note 1836774
note 1900261
Note 1836774 is particularely useful.
It explain how to disable the idle_connection_timeout so that all connection stay open indefinetely.
Normally, if someone disable the idle_connection_timeout then some connection could be left over until the next reboot of the server, for example when the client machine completly crashed ans left connection open on the hana sql server.Connection left hanging takes precious memory on the server.
tcp_keepalive_* configuration settings allow to detect if the tcp connection was closed by the remote host because of a crash or a network problem and then close it on the hana server after some time.