MySQL Replication Using GTID

Surprisingly, that's not gibberish.

That indeed appears at the top of binlogs whenever you do mysqlbinlog to a binary log generated using MySQL 5.1 and MySQL 5.5. You will not see that gibberish in binary logs for MySQL 5.0 and back.

This is why the start point for replication from an empty binary log is

• 107 for MySQL 5.5
• 106 for MySQL 5.1
• 98 for MySQL 5.0 and back

This is good to remember if you do MySQL Replication where the Master if MySQL 5.1 and the slave is MySQL 5.0. This could present a really big headache.

Replication from Master using 5.0 and Slave using 5.1 works fine, not the other way around.(According to MySQL Documentation, it is generally not supported for 3 reasons: 1) Binary Log Format, 2) Row-based Replication, 3) SQL Incompatibility).

Anyway, do a mysqlbinlog on the offending binary log on the master. If the resulting dump produces gibberish in the middle of the dump (which I have seen a couple of times in my DBA career) you may have to skip to position 98 (MySQL 5.0) or 106 (MySQL 5.1) or 107 (MySQL 5.5) of the master's next binary log and start replicating from there (SOB :( you may need to use MAATKIT tools mk-table-checksum and mk-table-sync to reload master changes not on the slave [if you want to be a hero]; even worse, mysqldump the master and reload the slave and start replication totally over [if you don't want to be a hero])

If the mysqlbinlog of the master is completely readable after the top gibberish you saw, it is possible the master's binary log is fine but the relay log on the slave is corrupt (due to transmission/CRC errors). If that's the case, just reload the relay logs by issuing the CHANGE MASTER TO command as follows:

STOP SLAVE;
CHANGE MASTER TO
MASTER_HOST='< master-host ip or DNS >',
MASTER_PORT=3306,
MASTER_USER='< usernmae >',
MASTER_PASSWORD='< password >',
MASTER_LOG_FILE='< MMMM >',
MASTER_LOG_POS=< PPPP >;
START SLAVE;

Where

• MMMM is the last file used from the Master that was last processed on the Slave
• PPPP is the last position used from the Master that was last processed on the Slave

You can get MMMM and PPPP by doing SHOW SLAVE STATUS\G and using

• Relay_Master_Log_File for MMMM
• Exec_Master_Log_Pos for PPPP

Try it out and let me know !!!

BTW running CHANGE MASTER TO command erases the slave's current relay logs and starts fresh.

Relay log rotation have nothing to do with it.

What's critical is that the slaves, if set up with log_slave_updates (i.e. in themselves logging to binary logs), are pre-configured with binlog_format = MIXED or binlog_format = ROW.

To elaborate: there is no problem if the master uses binlog_format = STATEMENT and the slaves use ROW. There is a problem if the master uses ROW and the slaves use STATEMENT. You just can't restore the exact original statement from ROW format.

Likewise, if you master is MIXED, then slaves must be wither MIXED or ROW.

Back to your question, assuming the slaves are already configured with MIXED, there is no problem in just SET GLOBAL binlog_format = MIXED on the master. There is no problem in the binary log containing some entries of this format and some entries of the other. There is no problem with the relay logs containing entries of both forms.

I disagree with the accepted answer you linked to.