PG Phriday: 10 Ways to Ruin Performance: Indexing the World
An easy way to give Postgres (PostgreSQL) a performance boost is to judiciously use indexes based on queries observed in the system. For most situations, this is as simple as indexing columns that are referenced frequently in WHERE clauses. Postgres is one of the few database engines that takes this idea even further with partial indexes. Unfortunately as a consequence of insufficient exposure, most DBAs and users are unfamiliar with this extremely powerful functionality.