mysqloptimize
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 13.3.6, "LOCK TABLES and
UNLOCK TABLES Statements", 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 the MySQL upgrade procedure if it determines that table checking is
needed because it processes tables the same way.)
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 13.7.3, "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:
$> 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 2.10.13,
"Rebuilding or Repairing Tables or Indexes" for manual table repair
strategies. This is 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:
mysqlcheck [options] db_name [tbl_name ...]
mysqlcheck [options] --databases db_name ...
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 4.2.2.2, "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
performance_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 10.15, "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.
o --compress Compress all information sent between the client and the
server if possible. See Section 4.2.8, "Connection Compression
Control".
As of MySQL 8.0.18, this option is deprecated. Expect it to be
removed in a future version of MySQL. See the section called
"Configuring Legacy Connection Compression".
o --compression-algorithms=value The permitted compression algorithms
for connections to the server. The available algorithms are the
same as for the protocol_compression_algorithms system variable.
The default value is uncompressed.
For more information, see Section 4.2.8, "Connection Compression
Control".
This option was added in MySQL 8.0.18.
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.
This option is available only if MySQL was built using WITH_DEBUG.
MySQL release binaries provided by Oracle are not built using this
option.
o --debug-check Print some debugging information when the program
exits.
This option is available only if MySQL was built using WITH_DEBUG.
MySQL release binaries provided by Oracle are not built using this
option.
o --debug-info Print debugging information and memory and CPU usage
statistics when the program exits.
This option is available only if MySQL was built using WITH_DEBUG.
MySQL release binaries provided by Oracle are not built using this
option.
o --default-character-set=charset_name Use charset_name as the
default character set. See Section 10.15, "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. If file_name is not an absolute path name, it is
interpreted relative to the current directory.
For additional information about this and other option-file
options, see Section 4.2.2.3, "Command-Line Options that Affect
Option-File Handling".
o --defaults-file=file_name Use only the given option file. If the
file does not exist or is otherwise inaccessible, an error occurs.
If file_name is not an absolute path name, it is interpreted
relative to the current directory.
Exception: Even with --defaults-file, client programs read
.mylogin.cnf.
For additional information about this and other option-file
options, see Section 4.2.2.3, "Command-Line Options that Affect
Option-File Handling".
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 this option is given as --defaults-group-suffix=_other,
mysqlcheck also reads the [client_other] and [mysqlcheck_other]
groups.
For additional information about this and other option-file
options, see Section 4.2.2.3, "Command-Line Options that Affect
Option-File Handling".
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 which client-side authentication
plugin to use. See Section 6.2.17, "Pluggable Authentication".
o --enable-cleartext-plugin Enable the mysql_clear_password cleartext
authentication plugin. (See Section 6.4.1.4, "Client-Side Cleartext
Pluggable Authentication".)
o --fast, -F Check only tables that have not been closed properly.
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 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 6.4.1.2, "Caching SHA-2 Pluggable Authentication".
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).
For additional information about this and other option-file
options, see Section 4.2.2.3, "Command-Line Options that Affect
Option-File Handling".
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 is read in all cases,
if it exists. This permits passwords to be specified in a safer way
than on the command line even when --no-defaults is used. To create
.mylogin.cnf, use the mysql_config_editor utility. See
mysql_config_editor(1).
For additional information about this and other option-file
options, see Section 4.2.2.3, "Command-Line Options that Affect
Option-File Handling".
o --optimize, -o Optimize the tables.
o --password[=password], -p[password] The password of the MySQL
account used for connecting to the server. The password value is
optional. If not given, mysqlcheck prompts for one. If given, there
must be no space between --password= or -p and the password
following it. If no password option is specified, the default is to
send no password.
Specifying a password on the command line should be considered
insecure. To avoid giving the password on the command line, use an
option file. See Section 6.1.2.1, "End-User Guidelines for Password
Security".
To explicitly specify that there is no password and that mysqlcheck
should not prompt for one, use the --skip-password option.
o --password1[=pass_val] The password for multifactor authentication
factor 1 of the MySQL account used for connecting to the server.
The password value is optional. If not given, mysqlcheck prompts
for one. If given, there must be no space between --password1= and
the password following it. If no password option is specified, the
default is to send no password.
Specifying a password on the command line should be considered
insecure. To avoid giving the password on the command line, use an
option file. See Section 6.1.2.1, "End-User Guidelines for Password
Security".
To explicitly specify that there is no password and that mysqlcheck
should not prompt for one, use the --skip-password1 option.
