MySQL in a Nutshell, 2nd Edition

Name

REPAIR TABLE

Synopsis

REPAIR [LOCAL|NO_WRITE_TO_BINLOG] TABLE
    table[, ...] [QUICK] [EXTENDED] [USE_FRM]

Use this statement to repair corrupted MyISAM tables. Multiple tables may be given in a comma-separated list. To prevent this statement from recording its activities in the binary log file, give the NO_WRITE_TO_BINLOG keyword or its LOCAL alias. The QUICK keyword instructs MySQL to repair the table indexes only. The EXTENDED keyword rebuilds the indexes one row at a time. This option takes longer, but it can be more effective, especially with rows containing duplicate keys.

Before running this statement, make a backup of the table. If a table continues to have problems, there may be other problems (e.g., filesystem problems) that you should consider. Here is an example of this statement:

REPAIR TABLE systems QUICK EXTENDED;

+----------------------+--------+----------+----------+
| Table                | Op     | Msg_type | Msg_text |
+----------------------+--------+----------+----------+
| workrequests.systems | repair | status   | OK       |
+----------------------+--------+----------+----------+

In this example, the repair is successful. This is indicated by the OK in the Msg_text field. If it is unsuccessful, you could try the USE_FRM option with this statement. That option will create a new index file (.MYI) using the table schema file (.frm). It won’t be able to determine the current value for AUTO_INCREMENT columns or for DELETE LINK, so it shouldn’t be used unless the original .MYI file is lost. ...