1 /*-------------------------------------------------------------------------
4 * Planning routines for subselects and parameters.
6 * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
10 * $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.147 2009/03/10 22:09:26 tgl Exp $
12 *-------------------------------------------------------------------------
16 #include "catalog/pg_operator.h"
17 #include "catalog/pg_type.h"
18 #include "miscadmin.h"
19 #include "nodes/makefuncs.h"
20 #include "nodes/nodeFuncs.h"
21 #include "optimizer/clauses.h"
22 #include "optimizer/cost.h"
23 #include "optimizer/planmain.h"
24 #include "optimizer/planner.h"
25 #include "optimizer/prep.h"
26 #include "optimizer/subselect.h"
27 #include "optimizer/var.h"
28 #include "parser/parse_relation.h"
29 #include "parser/parsetree.h"
30 #include "rewrite/rewriteManip.h"
31 #include "utils/builtins.h"
32 #include "utils/lsyscache.h"
33 #include "utils/syscache.h"
36 typedef struct convert_testexpr_context
39 List *subst_nodes; /* Nodes to substitute for Params */
40 } convert_testexpr_context;
42 typedef struct process_sublinks_context
46 } process_sublinks_context;
48 typedef struct finalize_primnode_context
51 Bitmapset *paramids; /* Non-local PARAM_EXEC paramids found */
52 } finalize_primnode_context;
55 static Node *build_subplan(PlannerInfo *root, Plan *plan, List *rtable,
56 SubLinkType subLinkType, Node *testexpr,
57 bool adjust_testexpr, bool unknownEqFalse);
58 static List *generate_subquery_params(PlannerInfo *root, List *tlist,
60 static List *generate_subquery_vars(PlannerInfo *root, List *tlist,
62 static Node *convert_testexpr(PlannerInfo *root,
65 static Node *convert_testexpr_mutator(Node *node,
66 convert_testexpr_context *context);
67 static bool subplan_is_hashable(Plan *plan);
68 static bool testexpr_is_hashable(Node *testexpr);
69 static bool hash_ok_operator(OpExpr *expr);
70 static bool simplify_EXISTS_query(Query *query);
71 static Query *convert_EXISTS_to_ANY(PlannerInfo *root, Query *subselect,
72 Node **testexpr, List **paramIds);
73 static Node *replace_correlation_vars_mutator(Node *node, PlannerInfo *root);
74 static Node *process_sublinks_mutator(Node *node,
75 process_sublinks_context *context);
76 static Bitmapset *finalize_plan(PlannerInfo *root,
78 Bitmapset *valid_params);
79 static bool finalize_primnode(Node *node, finalize_primnode_context *context);
83 * Generate a Param node to replace the given Var,
84 * which is expected to have varlevelsup > 0 (ie, it is not local).
87 replace_outer_var(PlannerInfo *root, Var *var)
91 PlannerParamItem *pitem;
95 Assert(var->varlevelsup > 0 && var->varlevelsup < root->query_level);
96 abslevel = root->query_level - var->varlevelsup;
99 * If there's already a paramlist entry for this same Var, just use it.
100 * NOTE: in sufficiently complex querytrees, it is possible for the same
101 * varno/abslevel to refer to different RTEs in different parts of the
102 * parsetree, so that different fields might end up sharing the same Param
103 * number. As long as we check the vartype/typmod as well, I believe that
104 * this sort of aliasing will cause no trouble. The correct field should
105 * get stored into the Param slot at execution in each part of the tree.
108 foreach(ppl, root->glob->paramlist)
110 pitem = (PlannerParamItem *) lfirst(ppl);
111 if (pitem->abslevel == abslevel && IsA(pitem->item, Var))
113 Var *pvar = (Var *) pitem->item;
115 if (pvar->varno == var->varno &&
116 pvar->varattno == var->varattno &&
117 pvar->vartype == var->vartype &&
118 pvar->vartypmod == var->vartypmod)
126 /* Nope, so make a new one */
127 var = (Var *) copyObject(var);
128 var->varlevelsup = 0;
130 pitem = makeNode(PlannerParamItem);
131 pitem->item = (Node *) var;
132 pitem->abslevel = abslevel;
134 root->glob->paramlist = lappend(root->glob->paramlist, pitem);
135 /* i is already the correct index for the new item */
138 retval = makeNode(Param);
139 retval->paramkind = PARAM_EXEC;
141 retval->paramtype = var->vartype;
142 retval->paramtypmod = var->vartypmod;
143 retval->location = -1;
149 * Generate a Param node to replace the given Aggref
150 * which is expected to have agglevelsup > 0 (ie, it is not local).
153 replace_outer_agg(PlannerInfo *root, Aggref *agg)
156 PlannerParamItem *pitem;
160 Assert(agg->agglevelsup > 0 && agg->agglevelsup < root->query_level);
161 abslevel = root->query_level - agg->agglevelsup;
164 * It does not seem worthwhile to try to match duplicate outer aggs. Just
165 * make a new slot every time.
167 agg = (Aggref *) copyObject(agg);
168 IncrementVarSublevelsUp((Node *) agg, -((int) agg->agglevelsup), 0);
169 Assert(agg->agglevelsup == 0);
171 pitem = makeNode(PlannerParamItem);
172 pitem->item = (Node *) agg;
173 pitem->abslevel = abslevel;
175 root->glob->paramlist = lappend(root->glob->paramlist, pitem);
176 i = list_length(root->glob->paramlist) - 1;
178 retval = makeNode(Param);
179 retval->paramkind = PARAM_EXEC;
181 retval->paramtype = agg->aggtype;
182 retval->paramtypmod = -1;
183 retval->location = -1;
189 * Generate a new Param node that will not conflict with any other.
191 * This is used to allocate PARAM_EXEC slots for subplan outputs.
194 generate_new_param(PlannerInfo *root, Oid paramtype, int32 paramtypmod)
197 PlannerParamItem *pitem;
199 retval = makeNode(Param);
200 retval->paramkind = PARAM_EXEC;
201 retval->paramid = list_length(root->glob->paramlist);
202 retval->paramtype = paramtype;
203 retval->paramtypmod = paramtypmod;
204 retval->location = -1;
206 pitem = makeNode(PlannerParamItem);
207 pitem->item = (Node *) retval;
208 pitem->abslevel = root->query_level;
210 root->glob->paramlist = lappend(root->glob->paramlist, pitem);
216 * Assign a (nonnegative) PARAM_EXEC ID for a recursive query's worktable.
219 SS_assign_worktable_param(PlannerInfo *root)
223 /* We generate a Param of datatype INTERNAL */
224 param = generate_new_param(root, INTERNALOID, -1);
225 /* ... but the caller only cares about its ID */
226 return param->paramid;
230 * Get the datatype of the first column of the plan's output.
232 * This is stored for ARRAY_SUBLINK execution and for exprType()/exprTypmod(),
233 * which have no way to get at the plan associated with a SubPlan node.
234 * We really only need the info for EXPR_SUBLINK and ARRAY_SUBLINK subplans,
235 * but for consistency we save it always.
238 get_first_col_type(Plan *plan, Oid *coltype, int32 *coltypmod)
240 /* In cases such as EXISTS, tlist might be empty; arbitrarily use VOID */
241 if (plan->targetlist)
243 TargetEntry *tent = (TargetEntry *) linitial(plan->targetlist);
245 Assert(IsA(tent, TargetEntry));
248 *coltype = exprType((Node *) tent->expr);
249 *coltypmod = exprTypmod((Node *) tent->expr);
258 * Convert a SubLink (as created by the parser) into a SubPlan.
260 * We are given the SubLink's contained query, type, and testexpr. We are
261 * also told if this expression appears at top level of a WHERE/HAVING qual.
