Functionality added or changed:
This is the first public alpha release of the current MySQL 5.1 development branch, providing an insight to upcoming features. Although some of these are still under heavy development, this release includes the following new features and changes (in comparison to the current MySQL 5.0 production release):
Partitioning: allows distributing portions of individual tables across a filesystem, according to rules which can be set when the table is created. In effect, different portions of a table are stored as separate tables in different locations, but from the user point of view, the partitioned table is still a single table. See Kapitel 17, Partitionierung, for further information on this functionality. (Author: Mikael Ronström)
Plugin API: MySQL 5.1 adds support for a very flexible plugin API that enables loading and unloading of various components at runtime, without restarting the server. Although the work on this is not finished yet, plugin full-text parsers are a first step in this direction. This allows users to implement their own input filter on the indexed text, enabling full-text search capability on arbitrary data such as PDF files or other document formats. A pre-parser full-text plugin performs the actual parsing and extraction of the text and hands it over to the built-in MySQL full-text search. (Author: Sergey Vojtovich)
          The plugin API requires the mysql.plugin
          table. When upgrading from an older version of MySQL, you
          should run the mysql_fix_privilege_tables
          command to create this table. See
          Abschnitt 5.6, „mysql_fix_privilege_tables — Upgrade von MySQL-Systemtabellen“.
        
          Incompatible change: Plugins
          are installed in the directory named by the
          plugin_dir system variable. This variable
          also controls the location from which the server loads
          user-defined functions (UDFs), which is a change from earlier
          versions of MySQL. That is, all UDF library files now must be
          installed in the plugin directory. When upgrading from an
          older version of MySQL, you must migrate your UDF files to the
          plugin directory.
        
The Instance Manager (IM) now has some additional functionality:
                SHOW  provides a listing of all log files
                used by the instance. (Author: Petr Chardin)
              instance_name
                LOG FILES
                SHOW  retrieves a
                part of the specified log file. (Author: Petr Chardin)
              instance_name
                LOG {ERROR | SLOW | GENERAL}
                size
                SET 
                sets an option to the specified value and writes it to
                the config file See Abschnitt 5.5, „mysqlmanager — Der MySQL Instance Manager“,
                for more details on these new commands. (Author: Petr
                Chardin)
              instance_name.
                option_name=option_value
The performance of boolean full-text searches (using the „+“ Operator) has been improved. See Abschnitt 12.7, „MySQL-Volltextsuche“, for more details about full-text searching. (Author: Sergey Vojtovich)
          VARCHAR fields used in MySQL Cluster tables
          are now variable-sized; that is, they now only allocate as
          much space as required to store the data. Previously, a
          VARCHAR(
          column allocated n+2 bytes (aligned to 4 bytes), regardless if
          the actual inserted value required that much space. (In other
          words, a n)VARCHAR column always required the
          same, fixed, amount of storage as a CHAR
          column of the same size.)
        
          Renamed the table_cache system variable to
          table_open_cache. Any scripts that refer to
          table_cache should be updated to use the
          new name.
        
          Added the table_definition_cache system
          variable. If you use a large number of tables, you can create
          a large table definition cache to speed up opening of tables.
          The table definition cache takes less space and does not use
          file descriptors, unlike the normal table cache.
        
Bugs fixed:
Set functions could not be aggregated in outer subqueries. (Bug#12762)
Dies ist eine Übersetzung des MySQL-Referenzhandbuchs, das sich auf dev.mysql.com befindet. Das ursprüngliche Referenzhandbuch ist auf Englisch, und diese Übersetzung ist nicht notwendigerweise so aktuell wie die englische Ausgabe. Das vorliegende deutschsprachige Handbuch behandelt MySQL bis zur Version 5.1.

