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Commit1df7a45

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It is possible for ResolveNew to be used to insert a sublink into a
subquery that didn't previously have one. We have traditionally madethe caller of ResolveNew responsible for updating the hasSubLinks flagof the outermost query, but this fails to account for hasSubLinks insubqueries. Fix ResolveNew to handle this. We might later want tochange the calling convention of ResolveNew so that it can fix theouter query too, simplifying callers. But I went with the localizedfix for now. Per bug report from J Smith, 20-Oct-03.
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‎src/backend/rewrite/rewriteManip.c

Lines changed: 28 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteManip.c,v 1.79 2003/09/25 06:58:01 petere Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteManip.c,v 1.80 2003/10/20 20:01:59 tgl Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -99,7 +99,7 @@ bool
9999
checkExprHasSubLink(Node*node)
100100
{
101101
/*
102-
* If a Query is passed, examine it --- but wewill not recurse into
102+
* If a Query is passed, examine it --- but weneed not recurse into
103103
* sub-Queries.
104104
*/
105105
returnquery_or_expression_tree_walker(node,
@@ -755,10 +755,12 @@ AddQual(Query *parsetree, Node *qual)
755755
/*
756756
* Make sure query is marked correctly if added qual has sublinks or
757757
* aggregates (not sure it can ever have aggs, but sublinks
758-
* definitely).
758+
* definitely). Need not search qual when query is already marked.
759759
*/
760-
parsetree->hasAggs |=checkExprHasAggs(copy);
761-
parsetree->hasSubLinks |=checkExprHasSubLink(copy);
760+
if (!parsetree->hasAggs)
761+
parsetree->hasAggs=checkExprHasAggs(copy);
762+
if (!parsetree->hasSubLinks)
763+
parsetree->hasSubLinks=checkExprHasSubLink(copy);
762764
}
763765

764766
/*
@@ -809,10 +811,12 @@ AddHavingQual(Query *parsetree, Node *havingQual)
809811
/*
810812
* Make sure query is marked correctly if added qual has sublinks or
811813
* aggregates (not sure it can ever have aggs, but sublinks
812-
* definitely).
814+
* definitely). Need not search qual when query is already marked.
813815
*/
814-
parsetree->hasAggs |=checkExprHasAggs(copy);
815-
parsetree->hasSubLinks |=checkExprHasSubLink(copy);
816+
if (!parsetree->hasAggs)
817+
parsetree->hasAggs=checkExprHasAggs(copy);
818+
if (!parsetree->hasSubLinks)
819+
parsetree->hasSubLinks=checkExprHasSubLink(copy);
816820
}
817821

818822

@@ -845,6 +849,12 @@ AddInvertedQual(Query *parsetree, Node *qual)
845849
* entry with matching resno from targetlist, if there is one.
846850
* If not, we either change the unmatched Var's varno to update_varno
847851
* (when event == CMD_UPDATE) or replace it with a constant NULL.
852+
*
853+
* Note: the business with inserted_sublink is needed to update hasSubLinks
854+
* in subqueries when the replacement adds a subquery inside a subquery.
855+
* Messy, isn't it? We do not need to do similar pushups for hasAggs,
856+
* because it isn't possible for this transformation to insert a level-zero
857+
* aggregate reference into a subquery --- it could only insert outer aggs.
848858
*/
849859

850860
typedefstruct
@@ -854,6 +864,7 @@ typedef struct
854864
List*targetlist;
855865
intevent;
856866
intupdate_varno;
867+
boolinserted_sublink;
857868
}ResolveNew_context;
858869

859870
staticNode*
@@ -904,6 +915,9 @@ ResolveNew_mutator(Node *node, ResolveNew_context *context)
904915
/* Adjust varlevelsup if tlist item is from higher query */
905916
if (this_varlevelsup>0)
906917
IncrementVarSublevelsUp(n,this_varlevelsup,0);
918+
/* Report it if we are adding a sublink to query */
919+
if (!context->inserted_sublink)
920+
context->inserted_sublink=checkExprHasSubLink(n);
907921
returnn;
908922
}
909923
}
@@ -914,12 +928,17 @@ ResolveNew_mutator(Node *node, ResolveNew_context *context)
914928
{
915929
/* Recurse into RTE subquery or not-yet-planned sublink subquery */
916930
Query*newnode;
931+
boolsave_inserted_sublink;
917932

918933
context->sublevels_up++;
934+
save_inserted_sublink=context->inserted_sublink;
935+
context->inserted_sublink= false;
919936
newnode=query_tree_mutator((Query*)node,
920937
ResolveNew_mutator,
921938
(void*)context,
922939
0);
940+
newnode->hasSubLinks |=context->inserted_sublink;
941+
context->inserted_sublink=save_inserted_sublink;
923942
context->sublevels_up--;
924943
return (Node*)newnode;
925944
}
@@ -938,6 +957,7 @@ ResolveNew(Node *node, int target_varno, int sublevels_up,
938957
context.targetlist=targetlist;
939958
context.event=event;
940959
context.update_varno=update_varno;
960+
context.inserted_sublink= false;
941961

942962
/*
943963
* Must be prepared to start with a Query or a bare expression tree;

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