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Commit 56e1aab2 authored by Tom Lane's avatar Tom Lane
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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.
parent de432ce3
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src/backend/optimizer/plan/planner.c
+ 2
− 2
View file @ 56e1aab2
......@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.137 2003/01/13 00:29:25 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.138 2003/01/13 18:10:53 tgl Exp $
*
*-------------------------------------------------------------------------
*/
......@@ -777,7 +777,7 @@ preprocess_expression(Query *parse, Node *expr, int kind)
/* Expand SubLinks to SubPlans */
if (parse->hasSubLinks)
expr = SS_process_sublinks(expr);
expr = SS_process_sublinks(expr, (kind != EXPRKIND_TARGET));
/* Replace uplevel vars with Param nodes */
if (PlannerQueryLevel > 1)
......
src/backend/optimizer/plan/setrefs.c
+ 1
− 38
View file @ 56e1aab2
......@@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/setrefs.c,v 1.87 2003/01/10 21:08:11 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/setrefs.c,v 1.88 2003/01/13 18:10:53 tgl Exp $
*
*-------------------------------------------------------------------------
*/
......@@ -42,7 +42,6 @@ typedef struct
static void fix_expr_references(Plan *plan, Node *node);
static bool fix_expr_references_walker(Node *node, void *context);
static void mark_qual_expressions(List *quals);
static void set_join_references(Join *join, List *rtable);
static void set_uppernode_references(Plan *plan, Index subvarno);
static Node *join_references_mutator(Node *node,
......@@ -89,12 +88,10 @@ set_plan_references(Plan *plan, List *rtable)
case T_SeqScan:
fix_expr_references(plan, (Node *) plan->targetlist);
fix_expr_references(plan, (Node *) plan->qual);
mark_qual_expressions(plan->qual);
break;
case T_IndexScan:
fix_expr_references(plan, (Node *) plan->targetlist);
fix_expr_references(plan, (Node *) plan->qual);
mark_qual_expressions(plan->qual);
fix_expr_references(plan,
(Node *) ((IndexScan *) plan)->indxqual);
fix_expr_references(plan,
......@@ -103,7 +100,6 @@ set_plan_references(Plan *plan, List *rtable)
case T_TidScan:
fix_expr_references(plan, (Node *) plan->targetlist);
fix_expr_references(plan, (Node *) plan->qual);
mark_qual_expressions(plan->qual);
fix_expr_references(plan,
(Node *) ((TidScan *) plan)->tideval);
break;
......@@ -118,7 +114,6 @@ set_plan_references(Plan *plan, List *rtable)
*/
fix_expr_references(plan, (Node *) plan->targetlist);
fix_expr_references(plan, (Node *) plan->qual);
mark_qual_expressions(plan->qual);
/* Recurse into subplan too */
rte = rt_fetch(((SubqueryScan *) plan)->scan.scanrelid,
......@@ -134,7 +129,6 @@ set_plan_references(Plan *plan, List *rtable)
fix_expr_references(plan, (Node *) plan->targetlist);
fix_expr_references(plan, (Node *) plan->qual);
mark_qual_expressions(plan->qual);
rte = rt_fetch(((FunctionScan *) plan)->scan.scanrelid,
rtable);
Assert(rte->rtekind == RTE_FUNCTION);
......@@ -145,17 +139,13 @@ set_plan_references(Plan *plan, List *rtable)
set_join_references((Join *) plan, rtable);
fix_expr_references(plan, (Node *) plan->targetlist);
fix_expr_references(plan, (Node *) plan->qual);
mark_qual_expressions(plan->qual);
fix_expr_references(plan, (Node *) ((Join *) plan)->joinqual);
mark_qual_expressions(((Join *) plan)->joinqual);
break;
case T_MergeJoin:
set_join_references((Join *) plan, rtable);
fix_expr_references(plan, (Node *) plan->targetlist);
fix_expr_references(plan, (Node *) plan->qual);
mark_qual_expressions(plan->qual);
fix_expr_references(plan, (Node *) ((Join *) plan)->joinqual);
mark_qual_expressions(((Join *) plan)->joinqual);
fix_expr_references(plan,
(Node *) ((MergeJoin *) plan)->mergeclauses);
break;
......@@ -163,9 +153,7 @@ set_plan_references(Plan *plan, List *rtable)
set_join_references((Join *) plan, rtable);
fix_expr_references(plan, (Node *) plan->targetlist);
fix_expr_references(plan, (Node *) plan->qual);
mark_qual_expressions(plan->qual);
fix_expr_references(plan, (Node *) ((Join *) plan)->joinqual);
mark_qual_expressions(((Join *) plan)->joinqual);
fix_expr_references(plan,
(Node *) ((HashJoin *) plan)->hashclauses);
break;
......@@ -192,7 +180,6 @@ set_plan_references(Plan *plan, List *rtable)
set_uppernode_references(plan, (Index) 0);
fix_expr_references(plan, (Node *) plan->targetlist);
fix_expr_references(plan, (Node *) plan->qual);
mark_qual_expressions(plan->qual);
break;
case T_Result:
......@@ -206,9 +193,7 @@ set_plan_references(Plan *plan, List *rtable)
set_uppernode_references(plan, (Index) OUTER);
fix_expr_references(plan, (Node *) plan->targetlist);
fix_expr_references(plan, (Node *) plan->qual);
mark_qual_expressions(plan->qual);
fix_expr_references(plan, ((Result *) plan)->resconstantqual);
mark_qual_expressions((List *) ((Result *) plan)->resconstantqual);
break;
case T_Append:
......@@ -283,28 +268,6 @@ fix_expr_references_walker(Node *node, void *context)
return expression_tree_walker(node, fix_expr_references_walker, context);
}
/*
* mark_qual_expressions
* Do final cleanup on qualifier expressions (not targetlists!)
