myisamchk supports the following options for table checking
operations:
• --check, -c
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
Check only tables that have changed since the last check.
• --extend-check, -e
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.
For a description of the output format, see the section
called 'MYISAMCHK TABLE INFORMATION'.
• --fast, -F
Check only tables that haven´t been closed properly.
• --force, -f
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. States will be
updated as with --update-state.
• --information, -i
Print informational statistics about the table that is
checked.
• --medium-check, -m
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
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
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.
