On Mon, 2010-04-19 at 17:44 +0300, Heikki Linnakangas wrote: > > Choices are > > > > 1. Check RecoveryInProgress() once outside of lock, plus wild rumour of > > Murphy > > > > 2. Check RecoveryInProgress() before and after holding lock > > > > 3. Check RecoveryInProgress() while holding lock > > 4. Check RecoveryInProgress() once outside of lock, and scan the > ProcArray anyway, just in case. That's what we did before this patch. > Document that takenDuringRecovery == true means that the snapshot was > most likely taken during recovery, but there is some race conditions > where takenDuringRecovery is true even though the snapshot was taken > just after recovery finished. AFAICS all of the other current uses of > takenDuringRecovery work fine with that.
Checking RecoveryInProgress() is much cheaper than scanning the whole ProcArray, so (4) is definitely worse than 1-3. -- Simon Riggs www.2ndQuadrant.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
