PostgreSQL version:


Specifies the number of seconds of inactivity after which TCP should send a keepalive message to the client. A value of 0 uses the system default. This parameter is supported only on systems that support TCP_KEEPIDLE or an equivalent socket option, and on Windows; on other systems, it must be zero. In sessions connected via a Unix-domain socket, this parameter is ignored and always reads as zero.

On Windows, a value of 0 will set this parameter to 2 hours, since Windows does not provide a way to read the system default value.