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

so 3. 4. 2021 v 19:37 odesílatel aditya desai <admad123(at)gmail(dot)com> napsal:

> 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
>

super.

The too big max_connection can cause a lot of problems. You should install
and use pgbouncer or pgpool II.

https://scalegrid.io/blog/postgresql-connection-pooling-part-4-pgbouncer-vs-pgpool/

Regards

Pavel

> 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
>>>
>>