On Mon, Sep 29, 2008 at 2:12 PM, Simon Riggs <[EMAIL PROTECTED]> wrote: > > On Mon, 2008-09-29 at 13:39 +0400, Ivan Zolotukhin wrote: > >> This is all not about checkpoints. As I've mentioned in the first >> message, even right after manual run of CHECKPOINT command in psql >> pg_start_backup() takes same time (~10 minutes). > > As explained, there's not very much going on apart from the checkpoint > and that can be problematic. > > What version are you running? > What are your checkpoint_timeout and checkpoint_completion_target > settings? > > My guesses are 8.3, 20 minutes, and default.
You're dead right: 8.3.3, 30 minutes (it's intended), and default. > pg_start_backup() doesn't do an immediate checkpoint, it does a smooth > one, so doing a CHECKPOINT beforehand should make no difference in 8.3. Aham, now I see. Just a few points on pg_start_backup() from user point of view. I personally would prefer to have some control over the process, e.g. it would be nice to have proposed pg_start_backup(label text, immediate_chkpt boolean). But if that's not what you want by some other reason, it would be nice to add at least log notice telling that system is going to make a spreaded checkpoint and it's gonna take this approximate time (one can estimate a time limit from config constants, right?). -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general