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subselect.c
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1 /*-------------------------------------------------------------------------
2  *
3  * subselect.c
4  * Planning routines for subselects.
5  *
6  * This module deals with SubLinks and CTEs, but not subquery RTEs (i.e.,
7  * not sub-SELECT-in-FROM cases).
8  *
9  * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
10  * Portions Copyright (c) 1994, Regents of the University of California
11  *
12  * IDENTIFICATION
13  * src/backend/optimizer/plan/subselect.c
14  *
15  *-------------------------------------------------------------------------
16  */
17 #include "postgres.h"
18 
19 #include "access/htup_details.h"
20 #include "catalog/pg_operator.h"
21 #include "catalog/pg_type.h"
22 #include "executor/executor.h"
23 #include "miscadmin.h"
24 #include "nodes/makefuncs.h"
25 #include "nodes/nodeFuncs.h"
26 #include "optimizer/clauses.h"
27 #include "optimizer/cost.h"
28 #include "optimizer/optimizer.h"
29 #include "optimizer/paramassign.h"
30 #include "optimizer/pathnode.h"
31 #include "optimizer/planmain.h"
32 #include "optimizer/planner.h"
33 #include "optimizer/prep.h"
34 #include "optimizer/subselect.h"
35 #include "parser/parse_relation.h"
36 #include "rewrite/rewriteManip.h"
37 #include "utils/builtins.h"
38 #include "utils/lsyscache.h"
39 #include "utils/syscache.h"
40 
41 
43 {
45  List *subst_nodes; /* Nodes to substitute for Params */
47 
49 {
51  bool isTopQual;
53 
55 {
57  Bitmapset *paramids; /* Non-local PARAM_EXEC paramids found */
59 
61 {
62  const char *ctename; /* name and relative level of target CTE */
63  int levelsup;
64  int refcount; /* number of remaining references */
65  Query *ctequery; /* query to substitute */
67 
68 
69 static Node *build_subplan(PlannerInfo *root, Plan *plan, PlannerInfo *subroot,
70  List *plan_params,
71  SubLinkType subLinkType, int subLinkId,
72  Node *testexpr, bool adjust_testexpr,
73  bool unknownEqFalse);
75  List **paramIds);
77  Index varno);
79  Node *testexpr,
80  List *subst_nodes);
81 static Node *convert_testexpr_mutator(Node *node,
82  convert_testexpr_context *context);
83 static bool subplan_is_hashable(Plan *plan);
84 static bool testexpr_is_hashable(Node *testexpr);
85 static bool hash_ok_operator(OpExpr *expr);
86 static bool contain_dml(Node *node);
87 static bool contain_dml_walker(Node *node, void *context);
88 static bool contain_outer_selfref(Node *node);
89 static bool contain_outer_selfref_walker(Node *node, Index *depth);
90 static void inline_cte(PlannerInfo *root, CommonTableExpr *cte);
91 static bool inline_cte_walker(Node *node, inline_cte_walker_context *context);
92 static bool simplify_EXISTS_query(PlannerInfo *root, Query *query);
93 static Query *convert_EXISTS_to_ANY(PlannerInfo *root, Query *subselect,
94  Node **testexpr, List **paramIds);
96 static Node *process_sublinks_mutator(Node *node,
97  process_sublinks_context *context);
99  Plan *plan,
100  int gather_param,
101  Bitmapset *valid_params,
102  Bitmapset *scan_params);
103 static bool finalize_primnode(Node *node, finalize_primnode_context *context);
104 static bool finalize_agg_primnode(Node *node, finalize_primnode_context *context);
105 
106 
107 /*
108  * Get the datatype/typmod/collation of the first column of the plan's output.
109  *
110  * This information is stored for ARRAY_SUBLINK execution and for
111  * exprType()/exprTypmod()/exprCollation(), which have no way to get at the
112  * plan associated with a SubPlan node. We really only need the info for
113  * EXPR_SUBLINK and ARRAY_SUBLINK subplans, but for consistency we save it
114  * always.
115  */
116 static void
117 get_first_col_type(Plan *plan, Oid *coltype, int32 *coltypmod,
118  Oid *colcollation)
119 {
120  /* In cases such as EXISTS, tlist might be empty; arbitrarily use VOID */
121  if (plan->targetlist)
122  {
124 
125  if (!tent->resjunk)
126  {
127  *coltype = exprType((Node *) tent->expr);
128  *coltypmod = exprTypmod((Node *) tent->expr);
129  *colcollation = exprCollation((Node *) tent->expr);
130  return;
131  }
132  }
133  *coltype = VOIDOID;
134  *coltypmod = -1;
135  *colcollation = InvalidOid;
136 }
137 
138 /*
139  * Convert a SubLink (as created by the parser) into a SubPlan.
140  *
141  * We are given the SubLink's contained query, type, ID, and testexpr. We are
142  * also told if this expression appears at top level of a WHERE/HAVING qual.
143  *
144  * Note: we assume that the testexpr has been AND/OR flattened (actually,
145  * it's been through eval_const_expressions), but not converted to
146  * implicit-AND form; and any SubLinks in it should already have been
147  * converted to SubPlans. The subquery is as yet untouched, however.
148  *
149  * The result is whatever we need to substitute in place of the SubLink node
150  * in the executable expression. If we're going to do the subplan as a
151  * regular subplan, this will be the constructed SubPlan node. If we're going
152  * to do the subplan as an InitPlan, the SubPlan node instead goes into
153  * root->init_plans, and what we return here is an expression tree
154  * representing the InitPlan's result: usually just a Param node representing
155  * a single scalar result, but possibly a row comparison tree containing
156  * multiple Param nodes, or for a MULTIEXPR subquery a simple NULL constant
157  * (since the real output Params are elsewhere in the tree, and the MULTIEXPR
158  * subquery itself is in a resjunk tlist entry whose value is uninteresting).
159  */
160 static Node *
162  SubLinkType subLinkType, int subLinkId,
163  Node *testexpr, bool isTopQual)
164 {
165  Query *subquery;
166  bool simple_exists = false;
167  double tuple_fraction;
168  PlannerInfo *subroot;
169  RelOptInfo *final_rel;
170  Path *best_path;
171  Plan *plan;
172  List *plan_params;
173  Node *result;
174 
175  /*
176  * Copy the source Query node. This is a quick and dirty kluge to resolve
177  * the fact that the parser can generate trees with multiple links to the
178  * same sub-Query node, but the planner wants to scribble on the Query.
179  * Try to clean this up when we do querytree redesign...
180  */
181  subquery = copyObject(orig_subquery);
182 
183  /*
184  * If it's an EXISTS subplan, we might be able to simplify it.
185  */
186  if (subLinkType == EXISTS_SUBLINK)
187  simple_exists = simplify_EXISTS_query(root, subquery);
188 
189  /*
190  * For an EXISTS subplan, tell lower-level planner to expect that only the
191  * first tuple will be retrieved. For ALL and ANY subplans, we will be
192  * able to stop evaluating if the test condition fails or matches, so very
193  * often not all the tuples will be retrieved; for lack of a better idea,
194  * specify 50% retrieval. For EXPR, MULTIEXPR, and ROWCOMPARE subplans,
195  * use default behavior (we're only expecting one row out, anyway).
196  *
197  * NOTE: if you change these numbers, also change cost_subplan() in
198  * path/costsize.c.
199  *
200  * XXX If an ANY subplan is uncorrelated, build_subplan may decide to hash
201  * its output. In that case it would've been better to specify full
202  * retrieval. At present, however, we can only check hashability after
203  * we've made the subplan :-(. (Determining whether it'll fit in work_mem
204  * is the really hard part.) Therefore, we don't want to be too
205  * optimistic about the percentage of tuples retrieved, for fear of
206  * selecting a plan that's bad for the materialization case.
207  */
208  if (subLinkType == EXISTS_SUBLINK)
209  tuple_fraction = 1.0; /* just like a LIMIT 1 */
210  else if (subLinkType == ALL_SUBLINK ||
211  subLinkType == ANY_SUBLINK)
212  tuple_fraction = 0.5; /* 50% */
213  else
214  tuple_fraction = 0.0; /* default behavior */
215 
216  /* plan_params should not be in use in current query level */
217  Assert(root->plan_params == NIL);
218 
219  /* Generate Paths for the subquery */
220  subroot = subquery_planner(root->glob, subquery,
221  root,
222  false, tuple_fraction);
223 
224  /* Isolate the params needed by this specific subplan */
225  plan_params = root->plan_params;
226  root->plan_params = NIL;
227 
228  /*
229  * Select best Path and turn it into a Plan. At least for now, there
230  * seems no reason to postpone doing that.
231  */
232  final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
233  best_path = get_cheapest_fractional_path(final_rel, tuple_fraction);
234 
235  plan = create_plan(subroot, best_path);
236 
237  /* And convert to SubPlan or InitPlan format. */
238  result = build_subplan(root, plan, subroot, plan_params,
239  subLinkType, subLinkId,
240  testexpr, true, isTopQual);
241 
242  /*
243  * If it's a correlated EXISTS with an unimportant targetlist, we might be
244  * able to transform it to the equivalent of an IN and then implement it
245  * by hashing. We don't have enough information yet to tell which way is
246  * likely to be better (it depends on the expected number of executions of
247  * the EXISTS qual, and we are much too early in planning the outer query
248  * to be able to guess that). So we generate both plans, if possible, and
249  * leave it to the executor to decide which to use.
250  */
251  if (simple_exists && IsA(result, SubPlan))
252  {
253  Node *newtestexpr;
254  List *paramIds;
255 
256  /* Make a second copy of the original subquery */
257  subquery = copyObject(orig_subquery);
258  /* and re-simplify */
259  simple_exists = simplify_EXISTS_query(root, subquery);
260  Assert(simple_exists);
261  /* See if it can be converted to an ANY query */
262  subquery = convert_EXISTS_to_ANY(root, subquery,
263  &newtestexpr, &paramIds);
264  if (subquery)
265  {
266  /* Generate Paths for the ANY subquery; we'll need all rows */
267  subroot = subquery_planner(root->glob, subquery,
268  root,
269  false, 0.0);
270 
271  /* Isolate the params needed by this specific subplan */
272  plan_params = root->plan_params;
273  root->plan_params = NIL;
274 
275  /* Select best Path and turn it into a Plan */
276  final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
277  best_path = final_rel->cheapest_total_path;
278 
279  plan = create_plan(subroot, best_path);
280 
281  /* Now we can check if it'll fit in work_mem */
282  /* XXX can we check this at the Path stage? */
283  if (subplan_is_hashable(plan))
284  {
285  SubPlan *hashplan;
286  AlternativeSubPlan *asplan;
287 
288  /* OK, convert to SubPlan format. */
289  hashplan = castNode(SubPlan,
290  build_subplan(root, plan, subroot,
291  plan_params,
292  ANY_SUBLINK, 0,
293  newtestexpr,
294  false, true));
295  /* Check we got what we expected */
296  Assert(hashplan->parParam == NIL);
297  Assert(hashplan->useHashTable);
298  /* build_subplan won't have filled in paramIds */
299  hashplan->paramIds = paramIds;
300 
301  /* Leave it to the executor to decide which plan to use */
302  asplan = makeNode(AlternativeSubPlan);
303  asplan->subplans = list_make2(result, hashplan);
304  result = (Node *) asplan;
305  }
306  }
307  }
308 
309  return result;
310 }
311 
312 /*
313  * Build a SubPlan node given the raw inputs --- subroutine for make_subplan
314  *
315  * Returns either the SubPlan, or a replacement expression if we decide to
316  * make it an InitPlan, as explained in the comments for make_subplan.
317  */
318 static Node *
320  List *plan_params,
321  SubLinkType subLinkType, int subLinkId,
322  Node *testexpr, bool adjust_testexpr,
323  bool unknownEqFalse)
324 {
325  Node *result;
326  SubPlan *splan;
327  bool isInitPlan;
328  ListCell *lc;
329 
330  /*
331  * Initialize the SubPlan node. Note plan_id, plan_name, and cost fields
332  * are set further down.
333  */
334  splan = makeNode(SubPlan);
335  splan->subLinkType = subLinkType;
336  splan->testexpr = NULL;
337  splan->paramIds = NIL;
338  get_first_col_type(plan, &splan->firstColType, &splan->firstColTypmod,
339  &splan->firstColCollation);
340  splan->useHashTable = false;
341  splan->unknownEqFalse = unknownEqFalse;
342  splan->parallel_safe = plan->parallel_safe;
343  splan->setParam = NIL;
344  splan->parParam = NIL;
345  splan->args = NIL;
346 
347  /*
348  * Make parParam and args lists of param IDs and expressions that current
349  * query level will pass to this child plan.
350  */
351  foreach(lc, plan_params)
352  {
353  PlannerParamItem *pitem = (PlannerParamItem *) lfirst(lc);
354  Node *arg = pitem->item;
355 
356  /*
357  * The Var, PlaceHolderVar, or Aggref has already been adjusted to
358  * have the correct varlevelsup, phlevelsup, or agglevelsup.
359  *
360  * If it's a PlaceHolderVar or Aggref, its arguments might contain
361  * SubLinks, which have not yet been processed (see the comments for
362  * SS_replace_correlation_vars). Do that now.
