The mysqlcheck client performs table maintenance: It checks, repairs, optimizes, or analyzes tables.
        Each table is locked and therefore unavailable to other sessions
        while it is being processed. Table maintenance operations can be
        time-consuming, particularly for large tables. If you use the
        --databases or
        --all-databases option to
        process all tables in one or more databases, an invocation of
        mysqlcheck might take a long time. (This is
        also true for mysql_upgrade because that
        program invokes mysqlcheck to check all
        tables and repair them if necessary.)
      
mysqlcheck is similar in function to myisamchk, but works differently. The main operational difference is that mysqlcheck must be used when the mysqld server is running, whereas myisamchk should be used when it is not. The benefit of using mysqlcheck is that you do not have to stop the server to perform table maintenance.
        mysqlcheck uses the SQL statements
        CHECK TABLE,
        REPAIR TABLE,
        ANALYZE TABLE, and
        OPTIMIZE TABLE in a convenient
        way for the user. It determines which statements to use for the
        operation you want to perform, and then sends the statements to
        the server to be executed. For details about which storage
        engines each statement works with, see the descriptions for
        those statements in Section 12.5.2, “Table Maintenance Statements”.
      
        The MyISAM storage engine supports all four
        maintenance operations, so mysqlcheck can be
        used to perform any of them on MyISAM tables.
        Other storage engines do not necessarily support all operations.
        In such cases, an error message is displayed. For example, if
        test.t is a MEMORY table,
        an attempt to check it produces this result:
      
shell> mysqlcheck test t
test.t
note     : The storage engine for the table doesn't support check
        If mysqlcheck is unable to repair a table,
        see Section 2.12.4, “Rebuilding or Repairing Tables or Indexes” for manual table repair
        strategies. This will be the case, for example, for
        InnoDB tables, which can be checked with
        CHECK TABLE, but not repaired
        with REPAIR TABLE.
      
The use of mysqlcheck with partitioned tables is not supported before MySQL 5.1.27.
It is best to make a backup of a table before performing a table repair operation; under some circumstances the operation might cause data loss. Possible causes include but are not limited to file system errors.
There are three general ways to invoke mysqlcheck:
shell>mysqlcheck [shell>options]db_name[tables]mysqlcheck [shell>options] --databasesdb_name1[db_name2db_name3...]mysqlcheck [options] --all-databases
        If you do not name any tables following
        db_name or if you use the
        --databases or
        --all-databases option,
        entire databases are checked.
      
        mysqlcheck has a special feature compared to
        other client programs. The default behavior of checking tables
        (--check) can be changed by
        renaming the binary. If you want to have a tool that repairs
        tables by default, you should just make a copy of
        mysqlcheck named
        mysqlrepair, or make a symbolic link to
        mysqlcheck named
        mysqlrepair. If you invoke
        mysqlrepair, it repairs tables.
      
