Version 5.1.30 is the first generally available release of MySQL 5.1.  There are several new enhancements included in this long awaited release. Highlights include:

• The addition of partitioning. This allows a user to see a single table even though it is distributed in portions across a filesystem resulting in faster query response times. This is possible because only the relevant partitions of the data need to be referenced.
• The incorporation of row-based and mixed replication. Row-based replication allows for the replication of data changes between master and slave servers. The highly efficient mixed replication allows for the handling of either statement-based or row-based replication.
• The introduction of a plugin API. This flexible plugin facilitates the loading and unloading of various components at runtime. This is done without restarting the server.   
• The addition of an event scheduler. This allows recurring SQL-based tasks to execute on the database server automatically. This tool is similar to the idea of the Unix crontab.
• The added flexibility of server log tables. This allows for more versatility in the server’s logging capabilities for general query and slow query log entries.
• The incorporation of an upgrade program. This program checks for incompatibilities with the current MySQL Server and repairs them if necessary.
• The release of MySQL Cluster as a separate product. MySQL Cluster now includes the NDBCLUSTER storage engine. Other enhancements include replication support, disk data storage, and better backups.

Find a full list of what’s new in MySQL 5.1.30 here.