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Commit47aa95e

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Clean up handling of inherited-table update queries, per bug report
from Sebastian Böck. The fix involves being more consistent aboutwhen rangetable entries are copied or modified. Someday we reallyneed to fix this stuff to not scribble on its input data structuresin the first place...
1 parent1924142 commit47aa95e

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5 files changed

+78
-55
lines changed

5 files changed

+78
-55
lines changed

‎src/backend/optimizer/path/allpaths.c

Lines changed: 2 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.121 2004/08/29 05:06:43 momjian Exp $
11+
* $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.122 2004/10/02 22:39:45 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -124,8 +124,7 @@ set_base_rel_pathlists(Query *root)
124124
/* RangeFunction --- generate a separate plan for it */
125125
set_function_pathlist(root,rel,rte);
126126
}
127-
elseif ((inheritlist=expand_inherited_rtentry(root,rti, true))
128-
!=NIL)
127+
elseif ((inheritlist=expand_inherited_rtentry(root,rti))!=NIL)
129128
{
130129
/* Relation is root of an inheritance tree, process specially */
131130
set_inherited_rel_pathlist(root,rel,rti,rte,inheritlist);
@@ -223,13 +222,6 @@ set_inherited_rel_pathlist(Query *root, RelOptInfo *rel,
223222
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
224223
errmsg("SELECT FOR UPDATE is not supported for inheritance queries")));
225224

226-
/*
227-
* The executor will check the parent table's access permissions when
228-
* it examines the parent's inheritlist entry. There's no need to
229-
* check twice, so turn off access check bits in the original RTE.
230-
*/
231-
rte->requiredPerms=0;
232-
233225
/*
234226
* Initialize to compute size estimates for whole inheritance tree
235227
*/

‎src/backend/optimizer/plan/planner.c

Lines changed: 31 additions & 15 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.175 2004/08/30 02:54:38 momjian Exp $
11+
* $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.176 2004/10/02 22:39:46 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -320,8 +320,7 @@ subquery_planner(Query *parse, double tuple_fraction)
320320
* grouping_planner.
321321
*/
322322
if (parse->resultRelation&&
323-
(lst=expand_inherited_rtentry(parse,parse->resultRelation,
324-
false))!=NIL)
323+
(lst=expand_inherited_rtentry(parse,parse->resultRelation))!=NIL)
325324
plan=inheritance_planner(parse,lst);
326325
else
327326
plan=grouping_planner(parse,tuple_fraction);
@@ -513,7 +512,6 @@ inheritance_planner(Query *parse, List *inheritlist)
513512
{
514513
intchildRTindex=lfirst_int(l);
515514
OidchildOID=getrelid(childRTindex,parse->rtable);
516-
intsubrtlength;
517515
Query*subquery;
518516
Plan*subplan;
519517

@@ -526,22 +524,40 @@ inheritance_planner(Query *parse, List *inheritlist)
526524
subplans=lappend(subplans,subplan);
527525

528526
/*
529-
* It's possible that additional RTEs got added to the rangetable
530-
* due to expansion of inherited source tables (see allpaths.c).
531-
* If so, we must copy 'em back to the main parse tree's rtable.
527+
* XXX my goodness this next bit is ugly. Really need to think about
528+
* ways to rein in planner's habit of scribbling on its input.
532529
*
533-
* XXX my goodness this is ugly. Really need to think about ways to
534-
* rein in planner's habit of scribbling on its input.
530+
* Planning of the subquery might have modified the rangetable,
531+
* either by addition of RTEs due to expansion of inherited source
532+
* tables, or by changes of the Query structures inside subquery
533+
* RTEs. We have to ensure that this gets propagated back to the
534+
* master copy. However, if we aren't done planning yet, we also
535+
* need to ensure that subsequent calls to grouping_planner have
536+
* virgin sub-Queries to work from. So, if we are at the last
537+
* list entry, just copy the subquery rangetable back to the master
538+
* copy; if we are not, then extend the master copy by adding
539+
* whatever the subquery added. (We assume these added entries
540+
* will go untouched by the future grouping_planner calls. We are
541+
* also effectively assuming that sub-Queries will get planned
542+
* identically each time, or at least that the impacts on their
543+
* rangetables will be the same each time. Did I say this is ugly?)
535544
*/
536-
subrtlength=list_length(subquery->rtable);
537-
if (subrtlength>mainrtlength)
545+
if (lnext(l)==NULL)
546+
parse->rtable=subquery->rtable;
547+
else
538548
{
539-
List*subrt;
549+
intsubrtlength=list_length(subquery->rtable);
550+
551+
if (subrtlength>mainrtlength)
552+
{
553+
List*subrt;
540554

541-
subrt=list_copy_tail(subquery->rtable,mainrtlength);
542-
parse->rtable=list_concat(parse->rtable,subrt);
543-
mainrtlength=subrtlength;
555+
subrt=list_copy_tail(subquery->rtable,mainrtlength);
556+
parse->rtable=list_concat(parse->rtable,subrt);
557+
mainrtlength=subrtlength;
558+
}
544559
}
560+
545561
/* Save preprocessed tlist from first rel for use in Append */
546562
if (tlist==NIL)
547563
tlist=subplan->targetlist;

‎src/backend/optimizer/prep/prepunion.c

Lines changed: 32 additions & 26 deletions
Original file line numberDiff line numberDiff line change
@@ -14,7 +14,7 @@
1414
*
1515
*
1616
* IDENTIFICATION
17-
* $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.116 2004/08/29 05:06:44 momjian Exp $
17+
* $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.117 2004/10/02 22:39:47 tgl Exp $
1818
*
1919
*-------------------------------------------------------------------------
2020
*/
@@ -705,24 +705,23 @@ find_all_inheritors(Oid parentrel)
705705
*whole inheritance set (parent and children).
706706
*If not, return NIL.
707707
*
708-
* When dup_parent is false, the initially given RT index is part of the
709-
* returned list (if any).When dup_parent is true, the given RT index
710-
* is *not* in the returned list; a duplicate RTE will be made for the
711-
* parent table.
708+
* Note that the original RTE is considered to represent the whole
709+
* inheritance set. The first member of the returned list is an RTE
710+
* for the same table, but with inh = false, to represent the parent table
711+
* in its role as a simple member of the set. The original RT index is
712+
* never a member of the returned list.
712713
*
713714
* A childless table is never considered to be an inheritance set; therefore
714715
* the result will never be a one-element list. It'll be either empty
715716
* or have two or more elements.
716717
*
717-
* NOTE: after this routine executes, the specified RTE will always have
718-
* its inh flag cleared, whether or not there were any children. This
719-
* ensures we won't expand the same RTE twice, which would otherwise occur
720-
* for the case of an inherited UPDATE/DELETE target relation.
721-
*
722-
* XXX probably should convert the result type to Relids?
718+
* Note: there are cases in which this routine will be invoked multiple
719+
* times on the same RTE. We will generate a separate set of child RTEs
720+
* for each invocation. This is somewhat wasteful but seems not worth
721+
* trying to avoid.
723722
*/
724723
List*
725-
expand_inherited_rtentry(Query*parse,Indexrti,booldup_parent)
724+
expand_inherited_rtentry(Query*parse,Indexrti)
726725
{
727726
RangeTblEntry*rte=rt_fetch(rti,parse->rtable);
728727
OidparentOID;
@@ -734,12 +733,14 @@ expand_inherited_rtentry(Query *parse, Index rti, bool dup_parent)
734733
if (!rte->inh)
735734
returnNIL;
736735
Assert(rte->rtekind==RTE_RELATION);
737-
/* Always clear the parent's inh flag, see above comments */
738-
rte->inh= false;
739736
/* Fast path for common case of childless table */
740737
parentOID=rte->relid;
741738
if (!has_subclass(parentOID))
739+
{
740+
/* Clear flag to save repeated tests if called again */
741+
rte->inh= false;
742742
returnNIL;
743+
}
743744
/* Scan for all members of inheritance set */
744745
inhOIDs=find_all_inheritors(parentOID);
745746