The following names can be used to change mysqlcheck default behavior.
| mysqlrepair | The default option is --repair | 
| mysqlanalyze | The default option is --analyze | 
| mysqloptimize | The default option is --optimize | 
Table 4.4. mysqlcheck Options
| Format | Config File | Description | Introduction | Deprecated | Removed | 
|---|---|---|---|---|---|
| --all-databases | all-databases | Check all tables in all databases | |||
| --all-in-1 | all-in-1 | Execute a single statement for each database that names all the tables from that database | |||
| --analyze | analyze | Analyze the tables | |||
| --auto-repair | auto-repair | If a checked table is corrupted, automatically fix it | |||
| --character-sets-dir=path | character-sets-dir | The directory where character sets are installed | |||
| --check | check | Check the tables for errors | |||
| --check-only-changed | check-only-changed | Check only tables that have changed since the last check | |||
| --check-upgrade | check-upgrade | Invoke CHECK TABLE with the FOR UPGRADE option | 5.1.7 | ||
| --compress | compress | Compress all information sent between the client and the server | |||
| --databases | databases | Process all tables in the named databases | |||
| --debug[=debug_options] | debug | Write a debugging log | |||
| --debug-check | debug-check | Print debugging information when the program exits | 5.1.21 | ||
| --debug-info | debug-info | Print debugging information, memory and CPU statistics when the program exits | 5.1.14 | ||
| --default-character-set=charset_name | default-character-set | Use charset_name as the default character set | |||
| --extended | extended | Check and repair tables | |||
| --fast | fast | Check only tables that have not been closed properly | |||
| --fix-db-names | fix-db-names | Convert database names to 5.1 format | 5.1.7 | ||
| --fix-table-names | fix-table-names | Convert table names to 5.1 format | 5.1.7 | ||
| --force | force | Continue even if an SQL error occurs | |||
| --help | Display help message and exit | ||||
| --host=host_name | host | Connect to the MySQL server on the given host | |||
| --medium-check | medium-check | Do a check that is faster than an --extended operation | |||
| --optimize | optimize | Optimize the tables | |||
| --password[=password] | password | The password to use when connecting to the server | |||
| --pipe | On Windows, connect to server via a named pipe | ||||
| --port=port_num | port | The TCP/IP port number to use for the connection | |||
| --protocol=type | protocol | The connection protocol to use | |||
| --quick | quick | The fastest method of checking | |||
| --repair | repair | Perform a repair that can fix almost anything except unique keys that are not unique | |||
| --silent | silent | Silent mode | |||
| --socket=path | socket | For connections to localhost | |||
| --ssl-ca=file_name | ssl-ca | The path to a file that contains a list of trusted SSL CAs | |||
| --ssl-capath=directory_name | ssl-capath | The path to a directory that contains trusted SSL CA certificates in PEM format | |||
| --ssl-cert=file_name | ssl-cert | The name of the SSL certificate file to use for establishing a secure connection | |||
| --ssl-cipher=cipher_list | ssl-cipher | A list of allowable ciphers to use for SSL encryption | |||
| --ssl-key=file_name | ssl-key | The name of the SSL key file to use for establishing a secure connection | |||
| --ssl-verify-server-cert | ssl-verify-server-cert | The server's Common Name value in its certificate is verified against the host name used when connecting to the server | |||
| --tables | tables | Overrides the --databases or -B option | |||
| --use-frm | use-frm | For repair operations on MyISAM tables | |||
| --user=user_name, | user | The MySQL user name to use when connecting to the server | |||
| --verbose | Verbose mode | ||||
| --version | Display version information and exit | 
mysqlcheck supports the options in the following list. It also reads option files and supports the options for processing them described at Section 4.2.3.3.1, “Command-Line Options that Affect Option-File Handling”.
            
            
            --help,
            -?
          
Display a help message and exit.
            
            
            --all-databases,
            -A
          
            Check all tables in all databases. This is the same as using
            the --databases option
            and naming all the databases on the command line.
          
            
            
            --all-in-1,
            -1
          
Instead of issuing a statement for each table, execute a single statement for each database that names all the tables from that database to be processed.
            
            
            --analyze,
            -a
          
Analyze the tables.
MySQL Enterprise. For expert advice on optimizing tables, subscribe to the MySQL Enterprise Monitor. For more information, see http://www.mysql.com/products/enterprise/advisors.html.
If a checked table is corrupted, automatically fix it. Any necessary repairs are done after all tables have been checked.
The directory where character sets are installed. See Section 9.2, “The Character Set Used for Data and Sorting”.
            
            
            --check,
            -c
          
Check the tables for errors. This is the default operation.
Check only tables that have changed since the last check or that have not been closed properly.
            
            
            --check-upgrade,
            -g
          
            Invoke CHECK TABLE with the
            FOR UPGRADE option to check tables for
            incompatibilities with the current version of the server.
            This option automatically enables the
            --fix-db-names and
            --fix-table-names
            options. --check-upgrade
            was added in MySQL 5.1.7.
          
Compress all information sent between the client and the server if both support compression.
            
