Re: Trying to understand postgres crash

On Thu, Dec 22, 2011 at 7:29 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Hanns Hartman <hwhartman(at)gmail(dot)com> writes:
>> I'm running postgres 8.3.17 on a redhat linux mips derivative and I've
>> observed a postgres crash and the subsequent messages in my postgres
>> debug log.
>
>> 2011-12-21 19:08:49 UTC - LOG:  shutting down
>> 2011-12-21 19:08:49 UTC - PANIC:  concurrent transaction log activity
>> while database system is shutting down
>> 2011-12-21 19:08:49 UTC - LOG:  background writer process (PID 1423)
>> was terminated by signal 6: Aborted
>> 2011-12-21 19:08:49 UTC - LOG:  terminating any other active server processes
>
> Best guess is that something sent the background writer process a
> SIGUSR2 signal.  The first two messages indicate that it received such
> a signal, tried to shut down, and panicked when it noticed that other
> processes were still writing to xlog.  The postmaster wouldn't (or at
> least shouldn't, and hasn't been observed to) send such a signal while
> it still has other live children, so I think you ought to look around
> for other possible sources of a signal.
>
>                        regards, tom lane

Thanks for the advice. I'll look around our code base.

One other thought, my current setup mainly interacts with postgresql
via libpq and very rarely via psql. I have four connections open to
postgresql, two of which are connected to one database and two
connected to another. Could that set up or some bad usage of libpq be
leading to this signal being generated?

thanks
-HH