PostgreSQL prefers regular maintenance, and there is a recipe discussing planning maintenance (the last one).

We recognize that you're here for a reason and are looking for a quick solution to your needs. You're probably thinking, "fix me first, and I'll plan later." So off we go!

PostgreSQL provides a utility command named VACUUM, which is a jokey name for a garbage collector that sweeps up all the bad things and fixes them—or at least, most of them. That's the single most important thing you need to remember to do—I say "single" because closely connected to that is the ANALYZE command, which collects optimizer statistics. It's possible to run VACUUM and ANALYZE as a single joint command, VACUUM ANALYZE, and those actions are automatically executed for you when appropriate by autovacuum, a special background process that forms part of the PostgreSQL server.

VACUUM performs a range of cleanup activities, some of them too complex to describe without a whole sideline into their...