Re: Scaling shared buffer eviction

On Wed, Sep 10, 2014 at 5:46 AM, Mark Kirkwood <
mark(dot)kirkwood(at)catalyst(dot)net(dot)nz> wrote:
>
> On 05/09/14 23:50, Amit Kapila wrote:
>>
>> On Fri, Sep 5, 2014 at 8:42 AM, Mark Kirkwood
>> > FWIW below are some test results on the 60 core beast with this patch
>> applied to 9.4. I'll need to do more runs to iron out the variation,
>> > but it looks like the patch helps the standard (write heavy) pgbench
>> workload a little, and clearly helps the read only case.
>> >
>>
>> Thanks for doing the test. I think if possible you can take
>> the performance data with higher scale factor (4000) as it
>> seems your m/c has 1TB of RAM. You might want to use
>> latest patch I have posted today.
>>
>
> Here's some fairly typical data from read-write and read-only runs at
scale 4000 for 9.4 beta2 with and without the v7 patch (below). I'm not
seeing much variation between repeated read-write runs with the same config
(which is nice - sleep 30 and explicit checkpoint call between each one
seem to help there).
>
> Interestingly, I note anecdotally that (unpatched) 9.4 beta2 seems to be
better at higher client counts than beta1 was...
>
> In terms of the effect of the patch - looks pretty similar to the scale
2000 results for read-write, but read-only is a different and more
interesting story - unpatched 9.4 is noticeably impacted in the higher
client counts, whereas the patched version scales as well (or even better
perhaps) than in the scale 2000 case.

Yeah, that's what I was expecting, the benefit of this patch
will be more at higher client count when there is large data
and all the data can fit in RAM .

Many thanks for doing the performance test for patch.

With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com