Beta Draft: 2017-03-27
This section describes temporary limitations introduced with the MySQL data dictionary.
Manual creation of database directories under the data directory (for example, with mkdir) is unsupported. Manually created database directories are not recognized by the MySQL Server.
Moving data stored in
MyISAMtables by copying and moving
MyISAMdata files is unsupported. Tables moved using this method are not discovered by the server.
Simple backup and restore of individual
MyISAMtables using copied data files is unsupported.
TRUNCATE TABLE, which is mapped to
CREATE TABLEin MySQL 8.0, is temporarily non-atomic. A server exit during a
TRUNCATE TABLEoperation can result in a dropped table. It may also result in orphaned foreign key entries in the
SYS_FOREIGN_COLSdictionary tables if the table contains foreign key constraints.
DDL operations take longer due to writing to storage, undo logs, and redo logs instead of
The period of time during which DDL operations are vulnerable to a server exit is longer due to writing to storage, undo logs, and redo logs instead of
.frmfiles. The minimal risk introduced by this limitation is mostly applicable to restore operations and other operations that load numerous new tables.
With the removal of
.islfiles in MySQL 8.0, offline relocation of file-per-table tablespaces created outside of the MySQL data directory is not supported.
If MySQL exits in the middle of an
ALTER TABLEoperation on an
InnoDBtable, you may be left with an orphan intermediate or temporary table. Removing orphan intermediate and temporary tables is unsupported.