We use PgBouncer as well. It's still useful to have a connection pooler within the application for ensuring connections are still good, reconnecting as needed, and making it easy to check out a connection.
that has not worked out well for me in the java world - one connection pooler connecting to another one. unless one of them has ultimate control on timeouts and eviction.
I'm actually very intrigued on if you are seeing actual benefits using r2d2 ... or would using only pgbouncer make it just as efficient.