363  */
364  if (IsA(arg, PlaceHolderVar) ||
365  IsA(arg, Aggref))
366  arg = SS_process_sublinks(root, arg, false);
367 
368  splan->parParam = lappend_int(splan->parParam, pitem->paramId);
369  splan->args = lappend(splan->args, arg);
370  }
371 
372  /*
373  * Un-correlated or undirect correlated plans of EXISTS, EXPR, ARRAY,
374  * ROWCOMPARE, or MULTIEXPR types can be used as initPlans. For EXISTS,
375  * EXPR, or ARRAY, we return a Param referring to the result of evaluating
376  * the initPlan. For ROWCOMPARE, we must modify the testexpr tree to
377  * contain PARAM_EXEC Params instead of the PARAM_SUBLINK Params emitted
378  * by the parser, and then return that tree. For MULTIEXPR, we return a
379  * null constant: the resjunk targetlist item containing the SubLink does
380  * not need to return anything useful, since the referencing Params are
381  * elsewhere.
382  */
383  if (splan->parParam == NIL && subLinkType == EXISTS_SUBLINK)
384  {
385  Param *prm;
386 
387  Assert(testexpr == NULL);
388  prm = generate_new_exec_param(root, BOOLOID, -1, InvalidOid);
389  splan->setParam = list_make1_int(prm->paramid);
390  isInitPlan = true;
391  result = (Node *) prm;
392  }
393  else if (splan->parParam == NIL && subLinkType == EXPR_SUBLINK)
394  {
395  TargetEntry *te = linitial(plan->targetlist);
396  Param *prm;
397 
398  Assert(!te->resjunk);
399  Assert(testexpr == NULL);
400  prm = generate_new_exec_param(root,
401  exprType((Node *) te->expr),
402  exprTypmod((Node *) te->expr),
403  exprCollation((Node *) te->expr));
404  splan->setParam = list_make1_int(prm->paramid);
405  isInitPlan = true;
406  result = (Node *) prm;
407  }
408  else if (splan->parParam == NIL && subLinkType == ARRAY_SUBLINK)
409  {
410  TargetEntry *te = linitial(plan->targetlist);
411  Oid arraytype;
412  Param *prm;
413 
414  Assert(!te->resjunk);
415  Assert(testexpr == NULL);
416  arraytype = get_promoted_array_type(exprType((Node *) te->expr));
417  if (!OidIsValid(arraytype))
418  elog(ERROR, "could not find array type for datatype %s",
419  format_type_be(exprType((Node *) te->expr)));
420  prm = generate_new_exec_param(root,
421  arraytype,
422  exprTypmod((Node *) te->expr),
423  exprCollation((Node *) te->expr));
424  splan->setParam = list_make1_int(prm->paramid);
425  isInitPlan = true;
426  result = (Node *) prm;
427  }
428  else if (splan->parParam == NIL && subLinkType == ROWCOMPARE_SUBLINK)
429  {
430  /* Adjust the Params */
431  List *params;
432 
433  Assert(testexpr != NULL);
434  params = generate_subquery_params(root,
435  plan->targetlist,
436  &splan->paramIds);
437  result = convert_testexpr(root,
438  testexpr,
439  params);
440  splan->setParam = list_copy(splan->paramIds);
441  isInitPlan = true;
442 
443  /*
444  * The executable expression is returned to become part of the outer
445  * plan's expression tree; it is not kept in the initplan node.
446  */
447  }
448  else if (subLinkType == MULTIEXPR_SUBLINK)
449  {
450  /*
451  * Whether it's an initplan or not, it needs to set a PARAM_EXEC Param
452  * for each output column.
453  */
454  List *params;
455 
456  Assert(testexpr == NULL);
457  params = generate_subquery_params(root,
458  plan->targetlist,
459  &splan->setParam);
460 
461  /*
462  * Save the list of replacement Params in the n'th cell of
463  * root->multiexpr_params; setrefs.c will use it to replace
464  * PARAM_MULTIEXPR Params.
465  */
466  while (list_length(root->multiexpr_params) < subLinkId)
468  lc = list_nth_cell(root->multiexpr_params, subLinkId - 1);
469  Assert(lfirst(lc) == NIL);
470  lfirst(lc) = params;
471 
472  /* It can be an initplan if there are no parParams. */
473  if (splan->parParam == NIL)
474  {
475  isInitPlan = true;
476  result = (Node *) makeNullConst(RECORDOID, -1, InvalidOid);
477  }
478  else
479  {
480  isInitPlan = false;
481  result = (Node *) splan;
482  }
483  }
484  else
485  {
486  /*
487  * Adjust the Params in the testexpr, unless caller said it's not
488  * needed.
489  */
490  if (testexpr && adjust_testexpr)
491  {
492  List *params;
493 
494  params = generate_subquery_params(root,
495  plan->targetlist,
496  &splan->paramIds);
497  splan->testexpr = convert_testexpr(root,
498  testexpr,
499  params);
500  }
501  else
502  splan->testexpr = testexpr;
503 
504  /*
505  * We can't convert subplans of ALL_SUBLINK or ANY_SUBLINK types to
506  * initPlans, even when they are uncorrelated or undirect correlated,
507  * because we need to scan the output of the subplan for each outer
508  * tuple. But if it's a not-direct-correlated IN (= ANY) test, we
509  * might be able to use a hashtable to avoid comparing all the tuples.
510  */
511  if (subLinkType == ANY_SUBLINK &&
512  splan->parParam == NIL &&
513  subplan_is_hashable(plan) &&
515  splan->useHashTable = true;
516 
517  /*
518  * Otherwise, we have the option to tack a Material node onto the top
519  * of the subplan, to reduce the cost of reading it repeatedly. This
520  * is pointless for a direct-correlated subplan, since we'd have to
521  * recompute its results each time anyway. For uncorrelated/undirect
522  * correlated subplans, we add Material unless the subplan's top plan
523  * node would materialize its output anyway. Also, if enable_material
524  * is false, then the user does not want us to materialize anything
525  * unnecessarily, so we don't.
526  */
527  else if (splan->parParam == NIL && enable_material &&
529  plan = materialize_finished_plan(plan);
530 
531  result = (Node *) splan;
532  isInitPlan = false;
533  }
534 
535  /*
536  * Add the subplan and its PlannerInfo to the global lists.
537  */
538  root->glob->subplans = lappend(root->glob->subplans, plan);
539  root->glob->subroots = lappend(root->glob->subroots, subroot);
540  splan->plan_id = list_length(root->glob->subplans);
541 
542  if (isInitPlan)
543  root->init_plans = lappend(root->init_plans, splan);
544 
545  /*
546  * A parameterless subplan (not initplan) should be prepared to handle
547  * REWIND efficiently. If it has direct parameters then there's no point
548  * since it'll be reset on each scan anyway; and if it's an initplan then
549  * there's no point since it won't get re-run without parameter changes
550  * anyway. The input of a hashed subplan doesn't need REWIND either.
551  */
552  if (splan->parParam == NIL && !isInitPlan && !splan->useHashTable)
554  splan->plan_id);
555 
556  /* Label the subplan for EXPLAIN purposes */
557  splan->plan_name = palloc(32 + 12 * list_length(splan->setParam));
558  sprintf(splan->plan_name, "%s %d",
559  isInitPlan ? "InitPlan" : "SubPlan",
560  splan->plan_id);
561  if (splan->setParam)
562  {
563  char *ptr = splan->plan_name + strlen(splan->plan_name);
564 
565  ptr += sprintf(ptr, " (returns ");
566  foreach(lc, splan->setParam)
567  {
568  ptr += sprintf(ptr, "$%d%s",
569  lfirst_int(lc),
570  lnext(splan->setParam, lc) ? "," : ")");
571  }
572  }
573 
574  /* Lastly, fill in the cost estimates for use later */
575  cost_subplan(root, splan, plan);
576 
577  return result;
578 }
579 
580 /*
581  * generate_subquery_params: build a list of Params representing the output
582  * columns of a sublink's sub-select, given the sub-select's targetlist.
583  *
584  * We also return an integer list of the paramids of the Params.
585  */
586 static List *
588 {
589  List *result;
590  List *ids;
591  ListCell *lc;
592 
593  result = ids = NIL;
594  foreach(lc, tlist)
595  {
596  TargetEntry *tent = (TargetEntry *) lfirst(lc);
597  Param *param;
598 
599  if (tent->resjunk)
600  continue;
601 
602  param = generate_new_exec_param(root,
603  exprType((Node *) tent->expr),
604  exprTypmod((Node *) tent->expr),
605  exprCollation((Node *) tent->expr));
606  result = lappend(result, param);
607  ids = lappend_int(ids, param->paramid);
608  }
609 
610  *paramIds = ids;
611  return result;
612 }
613 
614 /*
615  * generate_subquery_vars: build a list of Vars representing the output
616  * columns of a sublink's sub-select, given the sub-select's targetlist.
617  * The Vars have the specified varno (RTE index).
618  */
619 static List *
621 {
622  List *result;
623  ListCell *lc;
624 
625  result = NIL;
626  foreach(lc, tlist)
627  {
628  TargetEntry *tent = (TargetEntry *) lfirst(lc);
629  Var *var;
630 
631  if (tent->resjunk)
632  continue;
633 
634  var = makeVarFromTargetEntry(varno, tent);
635  result = lappend(result, var);
636  }
637 
638  return result;
639 }
640 
641 /*
642  * convert_testexpr: convert the testexpr given by the parser into
643  * actually executable form. This entails replacing PARAM_SUBLINK Params
644  * with Params or Vars representing the results of the sub-select. The
645  * nodes to be substituted are passed in as the List result from
646  * generate_subquery_params or generate_subquery_vars.
647  */
648 static Node *
650  Node *testexpr,
651  List *subst_nodes)
652 {
653  convert_testexpr_context context;
654 
655  context.root = root;
656  context.subst_nodes = subst_nodes;
657  return convert_testexpr_mutator(testexpr, &context);
658 }
659 
660 static Node *
662  convert_testexpr_context *context)
663 {
664  if (node == NULL)
665  return NULL;
666  if (IsA(node, Param))
667  {
668  Param *param = (Param *) node;
669 
670  if (param->paramkind == PARAM_SUBLINK)
671  {
672  if (param->paramid <= 0 ||
673  param->paramid > list_length(context->subst_nodes))
674  elog(ERROR, "unexpected PARAM_SUBLINK ID: %d", param->paramid);
675 
676  /*
677  * We copy the list item to avoid having doubly-linked
678  * substructure in the modified parse tree. This is probably
679  * unnecessary when it's a Param, but be safe.
680  */
681  return (Node *) copyObject(list_nth(context->subst_nodes,
682  param->paramid - 1));
683  }
684  }
685  if (IsA(node, SubLink))
686  {
687  /*
688  * If we come across a nested SubLink, it is neither necessary nor
689  * correct to recurse into it: any PARAM_SUBLINKs we might find inside
690  * belong to the inner SubLink not the outer. So just return it as-is.
691  *
692  * This reasoning depends on the assumption that nothing will pull
693  * subexpressions into or out of the testexpr field of a SubLink, at
694  * least not without replacing PARAM_SUBLINKs first. If we did want
695  * to do that we'd need to rethink the parser-output representation
696  * altogether, since currently PARAM_SUBLINKs are only unique per
697  * SubLink not globally across the query. The whole point of
698  * replacing them with Vars or PARAM_EXEC nodes is to make them
699  * globally unique before they escape from the SubLink's testexpr.
700  *
701  * Note: this can't happen when called during SS_process_sublinks,
702  * because that recursively processes inner SubLinks first. It can
703  * happen when called from convert_ANY_sublink_to_join, though.
704  */
705  return node;
706  }
707  return expression_tree_mutator(node,
709  (void *) context);
710 }
711 
712 /*
713  * subplan_is_hashable: can we implement an ANY subplan by hashing?
714  */
715 static bool
717 {
718  double subquery_size;
719 
720  /*
721  * The estimated size of the subquery result must fit in work_mem. (Note:
722  * we use heap tuple overhead here even though the tuples will actually be
723  * stored as MinimalTuples; this provides some fudge factor for hashtable
724  * overhead.)
725  */
726  subquery_size = plan->plan_rows *
728  if (subquery_size > work_mem * 1024L)
729  return false;
730 
731  return true;
732 }
733 
734 /*
735  * testexpr_is_hashable: is an ANY SubLink's test expression hashable?
736  */
737 static bool
739 {
740  /*
741  * The testexpr must be a single OpExpr, or an AND-clause containing only
742  * OpExprs.
743  *
744  * The combining operators must be hashable and strict. The need for
745  * hashability is obvious, since we want to use hashing. Without
746  * strictness, behavior in the presence of nulls is too unpredictable. We
747  * actually must assume even more than plain strictness: they can't yield
748  * NULL for non-null inputs, either (see nodeSubplan.c). However, hash
749  * indexes and hash joins assume that too.
750  */
751  if (testexpr && IsA(testexpr, OpExpr))
752  {
753  if (hash_ok_operator((OpExpr *) testexpr))
754  return true;
755  }
756  else if (is_andclause(testexpr))
757  {
758  ListCell *l;
759 
760  foreach(l, ((BoolExpr *) testexpr)->args)
761  {
762  Node *andarg = (Node *) lfirst(l);
763 
764  if (!IsA(andarg, OpExpr))
765  return false;
766  if (!hash_ok_operator((OpExpr *) andarg))
767  return false;
768  }
769  return true;
770  }
771 
772  return false;
773 }
774 
775 /*
776  * Check expression is hashable + strict
777  *
778  * We could use op_hashjoinable() and op_strict(), but do it like this to
779  * avoid a redundant cache lookup.
