Yan Chunlu wrote: > I have logged one day data and found the checkpoint is rather frequently(detail: > https://gist.github.com/3088338). Not sure if it is normal, but the average time of checkpoint is > about 100sec~200sec, it seems related with my settings: > > 574 checkpoint_segments = 64 > 575 wal_keep_segments = 5000 > > I set checkpoint_segments as a very large value which is because otherwise the slave server always can > not follow the master, should I lower that value? You mean, you set wal_keep_segments high for the standby, right? wal_keep_segments has no impact on checkpoint frequency and intensity. You are right that your checkpoint frequency is high. What is your value of checkpoint_timeout? You can increase the value of checkpoint_segments to decrease the checkpoint frequence, but recovery will take longer then. > or the slow query is about something else? thanks! I guess the question is how saturated the I/O system is during checkpoints. But even if it is very busy, I find it hard to believe that such a trivial statement can take extremely long. Yours, Laurenz Albe -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