263 * Note: we assume that the testexpr has been AND/OR flattened (actually,
264 * it's been through eval_const_expressions), but not converted to
265 * implicit-AND form; and any SubLinks in it should already have been
266 * converted to SubPlans. The subquery is as yet untouched, however.
268 * The result is whatever we need to substitute in place of the SubLink
269 * node in the executable expression. This will be either the SubPlan
270 * node (if we have to do the subplan as a subplan), or a Param node
271 * representing the result of an InitPlan, or a row comparison expression
272 * tree containing InitPlan Param nodes.
275 make_subplan(PlannerInfo *root, Query *orig_subquery, SubLinkType subLinkType,
276 Node *testexpr, bool isTopQual)
279 bool simple_exists = false;
280 double tuple_fraction;
282 PlannerInfo *subroot;
286 * Copy the source Query node. This is a quick and dirty kluge to resolve
287 * the fact that the parser can generate trees with multiple links to the
288 * same sub-Query node, but the planner wants to scribble on the Query.
289 * Try to clean this up when we do querytree redesign...
291 subquery = (Query *) copyObject(orig_subquery);
294 * If it's an EXISTS subplan, we might be able to simplify it.
296 if (subLinkType == EXISTS_SUBLINK)
297 simple_exists = simplify_EXISTS_query(subquery);
300 * For an EXISTS subplan, tell lower-level planner to expect that only the
301 * first tuple will be retrieved. For ALL and ANY subplans, we will be
302 * able to stop evaluating if the test condition fails or matches, so very
303 * often not all the tuples will be retrieved; for lack of a better idea,
304 * specify 50% retrieval. For EXPR and ROWCOMPARE subplans, use default
305 * behavior (we're only expecting one row out, anyway).
307 * NOTE: if you change these numbers, also change cost_subplan() in
310 * XXX If an ANY subplan is uncorrelated, build_subplan may decide to hash
311 * its output. In that case it would've been better to specify full
312 * retrieval. At present, however, we can only check hashability after
313 * we've made the subplan :-(. (Determining whether it'll fit in work_mem
314 * is the really hard part.) Therefore, we don't want to be too
315 * optimistic about the percentage of tuples retrieved, for fear of
316 * selecting a plan that's bad for the materialization case.
318 if (subLinkType == EXISTS_SUBLINK)
319 tuple_fraction = 1.0; /* just like a LIMIT 1 */
320 else if (subLinkType == ALL_SUBLINK ||
321 subLinkType == ANY_SUBLINK)
322 tuple_fraction = 0.5; /* 50% */
324 tuple_fraction = 0.0; /* default behavior */
327 * Generate the plan for the subquery.
329 plan = subquery_planner(root->glob, subquery,
331 false, tuple_fraction,
334 /* And convert to SubPlan or InitPlan format. */
335 result = build_subplan(root, plan, subroot->parse->rtable,
336 subLinkType, testexpr, true, isTopQual);
339 * If it's a correlated EXISTS with an unimportant targetlist, we might be
340 * able to transform it to the equivalent of an IN and then implement it
341 * by hashing. We don't have enough information yet to tell which way
342 * is likely to be better (it depends on the expected number of executions
343 * of the EXISTS qual, and we are much too early in planning the outer
344 * query to be able to guess that). So we generate both plans, if
345 * possible, and leave it to the executor to decide which to use.
347 if (simple_exists && IsA(result, SubPlan))
352 /* Make a second copy of the original subquery */
353 subquery = (Query *) copyObject(orig_subquery);
354 /* and re-simplify */
355 simple_exists = simplify_EXISTS_query(subquery);
356 Assert(simple_exists);
357 /* See if it can be converted to an ANY query */
358 subquery = convert_EXISTS_to_ANY(root, subquery,
359 &newtestexpr, ¶mIds);
362 /* Generate the plan for the ANY subquery; we'll need all rows */
363 plan = subquery_planner(root->glob, subquery,
368 /* Now we can check if it'll fit in work_mem */
369 if (subplan_is_hashable(plan))
372 AlternativeSubPlan *asplan;
374 /* OK, convert to SubPlan format. */
375 hashplan = (SubPlan *) build_subplan(root, plan,
376 subroot->parse->rtable,
377 ANY_SUBLINK, newtestexpr,
379 /* Check we got what we expected */
380 Assert(IsA(hashplan, SubPlan));
381 Assert(hashplan->parParam == NIL);
382 Assert(hashplan->useHashTable);
383 /* build_subplan won't have filled in paramIds */
384 hashplan->paramIds = paramIds;
386 /* Leave it to the executor to decide which plan to use */
387 asplan = makeNode(AlternativeSubPlan);
388 asplan->subplans = list_make2(result, hashplan);
389 result = (Node *) asplan;
398 * Build a SubPlan node given the raw inputs --- subroutine for make_subplan
400 * Returns either the SubPlan, or an expression using initplan output Params,
401 * as explained in the comments for make_subplan.
404 build_subplan(PlannerInfo *root, Plan *plan, List *rtable,
405 SubLinkType subLinkType, Node *testexpr,
406 bool adjust_testexpr, bool unknownEqFalse)
415 * Initialize the SubPlan node. Note plan_id isn't set till further down,
416 * likewise the cost fields.
418 splan = makeNode(SubPlan);
419 splan->subLinkType = subLinkType;
420 splan->testexpr = NULL;
421 splan->paramIds = NIL;
422 get_first_col_type(plan, &splan->firstColType, &splan->firstColTypmod);
423 splan->useHashTable = false;
424 splan->unknownEqFalse = unknownEqFalse;
425 splan->setParam = NIL;
426 splan->parParam = NIL;
430 * Make parParam and args lists of param IDs and expressions that current
431 * query level will pass to this child plan.
433 tmpset = bms_copy(plan->extParam);
434 while ((paramid = bms_first_member(tmpset)) >= 0)
436 PlannerParamItem *pitem = list_nth(root->glob->paramlist, paramid);
438 if (pitem->abslevel == root->query_level)
440 splan->parParam = lappend_int(splan->parParam, paramid);
442 * The Var or Aggref has already been adjusted to have the correct
443 * varlevelsup or agglevelsup. We probably don't even need to
444 * copy it again, but be safe.
446 splan->args = lappend(splan->args, copyObject(pitem->item));
452 * Un-correlated or undirect correlated plans of EXISTS, EXPR, ARRAY, or
453 * ROWCOMPARE types can be used as initPlans. For EXISTS, EXPR, or ARRAY,
454 * we just produce a Param referring to the result of evaluating the
455 * initPlan. For ROWCOMPARE, we must modify the testexpr tree to contain
456 * PARAM_EXEC Params instead of the PARAM_SUBLINK Params emitted by the
459 if (splan->parParam == NIL && subLinkType == EXISTS_SUBLINK)
463 Assert(testexpr == NULL);
464 prm = generate_new_param(root, BOOLOID, -1);
465 splan->setParam = list_make1_int(prm->paramid);
467 result = (Node *) prm;
469 else if (splan->parParam == NIL && subLinkType == EXPR_SUBLINK)
471 TargetEntry *te = linitial(plan->targetlist);
474 Assert(!te->resjunk);
475 Assert(testexpr == NULL);
476 prm = generate_new_param(root,
477 exprType((Node *) te->expr),
478 exprTypmod((Node *) te->expr));
479 splan->setParam = list_make1_int(prm->paramid);
481 result = (Node *) prm;
483 else if (splan->parParam == NIL && subLinkType == ARRAY_SUBLINK)
485 TargetEntry *te = linitial(plan->targetlist);
489 Assert(!te->resjunk);
490 Assert(testexpr == NULL);
491 arraytype = get_array_type(exprType((Node *) te->expr));
492 if (!OidIsValid(arraytype))
493 elog(ERROR, "could not find array type for datatype %s",
494 format_type_be(exprType((Node *) te->expr)));
495 prm = generate_new_param(root,
497 exprTypmod((Node *) te->expr));
498 splan->setParam = list_make1_int(prm->paramid);
500 result = (Node *) prm;
502 else if (splan->parParam == NIL && subLinkType == ROWCOMPARE_SUBLINK)
504 /* Adjust the Params */
507 Assert(testexpr != NULL);
508 params = generate_subquery_params(root,
511 result = convert_testexpr(root,
514 splan->setParam = list_copy(splan->paramIds);
518 * The executable expression is returned to become part of the outer
519 * plan's expression tree; it is not kept in the initplan node.
