I just attended and presented at ConFoo, where I always learn new things. This year, the best talk I attended was by our own Magnus Hagander. Called Integrated Cache Invalidation for Better Hit Rates, it addresses the difficult task of controlling web page cache refresh by providing a reliable mechanism for invalidating the cache when the database changes. It shows how to use triggers and pgq to communicate changes to a Varnish web frontend.
Caching in front of a database is often risky. However, with triggers, pgq, and Varnish, proper invalidation can be accomplished, dramatically increasing the scalability of database-backed websites.
Bruce Momjian is a co-founder of the PostgreSQL Global Development Group, and has worked on PostgreSQL since 1996 as a committer and community leader. He is a frequent speaker and Postgres evangelist and travels worldwide appearing at conferences to help educate the community on the business value of Postgres advances and new technology enhancements. He is the author of PostgreSQL: Introduction and Concepts, published by Addison-Wesley.