Syntax:
RESET MASTER

Deletes all binary log files listed in the index file, resets the
binary log index file to be empty, and creates a new binary log file.

In MySQL 5.6.5 and later, RESET MASTER also clears the values of the
gtid_purged system variable (known as gtid_lost in MySQL 5.6.8 and
earlier) as well as the global value of the gtid_executed (gtid_done,
prior to MySQL 5.6.9) system variable (but not its session value); that
is, executing this statement sets each of these values to an empty
string ('').

This statement is intended to be used only when the master is started
for the first time.

URL: http://dev.mysql.com/doc/refman/5.6/en/reset-master.html

