Re: SELECT Query taking 200 ms on PostgreSQL compared to 4 ms on Oracle after migration. - Mailing list pgsql-performance

From aditya desai
Subject Re: SELECT Query taking 200 ms on PostgreSQL compared to 4 ms on Oracle after migration.
Date
Msg-id CAN0SRDHi7y3C8k_iXr3ARmy4nr=prkwNGj8tLcH5i+qWfLYCLg@mail.gmail.com
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In response to Re: SELECT Query taking 200 ms on PostgreSQL compared to 4 ms on Oracle after migration.  (Justin Pryzby <pryzby@telsasoft.com>)
Responses Re: SELECT Query taking 200 ms on PostgreSQL compared to 4 ms on Oracle after migration.
List pgsql-performance
Thanks Justin. Will review all parameters and get back to you.

On Sat, Apr 3, 2021 at 9:11 PM Justin Pryzby <pryzby@telsasoft.com> wrote:
On Sat, Apr 03, 2021 at 11:39:19AM -0400, Tom Lane wrote:
> Bruce Momjian <bruce@momjian.us> writes:
> > On Sat, Apr  3, 2021 at 08:38:18PM +0530, aditya desai wrote:
> >> Yes, force_parallel_mode is on. Should we set it off?
>
> > Yes.  I bet someone set it without reading our docs:
>
> >     https://www.postgresql.org/docs/13/runtime-config-query.html#RUNTIME-CONFIG-QUERY-OTHER
>
> > --> Allows the use of parallel queries for testing purposes even in cases
> > --> where no performance benefit is expected.
>
> > We might need to clarify this sentence to be clearer it is _only_ for
> > testing.
>
> I wonder why it is listed under planner options at all, and not under
> developer options.

Because it's there to help DBAs catch errors in functions incorrectly marked as
parallel safe.

--
Justin

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