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Commita44174c

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Fix subselect.c to avoid assuming that a SubLink's testexpr references each
subquery output column exactly once left-to-right. Although this is the casein the original parser output, it might not be so after rewriting andconstant-folding, as illustrated by bug #3882 from Jan Mate. Insteadscan the subquery's target list to obtain needed per-column information;this is duplicative of what the parser did, but only a couple dozen linesneed be copied, and we can clean up a couple of notational uglinesses.Bug was introduced in 8.2 as part of revision of SubLink representation.
1 parent0df7717 commita44174c

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1 file changed

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‎src/backend/optimizer/plan/subselect.c

Lines changed: 107 additions & 70 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1994, Regents of the University of California
88
*
99
* IDENTIFICATION
10-
* $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.128 2008/01/01 19:45:50 momjian Exp $
10+
* $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.129 2008/01/17 20:35:27 tgl Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -35,8 +35,7 @@
3535
typedefstructconvert_testexpr_context
3636
{
3737
PlannerInfo*root;
38-
intrtindex;/* RT index for Vars, or 0 for Params */
39-
List*righthandIds;/* accumulated list of Vars or Param IDs */
38+
List*subst_nodes;/* Nodes to substitute for Params */
4039
}convert_testexpr_context;
4140

4241
typedefstructprocess_sublinks_context
@@ -53,10 +52,13 @@ typedef struct finalize_primnode_context
5352
}finalize_primnode_context;
5453

5554

55+
staticList*generate_subquery_params(PlannerInfo*root,List*tlist,
56+
List**paramIds);
57+
staticList*generate_subquery_vars(PlannerInfo*root,List*tlist,
58+
Indexvarno);
5659
staticNode*convert_testexpr(PlannerInfo*root,
5760
Node*testexpr,
58-
intrtindex,
59-
List**righthandIds);
61+
List*subst_nodes);
6062
staticNode*convert_testexpr_mutator(Node*node,
6163
convert_testexpr_context*context);
6264
staticboolsubplan_is_hashable(SubLink*slink,SubPlan*node,Plan*plan);
@@ -374,10 +376,14 @@ make_subplan(PlannerInfo *root, SubLink *slink, Node *testexpr, bool isTopQual)
374376
elseif (splan->parParam==NIL&&slink->subLinkType==ROWCOMPARE_SUBLINK)
375377
{
376378
/* Adjust the Params */
379+
List*params;
380+
381+
params=generate_subquery_params(root,
382+
plan->targetlist,
383+
&splan->paramIds);
377384
result=convert_testexpr(root,
378385
testexpr,
379-
0,
380-
&splan->paramIds);
386+
params);
381387
splan->setParam=list_copy(splan->paramIds);
382388
isInitPlan= true;
383389

@@ -388,14 +394,17 @@ make_subplan(PlannerInfo *root, SubLink *slink, Node *testexpr, bool isTopQual)
388394
}
389395
else
390396
{
397+
List*params;
391398
List*args;
392399
ListCell*l;
393400

394401
/* Adjust the Params */
402+
params=generate_subquery_params(root,
403+
plan->targetlist,
404+
&splan->paramIds);
395405
splan->testexpr=convert_testexpr(root,
396406
testexpr,
397-
0,
398-
&splan->paramIds);
407+
params);
399408

400409
/*
401410
* We can't convert subplans of ALL_SUBLINK or ANY_SUBLINK types to
@@ -482,17 +491,76 @@ make_subplan(PlannerInfo *root, SubLink *slink, Node *testexpr, bool isTopQual)
482491
returnresult;
483492
}
484493

