Re: Proposal: add a debug message about using geqo

If we add that information to EXPLAIN output, the user won't need
access to server logs.

May be we need it in both the places.

On Tue, May 10, 2022 at 6:35 AM KAWAMOTO Masaya <kawamoto(at)sraoss(dot)co(dot)jp> wrote:
>
> Hi,
>
> During query tuning, users may want to check if GEQO is used or not
> to generate a plan. However, users can not know it by simply counting
> the number of tables that appear in SQL. I know we can know it by
> enabling GEQO_DEBUG flag, but it needs recompiling, so I think it is
> inconvenient.
>
> So, I would like to propose to add a debug level message that shows
> when PostgreSQL use GEQO. That enables users to easily see it by
> just changing log_min_messages.
>
> Use cases are as follows:
> - When investigating about the result of planning, user can determine
> whether the plan is chosen by the standard planning or GEQO.
>
> - When tuning PostgreSQL, user can determine the suitable value of
> geqo_threshold parameter.
>
> Best regards.
>
> --
> KAWAMOTO Masaya <kawamoto(at)sraoss(dot)co(dot)jp>
> SRA OSS, Inc. Japan

--
Best Wishes,
Ashutosh Bapat