Reconsider mechanism for marking sub-selects that are at top level of
a qualification clause (and hence can get away with being sloppy about distinguishing FALSE from UNKNOWN). We need to know this in subselect.c; marking the subplans in setrefs.c is too late.
This commit is contained in:
Tom Lane
parent
de432ce39e
commit
56e1aab286
@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.137 2003/01/13 00:29:25 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.138 2003/01/13 18:10:53 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -777,7 +777,7 @@ preprocess_expression(Query *parse, Node *expr, int kind)
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/* Expand SubLinks to SubPlans */
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if (parse->hasSubLinks)
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expr = SS_process_sublinks(expr);
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expr = SS_process_sublinks(expr, (kind != EXPRKIND_TARGET));
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/* Replace uplevel vars with Param nodes */
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if (PlannerQueryLevel > 1)
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@ -9,7 +9,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/setrefs.c,v 1.87 2003/01/10 21:08:11 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/setrefs.c,v 1.88 2003/01/13 18:10:53 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -42,7 +42,6 @@ typedef struct
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static void fix_expr_references(Plan *plan, Node *node);
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static bool fix_expr_references_walker(Node *node, void *context);
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static void mark_qual_expressions(List *quals);
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static void set_join_references(Join *join, List *rtable);
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static void set_uppernode_references(Plan *plan, Index subvarno);
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static Node *join_references_mutator(Node *node,
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@ -89,12 +88,10 @@ set_plan_references(Plan *plan, List *rtable)
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case T_SeqScan:
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fix_expr_references(plan, (Node *) plan->targetlist);
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fix_expr_references(plan, (Node *) plan->qual);
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mark_qual_expressions(plan->qual);
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break;
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case T_IndexScan:
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fix_expr_references(plan, (Node *) plan->targetlist);
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fix_expr_references(plan, (Node *) plan->qual);
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mark_qual_expressions(plan->qual);
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fix_expr_references(plan,
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(Node *) ((IndexScan *) plan)->indxqual);
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fix_expr_references(plan,
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@ -103,7 +100,6 @@ set_plan_references(Plan *plan, List *rtable)
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case T_TidScan:
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fix_expr_references(plan, (Node *) plan->targetlist);
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fix_expr_references(plan, (Node *) plan->qual);
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mark_qual_expressions(plan->qual);
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fix_expr_references(plan,
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(Node *) ((TidScan *) plan)->tideval);
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break;
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@ -118,7 +114,6 @@ set_plan_references(Plan *plan, List *rtable)
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*/
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fix_expr_references(plan, (Node *) plan->targetlist);
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fix_expr_references(plan, (Node *) plan->qual);
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mark_qual_expressions(plan->qual);
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/* Recurse into subplan too */
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rte = rt_fetch(((SubqueryScan *) plan)->scan.scanrelid,
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@ -134,7 +129,6 @@ set_plan_references(Plan *plan, List *rtable)
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fix_expr_references(plan, (Node *) plan->targetlist);
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fix_expr_references(plan, (Node *) plan->qual);
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mark_qual_expressions(plan->qual);
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rte = rt_fetch(((FunctionScan *) plan)->scan.scanrelid,
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rtable);
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Assert(rte->rtekind == RTE_FUNCTION);
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@ -145,17 +139,13 @@ set_plan_references(Plan *plan, List *rtable)
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set_join_references((Join *) plan, rtable);
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fix_expr_references(plan, (Node *) plan->targetlist);
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fix_expr_references(plan, (Node *) plan->qual);
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mark_qual_expressions(plan->qual);
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fix_expr_references(plan, (Node *) ((Join *) plan)->joinqual);
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mark_qual_expressions(((Join *) plan)->joinqual);
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break;
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case T_MergeJoin:
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set_join_references((Join *) plan, rtable);
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fix_expr_references(plan, (Node *) plan->targetlist);
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fix_expr_references(plan, (Node *) plan->qual);
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mark_qual_expressions(plan->qual);
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fix_expr_references(plan, (Node *) ((Join *) plan)->joinqual);
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mark_qual_expressions(((Join *) plan)->joinqual);
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fix_expr_references(plan,
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(Node *) ((MergeJoin *) plan)->mergeclauses);
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break;
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@ -163,9 +153,7 @@ set_plan_references(Plan *plan, List *rtable)
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set_join_references((Join *) plan, rtable);
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fix_expr_references(plan, (Node *) plan->targetlist);
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fix_expr_references(plan, (Node *) plan->qual);
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mark_qual_expressions(plan->qual);
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fix_expr_references(plan, (Node *) ((Join *) plan)->joinqual);
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mark_qual_expressions(((Join *) plan)->joinqual);
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fix_expr_references(plan,
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(Node *) ((HashJoin *) plan)->hashclauses);
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break;
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@ -192,7 +180,6 @@ set_plan_references(Plan *plan, List *rtable)
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set_uppernode_references(plan, (Index) 0);
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fix_expr_references(plan, (Node *) plan->targetlist);
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fix_expr_references(plan, (Node *) plan->qual);
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mark_qual_expressions(plan->qual);
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break;
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case T_Result:
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@ -206,9 +193,7 @@ set_plan_references(Plan *plan, List *rtable)
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set_uppernode_references(plan, (Index) OUTER);
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fix_expr_references(plan, (Node *) plan->targetlist);
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fix_expr_references(plan, (Node *) plan->qual);
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mark_qual_expressions(plan->qual);
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fix_expr_references(plan, ((Result *) plan)->resconstantqual);
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mark_qual_expressions((List *) ((Result *) plan)->resconstantqual);
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break;
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case T_Append:
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@ -283,28 +268,6 @@ fix_expr_references_walker(Node *node, void *context)
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return expression_tree_walker(node, fix_expr_references_walker, context);
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}
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/*
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* mark_qual_expressions
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* Do final cleanup on qualifier expressions (not targetlists!)