780  */
781 static bool
783 {
784  Oid opid = expr->opno;
785 
786  /* quick out if not a binary operator */
787  if (list_length(expr->args) != 2)
788  return false;
789  if (opid == ARRAY_EQ_OP)
790  {
791  /* array_eq is strict, but must check input type to ensure hashable */
792  /* XXX record_eq will need same treatment when it becomes hashable */
793  Node *leftarg = linitial(expr->args);
794 
795  return op_hashjoinable(opid, exprType(leftarg));
796  }
797  else
798  {
799  /* else must look up the operator properties */
800  HeapTuple tup;
801  Form_pg_operator optup;
802 
804  if (!HeapTupleIsValid(tup))
805  elog(ERROR, "cache lookup failed for operator %u", opid);
806  optup = (Form_pg_operator) GETSTRUCT(tup);
807  if (!optup->oprcanhash || !func_strict(optup->oprcode))
808  {
809  ReleaseSysCache(tup);
810  return false;
811  }
812  ReleaseSysCache(tup);
813  return true;
814  }
815 }
816 
817 
818 /*
819  * SS_process_ctes: process a query's WITH list
820  *
821  * Consider each CTE in the WITH list and either ignore it (if it's an
822  * unreferenced SELECT), "inline" it to create a regular sub-SELECT-in-FROM,
823  * or convert it to an initplan.
824  *
825  * A side effect is to fill in root->cte_plan_ids with a list that
826  * parallels root->parse->cteList and provides the subplan ID for
827  * each CTE's initplan, or a dummy ID (-1) if we didn't make an initplan.
828  */
829 void
831 {
832  ListCell *lc;
833 
834  Assert(root->cte_plan_ids == NIL);
835 
836  foreach(lc, root->parse->cteList)
837  {
838  CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
839  CmdType cmdType = ((Query *) cte->ctequery)->commandType;
840  Query *subquery;
841  PlannerInfo *subroot;
842  RelOptInfo *final_rel;
843  Path *best_path;
844  Plan *plan;
845  SubPlan *splan;
846  int paramid;
847 
848  /*
849  * Ignore SELECT CTEs that are not actually referenced anywhere.
850  */
851  if (cte->cterefcount == 0 && cmdType == CMD_SELECT)
852  {
853  /* Make a dummy entry in cte_plan_ids */
854  root->cte_plan_ids = lappend_int(root->cte_plan_ids, -1);
855  continue;
856  }
857 
858  /*
859  * Consider inlining the CTE (creating RTE_SUBQUERY RTE(s)) instead of
860  * implementing it as a separately-planned CTE.
861  *
862  * We cannot inline if any of these conditions hold:
863  *
864  * 1. The user said not to (the CTEMaterializeAlways option).
865  *
866  * 2. The CTE is recursive.
867  *
868  * 3. The CTE has side-effects; this includes either not being a plain
869  * SELECT, or containing volatile functions. Inlining might change
870  * the side-effects, which would be bad.
871  *
872  * 4. The CTE is multiply-referenced and contains a self-reference to
873  * a recursive CTE outside itself. Inlining would result in multiple
874  * recursive self-references, which we don't support.
875  *
876  * Otherwise, we have an option whether to inline or not. That should
877  * always be a win if there's just a single reference, but if the CTE
878  * is multiply-referenced then it's unclear: inlining adds duplicate
879  * computations, but the ability to absorb restrictions from the outer
880  * query level could outweigh that. We do not have nearly enough
881  * information at this point to tell whether that's true, so we let
882  * the user express a preference. Our default behavior is to inline
883  * only singly-referenced CTEs, but a CTE marked CTEMaterializeNever
884  * will be inlined even if multiply referenced.
885  *
886  * Note: we check for volatile functions last, because that's more
887  * expensive than the other tests needed.
888  */
889  if ((cte->ctematerialized == CTEMaterializeNever ||
891  cte->cterefcount == 1)) &&
892  !cte->cterecursive &&
893  cmdType == CMD_SELECT &&
894  !contain_dml(cte->ctequery) &&
895  (cte->cterefcount <= 1 ||
898  {
899  inline_cte(root, cte);
900  /* Make a dummy entry in cte_plan_ids */
901  root->cte_plan_ids = lappend_int(root->cte_plan_ids, -1);
902  continue;
903  }
904 
905  /*
906  * Copy the source Query node. Probably not necessary, but let's keep
907  * this similar to make_subplan.
908  */
909  subquery = (Query *) copyObject(cte->ctequery);
910 
911  /* plan_params should not be in use in current query level */
912  Assert(root->plan_params == NIL);
913 
914  /*
915  * Generate Paths for the CTE query. Always plan for full retrieval
916  * --- we don't have enough info to predict otherwise.
917  */
918  subroot = subquery_planner(root->glob, subquery,
919  root,
920  cte->cterecursive, 0.0);
921 
922  /*
923  * Since the current query level doesn't yet contain any RTEs, it
924  * should not be possible for the CTE to have requested parameters of
925  * this level.
926  */
927  if (root->plan_params)
928  elog(ERROR, "unexpected outer reference in CTE query");
929 
930  /*
931  * Select best Path and turn it into a Plan. At least for now, there
932  * seems no reason to postpone doing that.
933  */
934  final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
935  best_path = final_rel->cheapest_total_path;
936 
937  plan = create_plan(subroot, best_path);
938 
939  /*
940  * Make a SubPlan node for it. This is just enough unlike
941  * build_subplan that we can't share code.
942  *
943  * Note plan_id, plan_name, and cost fields are set further down.
944  */
945  splan = makeNode(SubPlan);
946  splan->subLinkType = CTE_SUBLINK;
947  splan->testexpr = NULL;
948  splan->paramIds = NIL;
949  get_first_col_type(plan, &splan->firstColType, &splan->firstColTypmod,
950  &splan->firstColCollation);
951  splan->useHashTable = false;
952  splan->unknownEqFalse = false;
953 
954  /*
955  * CTE scans are not considered for parallelism (cf
956  * set_rel_consider_parallel), and even if they were, initPlans aren't
957  * parallel-safe.
958  */
959  splan->parallel_safe = false;
960  splan->setParam = NIL;
961  splan->parParam = NIL;
962  splan->args = NIL;
963 
964  /*
965  * The node can't have any inputs (since it's an initplan), so the
966  * parParam and args lists remain empty. (It could contain references
967  * to earlier CTEs' output param IDs, but CTE outputs are not
968  * propagated via the args list.)
969  */
970 
971  /*
972  * Assign a param ID to represent the CTE's output. No ordinary
973  * "evaluation" of this param slot ever happens, but we use the param
974  * ID for setParam/chgParam signaling just as if the CTE plan were
975  * returning a simple scalar output. (Also, the executor abuses the
976  * ParamExecData slot for this param ID for communication among
977  * multiple CteScan nodes that might be scanning this CTE.)
978  */
979  paramid = assign_special_exec_param(root);
980  splan->setParam = list_make1_int(paramid);
981 
982  /*
983  * Add the subplan and its PlannerInfo to the global lists.
984  */
985  root->glob->subplans = lappend(root->glob->subplans, plan);
986  root->glob->subroots = lappend(root->glob->subroots, subroot);
987  splan->plan_id = list_length(root->glob->subplans);
988 
989  root->init_plans = lappend(root->init_plans, splan);
990 
991  root->cte_plan_ids = lappend_int(root->cte_plan_ids, splan->plan_id);
992 
993  /* Label the subplan for EXPLAIN purposes */
994  splan->plan_name = psprintf("CTE %s", cte->ctename);
995 
996  /* Lastly, fill in the cost estimates for use later */
997  cost_subplan(root, splan, plan);
998  }
999 }
1000 
1001 /*
1002  * contain_dml: is any subquery not a plain SELECT?
1003  *
1004  * We reject SELECT FOR UPDATE/SHARE as well as INSERT etc.
1005  */
1006 static bool
1008 {
1009  return contain_dml_walker(node, NULL);
1010 }
1011 
1012 static bool
1013 contain_dml_walker(Node *node, void *context)
1014 {
1015  if (node == NULL)
1016  return false;
1017  if (IsA(node, Query))
1018  {
1019  Query *query = (Query *) node;
1020 
1021  if (query->commandType != CMD_SELECT ||
1022  query->rowMarks != NIL)
1023  return true;
1024 
1025  return query_tree_walker(query, contain_dml_walker, context, 0);
1026  }
1027  return expression_tree_walker(node, contain_dml_walker, context);
1028 }
1029 
1030 /*
1031  * contain_outer_selfref: is there an external recursive self-reference?
1032  */
1033 static bool
1035 {
1036  Index depth = 0;
1037 
1038  /*
1039  * We should be starting with a Query, so that depth will be 1 while
1040  * examining its immediate contents.
1041  */
1042  Assert(IsA(node, Query));
1043 
1044  return contain_outer_selfref_walker(node, &depth);
1045 }
1046 
1047 static bool
1049 {
1050  if (node == NULL)
1051  return false;
1052  if (IsA(node, RangeTblEntry))
1053  {
1054  RangeTblEntry *rte = (RangeTblEntry *) node;
1055 
1056  /*
1057  * Check for a self-reference to a CTE that's above the Query that our
1058  * search started at.
1059  */
1060  if (rte->rtekind == RTE_CTE &&
1061  rte->self_reference &&
1062  rte->ctelevelsup >= *depth)
1063  return true;
1064  return false; /* allow range_table_walker to continue */
1065  }
1066  if (IsA(node, Query))
1067  {
1068  /* Recurse into subquery, tracking nesting depth properly */
1069  Query *query = (Query *) node;
1070  bool result;
1071 
1072  (*depth)++;
1073 
1075  (void *) depth, QTW_EXAMINE_RTES_BEFORE);
1076 
1077  (*depth)--;
1078 
1079  return result;
1080  }
1082  (void *) depth);
1083 }
1084 
1085 /*
1086  * inline_cte: convert RTE_CTE references to given CTE into RTE_SUBQUERYs
1087  */
1088 static void
1090 {
1091  struct inline_cte_walker_context context;
1092 
1093  context.ctename = cte->ctename;
1094  /* Start at levelsup = -1 because we'll immediately increment it */
1095  context.levelsup = -1;
1096  context.refcount = cte->cterefcount;
1097  context.ctequery = castNode(Query, cte->ctequery);
1098 
1099  (void) inline_cte_walker((Node *) root->parse, &context);
1100 
1101  /* Assert we replaced all references */
1102  Assert(context.refcount == 0);
1103 }
1104 
1105 static bool
1107 {
1108  if (node == NULL)
1109  return false;
1110  if (IsA(node, Query))
1111  {
1112  Query *query = (Query *) node;
1113 
1114  context->levelsup++;
1115 
1116  /*
1117  * Visit the query's RTE nodes after their contents; otherwise
1118  * query_tree_walker would descend into the newly inlined CTE query,
1119  * which we don't want.
1120  */
1121  (void) query_tree_walker(query, inline_cte_walker, context,
1123 
1124  context->levelsup--;
1125 
1126  return false;
1127  }
1128  else if (IsA(node, RangeTblEntry))
1129  {
1130  RangeTblEntry *rte = (RangeTblEntry *) node;
1131 
1132  if (rte->rtekind == RTE_CTE &&
1133  strcmp(rte->ctename, context->ctename) == 0 &&
1134  rte->ctelevelsup == context->levelsup)
1135  {
1136  /*
1137  * Found a reference to replace. Generate a copy of the CTE query
1138  * with appropriate level adjustment for outer references (e.g.,
1139  * to other CTEs).
1140  */
1141  Query *newquery = copyObject(context->ctequery);
1142 
1143  if (context->levelsup > 0)
1144  IncrementVarSublevelsUp((Node *) newquery, context->levelsup, 1);
1145 
1146  /*
1147  * Convert the RTE_CTE RTE into a RTE_SUBQUERY.
1148  *
1149  * Historically, a FOR UPDATE clause has been treated as extending
1150  * into views and subqueries, but not into CTEs. We preserve this
1151  * distinction by not trying to push rowmarks into the new
1152  * subquery.
1153  */
1154  rte->rtekind = RTE_SUBQUERY;
1155  rte->subquery = newquery;
1156  rte->security_barrier = false;
1157 
1158  /* Zero out CTE-specific fields */
1159  rte->ctename = NULL;
1160  rte->ctelevelsup = 0;
1161  rte->self_reference = false;
1162  rte->coltypes = NIL;
1163  rte->coltypmods = NIL;
1164  rte->colcollations = NIL;
1165 
1166  /* Count the number of replacements we've done */
1167  context->refcount--;
1168  }
1169 
1170  return false;
1171  }
1172 
1173  return expression_tree_walker(node, inline_cte_walker, context);
1174 }
1175 
1176 
1177 /*
1178  * convert_ANY_sublink_to_join: try to convert an ANY SubLink to a join
1179  *
1180  * The caller has found an ANY SubLink at the top level of one of the query's
1181  * qual clauses, but has not checked the properties of the SubLink further.
1182  * Decide whether it is appropriate to process this SubLink in join style.
1183  * If so, form a JoinExpr and return it. Return NULL if the SubLink cannot
1184  * be converted to a join.
1185  *
1186  * The only non-obvious input parameter is available_rels: this is the set
1187  * of query rels that can safely be referenced in the sublink expression.
1188  * (We must restrict this to avoid changing the semantics when a sublink
1189  * is present in an outer join's ON qual.) The conversion must fail if
1190  * the converted qual would reference any but these parent-query relids.
1191  *
1192  * On success, the returned JoinExpr has larg = NULL and rarg = the jointree
1193  * item representing the pulled-up subquery. The caller must set larg to
1194  * represent the relation(s) on the lefthand side of the new join, and insert
1195  * the JoinExpr into the upper query's jointree at an appropriate place
1196  * (typically, where the lefthand relation(s) had been). Note that the
1197  * passed-in SubLink must also be removed from its original position in the
1198  * query quals, since the quals of the returned JoinExpr replace it.
1199  * (Notionally, we replace the SubLink with a constant TRUE, then elide the
1200  * redundant constant from the qual.)
