"Federared Transactions Failure"
  Bug occurs when the user performs an operation which inserts more than 
  one row into the federated table and the federated table references a 
  remote table stored within a transactional storage engine. When the
  insert operation for any one row in the statement fails due to 
  constraint violation, the federated engine is unable to perform 
  statement rollback and so the remote table contains a partial commit. 
  The user would expect a statement to perform the same so a statement 
  rollback is expected.
  This bug was fixed by implementing  bulk-insert handling into the
  federated storage engine. This will relieve the bug for most common
  situations by enabling the generation of a multi-row insert into the
  remote table and thus permitting the remote table to perform 
  statement rollback when neccessary.
  The multi-row insert is limited to the maximum packet size between 
  servers and should the size overflow, more than one insert statement 
  will be sent and this bug will reappear. Multi-row insert is disabled
  when an "INSERT...ON DUPLICATE KEY UPDATE" is being performed.
  The bulk-insert handling will offer a significant performance boost 
  when inserting a large number of small rows.
This patch builds on Bug29019 and Bug25511