mysqlcheck
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 15.3.6, "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 15.7.3, "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 3.14,
"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 6.2.2.2, "Using Option Files".
o --help, -?
+--------------------+--------+
|Command-Line Format | --help |
+--------------------+--------+
Display a help message and exit.
o --all-databases, -A
+--------------------+-----------------+
|Command-Line Format | --all-databases |
+--------------------+-----------------+
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
+--------------------+------------+
|Command-Line Format | --all-in-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
+--------------------+-----------+
|Command-Line Format | --analyze |
+--------------------+-----------+
Analyze the tables.
o --auto-repair
+--------------------+---------------+
|Command-Line Format | --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
+--------------------+---------------------------+
|Command-Line Format | --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
+--------------------+-------------------+
|Command-Line Format | --character-sets- |
| | dir=dir_name |
+--------------------+-------------------+
|Type | Directory name |
+--------------------+-------------------+
The directory where character sets are installed. See
Section 12.15, "Character Set Configuration".
o --check, -c
+--------------------+---------+
|Command-Line Format | --check |
+--------------------+---------+
Check the tables for errors. This is the default operation.
o --check-only-changed, -C
+--------------------+----------------------+
|Command-Line Format | --check-only-changed |
+--------------------+----------------------+
Check only tables that have changed since the last check or that
have not been closed properly.
o --check-upgrade, -g
+--------------------+-----------------+
|Command-Line Format | --check-upgrade |
+--------------------+-----------------+
Invoke CHECK TABLE with the FOR UPGRADE option to check tables for
incompatibilities with the current version of the server.
o --compress
+--------------------+-----------------------+
|Command-Line Format | --compress[={OFF|ON}] |
+--------------------+-----------------------+
|Deprecated | 8.0.18 |
+--------------------+-----------------------+
|Type | Boolean |
+--------------------+-----------------------+
|Default Value | OFF |
+--------------------+-----------------------+
Compress all information sent between the client and the server if
possible. See Section 6.2.8, "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
+--------------------+-------------------------+
|Command-Line Format | --compression- |
| | algorithms=value |
+--------------------+-------------------------+
|Introduced | 8.0.18 |
+--------------------+-------------------------+
|Type | Set |
+--------------------+-------------------------+
|Default Value | uncompressed |
+--------------------+-------------------------+
|Valid Values | |
| | zlib |
| | |
| | zstd |
| | |
| | uncompressed |
+--------------------+-------------------------+
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 6.2.8, "Connection Compression
Control".
This option was added in MySQL 8.0.18.
o --databases, -B
+--------------------+-------------+
|Command-Line Format | --databases |
+--------------------+-------------+
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]
+--------------------+-------------------------+
|Command-Line Format | --debug[=debug_options] |
+--------------------+-------------------------+
|Type | String |
+--------------------+-------------------------+
|Default Value | d:t:o |
+--------------------+-------------------------+
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
+--------------------+---------------+
|Command-Line Format | --debug-check |
+--------------------+---------------+
|Type | Boolean |
+--------------------+---------------+
|Default Value | FALSE |
+--------------------+---------------+
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
+--------------------+--------------+
|Command-Line Format | --debug-info |
+--------------------+--------------+
|Type | Boolean |
+--------------------+--------------+
|Default Value | FALSE |
+--------------------+--------------+
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
+--------------------+----------------------+
|Command-Line Format | --default-character- |
| | set=charset_name |
+--------------------+----------------------+
|Type | String |
+--------------------+----------------------+
Use charset_name as the default character set. See Section 12.15,
"Character Set Configuration".
o --defaults-extra-file=file_name
+--------------------+-------------------+
|Command-Line Format | --defaults-extra- |
| | file=file_name |
+--------------------+-------------------+
|Type | 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 6.2.2.3, "Command-Line Options that Affect
Option-File Handling".
o --defaults-file=file_name
+--------------------+---------------------------+
|Command-Line Format | --defaults-file=file_name |
+--------------------+---------------------------+
|Type | 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 6.2.2.3, "Command-Line Options that Affect
Option-File Handling".
