Many queries in MySQL Cluster are executed as range scans or full table scans. All queries that do not use a unique hash index or the primary hash index use this access method. In a distributed system it is crucial that batching is properly performed.

In previous versions, the batch size was fixed to 16 per data node. In this version it is configurable per MySQL Server. So for queries using lots of large scans it is appropriate to set this parameter rather large and for queries using many small scans only fetching a small amount of records it is appropriate to set it low.

The performance of queries can easily change as much as 40% based on how this variable is set.

In future versions more logic will be implemented for assessing the batch size on a per-query basis. Thus, the semantics of the new configuration variable ScanBatchSize are likely to change.

The fixed size overhead of the ndbd process has been greatly decreased. This is also true for the overhead per operation record as well as overhead per table and index.

A number of new configuration variables have been introduced to enable configuration of system buffers. Configuration variables for specifying the numbers of tables, unique hash indexes, and ordered indexes have also been introduced.

New configuration variables: MaxNoOfOrderedIndexes, MaxNoOfUniqueHashIndexes

Configuration variables no longer used: MaxNoOfIndexes (split into the two above).

In previous versions ALTER TABLE, TRUNCATE TABLE, and LOAD DATA were performed as one big transaction. In this version, all of these statements are automatically separated into several distinct transactions.

This removes the limitation that one could not change very large tables due to the MaxNoOfConcurrentOperations parameter.

MySQL CLuster's online backup feature now backs up indexes so that both data and indexes are restored.

In previous versions it was not possible to use NULL in indexes. This is now possible for all supported index types.

Much work has been put onto making AUTO_INCREMENT features work as for other table handlers. Autoincrements as a partial key is still only supported by MyISAM.

In earlier versions, mysqld would crash if the cluster wasn't started with the --ndbcluster option. Now mysqld handles cluster crashes and starts without crashing.

The -i option for initial startup of ndbd has been removed. Initial startup still can be specified by using the --initial option. The reason for this is to ensure that it is clear what takes place when using --initial: this option completely removes all data from the disk and should only be used at initial start, in certain software upgrade cases, and in some cases as a workaround when nodes cannot be restarted successfully.

The management client (ndb_mgm) now has additional commands and more information is printed for some commands such as show.

In previous versions, the files were called ndb_0.. when it wasn't possible to allocate a node ID when starting the node. To ensure that files are not so easily overwritten, these files are now named ndb_pid.., where pid is the process ID assigned by the OS.

The default parameters have changed for ndb_mgmd and ndbd. In particular, they are now started as daemons by default. The -n option has been removed since it could cause confusion as to its meaning (nostart or nodaemon).

In the configuration file, you can now use [NDBD] as an alias for [DB], [MYSQLD] as an alias for [API], and [NDB_MGMD] as an alias for [MGM].

Many more checks for consistency in configuration have been introduced to in order to provide quicker feedback on configuration errors.

In the connect string, it is now possible to use both “;” and “,” as the separator between entries. Thus, "nodeid=2,host=localhost:2200" is equivalent to "nodeid=2;host=localhost:2200".

In the configuration file, it is also possible to use “:” or “=” for assignment values. For example, MaxNoOfOrderedIndexes : 128 and MaxNoOfOrderedIndexes = 128 are equivalent expressions.

The configuration variable names are now case insensitive, so MaxNoOfOrderedIndexes: 128 is equivalent to MAXNOOFORDEREDINDEXES = 128.

It is possible now to set the backup directory separately from the FileSystemPath by using the BackupDir configuration variable.

Log files and trace files can now be placed in any directory by setting the DataDir configuration variable.

FileSystemPath is no longer mandatory and defaults to DataDir.

Queries involving tables from different databases are now supported.

It is now possible to update the primary key.

The performance of ordered indexes has been greatly improved, particularly the maintenance of indexes on updates, inserts and deletes.

Quite a few bugs fixed.