pgsql_stats is a plug-in for Rails 1.2 and later extracted from ZingLists. It gathers the statistics from the PostgreSQL statistics collector and makes it easy to display them in a view. Helpers make it simple to visually highlight the largest tables in your database and see how your tables and indexes are making use of the buffer cache. The initial release also includes some very basic index analysis, and the goal is to expand this in the future to provide performance optimization hints across the entire database.
Please see the blog post for installation and usage instructions.