Postgres Database Stops Frequently

ganesheinstein

My database server stops frequently and I need to reboot the server to start the postgres again. When I check the logfile there is a message as follows:

IpcMemoryCreate: shmget(key=5432001, size=1466368, 03600) failed: Invalid argument

This error usually means that PostgreSQL's request for a shared memory segment exceeded your kernel's SHMMAX parameter. You can either reduce the request size or reconfigure the kernel with larger SHMMAX.

To reduce the request size (currently 1466368 bytes), reduce
PostgreSQL's shared_buffers parameter (currently 64) and/or
its max_connections parameter (currently 32).

If the request size is already small, it's possible that it is less than
your kernel's SHMMIN parameter, in which case raising the request size or reconfiguring SHMMIN is called for.

The PostgreSQL Administrator's Guide contains more information about shared memory configuration.

On my server I have 1GB of RAM.

Please help how I solve this problem.

Regards,
ganesh

chriskl

Ummm...doesn't the log message TELL you how to fix the problem? Increase your system's SHMMAX.

Since it's intermittent, it's also likely that you don't have enough SEMMAX either. (Semaphores)

You also have an astonishingly low number of max_connections on shared_buffers. You should have around 1000 shared_buffers at least, not 64. Bump max_connections up as well.

Chris

ganesheinstein

How to change the shared max settings. I have a 1gb of RAM.

Please help. I am newbie to Linux.

Sxooter

you probably are running redhat (you might wanna mention the flavor of linux next time, as RedHat is WAYYY different from say, debian).

anyway, look for a file called sysctl.conf in your /etc directory, and add these lines to it:

kernel.shmall = 320000000
kernel.shmmax = 1280000000