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*
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* SubPlans appearing at the top level of a qual expression are marked
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* to indicate that they need not distinguish UNKNOWN (null) from FALSE
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* results; this can save processing time in some cases.
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*/
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static void
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mark_qual_expressions(List *quals)
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{
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List *qual;
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foreach(qual, quals)
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{
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Node *node = lfirst(qual);
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if (IsA(node, SubPlan))
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((SubPlan *) node)->unknownEqFalse = true;
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}
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}
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/*
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* set_join_references
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* Modifies the target list of a join node to reference its subplans,
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@ -7,7 +7,7 @@
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.65 2003/01/13 00:29:26 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.66 2003/01/13 18:10:53 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -65,7 +65,7 @@ static List *convert_sublink_opers(List *lefthand, List *operOids,
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List *targetlist, List **paramIds);
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static bool subplan_is_hashable(SubLink *slink, SubPlan *node);
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static Node *replace_correlation_vars_mutator(Node *node, void *context);
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static Node *process_sublinks_mutator(Node *node, void *context);
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static Node *process_sublinks_mutator(Node *node, bool *isTopQual);
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static bool finalize_primnode(Node *node, finalize_primnode_results *results);
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@ -159,7 +159,8 @@ generate_new_param(Oid paramtype, int32 paramtypmod)
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* Convert a bare SubLink (as created by the parser) into a SubPlan.
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*
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* We are given the raw SubLink and the already-processed lefthand argument
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* list (use this instead of the SubLink's own field).
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* list (use this instead of the SubLink's own field). We are also told if
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* this expression appears at top level of a WHERE/HAVING qual.
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*
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* The result is whatever we need to substitute in place of the SubLink
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* node in the executable expression. This will be either the SubPlan
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@ -168,7 +169,7 @@ generate_new_param(Oid paramtype, int32 paramtypmod)
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* containing InitPlan Param nodes.
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*/
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static Node *
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make_subplan(SubLink *slink, List *lefthand)
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make_subplan(SubLink *slink, List *lefthand, bool isTopQual)
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{
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SubPlan *node = makeNode(SubPlan);
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Query *subquery = (Query *) (slink->subselect);
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@ -232,7 +233,8 @@ make_subplan(SubLink *slink, List *lefthand)
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node->exprs = NIL;
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node->paramIds = NIL;
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node->useHashTable = false;
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node->unknownEqFalse = false;
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/* At top level of a qual, can treat UNKNOWN the same as FALSE */
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node->unknownEqFalse = isTopQual;
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node->setParam = NIL;
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node->parParam = NIL;
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node->args = NIL;
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@ -589,17 +591,23 @@ replace_correlation_vars_mutator(Node *node, void *context)
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/*
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* Expand SubLinks to SubPlans in the given expression.
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*
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* The isQual argument tells whether or not this expression is a WHERE/HAVING
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* qualifier expression. If it is, any sublinks appearing at top level need
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* not distinguish FALSE from UNKNOWN return values.
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*/
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Node *
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SS_process_sublinks(Node *expr)
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SS_process_sublinks(Node *expr, bool isQual)
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{
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/* No setup needed for tree walk, so away we go */
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return process_sublinks_mutator(expr, NULL);
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/* The only context needed is the initial are-we-in-a-qual flag */
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return process_sublinks_mutator(expr, &isQual);
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}
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static Node *
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process_sublinks_mutator(Node *node, void *context)
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process_sublinks_mutator(Node *node, bool *isTopQual)
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{
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bool locTopQual;
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if (node == NULL)
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return NULL;
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if (IsA(node, SubLink))
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@ -610,12 +618,13 @@ process_sublinks_mutator(Node *node, void *context)
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/*
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* First, recursively process the lefthand-side expressions, if any.
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*/
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locTopQual = false;
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lefthand = (List *)
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process_sublinks_mutator((Node *) sublink->lefthand, context);
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process_sublinks_mutator((Node *) sublink->lefthand, &locTopQual);
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/*
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* Now build the SubPlan node and make the expr to return.
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*/
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return make_subplan(sublink, lefthand);
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return make_subplan(sublink, lefthand, *isTopQual);
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}
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/*
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@ -626,9 +635,18 @@ process_sublinks_mutator(Node *node, void *context)
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*/
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Assert(!is_subplan(node));
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/*
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* If we recurse down through anything other than a List node, we are
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* definitely not at top qual level anymore.
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*/
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if (IsA(node, List))
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locTopQual = *isTopQual;
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else
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locTopQual = false;
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return expression_tree_mutator(node,
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process_sublinks_mutator,
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context);
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(void *) &locTopQual);
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}
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/*
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@ -16,6 +16,6 @@ extern int PlannerPlanId; /* to assign unique ID to subquery plans */
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extern List *SS_finalize_plan(Plan *plan, List *rtable);
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extern Node *SS_replace_correlation_vars(Node *expr);
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extern Node *SS_process_sublinks(Node *expr);
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extern Node *SS_process_sublinks(Node *expr, bool isQual);
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#endif /* SUBSELECT_H */
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