Re: could not create shared memory segment: Invalid argument - Mailing list pgsql-admin

From Scott Ribe
Subject Re: could not create shared memory segment: Invalid argument
Date
Msg-id 35EBDB73-CF15-40D6-8AEB-F31AF39FDD5D@elevated-dev.com
Whole thread Raw
In response to Re: could not create shared memory segment: Invalid argument  (Ryan King - NOAA Affiliate <ryan.king@noaa.gov>)
List pgsql-admin
On Jul 13, 2015, at 6:49 PM, Ryan King - NOAA Affiliate <ryan.king@noaa.gov> wrote:
>
> Yeah thanks I see I was going the wrong way...thanks.
> So shared_buffers is 15gb and max_conn = 1000.

OK, you haven't shared your OS or hardware setup, but a few general points:

- 15GB is large for PG shared buffers; it usually doesn't help to go that high; remember, shared buffers is a kind of
workingcache, not the whole cache, PG depends on the OS caching of recently-used files; 

- Your shmall is only 16GB. PG may not be the only user of shared memory. It doesn't make sense to have shmall * page
size< shmmax. 

- Also, does your platform have some absolute upper limit on shmmax? 250GB seems awfully high...

- With 1,000 clients, you'd likely benefit from connection pooling; after you get things up, you should consider
pgbouncer.

--
Scott Ribe
scott_ribe@elevated-dev.com
http://www.elevated-dev.com/
https://www.linkedin.com/in/scottribe/
(303) 722-0567 voice







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