After MySQL 5.1 was released work started on MySQL 5.2, but then this was renamed to MySQL 6.0. There were many new features introduced in 6.0. But then stabilizing this branch became as huge task. Eventually the decision was made to start of with a stable branch and backport the new features from 6.0. This is how many of the 6.0 features landed in 5.5 and 5.6.

So let's see which features 6.0 brought and were they landed. I'll use the What Is New in MySQL 6.0 section of the MySQL 6.0 Reference Manual for this.

• The Falcon storage engine. This never landed anywhere as far as I know. It's not even included in the …

Robin just wrote a new article, titled A Quick Look at MySQL 6.0’s New Backup, and I thought, that maybe you’d like to also see this in presentation/video format…

At OSCON, Giuseppe actually gave a quick talk at the Sun booth, about our online backup. He also showed how to use it. All examples there, were done with the test-db sample database.

(MySQL Online Backup in Practice, video if the above doesn’t appear)