kern.ipc.sem* and postgresql

[Andrew Gould]

On Wed, Aug 27, 2008 at 2:10 PM, Albert Shih <Albert.Shih at obspm.fr> wrote:

> Hi all
>
> Classic question but I don't find the answers by google.
>
> If I've server with X procs, N Go ram and if the only purpose of this
> server is to run a postgresql daemon how can I known/calculate what I must
> give to those variable
>
>        set kern.ipc.semmni=?
>        set kern.ipc.semmns=?
>        set kern.ipc.semmnu=?
>
> and
>
>        kern.ipc.shmall=?
>        kern.ipc.shmmax=?
>        kern.ipc.semmap=?
>
> Once those variables is determined how can I known/calculate the variable
> in postgresql.conf ?
>
> shared_buffers = 32MB                   # min 128kB or max_connections*16kB
>                                        # (change requires restart)
> #temp_buffers = 8MB                     # min 800kB
> #max_prepared_transactions = 5          # can be 0 or more
>                                        # (change requires restart)
> # Note:  Increasing max_prepared_transactions costs ~600 bytes of shared
> # memory
> # per transaction slot, plus lock space (see max_locks_per_transaction).
> #work_mem = 1MB                         # min 64kB
> #maintenance_work_mem = 16MB            # min 1MB
> #max_stack_depth = 2MB                  # min 100kB
> # - Free Space Map -
> max_fsm_pages = 204800                  # min max_fsm_relations*16, 6 bytes
> each
>                                        # (change requires restart)
> #max_fsm_relations = 1000               # min 100, ~70 bytes each
>                                        # (change requires restart)
>
> # - Kernel Resource Usage -
>
> #max_files_per_process = 1000           # min 25
>
> ?
>
> Regards.
>
> JAS
> --
> Albert SHIH
> SIO batiment 15
> Observatoire de Paris Meudon
> 5 Place Jules Janssen
> 92195 Meudon Cedex
> Heure local/Local time:
> Mer 27 aoû 2008 21:06:02 CEST


I used to perform financial/clinical data analysis using a PostgreSQL server
on FreeBSD, which entailed complex questions and a lot of data processing
per query.  I adjusted the PostgreSQL server using the configuration files;
but never found a need to adjust the FreeBSD kernel.

You can find information to help you at the links below.

Managing Kernel Resources section of the manual:
http://www.postgresql.org/docs/current/static/kernel-resources.html

Hardware performance tuning section of the PostgreSQL manual:
http://www.postgresql.org/files/documentation/books/aw_pgsql/hw_performance/

Global User Configuration Guide at Varlena's website:
http://www.varlena.com/varlena/GeneralBits/Tidbits/annotated_conf_e.html

Best of luck,

Andrew