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

Hi Justin/Bruce/Pavel,
Thanks for your inputs. After setting force_parallel_mode=off Execution
time of same query was reduced to 1ms from 200 ms. Worked like a charm. We
also increased work_mem to 80=MB. Thanks again.

Regards,
Aditya.

On Sat, Apr 3, 2021 at 9:14 PM aditya desai <admad123(at)gmail(dot)com> wrote:

> Thanks Justin. Will review all parameters and get back to you.
>
> On Sat, Apr 3, 2021 at 9:11 PM Justin Pryzby <pryzby(at)telsasoft(dot)com> wrote:
>
>> 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
>>
>