Re: SELECT Query taking 200 ms on PostgreSQL compared to 4 ms on Oracle after migration.

On Sat, Apr 03, 2021 at 11:39:19AM -0400, Tom Lane wrote:
> Bruce Momjian <bruce(at)momjian(dot)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