(mysql.info) federated-limitations

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(mysql.info) federated-storage-engine

 
 14.7.3 Limitations of the `FEDERATED' Storage Engine
 ----------------------------------------------------
 
 The following items indicate features that the `FEDERATED' storage
 engine does and does not support:
 
    * In the first version, the remote server must be a MySQL server.
      Support by `FEDERATED' for other database engines may be added in
      the future.
 
    * The remote table that a `FEDERATED' table points to _must_ exist
      before you try to access the table through the `FEDERATED' table.
 
    * It is possible for one `FEDERATED' table to point to another, but
      you must be careful not to create a loop.
 
    * There is no support for transactions.
 
    * There is no way for the `FEDERATED' engine to know if the remote
      table has changed. The reason for this is that this table must
      work like a data file that would never be written to by anything
      other than the database. The integrity of the data in the local
      table could be breached if there was any change to the remote
      database.
 
    * The `FEDERATED' storage engine supports `SELECT', `INSERT',
      `UPDATE', `DELETE', and indexes. It does not support `ALTER TABLE',
      `DROP TABLE', or any other Data Definition Language statements.
      The current implementation does not use Prepared statements.
 
    * The implementation uses `SELECT', `INSERT', `UPDATE', and
      `DELETE', but not `HANDLER'.
 
    * `FEDERATED' tables do not work with the query cache.
 
 Some of these limitations may be lifted in future versions of the
 `FEDERATED' handler.
 

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