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Commite76af54

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Fix some issues with LATERAL(SELECT UNION ALL SELECT).
The LATERAL marking has to be propagated down to the UNION leaf querieswhen we pull them up. Also, fix the formerly stubbed-offset_append_rel_pathlist(). It does already have enough smarts to cope withmaking a parameterized Append path at need; it just has to not assume thatthere *must* be an unparameterized path.
1 parent83af58f commite76af54

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4 files changed

+94
-30
lines changed

4 files changed

+94
-30
lines changed

‎src/backend/optimizer/path/allpaths.c

Lines changed: 27 additions & 23 deletions
Original file line numberDiff line numberDiff line change
@@ -661,6 +661,7 @@ set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
661661
intparentRTindex=rti;
662662
List*live_childrels=NIL;
663663
List*subpaths=NIL;
664+
boolsubpaths_valid= true;
664665
List*all_child_pathkeys=NIL;
665666
List*all_child_outers=NIL;
666667
ListCell*l;
@@ -699,19 +700,21 @@ set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
699700
if (IS_DUMMY_REL(childrel))
700701
continue;
701702

702-
/* XXX need to figure out what to do for LATERAL */
703-
if (childrel->cheapest_total_path==NULL)
704-
elog(ERROR,"LATERAL within an append relation is not supported yet");
703+
/*
704+
* Child is live, so add it to the live_childrels list for use below.
705+
*/
706+
live_childrels=lappend(live_childrels,childrel);
705707

706708
/*
707-
* Child is live, so add its cheapest access path to the Append path
708-
* we are constructing for the parent.
709+
* If child has an unparameterized cheapest-total path, add that to
710+
* the unparameterized Append path we are constructing for the parent.
711+
* If not, there's no workable unparameterized path.
709712
*/
710-
subpaths=accumulate_append_subpath(subpaths,
713+
if (childrel->cheapest_total_path)
714+
subpaths=accumulate_append_subpath(subpaths,
711715
childrel->cheapest_total_path);
712-
713-
/* Remember which childrels are live, for logic below */
714-
live_childrels=lappend(live_childrels,childrel);
716+
else
717+
subpaths_valid= false;
715718

716719
/*
717720
* Collect lists of all the available path orderings and
@@ -779,17 +782,20 @@ set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
779782
}
780783

781784
/*
782-
*Next, build an unordered,unparameterizedAppend pathforthe rel.
783-
*(Note: this is correct even if we have zero or one live subpath due to
784-
* constraint exclusion.)
785+
*If we foundunparameterizedpathsforall children, build an unordered,
786+
*unparameterized Append path for the rel. (Note: this is correct even
787+
*if we have zero or one live subpath due toconstraint exclusion.)
785788
*/
786-
add_path(rel, (Path*)create_append_path(rel,subpaths,NULL));
789+
if (subpaths_valid)
790+
add_path(rel, (Path*)create_append_path(rel,subpaths,NULL));
787791

788792
/*
789-
*Buildunparameterized MergeAppend paths based on the collected list of
790-
* child pathkeys.
793+
*Also buildunparameterized MergeAppend paths based on the collected
794+
*list ofchild pathkeys.
791795
*/
792-
generate_mergeappend_paths(root,rel,live_childrels,all_child_pathkeys);
796+
if (subpaths_valid)
797+
generate_mergeappend_paths(root,rel,live_childrels,
798+
all_child_pathkeys);
793799

794800
/*
795801
* Build Append paths for each parameterization seen among the child rels.
@@ -807,11 +813,11 @@ set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
807813
foreach(l,all_child_outers)
808814
{
809815
Relidsrequired_outer= (Relids)lfirst(l);
810-
boolok= true;
811816
ListCell*lcr;
812817

813818
/* Select the child paths for an Append with this parameterization */
814819
subpaths=NIL;
820+
subpaths_valid= true;
815821
foreach(lcr,live_childrels)
816822
{
817823
RelOptInfo*childrel= (RelOptInfo*)lfirst(lcr);
@@ -831,15 +837,15 @@ set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
831837
required_outer,1.0);
832838
if (cheapest_total==NULL)
833839
{
834-
ok= false;
840+
subpaths_valid= false;
835841
break;
836842
}
837843
}
838844

839845
subpaths=accumulate_append_subpath(subpaths,cheapest_total);
840846
}
841847

842-
if (ok)
848+
if (subpaths_valid)
843849
add_path(rel, (Path*)
844850
create_append_path(rel,subpaths,required_outer));
845851
}
@@ -911,13 +917,11 @@ generate_mergeappend_paths(PlannerInfo *root, RelOptInfo *rel,
911917
*/
912918
if (cheapest_startup==NULL||cheapest_total==NULL)
913919
{
914-
/* XXX need to figure out what to do for LATERAL */
915-
if (childrel->cheapest_total_path==NULL)
916-
elog(ERROR,"LATERAL within an append relation is not supported yet");
917-
918920
cheapest_startup=cheapest_total=
919921
childrel->cheapest_total_path;
922+
/* Assert we do have an unparameterized path for this child */
920923
Assert(cheapest_total!=NULL);
924+
Assert(cheapest_total->param_info==NULL);
921925
}
922926

