mysql5.6设置主从报错1236，Increase max_allowed_packet on master，原因却是Binlog偏移量不对

在试Mysql5.6，搭了个主从：

CHANGE MASTER TO                                                                                                                        
MASTER_HOST='1.2.3.4',                                                                                                                    
master_user='slave',        
master_password='xxxqqq',
master_port=5615,
MASTER_LOG_FILE='binlog.000001',
MASTER_LOG_POS=107;

一切正常。然后在主上建个表，在从上一看没有。再看看状态：

mysql> show slave status\G;
*************************** 1. row ***************************
               Slave_IO_State: 
                  Master_Host: 1.2.3.4
                  Master_User: slave
                  Master_Port: 5615
                Connect_Retry: 60
              Master_Log_File: binlog.000001
          Read_Master_Log_Pos: 107
               Relay_Log_File: relaylog.000002
                Relay_Log_Pos: 280
        Relay_Master_Log_File: binlog.000001
             Slave_IO_Running: No
            Slave_SQL_Running: Yes
              Replicate_Do_DB: 
          Replicate_Ignore_DB: 
           Replicate_Do_Table: 
       Replicate_Ignore_Table: 
      Replicate_Wild_Do_Table: 
  Replicate_Wild_Ignore_Table: 
                   Last_Errno: 0
                   Last_Error: 
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 107
              Relay_Log_Space: 446
              Until_Condition: None
               Until_Log_File: 
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File: 
           Master_SSL_CA_Path: 
              Master_SSL_Cert: 
            Master_SSL_Cipher: 
               Master_SSL_Key: 
        Seconds_Behind_Master: NULL
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 1236
                Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: 'log event entry exceeded max_allowed_packet; Increase max_allowed_packet on master; the first event 'binlog.000001' at 107, the last event read from '/mnt/disk1/mysql_5615_binlog/binlog.000001' at 107, the last byte read from '/mnt/disk1/mysql_5615_binlog/binlog.000001' at 126.'
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 3801
                  Master_UUID: aa8bc3d4-81aa-11e3-9065-001517a25b3a
             Master_Info_File: /mnt/disk1/mysql_5615/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 140121 09:10:31
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: 
                Auto_Position: 0
1 row in set (0.00 sec)

ERROR: 
No query specified

确认了我的max_allowed_packet 是32M，太够了啊。搞了半天无果，后来搜了搜，发现了这个贴子（http://blog.chinaunix.net/uid-451-id-3087001.html），说是根本原因是偏移量不对。于是去主上看看：

mysqlbinlog binlog.000001
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;
/*!40019 SET @@session.max_insert_delayed_threads=0*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
DELIMITER /*!*/;
# at 4
#140121  8:45:29 server id 601  end_log_pos 120 CRC32 0xf881fb00        Start: binlog v 4, server v 5.6.15-debug-log created 140121  8:45:29 at startup
ROLLBACK/*!*/;
BINLOG '
KcPdUg9ZAgAAdAAAAHgAAAAAAAQANS42LjE1LWRlYnVnLWxvZwAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAApw91SEzgNAAgAEgAEBAQEEgAAXAAEGggAAAAICAgCAAAACgoKGRkAAQD7
gfg=
'/*!*/;
# at 120
#140121  8:45:30 server id 601  end_log_pos 328 CRC32 0x4763204a        Query   thread_id=2     exec_time=0     error_code=0

于是在从上重新change master to，把偏移量设成120，就一切正常了。

我之前搞Mysql5.5时一直是偏移量107的，到了现在5.6了变成了120，有趣。

另外也是头脑反应慢了些，其实在主上看状态时也应该能反应到的：

mysql> show binary logs;
+---------------+-----------+
| Log_name      | File_size |
+---------------+-----------+
| binlog.000001 |       560 |
| binlog.000002 |       372 |
| binlog.000003 |       120 |
+---------------+-----------+
3 rows in set (0.03 sec)