Cache eval cost of qualification expressions in RestrictInfo nodes to
avoid repeated evaluations in cost_qual_eval(). This turns out to save a useful fraction of planning time. No change to external representation of RestrictInfo --- although that node type doesn't appear in stored rules anyway.
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77c443f8cd
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7 changed files with 54 additions and 24 deletions
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@ -15,7 +15,7 @@
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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/nodes/copyfuncs.c,v 1.133 2000/11/24 20:16:39 petere Exp $
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* $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.134 2000/12/12 23:33:32 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -1418,6 +1418,7 @@ _copyRestrictInfo(RestrictInfo *from)
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* ----------------
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*/
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Node_Copy(from, newnode, clause);
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newnode->eval_cost = from->eval_cost;
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newnode->ispusheddown = from->ispusheddown;
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Node_Copy(from, newnode, subclauseindices);
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newnode->mergejoinoperator = from->mergejoinoperator;
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@ -20,7 +20,7 @@
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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/nodes/equalfuncs.c,v 1.83 2000/11/24 20:16:39 petere Exp $
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* $Header: /cvsroot/pgsql/src/backend/nodes/equalfuncs.c,v 1.84 2000/12/12 23:33:33 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -514,6 +514,10 @@ _equalRestrictInfo(RestrictInfo *a, RestrictInfo *b)
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{
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if (!equal(a->clause, b->clause))
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return false;
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/*
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* ignore eval_cost, since it may not be set yet, and should be
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* derivable from the clause anyway
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*/
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if (a->ispusheddown != b->ispusheddown)
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return false;
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if (!equal(a->subclauseindices, b->subclauseindices))
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@ -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/nodes/readfuncs.c,v 1.100 2000/11/12 00:36:57 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/nodes/readfuncs.c,v 1.101 2000/12/12 23:33:33 tgl Exp $
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*
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* NOTES
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* Most of the read functions for plan nodes are tested. (In fact, they
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@ -1846,6 +1846,9 @@ _readRestrictInfo(void)
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token = lsptok(NULL, &length); /* now read it */
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local_node->hashjoinoperator = (Oid) atol(token);
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/* eval_cost is not part of saved representation; compute on first use */
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local_node->eval_cost = -1;
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return local_node;
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}
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@ -42,7 +42,7 @@
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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/path/costsize.c,v 1.64 2000/10/05 19:48:26 momjian Exp $
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* $Header: /cvsroot/pgsql/src/backend/optimizer/path/costsize.c,v 1.65 2000/12/12 23:33:33 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -672,8 +672,38 @@ Cost
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cost_qual_eval(List *quals)
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{
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Cost total = 0;
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List *l;
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cost_qual_eval_walker((Node *) quals, &total);
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/* We don't charge any cost for the implicit ANDing at top level ... */
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foreach(l, quals)
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{
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Node *qual = (Node *) lfirst(l);
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/*
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* RestrictInfo nodes contain an eval_cost field reserved for this
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* routine's use, so that it's not necessary to evaluate the qual
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* clause's cost more than once. If the clause's cost hasn't been
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* computed yet, the field will contain -1.
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*/
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if (qual && IsA(qual, RestrictInfo))
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{
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RestrictInfo *restrictinfo = (RestrictInfo *) qual;
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if (restrictinfo->eval_cost < 0)
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{
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restrictinfo->eval_cost = 0;
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cost_qual_eval_walker((Node *) restrictinfo->clause,
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&restrictinfo->eval_cost);
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}
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total += restrictinfo->eval_cost;
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}
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else
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{
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/* If it's a bare expression, must always do it the hard way */
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cost_qual_eval_walker(qual, &total);
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}
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}
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return total;
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}
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@ -748,18 +778,6 @@ cost_qual_eval_walker(Node *node, Cost *total)
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}
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/* fall through to examine args of Expr node */
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}
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/*
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* expression_tree_walker doesn't know what to do with RestrictInfo
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* nodes, but we just want to recurse through them.
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*/
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if (IsA(node, RestrictInfo))
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{
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RestrictInfo *restrictinfo = (RestrictInfo *) node;
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return cost_qual_eval_walker((Node *) restrictinfo->clause, total);
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}
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/* Otherwise, recurse. */
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return expression_tree_walker(node, cost_qual_eval_walker,
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(void *) total);
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}
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@ -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/initsplan.c,v 1.53 2000/11/23 03:57:31 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/initsplan.c,v 1.54 2000/12/12 23:33:33 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -338,6 +338,7 @@ distribute_qual_to_rels(Query *root, Node *clause,
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bool can_be_equijoin;
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restrictinfo->clause = (Expr *) clause;
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restrictinfo->eval_cost = -1; /* not computed until needed */
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restrictinfo->subclauseindices = NIL;
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restrictinfo->mergejoinoperator = InvalidOid;
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restrictinfo->left_sortop = InvalidOid;
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@ -14,7 +14,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/optimizer/prep/prepunion.c,v 1.56 2000/11/12 00:36:59 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/optimizer/prep/prepunion.c,v 1.57 2000/12/12 23:33:34 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -652,7 +652,7 @@ adjust_inherited_attrs_mutator(Node *node,
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/*
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* We have to process RestrictInfo nodes specially: we do NOT want to
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* copy the original subclauseindices list, since the new rel may have
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* different indices. The list will be rebuilt during planning anyway.
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* different indices. The list will be rebuilt during later planning.
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*/
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if (IsA(node, RestrictInfo))
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{
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@ -666,6 +666,7 @@ adjust_inherited_attrs_mutator(Node *node,
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adjust_inherited_attrs_mutator((Node *) oldinfo->clause, context);
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newinfo->subclauseindices = NIL;
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newinfo->eval_cost = -1; /* reset this too */
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return (Node *) newinfo;
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}
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@ -7,7 +7,7 @@
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* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $Id: relation.h,v 1.50 2000/11/12 00:37:01 tgl Exp $
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* $Id: relation.h,v 1.51 2000/12/12 23:33:32 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -373,9 +373,9 @@ typedef JoinPath NestPath;
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* A mergejoin path has these fields.
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*
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* path_mergeclauses lists the clauses (in the form of RestrictInfos)
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* that will be used in the merge. (Before 7.0, this was a list of
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* bare clause expressions, but we can save on list memory by leaving
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* it in the form of a RestrictInfo list.)
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* that will be used in the merge. (Before 7.0, this was a list of bare
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* clause expressions, but we can save on list memory and cost_qual_eval
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* work by leaving it in the form of a RestrictInfo list.)
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*
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* Note that the mergeclauses are a subset of the parent relation's
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* restriction-clause list. Any join clauses that are not mergejoinable
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@ -491,6 +491,8 @@ typedef struct RestrictInfo
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Expr *clause; /* the represented clause of WHERE or JOIN */
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Cost eval_cost; /* eval cost of clause; -1 if not yet set */
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bool ispusheddown; /* TRUE if clause was pushed down in level */
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/* only used if clause is an OR clause: */
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