--password1 and --password are synonymous, as are --skip-password1
and --skip-password.
o --password2[=pass_val] The password for multifactor authentication
factor 2 of the MySQL account used for connecting to the server.
The semantics of this option are similar to the semantics for
--password1; see the description of that option for details.
o --password3[=pass_val] The password for multifactor authentication
factor 3 of the MySQL account used for connecting to the server.
The semantics of this option are similar to the semantics for
--password1; see the description of that option for details.
o --pipe, -W On Windows, connect to the server using a named pipe.
This option applies only if the server was started with the
named_pipe system variable enabled to support named-pipe
connections. In addition, the user making the connection must be a
member of the Windows group specified by the
named_pipe_full_access_group system variable.
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 6.2.17, "Pluggable Authentication".
o --port=port_num, -P port_num For TCP/IP connections, the port
number to use.
o --print-defaults Print the program name and all options that it
gets from option files.
For additional information about this and other option-file
options, see Section 4.2.2.3, "Command-Line Options that Affect
Option-File Handling".
o --protocol={TCP|SOCKET|PIPE|MEMORY} The transport protocol to use
for connecting to the server. It is useful when the other
connection parameters normally result in use of a protocol other
than the one you want. For details on the permissible values, see
Section 4.2.7, "Connection Transport Protocols".
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 --server-public-key-path=file_name The path name to a file in PEM
format containing a client-side copy of the public key required by
the server for RSA key pair-based password exchange. 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 6.4.1.3, "SHA-256 Pluggable Authentication",
and Section 6.4.1.2, "Caching SHA-2 Pluggable Authentication".
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.
This option applies only if the server was started with the
shared_memory system variable enabled to support 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.
On Windows, this option applies only if the server was started with
the named_pipe system variable enabled to support named-pipe
connections. In addition, the user making the connection must be a
member of the Windows group specified by the
named_pipe_full_access_group system variable.
o --ssl* Options that begin with --ssl specify whether to connect to
the server using encryption and indicate where to find SSL keys and
certificates. See the section called "Command Options for Encrypted
Connections".
o --ssl-fips-mode={OFF|ON|STRICT} Controls whether to enable FIPS
mode on the client side. The --ssl-fips-mode option differs from
other --ssl-xxx options in that it is not used to establish
encrypted connections, but rather to affect which cryptographic
operations to permit. See Section 6.8, "FIPS Support".
These --ssl-fips-mode values are permitted:
o OFF: Disable FIPS mode.
o ON: Enable FIPS mode.
o STRICT: Enable "strict" FIPS mode.
Note
If the OpenSSL FIPS Object Module is not available, the only
permitted value for --ssl-fips-mode is OFF. In this case,
setting --ssl-fips-mode to ON or STRICT causes the client to
produce a warning at startup and to operate in non-FIPS mode.
As of MySQL 8.0.34, this option is deprecated. Expect it to be
removed in a future version of MySQL.
o --tables Override the --databases or -B option. All name arguments
following the option are regarded as table names.
o --tls-ciphersuites=ciphersuite_list The permissible ciphersuites
for encrypted connections that use TLSv1.3. The value is a list of
one or more colon-separated ciphersuite names. The ciphersuites
that can be named for this option depend on the SSL library used to
compile MySQL. For details, see Section 6.3.2, "Encrypted
Connection TLS Protocols and Ciphers".
This option was added in MySQL 8.0.16.
o --tls-version=protocol_list The permissible TLS protocols for
encrypted connections. The value is a list of one or more
comma-separated protocol names. The protocols that can be named for
this option depend on the SSL library used to compile MySQL. For
details, see Section 6.3.2, "Encrypted Connection TLS Protocols and
Ciphers".
o --use-frm For repair operations on MyISAM tables, get the table
structure from the data dictionary so that the table can be
repaired even if the .MYI header is corrupted.
o --user=user_name, -u user_name The user name of the MySQL account
to use for 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 replicas or run when using the
binary logs for recovery from backup.
o --zstd-compression-level=level The compression level to use for
connections to the server that use the zstd compression algorithm.
The permitted levels are from 1 to 22, with larger values
indicating increasing levels of compression. The default zstd
compression level is 3. The compression level setting has no effect
on connections that do not use zstd compression.
For more information, see Section 4.2.8, "Connection Compression
Control".
This option was added in MySQL 8.0.18.
COPYRIGHT
Copyright (C) 1997, 2023, Oracle and/or its affiliates.
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 8.0 08/31/2023 MYSQLCHECK(1)
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