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MySQL 5.0 Reference Manual :: 19 MySQL Cluster :: 19.13 MySQL Cluster Development Roadmap :: 19.13.2 MySQL 5.1 Development Roadmap for MySQL Cluster
19.14 MySQL Cluster Glossary »
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19.13.2. MySQL 5.1 Development Roadmap for MySQL Cluster

What is said here is a status report based on recent commits to the MySQL 5.1 source tree. It should be noted all 5.1 development is subject to change.

There are currently 4 major new features being developed for MySQL 5.1:

  1. Integration of MySQL Cluster into MySQL replication: This will make it possible to update from any MySQL Server in the cluster and still have the MySQL Replication handled by one of the MySQL Servers in the cluster, with the state of the slave side remaining consistent with the cluster acting as the master.

  2. Support for disk-based records: Records on disk will be supported. Indexed fields including the primary key hash index must still be stored in RAM but all other fields can be on disk.

  3. Variable-sized records.  A column defined as VARCHAR(255) currently uses 260 bytes of storage independent of what is stored in any particular record. In MySQL 5.1 Cluster tables, only the portion of the column actually taken up by the record will be stored. This will make possible a reduction in space requirements for such columns by a factor of 5 in many cases.

  4. User-defined partitioning.  Users will be able to define partitions based on columns that are part of the primary key. The MySQL Server will be able to discover whether it is possible to prune away some of the partitions from the WHERE clause. Partitioning based on KEY, HASH, RANGE, and LIST handlers will be possible, as well as subpartitioning. This feature should also be available for many other handlers, and not only NDB Cluster.

In addition, we are working to increase the 8KB size limit for rows containing columns of types other than BLOB or TEXT in Cluster tables. This is due to the fact that rows are currently fixed in size and the page size is 32,768 bytes (minus 128 bytes for the row header). Currently, this means that if we allowed more than 8KB per record, any remaining space (up to approximately 14,000 bytes) would be left empty. In MySQL 5.1, we plan to fix this limitation so that using more than 8KB in a given row does not result in the remainder of the page being wasted.