On Sun, 2008-09-28 at 14:02 -0400, Tom Lane wrote: > It does nothing AFAICS for the > problem that when restarting archive recovery from a restartpoint, > it's not clear when it is safe to start letting in backends. You need > to get past the highest LSN that has made it out to disk, and there is > no good way to know what that is. > > Unless we can get past this problem the whole thing seems a bit dead > in > the water :-(
I agree the importance of your a problem but don't fully understand the circumstances under which you see a problem arising. AFAICS when we set minRecoveryLoc we *never* unset it. It's recorded in the controlfile, so whenever we restart we can see that it has been set previously and now we are beyond it. So if we crash during recovery and then restart *after* we reached minRecoveryLoc then we resume in safe mode almost immediately. If we crash during recovery before we reached minRecoveryLoc then we continue until we find it. There is a loophole, as described on separate post, but that can be plugged by offering explicit setting of the minRecoveryLoc from recovery.conf. Most people use pg_start_backup() so do not experience the need for that. -- Simon Riggs www.2ndQuadrant.com PostgreSQL Training, Services and Support -- Sent via pgsql-patches mailing list (pgsql-patches@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-patches
