Noted thanks!! On Sun, Apr 4, 2021 at 4:19 PM Pavel Stehule <pavel.steh...@gmail.com> wrote:
> > > ne 4. 4. 2021 v 12:39 odesílatel aditya desai <admad...@gmail.com> napsal: > >> Hi Pavel, >> Notes thanks. We have 64 core cpu and 320 GB RAM. >> > > ok - this is probably good for max thousand connections, maybe less (about > 6 hundred). Postgres doesn't perform well, when there are too many active > queries. Other databases have limits for active queries, and then use an > internal queue. But Postgres has nothing similar. > > > > > > > >> Regards, >> Aditya. >> >> On Sat, Apr 3, 2021 at 11:21 PM Pavel Stehule <pavel.steh...@gmail.com> >> wrote: >> >>> >>> >>> so 3. 4. 2021 v 19:45 odesílatel aditya desai <admad...@gmail.com> >>> napsal: >>> >>>> Yes. I have made suggestions on connection pooling as well. Currently >>>> it is being done from Application side. >>>> >>> >>> It is usual - but the application side pooling doesn't solve well >>> overloading. The behaviour of the database is not linear. Usually opened >>> connections are not active. But any non active connection can be changed to >>> an active connection (there is not any limit for active connections), and >>> then the performance can be very very slow. Good pooling and good setting >>> of max_connections is protection against overloading. max_connection should >>> be 10-20 x CPU cores (for OLTP) >>> >>> Regards >>> >>> Pavel >>> >>> >>> >>> >>>> On Sat, Apr 3, 2021 at 11:12 PM Pavel Stehule <pavel.steh...@gmail.com> >>>> wrote: >>>> >>>>> >>>>> >>>>> so 3. 4. 2021 v 19:37 odesílatel aditya desai <admad...@gmail.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 <admad...@gmail.com> >>>>>> wrote: >>>>>> >>>>>>> Thanks Justin. Will review all parameters and get back to you. >>>>>>> >>>>>>> On Sat, Apr 3, 2021 at 9:11 PM Justin Pryzby <pry...@telsasoft.com> >>>>>>> wrote: >>>>>>> >>>>>>>> On Sat, Apr 03, 2021 at 11:39:19AM -0400, Tom Lane wrote: >>>>>>>> > Bruce Momjian <br...@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 >>>>>>>> >>>>>>>
