Re: reducing the overhead of frequent table locks - now, with WIP patch

On Sat, Jun 4, 2011 at 2:59 PM, Simon Riggs <simon@2ndquadrant.com> wrote:

>> As you can see, this works out to a bit more than a 4% improvement on
>> this two-core box.  I also got access (thanks to Nate Boley) to a
>> 24-core box and ran the same test with scale factor 100 and
>> shared_buffers=8GB.  Here are the results of alternating runs without
>> and with the patch on that machine:
>>
>> tps = 36291.996228 (including connections establishing)
>> tps = 129242.054578 (including connections establishing)
>> tps = 36704.393055 (including connections establishing)
>> tps = 128998.648106 (including connections establishing)
>> tps = 36531.208898 (including connections establishing)
>> tps = 131341.367344 (including connections establishing)
>>
>> That's an improvement of about ~3.5x.  According to the vmstat output,
>> when running without the patch, the CPU state was about 40% idle.
>> With the patch, it dropped down to around 6%.
>
> Congratulations. I believe that is realistic based upon my investigations.


Tom,

You should look at this. It's good.

The approach looks sound to me. It's a fairly isolated patch and we
should be considering this for inclusion in 9.1, not wait another
year.

I will happily add its a completely different approach to the one I'd
been working on, and even more happily is so different from the Oracle
approach that we are definitely unencumbered by patent issues here.
Well done Robert, Noah.

--
 Simon Riggs                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services