*
* SubPlans appearing at the top level of a qual expression are marked
* to indicate that they need not distinguish UNKNOWN (null) from FALSE
* results; this can save processing time in some cases.
*/
static void
mark_qual_expressions(List *quals)
{
List *qual;
foreach(qual, quals)
{
Node *node = lfirst(qual);
if (IsA(node, SubPlan))
((SubPlan *) node)->unknownEqFalse = true;
}
}
/*
* set_join_references
* Modifies the target list of a join node to reference its subplans,
......
src/backend/optimizer/plan/subselect.c
+ 30
− 12
View file @ 56e1aab2
......@@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.65 2003/01/13 00:29:26 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.66 2003/01/13 18:10:53 tgl Exp $
*
*-------------------------------------------------------------------------
*/
......@@ -65,7 +65,7 @@ static List *convert_sublink_opers(List *lefthand, List *operOids,
List *targetlist, List **paramIds);
static bool subplan_is_hashable(SubLink *slink, SubPlan *node);
static Node *replace_correlation_vars_mutator(Node *node, void *context);
static Node *process_sublinks_mutator(Node *node, void *context);
static Node *process_sublinks_mutator(Node *node, bool *isTopQual);
static bool finalize_primnode(Node *node, finalize_primnode_results *results);
......@@ -159,7 +159,8 @@ generate_new_param(Oid paramtype, int32 paramtypmod)
* Convert a bare SubLink (as created by the parser) into a SubPlan.
*
* We are given the raw SubLink and the already-processed lefthand argument
* list (use this instead of the SubLink's own field).
* list (use this instead of the SubLink's own field). We are also told if
* this expression appears at top level of a WHERE/HAVING qual.
*
* The result is whatever we need to substitute in place of the SubLink
* node in the executable expression. This will be either the SubPlan
......@@ -168,7 +169,7 @@ generate_new_param(Oid paramtype, int32 paramtypmod)
* containing InitPlan Param nodes.
*/
static Node *
make_subplan(SubLink *slink, List *lefthand)
make_subplan(SubLink *slink, List *lefthand, bool isTopQual)
{
SubPlan *node = makeNode(SubPlan);
Query *subquery = (Query *) (slink->subselect);
......@@ -232,7 +233,8 @@ make_subplan(SubLink *slink, List *lefthand)
node->exprs = NIL;
node->paramIds = NIL;
node->useHashTable = false;
node->unknownEqFalse = false;
/* At top level of a qual, can treat UNKNOWN the same as FALSE */
node->unknownEqFalse = isTopQual;
node->setParam = NIL;
node->parParam = NIL;
node->args = NIL;
......@@ -589,17 +591,23 @@ replace_correlation_vars_mutator(Node *node, void *context)
/*
* Expand SubLinks to SubPlans in the given expression.
*
* The isQual argument tells whether or not this expression is a WHERE/HAVING
* qualifier expression. If it is, any sublinks appearing at top level need
* not distinguish FALSE from UNKNOWN return values.
*/
Node *
SS_process_sublinks(Node *expr)
SS_process_sublinks(Node *expr, bool isQual)
{
/* No setup needed for tree walk, so away we go */
return process_sublinks_mutator(expr, NULL);
/* The only context needed is the initial are-we-in-a-qual flag */
return process_sublinks_mutator(expr, &isQual);
}
static Node *
process_sublinks_mutator(Node *node, void *context)
process_sublinks_mutator(Node *node, bool *isTopQual)
{
bool locTopQual;
if (node == NULL)
return NULL;
if (IsA(node, SubLink))
......@@ -610,12 +618,13 @@ process_sublinks_mutator(Node *node, void *context)
/*
* First, recursively process the lefthand-side expressions, if any.
*/
locTopQual = false;
lefthand = (List *)
process_sublinks_mutator((Node *) sublink->lefthand, context);
process_sublinks_mutator((Node *) sublink->lefthand, &locTopQual);
/*
* Now build the SubPlan node and make the expr to return.
*/
return make_subplan(sublink, lefthand);
return make_subplan(sublink, lefthand, *isTopQual);
}
/*
......@@ -626,9 +635,18 @@ process_sublinks_mutator(Node *node, void *context)
*/
Assert(!is_subplan(node));
/*
* If we recurse down through anything other than a List node, we are
* definitely not at top qual level anymore.
*/
if (IsA(node, List))
locTopQual = *isTopQual;
else
locTopQual = false;
return expression_tree_mutator(node,
process_sublinks_mutator,
context);
(void *) &locTopQual);
}
/*
......
src/include/optimizer/subselect.h
+ 1
− 1
View file @ 56e1aab2
......@@ -16,6 +16,6 @@ extern int PlannerPlanId; /* to assign unique ID to subquery plans */
extern List *SS_finalize_plan(Plan *plan, List *rtable);
extern Node *SS_replace_correlation_vars(Node *expr);
extern Node *SS_process_sublinks(Node *expr);
extern Node *SS_process_sublinks(Node *expr, bool isQual);
#endif /* SUBSELECT_H */
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