rows(Node *clause)
Definition: clauses.c:802
UpperUniquePath * create_upper_unique_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, int numCols, double numGroups)
Definition: pathnode.c:2615
bool add_partial_path_precheck(RelOptInfo *parent_rel, Cost total_cost, List *pathkeys)
Definition: pathnode.c:876
bool add_path_precheck(RelOptInfo *parent_rel, Cost startup_cost, Cost total_cost, List *pathkeys, Relids required_outer)
Definition: pathnode.c:647
Path * innerjoinpath
Definition: relation.h:1351
void cost_namedtuplestorescan(Path *path, PlannerInfo *root, RelOptInfo *baserel, ParamPathInfo *param_info)
Definition: costsize.c:1524
struct Path * cheapest_startup_path
Definition: relation.h:588
double tuples
Definition: relation.h:611
Path * subpath
Definition: relation.h:1588
List * rowMarks
Definition: relation.h:1641
BitmapOrPath * create_bitmap_or_path(PlannerInfo *root, RelOptInfo *rel, List *bitmapquals)
Definition: pathnode.c:1136
int parallel_workers
Definition: relation.h:1015
bool consider_param_startup
Definition: relation.h:578
void cost_bitmap_and_node(BitmapAndPath *path, PlannerInfo *root)
Definition: costsize.c:1072
MaterialPath * create_material_path(RelOptInfo *rel, Path *subpath)
Definition: pathnode.c:1388
static MemoryContext MemoryContextSwitchTo(MemoryContext context)
Definition: palloc.h:109
bool is_hashed
Definition: relation.h:1541
ParamPathInfo * param_info
Definition: relation.h:1011
Relids calc_non_nestloop_required_outer(Path *outer_path, Path *inner_path)
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List * list_copy(const List *oldlist)
Definition: list.c:1160
Definition: nodes.h:509
ProjectionPath * create_projection_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, PathTarget *target)
Definition: pathnode.c:2279
Definition: nodes.h:48
List * partial_pathlist
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AttrNumber varattno
Definition: primnodes.h:168
void cost_valuesscan(Path *path, PlannerInfo *root, RelOptInfo *baserel, ParamPathInfo *param_info)
Definition: costsize.c:1433
IndexPath * create_index_path(PlannerInfo *root, IndexOptInfo *index, List *indexclauses, List *indexclausecols, List *indexorderbys, List *indexorderbycols, List *pathkeys, ScanDirection indexscandir, bool indexonly, Relids required_outer, double loop_count, bool partial_path)
Definition: pathnode.c:1008
void cost_ctescan(Path *path, PlannerInfo *root, RelOptInfo *baserel, ParamPathInfo *param_info)
Definition: costsize.c:1483
return result
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List * cheapest_parameterized_paths
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bool single_copy
Definition: relation.h:1320
UniquePathMethod umethod
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PathKeysComparison compare_pathkeys(List *keys1, List *keys2)
Definition: pathkeys.c:278
Definition: nodes.h:75
UniquePath * create_unique_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, SpecialJoinInfo *sjinfo)
Definition: pathnode.c:1427
Path * subpath
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List * indexclauses
Definition: relation.h:1086
AggSplit aggsplit
Definition: relation.h:1516
List * partitioned_rels
Definition: relation.h:1253
MergePath * create_mergejoin_path(PlannerInfo *root, RelOptInfo *joinrel, JoinType jointype, JoinCostWorkspace *workspace, JoinPathExtraData *extra, Path *outer_path, Path *inner_path, List *restrict_clauses, List *pathkeys, Relids required_outer, List *mergeclauses, List *outersortkeys, List *innersortkeys)
Definition: pathnode.c:2150
List * quals
Definition: relation.h:1564
Definition: primnodes.h:163
AppendPath * create_append_path(RelOptInfo *rel, List *subpaths, Relids required_outer, int parallel_workers, List *partitioned_rels)
Definition: pathnode.c:1203
LimitPath * create_limit_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, Node *limitOffset, Node *limitCount, int64 offset_est, int64 count_est)
Definition: pathnode.c:3275
