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=,
MASTER_LOG_FILE='binlog.000001',
MASTER_LOG_POS=;

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;
*************************** . row ***************************
               Slave_IO_State:
                  Master_Host: 1.2.3.4
                  Master_User: slave
                  Master_Port:
                Connect_Retry:
              Master_Log_File: binlog.
          Read_Master_Log_Pos:
               Relay_Log_File: relaylog.
                Relay_Log_Pos:
        Relay_Master_Log_File: binlog.
             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:
                   Last_Error:
                 Skip_Counter:
          Exec_Master_Log_Pos:
              Relay_Log_Space:
              Until_Condition: None
               Until_Log_File:
                Until_Log_Pos:
           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:
                Last_IO_Error: Got fatal error  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.' at 107, the last event read from '/mnt/disk1/mysql_5615_binlog/binlog.' at 107, the last byte read from '/mnt/disk1/mysql_5615_binlog/binlog.' at 126.'
               Last_SQL_Errno:
               Last_SQL_Error:
  Replicate_Ignore_Server_Ids:
             Master_Server_Id:
                  Master_UUID: aa8bc3d4-81aa-11e3--001517a25b3a
             Master_Info_File: /mnt/disk1/mysql_5615/master.info
                    SQL_Delay:
          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:
                  Master_Bind:
      Last_IO_Error_Timestamp:  ::
     Last_SQL_Error_Timestamp:
               Master_SSL_Crl:
           Master_SSL_Crlpath:
           Retrieved_Gtid_Set:
            Executed_Gtid_Set:
                Auto_Position:
 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.
/*!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
#  :: server id   end_log_pos  CRC32 0xf881fb00        Start: binlog v , server v 5.6.-debug-log created   :: at startup
ROLLBACK/*!*/;
BINLOG '
KcPdUg9ZAgAAdAAAAHgAAAAAAAQANS42LjE1LWRlYnVnLWxvZwAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAApw91SEzgNAAgAEgAEBAQEEgAAXAAEGggAAAAICAgCAAAACgoKGRkAAQD7
gfg=
'/*!*/;
# at
#  :: server id   end_log_pos  CRC32 0x4763204a        Query   thread_id=     exec_time=     error_code=

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. |        |
| binlog. |        |
| binlog. |        |
+---------------+-----------+
 rows in set (0.03 sec)