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Commite64a331

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committed
Fix some (more) problems with subselects in rules. Rewriter failed to
mark query as having subselects if a subselect was added from a ruleWHERE condition (as opposed to a rule action). Also, fix adjustmentof varlevelsup so that it actually has some prospect of working wheninserting an expression containing a subselect into a subquery.
1 parent4a3a1e2 commite64a331

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3 files changed

+188
-166
lines changed

3 files changed

+188
-166
lines changed

‎src/backend/rewrite/rewriteHandler.c

Lines changed: 22 additions & 146 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.68 2000/03/12 18:57:05 tgl Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.69 2000/03/16 03:23:18 tgl Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -55,16 +55,11 @@ static RewriteInfo *gatherRewriteMeta(Query *parsetree,
5555
staticboolrangeTableEntry_used(Node*node,intrt_index,intsublevels_up);
5656
staticboolattribute_used(Node*node,intrt_index,intattno,
5757
intsublevels_up);
58-
staticboolmodifyAggrefUplevel(Node*node,void*context);
5958
staticboolmodifyAggrefChangeVarnodes(Node*node,intrt_index,intnew_index,
6059
intsublevels_up,intnew_sublevels_up);
6160
staticNode*modifyAggrefDropQual(Node*node,Node*targetNode);
6261
staticSubLink*modifyAggrefMakeSublink(Aggref*aggref,Query*parsetree);
6362
staticNode*modifyAggrefQual(Node*node,Query*parsetree);
64-
staticboolcheckQueryHasAggs(Node*node);
65-
staticboolcheckQueryHasAggs_walker(Node*node,void*context);
66-
staticboolcheckQueryHasSubLink(Node*node);
67-
staticboolcheckQueryHasSubLink_walker(Node*node,void*context);
6863
staticQuery*fireRIRrules(Query*parsetree);
6964
staticQuery*Except_Intersect_Rewrite(Query*parsetree);
7065
staticvoidcheck_targetlists_are_compatible(List*prev_target,
@@ -290,65 +285,15 @@ attribute_used(Node *node, int rt_index, int attno, int sublevels_up)
290285
}
291286

292287

293-
/*
294-
* modifyAggrefUplevel -
295-
*In the newly created sublink for an aggregate column used in
296-
*the qualification, we must increment the varlevelsup in all the
297-
*var nodes.
298-
*
299-
* NOTE: although this has the form of a walker, we cheat and modify the
300-
* Var nodes in-place. The given expression tree should have been copied
301-
* earlier to ensure that no unwanted side-effects occur!
302-
*/
303-
staticbool
304-
modifyAggrefUplevel(Node*node,void*context)
305-
{
306-
if (node==NULL)
307-
return false;
308-
if (IsA(node,Var))
309-
{
310-
Var*var= (Var*)node;
311-
312-
var->varlevelsup++;
313-
return false;
314-
}
315-
if (IsA(node,SubLink))
316-
{
317-
/*
318-
* Standard expression_tree_walker will not recurse into subselect,
319-
* but here we must do so.
320-
*/
321-
SubLink*sub= (SubLink*)node;
322-
323-
if (modifyAggrefUplevel((Node*) (sub->lefthand),context))
324-
return true;
325-
if (modifyAggrefUplevel((Node*) (sub->subselect),context))
326-
return true;
327-
return false;
328-
}
329-
if (IsA(node,Query))
330-
{
331-
/* Reach here after recursing down into subselect above... */
332-
Query*qry= (Query*)node;
333-
334-
if (modifyAggrefUplevel((Node*) (qry->targetList),context))
335-
return true;
336-
if (modifyAggrefUplevel((Node*) (qry->qual),context))
337-
return true;
338-
if (modifyAggrefUplevel((Node*) (qry->havingQual),context))
339-
return true;
340-
return false;
341-
}
342-
returnexpression_tree_walker(node,modifyAggrefUplevel,
343-
(void*)context);
344-
}
345-
346-
347288
/*
348289
* modifyAggrefChangeVarnodes -
349290
*Change the var nodes in a sublink created for an aggregate column
350291
*used in the qualification to point to the correct local RTE.
351292
*
293+
* XXX if we still need this after redoing querytree design, it should
294+
* be combined with ChangeVarNodes, which is the same thing except for
295+
* not having the option to adjust the vars' varlevelsup.
296+
*
352297
* NOTE: although this has the form of a walker, we cheat and modify the
353298
* Var nodes in-place. The given expression tree should have been copied
354299
* earlier to ensure that no unwanted side-effects occur!
@@ -547,18 +492,18 @@ modifyAggrefMakeSublink(Aggref *aggref, Query *parsetree)
547492
* Recursing would be a bad idea --- we'd likely produce an
548493
* infinite recursion. This whole technique is a crock, really...
549494
*/
550-
if (checkQueryHasAggs(subquery->qual))
495+
if (checkExprHasAggs(subquery->qual))
551496
elog(ERROR,"Cannot handle multiple aggregate functions in WHERE clause");
552497
subquery->groupClause=NIL;
553498
subquery->havingQual=NULL;
554499
subquery->hasAggs= TRUE;
555-
subquery->hasSubLinks=checkQueryHasSubLink(subquery->qual);
500+
subquery->hasSubLinks=checkExprHasSubLink(subquery->qual);
556501
subquery->unionClause=NULL;
557502

558503
/* Increment all varlevelsup fields in the new subquery */
559-
modifyAggrefUplevel((Node*)subquery,NULL);
504+
IncrementVarSublevelsUp((Node*)subquery,1,0);
560505

