Re: hot restart of posgtresql

Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> Tom Lane wrote:
>> ngaleyev(at)wavelengthmail(dot)com writes:
>>> heres my sysctl:
>>> kernel.shmmax=4294967296
>>> kernel.shmall=536870912
>>
>> Why have you got SHMALL set to half a GB when you have Postgres
>> configured to ask for over 3 GB?

> Hmm, isn't shmall measured in pages?

Depends on platform, which he didn't say ... but if it is a platform
that measures in pages, I wonder whether that value is provoking an
integer overflow somewhere. I don't think Linux allows more than
about 2 million, for instance.

> I think the problem may be that he changed the settings in sysctl.conf
> but he hasn't rebooted since, so the kernel is running with other
> settings. Trying with sysctl -w to change the actual values might prove
> helpful.

But his DB *was* running before, so somehow the active sysctl settings
are different now than they were. I was betting on there having been
a manual tweak to sysctl that never got made in the configuration file,
and thus got lost on reboot.

regards, tom lane