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 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 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:
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 2.11.13, “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 4.2.2.2, “Using Option Files”.
Table 4.12 mysqlcheck Options
Option Name | Description | Introduced | Removed |
---|---|---|---|
--all-databases | Check all tables in all databases | ||
--all-in-1 | Execute a single statement for each database that names all the tables from that database | ||
--analyze | Analyze the tables | ||
--auto-repair | If a checked table is corrupted, automatically fix it | ||
--bind-address | Use specified network interface to connect to MySQL Server | ||
--character-sets-dir | Directory where character sets are installed | ||
--check | Check the tables for errors | ||
--check-only-changed | Check only tables that have changed since the last check | ||
--check-upgrade | Invoke CHECK TABLE with the FOR UPGRADE option | ||
--compress | Compress all information sent between client and server | ||
--databases | Interpret all arguments as database names | ||
--debug | Write debugging log | ||
--debug-check | Print debugging information when program exits | ||
--debug-info | Print debugging information, memory, and CPU statistics when program exits | ||
--default-auth | Authentication plugin to use | ||
--default-character-set | Specify default character set | ||
--defaults-extra-file | Read named option file in addition to usual option files | ||
--defaults-file | Read only named option file | ||
--defaults-group-suffix | Option group suffix value | ||
--enable-cleartext-plugin | Enable cleartext authentication plugin | ||
--extended | Check and repair tables | ||
--fast | Check only tables that have not been closed properly | ||
--force | Continue even if an SQL error occurs | ||
--get-server-public-key | Request RSA public key from server | 8.0.3 | |
--help | Display help message and exit | ||
--host | Connect to MySQL server on given host | ||
--login-path | Read login path options from .mylogin.cnf | ||
--medium-check | Do a check that is faster than an --extended operation | ||
--no-defaults | Read no option files | ||
--optimize | Optimize the tables | ||
--password | Password to use when connecting to server | ||
--pipe | Connect to server using named pipe (Windows only) | ||
--plugin-dir | Directory where plugins are installed | ||
--port | TCP/IP port number for connection | ||
--print-defaults | Print default options | ||
--protocol | Connection protocol to use | ||
--quick | The fastest method of checking | ||
--repair | Perform a repair that can fix almost anything except unique keys that are not unique | ||
--secure-auth | Do not send passwords to server in old (pre-4.1) format | 8.0.3 | |
--server-public-key-path | Path name to file containing RSA public key | 8.0.4 | |
--shared-memory-base-name | Name of shared memory to use for shared-memory connections | ||
--silent | Silent mode | ||
--skip-database | Omit this database from performed operations | ||
--socket | The Unix socket file or Windows named pipe to use | ||
--ssl-ca | File that contains list of trusted SSL Certificate Authorities | ||
--ssl-capath | Directory that contains trusted SSL Certificate Authority certificate files | ||
--ssl-cert | File that contains X.509 certificate | ||
--ssl-cipher | Permissible ciphers for connection encryption | ||
--ssl-crl | File that contains certificate revocation lists | ||
--ssl-crlpath | Directory that contains certificate revocation-list files | ||
--ssl-fips-mode | Whether to enable FIPS mode on client side | 8.0.11 | |
--ssl-key | File that contains X.509 key | ||
--ssl-mode | Desired security state of connection to server | ||
--tables | Overrides the --databases or -B option | ||
--tls-ciphersuites | Permissible TLSv1.3 ciphersuites for encrypted connections | 8.0.16 | |
--tls-version | Permissible TLS protocols for encrypted connections | ||
--use-frm | For repair operations on MyISAM tables | ||
--user | MySQL user name to use when connecting to server | ||
--verbose | Verbose mode | ||
--version | Display version information and exit | ||
--write-binlog | Log ANALYZE, OPTIMIZE, REPAIR statements to binary log. --skip-write-binlog adds NO_WRITE_TO_BINLOG to these statements. |
--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 theINFORMATION_SCHEMA
andperformance_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.
