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MYSQLCHECK(1)                MySQL Database System               MYSQLCHECK(1)

       mysqlcheck - a table maintenance program

       mysqlcheck [options] [db_name [tbl_name ...]]

       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, although for
       check operations, the table is locked with a READ lock only (see Section 13.3.5, "LOCK TABLES and UNLOCK TABLES
       Syntax", for more information about READ and WRITE locks). 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 13.7.2, "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
           note     : The storage engine for the table doesn't support check

       If mysqlcheck is unable to repair a table, see Section 2.11.4, "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.

           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 [options] db_name [tbl_name ...]
           shell> mysqlcheck [options] --databases db_name ...
           shell> 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 names shown in the following table can be used to change mysqlcheck default behavior.

       |Command       | Meaning                          |
       |mysqlrepair   | The default option is --repair   |
       |mysqlanalyze  | The default option is --analyze  |
       |mysqloptimize | The default option is --optimize |

       mysqlcheck supports the following options, which can be specified on the command line or in the [mysqlcheck]
       and [client] groups of an option file. For information about option files used by MySQL programs, see
       Section 4.2.6, "Using Option Files".

       ?   --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, except that the INFORMATION_SCHEMA and performace_schema databases are not
           dumped. They can be dumped by explicitly naming them with the --databases option.

       ?   --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.

       ?   --auto-repair

           If a checked table is corrupted, automatically fix it. Any necessary repairs are done after all tables have
           been checked.

       ?   --bind-address=ip_address

           On a computer having multiple network interfaces, use this option to select which interface to use for
           connecting to the MySQL server.

           This option is supported beginning with MySQL 5.6.1.

       ?   --character-sets-dir=dir_name

           The directory where character sets are installed. See Section 10.5, "Character Set Configuration".

       ?   --check, -c

           Check the tables for errors. This is the default operation.

       ?   --check-only-changed, -C

           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.

       ?   --compress

           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 any following names as table names. With this option, it treats all
           name arguments as database names.

           This option may be used to dump the INFORMATION_SCHEMA and performace_schema databases, which normally are
           not dumped even with the --all-databases option. (Also use the --skip-lock-tables option.)

       ?   --debug[=debug_options], -# [debug_options]

           Write a debugging log. A typical debug_options string is d:t:o,file_name. The default is d:t:o.

       ?   --debug-check

           Print some debugging information when the program exits.

       ?   --debug-info

           Print debugging information and memory and CPU usage statistics when the program exits.

       ?   --default-character-set=charset_name

           Use charset_name as the default character set. See Section 10.5, "Character Set Configuration".

       ?   --defaults-extra-file=file_name

           Read this option file after the global option file but (on Unix) before the user option file. If the file
           does not exist or is otherwise inaccessible, an error occurs.  file_name is interpreted relative to the
           current directory if given as a relative path name rather than a full path name.

       ?   --defaults-file=file_name

           Use only the given option file. If the file does not exist or is otherwise inaccessible, an error occurs.
           file_name is interpreted relative to the current directory if given as a relative path name rather than a
           full path name.

       ?   --defaults-group-suffix=str

           Read not only the usual option groups, but also groups with the usual names and a suffix of str. For
           example, mysqlcheck normally reads the [client] and [mysqlcheck] groups. If the
           --defaults-group-suffix=_other option is given, mysqlcheck also reads the [client_other] and
           [mysqlcheck_other] groups.

       ?   --extended, -e

           If you are using this option to check tables, it ensures that they are 100% consistent but takes a long

           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!

       ?   --default-auth=plugin

           A hint about the client-side authentication plugin to use. See Section 6.3.7, "Pluggable Authentication".

           This option was added in MySQL 5.6.2.

       ?   --enable-cleartext-plugin

           Enable the mysql_clear_password cleartext authentication plugin. (See Section, "The Cleartext
           Client-Side Authentication Plugin".)

           This option was added in MySQL 5.6.28.

       ?   --fast, -F

           Check only tables that have not been closed properly.

       ?   --fix-db-names

           Convert database names to 5.1 format. Only database names that contain special characters are affected.