o --defaults-group-suffix=str
+--------------------+-------------------+
|Command-Line Format | --defaults-group- |
| | suffix=str |
+--------------------+-------------------+
|Type | String |
+--------------------+-------------------+
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 6.2.2.3, "Command-Line Options that Affect
Option-File Handling".
o --extended, -e
+--------------------+------------+
|Command-Line Format | --extended |
+--------------------+------------+
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
+--------------------+-----------------------+
|Command-Line Format | --default-auth=plugin |
+--------------------+-----------------------+
|Type | String |
+--------------------+-----------------------+
A hint about which client-side authentication plugin to use. See
Section 8.2.17, "Pluggable Authentication".
o --enable-cleartext-plugin
+--------------------+---------------------------+
|Command-Line Format | --enable-cleartext-plugin |
+--------------------+---------------------------+
|Type | Boolean |
+--------------------+---------------------------+
|Default Value | FALSE |
+--------------------+---------------------------+
Enable the mysql_clear_password cleartext authentication plugin.
(See Section 8.4.1.4, "Client-Side Cleartext Pluggable
Authentication".)
o --fast, -F
+--------------------+--------+
|Command-Line Format | --fast |
+--------------------+--------+
Check only tables that have not been closed properly.
o --force, -f
+--------------------+---------+
|Command-Line Format | --force |
+--------------------+---------+
Continue even if an SQL error occurs.
o --get-server-public-key
+--------------------+-------------------------+
|Command-Line Format | --get-server-public-key |
+--------------------+-------------------------+
|Type | Boolean |
+--------------------+-------------------------+
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 8.4.1.2, "Caching SHA-2 Pluggable Authentication".
o --host=host_name, -h host_name
+--------------------+------------------+
|Command-Line Format | --host=host_name |
+--------------------+------------------+
|Type | String |
+--------------------+------------------+
|Default Value | localhost |
+--------------------+------------------+
Connect to the MySQL server on the given host.
o --login-path=name
+--------------------+-------------------+
|Command-Line Format | --login-path=name |
+--------------------+-------------------+
|Type | String |
+--------------------+-------------------+
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 6.2.2.3, "Command-Line Options that Affect
Option-File Handling".
o --medium-check, -m
+--------------------+----------------+
|Command-Line Format | --medium-check |
+--------------------+----------------+
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
+--------------------+---------------+
|Command-Line Format | --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 6.2.2.3, "Command-Line Options that Affect
Option-File Handling".
o --optimize, -o
+--------------------+------------+
|Command-Line Format | --optimize |
+--------------------+------------+
Optimize the tables.
o --password[=password], -p[password]
+--------------------+-----------------------+
|Command-Line Format | --password[=password] |
+--------------------+-----------------------+
|Type | String |
+--------------------+-----------------------+
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 8.1.2.1, "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 8.1.2.1, "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
+--------------------+--------+
|Command-Line Format | --pipe |
+--------------------+--------+
|Type | String |
+--------------------+--------+
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
+--------------------+-----------------------+
|Command-Line Format | --plugin-dir=dir_name |
+--------------------+-----------------------+
|Type | Directory 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 8.2.17,
"Pluggable Authentication".
o --port=port_num, -P port_num
+--------------------+-----------------+
|Command-Line Format | --port=port_num |
+--------------------+-----------------+
|Type | Numeric |
+--------------------+-----------------+
|Default Value | 3306 |
+--------------------+-----------------+
For TCP/IP connections, the port number to use.
o --print-defaults
+--------------------+------------------+
|Command-Line Format | --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 6.2.2.3, "Command-Line Options that Affect
Option-File Handling".
o --protocol={TCP|SOCKET|PIPE|MEMORY}
+--------------------+-------------------+
|Command-Line Format | --protocol=type |
+--------------------+-------------------+
|Type | String |
+--------------------+-------------------+
|Default Value | [see text] |
+--------------------+-------------------+
|Valid Values | |
| | 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 6.2.7, "Connection Transport
Protocols".
o --quick, -q
+--------------------+---------+
|Command-Line Format | --quick |
+--------------------+---------+
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
+--------------------+----------+
|Command-Line Format | --repair |
+--------------------+----------+
Perform a repair that can fix almost anything except unique keys
that are not unique.
