Indicates how nodes listen to events from other nodes in the Slony-I network.
Structure of sl_listen
integer PRIMARY KEY REFERENCES sl_node>
The ID # (from sl_node.no_id) of the node this listener is operating on
integer PRIMARY KEY REFERENCES sl_path>
The ID # (from sl_node.no_id) of the source node for this listening event
integer PRIMARY KEY REFERENCES sl_path>
The ID # (from sl_node.no_id) of the target node for this listening event