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MYSQLCHECK(1) MySQL Database System MYSQLCHECK(1)
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.
+--------------+----------------------------------+
|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".
o --help, -?
Display a help message and exit.
o --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.
o --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.
o --analyze, -a
Analyze the tables.
o --auto-repair
If a checked table is corrupted, automatically fix it. Any necessary repairs are done
after all tables have been checked.
o --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.
o --character-sets-dir=dir_name
The directory where character sets are installed. See Section 10.14, "Character Set
Configuration".
o --check, -c
Check the tables for errors. This is the default operation.
o --check-only-changed, -C
Check only tables that have changed since the last check or that have not been closed
properly.
o --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.
o --compress
Compress all information sent between the client and the server if both support
compression.
o --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.
o --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.
o --debug-check
Print some debugging information when the program exits.
o --debug-info
Print debugging information and memory and CPU usage statistics when the program
exits.
o --default-character-set=charset_name
Use charset_name as the default character set. See Section 10.14, "Character Set
Configuration".
o --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.
o --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.
o --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.
o --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!
o --default-auth=plugin
A hint about the client-side authentication plugin to use. See Section 6.3.9,
"Pluggable Authentication".
o --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.
o --fast, -F
Check only tables that have not been closed properly.
o --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.
o --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.
o --force, -f
Continue even if an SQL error occurs.
o --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.
o --host=host_name, -h host_name
Connect to the MySQL server on the given host.
o --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).
o --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.
o --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).)
o --optimize, -o
Optimize the tables.
o --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.
o --pipe, -W
On Windows, connect to the server using a named pipe. This option applies only if the
server supports named-pipe connections.
o --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".
o --port=port_num, -P port_num
The TCP/IP port number to use for the connection.
o --print-defaults
Print the program name and all options that it gets from option files.
o --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".
o --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.
o --repair, -r
Perform a repair that can fix almost anything except unique keys that are not unique.
o --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".
o --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.
o --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.
o --silent, -s
Silent mode. Print only error messages.
o --skip-database=db_name
Do not include the named database (case-sensitive) in the operations performed by
mysqlcheck.
o --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.
o --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".
o --tables
Override the --databases or -B option. All name arguments following the option are
regarded as table names.
o --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.
o --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.
o --user=user_name, -u user_name
The MySQL user name to use when connecting to the server.
o --verbose, -v
Verbose mode. Print information about the various stages of program operation.
o --version, -V
Display version information and exit.
o --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 (C) 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/).
MySQL 5.7 06/07/2018 MYSQLCHECK(1)
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On Apache
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