Syntax:
RESET SLAVE [ALL]

RESET SLAVE makes the slave forget its replication position in the
master's binary log. This statement is meant to be used for a clean
start: It clears the master info and relay log info repositories,
deletes all the relay log files, and starts a new relay log file. It
also resets to 0 the replication delay specified with the MASTER_DELAY
option to CHANGE MASTER TO. To use RESET SLAVE, the slave replication
threads must be stopped (use STOP SLAVE if necessary).

*Note*: All relay log files are deleted, even if they have not been
completely executed by the slave SQL thread. (This is a condition
likely to exist on a replication slave if you have issued a STOP SLAVE
statement or if the slave is highly loaded.)

In MySQL 5.6 (unlike the case in MySQL 5.1 and earlier), RESET SLAVE
does not change any replication connection parameters such as master
host, master port, master user, or master password, which are retained
in memory. This means that START SLAVE can be issued without requiring
a CHANGE MASTER TO statement following RESET SLAVE.

Connection parameters are reset if the slave mysqld is shut down
following RESET SLAVE. In MySQL 5.6.3 and later, you can instead use
RESET SLAVE ALL to reset these connection parameters (Bug #11809016).

RESET SLAVE ALL does not clear the IGNORE_SERVER_IDS list set by CHANGE
MASTER TO. This issue is fixed in MySQL 5.7. (Bug #18816897)

In MySQL 5.6.7 and later, RESET SLAVE causes an implicit commit of an
ongoing transaction. See
http://dev.mysql.com/doc/refman/5.6/en/implicit-commit.html.

If the slave SQL thread was in the middle of replicating temporary
tables when it was stopped, and RESET SLAVE is issued, these replicated
temporary tables are deleted on the slave.

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

