Difference between setting the tcp_keekalives in the Greenplum Database or at the Server OS level.
The tcp_keepalives parameters at the OS level are much the same as the tcp_keepalive parameters in the DB level. The difference is that if you set them at the OS level it will affect everything on the system where as you set them only at the DB level it will only affect the DB connections. It is best to adjust the parameters at the DB level first. You need to ensure that the parameters set at the OS level are higher than what you have set at the DB level. If you have a shorter time period set at the OS level then the connections will be closed earlier than what you have set at the DB level.
The tcp_keepalive parameters in the Greenplum Database are:
tcp_keepalives_interval tcp_keepalives_idle tcp_keepalives_count
Further information on these parameters can be found in the Greenplum System Administrators Guide.