       ?   --fix-table-names

           Convert table names to 5.1 format. Only table names that contain special characters are affected. 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.

       ?   --login-path=name

           Read options from the named login path in the .mylogin.cnf login path file. A "login path" is an option
           group containing options that specify which MySQL server to connect to and which account to authenticate
           as. To create or modify a login path file, use the mysql_config_editor utility. See mysql_config_editor(1).
           This option was added in MySQL 5.6.6.

       ?   --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.

       ?   --no-defaults

           Do not read any option files. If program startup fails due to reading unknown options from an option file,
           --no-defaults can be used to prevent them from being read.

           The exception is that the .mylogin.cnf file, if it exists, is read in all cases. This permits passwords to
           be specified in a safer way than on the command line even when --no-defaults is used. (.mylogin.cnf is
           created by the mysql_config_editor utility. See mysql_config_editor(1).)

       ?   --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, mysqlcheck prompts for one.

           Specifying a password on the command line should be considered insecure. See Section, "End-User
           Guidelines for Password Security". You can use an option file to avoid giving the password on the command

       ?   --pipe, -W

           On Windows, connect to the server using a named pipe. This option applies only if the server supports
           named-pipe connections.

       ?   --plugin-dir=dir_name

           The directory in which to look for plugins. Specify this option if the --default-auth option is used to
           specify an authentication plugin but mysqlcheck does not find it. See Section 6.3.7, "Pluggable

           This option was added in MySQL 5.6.2.

       ?   --port=port_num, -P port_num

           The TCP/IP port number to use for the connection.

       ?   --print-defaults

           Print the program name and all options that it gets from option files.

       ?   --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
           permissible 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.

       ?   --secure-auth

           Do not send passwords to the server in old (pre-4.1) format. This prevents connections except for servers
           that use the newer password format. This option is enabled by default; use --skip-secure-auth to disable
           it. This option was added in MySQL 5.6.17.

               Passwords that use the pre-4.1 hashing method are less secure than passwords that use the native
               password hashing method and should be avoided. Pre-4.1 passwords are deprecated and support for them
               will be removed in a future MySQL release. For account upgrade instructions, see Section,
               "Migrating Away from Pre-4.1 Password Hashing and the mysql_old_password Plugin".

       ?   --shared-memory-base-name=name

           On Windows, the shared-memory name to use, for connections made using shared memory to a local server. The
           default value is MYSQL. The shared-memory name is case sensitive.

           The server must be started with the --shared-memory option to enable shared-memory connections.

       ?   --silent, -s

           Silent mode. Print only error messages.

       ?   --skip-database=db_name

           Do not include the named database (case sensitive) in the operations performed by mysqlcheck. This option
           was added in MySQL 5.6.11.

       ?   --socket=path, -S path

           For connections to localhost, the Unix socket file to use, or, on Windows, the name of the named pipe to

       ?   --ssl*

           Options that begin with --ssl specify whether to connect to the server using SSL and indicate where to find
           SSL keys and certificates. See Section 6.4.5, "Command Options for Secure Connections".

       ?   --tables

           Override the --databases or -B option. All name arguments following the option are regarded as table names.

       ?   --use-frm

           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.

       ?   --write-binlog

           This option is enabled by default, so that ANALYZE TABLE, OPTIMIZE TABLE, and REPAIR TABLE statements
           generated by mysqlcheck are written to the binary log. Use --skip-write-binlog to cause NO_WRITE_TO_BINLOG
           to be added to the statements so that they are not logged. Use the --skip-write-binlog when these
           statements should not be sent to replication slaves or run when using the binary logs for recovery from

       Copyright (C) 1997, 2016, Oracle and/or its affiliates. All rights reserved.

       This documentation is free software; you can redistribute it and/or modify it only under the terms of the GNU
       General Public License as published by the Free Software Foundation; version 2 of the License.

       This documentation is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
       the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
       for more details.

       You should have received a copy of the GNU General Public License along with the program; if not, write to the
       Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or see

       For more information, please refer to the MySQL Reference Manual, which may already be installed locally and
       which is also available online at

       Oracle Corporation (

MySQL 5.6                         07/08/2016                     MYSQLCHECK(1)