Re: backend hangs at immediate shutdown (Re: Back-branch update releases coming in a couple weeks) - Mailing list pgsql-hackers

On 1/30/13 9:11 AM, MauMau wrote:
> When I ran "pg_ctl stop -mi" against the primary, some applications
> connected to the primary did not stop.  The cause was that the backends
> was deadlocked in quickdie() with some call stack like the following. 
> I'm sorry to have left the stack trace file on the testing machine, so
> I'll show you the precise stack trace tomorrow.

I've had similar problems in the past:

http://www.postgresql.org/message-id/1253704891.20834.8.camel@fsopti579.F-Secure.com

The discussion there never quite concluded.  But yes, you need to be
prepared that in rare circumstances SIGQUIT won't succeed and you need
to use SIGKILL.