525 * Adjust the Params in the testexpr, unless caller said it's not
528 if (testexpr && adjust_testexpr)
532 params = generate_subquery_params(root,
535 splan->testexpr = convert_testexpr(root,
540 splan->testexpr = testexpr;
543 * We can't convert subplans of ALL_SUBLINK or ANY_SUBLINK types to
544 * initPlans, even when they are uncorrelated or undirect correlated,
545 * because we need to scan the output of the subplan for each outer
546 * tuple. But if it's a not-direct-correlated IN (= ANY) test, we
547 * might be able to use a hashtable to avoid comparing all the tuples.
549 if (subLinkType == ANY_SUBLINK &&
550 splan->parParam == NIL &&
551 subplan_is_hashable(plan) &&
552 testexpr_is_hashable(splan->testexpr))
553 splan->useHashTable = true;
556 * Otherwise, we have the option to tack a MATERIAL node onto the top
557 * of the subplan, to reduce the cost of reading it repeatedly. This
558 * is pointless for a direct-correlated subplan, since we'd have to
559 * recompute its results each time anyway. For uncorrelated/undirect
560 * correlated subplans, we add MATERIAL unless the subplan's top plan
561 * node would materialize its output anyway.
563 else if (splan->parParam == NIL)
567 switch (nodeTag(plan))
572 case T_WorkTableScan:
574 use_material = false;
581 plan = materialize_finished_plan(plan);
584 result = (Node *) splan;
589 * Add the subplan and its rtable to the global lists.
591 root->glob->subplans = lappend(root->glob->subplans, plan);
592 root->glob->subrtables = lappend(root->glob->subrtables, rtable);
593 splan->plan_id = list_length(root->glob->subplans);
596 root->init_plans = lappend(root->init_plans, splan);
599 * A parameterless subplan (not initplan) should be prepared to handle
600 * REWIND efficiently. If it has direct parameters then there's no point
601 * since it'll be reset on each scan anyway; and if it's an initplan then
602 * there's no point since it won't get re-run without parameter changes
603 * anyway. The input of a hashed subplan doesn't need REWIND either.
605 if (splan->parParam == NIL && !isInitPlan && !splan->useHashTable)
606 root->glob->rewindPlanIDs = bms_add_member(root->glob->rewindPlanIDs,
609 /* Lastly, fill in the cost estimates for use later */
610 cost_subplan(root, splan, plan);
616 * generate_subquery_params: build a list of Params representing the output
617 * columns of a sublink's sub-select, given the sub-select's targetlist.
619 * We also return an integer list of the paramids of the Params.
622 generate_subquery_params(PlannerInfo *root, List *tlist, List **paramIds)
631 TargetEntry *tent = (TargetEntry *) lfirst(lc);
637 param = generate_new_param(root,
638 exprType((Node *) tent->expr),
639 exprTypmod((Node *) tent->expr));
640 result = lappend(result, param);
641 ids = lappend_int(ids, param->paramid);
649 * generate_subquery_vars: build a list of Vars representing the output
650 * columns of a sublink's sub-select, given the sub-select's targetlist.
651 * The Vars have the specified varno (RTE index).
654 generate_subquery_vars(PlannerInfo *root, List *tlist, Index varno)
662 TargetEntry *tent = (TargetEntry *) lfirst(lc);
670 exprType((Node *) tent->expr),
671 exprTypmod((Node *) tent->expr),
673 result = lappend(result, var);
680 * convert_testexpr: convert the testexpr given by the parser into
681 * actually executable form. This entails replacing PARAM_SUBLINK Params
682 * with Params or Vars representing the results of the sub-select. The
683 * nodes to be substituted are passed in as the List result from
684 * generate_subquery_params or generate_subquery_vars.
686 * The given testexpr has already been recursively processed by
687 * process_sublinks_mutator. Hence it can no longer contain any
688 * PARAM_SUBLINK Params for lower SubLink nodes; we can safely assume that
689 * any we find are for our own level of SubLink.
692 convert_testexpr(PlannerInfo *root,
696 convert_testexpr_context context;
699 context.subst_nodes = subst_nodes;
700 return convert_testexpr_mutator(testexpr, &context);
704 convert_testexpr_mutator(Node *node,
705 convert_testexpr_context *context)
709 if (IsA(node, Param))
711 Param *param = (Param *) node;
713 if (param->paramkind == PARAM_SUBLINK)
715 if (param->paramid <= 0 ||
716 param->paramid > list_length(context->subst_nodes))
717 elog(ERROR, "unexpected PARAM_SUBLINK ID: %d", param->paramid);
720 * We copy the list item to avoid having doubly-linked
721 * substructure in the modified parse tree. This is probably
722 * unnecessary when it's a Param, but be safe.
724 return (Node *) copyObject(list_nth(context->subst_nodes,
725 param->paramid - 1));
728 return expression_tree_mutator(node,
729 convert_testexpr_mutator,
734 * subplan_is_hashable: can we implement an ANY subplan by hashing?
737 subplan_is_hashable(Plan *plan)
739 double subquery_size;
742 * The estimated size of the subquery result must fit in work_mem. (Note:
743 * we use sizeof(HeapTupleHeaderData) here even though the tuples will
744 * actually be stored as MinimalTuples; this provides some fudge factor
745 * for hashtable overhead.)
747 subquery_size = plan->plan_rows *
748 (MAXALIGN(plan->plan_width) + MAXALIGN(sizeof(HeapTupleHeaderData)));
749 if (subquery_size > work_mem * 1024L)
756 * testexpr_is_hashable: is an ANY SubLink's test expression hashable?
759 testexpr_is_hashable(Node *testexpr)
762 * The testexpr must be a single OpExpr, or an AND-clause containing
765 * The combining operators must be hashable and strict. The need for
766 * hashability is obvious, since we want to use hashing. Without
767 * strictness, behavior in the presence of nulls is too unpredictable. We
768 * actually must assume even more than plain strictness: they can't yield
769 * NULL for non-null inputs, either (see nodeSubplan.c). However, hash
770 * indexes and hash joins assume that too.
772 if (testexpr && IsA(testexpr, OpExpr))
774 if (hash_ok_operator((OpExpr *) testexpr))
777 else if (and_clause(testexpr))
781 foreach(l, ((BoolExpr *) testexpr)->args)
783 Node *andarg = (Node *) lfirst(l);
785 if (!IsA(andarg, OpExpr))
787 if (!hash_ok_operator((OpExpr *) andarg))
797 hash_ok_operator(OpExpr *expr)
799 Oid opid = expr->opno;
801 Form_pg_operator optup;
803 /* quick out if not a binary operator */
804 if (list_length(expr->args) != 2)
806 /* else must look up the operator properties */
807 tup = SearchSysCache(OPEROID,
808 ObjectIdGetDatum(opid),
810 if (!HeapTupleIsValid(tup))
811 elog(ERROR, "cache lookup failed for operator %u", opid);
812 optup = (Form_pg_operator) GETSTRUCT(tup);
813 if (!optup->oprcanhash || !func_strict(optup->oprcode))
815 ReleaseSysCache(tup);
818 ReleaseSysCache(tup);
824 * SS_process_ctes: process a query's WITH list
826 * We plan each interesting WITH item and convert it to an initplan.
