Managing & Using MySQL, 2nd Edition

Name

FLUSH

Syntax

FLUSH option[, option...]

Description

Flushes or resets various internal processes depending on the options given. You must have RELOAD privileges to execute this statement. The option can be any of the following:

DES_KEY_FILE

Reloads the DES keys from the file originally specified with the --des-key-file option.

HOSTS

Empties the cache table that stores hostname information for clients. This should be used if a client changes IP addresses, or if there are errors related to connecting to the host.

LOGS

Closes all the standard log files and reopens them. This can be used if a log file has changed its inode number. If no specific extension has been given to the update log, a new update log will be opened with the extension incremented by one.

PRIVILEGES

Reloads all the internal MySQL permissions grant tables. This must be run for any changes to the tables to take effect.

QUERY CACHE

For better memory use, this command defragments the query cache but it does not delete queries from the cache.

STATUS

Resets the status variables that keep track of the current state of the server.

TABLE table TABLES table , table2 , ..., tablen

Flushes only the specified tables.

TABLES [WITH READ LOCK]

Closes all currently open tables and flushes any cached data to disk. With a read lock, it acquires a read lock that will not be released until UNLOCK TABLES is issued.