The same publisher (Packt) has a book PostgreSQL 9 Administration Cookbook by Simon Riggs and Hannu Krosing that is equally useful as Greg's High Performance book
I have been working on PostgreSQL for quite a while (2 yrs) now.
I have got "PostgreSQL 9.0 High Performance" book and quite excited to go through it.
Please let me know any source where i can get more books on PG, I am especially looking for books on PG internals, architecture, Backup & Recovery and HA.