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Revise implementation of SubLinks so that there is a consistent,
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
@ -6,19 +6,23 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.54 1999/07/17 20:17:37 momjian Exp $
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* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.55 1999/08/25 23:21:43 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "access/heapam.h"
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#include "catalog/pg_operator.h"
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#include "catalog/pg_type.h"
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#include "miscadmin.h"
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#include "nodes/makefuncs.h"
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#include "optimizer/clauses.h"
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#include "optimizer/prep.h"
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#include "parser/analyze.h"
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#include "parser/parse_expr.h"
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#include "parser/parse_relation.h"
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#include "parser/parse_oper.h"
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#include "parser/parse_target.h"
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#include "parser/parse_type.h"
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#include "parser/parsetree.h"
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@ -642,9 +646,6 @@ modifyAggrefUplevel(Node *node)
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modifyAggrefUplevel(
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(Node *) (sub->lefthand));
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modifyAggrefUplevel(
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(Node *) (sub->oper));
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modifyAggrefUplevel(
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(Node *) (sub->subselect));
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}
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@ -816,12 +817,6 @@ modifyAggrefChangeVarnodes(Node **nodePtr, int rt_index, int new_index, int subl
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new_index,
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sublevels_up);
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modifyAggrefChangeVarnodes(
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(Node **) (&(sub->oper)),
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rt_index,
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new_index,
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sublevels_up);
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modifyAggrefChangeVarnodes(
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(Node **) (&(sub->subselect)),
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rt_index,
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@ -989,6 +984,7 @@ modifyAggrefDropQual(Node **nodePtr, Node *orignode, Expr *expr)
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SubLink *sub = (SubLink *) node;
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SubLink *osub = (SubLink *) orignode;
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/* what about the lefthand? */
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modifyAggrefDropQual(
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(Node **) (&(sub->subselect)),
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(Node *) (osub->subselect),
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@ -1046,19 +1042,21 @@ modifyAggrefMakeSublink(Expr *origexp, Query *parsetree)
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if (nodeTag(nth(1, exp->args)) == T_Aggref)
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elog(ERROR, "rewrite: comparision of 2 aggregate columns not supported");
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else
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elog(ERROR, "rewrite: aggregate column of view must be at rigth side in qual");
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elog(ERROR, "rewrite: aggregate column of view must be at right side in qual");
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}
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aggref = (Aggref *) nth(1, exp->args);
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target = (Var *) (aggref->target);
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/* XXX bogus --- agg's target might not be a Var! */
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rte = (RangeTblEntry *) nth(target->varno - 1, parsetree->rtable);
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tle = makeNode(TargetEntry);
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resdom = makeNode(Resdom);
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aggref->usenulls = TRUE;
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aggref->usenulls = TRUE; /* XXX safe for all aggs?? */
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resdom->resno = 1;
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resdom->restype = ((Oper *) (exp->oper))->opresulttype;
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resdom->restype = aggref->aggtype;
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resdom->restypmod = -1;
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resdom->resname = pstrdup("<noname>");
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resdom->reskey = 0;
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@ -1074,9 +1072,8 @@ modifyAggrefMakeSublink(Expr *origexp, Query *parsetree)
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sublink = makeNode(SubLink);
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sublink->subLinkType = EXPR_SUBLINK;
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sublink->useor = FALSE;
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sublink->lefthand = lappend(NIL, copyObject(lfirst(exp->args)));
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sublink->oper = lappend(NIL, copyObject(exp));
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sublink->subselect = NULL;
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sublink->lefthand = lcons(lfirst(exp->args), NIL);
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sublink->oper = lcons(exp->oper, NIL);
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subquery = makeNode(Query);
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sublink->subselect = (Node *) subquery;
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@ -1105,8 +1102,6 @@ modifyAggrefMakeSublink(Expr *origexp, Query *parsetree)
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modifyAggrefChangeVarnodes((Node **) &(sublink->lefthand), target->varno,
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1, target->varlevelsup);
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modifyAggrefChangeVarnodes((Node **) &(sublink->oper), target->varno,
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1, target->varlevelsup);
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modifyAggrefChangeVarnodes((Node **) &(sublink->subselect), target->varno,
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1, target->varlevelsup);
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@ -1249,6 +1244,7 @@ modifyAggrefQual(Node **nodePtr, Query *parsetree)
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{
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SubLink *sub = (SubLink *) node;
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/* lefthand ??? */
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modifyAggrefQual(
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(Node **) (&(sub->subselect)),
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(Query *) (sub->subselect));
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@ -1318,9 +1314,6 @@ checkQueryHasSubLink_walker(Node *node, void *context)
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return false;
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if (IsA(node, SubLink))
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return true; /* abort the tree traversal and return true */
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/* Note: we assume the tree has not yet been rewritten by subselect.c,
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* therefore we will find bare SubLink nodes and not SUBPLAN nodes.