1201  *
1202  * On success, the caller is also responsible for recursively applying
1203  * pull_up_sublinks processing to the rarg and quals of the returned JoinExpr.
1204  * (On failure, there is no need to do anything, since pull_up_sublinks will
1205  * be applied when we recursively plan the sub-select.)
1206  *
1207  * Side effects of a successful conversion include adding the SubLink's
1208  * subselect to the query's rangetable, so that it can be referenced in
1209  * the JoinExpr's rarg.
1210  */
1211 JoinExpr *
1213  Relids available_rels)
1214 {
1215  JoinExpr *result;
1216  Query *parse = root->parse;
1217  Query *subselect = (Query *) sublink->subselect;
1218  Relids upper_varnos;
1219  int rtindex;
1220  RangeTblEntry *rte;
1221  RangeTblRef *rtr;
1222  List *subquery_vars;
1223  Node *quals;
1224  ParseState *pstate;
1225 
1226  Assert(sublink->subLinkType == ANY_SUBLINK);
1227 
1228  /*
1229  * The sub-select must not refer to any Vars of the parent query. (Vars of
1230  * higher levels should be okay, though.)
1231  */
1232  if (contain_vars_of_level((Node *) subselect, 1))
1233  return NULL;
1234 
1235  /*
1236  * The test expression must contain some Vars of the parent query, else
1237  * it's not gonna be a join. (Note that it won't have Vars referring to
1238  * the subquery, rather Params.)
1239  */
1240  upper_varnos = pull_varnos(sublink->testexpr);
1241  if (bms_is_empty(upper_varnos))
1242  return NULL;
1243 
1244  /*
1245  * However, it can't refer to anything outside available_rels.
1246  */
1247  if (!bms_is_subset(upper_varnos, available_rels))
1248  return NULL;
1249 
1250  /*
1251  * The combining operators and left-hand expressions mustn't be volatile.
1252  */
1253  if (contain_volatile_functions(sublink->testexpr))
1254  return NULL;
1255 
1256  /* Create a dummy ParseState for addRangeTableEntryForSubquery */
1257  pstate = make_parsestate(NULL);
1258 
1259  /*
1260  * Okay, pull up the sub-select into upper range table.
1261  *
1262  * We rely here on the assumption that the outer query has no references
1263  * to the inner (necessarily true, other than the Vars that we build
1264  * below). Therefore this is a lot easier than what pull_up_subqueries has
1265  * to go through.
1266  */
1267  rte = addRangeTableEntryForSubquery(pstate,
1268  subselect,
1269  makeAlias("ANY_subquery", NIL),
1270  false,
1271  false);
1272  parse->rtable = lappend(parse->rtable, rte);
1273  rtindex = list_length(parse->rtable);
1274 
1275  /*
1276  * Form a RangeTblRef for the pulled-up sub-select.
1277  */
1278  rtr = makeNode(RangeTblRef);
1279  rtr->rtindex = rtindex;
1280 
1281  /*
1282  * Build a list of Vars representing the subselect outputs.
1283  */
1284  subquery_vars = generate_subquery_vars(root,
1285  subselect->targetList,
1286  rtindex);
1287 
1288  /*
1289  * Build the new join's qual expression, replacing Params with these Vars.
1290  */
1291  quals = convert_testexpr(root, sublink->testexpr, subquery_vars);
1292 
1293  /*
1294  * And finally, build the JoinExpr node.
1295  */
1296  result = makeNode(JoinExpr);
1297  result->jointype = JOIN_SEMI;
1298  result->isNatural = false;
1299  result->larg = NULL; /* caller must fill this in */
1300  result->rarg = (Node *) rtr;
1301  result->usingClause = NIL;
1302  result->quals = quals;
1303  result->alias = NULL;
1304  result->rtindex = 0; /* we don't need an RTE for it */
1305 
1306  return result;
1307 }
1308 
1309 /*
1310  * convert_EXISTS_sublink_to_join: try to convert an EXISTS SubLink to a join
1311  *
1312  * The API of this function is identical to convert_ANY_sublink_to_join's,
1313  * except that we also support the case where the caller has found NOT EXISTS,
1314  * so we need an additional input parameter "under_not".
1315  */
1316 JoinExpr *
1318  bool under_not, Relids available_rels)
1319 {
1320  JoinExpr *result;
1321  Query *parse = root->parse;
1322  Query *subselect = (Query *) sublink->subselect;
1323  Node *whereClause;
1324  int rtoffset;
1325  int varno;
1326  Relids clause_varnos;
1327  Relids upper_varnos;
1328 
1329  Assert(sublink->subLinkType == EXISTS_SUBLINK);
1330 
1331  /*
1332  * Can't flatten if it contains WITH. (We could arrange to pull up the
1333  * WITH into the parent query's cteList, but that risks changing the
1334  * semantics, since a WITH ought to be executed once per associated query
1335  * call.) Note that convert_ANY_sublink_to_join doesn't have to reject
1336  * this case, since it just produces a subquery RTE that doesn't have to
1337  * get flattened into the parent query.
1338  */
1339  if (subselect->cteList)
1340  return NULL;
1341 
1342  /*
1343  * Copy the subquery so we can modify it safely (see comments in
1344  * make_subplan).
1345  */
1346  subselect = copyObject(subselect);
1347 
1348  /*
1349  * See if the subquery can be simplified based on the knowledge that it's
1350  * being used in EXISTS(). If we aren't able to get rid of its
1351  * targetlist, we have to fail, because the pullup operation leaves us
1352  * with noplace to evaluate the targetlist.
1353  */
1354  if (!simplify_EXISTS_query(root, subselect))
1355  return NULL;
1356 
1357  /*
1358  * Separate out the WHERE clause. (We could theoretically also remove
1359  * top-level plain JOIN/ON clauses, but it's probably not worth the
1360  * trouble.)
1361  */
1362  whereClause = subselect->jointree->quals;
1363  subselect->jointree->quals = NULL;
1364 
1365  /*
1366  * The rest of the sub-select must not refer to any Vars of the parent
1367  * query. (Vars of higher levels should be okay, though.)
1368  */
1369  if (contain_vars_of_level((Node *) subselect, 1))
1370  return NULL;
1371 
1372  /*
1373  * On the other hand, the WHERE clause must contain some Vars of the
1374  * parent query, else it's not gonna be a join.
1375  */
1376  if (!contain_vars_of_level(whereClause, 1))
1377  return NULL;
1378 
1379  /*
1380  * We don't risk optimizing if the WHERE clause is volatile, either.
1381  */
1382  if (contain_volatile_functions(whereClause))
1383  return NULL;
1384 
1385  /*
1386  * The subquery must have a nonempty jointree, but we can make it so.
1387  */
1388  replace_empty_jointree(subselect);
1389 
1390  /*
1391  * Prepare to pull up the sub-select into top range table.
1392  *
1393  * We rely here on the assumption that the outer query has no references
1394  * to the inner (necessarily true). Therefore this is a lot easier than
1395  * what pull_up_subqueries has to go through.
1396  *
1397  * In fact, it's even easier than what convert_ANY_sublink_to_join has to
1398  * do. The machinations of simplify_EXISTS_query ensured that there is
1399  * nothing interesting in the subquery except an rtable and jointree, and
1400  * even the jointree FromExpr no longer has quals. So we can just append
1401  * the rtable to our own and use the FromExpr in our jointree. But first,
1402  * adjust all level-zero varnos in the subquery to account for the rtable
1403  * merger.
1404  */
1405  rtoffset = list_length(parse->rtable);
1406  OffsetVarNodes((Node *) subselect, rtoffset, 0);
1407  OffsetVarNodes(whereClause, rtoffset, 0);
1408 
1409  /*
1410  * Upper-level vars in subquery will now be one level closer to their
1411  * parent than before; in particular, anything that had been level 1
1412  * becomes level zero.
1413  */
1414  IncrementVarSublevelsUp((Node *) subselect, -1, 1);
1415  IncrementVarSublevelsUp(whereClause, -1, 1);
1416 
1417  /*
1418  * Now that the WHERE clause is adjusted to match the parent query
1419  * environment, we can easily identify all the level-zero rels it uses.
1420  * The ones <= rtoffset belong to the upper query; the ones > rtoffset do
1421  * not.
1422  */
1423  clause_varnos = pull_varnos(whereClause);
1424  upper_varnos = NULL;
1425  while ((varno = bms_first_member(clause_varnos)) >= 0)
1426  {
1427  if (varno <= rtoffset)
1428  upper_varnos = bms_add_member(upper_varnos, varno);
1429  }
1430  bms_free(clause_varnos);
1431  Assert(!bms_is_empty(upper_varnos));
1432 
1433  /*
1434  * Now that we've got the set of upper-level varnos, we can make the last
1435  * check: only available_rels can be referenced.
1436  */
1437  if (!bms_is_subset(upper_varnos, available_rels))
1438  return NULL;
1439 
1440  /* Now we can attach the modified subquery rtable to the parent */
1441  parse->rtable = list_concat(parse->rtable, subselect->rtable);
1442 
1443  /*
1444  * And finally, build the JoinExpr node.
1445  */
1446  result = makeNode(JoinExpr);
1447  result->jointype = under_not ? JOIN_ANTI : JOIN_SEMI;
1448  result->isNatural = false;
1449  result->larg = NULL; /* caller must fill this in */
1450  /* flatten out the FromExpr node if it's useless */
1451  if (list_length(subselect->jointree->fromlist) == 1)
1452  result->rarg = (Node *) linitial(subselect->jointree->fromlist);
1453  else
1454  result->rarg = (Node *) subselect->jointree;
1455  result->usingClause = NIL;
1456  result->quals = whereClause;
1457  result->alias = NULL;
1458  result->rtindex = 0; /* we don't need an RTE for it */
1459 
1460  return result;
1461 }
1462 
1463 /*
1464  * simplify_EXISTS_query: remove any useless stuff in an EXISTS's subquery
1465  *
1466  * The only thing that matters about an EXISTS query is whether it returns
1467  * zero or more than zero rows. Therefore, we can remove certain SQL features
1468  * that won't affect that. The only part that is really likely to matter in
1469  * typical usage is simplifying the targetlist: it's a common habit to write
1470  * "SELECT * FROM" even though there is no need to evaluate any columns.
1471  *
1472  * Note: by suppressing the targetlist we could cause an observable behavioral
1473  * change, namely that any errors that might occur in evaluating the tlist
1474  * won't occur, nor will other side-effects of volatile functions. This seems
1475  * unlikely to bother anyone in practice.
1476  *
1477  * Returns true if was able to discard the targetlist, else false.
1478  */
1479 static bool
1481 {
1482  /*
1483  * We don't try to simplify at all if the query uses set operations,
1484  * aggregates, grouping sets, SRFs, modifying CTEs, HAVING, OFFSET, or FOR
1485  * UPDATE/SHARE; none of these seem likely in normal usage and their
1486  * possible effects are complex. (Note: we could ignore an "OFFSET 0"
1487  * clause, but that traditionally is used as an optimization fence, so we
1488  * don't.)
1489  */
1490  if (query->commandType != CMD_SELECT ||
1491  query->setOperations ||
1492  query->hasAggs ||
1493  query->groupingSets ||
1494  query->hasWindowFuncs ||
1495  query->hasTargetSRFs ||
1496  query->hasModifyingCTE ||
1497  query->havingQual ||
1498  query->limitOffset ||
1499  query->rowMarks)
1500  return false;
1501 
1502  /*
1503  * LIMIT with a constant positive (or NULL) value doesn't affect the
1504  * semantics of EXISTS, so let's ignore such clauses. This is worth doing
1505  * because people accustomed to certain other DBMSes may be in the habit
1506  * of writing EXISTS(SELECT ... LIMIT 1) as an optimization. If there's a
1507  * LIMIT with anything else as argument, though, we can't simplify.
1508  */
1509  if (query->limitCount)
1510  {
1511  /*
1512  * The LIMIT clause has not yet been through eval_const_expressions,
1513  * so we have to apply that here. It might seem like this is a waste
1514  * of cycles, since the only case plausibly worth worrying about is
1515  * "LIMIT 1" ... but what we'll actually see is "LIMIT int8(1::int4)",
1516  * so we have to fold constants or we're not going to recognize it.
1517  */
1518  Node *node = eval_const_expressions(root, query->limitCount);
1519  Const *limit;
1520 
1521  /* Might as well update the query if we simplified the clause. */
1522  query->limitCount = node;
1523 
1524  if (!IsA(node, Const))
1525  return false;
1526 
1527  limit = (Const *) node;
1528  Assert(limit->consttype == INT8OID);
1529  if (!limit->constisnull && DatumGetInt64(limit->constvalue) <= 0)
1530  return false;
1531 
1532  /* Whether or not the targetlist is safe, we can drop the LIMIT. */
1533  query->limitCount = NULL;
1534  }
1535 
1536  /*
1537  * Otherwise, we can throw away the targetlist, as well as any GROUP,
1538  * WINDOW, DISTINCT, and ORDER BY clauses; none of those clauses will
1539  * change a nonzero-rows result to zero rows or vice versa. (Furthermore,
1540  * since our parsetree representation of these clauses depends on the
1541  * targetlist, we'd better throw them away if we drop the targetlist.)
1542  */
1543  query->targetList = NIL;
1544  query->groupClause = NIL;
1545  query->windowClause = NIL;
1546  query->distinctClause = NIL;
1547  query->sortClause = NIL;
1548  query->hasDistinctOn = false;
1549 
1550  return true;
1551 }
1552 
1553 /*
1554  * convert_EXISTS_to_ANY: try to convert EXISTS to a hashable ANY sublink
1555  *
1556  * The subselect is expected to be a fresh copy that we can munge up,
1557  * and to have been successfully passed through simplify_EXISTS_query.
