Provided by: mysql-client-core-5.7_5.7.23-2ubuntu1_amd64 bug

NAME

       mysqlcheck - a table maintenance program

SYNOPSIS

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

DESCRIPTION

       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 must be used when the mysqld server is running, which means 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”.

       All storage engines do not necessarily support all four maintenance operations. In such
       cases, an error message is displayed. For example, if test.t is an 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 2.11.3, “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.

           Caution
           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.

       ┌──────────────┬──────────────────────────────────┐
       │CommandMeaning                          │
       ├──────────────┼──────────────────────────────────┤
       │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 checked. They can be checked 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.

       ·   --character-sets-dir=dir_name

           The directory where character sets are installed. See Section 10.14, “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.

       ·   --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 10.14, “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.

           Exception: Even with --defaults-file, client programs read .mylogin.cnf.

       ·   --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 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!

       ·   --default-auth=plugin

           A hint about the client-side authentication plugin to use. See Section 6.3.9,
           “Pluggable Authentication”.

       ·   --enable-cleartext-plugin

           Enable the mysql_clear_password cleartext authentication plugin. (See Section 6.5.1.6,
           “Client-Side Cleartext Pluggable Authentication”.)

           This option was added in MySQL 5.7.10.

       ·   --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.

           This option is deprecated in MySQL 5.7.6 and will be removed in a future version of
           MySQL. If it is necessary to convert MySQL 5.0 database or table names, a workaround
           is to upgrade a MySQL 5.0 installation to MySQL 5.1 before upgrading to a more recent
           release.

       ·   --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.

           This option is deprecated in MySQL 5.7.6 and will be removed in a future version of
           MySQL. If it is necessary to convert MySQL 5.0 database or table names, a workaround
           is to upgrade a MySQL 5.0 installation to MySQL 5.1 before upgrading to a more recent
           release.

       ·   --force, -f

           Continue even if an SQL error occurs.

       ·   --get-server-public-key

           Request from the server the public key required for RSA key pair-based password
           exchange. This option applies to clients that that authenticate with the
           caching_sha2_password authentication plugin. For that plugin, the server does not send
           the public key unless requested. This option is ignored for accounts that do not
           authenticate with that plugin. It is also ignored if RSA-based password exchange is
           not used, as is the case when the client connects to the server using a secure
           connection.

           If --server-public-key-path=file_name is given and specifies a valid public key file,
           it takes precedence over --get-server-public-key.

           For information about the caching_sha2_password plugin, see Section 6.5.1.5, “Caching
           SHA-2 Pluggable Authentication”.

           The --get-server-public-key option was added in MySQL 5.7.23.

       ·   --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).

       ·   --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 6.1.2.1, “End-User Guidelines for Password Security”. You can use an option
           file to avoid giving the password on the command line.

       ·   --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 6.3.9, “Pluggable Authentication”.

       ·   --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.

           As of MySQL 5.7.5, this option is deprecated and will be removed in a future MySQL
           release. It is always enabled and attempting to disable it (--skip-secure-auth,
           --secure-auth=0) produces an error. Before MySQL 5.7.5, this option is enabled by
           default but can be disabled.

               Note
               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 was removed in MySQL 5.7.5. For account
               upgrade instructions, see Section 6.5.1.3, “Migrating Away from Pre-4.1 Password
               Hashing and the mysql_old_password Plugin”.

       ·   --server-public-key-path=file_name

           The path name to a file containing a client-side copy of the public key required by
           the server for RSA key pair-based password exchange. The file must be in PEM format.
           This option applies to clients that authenticate with the sha256_password or
           caching_sha2_password authentication plugin. This option is ignored for accounts that
           do not authenticate with one of those plugins. It is also ignored if RSA-based
           password exchange is not used, as is the case when the client connects to the server
           using a secure connection.

           If --server-public-key-path=file_name is given and specifies a valid public key file,
           it takes precedence over --get-server-public-key.

           For sha256_password, this option applies only if MySQL was built using OpenSSL.

           For information about the sha256_password and caching_sha2_password plugins, see
           Section 6.5.1.4, “SHA-256 Pluggable Authentication”, and Section 6.5.1.5, “Caching
           SHA-2 Pluggable Authentication”.

           The --server-public-key-path option was added in MySQL 5.7.23.

       ·   --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.

       ·   --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.

       ·   --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 6.4.2, “Command Options
           for Encrypted Connections”.

       ·   --tables

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

       ·   --tls-version=protocol_list

           The protocols permitted by the client for encrypted connections. The value is a
           comma-separated list containing one or more protocol names. The protocols that can be
           named for this option depend on the SSL library used to compile MySQL. For details,
           see Section 6.4.6, “Encrypted Connection Protocols and Ciphers”.

           This option was added in MySQL 5.7.10.

       ·   --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 backup.

COPYRIGHT

       Copyright © 1997, 2018, 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 http://www.gnu.org/licenses/.

SEE ALSO

       For more information, please refer to the MySQL Reference Manual, which may already be
       installed locally and which is also available online at http://dev.mysql.com/doc/.

AUTHOR

       Oracle Corporation (http://dev.mysql.com/).