Re: wal_buffer tests in

On Wed, 2005-07-27 at 13:30 -0700, Josh Berkus wrote:

> I ran a wal_buffer test series. It appears that increasing the
> wal_buffers is indeed very important for OLTP applications, potentially
> resulting in as much as a 15% average increase in transaction processing.
> What's interesting is that this is not just true for 8.1, it's true for
> 8.0.3 as well.

The most important thing about these tests is that for the first time we
have eliminated much of the post checkpoint noise-and-delay.

Look at the response time charts between

http://khack.osdl.org/stp/302959/results/0/rt.html

and

http://khack.osdl.org/stp/302963/results/0/rt.html

This last set of results is a thing of beauty and I must congratulate
everybody involved for getting here after much effort.

The graphs are smooth, which shows a balanced machine. I'd like to
repeat test 302963 with full_page_writes=false, to see if those response
time spikes at checkpoint drop down to normal level.

I think these results are valid for large DW data loads also.

Best Regards, Simon Riggs