Re: PostgreSQL 9.3 abd CentOS 7 memory usage

Am 12. Oktober 2014 19:33:18 MESZ, schrieb "Elías David" <elias(dot)moreno(dot)tec(at)gmail(dot)com>:
>Hello all,
>
>I have a question regarding the memory usage I'm seeing in one of my
>servers. This servers was recently installed using CentOS 7 and
>PostgreSQL
>9.3
>
>The server has 128GB of ram and we've configured postgresql.conf to use
>as
>much memory as it can (it's a dedicate postgres server after all)
>
>What we're seeing is that even at high peaks of load the server doesn't
>consume more than 14GB, increasing the load doesn't increase ram usage
>equally. We find this odd since we've other servers that are CentOS 6.5
>and
>postgres 9.3 and postgres 8.4, and all use all the ram available.
>
>This particular server was a CentOS 6.5 and postgres 9.1 before and was
>able to use all 128GB of ram, now it doesn't for some reason.
>
>I know that shared memory usage in postgres was changed on 9.3 from sys
>v
>to posix so changing things like shmmax and the like aren't needed
>anymore
>(although we've trying changing those to no effect)
>
>We've even seen out of memory errors on postgres logs a few times when
>the
>server is just using something like 8GB out of 128GB of ram
>
>Has anyone experienced a similar issue or have seen weird memory usage
>patrons with CentOS 7?

What's the on-disk size of your databases and can you estimate the actual working set? How long is this system up and being queried?
I have seen similar when upgrading from 8.4 to 9.3 on Solaris 10, Postgres running in zones. I could not yet investigate further and performance is perfect still.