Provided by: mysql-server-core-8.0_8.0.36-0ubuntu0.20.04.1_amd64 
NAME
mysql_upgrade - check and upgrade MySQL tables
SYNOPSIS
mysql_upgrade [options]
DESCRIPTION
Note
As of MySQL 8.0.16, the MySQL server performs the upgrade tasks previously handled by
mysql_upgrade (for details, see Section 2.10.3, “What the MySQL Upgrade Process
Upgrades”). Consequently, mysql_upgrade is unneeded and is deprecated as of that
version; expect it to be removed in a future version of MySQL. Because mysql_upgrade
no longer performs upgrade tasks, it exits with status 0 unconditionally.
Each time you upgrade MySQL, you should execute mysql_upgrade, which looks for
incompatibilities with the upgraded MySQL server:
• It upgrades the system tables in the mysql schema so that you can take advantage of
new privileges or capabilities that might have been added.
• It upgrades the Performance Schema, INFORMATION_SCHEMA, and sys schema.
• It examines user schemas.
If mysql_upgrade finds that a table has a possible incompatibility, it performs a table
check and, if problems are found, attempts a table repair. If the table cannot be
repaired, see Section 2.10.13, “Rebuilding or Repairing Tables or Indexes” for manual
table repair strategies.
mysql_upgrade communicates directly with the MySQL server, sending it the SQL statements
required to perform an upgrade.
Caution
You should always back up your current MySQL installation before performing an
upgrade. See Section 7.2, “Database Backup Methods”.
Some upgrade incompatibilities may require special handling before upgrading your
MySQL installation and running mysql_upgrade. See Section 2.10, “Upgrading MySQL”, for
instructions on determining whether any such incompatibilities apply to your
installation and how to handle them.
Use mysql_upgrade like this:
1. Ensure that the server is running.
2. Invoke mysql_upgrade to upgrade the system tables in the mysql schema and check and
repair tables in other schemas:
mysql_upgrade [options]
3. Stop the server and restart it so that any system table changes take effect.
If you have multiple MySQL server instances to upgrade, invoke mysql_upgrade with
connection parameters appropriate for connecting to each of the desired servers. For
example, with servers running on the local host on parts 3306 through 3308, upgrade each
of them by connecting to the appropriate port:
mysql_upgrade --protocol=tcp -P 3306 [other_options]
mysql_upgrade --protocol=tcp -P 3307 [other_options]
mysql_upgrade --protocol=tcp -P 3308 [other_options]
For local host connections on Unix, the --protocol=tcp option forces a connection using
TCP/IP rather than the Unix socket file.
By default, mysql_upgrade runs as the MySQL root user. If the root password is expired
when you run mysql_upgrade, it displays a message that your password is expired and that
mysql_upgrade failed as a result. To correct this, reset the root password to unexpire it
and run mysql_upgrade again. First, connect to the server as root:
$> mysql -u root -p
Enter password: **** <- enter root password here
Reset the password using ALTER USER:
mysql> ALTER USER USER() IDENTIFIED BY 'root-password';
Then exit mysql and run mysql_upgrade again:
$> mysql_upgrade [options]
Note
If you run the server with the disabled_storage_engines system variable set to disable
certain storage engines (for example, MyISAM), mysql_upgrade might fail with an error
like this:
mysql_upgrade: [ERROR] 3161: Storage engine MyISAM is disabled
(Table creation is disallowed).
To handle this, restart the server with disabled_storage_engines disabled. Then you
should be able to run mysql_upgrade successfully. After that, restart the server with
disabled_storage_engines set to its original value.
Unless invoked with the --upgrade-system-tables option, mysql_upgrade processes all tables
in all user schemas as necessary. Table checking might take a long time to complete. Each
table is locked and therefore unavailable to other sessions while it is being processed.
Check and repair operations can be time-consuming, particularly for large tables. Table
checking uses the FOR UPGRADE option of the CHECK TABLE statement. For details about what
this option entails, see Section 13.7.3.2, “CHECK TABLE Statement”.
mysql_upgrade marks all checked and repaired tables with the current MySQL version number.
This ensures that the next time you run mysql_upgrade with the same version of the server,
it can be determined whether there is any need to check or repair a given table again.
mysql_upgrade saves the MySQL version number in a file named mysql_upgrade_info in the
data directory. This is used to quickly check whether all tables have been checked for
this release so that table-checking can be skipped. To ignore this file and perform the
check regardless, use the --force option.
Note
The mysql_upgrade_info file is deprecated; expect it to be removed in a future version
of MySQL.
mysql_upgrade checks mysql.user system table rows and, for any row with an empty plugin
column, sets that column to 'mysql_native_password' if the credentials use a hash format
compatible with that plugin. Rows with a pre-4.1 password hash must be upgraded manually.
mysql_upgrade does not upgrade the contents of the time zone tables or help tables. For
upgrade instructions, see Section 5.1.15, “MySQL Server Time Zone Support”, and
Section 5.1.17, “Server-Side Help Support”.
