Re: How to interpret view pg_stat_bgwriter

-----Original Message-----
From: Peter Eisentraut [mailto:peter_e(at)gmx(dot)net]
Sent: Thursday, September 18, 2014 6:41 AM
To: Huang, Suya; pgsql-admin(at)postgresql(dot)org
Subject: Re: [ADMIN] How to interpret view pg_stat_bgwriter

>You should rather compare buffers_backend against buffers_checkpoint.

>Also consider graphing these quantities over time so you can see how different workloads affects the results and what the effects of your tuning are.

>Also turn on log_checkpoints and look at the sync times. In my experience that dominates all the bgwriter tuning.

Thank you Peter, comes with more question:

How to compare buffers_backend against buffers_checkpoint?

Below is some statistics of check point activities happened on the day while backend is loading data:

Day Hour Written buffers Write time Sync time Total time
06 107,338 1,475.583s 3.142s 1,478.828s
07 601,672 1,041.482s 348.215s 1,390.153s
08 3,613 361.422s 0.053s 361.535s
09 1,006,704 1,456.898s 14.501s 1,471.545s
10 1,116,463 1,987.896s 6.164s 1,995.11s

Can we tell something about the configuration?

Thanks.
Suay