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Commite7261c4

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committed
Adjust setRelhassubclassInRelation() to not perform actual heap_update
when the pg_class.relhassubclass value is already correct. This shouldavoid most cases of the 'tuple concurrently updated' problem thatRobert Creager recently complained about. Also remove a bunch of deadcode in StoreCatalogInheritance() --- it was still computing the completelist of direct and indirect inheritance ancestors, though that list hasnot been needed since we got rid of the pg_ipl catalog.
1 parent4a2c34d commite7261c4

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1 file changed

+34
-86
lines changed

1 file changed

+34
-86
lines changed

‎src/backend/commands/tablecmds.c‎

Lines changed: 34 additions & 86 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.89 2003/10/12 23:19:21 momjian Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.90 2003/10/13 20:02:52 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -47,6 +47,7 @@
4747
#include"utils/acl.h"
4848
#include"utils/builtins.h"
4949
#include"utils/fmgroids.h"
50+
#include"utils/inval.h"
5051
#include"utils/lsyscache.h"
5152
#include"utils/relcache.h"
5253
#include"utils/syscache.h"
@@ -558,7 +559,6 @@ MergeAttributes(List *schema, List *supers, bool istemp,
558559
parent->relname)));
559560

560561
parentOids=lappendo(parentOids,RelationGetRelid(relation));
561-
setRelhassubclassInRelation(RelationGetRelid(relation), true);
562562

563563
parentHasOids |=relation->rd_rel->relhasoids;
564564

@@ -869,7 +869,6 @@ change_varattnos_of_a_node(Node *node, const AttrNumber *newattno)
869869
*Updates the system catalogs with proper inheritance information.
870870
*
871871
* supers is a list of the OIDs of the new relation's direct ancestors.
872-
* NB: it is destructively changed to include indirect ancestors.
873872
*/
874873
staticvoid
875874
StoreCatalogInheritance(OidrelationId,List*supers)
@@ -890,22 +889,27 @@ StoreCatalogInheritance(Oid relationId, List *supers)
890889

891890
/*
892891
* Store INHERITS information in pg_inherits using direct ancestors
893-
* only. Also enter dependencies on the direct ancestors.
892+
* only. Also enter dependencies on the direct ancestors, and make sure
893+
* they are marked with relhassubclass = true.
894+
*
895+
* (Once upon a time, both direct and indirect ancestors were found here
896+
* and then entered into pg_ipl. Since that catalog doesn't exist anymore,
897+
* there's no need to look for indirect ancestors.)
894898
*/
895899
relation=heap_openr(InheritsRelationName,RowExclusiveLock);
896900
desc=RelationGetDescr(relation);
897901

898902
seqNumber=1;
899903
foreach(entry,supers)
900904
{
901-
OidentryOid=lfirsto(entry);
905+
OidparentOid=lfirsto(entry);
902906
Datumdatum[Natts_pg_inherits];
903907
charnullarr[Natts_pg_inherits];
904908
ObjectAddresschildobject,
905909
parentobject;
906910

907911
datum[0]=ObjectIdGetDatum(relationId);/* inhrel */
908-
datum[1]=ObjectIdGetDatum(entryOid);/* inhparent */
912+
datum[1]=ObjectIdGetDatum(parentOid);/* inhparent */
909913
datum[2]=Int16GetDatum(seqNumber);/* inhseqno */
910914

911915
nullarr[0]=' ';
@@ -924,93 +928,23 @@ StoreCatalogInheritance(Oid relationId, List *supers)
924928
* Store a dependency too
925929
*/
926930
parentobject.classId=RelOid_pg_class;
927-
parentobject.objectId=entryOid;
931+
parentobject.objectId=parentOid;
928932
parentobject.objectSubId=0;
929933
childobject.classId=RelOid_pg_class;
930934
childobject.objectId=relationId;
931935
childobject.objectSubId=0;
932936

933937
recordDependencyOn(&childobject,&parentobject,DEPENDENCY_NORMAL);
934938

939+
/*
940+
* Mark the parent as having subclasses.
941+
*/
942+
setRelhassubclassInRelation(parentOid, true);
943+
935944
seqNumber+=1;
936945
}
937946