            
            --databases,
            -B
          
Process all tables in the named databases. Normally, mysqlcheck treats the first name argument on the command line as a database name and following names as table names. With this option, it treats all name arguments as database names.
            
            
            --debug[=,
            debug_options]-#
            [
          debug_options]
            Write a debugging log. A typical
            debug_options string is
            'd:t:o,.
            The default is file_name''d:t:o'.
          
Print some debugging information when the program exits. This option was added in MySQL 5.1.21.
Print debugging information and memory and CPU usage statistics when the program exits. This option was added in MySQL 5.1.14.
            
            
            --default-character-set=
          charset_name
            Use charset_name as the default
            character set. See Section 9.2, “The Character Set Used for Data and Sorting”.
          
            
            
            --extended,
            -e
          
If you are using this option to check tables, it ensures that they are 100% consistent but takes a long time.
If you are using this option to repair tables, it runs an extended repair that may not only take a long time to execute, but may produce a lot of garbage rows also!
            
            
            --fast,
            -F
          
Check only tables that have not been closed properly.
Convert database names to 5.1 format. Only database names that contain special characters are affected. This option was added in MySQL 5.1.7.
Convert table names to 5.1 format. Only table names that contain special characters are affected. This option was added in MySQL 5.1.7. As of MySQL 5.1.23, this option also applies to views.
            
            
            --force,
            -f
          
Continue even if an SQL error occurs.
            
            
            --host=,
            host_name-h 
          host_name
Connect to the MySQL server on the given host.
            
            
            --medium-check,
            -m
          
            Do a check that is faster than an
            --extended operation.
            This finds only 99.99% of all errors, which should be good
            enough in most cases.
          
            
            
            --optimize,
            -o
          
Optimize the tables.
            
            
            --password[=,
            password]-p[
          password]
            The password to use when connecting to the server. If you
            use the short option form (-p), you
            cannot have a space between the option
            and the password. If you omit the
            password value following the
            --password or
            -p option on the command line, you are
            prompted for one.
          
Specifying a password on the command line should be considered insecure. See Section 5.5.6.2, “End-User Guidelines for Password Security”.
            
            
            --pipe,
            -W
          
On Windows, connect to the server via a named pipe. This option applies only for connections to a local server, and only if the server supports named-pipe connections.
            
            
            --port=,
            port_num-P 
          port_num
The TCP/IP port number to use for the connection.
            
            
            --protocol={TCP|SOCKET|PIPE|MEMORY}
          
The connection protocol to use for connecting to the server. It is useful when the other connection parameters normally would cause a protocol to be used other than the one you want. For details on the allowable values, see Section 4.2.2, “Connecting to the MySQL Server”.
            
            
            --quick,
            -q
          
If you are using this option to check tables, it prevents the check from scanning the rows to check for incorrect links. This is the fastest check method.
If you are using this option to repair tables, it tries to repair only the index tree. This is the fastest repair method.
            
            
            --repair,
            -r
          
Perform a repair that can fix almost anything except unique keys that are not unique.
            
            
            --silent,
            -s
          
Silent mode. Print only error messages.
            
            
            --socket=,
            path-S 
          path
            For connections to localhost, the Unix
            socket file to use, or, on Windows, the name of the named
            pipe to use.
          
            Options that begin with
            --ssl specify whether to
            connect to the server via SSL and indicate where to find SSL
            keys and certificates. See Section 5.5.7.3, “SSL Command Options”.
          
            Override the --databases
            or -B option. All name arguments following
            the option are regarded as table names.
          
            For repair operations on MyISAM tables,
            get the table structure from the .frm
            file so that the table can be repaired even if the
            .MYI header is corrupted.
          
            
            
            --user=,
            user_name-u 
          user_name
The MySQL user name to use when connecting to the server.
            
            
            --verbose,
            -v
          
Verbose mode. Print information about the various stages of program operation.
            
            
            --version,
            -V
          
Display version information and exit.


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