PostgreSQL 9.0 High Performance by Gregory Smith
Improving database performance requires an equal mix of understanding theoretical concepts and working through hands-on examples. You'll find both here. Many of the examples given will be immediately useful for monitoring and improving your PostgreSQL deployments, providing insight into hard-to-obtain information about your database. This book is aimed at intermediate to advanced database administrators using or planning to use PostgreSQL. Portions will also interest systems administrators looking to build or monitor a PostgreSQL installation, as well as developers interested in advanced database internals that impact application design.