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*/
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return expression_tree_walker(node, checkQueryHasSubLink_walker, context);
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}
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@ -1654,8 +1647,6 @@ apply_RIR_view(Node **nodePtr, int rt_index, RangeTblEntry *rte, List *tlist, in
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case T_SubLink:
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{
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SubLink *sub = (SubLink *) node;
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List *tmp_lefthand,
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*tmp_oper;
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apply_RIR_view(
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(Node **) (&(sub->lefthand)),
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@ -1672,14 +1663,6 @@ apply_RIR_view(Node **nodePtr, int rt_index, RangeTblEntry *rte, List *tlist, in
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tlist,
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modified,
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sublevels_up + 1);
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tmp_lefthand = sub->lefthand;
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foreach(tmp_oper, sub->oper)
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{
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lfirst(((Expr *) lfirst(tmp_oper))->args) =
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lfirst(tmp_lefthand);
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tmp_lefthand = lnext(tmp_lefthand);
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}
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}
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break;
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@ -3014,31 +2997,47 @@ Except_Intersect_Rewrite(Query *parsetree)
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* of the targetlist must be (IN) or must not be (NOT IN) the
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* subselect
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*/
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n->lefthand = NIL;
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foreach(elist, intersect_node->targetList)
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{
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Node *expr = lfirst(elist);
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TargetEntry *tent = (TargetEntry *) expr;
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TargetEntry *tent = (TargetEntry *) lfirst(elist);
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n->lefthand = lappend(n->lefthand, tent->expr);
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}
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/*
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* The first arguments of oper also have to be created for the
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* sublink (they are the same as the lefthand side!)
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* Also prepare the list of Opers that must be used for the
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* comparisons (they depend on the specific datatypes involved!)
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*/
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left_expr = n->lefthand;
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right_expr = ((Query *) (n->subselect))->targetList;
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n->oper = NIL;
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foreach(elist, left_expr)
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{
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Node *lexpr = lfirst(elist);
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Node *rexpr = lfirst(right_expr);
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TargetEntry *tent = (TargetEntry *) rexpr;
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Expr *op_expr;
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TargetEntry *tent = (TargetEntry *) lfirst(right_expr);
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Operator optup;
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Form_pg_operator opform;
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Oper *newop;
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op_expr = make_op(op, lexpr, tent->expr);
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optup = oper(op,
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exprType(lexpr),
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exprType(tent->expr),
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FALSE);
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opform = (Form_pg_operator) GETSTRUCT(optup);
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if (opform->oprresult != BOOLOID)
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elog(ERROR, "parser: '%s' must return 'bool' to be used with quantified predicate subquery", op);
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newop = makeOper(oprid(optup),/* opno */
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InvalidOid, /* opid */
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opform->oprresult,
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0,
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NULL);
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n->oper = lappend(n->oper, newop);
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n->oper = lappend(n->oper, op_expr);
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right_expr = lnext(right_expr);
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}
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@ -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/rewriteManip.c,v 1.39 1999/08/21 03:49:13 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteManip.c,v 1.40 1999/08/25 23:21:43 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -137,13 +137,7 @@ OffsetVarNodes(Node *node, int offset, int sublevels_up)
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case T_SubLink:
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{
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SubLink *sub = (SubLink *) node;
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List *tmp_oper,
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*tmp_lefthand;
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/*
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* We also have to adapt the variables used in
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* sub->lefthand and sub->oper
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*/
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OffsetVarNodes(
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(Node *) (sub->lefthand),
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offset,
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@ -153,20 +147,6 @@ OffsetVarNodes(Node *node, int offset, int sublevels_up)
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(Node *) (sub->subselect),
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offset,
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sublevels_up + 1);
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/*
