MySQL Reference Manual :: 14.6.4 Limitations of the FEDERATED Storage Engine

In the first version, the remote server must be a MySQL server. Support by FEDERATED for other database engines may be 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. You know and have heard the screeching of audio feedback? You know what you see visually when you place two mirrors in front of each other, how the reflection continues for eternity? Well, need we say more?!

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 has to 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 first implementation does not use Prepared statements. It remains to be seen whether the limited subset of the client API for the server supports this capability.

The implementation uses SELECT, INSERT, UPDATE, DELETE and not HANDLER.

FEDERATED tables do not work with the query cache.