494+
/*
495+
* generate_subquery_params: build a list of Params representing the output
496+
* columns of a sublink's sub-select, given the sub-select's targetlist.
497+
*
498+
* We also return an integer list of the paramids of the Params.
499+
*/
500+
staticList*
501+
generate_subquery_params(PlannerInfo*root,List*tlist,List**paramIds)
502+
{
503+
List*result;
504+
List*ids;
505+
ListCell*lc;
506+
507+
result=ids=NIL;
508+
foreach(lc,tlist)
509+
{
510+
TargetEntry*tent= (TargetEntry*)lfirst(lc);
511+
Param*param;
512+
513+
if (tent->resjunk)
514+
continue;
515+
516+
param=generate_new_param(root,
517+
exprType((Node*)tent->expr),
518+
exprTypmod((Node*)tent->expr));
519+
result=lappend(result,param);
520+
ids=lappend_int(ids,param->paramid);
521+
}
522+
523+
*paramIds=ids;
524+
returnresult;
525+
}
526+
527+
/*
528+
* generate_subquery_vars: build a list of Vars representing the output
529+
* columns of a sublink's sub-select, given the sub-select's targetlist.
530+
* The Vars have the specified varno (RTE index).
531+
*/
532+
staticList*
533+
generate_subquery_vars(PlannerInfo*root,List*tlist,Indexvarno)
534+
{
535+
List*result;
536+
ListCell*lc;
537+
538+
result=NIL;
539+
foreach(lc,tlist)
540+
{
541+
TargetEntry*tent= (TargetEntry*)lfirst(lc);
542+
Var*var;
543+
544+
if (tent->resjunk)
545+
continue;
546+
547+
var=makeVar(varno,
548+
tent->resno,
549+
exprType((Node*)tent->expr),
550+
exprTypmod((Node*)tent->expr),
551+
0);
552+
result=lappend(result,var);
553+
}
554+
555+
returnresult;
556+
}
557+
485558
/*
486559
* convert_testexpr: convert the testexpr given by the parser into
487560
* actually executable form. This entails replacing PARAM_SUBLINK Params
488-
* with Params or Vars representing the results of the sub-select:
489-
*
490-
* If rtindex is 0, we build Params to represent the sub-select outputs.
491-
* The paramids of the Params created are returned in the *righthandIds list.
492-
*
493-
* If rtindex is not 0, we build Vars using that rtindex as varno.Copies
494-
* of the Var nodes are returned in *righthandIds (this is a bit of a type
495-
* cheat, but we can get away with it).
561+
* with Params or Vars representing the results of the sub-select. The
562+
* nodes to be substituted are passed in as the List result from
563+
* generate_subquery_params or generate_subquery_vars.
496564
*
497565
* The given testexpr has already been recursively processed by
498566
* process_sublinks_mutator. Hence it can no longer contain any
@@ -502,18 +570,13 @@ make_subplan(PlannerInfo *root, SubLink *slink, Node *testexpr, bool isTopQual)
502570
staticNode*
503571
convert_testexpr(PlannerInfo*root,
504572
Node*testexpr,
505-
intrtindex,
506-
List**righthandIds)
573+
List*subst_nodes)
507574
{
508-
Node*result;
509575
convert_testexpr_contextcontext;
510576

511577
context.root=root;
512-
context.rtindex=rtindex;
513-
context.righthandIds=NIL;
514-
result=convert_testexpr_mutator(testexpr,&context);
515-
*righthandIds=context.righthandIds;
516-
returnresult;
578+
context.subst_nodes=subst_nodes;
579+
returnconvert_testexpr_mutator(testexpr,&context);
517580
}
518581

519582
staticNode*
@@ -528,47 +591,17 @@ convert_testexpr_mutator(Node *node,
528591

529592
if (param->paramkind==PARAM_SUBLINK)
530593
{
531-
/*
532-
* We expect to encounter the Params in column-number sequence. We
533-
* could handle non-sequential order if necessary, but for now
534-
* there's no need. (This is also a useful cross-check that we
535-
* aren't finding any unexpected Params.)
536-
*/
537-
if (param->paramid!=list_length(context->righthandIds)+1)
594+
if (param->paramid <=0||
595+
param->paramid>list_length(context->subst_nodes))
538596
elog(ERROR,"unexpected PARAM_SUBLINK ID: %d",param->paramid);
539597

540-
if (context->rtindex)
541-
{
542-
/* Make the Var node representing the subplan's result */
543-
Var*newvar;
544-
545-
newvar=makeVar(context->rtindex,
546-
param->paramid,
547-
param->paramtype,
548-
param->paramtypmod,
549-
0);
550-
551-
/*
552-
* Copy it for caller.NB: we need a copy to avoid having
553-
* doubly-linked substructure in the modified parse tree.
554-
*/
555-
context->righthandIds=lappend(context->righthandIds,
556-
copyObject(newvar));
557-
return (Node*)newvar;
558-
}
559-
else
560-
{
561-
/* Make the Param node representing the subplan's result */
562-
Param*newparam;
563-
564-
newparam=generate_new_param(context->root,
565-
param->paramtype,
566-
param->paramtypmod);
567-
/* Record its ID */
568-
context->righthandIds=lappend_int(context->righthandIds,
569-
newparam->paramid);
570-
return (Node*)newparam;
571-
}
598+
/*
599+
* We copy the list item to avoid having doubly-linked
600+
* substructure in the modified parse tree. This is probably
601+
* unnecessary when it's a Param, but be safe.
602+
*/
603+
return (Node*)copyObject(list_nth(context->subst_nodes,
604+
param->paramid-1));
572605
}
573606
}
574607
returnexpression_tree_mutator(node,
@@ -786,20 +819,24 @@ convert_IN_to_join(PlannerInfo *root, SubLink *sublink)
786819
ininfo->in_operators=in_operators;
787820

788821
/*
789-
* Build the result qual expression. As a side effect,
790822
* ininfo->sub_targetlist is filled with a list of Vars representing the
791823
* subselect outputs.
792824
*/
793-
result=convert_testexpr(root,
794-
sublink->testexpr,
795-
rtindex,
796-
&ininfo->sub_targetlist);
797-
825+
ininfo->sub_targetlist=generate_subquery_vars(root,
826+
subselect->targetList,
827+
rtindex);
798828
Assert(list_length(in_operators)==list_length(ininfo->sub_targetlist));
799829

800830
/* Add the completed node to the query's list */
801831
root->in_info_list=lappend(root->in_info_list,ininfo);
802832

833+
/*
834+
* Build the result qual expression.
835+
*/
836+
result=convert_testexpr(root,
837+
sublink->testexpr,
838+
ininfo->sub_targetlist);
839+
803840
returnresult;
804841
}
805842

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