827 * A side effect is to fill in root->cte_plan_ids with a list that
828 * parallels root->parse->cteList and provides the subplan ID for
829 * each CTE's initplan.
832 SS_process_ctes(PlannerInfo *root)
836 Assert(root->cte_plan_ids == NIL);
838 foreach(lc, root->parse->cteList)
840 CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
843 PlannerInfo *subroot;
850 * Ignore CTEs that are not actually referenced anywhere.
852 if (cte->cterefcount == 0)
854 /* Make a dummy entry in cte_plan_ids */
855 root->cte_plan_ids = lappend_int(root->cte_plan_ids, -1);
860 * Copy the source Query node. Probably not necessary, but let's
861 * keep this similar to make_subplan.
863 subquery = (Query *) copyObject(cte->ctequery);
866 * Generate the plan for the CTE query. Always plan for full
867 * retrieval --- we don't have enough info to predict otherwise.
869 plan = subquery_planner(root->glob, subquery,
871 cte->cterecursive, 0.0,
875 * Make a SubPlan node for it. This is just enough unlike
876 * build_subplan that we can't share code.
878 * Note plan_id isn't set till further down, likewise the cost fields.
880 splan = makeNode(SubPlan);
881 splan->subLinkType = CTE_SUBLINK;
882 splan->testexpr = NULL;
883 splan->paramIds = NIL;
884 get_first_col_type(plan, &splan->firstColType, &splan->firstColTypmod);
885 splan->useHashTable = false;
886 splan->unknownEqFalse = false;
887 splan->setParam = NIL;
888 splan->parParam = NIL;
892 * Make parParam and args lists of param IDs and expressions that
893 * current query level will pass to this child plan. Even though
894 * this is an initplan, there could be side-references to earlier
895 * initplan's outputs, specifically their CTE output parameters.
897 tmpset = bms_copy(plan->extParam);
898 while ((paramid = bms_first_member(tmpset)) >= 0)
900 PlannerParamItem *pitem = list_nth(root->glob->paramlist, paramid);
902 if (pitem->abslevel == root->query_level)
904 prm = (Param *) pitem->item;
905 if (!IsA(prm, Param) ||
906 prm->paramtype != INTERNALOID)
907 elog(ERROR, "bogus local parameter passed to WITH query");
909 splan->parParam = lappend_int(splan->parParam, paramid);
910 splan->args = lappend(splan->args, copyObject(prm));
916 * Assign a param to represent the query output. We only really
917 * care about reserving a parameter ID number.
919 prm = generate_new_param(root, INTERNALOID, -1);
920 splan->setParam = list_make1_int(prm->paramid);
923 * Add the subplan and its rtable to the global lists.
925 root->glob->subplans = lappend(root->glob->subplans, plan);
926 root->glob->subrtables = lappend(root->glob->subrtables,
927 subroot->parse->rtable);
928 splan->plan_id = list_length(root->glob->subplans);
930 root->init_plans = lappend(root->init_plans, splan);
932 root->cte_plan_ids = lappend_int(root->cte_plan_ids, splan->plan_id);
934 /* Lastly, fill in the cost estimates for use later */
935 cost_subplan(root, splan, plan);
940 * convert_ANY_sublink_to_join: try to convert an ANY SubLink to a join
942 * The caller has found an ANY SubLink at the top level of one of the query's
943 * qual clauses, but has not checked the properties of the SubLink further.
944 * Decide whether it is appropriate to process this SubLink in join style.
945 * If so, form a JoinExpr and return it. Return NULL if the SubLink cannot
946 * be converted to a join.
948 * The only non-obvious input parameter is available_rels: this is the set
949 * of query rels that can safely be referenced in the sublink expression.
950 * (We must restrict this to avoid changing the semantics when a sublink
951 * is present in an outer join's ON qual.) The conversion must fail if
952 * the converted qual would reference any but these parent-query relids.
954 * On success, the returned JoinExpr has larg = NULL and rarg = the jointree
955 * item representing the pulled-up subquery. The caller must set larg to
956 * represent the relation(s) on the lefthand side of the new join, and insert
957 * the JoinExpr into the upper query's jointree at an appropriate place
958 * (typically, where the lefthand relation(s) had been). Note that the
959 * passed-in SubLink must also be removed from its original position in the
960 * query quals, since the quals of the returned JoinExpr replace it.
961 * (Notionally, we replace the SubLink with a constant TRUE, then elide the
962 * redundant constant from the qual.)
964 * Side effects of a successful conversion include adding the SubLink's
965 * subselect to the query's rangetable, so that it can be referenced in
966 * the JoinExpr's rarg.
969 convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
970 Relids available_rels)
973 Query *parse = root->parse;
974 Query *subselect = (Query *) sublink->subselect;
982 Assert(sublink->subLinkType == ANY_SUBLINK);
985 * The sub-select must not refer to any Vars of the parent query. (Vars of
986 * higher levels should be okay, though.)
988 if (contain_vars_of_level((Node *) subselect, 1))
992 * The test expression must contain some Vars of the parent query,
993 * else it's not gonna be a join. (Note that it won't have Vars
994 * referring to the subquery, rather Params.)
996 upper_varnos = pull_varnos(sublink->testexpr);
997 if (bms_is_empty(upper_varnos))
1001 * However, it can't refer to anything outside available_rels.
1003 if (!bms_is_subset(upper_varnos, available_rels))
1007 * The combining operators and left-hand expressions mustn't be volatile.
1009 if (contain_volatile_functions(sublink->testexpr))
1013 * Okay, pull up the sub-select into upper range table.
1015 * We rely here on the assumption that the outer query has no references
1016 * to the inner (necessarily true, other than the Vars that we build
1017 * below). Therefore this is a lot easier than what pull_up_subqueries has
1020 rte = addRangeTableEntryForSubquery(NULL,
1022 makeAlias("ANY_subquery", NIL),
1024 parse->rtable = lappend(parse->rtable, rte);
1025 rtindex = list_length(parse->rtable);
1028 * Form a RangeTblRef for the pulled-up sub-select.
1030 rtr = makeNode(RangeTblRef);
1031 rtr->rtindex = rtindex;
1034 * Build a list of Vars representing the subselect outputs.
1036 subquery_vars = generate_subquery_vars(root,
1037 subselect->targetList,
1041 * Build the new join's qual expression, replacing Params with these Vars.
1043 quals = convert_testexpr(root, sublink->testexpr, subquery_vars);
1046 * And finally, build the JoinExpr node.
1048 result = makeNode(JoinExpr);
1049 result->jointype = JOIN_SEMI;
1050 result->isNatural = false;
1051 result->larg = NULL; /* caller must fill this in */
1052 result->rarg = (Node *) rtr;
1053 result->using = NIL;
1054 result->quals = quals;
1055 result->alias = NULL;
1056 result->rtindex = 0; /* we don't need an RTE for it */
1062 * convert_EXISTS_sublink_to_join: try to convert an EXISTS SubLink to a join
1064 * The API of this function is identical to convert_ANY_sublink_to_join's,
1065 * except that we also support the case where the caller has found NOT EXISTS,
1066 * so we need an additional input parameter "under_not".
1069 convert_EXISTS_sublink_to_join(PlannerInfo *root, SubLink *sublink,
1070 bool under_not, Relids available_rels)
1073 Query *parse = root->parse;
1074 Query *subselect = (Query *) sublink->subselect;
1078 Relids clause_varnos;
1079 Relids upper_varnos;
1081 Assert(sublink->subLinkType == EXISTS_SUBLINK);
1084 * Copy the subquery so we can modify it safely (see comments in
1087 subselect = (Query *) copyObject(subselect);
1090 * See if the subquery can be simplified based on the knowledge that
1091 * it's being used in EXISTS(). If we aren't able to get rid of its
1092 * targetlist, we have to fail, because the pullup operation leaves
1093 * us with noplace to evaluate the targetlist.
