Re: Speed up Clog Access by increasing CLOG buffers

On 09/23/2016 05:10 AM, Amit Kapila wrote:

On Fri, Sep 23, 2016 at 5:14 AM, Tomas Vondra
<tomas.vondra@2ndquadrant.com> wrote:

On 09/21/2016 08:04 AM, Amit Kapila wrote:

(c) Although it's not visible in the results, 4.5.5 almost perfectly
eliminated the fluctuations in the results. For example when 3.2.80 produced
this results (10 runs with the same parameters):

    12118 11610 27939 11771 18065
    12152 14375 10983 13614 11077

we get this on 4.5.5

    37354 37650 37371 37190 37233
    38498 37166 36862 37928 38509

Notice how much more even the 4.5.5 results are, compared to 3.2.80.

how long each run was?  Generally, I do half-hour run to get stable results.

10 x 5-minute runs for each client count. The full shell script driving the benchmark is here: http://bit.ly/2doY6ID and in short it looks like this:

    for r in `seq 1 $runs`; do
        for c in 1 8 16 32 64 128 192; do
            psql -c checkpoint
            pgbench -j 8 -c $c ...
        done
    done