On 2024-Oct-07, KK CHN wrote: > On Mon, Oct 7, 2024 at 12:07 AM Alvaro Herrera <alvherre@xxxxxxxxxxxxxx> > wrote: > Where do I have to introduce the TCP keepalives ? in the OS level or > application code level ? > > [root@dbch wildfly-27.0.0.Final]# cat /proc/sys/net/ipv4/tcp_keepalive_time > 7200 > [root@dbch wildfly-27.0.0.Final]# cat /proc/sys/net/ipv4/tcp_keepalive_intvl > 75 > [root@dbch wildfly-27.0.0.Final]# cat > /proc/sys/net/ipv4/tcp_keepalive_probes > 9 > [root@dbch wildfly-27.0.0.Final]# > > These are the default values in the OS level. Do I need to reduce all the > above three values to say 600, 20, 5 ? Or need to be handled in the > application backend code ? My understanding is that these values have no effect unless the socket gets setsockopt( ... , SO_KEEPALIVE, ...) So that's definitely something that the app needs to do -- it's not enabled automatically. With these default settings, the connection would be closed about 2:11 after going quiet, so if your problem manifests only a week later, you would have enough time for these to be cleaned up. But of course you should monitor what happens. > > I wonder if the connections from Wildfly to Postgres use SSL? Because > > there are reported cases where TCP connections are kept and accumulate, > > causing problems -- but apparently SSL is a necessary piece for that to > > happen. > > > No SSL in between Wildfly (8080 ) to PGSQL(5432). Okay, that's unlikely to be relevant then. -- Álvaro Herrera Breisgau, Deutschland — https://www.EnterpriseDB.com/ "Linux transformó mi computadora, de una `máquina para hacer cosas', en un aparato realmente entretenido, sobre el cual cada día aprendo algo nuevo" (Jaime Salinas)