o --server-public-key-path=file_name
+--------------------+----------------------+
|Command-Line Format | --server-public-key- |
| | path=file_name |
+--------------------+----------------------+
|Type | 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 8.4.1.3, "SHA-256 Pluggable Authentication",
and Section 8.4.1.2, "Caching SHA-2 Pluggable Authentication".
o --shared-memory-base-name=name
+--------------------+-----------------------+
|Command-Line Format | --shared-memory-base- |
| | name=name |
+--------------------+-----------------------+
|Platform Specific | Windows |
+--------------------+-----------------------+
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
+--------------------+----------+
|Command-Line Format | --silent |
+--------------------+----------+
Silent mode. Print only error messages.
o --skip-database=db_name
+--------------------+-------------------------+
|Command-Line Format | --skip-database=db_name |
+--------------------+-------------------------+
Do not include the named database (case-sensitive) in the
operations performed by mysqlcheck.
o --socket=path, -S path
+--------------------+--------------------------------+
|Command-Line Format | --socket={file_name|pipe_name} |
+--------------------+--------------------------------+
|Type | String |
+--------------------+--------------------------------+
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}
+--------------------+----------------------+
|Command-Line Format | --ssl-fips- |
| | mode={OFF|ON|STRICT} |
+--------------------+----------------------+
|Deprecated | 8.0.34 |
+--------------------+----------------------+
|Type | Enumeration |
+--------------------+----------------------+
|Default Value | OFF |
+--------------------+----------------------+
|Valid Values | |
| | 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 8.8,
"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
+--------------------+----------+
|Command-Line Format | --tables |
+--------------------+----------+
Override the --databases or -B option. All name arguments following
the option are regarded as table names.
o --tls-ciphersuites=ciphersuite_list
+--------------------+-------------------------------+
|Command-Line Format | --tls- |
| | ciphersuites=ciphersuite_list |
+--------------------+-------------------------------+
|Introduced | 8.0.16 |
+--------------------+-------------------------------+
|Type | String |
+--------------------+-------------------------------+
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 8.3.2, "Encrypted Connection TLS Protocols and
Ciphers".
This option was added in MySQL 8.0.16.
o --tls-version=protocol_list
+--------------------------+------------------------------------------+
|Command-Line Format | --tls- |
| | version=protocol_list |
+--------------------------+------------------------------------------+
|Type | String |
+--------------------------+------------------------------------------+
|Default Value (>= 8.0.16) | |
| | TLSv1,TLSv1.1,TLSv1.2,TLSv1.3 |
| | (OpenSSL 1.1.1 |
| | or higher) |
| | |
| | TLSv1,TLSv1.1,TLSv1.2 |
| | (otherwise) |
+--------------------------+------------------------------------------+
|Default Value (<= 8.0.15) | TLSv1,TLSv1.1,TLSv1.2 |
+--------------------------+------------------------------------------+
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 8.3.2,
"Encrypted Connection TLS Protocols and Ciphers".
o --use-frm
+--------------------+-----------+
|Command-Line Format | --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
+--------------------+-------------------+
|Command-Line Format | --user=user_name, |
+--------------------+-------------------+
|Type | String |
+--------------------+-------------------+
The user name of the MySQL account to use for connecting to the
server.
o --verbose, -v
+--------------------+-----------+
|Command-Line Format | --verbose |
+--------------------+-----------+
Verbose mode. Print information about the various stages of program
operation.
o --version, -V
+--------------------+-----------+
|Command-Line Format | --version |
+--------------------+-----------+
Display version information and exit.
o --write-binlog
+--------------------+----------------+
|Command-Line Format | --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
+--------------------+----------------------------+
|Command-Line Format | --zstd-compression-level=# |
+--------------------+----------------------------+
|Introduced | 8.0.18 |
+--------------------+----------------------------+
|Type | Integer |
+--------------------+----------------------------+
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 6.2.8, "Connection Compression
Control".
This option was added in MySQL 8.0.18.
COPYRIGHT
Copyright (C) 1997, 2024, 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 12/13/2024 MYSQLCHECK(1)
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