Fixed a bug that allowed use of database names containing a
            ‘.’ character. This fixes a
            serious security issue when mysqld is run
            as root.
          
Fixed bug when thread creation failed (could happen when doing a lot of connections in a short time).
            Fixed some problems with FLUSH TABLES and
            TEMPORARY tables. (Problem with freeing
            the key cache and error Can't reopen
            table....)
          
            Fixed a problem in InnoDB with other
            character sets than latin1 and another
            problem when using many columns.
          
            Fixed bug that caused a core dump when using a very complex
            query involving DISTINCT and summary
            functions.
          
            Added SET TRANSACTION ISOLATION LEVEL ...
          
            Added SELECT ... FOR UPDATE.
          
Fixed bug where the number of affected rows was not returned when MySQL was compiled without transaction support.
            Fixed a bug in UPDATE where keys weren't
            always used to find the rows to be updated.
          
            Fixed a bug in CONCAT_WS() where it
            returned incorrect results.
          
            Changed CREATE ... SELECT and
            INSERT ... SELECT to not allow concurrent
            inserts as this could make the binary log hard to repeat.
            (Concurrent inserts are enabled if you are not using the
            binary or update log.)
          
            Changed some macros to be able to use fast mutex with
            glibc 2.2.
          
This is a translation of the MySQL Reference Manual that can be found at dev.mysql.com. The original Reference Manual is in English, and this translation is not necessarily as up to date as the English version.

