[pgpool-general: 6365] Re: pgpool performance issues

[Tatsuo Ishii]

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
>>