replicate-rewrite-db

replicate-rewrite-db：

Tells the slave to translate the default database (that is, the one selected by USE) to to_name if it was from_name on the master. Only statements involving tables are affected (not statements such as CREATE DATABASE, DROP DATABASE, and ALTER DATABASE), and only if from_name is the default database on the master. This does not work for cross-database updates. To specify multiple rewrites, use this option multiple times. The server uses the first one with a from_name value that matches. The database name translation is done before the --replicate-* rules are tested.
If you use this option on the command line and the “>” character is special to your command interpreter, quote the option value. For example:
shell> mysqld --replicate-rewrite-db="olddb->newdb"

比如，master与slave同步fandb这个库，但因为需要slave需要将fandb改名为dudb，master不能改，就需要这个参数
在Slave端的my.cnf中加入
replicate-rewrite-db=fandb->dudb

重启Slave库，然后首先要创建dudb这个库

加入Master端执行

(mysql@localhost) [fandb]> create table rewrite as select * from ab;

如果Slave没有dudb.ab这个表，就会报错

[ERROR] Slave SQL: Error 'Table 'dudb.ab' doesn't exist' on query. Default database: 'dudb'. Query: 'create table rewrite as select * from ab', Error_code: 1146
2015-07-10 09:44:58 48962 [Warning] Slave: Table 'dudb.ab' doesn't exist Error_code: 1146
2015-07-10 09:44:58 48962 [ERROR] Error running query, slave SQL thread aborted. Fix the problem, and restart the slave SQL thread with "SLAVE START". We stopped at log 'mysql-bin.000003' position 3973

然后sql_thread也会被停止

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.134.132
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000003
          Read_Master_Log_Pos: 4089
               Relay_Log_File: mysql-relay-bin.000002
                Relay_Log_Pos: 283
        Relay_Master_Log_File: mysql-bin.000003
             Slave_IO_Running: Yes
            Slave_SQL_Running: No

这时需要手动create table dudb.ab as select * from fandb.ab

然后在start slave sql_thread

如果有多个库需要换名字，那么需要多次指定这个参数 

replicate-rewrite-db=fandb->dudb

replicate-rewrite-db=a->b