As Aidan recently pointed out on performance-list
(http://archives.postgresql.org/pgsql-performance/2007-03/msg00110.php),
our documentation doesn't mention that CLUSTER isn't MVCC-safe.
The right way to fix it is to fix CLUSTER, of course, but we should
still document the current behavior in older branches.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com