Re: Memory issue on FreeBSD

From: Achilleas Mantzios <achill(at)matrix(dot)gatewaynet(dot)com>
To: pgsql-general(at)postgresql(dot)org
Cc: Frank Broniewski <brfr(at)metrico(dot)lu>
Subject: Re: Memory issue on FreeBSD
Date: 2012-11-05 14:21:50
Message-ID: 38639385.tcB3JUFGiN@smadev.internal.net
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How do you measure that smth is missing from top? What values do you add?
I am currently running 8.3 but we shouldn't be so far apart top-wise.
What is the reading under SIZE and RES in top for all postgresql processes?
Take note that shared mem should be recorded for each and every postmaster running.

On Δευ 05 Νοε 2012 14:36:44 Frank Broniewski wrote:
> Hi,
>
> thank you for your feedback. I had a look at those commands and their
> output, especially in conjunction with the SEGSZ value from icps -am
>
> Here's an example output:
> # ipcs -am
> Shared Memory:
> T ID KEY MODE OWNER GROUP CREATOR
> CGROUP NATTCH SEGSZ CPID LPID ATIME
> DTIME CTIME
> m 262144 5432001 --rw------- pgsql pgsql pgsql pgsql
> 12 8813993984 45512 45512 13:49:28
> 14:31:29 13:49:28
>
> but frankly this tells me nothing. I can tell that the value SEGSZ is
> right from the start 8813993984 and it doesn't change anymore. The only
> value that changes is the NATTCH value, I observed a range from 8 to 36
> there. I agree that the SEGSZ value matches the 8GB shared buffer, but
> how can I make the connection of my 5GB missing in top? I wonder if this
> might be the maintenance_work_mem, which is set to 4GB?
>
> Many thanks,
>
> Frank
>
> Am 2012-11-05 12:14, schrieb Achilleas Mantzios:
> >
> > ipcs in FreeBSD is a little ... tricky.
> >
> > ipcs -M
> > ipcs -m
> > ipcs -am
> >
> > could be your friends
> >
> > On Δευ 05 Νοε 2012 11:22:46 Frank Broniewski wrote:
> >> Hi,
> >>
> >> I am running a PostgreSQL server on FreeBSD. The system has 32GB memory.
> >> Usually I use top to examine the memory usage of the system. After a
> >> while, a part, approximately 5GB, vanish from top, so that the memory
> >> rounds up to 27GB. After restarting PostgreSQL, I have all 32GB again
> >> available, but then it's already slightly decreasing. It's a standalone
> >> database server. It has an OpenStreetMap world database running with
> >> 353GB data (with indices).
> >>
> >> Some system information:
> >> # uname -r
> >> 9.0-RELEASE-p3
> >> # pg_ctl --version
> >> pg_ctl (PostgreSQL) 9.1.6
> >>
> >> # cat /boot/loader.conf
> >> ...
> >> kern.ipc.semmni=256
> >> kern.ipc.semmns=512
> >> kern.ipc.semmnu=256
> >> kern.ipc.semumr=200
> >> vm.pmap.shpgperproc=400
> >> vm.pmap.pv_entry_max=50331648
> >> ...
> >>
> >> # cat /pgdata/data/postgresql.conf
> >> ...
> >> default_statistics_target = 50 # pgtune wizard 2012-04-04
> >> maintenance_work_mem = 4GB # pgtune wizard 2012-04-04
> >> constraint_exclusion = on # pgtune wizard 2012-04-04
> >> checkpoint_completion_target = 0.9 # pgtune wizard 2012-04-04
> >> effective_cache_size = 24GB # pgtune wizard 2012-04-04
> >> work_mem = 768MB # pgtune wizard 2012-04-04
> >> wal_buffers = 16MB # pgtune wizard 2012-04-04
> >> checkpoint_segments = 60 # 20
> >> shared_buffers = 8GB # pgtune wizard 2012-04-04
> >> max_connections = 100
> >> synchronous_commit = off
> >>
> >>
> >> So any help finding out why my system "looses" some RAM is greatly
> >> appreciated :-) If more information is needed I will gladly provide it.
> >>
> >> Frank
> >>
> >>
> >>
> >>
> > -
> > Achilleas Mantzios
> > IT DEPT
> >
> >
>
>
>
-
Achilleas Mantzios
IT DEPT

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