Using connection pools such as Hikari or Oracle UCP, you can set pool size (init size, idle size, max size) and timeouts (idle/inactive connection timeout).
In hikari, you can configure keepaliveTime (combined with long idle tiemout / max life time) to prevent firewall killing idle TCP connections (SQLRecoverableException: Closed Connection)...
But in Oracle UCP, I did not find option to enable connection "keepalive". So there might be option to set it on jdbc driver level - oracle.net.keepAlive; oracle.net.TCP_KEEPIDLE; oracle.net.TCP_KEEPINTERVAL; oracle.net.TCP_KEEPCOUNT;
Question:
If I enable keepalive on JDBC driver, what happens to pool's idleTimeout when pool size is bigger than minimumIdle?
Would the pool drop such connection as "idle" or would it consider "alive" because of keepalive packets and keep it opened?
Thanks
Based on answers, I have decided not to interfere with ojdbc settings and set ucp to validateConnectionOnBorrow=true, secondsToTrustIdleConnection=1800 to achieve detection of broken connections (because of missing keepalive option in ucp)