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Revise implementation of SubLinks so that there is a consistent,

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documented intepretation of the lefthand and oper fields.  Fix a number of
obscure problems while at it --- for example, the old code failed if the parser
decided to insert a type-coercion function just below the operator of a
SubLink.
CAUTION: this will break stored rules that contain subplans.  You may
need to initdb.
This commit is contained in:
Tom Lane
1999-08-25 23:21:43 +00:00
parent edda70c0de
commit 42af56e1ea
8 changed files with 326 additions and 322 deletions
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79
src/backend/rewrite/rewriteHandler.c
View File

@@ -6,19 +6,23 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.54 1999/07/17 20:17:37 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.55 1999/08/25 23:21:43 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/heapam.h"
#include "catalog/pg_operator.h"
#include "catalog/pg_type.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/prep.h"
#include "parser/analyze.h"
#include "parser/parse_expr.h"
#include "parser/parse_relation.h"
#include "parser/parse_oper.h"
#include "parser/parse_target.h"
#include "parser/parse_type.h"
#include "parser/parsetree.h"
@@ -642,9 +646,6 @@ modifyAggrefUplevel(Node *node)
modifyAggrefUplevel(
(Node *) (sub->lefthand));
modifyAggrefUplevel(
(Node *) (sub->oper));
modifyAggrefUplevel(
(Node *) (sub->subselect));
}
@@ -816,12 +817,6 @@ modifyAggrefChangeVarnodes(Node **nodePtr, int rt_index, int new_index, int subl
new_index,
sublevels_up);
modifyAggrefChangeVarnodes(
(Node **) (&(sub->oper)),
rt_index,
new_index,
sublevels_up);
modifyAggrefChangeVarnodes(
(Node **) (&(sub->subselect)),
rt_index,
@@ -989,6 +984,7 @@ modifyAggrefDropQual(Node **nodePtr, Node *orignode, Expr *expr)
SubLink *sub = (SubLink *) node;
SubLink *osub = (SubLink *) orignode;
/* what about the lefthand? */
modifyAggrefDropQual(
(Node **) (&(sub->subselect)),
(Node *) (osub->subselect),
@@ -1046,19 +1042,21 @@ modifyAggrefMakeSublink(Expr *origexp, Query *parsetree)
if (nodeTag(nth(1, exp->args)) == T_Aggref)
elog(ERROR, "rewrite: comparision of 2 aggregate columns not supported");
else
elog(ERROR, "rewrite: aggregate column of view must be at rigth side in qual");
elog(ERROR, "rewrite: aggregate column of view must be at right side in qual");
}
aggref = (Aggref *) nth(1, exp->args);
target = (Var *) (aggref->target);
/* XXX bogus --- agg's target might not be a Var! */
rte = (RangeTblEntry *) nth(target->varno - 1, parsetree->rtable);
tle = makeNode(TargetEntry);
resdom = makeNode(Resdom);
aggref->usenulls = TRUE;
aggref->usenulls = TRUE; /* XXX safe for all aggs?? */
resdom->resno = 1;
resdom->restype = ((Oper *) (exp->oper))->opresulttype;
resdom->restype = aggref->aggtype;
resdom->restypmod = -1;
resdom->resname = pstrdup("<noname>");
resdom->reskey = 0;
@@ -1074,9 +1072,8 @@ modifyAggrefMakeSublink(Expr *origexp, Query *parsetree)
sublink = makeNode(SubLink);
sublink->subLinkType = EXPR_SUBLINK;
sublink->useor = FALSE;
sublink->lefthand = lappend(NIL, copyObject(lfirst(exp->args)));
sublink->oper = lappend(NIL, copyObject(exp));
sublink->subselect = NULL;
sublink->lefthand = lcons(lfirst(exp->args), NIL);
sublink->oper = lcons(exp->oper, NIL);
subquery = makeNode(Query);
sublink->subselect = (Node *) subquery;
@@ -1105,8 +1102,6 @@ modifyAggrefMakeSublink(Expr *origexp, Query *parsetree)
modifyAggrefChangeVarnodes((Node **) &(sublink->lefthand), target->varno,
1, target->varlevelsup);
modifyAggrefChangeVarnodes((Node **) &(sublink->oper), target->varno,
1, target->varlevelsup);
modifyAggrefChangeVarnodes((Node **) &(sublink->subselect), target->varno,
1, target->varlevelsup);
@@ -1249,6 +1244,7 @@ modifyAggrefQual(Node **nodePtr, Query *parsetree)
{
SubLink *sub = (SubLink *) node;
/* lefthand ??? */
modifyAggrefQual(
(Node **) (&(sub->subselect)),
(Query *) (sub->subselect));
@@ -1318,9 +1314,6 @@ checkQueryHasSubLink_walker(Node *node, void *context)
return false;
if (IsA(node, SubLink))
return true; /* abort the tree traversal and return true */
/* Note: we assume the tree has not yet been rewritten by subselect.c,
* therefore we will find bare SubLink nodes and not SUBPLAN nodes.
