From: Jim C. Nasby <jnasby@pervasive.com>
To: Carl Youngblood <carl@youngbloods.org>
Cc: pgsql-performance@postgresql.org
Subject: Re: Beginner optimization questions, esp. regarding Tsearch2
Date: Wed, 16 Aug 2006 23:57:23 -0500
Message-ID: <20060817045723.GY21363@pervasive.com> (raw)
In-Reply-To: <e5ed7b690608160834h2560dceg326f6db7be668e87@mail.gmail.com>
References: <e5ed7b690608092100v43590a8epdbdec7afa847c722@mail.gmail.com>
<44DAFB2B.4070307@archonet.com>
<20060815150529.GO27928@pervasive.com>
<e5ed7b690608151147o7f65132do3b9d301f8b2ebc65@mail.gmail.com>
<20060815192145.GI21363@pervasive.com>
<e5ed7b690608160834h2560dceg326f6db7be668e87@mail.gmail.com>
On Wed, Aug 16, 2006 at 09:34:24AM -0600, Carl Youngblood wrote:
> The relevant portion of my sysctl.conf file looks like this:
>
> kernel.shmall = 2097152
> kernel.shmmax = 2147483648
> kernel.shmmni = 4096
> kernel.sem = 250 32000 100 128
> fs.file-max = 65536
>
> I understood it was a good idea to set shmmax to half of available
> memory (2GB in this case). I assume that I need to set shared_buffers
I don't see any reason to do that, so long as you have control over
what's being run on the system. Just set it to 3000000000 or so.
> slightly lower than 2GB for postgresql to start successfully.
>
> Carl
>
> On 8/15/06, Jim C. Nasby <jnasby@pervasive.com> wrote:
> >On Tue, Aug 15, 2006 at 12:47:54PM -0600, Carl Youngblood wrote:
> >> I tried setting it to 2GB and postgres wouldn't start. Didn't
> >> investigate in much greater detail as to why it wouldn't start, but
> >> after switching it back to 1GB it started fine.
> >
> >Most likely because you didn't set the kernel's shared memory settings
> >high enough.
>
> ---------------------------(end of broadcast)---------------------------
> TIP 9: In versions below 8.0, the planner will ignore your desire to
> choose an index scan if your joining column's datatypes do not
> match
>
--
Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
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To: pgsql-performance@postgresql.org
Cc: jnasby@pervasive.com, carl@youngbloods.org
Subject: Re: Beginner optimization questions, esp. regarding Tsearch2
In-Reply-To: <20060817045723.GY21363@pervasive.com>
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