On 01/27/2014 07:09 AM, KONDO Mitsumasa wrote:
> (2014/01/23 23:18), Andrew Dunstan wrote:
>> What is more, if the square root calculation is affecting your
>> benchmarks, I
>> suspect you are benchmarking the wrong thing.
> I run another test that has two pgbench-clients in same time, one is
> select-only-query and another is executing 'SELECT *
> pg_stat_statement' query in every one second. I used v6 patch in this
> test.
>
The issue of concern is not the performance of pg_stat_statements, AUIU.
The issue is whether this patch affects performance generally, i.e. is
there a significant cost in collecting these extra stats. To test this
you would compare two general pgbench runs, one with the patch applied
and one without. I personally don't give a tinker's cuss about whether
the patch slows down pg_stat_statements a bit.
cheers
andrew