mysqlrepair(1) - phpMan

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 2.11.13, "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.

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.

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.

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.

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 06/04/2022 MYSQLCHECK(1)

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