Who is LISTENing?

Hi pgsql-general,

I'm interested in writing a supervisory process that can insure worker processes are
running/spawn new ones if not. These workers will mainly be responsible for LISTENing to
the db, which is emitting triggered_change_notification s.

Is there any means to check a NOTIFY queue to see who or if anyone is LISTEN ing on it?

Links:
http://www.postgresql.org/docs/9.2/interactive/sql-notify.html
http://www.postgresql.org/docs/9.2/interactive/tcn.html

Regards,