The NOTIFY man page writes
When <command>NOTIFY</command> is used to signal the occurrence of
changes
to a particular table, a useful programming technique is to put the
<command>NOTIFY</command> in a rule that is triggered by table updates.
Is using rules here still best practice? This was probably written
before statement triggers were available.
Even if yes, we might want to explain why, since we generally discourage
rule use otherwise.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services