Path * create_functionscan_path(PlannerInfo *root, RelOptInfo *rel, List *pathkeys, Relids required_outer)
Definition: pathnode.c:1797
double numGroups
Definition: relation.h:1517
double numGroups
Definition: relation.h:1594
SetOpStrategy
Definition: nodes.h:787
List * rowMarks
Definition: relation.h:1617
List * winpathkeys
Definition: relation.h:1579
double numGroups
Definition: relation.h:1539
Cost startup
Definition: relation.h:45
List * bitmapquals
Definition: relation.h:1128
Path path
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JoinType
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WindowClause * winclause
Definition: relation.h:1578
Path * create_valuesscan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
Definition: pathnode.c:1849
List * bitmapquals
Definition: relation.h:1141
int num_workers
Definition: relation.h:1321
Definition: type.h:89
NodeTag pathtype
Definition: relation.h:1006
Relids syn_righthand
Definition: relation.h:1976
List * subpaths
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SetOpCmd cmd
Definition: relation.h:1589
void final_cost_nestloop(PlannerInfo *root, NestPath *path, JoinCostWorkspace *workspace, JoinPathExtraData *extra)
Definition: costsize.c:2162
ListCell * lappend_cell(List *list, ListCell *prev, void *datum)
Definition: list.c:209
bool consider_startup
Definition: relation.h:577
bool is_parallel_safe(PlannerInfo *root, Node *node)
Definition: clauses.c:1087
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Definition: costsize.c:197
Cost per_tuple
Definition: relation.h:46
GroupingSetsPath * create_groupingsets_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, PathTarget *target, List *having_qual, AggStrategy aggstrategy, List *rollups, const AggClauseCosts *agg_costs, double numGroups)
Definition: pathnode.c:2732
List * indexquals
Definition: relation.h:1087
Path * subpath
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void pfree(void *pointer)
Definition: mcxt.c:949
RelOptInfo * rel
Definition: relation.h:687
SpecialJoinInfo * sjinfo
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Path path
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#define linitial(l)
Definition: pg_list.h:111
#define planner_rt_fetch(rti, root)
Definition: relation.h:328
Definition: nodes.h:45
Relids all_baserels
Definition: relation.h:196
#define ERROR
Definition: elog.h:43
static List * translate_sub_tlist(List *tlist, int relid)
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double limit_tuples
Definition: relation.h:295
List * partitionClause
Definition: parsenodes.h:1283
void cost_qual_eval(QualCost *cost, List *quals, PlannerInfo *root)
Definition: costsize.c:3463
void expand_indexqual_conditions(IndexOptInfo *index, List *indexclauses, List *indexclausecols, List **indexquals_p, List **indexqualcols_p)
Definition: indxpath.c:3526
Cost startup_cost
Definition: relation.h:1019
RecursiveUnionPath * create_recursiveunion_path(PlannerInfo *root, RelOptInfo *rel, Path *leftpath, Path *rightpath, PathTarget *target, List *distinctList, int wtParam, double numGroups)
Definition: pathnode.c:3071
List * semi_rhs_exprs
Definition: relation.h:1984
void cost_subqueryscan(SubqueryScanPath *path, PlannerInfo *root, RelOptInfo *baserel, ParamPathInfo *param_info)
Definition: costsize.c:1267
bool semi_can_hash
Definition: relation.h:1982
Path * subpath
Definition: relation.h:1652
List * joinrestrictinfo
Definition: relation.h:1353
List * subroots
Definition: relation.h:1638
RelOptInfo * parent
Definition: relation.h:1008
List * uniq_exprs
Definition: relation.h:1308
Path * bitmapqual
Definition: relation.h:1116
bool bms_is_subset(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:308
Definition: nodes.h:76
Path path
Definition: relation.h:1485
int compare_path_costs(Path *path1, Path *path2, CostSelector criterion)
Definition: pathnode.c:61
