[pgpool-general: 6366] Re: pgpool performance issues

[Mariel Cherkassky]

The load average was pretty normal in both cases so I dont think that
limited resources are the root cause here. 40% performance loss is pretty
big number, isnt there a way to debug it ?

‫בתאריך יום א׳, 23 בדצמ׳ 2018 ב-13:49 מאת ‪Tatsuo Ishii‬‏ <‪
ishii at sraoss.co.jp‬‏>:‬

> Hi,
>
> Pgpool-II needs to store and forward each network packet from clients
> and PostgreSQL.  So usually about 40% performance loss is expected
> comparing with direct connecting to PostgreSQL.  That says, if your
> application's SELECT reads a lot of rows for example, it may take more
> time.
>
> Another point of consideration is, hardware resources especially CPU,
> memory and network. In your test case #1, on node A only applications
> and walreciver use CPU, On the other hand in test case #2, on node A
> the applications, Pgpool-II and walreciver use CPU. So it maybe
> possible Pgpool-II cannot get enough CPU. Have you checked resource
> usage?
>
> Best regards,
> --
> Tatsuo Ishii
> SRA OSS, Inc. Japan
> English: http://www.sraoss.co.jp/index_en.php
> Japanese:http://www.sraoss.co.jp
>
> > I meant that max_connection is set to 500. I did the same text with
> > num_init_children=500 but same performance(because my app doesnt use in
> > this architecture more then 200 connections..).
> >
> > ‫בתאריך יום א׳, 23 בדצמ׳ 2018 ב-10:29 מאת ‪Pierre Timmermans‬‏ <‪
> > ptim007 at yahoo.com‬‏>:‬
> >
> >> What do you mean by "My db has 500 max connections" ? If you have 500
> >> concurrent connections, then you should set num_init_children to 500,
> >> because now you can have no more than 200 concurrent users (with pgpool
> a
> >> connection is released from the pgpool only if it the session
> disconnects
> >> from postgres)
> >>
> >> Pierre
> >>
> >>
> >> On Sunday, December 23, 2018, 9:26:17 AM GMT+1, Mariel Cherkassky <
> >> mariel.cherkassky at gmail.com> wrote:
> >>
> >>
> >> Hi,
> >> I'm using pgpool and I'm suffering from very poor performance issues
> when
> >> using the pool. I have the next architecture  :
> >> 1)Node A, contains the application,standby database and pgpool service.
> >> 2)Node B contains the primary db and pgpool service that will be used
> only
> >> in failover.
> >>
> >> I did the next 2 tests :
> >> -In the first test, the application on node A access the DB on node B
> >> directly, without connecting to the pool. I run one of our application`s
> >> major procedures and it took 40s.
> >> -In the second test, the application on node A access the pool on node A
> >> and it redirects the queries to node B. I run the same procedure and it
> >> took 3minutes.
> >>
> >> My db has 500 max connections and the application has only 1 user and 1
> db
> >> so I set the num_init_children to be 200 and pool_size to be 1.
> >>
> >> Any idea how can I tune the pgpool ?
> >>
> >> Thanks.
> >> _______________________________________________
> >> pgpool-general mailing list
> >> pgpool-general at pgpool.net
> >> http://www.pgpool.net/mailman/listinfo/pgpool-general
> >>
>
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