6.6.4.2 myisamchk Check Options

myisamchk supports the following options for table checking operations:

• --check, -c

  Command-Line Format	--check

  Check the table for errors. This is the default operation if you specify no option that selects an operation type explicitly.

• --check-only-changed, -C

  Command-Line Format	--check-only-changed

  Check only tables that have changed since the last check.

• --extend-check, -e

  Command-Line Format	--extend-check

  Check the table very thoroughly. This is quite slow if the table has many indexes. This option should only be used in extreme cases. Normally, myisamchk or myisamchk --medium-check should be able to determine whether there are any errors in the table.

  If you are using --extend-check and have plenty of memory, setting the key_buffer_size variable to a large value helps the repair operation run faster.

  See also the description of this option under table repair options.

  For a description of the output format, see Section 6.6.4.5, “Obtaining Table Information with myisamchk”.

• --fast, -F

  Command-Line Format	--fast

  Check only tables that haven't been closed properly.

• --force, -f

  Command-Line Format	--force

  Do a repair operation automatically if myisamchk finds any errors in the table. The repair type is the same as that specified with the --recover or -r option.

• --information, -i

  Command-Line Format	--information

  Print informational statistics about the table that is checked.

• --medium-check, -m

  Command-Line Format	--medium-check

  Do a check that is faster than an --extend-check operation. This finds only 99.99% of all errors, which should be good enough in most cases.

• --read-only, -T

  Command-Line Format	--read-only

  Do not mark the table as checked. This is useful if you use myisamchk to check a table that is in use by some other application that does not use locking, such as mysqld when run with external locking disabled.

• --update-state, -U

  Command-Line Format	--update-state

  Store information in the .MYI file to indicate when the table was checked and whether the table crashed. This should be used to get full benefit of the --check-only-changed option, but you shouldn't use this option if the mysqld server is using the table and you are running it with external locking disabled.