On 1 May 2017 at 09:54, Petr Jelinek <petr.jeli...@2ndquadrant.com> wrote:
> But, I still think we need to restart the tracking after new > xl_running_xacts. Reason for that is afaics any of the catalog snapshots > that we assigned to transactions at the end of SnapBuildCommitTxn might > be corrupted otherwise as they were built before we knew one of the > supposedly running txes was actually already committed and that > transaction might have done catalog changes. Due to the race where LogStandbySnapshot() collects running-xacts info while a concurrent xact commits, such that the xl_xact_commit appears before the xl_running_xacts, but the xl_running_xacts still has the commited xact listed as running, right? Because we update PGXACT only after we write the commit to WAL, so there's a window where an xact is committed in WAL but not shown as committed in shmem. -- Craig Ringer http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
