StartupCLOG

I notice that StartupCLOG zeroes out entries later than the nextxid when
we complete recovery in StartupXLOG, reason given is safety in case we
crash.

ISTM that we should also do that whenever we see a Shutdown Checkpoint
in WAL, since that can be caused by a shutdown immediate, shutdown abort
or crash. In each of those cases its possible that we would have the
same conditions as exist at the end of WAL.

Can't see a failure case of importance though, just wanted to flag it up
as a possible. Better a false positive with these types of concern.

-- Simon Riggs           www.2ndQuadrant.comPostgreSQL Training, Services and Support