1095 if (!simplify_EXISTS_query(subselect))
1099 * The subquery must have a nonempty jointree, else we won't have a join.
1101 if (subselect->jointree->fromlist == NIL)
1105 * Separate out the WHERE clause. (We could theoretically also remove
1106 * top-level plain JOIN/ON clauses, but it's probably not worth the
1109 whereClause = subselect->jointree->quals;
1110 subselect->jointree->quals = NULL;
1113 * The rest of the sub-select must not refer to any Vars of the parent
1114 * query. (Vars of higher levels should be okay, though.)
1116 if (contain_vars_of_level((Node *) subselect, 1))
1120 * On the other hand, the WHERE clause must contain some Vars of the
1121 * parent query, else it's not gonna be a join.
1123 if (!contain_vars_of_level(whereClause, 1))
1127 * We don't risk optimizing if the WHERE clause is volatile, either.
1129 if (contain_volatile_functions(whereClause))
1133 * Prepare to pull up the sub-select into top range table.
1135 * We rely here on the assumption that the outer query has no references
1136 * to the inner (necessarily true). Therefore this is a lot easier than
1137 * what pull_up_subqueries has to go through.
1139 * In fact, it's even easier than what convert_ANY_sublink_to_join has
1140 * to do. The machinations of simplify_EXISTS_query ensured that there
1141 * is nothing interesting in the subquery except an rtable and jointree,
1142 * and even the jointree FromExpr no longer has quals. So we can just
1143 * append the rtable to our own and use the FromExpr in our jointree.
1144 * But first, adjust all level-zero varnos in the subquery to account
1145 * for the rtable merger.
1147 rtoffset = list_length(parse->rtable);
1148 OffsetVarNodes((Node *) subselect, rtoffset, 0);
1149 OffsetVarNodes(whereClause, rtoffset, 0);
1152 * Upper-level vars in subquery will now be one level closer to their
1153 * parent than before; in particular, anything that had been level 1
1154 * becomes level zero.
1156 IncrementVarSublevelsUp((Node *) subselect, -1, 1);
1157 IncrementVarSublevelsUp(whereClause, -1, 1);
1160 * Now that the WHERE clause is adjusted to match the parent query
1161 * environment, we can easily identify all the level-zero rels it uses.
1162 * The ones <= rtoffset belong to the upper query; the ones > rtoffset
1165 clause_varnos = pull_varnos(whereClause);
1166 upper_varnos = NULL;
1167 while ((varno = bms_first_member(clause_varnos)) >= 0)
1169 if (varno <= rtoffset)
1170 upper_varnos = bms_add_member(upper_varnos, varno);
1172 bms_free(clause_varnos);
1173 Assert(!bms_is_empty(upper_varnos));
1176 * Now that we've got the set of upper-level varnos, we can make the
1177 * last check: only available_rels can be referenced.
1179 if (!bms_is_subset(upper_varnos, available_rels))
1182 /* Now we can attach the modified subquery rtable to the parent */
1183 parse->rtable = list_concat(parse->rtable, subselect->rtable);
1186 * And finally, build the JoinExpr node.
1188 result = makeNode(JoinExpr);
1189 result->jointype = under_not ? JOIN_ANTI : JOIN_SEMI;
1190 result->isNatural = false;
1191 result->larg = NULL; /* caller must fill this in */
1192 /* flatten out the FromExpr node if it's useless */
1193 if (list_length(subselect->jointree->fromlist) == 1)
1194 result->rarg = (Node *) linitial(subselect->jointree->fromlist);
1196 result->rarg = (Node *) subselect->jointree;
1197 result->using = NIL;
1198 result->quals = whereClause;
1199 result->alias = NULL;
1200 result->rtindex = 0; /* we don't need an RTE for it */
1206 * simplify_EXISTS_query: remove any useless stuff in an EXISTS's subquery
1208 * The only thing that matters about an EXISTS query is whether it returns
1209 * zero or more than zero rows. Therefore, we can remove certain SQL features
1210 * that won't affect that. The only part that is really likely to matter in
1211 * typical usage is simplifying the targetlist: it's a common habit to write
1212 * "SELECT * FROM" even though there is no need to evaluate any columns.
1214 * Note: by suppressing the targetlist we could cause an observable behavioral
1215 * change, namely that any errors that might occur in evaluating the tlist
1216 * won't occur, nor will other side-effects of volatile functions. This seems
1217 * unlikely to bother anyone in practice.
1219 * Returns TRUE if was able to discard the targetlist, else FALSE.
1222 simplify_EXISTS_query(Query *query)
1225 * We don't try to simplify at all if the query uses set operations,
1226 * aggregates, HAVING, LIMIT/OFFSET, or FOR UPDATE/SHARE; none of these
1227 * seem likely in normal usage and their possible effects are complex.
1229 if (query->commandType != CMD_SELECT ||
1230 query->intoClause ||
1231 query->setOperations ||
1233 query->hasWindowFuncs ||
1234 query->havingQual ||
1235 query->limitOffset ||
1236 query->limitCount ||
1241 * Mustn't throw away the targetlist if it contains set-returning
1242 * functions; those could affect whether zero rows are returned!
1244 if (expression_returns_set((Node *) query->targetList))
1248 * Otherwise, we can throw away the targetlist, as well as any GROUP,
1249 * WINDOW, DISTINCT, and ORDER BY clauses; none of those clauses will
1250 * change a nonzero-rows result to zero rows or vice versa. (Furthermore,
1251 * since our parsetree representation of these clauses depends on the
1252 * targetlist, we'd better throw them away if we drop the targetlist.)
1254 query->targetList = NIL;
1255 query->groupClause = NIL;
1256 query->windowClause = NIL;
1257 query->distinctClause = NIL;
1258 query->sortClause = NIL;
1259 query->hasDistinctOn = false;
1265 * convert_EXISTS_to_ANY: try to convert EXISTS to a hashable ANY sublink
1267 * The subselect is expected to be a fresh copy that we can munge up,
1268 * and to have been successfully passed through simplify_EXISTS_query.
1270 * On success, the modified subselect is returned, and we store a suitable
1271 * upper-level test expression at *testexpr, plus a list of the subselect's
1272 * output Params at *paramIds. (The test expression is already Param-ified
1273 * and hence need not go through convert_testexpr, which is why we have to
1274 * deal with the Param IDs specially.)
1276 * On failure, returns NULL.
1279 convert_EXISTS_to_ANY(PlannerInfo *root, Query *subselect,
1280 Node **testexpr, List **paramIds)
1296 * Query must not require a targetlist, since we have to insert a new one.
1297 * Caller should have dealt with the case already.
1299 Assert(subselect->targetList == NIL);
1302 * Separate out the WHERE clause. (We could theoretically also remove
1303 * top-level plain JOIN/ON clauses, but it's probably not worth the
1306 whereClause = subselect->jointree->quals;
1307 subselect->jointree->quals = NULL;
1310 * The rest of the sub-select must not refer to any Vars of the parent
1311 * query. (Vars of higher levels should be okay, though.)
1313 * Note: we need not check for Aggrefs separately because we know the
1314 * sub-select is as yet unoptimized; any uplevel Aggref must therefore
1315 * contain an uplevel Var reference. This is not the case below ...
1317 if (contain_vars_of_level((Node *) subselect, 1))
1321 * We don't risk optimizing if the WHERE clause is volatile, either.
