Re: 8.3 beta testing suggestions welcome

On Fri, 30 Nov 2007, Kevin Grittner wrote:

>> checkpoint_segments = 50

Here's how I'm reading your data:

16:43:11 : Checkpoint start
16:44:23 : Checkpoint ends [ 1:22 long]
1:01 passes
16:45:24 : Checkpoint start
16:46:36 : checkpoint ends [1:22 long]

If you're getting a checkpoint every minute or so, the number of 
checkpoint segments you're using is still far too low to really take 
advantage of the new checkpoint spreading features.  You want to make that 
high enough that it's several minutes between them.  It's not unusual to 
set a much higher checkpoint_segments during bulk loading than you'd 
necessarily want for actual production use.

One thing that would make your reports more useful:  in the spots in your 
log where you're labeling [checkpoint starting] etc., if you could include 
the new message spit out by turning on checkpoint_log there it would help. 
That's the one that says how much data was written.

Did you ever write something to save snapshots of pg_stat_bgwriter? 
Those would be interesting to see on the same time scale as well.

--
* Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD