Fix a couple of snapshot management bugs in the new ResourceOwner world:

non-writable large objects need to have their snapshots registered on the
transaction resowner, not the current portal's, because it must persist until
the large object is closed (which the portal does not).  Also, ensure that the
serializable snapshot is recorded by the transaction resource owner too, even
when a subtransaction has changed the current resource owner before
serializable is taken.

Per bug reports from Pavan Deolasee.

1 files changed, 12 insertions, 3 deletions

diff --git a/src/backend/storage/large_object/inv_api.c b/src/backend/storage/large_object/inv_api.c
index 3936260e6cf..14f101adb34 100644
--- a/src/backend/storage/large_object/inv_api.c
+++ b/src/backend/storage/large_object/inv_api.c
@@ -24,7 +24,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/large_object/inv_api.c,v 1.135 2008/11/02 01:45:28 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/large_object/inv_api.c,v 1.136 2008/12/04 14:51:02 alvherre Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -247,7 +247,13 @@ inv_open(Oid lobjId, int flags, MemoryContext mcxt)
 	}
 	else if (flags & INV_READ)
 	{
-		retval->snapshot = RegisterSnapshot(GetActiveSnapshot());
+		/*
+		 * We must register the snapshot in TopTransaction's resowner,
+		 * because it must stay alive until the LO is closed rather than until
+		 * the current portal shuts down.
+		 */
+		retval->snapshot = RegisterSnapshotOnOwner(GetActiveSnapshot(),
+												   TopTransactionResourceOwner);
 		retval->flags = IFS_RDLOCK;
 	}
 	else
@@ -270,8 +276,11 @@ void
 inv_close(LargeObjectDesc *obj_desc)
 {
 	Assert(PointerIsValid(obj_desc));
+
 	if (obj_desc->snapshot != SnapshotNow)
-		UnregisterSnapshot(obj_desc->snapshot);
+		UnregisterSnapshotFromOwner(obj_desc->snapshot,
+									TopTransactionResourceOwner);
+
 	pfree(obj_desc);
 }