On Fri, 2009-01-16 at 19:12 +0100, Gianni Ciolli wrote: > On Fri, Jan 16, 2009 at 06:39:11PM +0100, Gianni Ciolli wrote: > (...) > > During a Warm Standby session using current HEAD I obtained the > > following error on the standby node:
I think I understand the cause of these bugs in CVS HEAD now. In various places in current HEAD we throw a checkpoint when we want to be certain that all buffers have been flushed. In recovery, a checkpoint isn't always a restartpoint for two reasons: timing and rmgr state. This gives both a cause for the error and an explanation of why it does not occur consistently. ISTM this could likely effect previous releases as well. We need to put some marker into WAL to allow the same actions to be repeated in recovery. We can't just force these "correctness checkpoints" to be restartpoints because they might be invalid, but we can force CheckPointGuts() (or something less) without updating the control file. With regard to various changes I have in motion, the CheckPointGuts() would need to be executed in full before further WAL replay occurs, so would need to be executed by the Startup process and not by the bgwriter to ensure we performed the correct sequence of actions. CHECKPOINT_FORCE might be the right indicator of when to do take special action in recovery, not sure. Will look at this again later. -- Simon Riggs www.2ndQuadrant.com PostgreSQL Training, Services and Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