1558  *
1559  * On success, the modified subselect is returned, and we store a suitable
1560  * upper-level test expression at *testexpr, plus a list of the subselect's
1561  * output Params at *paramIds. (The test expression is already Param-ified
1562  * and hence need not go through convert_testexpr, which is why we have to
1563  * deal with the Param IDs specially.)
1564  *
1565  * On failure, returns NULL.
1566  */
1567 static Query *
1569  Node **testexpr, List **paramIds)
1570 {
1571  Node *whereClause;
1572  List *leftargs,
1573  *rightargs,
1574  *opids,
1575  *opcollations,
1576  *newWhere,
1577  *tlist,
1578  *testlist,
1579  *paramids;
1580  ListCell *lc,
1581  *rc,
1582  *oc,
1583  *cc;
1584  AttrNumber resno;
1585 
1586  /*
1587  * Query must not require a targetlist, since we have to insert a new one.
1588  * Caller should have dealt with the case already.
1589  */
1590  Assert(subselect->targetList == NIL);
1591 
1592  /*
1593  * Separate out the WHERE clause. (We could theoretically also remove
1594  * top-level plain JOIN/ON clauses, but it's probably not worth the
1595  * trouble.)
1596  */
1597  whereClause = subselect->jointree->quals;
1598  subselect->jointree->quals = NULL;
1599 
1600  /*
1601  * The rest of the sub-select must not refer to any Vars of the parent
1602  * query. (Vars of higher levels should be okay, though.)
1603  *
1604  * Note: we need not check for Aggrefs separately because we know the
1605  * sub-select is as yet unoptimized; any uplevel Aggref must therefore
1606  * contain an uplevel Var reference. This is not the case below ...
1607  */
1608  if (contain_vars_of_level((Node *) subselect, 1))
1609  return NULL;
1610 
1611  /*
1612  * We don't risk optimizing if the WHERE clause is volatile, either.
1613  */
1614  if (contain_volatile_functions(whereClause))
1615  return NULL;
1616 
1617  /*
1618  * Clean up the WHERE clause by doing const-simplification etc on it.
1619  * Aside from simplifying the processing we're about to do, this is
1620  * important for being able to pull chunks of the WHERE clause up into the
1621  * parent query. Since we are invoked partway through the parent's
1622  * preprocess_expression() work, earlier steps of preprocess_expression()
1623  * wouldn't get applied to the pulled-up stuff unless we do them here. For
1624  * the parts of the WHERE clause that get put back into the child query,
1625  * this work is partially duplicative, but it shouldn't hurt.
1626  *
1627  * Note: we do not run flatten_join_alias_vars. This is OK because any
1628  * parent aliases were flattened already, and we're not going to pull any
1629  * child Vars (of any description) into the parent.
1630  *
1631  * Note: passing the parent's root to eval_const_expressions is
1632  * technically wrong, but we can get away with it since only the
1633  * boundParams (if any) are used, and those would be the same in a
1634  * subroot.
1635  */
1636  whereClause = eval_const_expressions(root, whereClause);
1637  whereClause = (Node *) canonicalize_qual((Expr *) whereClause, false);
1638  whereClause = (Node *) make_ands_implicit((Expr *) whereClause);
1639 
1640  /*
1641  * We now have a flattened implicit-AND list of clauses, which we try to
1642  * break apart into "outervar = innervar" hash clauses. Anything that
1643  * can't be broken apart just goes back into the newWhere list. Note that
1644  * we aren't trying hard yet to ensure that we have only outer or only
1645  * inner on each side; we'll check that if we get to the end.
1646  */
1647  leftargs = rightargs = opids = opcollations = newWhere = NIL;
1648  foreach(lc, (List *) whereClause)
1649  {
1650  OpExpr *expr = (OpExpr *) lfirst(lc);
1651 
1652  if (IsA(expr, OpExpr) &&
1653  hash_ok_operator(expr))
1654  {
1655  Node *leftarg = (Node *) linitial(expr->args);
1656  Node *rightarg = (Node *) lsecond(expr->args);
1657 
1658  if (contain_vars_of_level(leftarg, 1))
1659  {
1660  leftargs = lappend(leftargs, leftarg);
1661  rightargs = lappend(rightargs, rightarg);
1662  opids = lappend_oid(opids, expr->opno);
1663  opcollations = lappend_oid(opcollations, expr->inputcollid);
1664  continue;
1665  }
1666  if (contain_vars_of_level(rightarg, 1))
1667  {
1668  /*
1669  * We must commute the clause to put the outer var on the
1670  * left, because the hashing code in nodeSubplan.c expects
1671  * that. This probably shouldn't ever fail, since hashable
1672  * operators ought to have commutators, but be paranoid.
1673  */
1674  expr->opno = get_commutator(expr->opno);
1675  if (OidIsValid(expr->opno) && hash_ok_operator(expr))
1676  {
1677  leftargs = lappend(leftargs, rightarg);
1678  rightargs = lappend(rightargs, leftarg);
1679  opids = lappend_oid(opids, expr->opno);
1680  opcollations = lappend_oid(opcollations, expr->inputcollid);
1681  continue;
1682  }
1683  /* If no commutator, no chance to optimize the WHERE clause */
1684  return NULL;
1685  }
1686  }
1687  /* Couldn't handle it as a hash clause */
1688  newWhere = lappend(newWhere, expr);
1689  }
1690 
1691  /*
1692  * If we didn't find anything we could convert, fail.
1693  */
1694  if (leftargs == NIL)
1695  return NULL;
1696 
1697  /*
1698  * There mustn't be any parent Vars or Aggs in the stuff that we intend to
1699  * put back into the child query. Note: you might think we don't need to
1700  * check for Aggs separately, because an uplevel Agg must contain an
1701  * uplevel Var in its argument. But it is possible that the uplevel Var
1702  * got optimized away by eval_const_expressions. Consider
1703  *
1704  * SUM(CASE WHEN false THEN uplevelvar ELSE 0 END)
1705  */
1706  if (contain_vars_of_level((Node *) newWhere, 1) ||
1707  contain_vars_of_level((Node *) rightargs, 1))
1708  return NULL;
1709  if (root->parse->hasAggs &&
1710  (contain_aggs_of_level((Node *) newWhere, 1) ||
1711  contain_aggs_of_level((Node *) rightargs, 1)))
1712  return NULL;
1713 
1714  /*
1715  * And there can't be any child Vars in the stuff we intend to pull up.
1716  * (Note: we'd need to check for child Aggs too, except we know the child
1717  * has no aggs at all because of simplify_EXISTS_query's check. The same
1718  * goes for window functions.)
1719  */
1720  if (contain_vars_of_level((Node *) leftargs, 0))
1721  return NULL;
1722 
1723  /*
1724  * Also reject sublinks in the stuff we intend to pull up. (It might be
1725  * possible to support this, but doesn't seem worth the complication.)
1726  */
1727  if (contain_subplans((Node *) leftargs))
1728  return NULL;
1729 
1730  /*
1731  * Okay, adjust the sublevelsup in the stuff we're pulling up.
1732  */
1733  IncrementVarSublevelsUp((Node *) leftargs, -1, 1);
1734 
1735  /*
1736  * Put back any child-level-only WHERE clauses.
1737  */
1738  if (newWhere)
1739  subselect->jointree->quals = (Node *) make_ands_explicit(newWhere);
1740 
1741  /*
1742  * Build a new targetlist for the child that emits the expressions we
1743  * need. Concurrently, build a testexpr for the parent using Params to
1744  * reference the child outputs. (Since we generate Params directly here,
1745  * there will be no need to convert the testexpr in build_subplan.)
1746  */
1747  tlist = testlist = paramids = NIL;
1748  resno = 1;
1749  forfour(lc, leftargs, rc, rightargs, oc, opids, cc, opcollations)
1750  {
1751  Node *leftarg = (Node *) lfirst(lc);
1752  Node *rightarg = (Node *) lfirst(rc);
1753  Oid opid = lfirst_oid(oc);
1754  Oid opcollation = lfirst_oid(cc);
1755  Param *param;
1756 
1757  param = generate_new_exec_param(root,
1758  exprType(rightarg),
1759  exprTypmod(rightarg),
1760  exprCollation(rightarg));
1761  tlist = lappend(tlist,
1762  makeTargetEntry((Expr *) rightarg,
1763  resno++,
1764  NULL,
1765  false));
1766  testlist = lappend(testlist,
1767  make_opclause(opid, BOOLOID, false,
1768  (Expr *) leftarg, (Expr *) param,
1769  InvalidOid, opcollation));
1770  paramids = lappend_int(paramids, param->paramid);
1771  }
1772 
1773  /* Put everything where it should go, and we're done */
1774  subselect->targetList = tlist;
1775  *testexpr = (Node *) make_ands_explicit(testlist);
1776  *paramIds = paramids;
1777 
1778  return subselect;
1779 }
1780 
1781 
1782 /*
1783  * Replace correlation vars (uplevel vars) with Params.
1784  *
1785  * Uplevel PlaceHolderVars and aggregates are replaced, too.
1786  *
1787  * Note: it is critical that this runs immediately after SS_process_sublinks.
1788  * Since we do not recurse into the arguments of uplevel PHVs and aggregates,
1789  * they will get copied to the appropriate subplan args list in the parent
1790  * query with uplevel vars not replaced by Params, but only adjusted in level
1791  * (see replace_outer_placeholdervar and replace_outer_agg). That's exactly
1792  * what we want for the vars of the parent level --- but if a PHV's or
1793  * aggregate's argument contains any further-up variables, they have to be
1794  * replaced with Params in their turn. That will happen when the parent level
1795  * runs SS_replace_correlation_vars. Therefore it must do so after expanding
1796  * its sublinks to subplans. And we don't want any steps in between, else
1797  * those steps would never get applied to the argument expressions, either in
1798  * the parent or the child level.
1799  *
1800  * Another fairly tricky thing going on here is the handling of SubLinks in
1801  * the arguments of uplevel PHVs/aggregates. Those are not touched inside the
1802  * intermediate query level, either. Instead, SS_process_sublinks recurses on
1803  * them after copying the PHV or Aggref expression into the parent plan level
1804  * (this is actually taken care of in build_subplan).
1805  */
1806 Node *
1808 {
1809  /* No setup needed for tree walk, so away we go */
1810  return replace_correlation_vars_mutator(expr, root);
1811 }
1812 
1813 static Node *
1815 {
1816  if (node == NULL)
1817  return NULL;
1818  if (IsA(node, Var))
1819  {
1820  if (((Var *) node)->varlevelsup > 0)
1821  return (Node *) replace_outer_var(root, (Var *) node);
1822  }
1823  if (IsA(node, PlaceHolderVar))
1824  {
1825  if (((PlaceHolderVar *) node)->phlevelsup > 0)
1826  return (Node *) replace_outer_placeholdervar(root,
1827  (PlaceHolderVar *) node);
1828  }
1829  if (IsA(node, Aggref))
1830  {
1831  if (((Aggref *) node)->agglevelsup > 0)
1832  return (Node *) replace_outer_agg(root, (Aggref *) node);
1833  }
1834  if (IsA(node, GroupingFunc))
1835  {
1836  if (((GroupingFunc *) node)->agglevelsup > 0)
1837  return (Node *) replace_outer_grouping(root, (GroupingFunc *) node);
1838  }
1839  return expression_tree_mutator(node,
1841  (void *) root);
1842 }
1843 
1844 /*
1845  * Expand SubLinks to SubPlans in the given expression.
1846  *
1847  * The isQual argument tells whether or not this expression is a WHERE/HAVING
1848  * qualifier expression. If it is, any sublinks appearing at top level need
1849  * not distinguish FALSE from UNKNOWN return values.
1850  */
1851 Node *
1853 {
1854  process_sublinks_context context;
1855 
1856  context.root = root;
1857  context.isTopQual = isQual;
1858  return process_sublinks_mutator(expr, &context);
1859 }
1860 
1861 static Node *
1863 {
1864  process_sublinks_context locContext;
1865 
1866  locContext.root = context->root;
1867 
1868  if (node == NULL)
1869  return NULL;
1870  if (IsA(node, SubLink))
1871  {
1872  SubLink *sublink = (SubLink *) node;
1873  Node *testexpr;
1874 
1875  /*
1876  * First, recursively process the lefthand-side expressions, if any.
1877  * They're not top-level anymore.
1878  */
1879  locContext.isTopQual = false;
1880  testexpr = process_sublinks_mutator(sublink->testexpr, &locContext);
1881 
1882  /*
1883  * Now build the SubPlan node and make the expr to return.
1884  */
1885  return make_subplan(context->root,
1886  (Query *) sublink->subselect,
1887  sublink->subLinkType,
1888  sublink->subLinkId,
1889  testexpr,
1890  context->isTopQual);
1891  }
1892 
1893  /*
1894  * Don't recurse into the arguments of an outer PHV or aggregate here. Any
1895  * SubLinks in the arguments have to be dealt with at the outer query
1896  * level; they'll be handled when build_subplan collects the PHV or Aggref
1897  * into the arguments to be passed down to the current subplan.
1898  */
1899  if (IsA(node, PlaceHolderVar))
1900  {
1901  if (((PlaceHolderVar *) node)->phlevelsup > 0)
1902  return node;
1903  }
1904  else if (IsA(node, Aggref))
1905  {
1906  if (((Aggref *) node)->agglevelsup > 0)
1907  return node;
1908  }
1909 
1910  /*
1911  * We should never see a SubPlan expression in the input (since this is
1912  * the very routine that creates 'em to begin with). We shouldn't find
1913  * ourselves invoked directly on a Query, either.
