Re: Sample rate added to pg_stat_statements

On 04.02.2025 20:59, Sami Imseih wrote:
>> To summarize the results of all benchmarks, I compiled them into a table:
> Thanks for compiling the benchmark data above.
>
> The main benefit of this patch will be to give the user
> a toggle if they are observing high spinlock contention
> due to pg_stat_statements which will likely occur
> on larger machines.
>
> I also did not see this thread [1] mentioned in the thread above,
> but one of the reasons pg_stat_statements.track_planning
> was turned off by default was due to the additional spinlock
> acquire to track the planning stats. Bringing this up as sample_rate
> might also be beneficial as well if a user decides to track planning.
>
> Regards,
>
> Sami
>
> [1] https://www.postgresql.org/message-id/flat/2895b53b033c47ccb22972b589050dd9(at)EX13D05UWC001(dot)ant(dot)amazon(dot)com

Thanks for the thread. As we can see, simply enabling or disabling not
only track_planning but also other pg-stat_statements parameters is too
radical a measure for managing performance. With the introduction of
sample_rate,  users now have more flexibility in controlling spinlock
contention. This allows them to balance overhead and statistics
collection rather than completely disabling the feature.

--
Best regards,
Ilia Evdokimov,
Tantor Labs LLC.