While MySQL is developed by MySQL AB, PostgreSQL is truly open-source in that anyone can contribute to its source code, says Geoff Davidson, CEO of PostgreSQL Inc. His company provides support, consulting, training, and custom-development services for PostgreSQL users, but unlike MySQL AB doesn't sell commercial database licenses.

PostgreSQL is "a serious database-users' database" that competes head-to-head with the likes of Oracle and IBM DB2, Davidson says. It has capabilities MySQL lacks, including stored procedures, triggers, and views. But it still lacks some items most commercial databases have, such as encryption and row-level locking, according to a report from the Aberdeen Group. Version 7.5, due out around October, will offer a point-in-time recovery feature.

Netezza Corp. adopted PostgreSQL as the core of the database it developed in 2000-2001 to run inside its Netezza Performance Server 8000 data warehouse system. That allowed developers to focus on other tasks and shortened the startup's time-to-market by a year or more, says co-founder and CEO Jit Saxena.

With so much going for PostgreSQL, why has MySQL taken the lead in the open-source database race? MySQL has a friendlier user interface, Davidson says. "And we"ve got a publicity gap."