@@ -749,37 +750,42 @@ expand_inherited_rtentry(Query *parse, Index rti, bool dup_parent)
749750
* table once had a child but no longer does.
750751
*/
751752
if (list_length(inhOIDs)<2)
753+
{
754+
/* Clear flag to save repeated tests if called again */
755+
rte->inh= false;
752756
returnNIL;
753-
/* OK, it's an inheritance set; expand it */
754-
if (dup_parent)
755-
inhRTIs=NIL;
756-
else
757-
inhRTIs=list_make1_int(rti);/* include original RTE in result */
757+
}
758758

759+
/* OK, it's an inheritance set; expand it */
760+
inhRTIs=NIL;
759761
foreach(l,inhOIDs)
760762
{
761763
OidchildOID=lfirst_oid(l);
762764
RangeTblEntry*childrte;
763765
IndexchildRTindex;
764766

765-
/* parent will be in the list too; skip it if not dup requested */
766-
if (childOID==parentOID&& !dup_parent)
767-
continue;
768-
769767
/*
770768
* Build an RTE for the child, and attach to query's rangetable
771769
* list. We copy most fields of the parent's RTE, but replace
772-
* relation real name and OID.Note that inh will be false at
773-
* this point.
770+
* relation OID, and set inh = false.
774771
*/
775772
childrte=copyObject(rte);
776773
childrte->relid=childOID;
774+
childrte->inh= false;
777775
parse->rtable=lappend(parse->rtable,childrte);
778776
childRTindex=list_length(parse->rtable);
779-
780777
inhRTIs=lappend_int(inhRTIs,childRTindex);
781778
}
782779

780+
/*
781+
* The executor will check the parent table's access permissions when
782+
* it examines the parent's inheritlist entry. There's no need to
783+
* check twice, so turn off access check bits in the original RTE.
784+
* (If we are invoked more than once, extra copies of the child RTEs
785+
* will also not cause duplicate permission checks.)
786+
*/
787+
rte->requiredPerms=0;
788+
783789
returninhRTIs;
784790
}
785791

‎src/backend/optimizer/util/clauses.c

Lines changed: 11 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.180 2004/08/29 05:06:44 momjian Exp $
11+
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.181 2004/10/02 22:39:48 tgl Exp $
1212
*
1313
* HISTORY
1414
* AUTHORDATEMAJOR EVENT
@@ -3254,10 +3254,20 @@ query_tree_mutator(Query *query,
32543254
CHECKFLATCOPY(newrte->subquery,rte->subquery,Query);
32553255
MUTATE(newrte->subquery,newrte->subquery,Query*);
32563256
}
3257+
else
3258+
{
3259+
/* else, copy RT subqueries as-is */
3260+
newrte->subquery=copyObject(rte->subquery);
3261+
}
32573262
break;
32583263
caseRTE_JOIN:
32593264
if (!(flags&QTW_IGNORE_JOINALIASES))
32603265
MUTATE(newrte->joinaliasvars,rte->joinaliasvars,List*);
3266+
else
3267+
{
3268+
/* else, copy join aliases as-is */
3269+
newrte->joinaliasvars=copyObject(rte->joinaliasvars);
3270+
}
32613271
break;
32623272
caseRTE_FUNCTION:
32633273
MUTATE(newrte->funcexpr,rte->funcexpr,Node*);

‎src/include/optimizer/prep.h

Lines changed: 2 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group
88
* Portions Copyright (c) 1994, Regents of the University of California
99
*
10-
* $PostgreSQL: pgsql/src/include/optimizer/prep.h,v 1.45 2004/08/29 04:13:08 momjian Exp $
10+
* $PostgreSQL: pgsql/src/include/optimizer/prep.h,v 1.46 2004/10/02 22:39:49 tgl Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -52,8 +52,7 @@ extern Plan *plan_set_operations(Query *parse, List **sortClauses);
5252

5353
externList*find_all_inheritors(Oidparentrel);
5454

55-
externList*expand_inherited_rtentry(Query*parse,Indexrti,
56-
booldup_parent);
55+
externList*expand_inherited_rtentry(Query*parse,Indexrti);
5756

5857
externNode*adjust_inherited_attrs(Node*node,
5958
Indexold_rt_index,Oidold_relid,

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