Re: rogue process maxing cpu and unresponsive to signals

Jon Jensen <jon@jenseng.com> writes:
> 1. I've tried killing the process using kill from the command-line (INT,
> TERM and HUP), as well as using pg_cancel_backend() via psql.
> 2. I've tried attaching gdb to the renegade process to see what it's
> doing, but that hangs, forcing me to kill gdb (no problems attaching to
> other postgres processes however).

> Any other ideas? I'd like to avoid doing a kill -9 if at all possible.
> The machine is debian (sarge) running postgres 8.1.

I think you'll find that "kill -9" doesn't do anything either, and
the only recourse is a system reboot.  What this sounds like to me
is that the kernel has gotten wedged trying to perform some operation
or other on behalf of that process.  Problems like a stuck disk I/O
request are often found to result in unkillable, un-attachable processes.

How up-to-date is your kernel?  Seen any signs of hardware problems
lately?

            regards, tom lane