Often times, when we make changes in a database we also want to "do something useful." Simply sending and email or triggering an ETL into a non-postgres system like Lucene is also a bit convoluted and painful. By using asynchronous messaging, we can make this simple. There have been a few attempts in the past to add into postgres the ability to queue external tasks, but with AMQP you get a complete package.
pg_amqp marries the AMQP standard into PostgreSQL providing transaction-aware message queueing. We'll talk about how easy it can be to get an AMQP enabled postgresql up and running with pg_amqp. We'll also discuss the caveats that exist in pg_amqp (currently implementing AMQP 0.8) and how AMQP 1.0 will eventually solve them.