Syntax:
FLUSH [NO_WRITE_TO_BINLOG | LOCAL] {
    flush_option [, flush_option] ...
  | tables_option
}

flush_option: {
    BINARY LOGS
  | DES_KEY_FILE
  | ENGINE LOGS
  | ERROR LOGS
  | GENERAL LOGS
  | HOSTS
  | LOGS
  | MASTER
  | PRIVILEGES
  | QUERY CACHE
  | RELAY LOGS
  | SLAVE
  | SLOW LOGS
  | STATUS
  | USER_RESOURCES
}

tables_option: {
    TABLES
  | TABLES tbl_name [, tbl_name] ...
  | TABLES WITH READ LOCK
  | TABLES tbl_name [, tbl_name] ... WITH READ LOCK
}

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.

*Note*:

It is not possible to issue FLUSH statements within stored functions or
triggers. However, you may use FLUSH in stored procedures, so long as
these are not called from stored functions or triggers. See
http://dev.mysql.com/doc/refman/5.5/en/stored-program-restrictions.html
.

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.

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

The mysqladmin utility provides a command-line interface to some flush
operations, using commands such as flush-hosts, flush-logs,
flush-privileges, flush-status, and flush-tables. See
http://dev.mysql.com/doc/refman/5.5/en/mysqladmin.html.

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 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

