On Sep23, 2011, at 10:41 , Heikki Linnakangas wrote: > On 23.09.2011 11:02, Linas Virbalas wrote: >> On 9/22/11 6:59 PM, "Euler Taveira de Oliveira"<eu...@timbira.com> wrote: >> >>>> If needed, I could do that, if I had the exact procedure... Currently, >>>> during the start of the backup I take the following information: >>>> >>> Just show us the output of pg_start_backup and part of the standby log with >>> the following message 'redo starts at' and the subsequent messages up to the >>> failure. >> >> Unfortunately, it's impossible, because the error message "Could not read >> from file "pg_clog/0001" at offset 32768: Success" is shown (and startup >> aborted) before the turn for "redo starts at" message arrives. > > It looks to me that pg_clog/0001 exists, but it shorter than recovery > expects. Which shouldn't happen, of course, because the start-backup > checkpoint should flush all the clog that's needed by recovery to disk before > the backup procedure begins to them.
Yeah. What confuses me though is that we fail while trying to read from the clog. When do we do that during normal (non-standby) recovery? One other possibility would be that the problem is somehow triggered by vacuum running while the start-backup checkpoint is commencing. That'd explain why the problem goes away with immediate checkpoints, because those make the windows mach smaller. But I haven't got a concrete theory of whats happening.. best regards, Florian Pflug -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