1914  */
1915  Assert(!IsA(node, SubPlan));
1916  Assert(!IsA(node, AlternativeSubPlan));
1917  Assert(!IsA(node, Query));
1918 
1919  /*
1920  * Because make_subplan() could return an AND or OR clause, we have to
1921  * take steps to preserve AND/OR flatness of a qual. We assume the input
1922  * has been AND/OR flattened and so we need no recursion here.
1923  *
1924  * (Due to the coding here, we will not get called on the List subnodes of
1925  * an AND; and the input is *not* yet in implicit-AND format. So no check
1926  * is needed for a bare List.)
1927  *
1928  * Anywhere within the top-level AND/OR clause structure, we can tell
1929  * make_subplan() that NULL and FALSE are interchangeable. So isTopQual
1930  * propagates down in both cases. (Note that this is unlike the meaning
1931  * of "top level qual" used in most other places in Postgres.)
1932  */
1933  if (is_andclause(node))
1934  {
1935  List *newargs = NIL;
1936  ListCell *l;
1937 
1938  /* Still at qual top-level */
1939  locContext.isTopQual = context->isTopQual;
1940 
1941  foreach(l, ((BoolExpr *) node)->args)
1942  {
1943  Node *newarg;
1944 
1945  newarg = process_sublinks_mutator(lfirst(l), &locContext);
1946  if (is_andclause(newarg))
1947  newargs = list_concat(newargs, ((BoolExpr *) newarg)->args);
1948  else
1949  newargs = lappend(newargs, newarg);
1950  }
1951  return (Node *) make_andclause(newargs);
1952  }
1953 
1954  if (is_orclause(node))
1955  {
1956  List *newargs = NIL;
1957  ListCell *l;
1958 
1959  /* Still at qual top-level */
1960  locContext.isTopQual = context->isTopQual;
1961 
1962  foreach(l, ((BoolExpr *) node)->args)
1963  {
1964  Node *newarg;
1965 
1966  newarg = process_sublinks_mutator(lfirst(l), &locContext);
1967  if (is_orclause(newarg))
1968  newargs = list_concat(newargs, ((BoolExpr *) newarg)->args);
1969  else
1970  newargs = lappend(newargs, newarg);
1971  }
1972  return (Node *) make_orclause(newargs);
1973  }
1974 
1975  /*
1976  * If we recurse down through anything other than an AND or OR node, we
1977  * are definitely not at top qual level anymore.
1978  */
1979  locContext.isTopQual = false;
1980 
1981  return expression_tree_mutator(node,
1983  (void *) &locContext);
1984 }
1985 
1986 /*
1987  * SS_identify_outer_params - identify the Params available from outer levels
1988  *
1989  * This must be run after SS_replace_correlation_vars and SS_process_sublinks
1990  * processing is complete in a given query level as well as all of its
1991  * descendant levels (which means it's most practical to do it at the end of
1992  * processing the query level). We compute the set of paramIds that outer
1993  * levels will make available to this level+descendants, and record it in
1994  * root->outer_params for use while computing extParam/allParam sets in final
1995  * plan cleanup. (We can't just compute it then, because the upper levels'
1996  * plan_params lists are transient and will be gone by then.)
1997  */
1998 void
2000 {
2001  Bitmapset *outer_params;
2002  PlannerInfo *proot;
2003  ListCell *l;
2004 
2005  /*
2006  * If no parameters have been assigned anywhere in the tree, we certainly
2007  * don't need to do anything here.
2008  */
2009  if (root->glob->paramExecTypes == NIL)
2010  return;
2011 
2012  /*
2013  * Scan all query levels above this one to see which parameters are due to
2014  * be available from them, either because lower query levels have
2015  * requested them (via plan_params) or because they will be available from
2016  * initPlans of those levels.
2017  */
2018  outer_params = NULL;
2019  for (proot = root->parent_root; proot != NULL; proot = proot->parent_root)
2020  {
2021  /* Include ordinary Var/PHV/Aggref params */
2022  foreach(l, proot->plan_params)
2023  {
2024  PlannerParamItem *pitem = (PlannerParamItem *) lfirst(l);
2025 
2026  outer_params = bms_add_member(outer_params, pitem->paramId);
2027  }
2028  /* Include any outputs of outer-level initPlans */
2029  foreach(l, proot->init_plans)
2030  {
2031  SubPlan *initsubplan = (SubPlan *) lfirst(l);
2032  ListCell *l2;
2033 
2034  foreach(l2, initsubplan->setParam)
2035  {
2036  outer_params = bms_add_member(outer_params, lfirst_int(l2));
2037  }
2038  }
2039  /* Include worktable ID, if a recursive query is being planned */
2040  if (proot->wt_param_id >= 0)
2041  outer_params = bms_add_member(outer_params, proot->wt_param_id);
2042  }
2043  root->outer_params = outer_params;
2044 }
2045 
2046 /*
2047  * SS_charge_for_initplans - account for initplans in Path costs & parallelism
2048  *
2049  * If any initPlans have been created in the current query level, they will
2050  * get attached to the Plan tree created from whichever Path we select from
2051  * the given rel. Increment all that rel's Paths' costs to account for them,
2052  * and make sure the paths get marked as parallel-unsafe, since we can't
2053  * currently transmit initPlans to parallel workers.
2054  *
2055  * This is separate from SS_attach_initplans because we might conditionally
2056  * create more initPlans during create_plan(), depending on which Path we
2057  * select. However, Paths that would generate such initPlans are expected
2058  * to have included their cost already.
2059  */
2060 void
2062 {
2063  Cost initplan_cost;
2064  ListCell *lc;
2065 
2066  /* Nothing to do if no initPlans */
2067  if (root->init_plans == NIL)
2068  return;
2069 
2070  /*
2071  * Compute the cost increment just once, since it will be the same for all
2072  * Paths. We assume each initPlan gets run once during top plan startup.
2073  * This is a conservative overestimate, since in fact an initPlan might be
2074  * executed later than plan startup, or even not at all.
2075  */
2076  initplan_cost = 0;
2077  foreach(lc, root->init_plans)
2078  {
2079  SubPlan *initsubplan = (SubPlan *) lfirst(lc);
2080 
2081  initplan_cost += initsubplan->startup_cost + initsubplan->per_call_cost;
2082  }
2083 
2084  /*
2085  * Now adjust the costs and parallel_safe flags.
2086  */
2087  foreach(lc, final_rel->pathlist)
2088  {
2089  Path *path = (Path *) lfirst(lc);
2090 
2091  path->startup_cost += initplan_cost;
2092  path->total_cost += initplan_cost;
2093  path->parallel_safe = false;
2094  }
2095 
2096  /*
2097  * Forget about any partial paths and clear consider_parallel, too;
2098  * they're not usable if we attached an initPlan.
2099  */
2100  final_rel->partial_pathlist = NIL;
2101  final_rel->consider_parallel = false;
2102 
2103  /* We needn't do set_cheapest() here, caller will do it */
2104 }
2105 
2106 /*
2107  * SS_attach_initplans - attach initplans to topmost plan node
2108  *
2109  * Attach any initplans created in the current query level to the specified
2110  * plan node, which should normally be the topmost node for the query level.
2111  * (In principle the initPlans could go in any node at or above where they're
2112  * referenced; but there seems no reason to put them any lower than the
2113  * topmost node, so we don't bother to track exactly where they came from.)
2114  * We do not touch the plan node's cost; the initplans should have been
2115  * accounted for in path costing.
2116  */
2117 void
2119 {
2120  plan->initPlan = root->init_plans;
2121 }
2122 
2123 /*
2124  * SS_finalize_plan - do final parameter processing for a completed Plan.
2125  *
2126  * This recursively computes the extParam and allParam sets for every Plan
2127  * node in the given plan tree. (Oh, and RangeTblFunction.funcparams too.)
2128  *
2129  * We assume that SS_finalize_plan has already been run on any initplans or
2130  * subplans the plan tree could reference.
2131  */
2132 void
2134 {
2135  /* No setup needed, just recurse through plan tree. */
2136  (void) finalize_plan(root, plan, -1, root->outer_params, NULL);
2137 }
2138 
2139 /*
2140  * Recursive processing of all nodes in the plan tree
2141  *
2142  * gather_param is the rescan_param of an ancestral Gather/GatherMerge,
2143  * or -1 if there is none.
2144  *
2145  * valid_params is the set of param IDs supplied by outer plan levels
2146  * that are valid to reference in this plan node or its children.
2147  *
2148  * scan_params is a set of param IDs to force scan plan nodes to reference.
2149  * This is for EvalPlanQual support, and is always NULL at the top of the
2150  * recursion.
2151  *
2152  * The return value is the computed allParam set for the given Plan node.
2153  * This is just an internal notational convenience: we can add a child
2154  * plan's allParams to the set of param IDs of interest to this level
2155  * in the same statement that recurses to that child.
2156  *
2157  * Do not scribble on caller's values of valid_params or scan_params!
2158  *
2159  * Note: although we attempt to deal with initPlans anywhere in the tree, the
2160  * logic is not really right. The problem is that a plan node might return an
2161  * output Param of its initPlan as a targetlist item, in which case it's valid
2162  * for the parent plan level to reference that same Param; the parent's usage
2163  * will be converted into a Var referencing the child plan node by setrefs.c.
2164  * But this function would see the parent's reference as out of scope and
2165  * complain about it. For now, this does not matter because the planner only
2166  * attaches initPlans to the topmost plan node in a query level, so the case
2167  * doesn't arise. If we ever merge this processing into setrefs.c, maybe it
2168  * can be handled more cleanly.
2169  */
2170 static Bitmapset *
2172  int gather_param,
2173  Bitmapset *valid_params,
2174  Bitmapset *scan_params)
2175 {
2176  finalize_primnode_context context;
2177  int locally_added_param;
2178  Bitmapset *nestloop_params;
2179  Bitmapset *initExtParam;
2180  Bitmapset *initSetParam;
2181  Bitmapset *child_params;
2182  ListCell *l;
2183 
2184  if (plan == NULL)
2185  return NULL;
2186 
2187  context.root = root;
2188  context.paramids = NULL; /* initialize set to empty */
2189  locally_added_param = -1; /* there isn't one */
2190  nestloop_params = NULL; /* there aren't any */
2191 
2192  /*
2193  * Examine any initPlans to determine the set of external params they
2194  * reference and the set of output params they supply. (We assume
2195  * SS_finalize_plan was run on them already.)
2196  */
2197  initExtParam = initSetParam = NULL;
2198  foreach(l, plan->initPlan)
2199  {
2200  SubPlan *initsubplan = (SubPlan *) lfirst(l);
2201  Plan *initplan = planner_subplan_get_plan(root, initsubplan);
2202  ListCell *l2;
2203 
2204  initExtParam = bms_add_members(initExtParam, initplan->extParam);
2205  foreach(l2, initsubplan->setParam)
2206  {
2207  initSetParam = bms_add_member(initSetParam, lfirst_int(l2));
2208  }
2209  }
2210 
2211  /* Any setParams are validly referenceable in this node and children */
2212  if (initSetParam)
2213  valid_params = bms_union(valid_params, initSetParam);
2214 
2215  /*
2216  * When we call finalize_primnode, context.paramids sets are automatically
2217  * merged together. But when recursing to self, we have to do it the hard
2218  * way. We want the paramids set to include params in subplans as well as
2219  * at this level.
2220  */
2221 
2222  /* Find params in targetlist and qual */
2223  finalize_primnode((Node *) plan->targetlist, &context);
2224  finalize_primnode((Node *) plan->qual, &context);
2225 
2226  /*
2227  * If it's a parallel-aware scan node, mark it as dependent on the parent
2228  * Gather/GatherMerge's rescan Param.
2229  */
2230  if (plan->parallel_aware)
2231  {
2232  if (gather_param < 0)
2233  elog(ERROR, "parallel-aware plan node is not below a Gather");
2234  context.paramids =
2235  bms_add_member(context.paramids, gather_param);
2236  }
2237 
2238  /* Check additional node-type-specific fields */
2239  switch (nodeTag(plan))
2240  {
2241  case T_Result:
2242  finalize_primnode(((Result *) plan)->resconstantqual,
2243  &context);
2244  break;
2245 
2246  case T_SeqScan:
2247  context.paramids = bms_add_members(context.paramids, scan_params);
2248  break;
2249 
2250  case T_SampleScan:
2251  finalize_primnode((Node *) ((SampleScan *) plan)->tablesample,
2252  &context);
2253  context.paramids = bms_add_members(context.paramids, scan_params);
2254  break;
2255 
2256  case T_IndexScan:
2257  finalize_primnode((Node *) ((IndexScan *) plan)->indexqual,
2258  &context);
2259  finalize_primnode((Node *) ((IndexScan *) plan)->indexorderby,
2260  &context);
2261 
2262  /*
2263  * we need not look at indexqualorig, since it will have the same
2264  * param references as indexqual. Likewise, we can ignore
2265  * indexorderbyorig.
2266  */
2267  context.paramids = bms_add_members(context.paramids, scan_params);
2268  break;
2269 
2270  case T_IndexOnlyScan:
2271  finalize_primnode((Node *) ((IndexOnlyScan *) plan)->indexqual,
2272  &context);
2273  finalize_primnode((Node *) ((IndexOnlyScan *) plan)->indexorderby,
2274  &context);
2275 
2276  /*
2277  * we need not look at indextlist, since it cannot contain Params.