1323 if (contain_volatile_functions(whereClause))
1327 * Clean up the WHERE clause by doing const-simplification etc on it.
1328 * Aside from simplifying the processing we're about to do, this is
1329 * important for being able to pull chunks of the WHERE clause up into
1330 * the parent query. Since we are invoked partway through the parent's
1331 * preprocess_expression() work, earlier steps of preprocess_expression()
1332 * wouldn't get applied to the pulled-up stuff unless we do them here.
1333 * For the parts of the WHERE clause that get put back into the child
1334 * query, this work is partially duplicative, but it shouldn't hurt.
1336 * Note: we do not run flatten_join_alias_vars. This is OK because
1337 * any parent aliases were flattened already, and we're not going to
1338 * pull any child Vars (of any description) into the parent.
1340 * Note: passing the parent's root to eval_const_expressions is technically
1341 * wrong, but we can get away with it since only the boundParams (if any)
1342 * are used, and those would be the same in a subroot.
1344 whereClause = eval_const_expressions(root, whereClause);
1345 whereClause = (Node *) canonicalize_qual((Expr *) whereClause);
1346 whereClause = (Node *) make_ands_implicit((Expr *) whereClause);
1349 * We now have a flattened implicit-AND list of clauses, which we
1350 * try to break apart into "outervar = innervar" hash clauses.
1351 * Anything that can't be broken apart just goes back into the
1352 * newWhere list. Note that we aren't trying hard yet to ensure
1353 * that we have only outer or only inner on each side; we'll check
1354 * that if we get to the end.
1356 leftargs = rightargs = opids = newWhere = NIL;
1357 foreach(lc, (List *) whereClause)
1359 OpExpr *expr = (OpExpr *) lfirst(lc);
1361 if (IsA(expr, OpExpr) &&
1362 hash_ok_operator(expr))
1364 Node *leftarg = (Node *) linitial(expr->args);
1365 Node *rightarg = (Node *) lsecond(expr->args);
1367 if (contain_vars_of_level(leftarg, 1))
1369 leftargs = lappend(leftargs, leftarg);
1370 rightargs = lappend(rightargs, rightarg);
1371 opids = lappend_oid(opids, expr->opno);
1374 if (contain_vars_of_level(rightarg, 1))
1377 * We must commute the clause to put the outer var on the
1378 * left, because the hashing code in nodeSubplan.c expects
1379 * that. This probably shouldn't ever fail, since hashable
1380 * operators ought to have commutators, but be paranoid.
1382 expr->opno = get_commutator(expr->opno);
1383 if (OidIsValid(expr->opno) && hash_ok_operator(expr))
1385 leftargs = lappend(leftargs, rightarg);
1386 rightargs = lappend(rightargs, leftarg);
1387 opids = lappend_oid(opids, expr->opno);
1390 /* If no commutator, no chance to optimize the WHERE clause */
1394 /* Couldn't handle it as a hash clause */
1395 newWhere = lappend(newWhere, expr);
1399 * If we didn't find anything we could convert, fail.
1401 if (leftargs == NIL)
1405 * There mustn't be any parent Vars or Aggs in the stuff that we intend to
1406 * put back into the child query. Note: you might think we don't need to
1407 * check for Aggs separately, because an uplevel Agg must contain an
1408 * uplevel Var in its argument. But it is possible that the uplevel Var
1409 * got optimized away by eval_const_expressions. Consider
1411 * SUM(CASE WHEN false THEN uplevelvar ELSE 0 END)
1413 if (contain_vars_of_level((Node *) newWhere, 1) ||
1414 contain_vars_of_level((Node *) rightargs, 1))
1416 if (root->parse->hasAggs &&
1417 (contain_aggs_of_level((Node *) newWhere, 1) ||
1418 contain_aggs_of_level((Node *) rightargs, 1)))
1422 * And there can't be any child Vars in the stuff we intend to pull up.
1423 * (Note: we'd need to check for child Aggs too, except we know the
1424 * child has no aggs at all because of simplify_EXISTS_query's check.
1425 * The same goes for window functions.)
1427 if (contain_vars_of_level((Node *) leftargs, 0))
1431 * Also reject sublinks in the stuff we intend to pull up. (It might be
1432 * possible to support this, but doesn't seem worth the complication.)
1434 if (contain_subplans((Node *) leftargs))
1438 * Okay, adjust the sublevelsup in the stuff we're pulling up.
1440 IncrementVarSublevelsUp((Node *) leftargs, -1, 1);
1443 * Put back any child-level-only WHERE clauses.
1446 subselect->jointree->quals = (Node *) make_ands_explicit(newWhere);
1449 * Build a new targetlist for the child that emits the expressions
1450 * we need. Concurrently, build a testexpr for the parent using
1451 * Params to reference the child outputs. (Since we generate Params
1452 * directly here, there will be no need to convert the testexpr in
1455 tlist = testlist = paramids = NIL;
1457 /* there's no "for3" so we have to chase one of the lists manually */
1458 oc = list_head(opids);
1459 forboth(lc, leftargs, rc, rightargs)
1461 Node *leftarg = (Node *) lfirst(lc);
1462 Node *rightarg = (Node *) lfirst(rc);
1463 Oid opid = lfirst_oid(oc);
1467 param = generate_new_param(root,
1469 exprTypmod(rightarg));
1470 tlist = lappend(tlist,
1471 makeTargetEntry((Expr *) rightarg,
1475 testlist = lappend(testlist,
1476 make_opclause(opid, BOOLOID, false,
1477 (Expr *) leftarg, (Expr *) param));
1478 paramids = lappend_int(paramids, param->paramid);
1481 /* Put everything where it should go, and we're done */
1482 subselect->targetList = tlist;
1483 *testexpr = (Node *) make_ands_explicit(testlist);
1484 *paramIds = paramids;
1491 * Replace correlation vars (uplevel vars) with Params.
1493 * Uplevel aggregates are replaced, too.
1495 * Note: it is critical that this runs immediately after SS_process_sublinks.
1496 * Since we do not recurse into the arguments of uplevel aggregates, they will
1497 * get copied to the appropriate subplan args list in the parent query with
1498 * uplevel vars not replaced by Params, but only adjusted in level (see
1499 * replace_outer_agg). That's exactly what we want for the vars of the parent
1500 * level --- but if an aggregate's argument contains any further-up variables,
1501 * they have to be replaced with Params in their turn. That will happen when
1502 * the parent level runs SS_replace_correlation_vars. Therefore it must do
1503 * so after expanding its sublinks to subplans. And we don't want any steps
1504 * in between, else those steps would never get applied to the aggregate
1505 * argument expressions, either in the parent or the child level.
1508 SS_replace_correlation_vars(PlannerInfo *root, Node *expr)
1510 /* No setup needed for tree walk, so away we go */
1511 return replace_correlation_vars_mutator(expr, root);
1515 replace_correlation_vars_mutator(Node *node, PlannerInfo *root)
1521 if (((Var *) node)->varlevelsup > 0)
1522 return (Node *) replace_outer_var(root, (Var *) node);
1524 if (IsA(node, Aggref))
1526 if (((Aggref *) node)->agglevelsup > 0)
1527 return (Node *) replace_outer_agg(root, (Aggref *) node);
1529 return expression_tree_mutator(node,
1530 replace_correlation_vars_mutator,
1535 * Expand SubLinks to SubPlans in the given expression.
1537 * The isQual argument tells whether or not this expression is a WHERE/HAVING
1538 * qualifier expression. If it is, any sublinks appearing at top level need
1539 * not distinguish FALSE from UNKNOWN return values.
