When to use MySQL vs PgSQL?
madkangas: This question is 11 hrs old, and nobody has mentioned Postgres' need for periodic "VACUUM" operations? Seriously?If you are running a system with significant data churn (think: a Reuters news feed expiring at N days), Postgres is at a massive disadvantage if you're concerned with system throughput. Postgres 8.4's rewritten Free Space Map looks promising, but 8.4 was just announced in beta on 4/15/2009. In 8.3 or earlier, you can expect significant latency if "VACUUM" is going to touch any significant percentage of your table size.Given sufficient data churn with a Postgres system in a processing pipeline, we can be talking about an hour or more for the "VACUUM" operation per evening. Yes, I speak from experience. The MySQL (5.0.45 InnoDB) systems downstream from these Postgres DBs have zero measurable latency due to space-recovery operations.