2278  */
2279  context.paramids = bms_add_members(context.paramids, scan_params);
2280  break;
2281 
2282  case T_BitmapIndexScan:
2283  finalize_primnode((Node *) ((BitmapIndexScan *) plan)->indexqual,
2284  &context);
2285 
2286  /*
2287  * we need not look at indexqualorig, since it will have the same
2288  * param references as indexqual.
2289  */
2290  break;
2291 
2292  case T_BitmapHeapScan:
2293  finalize_primnode((Node *) ((BitmapHeapScan *) plan)->bitmapqualorig,
2294  &context);
2295  context.paramids = bms_add_members(context.paramids, scan_params);
2296  break;
2297 
2298  case T_TidScan:
2299  finalize_primnode((Node *) ((TidScan *) plan)->tidquals,
2300  &context);
2301  context.paramids = bms_add_members(context.paramids, scan_params);
2302  break;
2303 
2304  case T_SubqueryScan:
2305  {
2306  SubqueryScan *sscan = (SubqueryScan *) plan;
2307  RelOptInfo *rel;
2308  Bitmapset *subquery_params;
2309 
2310  /* We must run finalize_plan on the subquery */
2311  rel = find_base_rel(root, sscan->scan.scanrelid);
2312  subquery_params = rel->subroot->outer_params;
2313  if (gather_param >= 0)
2314  subquery_params = bms_add_member(bms_copy(subquery_params),
2315  gather_param);
2316  finalize_plan(rel->subroot, sscan->subplan, gather_param,
2317  subquery_params, NULL);
2318 
2319  /* Now we can add its extParams to the parent's params */
2320  context.paramids = bms_add_members(context.paramids,
2321  sscan->subplan->extParam);
2322  /* We need scan_params too, though */
2323  context.paramids = bms_add_members(context.paramids,
2324  scan_params);
2325  }
2326  break;
2327 
2328  case T_FunctionScan:
2329  {
2330  FunctionScan *fscan = (FunctionScan *) plan;
2331  ListCell *lc;
2332 
2333  /*
2334  * Call finalize_primnode independently on each function
2335  * expression, so that we can record which params are
2336  * referenced in each, in order to decide which need
2337  * re-evaluating during rescan.
2338  */
2339  foreach(lc, fscan->functions)
2340  {
2341  RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc);
2342  finalize_primnode_context funccontext;
2343 
2344  funccontext = context;
2345  funccontext.paramids = NULL;
2346 
2347  finalize_primnode(rtfunc->funcexpr, &funccontext);
2348 
2349  /* remember results for execution */
2350  rtfunc->funcparams = funccontext.paramids;
2351 
2352  /* add the function's params to the overall set */
2353  context.paramids = bms_add_members(context.paramids,
2354  funccontext.paramids);
2355  }
2356 
2357  context.paramids = bms_add_members(context.paramids,
2358  scan_params);
2359  }
2360  break;
2361 
2362  case T_TableFuncScan:
2363  finalize_primnode((Node *) ((TableFuncScan *) plan)->tablefunc,
2364  &context);
2365  context.paramids = bms_add_members(context.paramids, scan_params);
2366  break;
2367 
2368  case T_ValuesScan:
2369  finalize_primnode((Node *) ((ValuesScan *) plan)->values_lists,
2370  &context);
2371  context.paramids = bms_add_members(context.paramids, scan_params);
2372  break;
2373 
2374  case T_CteScan:
2375  {
2376  /*
2377  * You might think we should add the node's cteParam to
2378  * paramids, but we shouldn't because that param is just a
2379  * linkage mechanism for multiple CteScan nodes for the same
2380  * CTE; it is never used for changed-param signaling. What we
2381  * have to do instead is to find the referenced CTE plan and
2382  * incorporate its external paramids, so that the correct
2383  * things will happen if the CTE references outer-level
2384  * variables. See test cases for bug #4902. (We assume
2385  * SS_finalize_plan was run on the CTE plan already.)
2386  */
2387  int plan_id = ((CteScan *) plan)->ctePlanId;
2388  Plan *cteplan;
2389 
2390  /* so, do this ... */
2391  if (plan_id < 1 || plan_id > list_length(root->glob->subplans))
2392  elog(ERROR, "could not find plan for CteScan referencing plan ID %d",
2393  plan_id);
2394  cteplan = (Plan *) list_nth(root->glob->subplans, plan_id - 1);
2395  context.paramids =
2396  bms_add_members(context.paramids, cteplan->extParam);
2397 
2398 #ifdef NOT_USED
2399  /* ... but not this */
2400  context.paramids =
2401  bms_add_member(context.paramids,
2402  ((CteScan *) plan)->cteParam);
2403 #endif
2404 
2405  context.paramids = bms_add_members(context.paramids,
2406  scan_params);
2407  }
2408  break;
2409 
2410  case T_WorkTableScan:
2411  context.paramids =
2412  bms_add_member(context.paramids,
2413  ((WorkTableScan *) plan)->wtParam);
2414  context.paramids = bms_add_members(context.paramids, scan_params);
2415  break;
2416 
2417  case T_NamedTuplestoreScan:
2418  context.paramids = bms_add_members(context.paramids, scan_params);
2419  break;
2420 
2421  case T_ForeignScan:
2422  {
2423  ForeignScan *fscan = (ForeignScan *) plan;
2424 
2425  finalize_primnode((Node *) fscan->fdw_exprs,
2426  &context);
2428  &context);
2429 
2430  /* We assume fdw_scan_tlist cannot contain Params */
2431  context.paramids = bms_add_members(context.paramids,
2432  scan_params);
2433  }
2434  break;
2435 
2436  case T_CustomScan:
2437  {
2438  CustomScan *cscan = (CustomScan *) plan;
2439  ListCell *lc;
2440 
2441  finalize_primnode((Node *) cscan->custom_exprs,
2442  &context);
2443  /* We assume custom_scan_tlist cannot contain Params */
2444  context.paramids =
2445  bms_add_members(context.paramids, scan_params);
2446 
2447  /* child nodes if any */
2448  foreach(lc, cscan->custom_plans)
2449  {
2450  context.paramids =
2451  bms_add_members(context.paramids,
2452  finalize_plan(root,
2453  (Plan *) lfirst(lc),
2454  gather_param,
2455  valid_params,
2456  scan_params));
2457  }
2458  }
2459  break;
2460 
2461  case T_ModifyTable:
2462  {
2463  ModifyTable *mtplan = (ModifyTable *) plan;
2464  ListCell *l;
2465 
2466  /* Force descendant scan nodes to reference epqParam */
2467  locally_added_param = mtplan->epqParam;
2468  valid_params = bms_add_member(bms_copy(valid_params),
2469  locally_added_param);
2470  scan_params = bms_add_member(bms_copy(scan_params),
2471  locally_added_param);
2473  &context);
2474  finalize_primnode((Node *) mtplan->onConflictSet,
2475  &context);
2477  &context);
2478  /* exclRelTlist contains only Vars, doesn't need examination */
2479  foreach(l, mtplan->plans)
2480  {
2481  context.paramids =
2482  bms_add_members(context.paramids,
2483  finalize_plan(root,
2484  (Plan *) lfirst(l),
2485  gather_param,
2486  valid_params,
2487  scan_params));
2488  }
2489  }
2490  break;
2491 
2492  case T_Append:
2493  {
2494  ListCell *l;
2495 
2496  foreach(l, ((Append *) plan)->appendplans)
2497  {
2498  context.paramids =
2499  bms_add_members(context.paramids,
2500  finalize_plan(root,
2501  (Plan *) lfirst(l),
2502  gather_param,
2503  valid_params,
2504  scan_params));
2505  }
2506  }
2507  break;
2508 
2509  case T_MergeAppend:
2510  {
2511  ListCell *l;
2512 
2513  foreach(l, ((MergeAppend *) plan)->mergeplans)
2514  {
2515  context.paramids =
2516  bms_add_members(context.paramids,
2517  finalize_plan(root,
2518  (Plan *) lfirst(l),
2519  gather_param,
2520  valid_params,
2521  scan_params));
2522  }
2523  }
2524  break;
2525 
2526  case T_BitmapAnd:
2527  {
2528  ListCell *l;
2529 
2530  foreach(l, ((BitmapAnd *) plan)->bitmapplans)
2531  {
2532  context.paramids =
2533  bms_add_members(context.paramids,
2534  finalize_plan(root,
2535  (Plan *) lfirst(l),
2536  gather_param,
2537  valid_params,
2538  scan_params));
2539  }
2540  }
2541  break;
2542 
2543  case T_BitmapOr:
2544  {
2545  ListCell *l;
2546 
2547  foreach(l, ((BitmapOr *) plan)->bitmapplans)
2548  {
2549  context.paramids =
2550  bms_add_members(context.paramids,
2551  finalize_plan(root,
2552  (Plan *) lfirst(l),
2553  gather_param,
2554  valid_params,
2555  scan_params));
2556  }
2557  }
2558  break;
2559 
2560  case T_NestLoop:
2561  {
2562  ListCell *l;
2563 
2564  finalize_primnode((Node *) ((Join *) plan)->joinqual,
2565  &context);
2566  /* collect set of params that will be passed to right child */
2567  foreach(l, ((NestLoop *) plan)->nestParams)
2568  {
2569  NestLoopParam *nlp = (NestLoopParam *) lfirst(l);
2570 
2571  nestloop_params = bms_add_member(nestloop_params,
2572  nlp->paramno);
2573  }
2574  }
2575  break;
2576 
2577  case T_MergeJoin:
2578  finalize_primnode((Node *) ((Join *) plan)->joinqual,
2579  &context);
2580  finalize_primnode((Node *) ((MergeJoin *) plan)->mergeclauses,
2581  &context);
2582  break;
2583 
2584  case T_HashJoin:
2585  finalize_primnode((Node *) ((Join *) plan)->joinqual,
2586  &context);
2587  finalize_primnode((Node *) ((HashJoin *) plan)->hashclauses,
2588  &context);
2589  break;
2590 
2591  case T_Limit:
2592  finalize_primnode(((Limit *) plan)->limitOffset,
2593  &context);
2594  finalize_primnode(((Limit *) plan)->limitCount,
2595  &context);
2596  break;
2597 
2598  case T_RecursiveUnion:
2599  /* child nodes are allowed to reference wtParam */
2600  locally_added_param = ((RecursiveUnion *) plan)->wtParam;
2601  valid_params = bms_add_member(bms_copy(valid_params),
2602  locally_added_param);
2603  /* wtParam does *not* get added to scan_params */
2604  break;
2605 
2606  case T_LockRows:
2607  /* Force descendant scan nodes to reference epqParam */
2608  locally_added_param = ((LockRows *) plan)->epqParam;
2609  valid_params = bms_add_member(bms_copy(valid_params),
2610  locally_added_param);
2611  scan_params = bms_add_member(bms_copy(scan_params),
2612  locally_added_param);
2613  break;
2614 
2615  case T_Agg:
2616  {
2617  Agg *agg = (Agg *) plan;
2618 
2619  /*
2620  * AGG_HASHED plans need to know which Params are referenced
2621  * in aggregate calls. Do a separate scan to identify them.
2622  */
2623  if (agg->aggstrategy == AGG_HASHED)
2624  {
2625  finalize_primnode_context aggcontext;
2626 
2627  aggcontext.root = root;
2628  aggcontext.paramids = NULL;
2630  &aggcontext);
2632  &aggcontext);
2633  agg->aggParams = aggcontext.paramids;
2634  }
2635  }
2636  break;
2637 
2638  case T_WindowAgg:
2639  finalize_primnode(((WindowAgg *) plan)->startOffset,
2640  &context);
2641  finalize_primnode(((WindowAgg *) plan)->endOffset,
2642  &context);
2643  break;
2644 
2645  case T_Gather:
2646  /* child nodes are allowed to reference rescan_param, if any */
2647  locally_added_param = ((Gather *) plan)->rescan_param;
2648  if (locally_added_param >= 0)
2649  {
2650  valid_params = bms_add_member(bms_copy(valid_params),
2651  locally_added_param);
2652 
2653  /*
2654  * We currently don't support nested Gathers. The issue so
2655  * far as this function is concerned would be how to identify
2656  * which child nodes depend on which Gather.
2657  */
2658  Assert(gather_param < 0);
2659  /* Pass down rescan_param to child parallel-aware nodes */
2660  gather_param = locally_added_param;
2661  }
2662  /* rescan_param does *not* get added to scan_params */
2663  break;
2664 
2665  case T_GatherMerge:
2666  /* child nodes are allowed to reference rescan_param, if any */
2667  locally_added_param = ((GatherMerge *) plan)->rescan_param;
2668  if (locally_added_param >= 0)
2669  {
2670  valid_params = bms_add_member(bms_copy(valid_params),
2671  locally_added_param);
2672 
2673  /*
2674  * We currently don't support nested Gathers. The issue so
2675  * far as this function is concerned would be how to identify
2676  * which child nodes depend on which Gather.
