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RemoveAttrDefaultById() neglected to obtain exclusive lock on the

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relation being modified.  In most paths of control we'd already have
such a lock, but if we were dropping the default due to a cascaded
delete of some function it depended on, maybe not.
This commit is contained in:
Tom Lane 2002-08-02 21:54:34 +00:00
parent 21cf6b2166
commit 154f26ff59
1 changed files with 14 additions and 1 deletions
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15
src/backend/catalog/heap.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.215 2002/08/02 18:15:05 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.216 2002/08/02 21:54:34 tgl Exp $
*
*
* INTERFACE ROUTINES
@ -1027,6 +1027,7 @@ RemoveAttrDefaultById(Oid attrdefId)
{
Relation attrdef_rel;
Relation attr_rel;
Relation myrel;
ScanKeyData scankeys[1];
SysScanDesc scan;
HeapTuple tuple;
@ -1036,6 +1037,7 @@ RemoveAttrDefaultById(Oid attrdefId)
/* Grab an appropriate lock on the pg_attrdef relation */
attrdef_rel = heap_openr(AttrDefaultRelationName, RowExclusiveLock);
/* Find the pg_attrdef tuple */
ScanKeyEntryInitialize(&scankeys[0], 0x0,
ObjectIdAttributeNumber, F_OIDEQ,
ObjectIdGetDatum(attrdefId));
@ -1051,6 +1053,10 @@ RemoveAttrDefaultById(Oid attrdefId)
myrelid = ((Form_pg_attrdef) GETSTRUCT(tuple))->adrelid;
myattnum = ((Form_pg_attrdef) GETSTRUCT(tuple))->adnum;
/* Get an exclusive lock on the relation owning the attribute */
myrel = heap_open(myrelid, AccessExclusiveLock);
/* Now we can delete the pg_attrdef row */
simple_heap_delete(attrdef_rel, &tuple->t_self);
systable_endscan(scan);
@ -1081,7 +1087,14 @@ RemoveAttrDefaultById(Oid attrdefId)
CatalogCloseIndices(Num_pg_attr_indices, idescs);
}
/*
* Our update of the pg_attribute row will force a relcache rebuild,
* so there's nothing else to do here.
*/
heap_close(attr_rel, RowExclusiveLock);
/* Keep lock on attribute's rel until end of xact */
heap_close(myrel, NoLock);
}
/* ----------------------------------------------------------------