Re: I want tips for debugging deadlocks

Hannu Krosing <hannu@tm.ee> writes:
> I'm in a situation where I urgently need to debug PostgreSQL 7.0.2 
> for deadlocks that it does not notice/timeout

The most likely bet is that you are seeing deadlocks that involve a
buffer spinlock (LockBuffer() in bufmgr.c) --- there's no timeout or
deadlock detection check in that code.  I have been suspicious for
some time that there are deadlocks possible there, but haven't had
any luck getting a reproducible example to study.  (If you can present
a reproducible way to make the problem happen, please post it!)

> Where can I find info about running several concurrent backends 
> under a debugger ?

Just fire up N backends and attach to each one with N instances of gdb.
It's a little confusing but I've done it ...
        regards, tom lane