On Tue, Jun 8, 2010 at 11:14 PM, Greg Smith <greg@xxxxxxxxxxxxxxx> wrote: > Greg Smith wrote: >> >> You don't much with a single snapshot of pg_stat_bgwriter data. Try >> saving this instead: >> select *,now() from pg_stat_bgwriter; >> And then take another snapshot at least a few hours later, preferably the >> next day. With two snapshots and timestamps on them, then it's possible to >> make some sense of the numbers. > > I probably should have explained the next part. I've now shared what I do > with this information at > http://www.pgcon.org/2010/schedule/events/218.en.html > > Basically, if you put the data from the two snapshots into one of the > Statistics Spreadsheet versions, you'll get several derived numbers that pop > out: > > -Average checkpoint frequency > -Average size of each checkpoint > -Average rate at which new buffers are allocated > -Average rate of writes out of the buffer cache > -Percentage of writes done by checkpoints, the background writer LRU > cleaner, and client backends I think you get all or most of that if you just log checkpoints. -- Sent via pgsql-admin mailing list (pgsql-admin@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin
