SQL Thread Error : Could not parse relay log event entry.

What problems ??

When you use MySQL replication, you may see replication errors :

 Relay log read failure: Could not parse relay log event entry. The possible reasons are: the master's binary log is corrupted (you can check this by running 'mysqlbinlog' on the binary log), the slave's relay log is corrupted (you can check this by running 'mysqlbinlog' on the relay log), a network problem, or a bug in the master's or slave's MySQL code. If you want to check the master's binary log or slave's relay log, you will be able to know their names by issuing 'SHOW SLAVE STATUS' on this slave. 

Then, SQL thread stop running.

What for ?

1. The relay log is corrupted is corrupted for any reason.
2. for network problems
3. The master's binary log is corrupted for any reason.

You can check relay log by running 'mysqlbinlog'

What Can I do for fixing problems?

1. STOP SLAVE;
2. SHOW SLAVE STATUS;==> Checking Relay_Master_Log_File, Exec_Master_Log_Pos
3. RESET SLAVE;
4. CHANGE MASTER TO
    MASTER_HOST = 'xxx',
    MASTER_PORT=3306,
    MASTER_USER='xx',
    MASTER_PASSWORD='xxx',
    MASTER_LOG_FILE='Relay_Master_Log_File's VALUE',
    MASTER_LOG_POS='Exec_Master_Log_Pos's VALUE';
5. START SLAVE;