923927
/*

‎src/backend/optimizer/prep/prepjointree.c

Lines changed: 32 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -995,20 +995,45 @@ pull_up_simple_union_all(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
995995
{
996996
intvarno= ((RangeTblRef*)jtnode)->rtindex;
997997
Query*subquery=rte->subquery;
998-
intrtoffset;
998+
intrtoffset=list_length(root->parse->rtable);
999999
List*rtable;
10001000

10011001
/*
1002-
* Append child RTEs to parent rtable.
1003-
*
1002+
* Make a modifiable copy of the subquery's rtable, so we can adjust
1003+
* upper-level Vars in it. There are no such Vars in the setOperations
1004+
* tree proper, so fixing the rtable should be sufficient.
1005+
*/
1006+
rtable=copyObject(subquery->rtable);
1007+
1008+
/*
10041009
* Upper-level vars in subquery are now one level closer to their parent
10051010
* than before. We don't have to worry about offsetting varnos, though,
1006-
* because any such vars must refer to stuff above the level of the query
1007-
* we are pulling into.
1011+
* because the UNION leaf queries can't cross-reference each other.
10081012
*/
1009-
rtoffset=list_length(root->parse->rtable);
1010-
rtable=copyObject(subquery->rtable);
10111013
IncrementVarSublevelsUp_rtable(rtable,-1,1);
1014+
1015+
/*
1016+
* If the UNION ALL subquery had a LATERAL marker, propagate that to all
1017+
* its children. The individual children might or might not contain any
1018+
* actual lateral cross-references, but we have to mark the pulled-up
1019+
* child RTEs so that later planner stages will check for such.
1020+
*/
1021+
if (rte->lateral)
1022+
{
1023+
ListCell*rt;
1024+
1025+
foreach(rt,rtable)
1026+
{
1027+
RangeTblEntry*child_rte= (RangeTblEntry*)lfirst(rt);
1028+
1029+
Assert(child_rte->rtekind==RTE_SUBQUERY);
1030+
child_rte->lateral= true;
1031+
}
1032+
}
1033+
1034+
/*
1035+
* Append child RTEs to parent rtable.
1036+
*/
10121037
root->parse->rtable=list_concat(root->parse->rtable,rtable);
10131038

10141039
/*

‎src/test/regress/expected/join.out

Lines changed: 26 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -3109,6 +3109,32 @@ explain (costs off)
31093109
-> Function Scan on generate_series g
31103110
(4 rows)
31113111

3112+
-- lateral with UNION ALL subselect
3113+
explain (costs off)
3114+
select * from generate_series(100,200) g,
3115+
lateral (select * from int8_tbl a where g = q1 union all
3116+
select * from int8_tbl b where g = q2) ss;
3117+
QUERY PLAN
3118+
------------------------------------------
3119+
Nested Loop
3120+
-> Function Scan on generate_series g
3121+
-> Append
3122+
-> Seq Scan on int8_tbl a
3123+
Filter: (g.g = q1)
3124+
-> Seq Scan on int8_tbl b
3125+
Filter: (g.g = q2)
3126+
(7 rows)
3127+
3128+
select * from generate_series(100,200) g,
3129+
lateral (select * from int8_tbl a where g = q1 union all
3130+
select * from int8_tbl b where g = q2) ss;
3131+
g | q1 | q2
3132+
-----+------------------+------------------
3133+
123 | 123 | 456
3134+
123 | 123 | 4567890123456789
3135+
123 | 4567890123456789 | 123
3136+
(3 rows)
3137+
31123138
-- test some error cases where LATERAL should have been used but wasn't
31133139
select f1,g from int4_tbl a, generate_series(0, f1) g;
31143140
ERROR: column "f1" does not exist

‎src/test/regress/sql/join.sql

Lines changed: 9 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -876,6 +876,15 @@ explain (costs off)
876876
explain (costs off)
877877
selectcount(*)from tenk1 across join lateral generate_series(1,two) g;
878878

879+
-- lateral with UNION ALL subselect
880+
explain (costs off)
881+
select*from generate_series(100,200) g,
882+
lateral (select*from int8_tbl awhere g= q1union all
883+
select*from int8_tbl bwhere g= q2) ss;
884+
select*from generate_series(100,200) g,
885+
lateral (select*from int8_tbl awhere g= q1union all
886+
select*from int8_tbl bwhere g= q2) ss;
887+
879888
-- test some error cases where LATERAL should have been used but wasn't
880889
select f1,gfrom int4_tbl a, generate_series(0, f1) g;
881890
select f1,gfrom int4_tbl a, generate_series(0,a.f1) g;

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