Sun Microsystems, Inc. today announced MySQL™ 5.4, a new version of the world's most popular open source database, designed to deliver significant performance and scalability improvements to MySQL applications. A preview version of MySQL 5.4 is available now for download at http://www.mysql.com/5.4.Today's announcement was made at the seventh annual MySQL Conference & Expo being held this week at the Santa Clara Convention Center. With more than 2,000 attendees, it is the world's largest event for open source database developers, DBAs, vendors and corporate IT managers.