Syntax:
FLUSH [NO_WRITE_TO_BINLOG | LOCAL]
    flush_option [, flush_option] ...

The FLUSH statement has several variant forms that clear or reload
various internal caches, flush tables, or acquire locks. To execute
FLUSH, you must have the RELOAD privilege. Specific flush options might
require additional privileges, as described later.

By default, the server writes FLUSH statements to the binary log so
that they replicate to replication slaves. To suppress logging, specify
the optional NO_WRITE_TO_BINLOG keyword or its alias LOCAL.

*Note*:

FLUSH LOGS, FLUSH MASTER, FLUSH SLAVE, and FLUSH TABLES WITH READ LOCK
(with or without a table list) are not written to the binary log in any
case because they would cause problems if replicated to a slave.

Sending a SIGHUP signal to the server causes several flush operations
to occur that are similar to various forms of the FLUSH statement. See
http://dev.mysql.com/doc/refman/5.5/en/server-signal-response.html.

The FLUSH statement causes an implicit commit. See
http://dev.mysql.com/doc/refman/5.5/en/implicit-commit.html.

The RESET statement is similar to FLUSH. See [HELP RESET], for
information about using the RESET statement with replication.

URL: http://dev.mysql.com/doc/refman/5.5/en/flush.html