NestPath * create_nestloop_path(PlannerInfo *root, RelOptInfo *joinrel, JoinType jointype, JoinCostWorkspace *workspace, JoinPathExtraData *extra, Path *outer_path, Path *inner_path, List *restrict_clauses, List *pathkeys, Relids required_outer)
Definition: pathnode.c:2062
AggPath * create_agg_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, PathTarget *target, AggStrategy aggstrategy, AggSplit aggsplit, List *groupClause, List *qual, const AggClauseCosts *aggcosts, double numGroups)
Definition: pathnode.c:2667
struct Path * cheapest_total_path
Definition: relation.h:589
ForeignPath * create_foreignscan_path(PlannerInfo *root, RelOptInfo *rel, PathTarget *target, double rows, Cost startup_cost, Cost total_cost, List *pathkeys, Relids required_outer, Path *fdw_outerpath, List *fdw_private)
Definition: pathnode.c:1960
ProjectSetPath * create_set_projection_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, PathTarget *target)
Definition: pathnode.c:2446
static PathCostComparison compare_path_costs_fuzzily(Path *path1, Path *path2, double fuzz_factor)
Definition: pathnode.c:156
ScanDirection
Definition: sdir.h:22
void cost_agg(Path *path, PlannerInfo *root, AggStrategy aggstrategy, const AggClauseCosts *aggcosts, int numGroupCols, double numGroups, Cost input_startup_cost, Cost input_total_cost, double input_tuples)
Definition: costsize.c:1873
GroupPath * create_group_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, PathTarget *target, List *groupClause, List *qual, double numGroups)
Definition: pathnode.c:2557
List * subpaths
Definition: relation.h:1637
List * groupClause
Definition: relation.h:1518
static ListCell * list_head(const List *l)
Definition: pg_list.h:77
AttrNumber flagColIdx
Definition: relation.h:1592
MergeAppendPath * create_merge_append_path(PlannerInfo *root, RelOptInfo *rel, List *subpaths, List *pathkeys, Relids required_outer, List *partitioned_rels)
Definition: pathnode.c:1257
Relids relids
Definition: relation.h:571
AggStrategy aggstrategy
Definition: relation.h:1552
double cpu_operator_cost
Definition: costsize.c:108
Path * subpath
Definition: relation.h:1319
double rint(double x)
Definition: rint.c:22
void cost_samplescan(Path *path, PlannerInfo *root, RelOptInfo *baserel, ParamPathInfo *param_info)
Definition: costsize.c:274
#define lnext(lc)
Definition: pg_list.h:105
bool join_clause_is_movable_into(RestrictInfo *rinfo, Relids currentrelids, Relids current_and_outer)
Definition: restrictinfo.c:510
List * lappend_int(List *list, int datum)
Definition: list.c:146
Index relid
Definition: relation.h:599
Path * create_worktablescan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
Definition: pathnode.c:1926
List * lappend(List *list, void *datum)
Definition: list.c:128
Path * subpath
Definition: relation.h:1616
bool bms_is_empty(const Bitmapset *a)
Definition: bitmapset.c:663
Index varno
Definition: primnodes.h:166
void set_cheapest(RelOptInfo *parent_rel)
Definition: pathnode.c:234
List * exprs
Definition: relation.h:938
BitmapAndPath * create_bitmap_and_path(PlannerInfo *root, RelOptInfo *rel, List *bitmapquals)
Definition: pathnode.c:1100
List * list_delete_cell(List *list, ListCell *cell, ListCell *prev)
Definition: list.c:528
bool pathkeys_contained_in(List *keys1, List *keys2)
Definition: pathkeys.c:317
Path * outerjoinpath
Definition: relation.h:1350
void cost_index(IndexPath *path, PlannerInfo *root, double loop_count, bool partial_path)
Definition: costsize.c:462
List * indexorderbys
Definition: relation.h:1089
void cost_recursive_union(Path *runion, Path *nrterm, Path *rterm)
Definition: costsize.c:1564
WindowAggPath * create_windowagg_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, PathTarget *target, List *windowFuncs, WindowClause *winclause, List *winpathkeys)
Definition: pathnode.c:2945
Path * create_samplescan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
Definition: pathnode.c:963
List * groupClause
Definition: relation.h:1487
Path * create_tablefuncscan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
Definition: pathnode.c:1823
