Re: Request: pg_cancel_backend variant that handles 'idle in transaction' sessions

2015-11-04 21:31 GMT+01:00 Merlin Moncure <mmoncure(at)gmail(dot)com>:

> On Wed, Nov 4, 2015 at 2:09 PM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
> wrote:
> > 2015-11-04 20:35 GMT+01:00 Merlin Moncure <mmoncure(at)gmail(dot)com>:
> >>
> >> On Wed, Nov 4, 2015 at 11:26 AM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com
> >
>
> >> > it doesn't help. How I can set transaction_timeout if I have series of
> >> > slow
> >> > statements? In this case I cannot to set transaction_timeout before
> any
> >> > statement or after any success statement.
> >>
> >> Not quite following you. The client has to go:
> >> BEGIN;
> >> SET transaction_timeout = x;
> >> ....
> >
> > where is the point when transaction_timeout start? In BEGIN or in SET
> > transaction_timeout ?
>
> transaction start (BEGIN).
>
> > How I can emulate transaction_idle_timeout? Can I refresh
> > transaction_timeout?
>
> Well, for my part, I'd probably set default to around an hour with
> longer running batch driven tasks having to override.
>
> > My issue isn't long statements, but broken client, that is broken in
> wrong
> > state - connect is still active, but no any statement will coming.
>
> Right, 'Idle in transaction'. Agree that a setting directed purely at
> that problem could set a much lower timeout, say, 5 minutes or less
> since it almost never comes up in real applications. In fact, in 15
> years of postgres development, I've never seen 'idle transaction' that
> indicated anything but application malfunction.
>
> That being said, hour timeout for general case would work for me. It
> would only have to be set lower for very busy OLTP databases where
> continuous vacuum is essential. In those cases, I don't mind forcing
> all batch processes to disclose in advance they are running long.
>

If I have a statement_timeout 20minutes, what can be transaction_timeout?
hour or 2 hours. If you don't know how much statements are in transaction,
then is pretty difficult to set it.

One hour is nothing for bigger databases with mix OLAP/OLTP and the age for
massive used OLAP.

Regards

Pavel

>
> merlin
>