The oldest of the PostgreSQL compatible packages used for connection pooling that's still in development, pgpool-II, improves on the original pgpool in a variety of ways.
Its primary purpose is not just connection pooling, it also provides load balancing and replication related capabilities. It even supports some parallel query setups, where queries can be broken into pieces and spread across nodes where each has a copy of the information being asked about. The pool in pgpool is primarily to handle multiple servers, with the program serving as a proxy server between the clients and a number of databases.
There are a few limitations to pgpool-II setup to serve as a connection pooler. One is that each connection is set up as its own ...
