client_heartbeat_server

In a server-to-client connection, clients send heartbeats to the server at this interval (in seconds). 

client_heartbeat_server = interval

The client_heartbeat_server parameter must be specified when a server_timeout_client_connection is set. The client_heartbeat_server interval should be no greater than one third of the server_timeout_client_connection limit.

This setting also ensures that garbage collection occurs on the connection. Collection is triggered by incoming messages and heartbeats. If the size of messages can vary widely or there is not a steady stream of message traffic, can use this parameter to ensure that collection occurs.

When omitted or zero, client_heartbeat_server is disabled.