1542 SS_process_sublinks(PlannerInfo *root, Node *expr, bool isQual)
1544 process_sublinks_context context;
1546 context.root = root;
1547 context.isTopQual = isQual;
1548 return process_sublinks_mutator(expr, &context);
1552 process_sublinks_mutator(Node *node, process_sublinks_context *context)
1554 process_sublinks_context locContext;
1556 locContext.root = context->root;
1560 if (IsA(node, SubLink))
1562 SubLink *sublink = (SubLink *) node;
1566 * First, recursively process the lefthand-side expressions, if any.
1567 * They're not top-level anymore.
1569 locContext.isTopQual = false;
1570 testexpr = process_sublinks_mutator(sublink->testexpr, &locContext);
1573 * Now build the SubPlan node and make the expr to return.
1575 return make_subplan(context->root,
1576 (Query *) sublink->subselect,
1577 sublink->subLinkType,
1579 context->isTopQual);
1583 * We should never see a SubPlan expression in the input (since this is
1584 * the very routine that creates 'em to begin with). We shouldn't find
1585 * ourselves invoked directly on a Query, either.
1587 Assert(!IsA(node, SubPlan));
1588 Assert(!IsA(node, AlternativeSubPlan));
1589 Assert(!IsA(node, Query));
1592 * Because make_subplan() could return an AND or OR clause, we have to
1593 * take steps to preserve AND/OR flatness of a qual. We assume the input
1594 * has been AND/OR flattened and so we need no recursion here.
1596 * (Due to the coding here, we will not get called on the List subnodes of
1597 * an AND; and the input is *not* yet in implicit-AND format. So no check
1598 * is needed for a bare List.)
1600 * Anywhere within the top-level AND/OR clause structure, we can tell
1601 * make_subplan() that NULL and FALSE are interchangeable. So isTopQual
1602 * propagates down in both cases. (Note that this is unlike the meaning
1603 * of "top level qual" used in most other places in Postgres.)
1605 if (and_clause(node))
1607 List *newargs = NIL;
1610 /* Still at qual top-level */
1611 locContext.isTopQual = context->isTopQual;
1613 foreach(l, ((BoolExpr *) node)->args)
1617 newarg = process_sublinks_mutator(lfirst(l), &locContext);
1618 if (and_clause(newarg))
1619 newargs = list_concat(newargs, ((BoolExpr *) newarg)->args);
1621 newargs = lappend(newargs, newarg);
1623 return (Node *) make_andclause(newargs);
1626 if (or_clause(node))
1628 List *newargs = NIL;
1631 /* Still at qual top-level */
1632 locContext.isTopQual = context->isTopQual;
1634 foreach(l, ((BoolExpr *) node)->args)
1638 newarg = process_sublinks_mutator(lfirst(l), &locContext);
1639 if (or_clause(newarg))
1640 newargs = list_concat(newargs, ((BoolExpr *) newarg)->args);
1642 newargs = lappend(newargs, newarg);
1644 return (Node *) make_orclause(newargs);
1648 * If we recurse down through anything other than an AND or OR node,
1649 * we are definitely not at top qual level anymore.
1651 locContext.isTopQual = false;
1653 return expression_tree_mutator(node,
1654 process_sublinks_mutator,
1655 (void *) &locContext);
1659 * SS_finalize_plan - do final sublink processing for a completed Plan.
1661 * This recursively computes the extParam and allParam sets for every Plan
1662 * node in the given plan tree. It also optionally attaches any previously
1663 * generated InitPlans to the top plan node. (Any InitPlans should already
1664 * have been put through SS_finalize_plan.)
1667 SS_finalize_plan(PlannerInfo *root, Plan *plan, bool attach_initplans)
1669 Bitmapset *valid_params,
1677 * Examine any initPlans to determine the set of external params they
1678 * reference, the set of output params they supply, and their total cost.
1679 * We'll use at least some of this info below. (Note we are assuming that
1680 * finalize_plan doesn't touch the initPlans.)
1682 * In the case where attach_initplans is false, we are assuming that the
1683 * existing initPlans are siblings that might supply params needed by the
1686 initExtParam = initSetParam = NULL;
1688 foreach(l, root->init_plans)
1690 SubPlan *initsubplan = (SubPlan *) lfirst(l);
1691 Plan *initplan = planner_subplan_get_plan(root, initsubplan);
1694 initExtParam = bms_add_members(initExtParam, initplan->extParam);
1695 foreach(l2, initsubplan->setParam)
1697 initSetParam = bms_add_member(initSetParam, lfirst_int(l2));
1699 initplan_cost += initsubplan->startup_cost + initsubplan->per_call_cost;
1703 * Now determine the set of params that are validly referenceable in this
1704 * query level; to wit, those available from outer query levels plus the
1705 * output parameters of any initPlans. (We do not include output
1706 * parameters of regular subplans. Those should only appear within the
1707 * testexpr of SubPlan nodes, and are taken care of locally within
1708 * finalize_primnode.)
1710 * Note: this is a bit overly generous since some parameters of upper
1711 * query levels might belong to query subtrees that don't include this
1712 * query. However, valid_params is only a debugging crosscheck, so it
1713 * doesn't seem worth expending lots of cycles to try to be exact.
1715 valid_params = bms_copy(initSetParam);
1717 foreach(l, root->glob->paramlist)
1719 PlannerParamItem *pitem = (PlannerParamItem *) lfirst(l);
1721 if (pitem->abslevel < root->query_level)
1723 /* valid outer-level parameter */
1724 valid_params = bms_add_member(valid_params, paramid);
1729 /* Also include the recursion working table, if any */
1730 if (root->wt_param_id >= 0)
1731 valid_params = bms_add_member(valid_params, root->wt_param_id);
1734 * Now recurse through plan tree.
1736 (void) finalize_plan(root, plan, valid_params);
1738 bms_free(valid_params);
1741 * Finally, attach any initPlans to the topmost plan node, and add their
1742 * extParams to the topmost node's, too. However, any setParams of the
1743 * initPlans should not be present in the topmost node's extParams, only
1744 * in its allParams. (As of PG 8.1, it's possible that some initPlans
1745 * have extParams that are setParams of other initPlans, so we have to
1746 * take care of this situation explicitly.)
1748 * We also add the eval cost of each initPlan to the startup cost of the
1749 * top node. This is a conservative overestimate, since in fact each
1750 * initPlan might be executed later than plan startup, or even not at all.
1752 if (attach_initplans)
1754 plan->initPlan = root->init_plans;
1755 root->init_plans = NIL; /* make sure they're not attached twice */
1757 /* allParam must include all these params */
1758 plan->allParam = bms_add_members(plan->allParam, initExtParam);
1759 plan->allParam = bms_add_members(plan->allParam, initSetParam);
1760 /* extParam must include any child extParam */
1761 plan->extParam = bms_add_members(plan->extParam, initExtParam);
1762 /* but extParam shouldn't include any setParams */
1763 plan->extParam = bms_del_members(plan->extParam, initSetParam);
1764 /* ensure extParam is exactly NULL if it's empty */
1765 if (bms_is_empty(plan->extParam))
1766 plan->extParam = NULL;
1768 plan->startup_cost += initplan_cost;
1769 plan->total_cost += initplan_cost;
1774 * Recursive processing of all nodes in the plan tree
1776 * The return value is the computed allParam set for the given Plan node.
1777 * This is just an internal notational convenience.
1780 finalize_plan(PlannerInfo *root, Plan *plan, Bitmapset *valid_params)
1782 finalize_primnode_context context;
1787 context.root = root;
1788 context.paramids = NULL; /* initialize set to empty */
1791 * When we call finalize_primnode, context.paramids sets are automatically
1792 * merged together. But when recursing to self, we have to do it the hard
1793 * way. We want the paramids set to include params in subplans as well as
1797 /* Find params in targetlist and qual */
1798 finalize_primnode((Node *) plan->targetlist, &context);
1799 finalize_primnode((Node *) plan->qual, &context);
1801 /* Check additional node-type-specific fields */
1802 switch (nodeTag(plan))
1805 finalize_primnode(((Result *) plan)->resconstantqual,
1810 finalize_primnode((Node *) ((IndexScan *) plan)->indexqual,
1814 * we need not look at indexqualorig, since it will have the same
1815 * param references as indexqual.
