Re: How to interpret view pg_stat_bgwriter

-----Original Message-----
From: Peter Eisentraut [mailto:peter_e@gmx.net]
Sent: Thursday, September 18, 2014 6:41 AM
To: Huang, Suya; pgsql-admin@postgresql.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
theeffects 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