"Joshua D. Drake" <[EMAIL PROTECTED]> writes: > Heikki Linnakangas <[EMAIL PROTECTED]> wrote: >> Why is that useful?
> For knowing how long checkpoints are taking. If they are taking too > long you may need to adjust your bgwriter settings, and it is a > serious drag to parse postgresql logs for this info. 1. To do anything useful along those lines, you would need to look at a lot of checkpoints over time, which is what log_checkpoints is good for. This patch only tells you about the latest, which isn't very useful for making any good decisions about parameters. 2. If I read the patch correctly, half of the time what you'd be seeing is the start time of the currently-active checkpoint and the completion time of the prior checkpoint. I don't know what those numbers are good for at all. 3. As of PG 8.3, the bgwriter tries very hard to make the elapsed time of a checkpoint be just about checkpoint_timeout * checkpoint_completion_target, regardless of load factors. So unless your settings are completely broken, measuring the actual time isn't going to tell you much. In short: Heikki's question is on point. regards, tom lane -- Sent via pgsql-patches mailing list (pgsql-patches@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-patches