938947
heap_close(relation,RowExclusiveLock);
939-
940-
/* ----------------
941-
* Expand supers list to include indirect ancestors as well.
942-
*
943-
* Algorithm:
944-
*0. begin with list of direct superclasses.
945-
*1. append after each relationId, its superclasses, recursively.
946-
*2. remove all but last of duplicates.
947-
* ----------------
948-
*/
949-
950-
/*
951-
* 1. append after each relationId, its superclasses, recursively.
952-
*/
953-
foreach(entry,supers)
954-
{
955-
Oidid=lfirsto(entry);
956-
HeapTupletuple;
957-
int16number;
958-
List*current;
959-
List*next;
960-
961-
current=entry;
962-
next=lnext(entry);
963-
964-
for (number=1;;number+=1)
965-
{
966-
tuple=SearchSysCache(INHRELID,
967-
ObjectIdGetDatum(id),
968-
Int16GetDatum(number),
969-
0,0);
970-
if (!HeapTupleIsValid(tuple))
971-
break;
972-
973-
lnext(current)=lconso(((Form_pg_inherits)
974-
GETSTRUCT(tuple))->inhparent,
975-
NIL);
976-
current=lnext(current);
977-
978-
ReleaseSysCache(tuple);
979-
}
980-
lnext(current)=next;
981-
}
982-
983-
/*
984-
* 2. remove all but last of duplicates.
985-
*/
986-
foreach(entry,supers)
987-
{
988-
Oidthisone;
989-
boolfound;
990-
List*rest;
991-
992-
again:
993-
found= false;
994-
thisone=lfirsto(entry);
995-
foreach(rest,lnext(entry))
996-
{
997-
if (thisone==lfirsto(rest))
998-
{
999-
found= true;
1000-
break;
1001-
}
1002-
}
1003-
if (found)
1004-
{
1005-
/*
1006-
* found a later duplicate, so remove this entry.
1007-
*/
1008-
lfirsto(entry)=lfirsto(lnext(entry));
1009-
lnext(entry)=lnext(lnext(entry));
1010-
1011-
gotoagain;
1012-
}
1013-
}
1014948
}
1015949

1016950
/*
@@ -1044,22 +978,36 @@ setRelhassubclassInRelation(Oid relationId, bool relhassubclass)
1044978
{
1045979
RelationrelationRelation;
1046980
HeapTupletuple;
981+
Form_pg_classclasstuple;
1047982

1048983
/*
1049984
* Fetch a modifiable copy of the tuple, modify it, update pg_class.
985+
*
986+
* If the tuple already has the right relhassubclass setting, we
987+
* don't need to update it, but we still need to issue an SI inval
988+
* message.
1050989
*/
1051990
relationRelation=heap_openr(RelationRelationName,RowExclusiveLock);
1052991
tuple=SearchSysCacheCopy(RELOID,
1053992
ObjectIdGetDatum(relationId),
1054993
0,0,0);
1055994
if (!HeapTupleIsValid(tuple))
1056995
elog(ERROR,"cache lookup failed for relation %u",relationId);
996+
classtuple= (Form_pg_class)GETSTRUCT(tuple);
1057997

1058-
((Form_pg_class)GETSTRUCT(tuple))->relhassubclass=relhassubclass;
1059-
simple_heap_update(relationRelation,&tuple->t_self,tuple);
998+
if (classtuple->relhassubclass!=relhassubclass)
999+
{
1000+
classtuple->relhassubclass=relhassubclass;
1001+
simple_heap_update(relationRelation,&tuple->t_self,tuple);
10601002

1061-
/* keep the catalog indexes up to date */
1062-
CatalogUpdateIndexes(relationRelation,tuple);
1003+
/* keep the catalog indexes up to date */
1004+
CatalogUpdateIndexes(relationRelation,tuple);
1005+
}
1006+
else
1007+
{
1008+
/* no need to change tuple, but force relcache rebuild anyway */
1009+
CacheInvalidateRelcache(relationId);
1010+
}
10631011

10641012
heap_freetuple(tuple);
10651013
heap_close(relationRelation,RowExclusiveLock);

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