Original revision:
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revision-id: li-bing.song@sun.com-20100130124925-o6sfex42b6noyc6x
parent: joro@sun.com-20100129145427-0n79l9hnk0q43ajk
committer: <Li-Bing.Song@sun.com>
branch nick: mysql-5.1-bugteam
timestamp: Sat 2010-01-30 20:49:25 +0800
message:
  Bug #48321  CURRENT_USER() incorrectly replicated for DROP/RENAME USER;
              REVOKE/GRANT; ALTER EVENT.
  
  The following statements support the CURRENT_USER() where a user is needed.
    DROP USER 
    RENAME USER CURRENT_USER() ...
    GRANT ... TO CURRENT_USER()
    REVOKE ... FROM CURRENT_USER()
    ALTER DEFINER = CURRENT_USER() EVENT
  but, When these statements are binlogged, CURRENT_USER() just is binlogged
  as 'CURRENT_USER()', it is not expanded to the real user name. When slave 
  executes the log event, 'CURRENT_USER()' is expand to the user of slave 
  SQL thread, but SQL thread's user name always NULL. This breaks the replication.
  
  After this patch, All above statements are rewritten when they are binlogged.
  The CURRENT_USER() is expanded to the real user's name and host.
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