Re: Backend timeout

Scott Marlowe wrote:
> On Tue, Sep 16, 2008 at 7:21 AM, Dragan Ciric <dragan.ciric@a-asoft.com> wrote:
>
>>Hi!
>>
>>We need some help.
>>Sometimes we have broken connections with backend ( postgresql server ).
>>When this occurs, we have "idle in transaction" indication on server side. Can you
>>answer us, how long will server stay in this state and what happens with this
>>broken connection ( client started transaction, but can't send commit or rollback )?
>
>
> If the client socket on the other end has simply disappeared, then the
> connection will be harvested approximately net.ipv4.tcp_keepalive_time
> + net.ipv4.tcp_keepalive_probes * net.ipv4.tcp_keepalive_intvl seconds
> later.  On default setups, this is something like 7200 + 90 * 9 for a
> total of 8010 seconds.  i.e. just over an hour.
Not to be picky but 60 sec * 60 min = 3600 sec = 1 hour so
the above timeout would be just over 2 hours.
>
> On later model postgresql's you can change these settings for just the
> pgsql server to something more sane, like
>
> net.ipv4.tcp_keepalive_time = 300
> net.ipv4.tcp_keepalive_probes =  3
> net.ipv4.tcp_keepalive_intvl = 30
>
> which get it down to 6.5 minutes or so before stale connections are harvested.
>
> The advantage to using tcp_keepalive is it won't kill living but idle
> connections.
>