Re: running two servers on one machine

Ahhh! Can't seem to make this go away!

Here is the log file entry:

FATAL: could not create shared memory segment: Cannot allocate memory
DETAIL: Failed system call was shmget(key=5432001, size=4030464,
03600).
HINT: This error usually means that PostgreSQL's request for a shared
memory segment exceeded available memory or swap space. To reduce the
request size (currently 4030464 bytes), reduce PostgreSQL's
shared_buffers parameter (currently 300) and/or its max_connections
parameter (currently 23).
The PostgreSQL documentation contains more information about shared
memory configuration.

Following the queue on the postgres web page, I created /etc/
sysctl.conf and added the following five entries:

kern.sysv.shmmax=4194304
kern.sysv.shmmin=1
kern.sysv.shmmni=32
kern.sysv.shmseg=8
kern.sysv.shmall=1024

But when I try to start two servers, I get the same error. Should I
be bumping these numbers up?

Eric

On Mar 30, 2009, at 7:18 PM, Tom Lane wrote:

> Eric Smith <eric_h_smith(at)mac(dot)com> writes:
>> Log file says "could not create shared memory segment". It also says
>> that I should change max_connections or shared_buffers.
>
>> Error message claims that max_connections is 23, but postgresql.conf
>> has this listed as 20.
>
> The autovacuum workers get added on.
>
>> Error message claims that shared_buffers is 300, but postgresql.conf
>> has this listed as 2400kB.
>
> Same thing, different units.
>
> Anyway, you left out the interesting part of the error message,
> ie the kernel error code. If it's "Cannot allocate memory" then
> you probably need to increase SHMALL.
>
> regards, tom lane
>
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