Fix bug with view locking code.

LockViewRecurese() obtains view relation using heap_open() and passes
it to get_view_query() to get view info. It immediately closes the
relation then uses the returned view info by calling
LockViewRecurse_walker().  Since get_view_query() returns a pointer
within the relcache, the relcache should be kept until
LockViewRecurse_walker() returns. Otherwise the relation could point
to a garbage memory area.

Fix is moving the heap_close() call after LockViewRecurse_walker().

Problem reported by Tom Lane (buildfarm is unhappy, especially prion
since it enables -DRELCACHE_FORCE_RELEASE cpp flag), fix by me.

diff --git a/src/backend/commands/lockcmds.c b/src/backend/commands/lockcmds.c
index 1dbb35f6315d574b84c156cf8f39383c5da29d73..b247c0fe2e16345754de2baa92c199e5ad75df90 100644 (file)
--- a/src/backend/commands/lockcmds.c
+++ b/src/backend/commands/lockcmds.c
@@ -263,7 +263,6 @@ LockViewRecurse(Oid reloid, Oid root_reloid, LOCKMODE lockmode, bool nowait)
 
        view = heap_open(reloid, NoLock);
        viewquery = get_view_query(view);
-       heap_close(view, NoLock);
 
        context.root_reloid = root_reloid;
        context.lockmode = lockmode;
@@ -272,6 +271,8 @@ LockViewRecurse(Oid reloid, Oid root_reloid, LOCKMODE lockmode, bool nowait)
        context.viewoid = reloid;
 
        LockViewRecurse_walker((Node *) viewquery, &context);
+
+       heap_close(view, NoLock);
 }
 
 /*