This section discusses how to use myisamchk to check or repair MyISAM tables (tables that have .MYD and .MYI files for storing data and indexes). For general myisamchk background, see Section 8.2, “myisamchk — MyISAM Table-Maintenance Utility”.

You can use myisamchk to get information about your database tables or to check, repair, or optimize them. The following sections describe how to perform these operations and how to set up a table maintenance schedule.

Even though table repair with myisamchk is quite secure, it is always a good idea to make a backup before doing a repair or any maintenance operation that could make a lot of changes to a table

myisamchk operations that affect indexes can cause FULLTEXT indexes to be rebuilt with full-text parameters that are incompatible with the values used by the MySQL server. To avoid this problem, follow the guidelines in Section 8.2.1, “myisamchk General Options”.

In many cases, you may find it simpler to do MyISAM table maintenance using the SQL statements that perform operations that myisamchk can do:

These statements can be used directly or by means of the mysqlcheck client program. One advantage of these statements over myisamchk is that the server does all the work. With myisamchk, you must make sure that the server does not use the tables at the same time so that there is no unwanted interaction between myisamchk and the server. See Section 13.5.2.1, “ANALYZE TABLE Syntax”, Section 13.5.2.3, “CHECK TABLE Syntax”, Section 13.5.2.5, “OPTIMIZE TABLE Syntax”, and Section 13.5.2.6, “REPAIR TABLE Syntax”.