2677  */
2678  Assert(gather_param < 0);
2679  /* Pass down rescan_param to child parallel-aware nodes */
2680  gather_param = locally_added_param;
2681  }
2682  /* rescan_param does *not* get added to scan_params */
2683  break;
2684 
2685  case T_ProjectSet:
2686  case T_Hash:
2687  case T_Material:
2688  case T_Sort:
2689  case T_Unique:
2690  case T_SetOp:
2691  case T_Group:
2692  /* no node-type-specific fields need fixing */
2693  break;
2694 
2695  default:
2696  elog(ERROR, "unrecognized node type: %d",
2697  (int) nodeTag(plan));
2698  }
2699 
2700  /* Process left and right child plans, if any */
2701  child_params = finalize_plan(root,
2702  plan->lefttree,
2703  gather_param,
2704  valid_params,
2705  scan_params);
2706  context.paramids = bms_add_members(context.paramids, child_params);
2707 
2708  if (nestloop_params)
2709  {
2710  /* right child can reference nestloop_params as well as valid_params */
2711  child_params = finalize_plan(root,
2712  plan->righttree,
2713  gather_param,
2714  bms_union(nestloop_params, valid_params),
2715  scan_params);
2716  /* ... and they don't count as parameters used at my level */
2717  child_params = bms_difference(child_params, nestloop_params);
2718  bms_free(nestloop_params);
2719  }
2720  else
2721  {
2722  /* easy case */
2723  child_params = finalize_plan(root,
2724  plan->righttree,
2725  gather_param,
2726  valid_params,
2727  scan_params);
2728  }
2729  context.paramids = bms_add_members(context.paramids, child_params);
2730 
2731  /*
2732  * Any locally generated parameter doesn't count towards its generating
2733  * plan node's external dependencies. (Note: if we changed valid_params
2734  * and/or scan_params, we leak those bitmapsets; not worth the notational
2735  * trouble to clean them up.)
2736  */
2737  if (locally_added_param >= 0)
2738  {
2739  context.paramids = bms_del_member(context.paramids,
2740  locally_added_param);
2741  }
2742 
2743  /* Now we have all the paramids referenced in this node and children */
2744 
2745  if (!bms_is_subset(context.paramids, valid_params))
2746  elog(ERROR, "plan should not reference subplan's variable");
2747 
2748  /*
2749  * The plan node's allParam and extParam fields should include all its
2750  * referenced paramids, plus contributions from any child initPlans.
2751  * However, any setParams of the initPlans should not be present in the
2752  * parent node's extParams, only in its allParams. (It's possible that
2753  * some initPlans have extParams that are setParams of other initPlans.)
2754  */
2755 
2756  /* allParam must include initplans' extParams and setParams */
2757  plan->allParam = bms_union(context.paramids, initExtParam);
2758  plan->allParam = bms_add_members(plan->allParam, initSetParam);
2759  /* extParam must include any initplan extParams */
2760  plan->extParam = bms_union(context.paramids, initExtParam);
2761  /* but not any initplan setParams */
2762  plan->extParam = bms_del_members(plan->extParam, initSetParam);
2763 
2764  /*
2765  * For speed at execution time, make sure extParam/allParam are actually
2766  * NULL if they are empty sets.
2767  */
2768  if (bms_is_empty(plan->extParam))
2769  plan->extParam = NULL;
2770  if (bms_is_empty(plan->allParam))
2771  plan->allParam = NULL;
2772 
2773  return plan->allParam;
2774 }
2775 
2776 /*
2777  * finalize_primnode: add IDs of all PARAM_EXEC params appearing in the given
2778  * expression tree to the result set.
2779  */
2780 static bool
2782 {
2783  if (node == NULL)
2784  return false;
2785  if (IsA(node, Param))
2786  {
2787  if (((Param *) node)->paramkind == PARAM_EXEC)
2788  {
2789  int paramid = ((Param *) node)->paramid;
2790 
2791  context->paramids = bms_add_member(context->paramids, paramid);
2792  }
2793  return false; /* no more to do here */
2794  }
2795  if (IsA(node, SubPlan))
2796  {
2797  SubPlan *subplan = (SubPlan *) node;
2798  Plan *plan = planner_subplan_get_plan(context->root, subplan);
2799  ListCell *lc;
2800  Bitmapset *subparamids;
2801 
2802  /* Recurse into the testexpr, but not into the Plan */
2803  finalize_primnode(subplan->testexpr, context);
2804 
2805  /*
2806  * Remove any param IDs of output parameters of the subplan that were
2807  * referenced in the testexpr. These are not interesting for
2808  * parameter change signaling since we always re-evaluate the subplan.
2809  * Note that this wouldn't work too well if there might be uses of the
2810  * same param IDs elsewhere in the plan, but that can't happen because
2811  * generate_new_exec_param never tries to merge params.
2812  */
2813  foreach(lc, subplan->paramIds)
2814  {
2815  context->paramids = bms_del_member(context->paramids,
2816  lfirst_int(lc));
2817  }
2818 
2819  /* Also examine args list */
2820  finalize_primnode((Node *) subplan->args, context);
2821 
2822  /*
2823  * Add params needed by the subplan to paramids, but excluding those
2824  * we will pass down to it. (We assume SS_finalize_plan was run on
2825  * the subplan already.)
2826  */
2827  subparamids = bms_copy(plan->extParam);
2828  foreach(lc, subplan->parParam)
2829  {
2830  subparamids = bms_del_member(subparamids, lfirst_int(lc));
2831  }
2832  context->paramids = bms_join(context->paramids, subparamids);
2833 
2834  return false; /* no more to do here */
2835  }
2837  (void *) context);
2838 }
2839 
2840 /*
2841  * finalize_agg_primnode: find all Aggref nodes in the given expression tree,
2842  * and add IDs of all PARAM_EXEC params appearing within their aggregated
2843  * arguments to the result set.
2844  */
2845 static bool
2847 {
2848  if (node == NULL)
2849  return false;
2850  if (IsA(node, Aggref))
2851  {
2852  Aggref *agg = (Aggref *) node;
2853 
2854  /* we should not consider the direct arguments, if any */
2855  finalize_primnode((Node *) agg->args, context);
2856  finalize_primnode((Node *) agg->aggfilter, context);
2857  return false; /* there can't be any Aggrefs below here */
2858  }
2860  (void *) context);
2861 }
2862 
2863 /*
2864  * SS_make_initplan_output_param - make a Param for an initPlan's output
2865  *
2866  * The plan is expected to return a scalar value of the given type/collation.
2867  *
2868  * Note that in some cases the initplan may not ever appear in the finished
2869  * plan tree. If that happens, we'll have wasted a PARAM_EXEC slot, which
2870  * is no big deal.
2871  */
2872 Param *
2874  Oid resulttype, int32 resulttypmod,
2875  Oid resultcollation)
2876 {
2877  return generate_new_exec_param(root, resulttype,
2878  resulttypmod, resultcollation);
2879 }
2880 
2881 /*
2882  * SS_make_initplan_from_plan - given a plan tree, make it an InitPlan
2883  *
2884  * We build an EXPR_SUBLINK SubPlan node and put it into the initplan
2885  * list for the outer query level. A Param that represents the initplan's
2886  * output has already been assigned using SS_make_initplan_output_param.
2887  */
2888 void
2890  PlannerInfo *subroot, Plan *plan,
2891  Param *prm)
2892 {
2893  SubPlan *node;
2894 
2895  /*
2896  * Add the subplan and its PlannerInfo to the global lists.
2897  */
2898  root->glob->subplans = lappend(root->glob->subplans, plan);
2899  root->glob->subroots = lappend(root->glob->subroots, subroot);
2900 
2901  /*
2902  * Create a SubPlan node and add it to the outer list of InitPlans. Note
2903  * it has to appear after any other InitPlans it might depend on (see
2904  * comments in ExecReScan).
2905  */
2906  node = makeNode(SubPlan);
2907  node->subLinkType = EXPR_SUBLINK;
2908  node->plan_id = list_length(root->glob->subplans);
2909  node->plan_name = psprintf("InitPlan %d (returns $%d)",
2910  node->plan_id, prm->paramid);
2911  get_first_col_type(plan, &node->firstColType, &node->firstColTypmod,
2912  &node->firstColCollation);
2913  node->setParam = list_make1_int(prm->paramid);
2914 
2915  root->init_plans = lappend(root->init_plans, node);
2916 
2917  /*
2918  * The node can't have any inputs (since it's an initplan), so the
2919  * parParam and args lists remain empty.
2920  */
2921 
2922  /* Set costs of SubPlan using info from the plan tree */
2923  cost_subplan(subroot, node, plan);
2924 }
Datum constvalue
Definition: primnodes.h:200
#define list_make2(x1, x2)
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static Node * convert_testexpr(PlannerInfo *root, Node *testexpr, List *subst_nodes)
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Index scanrelid
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SubLinkType
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int paramid
Definition: primnodes.h:249
void cost_subplan(PlannerInfo *root, SubPlan *subplan, Plan *plan)
Definition: costsize.c:3619
Bitmapset * outer_params
Definition: pathnodes.h:192
bool unknownEqFalse
Definition: primnodes.h:706
Bitmapset * bms_union(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:225
Oid exprType(const Node *expr)
Definition: nodeFuncs.c:41
const char * ctename
Definition: subselect.c:62
bool expression_tree_walker(Node *node, bool(*walker)(), void *context)
Definition: nodeFuncs.c:1839
static int list_length(const List *l)
Definition: pg_list.h:169
Node * SS_replace_correlation_vars(PlannerInfo *root, Node *expr)
Definition: subselect.c:1807
Oid exprCollation(const Node *expr)
Definition: nodeFuncs.c:719
void SS_attach_initplans(PlannerInfo *root, Plan *plan)
Definition: subselect.c:2118
List * subroots
Definition: pathnodes.h:113
Expr * aggfilter
Definition: primnodes.h:308
Bitmapset * extParam
Definition: plannodes.h:158
Index ctelevelsup
Definition: parsenodes.h:1057
#define MAXALIGN(LEN)
Definition: c.h:692
Bitmapset * funcparams
Definition: parsenodes.h:1133
List * parParam
Definition: primnodes.h:715
Oid inputcollid
Definition: primnodes.h:507
bool consider_parallel
Definition: pathnodes.h:649
Bitmapset * bms_add_member(Bitmapset *a, int x)
Definition: bitmapset.c:736
void SS_make_initplan_from_plan(PlannerInfo *root, PlannerInfo *subroot, Plan *plan, Param *prm)
Definition: subselect.c:2889
struct Plan * lefttree
Definition: plannodes.h:142
FormData_pg_operator * Form_pg_operator
Definition: pg_operator.h:83
bool func_strict(Oid funcid)
Definition: lsyscache.c:1563
bool parallel_safe
Definition: primnodes.h:709
#define nodeTag(nodeptr)
Definition: nodes.h:530
List * targetlist
Definition: plannodes.h:140
bool contain_aggs_of_level(Node *node, int levelsup)
Definition: rewriteManip.c:67
#define forfour(cell1, list1, cell2, list2, cell3, list3, cell4, list4)
Definition: pg_list.h:476
Bitmapset * bms_del_members(Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:928
RTEKind rtekind
Definition: parsenodes.h:974
Definition: nodes.h:84
char * ctename
Definition: parsenodes.h:1056
List * cteList
Definition: parsenodes.h:135
Node * setOperations
Definition: parsenodes.h:165
Query * subquery
Definition: parsenodes.h:1009
List * groupClause
Definition: parsenodes.h:148
void * palloc(Size size)
Definition: mcxt.c:949
List * initPlan
Definition: plannodes.h:144
Definition: nodes.h:81
#define elog(elevel,...)
Definition: elog.h:228
bool hasModifyingCTE
Definition: parsenodes.h:131
void * arg
bool ExecMaterializesOutput(NodeTag plantype)
Definition: execAmi.c:609
bool useHashTable
Definition: primnodes.h:704
List * returningLists
Definition: plannodes.h:229
bool parallel_safe
Definition: plannodes.h:134
Oid firstColCollation
Definition: primnodes.h:701
Cost startup_cost
Definition: primnodes.h:718
List * pathlist
Definition: pathnodes.h:655
Oid opno
Definition: primnodes.h:502
Definition: plannodes.h:802
RelOptInfo * find_base_rel(PlannerInfo *root, int relid)
Definition: relnode.c:363
#define copyObject(obj)
Definition: nodes.h:641
List * args
Definition: primnodes.h:508
Node * havingQual
Definition: parsenodes.h:152
List * coltypes
Definition: parsenodes.h:1078
void SS_finalize_plan(PlannerInfo *root, Plan *plan)
Definition: subselect.c:2133
Bitmapset * bms_del_member(Bitmapset *a, int x)
Definition: bitmapset.c:773
Param * replace_outer_grouping(PlannerInfo *root, GroupingFunc *grp)
Definition: paramassign.c:270
struct finalize_primnode_context finalize_primnode_context
int rtindex
Definition: primnodes.h:1481
Definition: pg_list.h:50
int16 AttrNumber
Definition: attnum.h:21
PlannerInfo * subquery_planner(PlannerGlobal *glob, Query *parse, PlannerInfo *parent_root, bool hasRecursion, double tuple_fraction)
Definition: planner.c:595
CmdType
Definition: nodes.h:668
static Node * replace_correlation_vars_mutator(Node *node, PlannerInfo *root)
Definition: subselect.c:1814
bool constisnull
Definition: primnodes.h:201
static bool inline_cte_walker(Node *node, inline_cte_walker_context *context)
Definition: subselect.c:1106
double Cost
Definition: nodes.h:659
Bitmapset * bms_add_members(Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:793
Plan * subplan
Definition: plannodes.h:511
Path * get_cheapest_fractional_path(RelOptInfo *rel, double tuple_fraction)
Definition: planner.c:5886
#define lfirst_oid(lc)
Definition: pg_list.h:192
static bool contain_outer_selfref_walker(Node *node, Index *depth)
Definition: subselect.c:1048
static struct subre * parse(struct vars *, int, int, struct state *, struct state *)
Definition: regcomp.c:648
int epqParam
Definition: plannodes.h:233
Node * onConflictWhere
Definition: plannodes.h:237
bool enable_material
Definition: costsize.c:132
Param * replace_outer_agg(PlannerInfo *root, Aggref *agg)
Definition: paramassign.c:224
Definition: nodes.h:86
List * args
Definition: primnodes.h:716