Re: initdb fails

Summary:

I used a workstation where /usr/local/pgsql was mounted, and
which had a larger SHMMAX. initdb worked there.

Then I returned to the server, edited /usr/local/pgsql/data/pgsql.conf
for smaller sizes than the default shared_buffers and max_connections.

Thanks to Pandu and Tom Lane for the following links which describe
in detail the various configuration options:

http://www.powerpostgresql.com/Downloads/annotated_conf_80.html
http://www.postgresql.org/docs/7.4/static/kernel-resources.html

However, when the server SHMMAX is smaller than the size required
by the defaults for shared_buffers and max_connections, I have
not been able to find a way (other than the above), to tell
initdb to use a nondefault values. If this is possible, it
should be documented. The conf file is in the data
directory--initdb will not init if there are existing files
in that directory.

I am doing this for a class where there initially will be only
one connection; and it's not possible to reboot the server at this
time. So I realize my solution is a suboptimal configuration,
but would like to get it up and working.

If there is another way to do this, such as command line options
or environmental values for initdb, I haven't found it.

Thanks for the help and suggestions.

Anne

On 12/7/05, Anne M. Hammond <hammond(at)solarz(dot)colorado(dot)edu> wrote:
> This is running on a Solaris 8 machine.
>
> I installed V 7.4.7 to use with OpenACS.
>
> lcd[34]% /usr/local/pgsql/bin/initdb -D /usr/local/pgsql/data
> ...
> selecting default max_connections... 10
> selecting default shared_buffers... 50
> creating configuration files... ok
> creating template1 database in /usr/local/pgsql/data/base/1... FATAL:
> could not create shared memory segment: Invalid argument
> DETAIL: Failed system call was shmget(key=1, size=1081344, 03600).
> ...
>
> lcd[36]% sysdef -i | grep SHMMAX
> 1048576 max shared memory segment size (SHMMAX)
>
> -----------
> So the shared memory request is greater than the SHMMAX in
> the kernel. If I just wanted to use a smaller number of shared_buffers
> (24), I tried editing /usr/local/pgsql/data/pgsql.conf.
>
> But initdb -D /usr/local/pgsql/data
> finds that the directory is not empty and will not create the databases.
> I have also tried
> setenv PGOPTIONS="shared_buffers = 24"
> and tried initdb, but initdb uses the default number.
>
> Could you tell me how to set shared_buffers from the default so
> that a smaller shared memory segment will be requested?
>
> If you could also tell me how to set the max_connections to a value
> different from the default, that would be great.
>
> Any advice appreciated.
>
> Anne Hammond, University of Colorado at Boulder
>