Re: Speed up Clog Access by increasing CLOG buffers

On 2016-04-07 18:40:14 +0530, Amit Kapila wrote:
> On Thu, Apr 7, 2016 at 10:16 AM, Andres Freund <andres(at)anarazel(dot)de> wrote:
> >
> > Hi,
> >
> > On 2016-04-07 09:14:00 +0530, Amit Kapila wrote:
> > > On Sat, Apr 2, 2016 at 5:25 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
> wrote:
> > > I have ran exactly same test on intel x86 m/c and the results are as
> below:
> >
> > Thanks for running these tests!
> >
> > > Client Count/Patch_ver (tps) 2 128 256
> > > HEAD – Commit 2143f5e1 2832 35001 26756
> > > clog_buf_128 2909 50685 40998
> > > clog_buf_128 +group_update_clog_v8 2981 53043 50779
> > > clog_buf_128 +content_lock 2843 56261 54059
> > > clog_buf_128 +nocontent_lock 2630 56554 54429
> >
> > Interesting.
> >
> > could you perhaps also run a test with -btpcb-like(at)1 -bselect-only(at)3?

> This is the data with -b tpcb-like(at)1 with 20-min run for each version and I
> could see almost similar results as the data posted in previous e-mail.
>
> Client Count/Patch_ver (tps) 256
> clog_buf_128 40617
> clog_buf_128 +group_clog_v8 51137
> clog_buf_128 +content_lock 54188
>
> For -b select-only(at)3, I have done quicktest for each version and number is
> same 62K~63K for all version, why do you think this will improve
> select-only workload?

What I was looking for was pgbench with both -btpcb-like(at)1
-bselect-only(at)3 specified; i.e. a mixed read/write test. In my
measurement that's where Simon's approach shines (not surprising if you
look at the way it works), and it's of immense practical importance -
most workloads are mixed.

Regards,

Andres