Client timeout controls

In some customer environments where users connect over VPNs to the Netezza Performance Server system, users might encounter issues where active SQL sessions timeout because of VPN/TCP connection settings in the customer environment. For these environments, Netezza Performance Server adds TCP KEEPALIVE packet support with the following new settings in the /nz/data/postgresql.conf file:

tcp_keepidle

The number of seconds between keepalive messages that are sent on an otherwise idle database connection. A value of 0 uses the system default (7200 seconds). The idle timeout can be used to keep connections from being closed by your network controls (such as firewalls, agents, or network management software) that have idle session timeout settings. In general, your tcp_keepidle setting should be less than the network idle timeout settings. If the setting is longer than the network timeout, the network could close the idle database connections.

tcp_keepinterval

The number of seconds to wait for a keepalive response before retransmitting the message. A value of 0 uses the system default (75 seconds).

tcp_keepcount

The number of retransmission attempts that must occur before the connection is considered dead. A value of 0 uses the system default (9 attempts).