Appendix D. MySQL Release Notes

This appendix lists the changes from version to version in MySQL through the latest version of MySQL 5.5, which is currently MySQL 5.5.31. We offer a version of the Manual for each series of MySQL releases (5.0, 5.1, and so forth). For information about changes in another release series of the MySQL database software, see the corresponding version of this Manual.

We update these notes as we add new features in the 5.5 series, so that everybody can follow the development process.

We tend to update these notes at the same time we make changes to MySQL. If you find a recent version of MySQL listed here that you cannot find on our download page (http://dev.mysql.com/downloads/), it means that the version has not yet been released.

The date mentioned with a release version is the date of the last Bazaar ChangeSet on which the release was based, not the date when the packages were made available. The binaries are usually made available a few days after the date of the tagged ChangeSet, because building and testing all packages takes some time.

The manual included in the source and binary distributions may not be fully accurate when it comes to the release changelog entries, because the integration of the manual happens at build time. For the most up-to-date release changelog, please refer to the online version instead.

Previously, MySQL development proceeded by including a large set of features and moving them over many versions within a release series through several stages of maturity (Alpha, Beta, and so forth). This development model had a disadvantage in that problems with only part of the code could hinder timely release of the whole.

MySQL development now uses a milestone model. The move to this model provides for more frequent milestone releases, with each milestone proceeding through a small number of releases having a focus on a specific subset of thoroughly tested features. Following the releases for one milestone, development proceeds with the next milestone; that is, another small number of releases that focuses on the next small set of features, also thoroughly tested.

MySQL 5.5.0-m2 is the first release for Milestone 2. The new features of this milestone may be considered to be initially of beta quality. For subsequent Milestone 2 releases, we use increasing version numbers (5.5.1 and higher) while continuing to employ the "-m2" suffix. For Milestone 3, we change the suffix to "-m3". Version designators with "-alpha" or "-beta" suffixes are no used.

You may notice that the MySQL 5.5.0 release is designated as Milestone 2 rather than Milestone 1. This is because MySQL 5.4 was actually designated as Milestone 1, although we had not yet begun referring to milestone numbers as part of version numbers at the time.