Re: Add min and max execute statement time in pg_stat_statement

On 17/02/15 03:07, Petr Jelinek wrote:
> On 17/02/15 03:03, Andrew Dunstan wrote:
>>
>> On 02/16/2015 08:57 PM, Andrew Dunstan wrote:
>>>
>>> On 02/16/2015 08:48 PM, Petr Jelinek wrote:
>>>> On 17/02/15 01:57, Peter Geoghegan wrote:
>>>>> On Mon, Feb 16, 2015 at 4:44 PM, Petr Jelinek <petr(at)2ndquadrant(dot)com>
>>>>> wrote:
>>>>>> We definitely want this feature, I wished to have this info many
>>>>>> times.
>>>>>
>>>>> I would still like to see a benchmark.
>>>>>
>>>>>
>>>>
>>>> Average of 3 runs of read-only pgbench on my system all with
>>>> pg_stat_statement activated:
>>>> HEAD: 20631
>>>> SQRT: 20533
>>>> SQRTD: 20592
>>>>
>>>>
>>>
>>>
>>> So using sqrtd the cost is 0.18%. I think that's acceptable.
>>>
>>
>> Actually, sqrt/sqrtd is not called in accumulating the stats, only in
>> the reporting function. So it looks like the difference here should be
>> noise. Maybe we need some longer runs.
>>
>
> Yes there are variations between individual runs so it might be really
> just that, I can leave it running for much longer time tomorrow.
>

Ok so I let it run for more than hour on a different system, the
difference is negligible - 14461 vs 14448 TPS. I think there is bigger
difference between individual runs than between the two versions...

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