1819 case T_BitmapIndexScan:
1820 finalize_primnode((Node *) ((BitmapIndexScan *) plan)->indexqual,
1824 * we need not look at indexqualorig, since it will have the same
1825 * param references as indexqual.
1829 case T_BitmapHeapScan:
1830 finalize_primnode((Node *) ((BitmapHeapScan *) plan)->bitmapqualorig,
1835 finalize_primnode((Node *) ((TidScan *) plan)->tidquals,
1839 case T_SubqueryScan:
1842 * In a SubqueryScan, SS_finalize_plan has already been run on the
1843 * subplan by the inner invocation of subquery_planner, so there's
1844 * no need to do it again. Instead, just pull out the subplan's
1845 * extParams list, which represents the params it needs from my
1846 * level and higher levels.
1848 context.paramids = bms_add_members(context.paramids,
1849 ((SubqueryScan *) plan)->subplan->extParam);
1852 case T_FunctionScan:
1853 finalize_primnode(((FunctionScan *) plan)->funcexpr,
1858 finalize_primnode((Node *) ((ValuesScan *) plan)->values_lists,
1864 bms_add_member(context.paramids,
1865 ((CteScan *) plan)->cteParam);
1868 case T_WorkTableScan:
1870 bms_add_member(context.paramids,
1871 ((WorkTableScan *) plan)->wtParam);
1878 foreach(l, ((Append *) plan)->appendplans)
1881 bms_add_members(context.paramids,
1893 foreach(l, ((BitmapAnd *) plan)->bitmapplans)
1896 bms_add_members(context.paramids,
1908 foreach(l, ((BitmapOr *) plan)->bitmapplans)
1911 bms_add_members(context.paramids,
1920 finalize_primnode((Node *) ((Join *) plan)->joinqual,
1925 finalize_primnode((Node *) ((Join *) plan)->joinqual,
1927 finalize_primnode((Node *) ((MergeJoin *) plan)->mergeclauses,
1932 finalize_primnode((Node *) ((Join *) plan)->joinqual,
1934 finalize_primnode((Node *) ((HashJoin *) plan)->hashclauses,
1939 finalize_primnode(((Limit *) plan)->limitOffset,
1941 finalize_primnode(((Limit *) plan)->limitCount,
1945 case T_RecursiveUnion:
1958 elog(ERROR, "unrecognized node type: %d",
1959 (int) nodeTag(plan));
1962 /* Process left and right child plans, if any */
1963 context.paramids = bms_add_members(context.paramids,
1968 context.paramids = bms_add_members(context.paramids,
1974 * RecursiveUnion *generates* its worktable param, so don't bubble that up
1976 if (IsA(plan, RecursiveUnion))
1978 context.paramids = bms_del_member(context.paramids,
1979 ((RecursiveUnion *) plan)->wtParam);
1982 /* Now we have all the paramids */
1984 if (!bms_is_subset(context.paramids, valid_params))
1985 elog(ERROR, "plan should not reference subplan's variable");
1988 * Note: by definition, extParam and allParam should have the same value
1989 * in any plan node that doesn't have child initPlans. We set them
1990 * equal here, and later SS_finalize_plan will update them properly
1991 * in node(s) that it attaches initPlans to.
1993 * For speed at execution time, make sure extParam/allParam are actually
1994 * NULL if they are empty sets.
1996 if (bms_is_empty(context.paramids))
1998 plan->extParam = NULL;
1999 plan->allParam = NULL;
2003 plan->extParam = context.paramids;
2004 plan->allParam = bms_copy(context.paramids);
2007 return plan->allParam;
2011 * finalize_primnode: add IDs of all PARAM_EXEC params appearing in the given
2012 * expression tree to the result set.
2015 finalize_primnode(Node *node, finalize_primnode_context *context)
2019 if (IsA(node, Param))
2021 if (((Param *) node)->paramkind == PARAM_EXEC)
2023 int paramid = ((Param *) node)->paramid;
2025 context->paramids = bms_add_member(context->paramids, paramid);
2027 return false; /* no more to do here */
2029 if (IsA(node, SubPlan))
2031 SubPlan *subplan = (SubPlan *) node;
2032 Plan *plan = planner_subplan_get_plan(context->root, subplan);
2034 Bitmapset *subparamids;
2036 /* Recurse into the testexpr, but not into the Plan */
2037 finalize_primnode(subplan->testexpr, context);
2040 * Remove any param IDs of output parameters of the subplan that were
2041 * referenced in the testexpr. These are not interesting for
2042 * parameter change signaling since we always re-evaluate the subplan.
2043 * Note that this wouldn't work too well if there might be uses of the
2044 * same param IDs elsewhere in the plan, but that can't happen because
2045 * generate_new_param never tries to merge params.
2047 foreach(lc, subplan->paramIds)
2049 context->paramids = bms_del_member(context->paramids,
2053 /* Also examine args list */
2054 finalize_primnode((Node *) subplan->args, context);
2057 * Add params needed by the subplan to paramids, but excluding those
2058 * we will pass down to it.
2060 subparamids = bms_copy(plan->extParam);
2061 foreach(lc, subplan->parParam)
2063 subparamids = bms_del_member(subparamids, lfirst_int(lc));
2065 context->paramids = bms_join(context->paramids, subparamids);
2067 return false; /* no more to do here */
2069 return expression_tree_walker(node, finalize_primnode,
2074 * SS_make_initplan_from_plan - given a plan tree, make it an InitPlan
2076 * The plan is expected to return a scalar value of the indicated type.
2077 * We build an EXPR_SUBLINK SubPlan node and put it into the initplan
2078 * list for the current query level. A Param that represents the initplan's
2079 * output is returned.
2081 * We assume the plan hasn't been put through SS_finalize_plan.
2084 SS_make_initplan_from_plan(PlannerInfo *root, Plan *plan,
2085 Oid resulttype, int32 resulttypmod)
2091 * We must run SS_finalize_plan(), since that's normally done before a
2092 * subplan gets put into the initplan list. Tell it not to attach any
2093 * pre-existing initplans to this one, since they are siblings not
2094 * children of this initplan. (This is something else that could perhaps
2095 * be cleaner if we did extParam/allParam processing in setrefs.c instead
2096 * of here? See notes for materialize_finished_plan.)
2100 * Build extParam/allParam sets for plan nodes.
2102 SS_finalize_plan(root, plan, false);
2105 * Add the subplan and its rtable to the global lists.
2107 root->glob->subplans = lappend(root->glob->subplans,
2109 root->glob->subrtables = lappend(root->glob->subrtables,
2110 root->parse->rtable);
2113 * Create a SubPlan node and add it to the outer list of InitPlans.
2114 * Note it has to appear after any other InitPlans it might depend on
2115 * (see comments in ExecReScan).
2117 node = makeNode(SubPlan);
2118 node->subLinkType = EXPR_SUBLINK;
2119 get_first_col_type(plan, &node->firstColType, &node->firstColTypmod);
2120 node->plan_id = list_length(root->glob->subplans);
2122 root->init_plans = lappend(root->init_plans, node);
2125 * The node can't have any inputs (since it's an initplan), so the
2126 * parParam and args lists remain empty.
2129 cost_subplan(root, node, plan);
2132 * Make a Param that will be the subplan's output.
2134 prm = generate_new_param(root, resulttype, resulttypmod);
2135 node->setParam = list_make1_int(prm->paramid);