Hi All! Current pg_upgrade copy XID into new cluster, but not it epoch. Why?
Without epoch from old cluster txid_current() in upgraded database return lower value than before upgrade. This break, for example, PgQ and it must be fixed by hand after upgrade with pg_resetxlog. PS: see http://lists.pgfoundry.org/pipermail/skytools-users/2014-April/001812.html -- Sergey Burladyan