561-
/* Replace references to the target table with correct varno.
506+
/* Replace references to the target table with correctlocalvarno.
562507
* Note +1 here to account for effects of previous line!
563508
*/
564509
modifyAggrefChangeVarnodes((Node*)subquery,target->varno,
@@ -600,49 +545,6 @@ modifyAggrefQual(Node *node, Query *parsetree)
600545
}
601546

602547

603-
/*
604-
* checkQueryHasAggs -
605-
*Queries marked hasAggs might not have them any longer after
606-
*rewriting. Check it.
607-
*/
608-
staticbool
609-
checkQueryHasAggs(Node*node)
610-
{
611-
returncheckQueryHasAggs_walker(node,NULL);
612-
}
613-
614-
staticbool
615-
checkQueryHasAggs_walker(Node*node,void*context)
616-
{
617-
if (node==NULL)
618-
return false;
619-
if (IsA(node,Aggref))
620-
return true;/* abort the tree traversal and return true */
621-
returnexpression_tree_walker(node,checkQueryHasAggs_walker,context);
622-
}
623-
624-
/*
625-
* checkQueryHasSubLink -
626-
*Queries marked hasSubLinks might not have them any longer after
627-
*rewriting. Check it.
628-
*/
629-
staticbool
630-
checkQueryHasSubLink(Node*node)
631-
{
632-
returncheckQueryHasSubLink_walker(node,NULL);
633-
}
634-
635-
staticbool
636-
checkQueryHasSubLink_walker(Node*node,void*context)
637-
{
638-
if (node==NULL)
639-
return false;
640-
if (IsA(node,SubLink))
641-
return true;/* abort the tree traversal and return true */
642-
returnexpression_tree_walker(node,checkQueryHasSubLink_walker,context);
643-
}
644-
645-
646548
staticNode*
647549
FindMatchingTLEntry(List*tlist,char*e_attname)
648550
{
@@ -675,38 +577,6 @@ make_null(Oid type)
675577
}
676578

677579

678-
/*
679-
* apply_RIR_adjust_sublevel -
680-
*Set the varlevelsup field of all Var nodes in the given expression tree
681-
*to sublevels_up. We do NOT recurse into subselects.
682-
*
683-
* NOTE: although this has the form of a walker, we cheat and modify the
684-
* Var nodes in-place. The given expression tree should have been copied
685-
* earlier to ensure that no unwanted side-effects occur!
686-
*/
687-
staticbool
688-
apply_RIR_adjust_sublevel_walker(Node*node,int*sublevels_up)
689-
{
690-
if (node==NULL)
691-
return false;
692-
if (IsA(node,Var))
693-
{
694-
Var*var= (Var*)node;
695-
696-
var->varlevelsup=*sublevels_up;
697-
return false;
698-
}
699-
returnexpression_tree_walker(node,apply_RIR_adjust_sublevel_walker,
700-
(void*)sublevels_up);
701-
}
702-
703-
staticvoid
704-
apply_RIR_adjust_sublevel(Node*node,intsublevels_up)
705-
{
706-
apply_RIR_adjust_sublevel_walker(node,&sublevels_up);
707-
}
708-
709-
710580
/*
711581
* apply_RIR_view
712582
*Replace Vars matching a given RT index with copies of TL expressions.
@@ -749,9 +619,12 @@ apply_RIR_view_mutator(Node *node,
749619
returnmake_null(var->vartype);
750620
}
751621

622+
/* Make a copy of the tlist item to return */
752623
expr=copyObject(expr);
624+
/* Adjust varlevelsup if tlist item is from higher query level */
753625
if (var->varlevelsup>0)
754-
apply_RIR_adjust_sublevel(expr,var->varlevelsup);
626+
IncrementVarSublevelsUp(expr,var->varlevelsup,0);
627+
755628
*(context->modified)= true;
756629
return (Node*)expr;
757630
}
@@ -1279,8 +1152,11 @@ fireRules(Query *parsetree,
12791152
else
12801153
qual_product= (Query*)nth(0,*qual_products);
12811154

1155+
MemSet(&qual_info,0,sizeof(qual_info));
12821156
qual_info.event=qual_product->commandType;
1157+
qual_info.current_varno=rt_index;
12831158
qual_info.new_varno=length(qual_product->rtable)+2;
1159+
12841160
qual_product=CopyAndAddQual(qual_product,
12851161
actions,
12861162
event_qual,
@@ -1575,16 +1451,16 @@ BasicQueryRewrite(Query *parsetree)
15751451
if (query->hasAggs)
15761452
{
15771453
query->hasAggs=
1578-
checkQueryHasAggs((Node*) (query->targetList))||
1579-
checkQueryHasAggs((Node*) (query->havingQual));
1580-
if (checkQueryHasAggs((Node*) (query->qual)))
1454+
checkExprHasAggs((Node*) (query->targetList))||
1455+
checkExprHasAggs((Node*) (query->havingQual));
1456+
if (checkExprHasAggs((Node*) (query->qual)))
15811457
elog(ERROR,"BasicQueryRewrite: failed to remove aggs from qual");
15821458
}
15831459
if (query->hasSubLinks)
15841460
query->hasSubLinks=
1585-
checkQueryHasSubLink((Node*) (query->targetList))||
1586-
checkQueryHasSubLink((Node*) (query->qual))||
1587-
checkQueryHasSubLink((Node*) (query->havingQual));
1461+
checkExprHasSubLink((Node*) (query->targetList))||
1462+
checkExprHasSubLink((Node*) (query->qual))||
1463+
checkExprHasSubLink((Node*) (query->havingQual));
15881464
results=lappend(results,query);
15891465
}
15901466

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