Clean up rewriter routines to use expression_tree_walker and
expression_tree_mutator rather than ad-hoc tree walking code. This shortens the code materially and fixes a fair number of sins of omission. Also, change modifyAggrefQual to *not* recurse into subselects, since its mission is satisfied if it removes aggregate functions from the top level of a WHERE clause. This cures problems with queries of the form SELECT ... WHERE x IN (SELECT ... HAVING something-using-an-aggregate), which would formerly get mucked up by modifyAggrefQual. The routine is still fundamentally broken, of course, but I don't think there's any way to get rid of it before we implement subselects in FROM ...
This commit is contained in:
Tom Lane
parent
ce1f5ed547
commit
389af07cf0
@ -6,7 +6,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/rewrite/Attic/locks.c,v 1.22 1999/09/18 19:07:18 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/rewrite/Attic/locks.c,v 1.23 1999/10/01 04:08:24 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -14,6 +14,7 @@
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#include "access/heapam.h"
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#include "catalog/pg_shadow.h"
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#include "optimizer/clauses.h"
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#include "rewrite/locks.h"
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#include "utils/acl.h"
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#include "utils/builtins.h"
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@ -22,102 +23,86 @@
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/*
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* ThisLockWasTriggered
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* thisLockWasTriggered
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*
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* walk the tree, if there we find a varnode,
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* we check the varattno against the attnum
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* if we find at least one such match, we return true
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* otherwise, we return false
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*
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* XXX this should be unified with attribute_used()
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*/
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typedef struct {
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int varno;
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int attnum;
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int sublevels_up;
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} thisLockWasTriggered_context;
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static bool
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nodeThisLockWasTriggered(Node *node, int varno, AttrNumber attnum,
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int sublevels_up)
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thisLockWasTriggered_walker (Node *node,
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thisLockWasTriggered_context *context)
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{
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if (node == NULL)
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return FALSE;
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switch (nodeTag(node))
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return false;
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if (IsA(node, Var))
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{
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case T_Var:
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{
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Var *var = (Var *) node;
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Var *var = (Var *) node;
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if (varno == var->varno &&
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(attnum == var->varattno || attnum == -1))
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return TRUE;
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}
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break;
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case T_Expr:
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{
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Expr *expr = (Expr *) node;
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return nodeThisLockWasTriggered((Node *) expr->args, varno,
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attnum, sublevels_up);
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}
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break;
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case T_TargetEntry:
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{
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TargetEntry *tle = (TargetEntry *) node;
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return nodeThisLockWasTriggered(tle->expr, varno, attnum,
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sublevels_up);
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}
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break;
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case T_Aggref:
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{
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Aggref *aggref = (Aggref *) node;
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return nodeThisLockWasTriggered(aggref->target, varno, attnum,
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sublevels_up);
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}
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break;
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case T_List:
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{
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List *l;
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foreach(l, (List *) node)
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{
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if (nodeThisLockWasTriggered(lfirst(l), varno, attnum,
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sublevels_up))
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return TRUE;
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}
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return FALSE;
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}
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break;
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case T_SubLink:
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{
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SubLink *sublink = (SubLink *) node;
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Query *query = (Query *) sublink->subselect;
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return nodeThisLockWasTriggered(query->qual, varno, attnum,
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sublevels_up + 1);
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}
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break;
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default:
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break;
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if (var->varlevelsup == context->sublevels_up &&
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var->varno == context->varno &&
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(var->varattno == context->attnum || context->attnum == -1))
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return true;
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return false;
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}
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return FALSE;
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if (IsA(node, SubLink))
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{
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/*
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* Standard expression_tree_walker will not recurse into subselect,
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* but here we must do so.
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*/
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SubLink *sub = (SubLink *) node;
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if (thisLockWasTriggered_walker((Node *) (sub->lefthand), context))
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return true;
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context->sublevels_up++;
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if (thisLockWasTriggered_walker((Node *) (sub->subselect), context))
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{
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context->sublevels_up--; /* not really necessary */
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return true;
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}
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context->sublevels_up--;
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return false;
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}
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if (IsA(node, Query))
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{
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/* Reach here after recursing down into subselect above... */
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Query *qry = (Query *) node;
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if (thisLockWasTriggered_walker((Node *) (qry->targetList), context))
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return true;
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if (thisLockWasTriggered_walker((Node *) (qry->qual), context))
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return true;
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if (thisLockWasTriggered_walker((Node *) (qry->havingQual), context))
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return true;
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return false;
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}
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return expression_tree_walker(node, thisLockWasTriggered_walker,
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(void *) context);
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}
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/*
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* thisLockWasTriggered -
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* walk the tree, if there we find a varnode, we check the varattno
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* against the attnum if we find at least one such match, we return true
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* otherwise, we return false
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*/
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static bool
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thisLockWasTriggered(int varno,
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AttrNumber attnum,
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int attnum,
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Query *parsetree)
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{
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thisLockWasTriggered_context context;
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if (nodeThisLockWasTriggered(parsetree->qual, varno, attnum, 0))
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return true;
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if (nodeThisLockWasTriggered((Node *) parsetree->targetList, varno, attnum, 0))
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return true;
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return false;
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context.varno = varno;
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context.attnum = attnum;
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context.sublevels_up = 0;
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return thisLockWasTriggered_walker((Node *) parsetree, &context);
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}
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/*
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File diff suppressed because it is too large
Load Diff
File diff suppressed because it is too large
Load Diff
@ -6,7 +6,7 @@
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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* $Id: rewriteManip.h,v 1.17 1999/07/15 15:21:30 momjian Exp $
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* $Id: rewriteManip.h,v 1.18 1999/10/01 04:08:15 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -16,19 +16,18 @@
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#include "rewrite/rewriteHandler.h"
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/* RewriteManip.c */
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void OffsetVarNodes(Node *node, int offset, int sublevels_up);
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void ChangeVarNodes(Node *node, int old_varno, int new_varno,
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int sublevels_up);
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void AddQual(Query *parsetree, Node *qual);
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void AddHavingQual(Query *parsetree, Node *havingQual);
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extern void OffsetVarNodes(Node *node, int offset, int sublevels_up);
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extern void ChangeVarNodes(Node *node, int old_varno, int new_varno,
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int sublevels_up);
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extern void AddQual(Query *parsetree, Node *qual);
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extern void AddHavingQual(Query *parsetree, Node *havingQual);
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extern void AddNotQual(Query *parsetree, Node *qual);
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extern void AddGroupClause(Query *parsetree, List *group_by, List *tlist);
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void AddNotQual(Query *parsetree, Node *qual);
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void AddGroupClause(Query *parsetree, List *group_by, List *tlist);
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extern void FixNew(RewriteInfo *info, Query *parsetree);
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void FixNew(RewriteInfo *info, Query *parsetree);
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void HandleRIRAttributeRule(Query *parsetree, List *rtable, List *targetlist,
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int rt_index, int attr_num, int *modified,
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int *badpostquel);
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extern void HandleRIRAttributeRule(Query *parsetree, List *rtable,
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List *targetlist, int rt_index,
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int attr_num, int *modified, int *badsql);
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#endif /* REWRITEMANIP_H */
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