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 D.2.15 Changes in MySQL Cluster-4.1.5 (16 Sep 2004)
 ---------------------------------------------------
 
 Functionality added or changed:
 
    * Many queries in MySQL Cluster are executed as range scans or full
      table scans. All queries that don't 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]'.  * In fact, `[NDBD]', `[MYSQLD]', and
      `[NDB_MGMD]' are now the preferred designations, although the
      older ones will continue to be supported for some time to come in
      order to maintain backward compatibility.
 
    * 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.
 
 Bugs fixed:
 
    * Quite a few bugs fixed.
 

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