Re: Server instrumentation for 8.1

Well, that's clear evidence that the only way we are going to be able to
SIGTERM a backend is it does a query cancel first, then terminates.  I
don't think anything else is going to work cleanly.

---------------------------------------------------------------------------

Rod Taylor wrote:
> > > Exactly.  In theory it probably works fine to allow one backend to exit
> > > via kill -TERM, but it cannot be claimed that that behavior has been
> > > tested to any significant extent --- "fast" shutdown is not stressing it
> > > in the same way.
> > >
> > > I think this is largely a question of someone doing a significant amount
> > > of stress testing: gun live server processes with "kill -TERM" in an
> > > active system, and keep an eye out for resource leaks, held locks, and
> > > so on.  It would be more convincing if the processes getting zapped are
> > > executing a wide variety of SQL, too --- I'd not feel very confident
> > > given only tests of killing, say, pgbench threads.
> > >
> > 
> > Cause I know you wont be satisfied with anecdotal evidence, I thought I would 
> > just say that I have done kill's on specific backends in a high load OLTP 
> > process, with 1000+ active connections, for years and not had a problem with 
> > it yet.   
> > 
> > Not that I wouldn't like to see some specific, thorough testing on the matter, 
> > but I'm perfectly comfortable with the previously provided function.
> 
> I've also used it regularly for a few years with 100 active connections
> in order to get rid of processes which were doing things they shouldn't
> be, and have run into problems.
> 
> It seems about one out of every 20 kills of something holding a heavy
> lock (VACUUM, ALTER TABLE, etc.) will result in a lock table corruption
> being reported within the next few hours, although the pg_locks view
> doesn't show anything interesting, nor do the locks appear to persist as
> other processes can use the structures.
> 
> -- 
> 
> 
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