Name
OPTIMIZE TABLE
Synopsis
OPTIMIZE [LOCAL|NO_WRITE_TO_BINLOG] TABLE table
[, . . . ]
Use this statement to optimize the
data contained in a table. Optimization is useful when many rows have
been deleted from a table. It’s also useful to run
this statement periodically with a table that contains several
variable-character-width columns (i.e., VARCHAR
,
BLOB
, and TEXT
columns). This
statement generally works only with MyISAM, BDB, and InnoDB tables.
It may work on other tables, however, if the
mysqld daemon is started with the
--skip-new
option or the
--safe-mode
option. See Chapter 10 for more information on setting server
startup options.
This statement will repair some row
problems and sort indexes. It will temporarily lock the tables
involved while optimizing. Multiple tables can be listed for
optimization in a comma-separated list. To prevent the activities of
this statement from being recorded in the binary log file, use the
NO_WRITE_TO_BINLOG
flag or its alias,
LOCAL
. Here is an example of its use:
OPTIMIZE LOCAL TABLE workreq, clients; +----------------------+----------+----------+----------+ | Table | Op | Msg_type | Msg_text | +----------------------+----------+----------+----------+ | workrequests.workreq | optimize | status | OK | | workrequests.clients | optimize | status | OK | +----------------------+----------+----------+----------+
Here two tables were optimized successfully and the activity was not written to the binary log file.
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