A better viewer for PostgreSQL debug trees
If you set debug_print_parse, debug_print_rewritten, or debug_print_plan to true, PostgreSQL will log some of the interesting internal data structures during the query execution. But these logs are usually too long and difficult to inspect.
I recently switched to using Frog to generate my blog. Last week I wrote a little Frog plugin to allow me embed these trees in a nice tree view in blog posts.