Re: Tunning FreeeBSD and PostgreSQL

From: "Stephen Howie" <showie(at)centwire(dot)com>
To: "Vivek Khera" <khera(at)kcilink(dot)com>, <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Tunning FreeeBSD and PostgreSQL
Date: 2003-07-15 17:14:43
Message-ID: 005e01c34af4$9578e670$c40712ac@showie
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Vivek,
Thanks, for your reply. May I ask what you system setup is like (i.e.
memory and such)?

----- Original Message -----
From: "Vivek Khera" <khera(at)kcilink(dot)com>
Newsgroups: ml.postgres.performance
To: <pgsql-performance(at)postgresql(dot)org>
Sent: Tuesday, July 15, 2003 11:44 AM
Subject: Re: [PERFORM] Tunning FreeeBSD and PostgreSQL

> >>>>> "SH" == Stephen Howie <showie(at)centwire(dot)com> writes:
>
> SH> Richard-
> SH> That was very helpfull Thanks!
> SH> I still would like some guidance on tunning FreeBSD (shmmax and
shmmaxpgs).
> SH> Do I need to even touch these settings?
>
> Here's what I use on FreeBSD 4.7/4.8. The kernel settings don't hurt
> anything being too large for the SHM values, since they are limits,
> not anything pre-allocated (from my understanding). These settings
> allow for up to 100,000 shared buffers (I currently only use 30,000
> buffers)
>
>
> options SYSVMSG #SYSV-style message queues
>
> # only purpose of this box is to run PostgreSQL, which needs tons of
shared
> # memory, and some semaphores.
> # Postgres allocates buffers in 8k chunks, so tell Postgres to use about
> # 150 fewer than SHMMAXPGS/2 buffers to leave some room for other Postgres
> # shared memory needs.
> options SYSVSHM #SYSV-style shared memory
> # Maximum number of shared memory pages system wide.
> options SHMALL=262144
> # Maximum size, in pages (4k), of a single System V shared memory region.
> options SHMMAXPGS=262144
>
> # only need semaphores for PostgreSQL
> options SYSVSEM #SYSV-style semaphores
> # Maximum number of System V semaphores that can be used on the system at
> # one time.
> options SEMMNI=32
> # Total number of semaphores system wide
> options SEMMNS=512
> # Maximum number of entries in a semaphore map.
> options SEMMAP=256
>
>
> Also, in /etc/sysctl.conf I put
>
> # need lots of files for database
> kern.maxfiles=8000
> # tuning for PostgreSQL
> kern.ipc.shm_use_phys=1
>
>
>
> --
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> Vivek Khera, Ph.D. Khera Communications, Inc.
> Internet: khera(at)kciLink(dot)com Rockville, MD +1-240-453-8497
> AIM: vivekkhera Y!: vivek_khera http://www.khera.org/~vivek/
>
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