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(mysql.info)Using mysqlcheck

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Using `mysqlcheck' for Table Maintenance and Crash Recovery
-----------------------------------------------------------

Since MySQL version 3.23.38 you will be able to use a new checking and
repairing tool for `MyISAM' tables. The difference to `myisamchk' is
that `mysqlcheck' should be used when the `mysqld' server is running,
where as `myisamchk' should be used when it is not. The benefit is that
you no longer have to take the server down for checking or repairing
your tables.

`mysqlcheck' uses MySQL server commands `CHECK', `REPAIR', `ANALYZE'
and `OPTIMIZE' in a convenient way for the user.

There are three alternative ways to invoke `mysqlcheck':

     shell> mysqlcheck [OPTIONS] database [tables]
     shell> mysqlcheck [OPTIONS] --databases DB1 [DB2 DB3...]
     shell> mysqlcheck [OPTIONS] --all-databases

So it can be used in a similar way as `mysqldump' when it comes to what
databases and tables you want to choose.

`mysqlcheck' does have a special feature compared to the other clients;
the default behavior, checking tables (-c), can be changed by renaming
the binary. So if you want to have a tool that repairs tables by
default, you should just copy `mysqlcheck' to your harddrive with a new
name, `mysqlrepair', or alternatively make a symbolic link to
`mysqlrepair' and name the symbolic link as `mysqlrepair'. If you
invoke `mysqlrepair' now, it will repair tables by default.

The names that you can use to change `mysqlcheck' default behavior are
here:

     mysqlrepair:   The default option will be -r
     mysqlanalyze:  The default option will be -a
     mysqloptimize: The default option will be -o

The options available for `mysqlcheck' are listed here, please check
what your version supports with `mysqlcheck --help'.

`-A, --all-databases'
     Check all the databases. This will be same as -databases with all
     databases selected

`-1, --all-in-1'
     Instead of making one query for each table, execute all queries in
     1 query separately for each database. Table names will be in a
     comma separated list.

`-a, --analyze'
     Analyze given tables.

`--auto-repair'
     If a checked table is corrupted, automatically fix it. Repairing
     will be done after all tables have been checked, if corrupted ones
     were found.

`-#, --debug=...'
     Output debug log. Often this is 'd:t:o,filename'

`--character-sets-dir=...'
     Directory where character sets are

`-c, --check'
     Check table for errors

`-C, --check-only-changed'
     Check only tables that have changed since last check or haven't
     been closed properly.

`--compress'
     Use compression in server/client protocol.

`-?, --help'
     Display this help message and exit.

`-B, --databases'
     To check several databases. Note the difference in usage; In this
     case no tables are given. All name arguments are regarded as
     database names.

`--default-character-set=...'
     Set the default character set

`-F, --fast'
     Check only tables that hasn't been closed properly

`-f, --force'
     Continue even if we get an sql-error.

`-e, --extended'
     If you are using this option with CHECK TABLE, it will ensure that
     the table is 100 percent consistent, but will take a long time.

     If you are using this option with REPAIR TABLE, it will run an
     extended repair on the table, which may not only take a long time
     to execute, but may produce a lot of garbage rows also!

`-h, --host=...'
     Connect to host.

`-m, --medium-check'
     Faster than extended-check, but only finds 99.99 percent of all
     errors. Should be good enough for most cases.

`-o, --optimize'
     Optimize table

`-p, --password[=...]'
     Password to use when connecting to server. If password is not given
     it's solicited on the tty.

`-P, --port=...'
     Port number to use for connection.

`-q, --quick'
     If you are using this option with CHECK TABLE, it prevents the
     check from scanning the rows to check for wrong links. This is the
     fastest check.

     If you are using this option with REPAIR TABLE, it will try to
     repair only the index tree. This is the fastest repair method for
     a table.

`-r, --repair'
     Can fix almost anything except unique keys that aren't unique.

`-s, --silent'
     Print only error messages.

`-S, --socket=...'
     Socket file to use for connection.

`--tables'
     Overrides option -databases (-B).

`-u, --user=#'
     User for login if not current user.

`-v, --verbose'
     Print info about the various stages.

`-V, --version'
     Output version information and exit.