Re: Memory issue on FreeBSD - Mailing list pgsql-general

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
>
>


--
Frank BRONIEWSKI

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