Re: Problem with Out of Memory and no more connecction possible

On Thu, Jun 4, 2015 at 5:55 PM, Dmitrii Golub <dmitrii(dot)golub(at)gmail(dot)com>
wrote:

> Hello,
> It's well known behaviour, just use connection pooler
>
> 2015-06-05 0:35 GMT+03:00 AL-Temimi, Muthana <
> muthana(dot)al-temimi(at)tu-harburg(dot)hamburg(dot)de>:
>
>> Hello admins,
>>
>>
>>
>> i have postgresql version 9.1 and those my configurations:
>>
>>
>>
>> max_connection=600
>>
>> shared_buffers=1024M
>>
>> work_mem=4M
>>
>> and all others parameters are default as delivered with postgresql.
>>
>>
>>
>> I installed on Suse Enterprice Linux Server and kernel_shxmem= 2GByte in
>> the sysctl.conf, because if I put 1Gbyte postgresql will never started.
>>
>> The total RAM of the server is 8GB.
>>
>>
>>
>> But when the active connections reach 300 then we get out of memory and I
>> checked the system through “top” and I got 7,8GB used from 8GB and started
>> to swap also. At the same time there are no new connection possible.
>>
>>
>>
>> I have connection pool pgpool II in the front of and the everything with
>> it till now OK. No problem in the system and works fine.
>>
>>
>>
>> Any help will be grateful
>>
>>
>>
>> Best Regards
>>
>>
>>
>> Muthana AL-Temimi
>>
>> M.Sc. Informations- und Kommunikations-Systeme
>>
>>
>>
>> Technische Universitaet Hamburg Harburg
>>
>> -Rechenzentrum-
>>
>> Am Schwarzenberg-Campus 3
>>
>> D-21073 Hamburg
>>
>>
>>
>> Tel.: +49.40.42878.2338
>>
>> Fax.: +49.40.42793.5160
>>
>> E-Mail: m(dot)al(at)tu-harburg(dot)de
>>
>> http://www.tu-harburg.de/rzt
>>
>>
>>
>>
>>
>
>
Keep in mind that work_mem is memory used in addition to shared_buffers.
With work_mem = 4MB and a possible 600 connections max, that could take up
an additional 2.3GB if all connections were in use and doing simple
queries.

But work_mem is something that can have many multiples in use per session
if you have complex queries being run. Read
https://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server for more
info.

Are you running pgpool on the same server? If so, 8GB doesn't sound like
enough memory for what you're trying to do if your concurrent connection
count is going that high.

Keith