*/
return expression_tree_walker(node, checkQueryHasSubLink_walker, context);
}
@@ -1654,8 +1647,6 @@ apply_RIR_view(Node **nodePtr, int rt_index, RangeTblEntry *rte, List *tlist, in
case T_SubLink:
{
SubLink *sub = (SubLink *) node;
List *tmp_lefthand,
*tmp_oper;
apply_RIR_view(
(Node **) (&(sub->lefthand)),
@@ -1672,14 +1663,6 @@ apply_RIR_view(Node **nodePtr, int rt_index, RangeTblEntry *rte, List *tlist, in
tlist,
modified,
sublevels_up + 1);
tmp_lefthand = sub->lefthand;
foreach(tmp_oper, sub->oper)
{
lfirst(((Expr *) lfirst(tmp_oper))->args) =
lfirst(tmp_lefthand);
tmp_lefthand = lnext(tmp_lefthand);
}
}
break;
@@ -3014,31 +2997,47 @@ Except_Intersect_Rewrite(Query *parsetree)
* of the targetlist must be (IN) or must not be (NOT IN) the
* subselect
*/
n->lefthand = NIL;
foreach(elist, intersect_node->targetList)
{
Node *expr = lfirst(elist);
TargetEntry *tent = (TargetEntry *) expr;
TargetEntry *tent = (TargetEntry *) lfirst(elist);
n->lefthand = lappend(n->lefthand, tent->expr);
}
/*
* The first arguments of oper also have to be created for the
* sublink (they are the same as the lefthand side!)
* Also prepare the list of Opers that must be used for the
* comparisons (they depend on the specific datatypes involved!)
*/
left_expr = n->lefthand;
right_expr = ((Query *) (n->subselect))->targetList;
n->oper = NIL;
foreach(elist, left_expr)
{
Node *lexpr = lfirst(elist);
Node *rexpr = lfirst(right_expr);
TargetEntry *tent = (TargetEntry *) rexpr;
Expr *op_expr;
TargetEntry *tent = (TargetEntry *) lfirst(right_expr);
Operator optup;
Form_pg_operator opform;
Oper *newop;
op_expr = make_op(op, lexpr, tent->expr);
optup = oper(op,
exprType(lexpr),
exprType(tent->expr),
FALSE);
opform = (Form_pg_operator) GETSTRUCT(optup);
if (opform->oprresult != BOOLOID)
elog(ERROR, "parser: '%s' must return 'bool' to be used with quantified predicate subquery", op);
newop = makeOper(oprid(optup),/* opno */
InvalidOid, /* opid */
opform->oprresult,
0,
NULL);
n->oper = lappend(n->oper, newop);
n->oper = lappend(n->oper, op_expr);
right_expr = lnext(right_expr);
}