The Watchdog cleans up after improperly terminated processes. For example, it releases any locks or shared-memory structures that those processes might hold.
Notes
If the Watchdog finds a process that is no longer active, it releases all the appropriate record locks, backs out any live transactions, releases any shared-memory locks, and closes the connection. If the lost process is a server, it disconnects and cleans up all appropriate remote clients.
If the process was changing shared memory when it terminated, shared memory is in an inconsistent state; the Watchdog forces a shutdown to protect the database.
The Watchdog cannot detect lost remote clients because remote clients are not associated with a process. Instead, a network protocol timeout mechanism notifies the server that the network connection was lost.