On 02.12.2010 11:02, Simon Riggs wrote:
> The cause of the issue is that replay starts at one LSN and there is a
> delay until the RunningXacts WAL record occurs. If there was no delay,
> there would be no issue at all. In CreateCheckpoint() we start by
> grabbing the WAInsertLock and later recording that pointer as part of
> the checkpoint record. My proposal is to replace the "grab the lock"
> code with the insert of the RunningXacts WAL record (when wal_level
> set), so that recovery always starts with that record type.
Oh, interesting idea. But AFAICS closing the gap between acquiring the
running-xacts snapshot and writing it to the log is sufficient, I don't
see what moving the running-xacts record buys us. Does it allow some
further simplifications somewhere?
-- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com