List * mmaggregates
Definition: relation.h:1563
List * partitioned_rels
Definition: relation.h:1635
List * tidquals
Definition: relation.h:1155
void cost_sort(Path *path, PlannerInfo *root, List *pathkeys, Cost input_cost, double tuples, int width, Cost comparison_cost, int sort_mem, double limit_tuples)
Definition: costsize.c:1644
int work_mem
Definition: globals.c:113
Path * subpath
Definition: relation.h:1486
unsigned int Index
Definition: c.h:359
RTEKind rtekind
Definition: relation.h:601
PathCostComparison
Definition: pathnode.c:33
List * in_operators
Definition: relation.h:1307
double rows
Definition: relation.h:574
GatherMergePath * create_gather_merge_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, PathTarget *target, List *pathkeys, Relids required_outer, double *rows)
Definition: pathnode.c:1639
SortPath * create_sort_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath, List *pathkeys, double limit_tuples)
Definition: pathnode.c:2513
BMS_Comparison bms_subset_compare(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:345
Cost total_cost
Definition: relation.h:1020
void cost_material(Path *path, Cost input_startup_cost, Cost input_total_cost, double tuples, int width)
Definition: costsize.c:1819
int firstFlag
Definition: relation.h:1593
List * lcons(void *datum, List *list)
Definition: list.c:259
List * pathkeys
Definition: relation.h:1022
void bms_free(Bitmapset *a)
Definition: bitmapset.c:201
#define makeNode(_type_)
Definition: nodes.h:557
void cost_tablefuncscan(Path *path, PlannerInfo *root, RelOptInfo *baserel, ParamPathInfo *param_info)
Definition: costsize.c:1377
void cost_merge_append(Path *path, PlannerInfo *root, List *pathkeys, int n_streams, Cost input_startup_cost, Cost input_total_cost, double tuples)
Definition: costsize.c:1768
#define CONSIDER_PATH_STARTUP_COST(p)
Path path
Definition: relation.h:1343
#define Assert(condition)
Definition: c.h:664
#define lfirst(lc)
Definition: pg_list.h:106
Path * subpath
Definition: relation.h:1458
double rows
Definition: relation.h:1018
bool parallel_safe
Definition: relation.h:1014
ModifyTablePath * create_modifytable_path(PlannerInfo *root, RelOptInfo *rel, CmdType operation, bool canSetTag, Index nominalRelation, List *partitioned_rels, List *resultRelations, List *subpaths, List *subroots, List *withCheckOptionLists, List *returningLists, List *rowMarks, OnConflictExpr *onconflict, int epqParam)
Definition: pathnode.c:3175
int compare_fractional_path_costs(Path *path1, Path *path2, double fraction)
Definition: pathnode.c:107
List * quals
Definition: relation.h:1268
#define PATH_REQ_OUTER(path)
Definition: relation.h:1027
JoinType jointype
Definition: relation.h:1977
Bitmapset * bms_union(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:218
#define STD_FUZZ_FACTOR
Definition: pathnode.c:46
QualCost cost
Definition: relation.h:940
AggSplit
Definition: nodes.h:757
static int list_length(const List *l)
Definition: pg_list.h:89
Relids calc_nestloop_required_outer(Relids outerrelids, Relids outer_paramrels, Relids innerrelids, Relids inner_paramrels)
Definition: pathnode.c:1996
CostSelector
Definition: relation.h:34
bool inner_unique
Definition: relation.h:1347
bool consider_parallel
Definition: relation.h:579
List * innersortkeys
Definition: relation.h:1408
double cpu_tuple_cost
Definition: costsize.c:106
Path * subpath
Definition: relation.h:1514
bool query_supports_distinctness(Query *query)
Definition: analyzejoins.c:745
List * partitioned_rels
Definition: relation.h:1233
void cost_gather(GatherPath *path, PlannerInfo *root, RelOptInfo *rel, ParamPathInfo *param_info, double *rows)
Definition: costsize.c:349
Path * subpath
Definition: relation.h:1332
Path path
Definition: relation.h:1651
Path path
Definition: relation.h:1154
List * withCheckOptionLists
Definition: relation.h:1639
Bitmapset * bms_del_members(Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:817
bool bms_overlap(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:443
