On Fri, Aug 10, 2012 at 7:19 AM, Tom Lane <t...@sss.pgh.pa.us> wrote:
> Haifeng Liu <liuhaif...@live.com> writes: > > I have a program running like a daemon, which analyze data and write to > postgresql 9.1 on centos 5.8. There is only one connection between my > program and the postgresql database, and I hope the connection may keep > alive all the time. But I failed, the connection will be reset after idle > for about 2 hours. > > > jdbc driver: 9.1-901, connection url has parameter tcpKeepAlive=true; > > postgresql:9.1, keep alive related settings use default > values(commented); > > centos 5.8 64bit, net.ipv4.tcp_keepalive_intvl = 75, probes = 9, time = > 7200. > > IIRC, time = 7200 (seconds) means to start sending keepalive packets > after 2 hours of idle time. So if you have something in the way that is > dropping the connection after 2 hours, these settings will not activate > keepalive soon enough to save it. I'd try setting that to 3600. > I use a much shorter time (300). Why not? The keepalive pings are a trivial amount of data. I've found over the years that router NAT tables are a big offender (probably doesn't apply in this case) ... some drop your internal-to-external IP address mapping after as little as five minutes. Craig > > > There is no firewall or any other device which behaves force idle > connection cleanup. > > Seems pretty darn unlikely given these symptoms. Look harder... > maybe something you thought was just a bridge has got routing behavior. > > BTW, in the real world connections drop for all sorts of reasons, and > kernel keepalive configurations can't prevent them all. You might be > better advised to build some reconnect-after-connection-loss logic into > your application, rather than spending time on making this work. > > regards, tom lane > > - > Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-admin >
