Re: Beginner optimization questions, esp. regarding Tsearch2

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(at)pervasive(dot)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
>

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Jim C. Nasby, Sr. Engineering Consultant jnasby(at)pervasive(dot)com
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