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Make subqueries rewrite properly.

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This commit is contained in:
Bruce Momjian
1998-01-21 04:24:46 +00:00
parent 7e46348e62
commit 0f413d2dc2
4 changed files with 237 additions and 106 deletions
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100
src/backend/rewrite/rewriteHandler.c
View File

@ -6,7 +6,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.10 1998/01/09 05:48:17 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.11 1998/01/21 04:24:36 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -29,12 +29,12 @@
#include "commands/creatinh.h"
#include "access/heapam.h"
static void
ApplyRetrieveRule(Query *parsetree, RewriteRule *rule,
static void ApplyRetrieveRule(Query *parsetree, RewriteRule *rule,
int rt_index, int relation_level, int *modified);
static List *
fireRules(Query *parsetree, int rt_index, CmdType event,
static List *fireRules(Query *parsetree, int rt_index, CmdType event,
bool *instead_flag, List *locks, List **qual_products);
static void QueryRewriteSubLink(Node *node);
static List *QueryRewriteOne(Query *parsetree);
static List *deepRewriteQuery(Query *parsetree);
/*
@ -77,11 +77,11 @@ gatherRewriteMeta(Query *parsetree,
OffsetVarNodes((Node *) info->rule_action->targetList, rt_length);
OffsetVarNodes(info->rule_qual, rt_length);
ChangeVarNodes((Node *) info->rule_action->qual,
PRS2_CURRENT_VARNO + rt_length, rt_index);
PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
ChangeVarNodes((Node *) info->rule_action->targetList,
PRS2_CURRENT_VARNO + rt_length, rt_index);
PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
ChangeVarNodes(info->rule_qual,
PRS2_CURRENT_VARNO + rt_length, rt_index);
PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
/*
* bug here about replace CURRENT -- sort of replace current is
@ -292,10 +292,10 @@ ApplyRetrieveRule(Query *parsetree,
OffsetVarNodes((Node *) rule_action->targetList, rt_length);
OffsetVarNodes(rule_qual, rt_length);
ChangeVarNodes(rule_action->qual,
PRS2_CURRENT_VARNO + rt_length, rt_index);
PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
ChangeVarNodes((Node *) rule_action->targetList,
PRS2_CURRENT_VARNO + rt_length, rt_index);
ChangeVarNodes(rule_qual, PRS2_CURRENT_VARNO + rt_length, rt_index);
PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
ChangeVarNodes(rule_qual, PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
if (relation_level)
{
HandleViewRule(parsetree, rtable, rule_action->targetList, rt_index,
@ -402,7 +402,7 @@ CopyAndAddQual(Query *parsetree,
rtable = append(rtable, listCopy(rule_action->rtable));
new_tree->rtable = rtable;
OffsetVarNodes(new_qual, rt_length);
ChangeVarNodes(new_qual, PRS2_CURRENT_VARNO + rt_length, rt_index);
ChangeVarNodes(new_qual, PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
}
/* XXX -- where current doesn't work for instead nothing.... yet */
AddNotQual(new_tree, new_qual);
@ -627,6 +627,82 @@ static int numQueryRewriteInvoked = 0;
*/
List *
QueryRewrite(Query *parsetree)
{
QueryRewriteSubLink(parsetree->qual);
return QueryRewriteOne(parsetree);
}
/*
* QueryRewriteSubLink
*
* This rewrites the SubLink subqueries first, doing the lowest ones first.
* We already have code in the main rewrite loops to process correlated
* variables from upper queries that exist in subqueries.
*/
static void
QueryRewriteSubLink(Node *node)
{
if (node == NULL)
return;
switch (nodeTag(node))
{
case T_TargetEntry:
break;
case T_Aggreg:
break;
case T_Expr:
{
Expr *expr = (Expr *) node;
QueryRewriteSubLink((Node *)expr->args);
}
break;
case T_Var:
break;
case T_List:
{
List *l;
foreach(l, (List *) node)
QueryRewriteSubLink(lfirst(l));
}
break;
case T_SubLink:
{
SubLink *sublink = (SubLink *) node;
Query *query = (Query *)sublink->subselect;
List *ret;
/*
* Nest down first. We do this so if a rewrite adds a
* SubLink we don't process it as part of this loop.
*/
QueryRewriteSubLink((Node *)query->qual);
ret = QueryRewriteOne(query);
if (!ret)
sublink->subselect = NULL;
else if (lnext(ret) == NIL)
sublink->subselect = lfirst(ret);
else
elog(ERROR,"Don't know how to process subquery that rewrites to multiple queries.");
}
break;
default:
/* ignore the others */
break;
}
return;
}
/*
* QueryOneRewrite -
* rewrite one query
*/
static List *
QueryRewriteOne(Query *parsetree)
{
numQueryRewriteInvoked = 0;