If a checked table is corrupted, automatically fix it. Any necessary repairs are done after all tables have been checked.
On a computer having multiple network interfaces, use this option to select which interface to use for connecting to the MySQL server.
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 tables that have changed since the last check or that have not been closed properly.
--check-upgrade
,-g
Invoke
CHECK TABLE
with theFOR UPGRADE
option to check tables for incompatibilities with the current version of the server.Compress all information sent between the client and the server if possible. See Section 4.2.6, “Connection Compression Control”.
--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 isd:t:o,
. The default isfile_name
d:t:o
.Print some debugging information when the program exits.
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.For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
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
.For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
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.For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--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!
A hint about which client-side authentication plugin to use. See Section 6.2.17, “Pluggable Authentication”.
Enable the
mysql_clear_password
cleartext authentication plugin. (See Section 6.4.1.4, “Client-Side Cleartext Pluggable Authentication”.)--fast
,-F
Check only tables that have not been closed properly.
--force
,-f
Continue even if an SQL error occurs.
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=
is given and specifies a valid public key file, it takes precedence overfile_name
--get-server-public-key
.For information about the
caching_sha2_password
plugin, see Section 6.4.1.3, “Caching SHA-2 Pluggable Authentication”.--host=
,host_name
-h
host_name
Connect to the MySQL server on the given host.
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 Section 4.6.7, “mysql_config_editor — MySQL Configuration Utility”.For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--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.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 Section 4.6.7, “mysql_config_editor — MySQL Configuration Utility”.)For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
--optimize
,-o
Optimize the tables.
--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.--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 thenamed_pipe_full_access_group
system variable.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”.--port=
,port_num
-P
port_num
For TCP/IP connections, the port number to use.
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”.
--protocol={TCP|SOCKET|PIPE|MEMORY}
The connection 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 4.2.4, “Connecting to the MySQL Server Using Command Options”.
--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.
This option was removed in MySQL 8.0.3.
--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
orcaching_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=
is given and specifies a valid public key file, it takes precedence overfile_name
--get-server-public-key
.For
sha256_password
, this option applies only if MySQL was built using OpenSSL.For information about the
sha256_password
andcaching_sha2_password
plugins, see Section 6.4.1.2, “SHA-256 Pluggable Authentication”, and Section 6.4.1.3, “Caching SHA-2 Pluggable Authentication”.--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.--silent
,-s
Silent mode. Print only error messages.
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.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 thenamed_pipe_full_access_group
system variable.Options that begin with
--ssl
specify whether to connect to the server using SSL and indicate where to find SSL keys and certificates. See Command Options for Encrypted Connections.--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-
options in that it is not used to establish encrypted connections, but rather to affect which cryptographic operations are permitted. See Section 6.5, “FIPS Support”.xxx
These
--ssl-fips-mode
values are permitted:OFF
: Disable FIPS mode.ON
: Enable FIPS mode.STRICT
: Enable “strict” FIPS mode.
NoteIf the OpenSSL FIPS Object Module is not available, the only permitted value for
--ssl-fips-mode
isOFF
. In this case, setting--ssl-fips-mode
toON
orSTRICT
causes the client to produce a warning at startup and to operate in non-FIPS mode.Override the
--databases
or-B
option. All name arguments following the option are regarded as table names.--tls-ciphersuites=
ciphersuite_list
The permissible TLSv1.3 ciphersuites for encrypted connections. 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 6.3.5, “Encrypted Connection Protocols and Ciphers”.
This option was added in MySQL 8.0.16.
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 6.3.5, “Encrypted Connection Protocols and Ciphers”.
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.--user=
,user_name
-u
user_name
The user name of the MySQL account to use for connecting to the server.
--verbose
,-v
Verbose mode. Print information about the various stages of program operation.
--version
,-V
Display version information and exit.
This option is enabled by default, so that
ANALYZE TABLE
,OPTIMIZE TABLE
, andREPAIR TABLE
statements generated by mysqlcheck are written to the binary log. Use--skip-write-binlog
to causeNO_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.