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Add CASCADE option to TRUNCATE. Joachim Wieland

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This commit is contained in:
Tom Lane
2006-03-03 03:30:54 +00:00
parent 2a0ba3f8dd
commit 984a6ced3e
12 changed files with 252 additions and 47 deletions
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62
src/backend/catalog/heap.c
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@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/catalog/heap.c,v 1.293 2005/11/22 18:17:08 momjian Exp $
* $PostgreSQL: pgsql/src/backend/catalog/heap.c,v 1.294 2006/03/03 03:30:52 tgl Exp $
*
*
* INTERFACE ROUTINES
@@ -2043,7 +2043,7 @@ heap_truncate_check_FKs(List *relations, bool tempTables)
if (con->contype != CONSTRAINT_FOREIGN)
continue;
/* Not for one of our list of tables */
/* Not referencing one of our list of tables */
if (!list_member_oid(oids, con->confrelid))
continue;
@@ -2066,7 +2066,8 @@ heap_truncate_check_FKs(List *relations, bool tempTables)
get_rel_name(con->conrelid),
get_rel_name(con->confrelid),
NameStr(con->conname)),
errhint("Truncate table \"%s\" at the same time.",
errhint("Truncate table \"%s\" at the same time, "
"or use TRUNCATE ... CASCADE.",
get_rel_name(con->conrelid))));
}
}
@@ -2074,3 +2075,58 @@ heap_truncate_check_FKs(List *relations, bool tempTables)
systable_endscan(fkeyScan);
heap_close(fkeyRel, AccessShareLock);
}
/*
* heap_truncate_find_FKs
* Find relations having foreign keys referencing any relations that
* are to be truncated
*
* This is almost the same code as heap_truncate_check_FKs, but we don't
* raise an error if we find such relations; instead we return a list of
* their OIDs. Also note that the input is a list of OIDs not a list
* of Relations. The result list does *not* include any rels that are
* already in the input list.
*
* Note: caller should already have exclusive lock on all rels mentioned
* in relationIds. Since adding or dropping an FK requires exclusive lock
* on both rels, this ensures that the answer will be stable.
*/
List *
heap_truncate_find_FKs(List *relationIds)
{
List *result = NIL;
Relation fkeyRel;
SysScanDesc fkeyScan;
HeapTuple tuple;
/*
* Must scan pg_constraint. Right now, it is a seqscan because
* there is no available index on confrelid.
*/
fkeyRel = heap_open(ConstraintRelationId, AccessShareLock);
fkeyScan = systable_beginscan(fkeyRel, InvalidOid, false,
SnapshotNow, 0, NULL);
while (HeapTupleIsValid(tuple = systable_getnext(fkeyScan)))
{
Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(tuple);
/* Not a foreign key */
if (con->contype != CONSTRAINT_FOREIGN)
continue;
/* Not referencing one of our list of tables */
if (!list_member_oid(relationIds, con->confrelid))
continue;
/* Add referencer unless already in input or result list */
if (!list_member_oid(relationIds, con->conrelid))
result = list_append_unique_oid(result, con->conrelid);
}
systable_endscan(fkeyScan);
heap_close(fkeyRel, AccessShareLock);
return result;
}