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* Make sure the first argument of sub->oper points to the
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* same var as sub->lefthand does otherwise we will run
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* into troubles using aggregates (aggno will not be set
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* correctly)
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*/
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tmp_lefthand = sub->lefthand;
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foreach(tmp_oper, sub->oper)
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{
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lfirst(((Expr *) lfirst(tmp_oper))->args) =
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lfirst(tmp_lefthand);
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tmp_lefthand = lnext(tmp_lefthand);
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}
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}
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break;
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@ -357,8 +337,6 @@ ChangeVarNodes(Node *node, int rt_index, int new_index, int sublevels_up)
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case T_SubLink:
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{
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SubLink *sub = (SubLink *) node;
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List *tmp_oper,
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*tmp_lefthand;
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ChangeVarNodes(
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(Node *) (sub->lefthand),
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@ -371,20 +349,6 @@ ChangeVarNodes(Node *node, int rt_index, int new_index, int sublevels_up)
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rt_index,
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new_index,
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sublevels_up + 1);
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/*
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* Make sure the first argument of sub->oper points to the
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* same var as sub->lefthand does otherwise we will run
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* into troubles using aggregates (aggno will not be set
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* correctly)
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*/
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tmp_lefthand = sub->lefthand;
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foreach(tmp_oper, sub->oper)
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{
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lfirst(((Expr *) lfirst(tmp_oper))->args) =
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lfirst(tmp_lefthand);
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tmp_lefthand = lnext(tmp_lefthand);
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}
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}
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break;
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@ -732,6 +696,7 @@ ResolveNew(RewriteInfo *info, List *targetlist, Node **nodePtr,
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SubLink *sublink = (SubLink *) node;
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Query *query = (Query *) sublink->subselect;
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/* XXX what about lefthand? What about rest of subquery? */
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ResolveNew(info, targetlist, (Node **) &(query->qual), sublevels_up + 1);
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}
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break;
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@ -888,6 +853,7 @@ nodeHandleRIRAttributeRule(Node **nodePtr,
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SubLink *sublink = (SubLink *) node;
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Query *query = (Query *) sublink->subselect;
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/* XXX what about lefthand? What about rest of subquery? */
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nodeHandleRIRAttributeRule((Node **) &(query->qual), rtable, targetlist,
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rt_index, attr_num, modified, badsql,
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sublevels_up + 1);
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@ -1062,9 +1028,6 @@ nodeHandleViewRule(Node **nodePtr,
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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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List *tmp_lefthand,
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*tmp_oper;
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nodeHandleViewRule((Node **) &(query->qual), rtable, targetlist,
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rt_index, modified, sublevels_up + 1);
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@ -1078,30 +1041,10 @@ nodeHandleViewRule(Node **nodePtr,
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/*
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* We also have to adapt the variables used in
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* sublink->lefthand and sublink->oper
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* sublink->lefthand
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*/
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nodeHandleViewRule((Node **) &(sublink->lefthand), rtable,
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targetlist, rt_index, modified, sublevels_up);
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/*
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* Make sure the first argument of sublink->oper points to
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* the same var as sublink->lefthand does otherwise we
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* will run into troubles using aggregates (aggno will not
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* be set correctly
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*/
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pfree(lfirst(((Expr *) lfirst(sublink->oper))->args));
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lfirst(((Expr *) lfirst(sublink->oper))->args) =
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lfirst(sublink->lefthand);
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/* INTERSECT want's this - Jan */
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/*
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* tmp_lefthand = sublink->lefthand; foreach(tmp_oper,
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* sublink->oper) { lfirst(((Expr *)
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* lfirst(tmp_oper))->args) = lfirst(tmp_lefthand);
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* tmp_lefthand = lnext(tmp_lefthand); }
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*/
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}
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break;
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default:
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