Asynchronous queries - processing listen (notify) in a procedural language

Hi there,

I'd like to make a real-time enabled database and I need to process data
asynchronously. Usually, there are many quick inserts sometimes causing
vast updates. I can't use triggers and rules because the transactions
are really long when there is the update (upgrade) needed.

Is there a way how to listen and trigger the notify messages in the
database (+-)immediately and/or to execute additional (trigger) queries
in other transactions?

In Oracle there is ON COMMIT trigger and an anonymous transaction that
allows commit inside triggers. However this is not possible in Postgres.
Moreover I can't know the check interval of the listening procedures in
an external application (can be anything from millis to days). I was so
desperate that I was thinking about own logging function.

Many thanks, Petr