List * indexqualcols
Definition: relation.h:1088
Definition: nodes.h:83
List * orderClause
Definition: parsenodes.h:1284
PathKeysComparison
Definition: paths.h:175
int width
Definition: relation.h:941
Query * subquery
Definition: parsenodes.h:968
AggStrategy
Definition: nodes.h:735
bool is_projection_capable_path(Path *path)
Definition: createplan.c:6546
TidPath * create_tidscan_path(PlannerInfo *root, RelOptInfo *rel, List *tidquals, Relids required_outer)
Definition: pathnode.c:1172
Path * reparameterize_path(PlannerInfo *root, Path *path, Relids required_outer, double loop_count)
Definition: pathnode.c:3373
HashPath * create_hashjoin_path(PlannerInfo *root, RelOptInfo *joinrel, JoinType jointype, JoinCostWorkspace *workspace, JoinPathExtraData *extra, Path *outer_path, Path *inner_path, List *restrict_clauses, Relids required_outer, List *hashclauses)
Definition: pathnode.c:2215
void cost_functionscan(Path *path, PlannerInfo *root, RelOptInfo *baserel, ParamPathInfo *param_info)
Definition: costsize.c:1316
void add_partial_path(RelOptInfo *parent_rel, Path *new_path)
Definition: pathnode.c:752
List * fdw_private
Definition: relation.h:1186
SetOpCmd
Definition: nodes.h:779
JoinType jointype
Definition: relation.h:1345
List * semi_operators
Definition: relation.h:1983
ScanDirection indexscandir
Definition: relation.h:1091
CmdType operation
Definition: relation.h:1631
Definition: nodes.h:80
List * resultRelations
Definition: relation.h:1636
void cost_bitmap_or_node(BitmapOrPath *path, PlannerInfo *root)
Definition: costsize.c:1116
JoinPath jpath
Definition: relation.h:1405
ResultPath * create_result_path(PlannerInfo *root, RelOptInfo *rel, PathTarget *target, List *resconstantqual)
Definition: pathnode.c:1349
bool parallel_aware
Definition: relation.h:1013
List * path_hashclauses
Definition: relation.h:1425
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:98
List * pathlist
Definition: relation.h:585
List * subpaths
Definition: relation.h:1254
MemoryContext planner_cxt
Definition: relation.h:290
#define elog
Definition: elog.h:219
ParamPathInfo * get_appendrel_parampathinfo(RelOptInfo *appendrel, Relids required_outer)
Definition: relnode.c:1359
bool relation_has_unique_index_for(PlannerInfo *root, RelOptInfo *rel, List *restrictlist, List *exprlist, List *oprlist)
Definition: indxpath.c:2960
Path * subpath
Definition: relation.h:1446
Path path
Definition: relation.h:1318
double clamp_row_est(double nrows)
Definition: costsize.c:173
Node * limitCount
Definition: relation.h:1654
Definition: pg_list.h:45
Path path
Definition: relation.h:1471
struct PathTarget * reltarget
Definition: relation.h:582
int16 AttrNumber
Definition: attnum.h:21
Path path
Definition: relation.h:1587
Path path
Definition: relation.h:1304
CmdType
Definition: nodes.h:649
Path * create_seqscan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer, int parallel_workers)
Definition: pathnode.c:938
Path path
Definition: relation.h:1513
double limit_tuples
Definition: relation.h:1255
BMS_Comparison
Definition: bitmapset.h:45
double Cost
Definition: nodes.h:640
Datum subpath(PG_FUNCTION_ARGS)
Definition: ltree_op.c:234
bool bms_equal(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:131
void final_cost_mergejoin(PlannerInfo *root, MergePath *path, JoinCostWorkspace *workspace, JoinPathExtraData *extra)
Definition: costsize.c:2599
List * gsets
Definition: relation.h:1537
static int cmp(const chr *x, const chr *y, size_t len)
Definition: regc_locale.c:742
Path * subpath
Definition: relation.h:1305
BitmapHeapPath * create_bitmap_heap_path(PlannerInfo *root, RelOptInfo *rel, Path *bitmapqual, Relids required_outer, double loop_count, int parallel_degree)
Definition: pathnode.c:1067
Path * create_namedtuplestorescan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
Definition: pathnode.c:1900
Definition: nodes.h:85
Path * create_ctescan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
Definition: pathnode.c:1875