Oracle’s Mysql Blog has a very good post that provides an overview of some of the improvements that you can expect in the upcoming Mysql 5.5 release.
This writeup focuses mainly on the changes as they relate to performance and scalability, however the author (Rob Young) expresses his plans to discuss other aspects as well, sometime in the near future.
Here are just a few of the topics covered by Rob:
- Improved Default Thread Concurrency
- Improved Recovery Performance
- Multiple Buffer Pool Instances
- Native Asynchronous I/O for Linux
- Improved Metadata Locking Within Transactions
- Better performance on Windows based installs
At some point I hope to continue my testing and benchmarking of several different versions of Mysql such as MariaDB, Percona and Mysql 5.5. However for production databases we will be sticking with the Mysql 5.1.x code branch for the foreseeable feature.