Unless invoked with the --skip-sys-schema option, mysql_upgrade installs the sys schema if
it is not installed, and upgrades it to the current version otherwise. An error occurs if
a sys schema exists but has no version view, on the assumption that its absence indicates
a user-created schema:
A sys schema exists with no sys.version view. If
you have a user created sys schema, this must be renamed for the
upgrade to succeed.
To upgrade in this case, remove or rename the existing sys schema first.
mysql_upgrade supports the following options, which can be specified on the command line
or in the [mysql_upgrade] 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”.
• --help
┌────────────────────┬────────┐
│Command-Line Format │ --help │
└────────────────────┴────────┘
Display a short help message and exit.
• --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.
• --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 10.15, “Character Set
Configuration”.
• --compress, -C
┌────────────────────┬───────────────────────┐
│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 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”.
• --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 4.2.8, “Connection Compression Control”.
This option was added in MySQL 8.0.18.
• --debug[=debug_options], -# [debug_options]
┌────────────────────┬────────────────────────────────┐
│Command-Line Format │ --debug[=#] │
├────────────────────┼────────────────────────────────┤
│Type │ String │
├────────────────────┼────────────────────────────────┤
│Default Value │ d:t:O,/tmp/mysql_upgrade.trace │
└────────────────────┴────────────────────────────────┘
Write a debugging log. A typical debug_options string is d:t:o,file_name. The default
is d:t:O,/tmp/mysql_upgrade.trace.
• --debug-check
┌────────────────────┬───────────────┐
│Command-Line Format │ --debug-check │
├────────────────────┼───────────────┤
│Type │ Boolean │
└────────────────────┴───────────────┘
Print some debugging information when the program exits.
• --debug-info, -T
┌────────────────────┬──────────────┐
│Command-Line Format │ --debug-info │
├────────────────────┼──────────────┤
│Type │ Boolean │
├────────────────────┼──────────────┤
│Default Value │ FALSE │
└────────────────────┴──────────────┘
Print debugging information and memory and CPU usage statistics when the program
exits.
• --default-auth=plugin
┌────────────────────┬───────────────────────┐
│Command-Line Format │ --default-auth=plugin │
├────────────────────┼───────────────────────┤
│Type │ String │
└────────────────────┴───────────────────────┘
A hint about which client-side authentication plugin to use. See Section 6.2.17,
“Pluggable Authentication”.
• --default-character-set=charset_name
┌────────────────────┬──────────────────────────────┐
│Command-Line Format │ --default-character-set=name │
├────────────────────┼──────────────────────────────┤
│Type │ String │
└────────────────────┴──────────────────────────────┘
Use charset_name as the default character set. See Section 10.15, “Character Set
Configuration”.
• --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 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
• --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.
For additional information about this and other option-file options, see
Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
• --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, mysql_upgrade normally reads the [client] and
[mysql_upgrade] groups. If this option is given as --defaults-group-suffix=_other,
mysql_upgrade also reads the [client_other] and [mysql_upgrade_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”.
• --force
┌────────────────────┬─────────┐
│Command-Line Format │ --force │
├────────────────────┼─────────┤
│Type │ Boolean │
└────────────────────┴─────────┘
Ignore the mysql_upgrade_info file and force execution even if mysql_upgrade has
already been executed for the current version of MySQL.
• --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 6.4.1.2, “Caching
SHA-2 Pluggable Authentication”.
• --host=host_name, -h host_name
┌────────────────────┬─────────────┐
│Command-Line Format │ --host=name │
├────────────────────┼─────────────┤
│Type │ String │
└────────────────────┴─────────────┘
Connect to the MySQL server on the given host.
• --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 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
• --max-allowed-packet=value
┌────────────────────┬────────────────────────────┐
│Command-Line Format │ --max-allowed-packet=value │
├────────────────────┼────────────────────────────┤
│Type │ Integer │
├────────────────────┼────────────────────────────┤
│Default Value │ 25165824 │
├────────────────────┼────────────────────────────┤
│Minimum Value │ 4096 │
├────────────────────┼────────────────────────────┤
│Maximum Value │ 2147483648 │
└────────────────────┴────────────────────────────┘
The maximum size of the buffer for client/server communication. The default value is
24MB. The minimum and maximum values are 4KB and 2GB.
• --net-buffer-length=value
┌────────────────────┬───────────────────────────┐
│Command-Line Format │ --net-buffer-length=value │
├────────────────────┼───────────────────────────┤
│Type │ Integer │
├────────────────────┼───────────────────────────┤
│Default Value │ 1047552 │
├────────────────────┼───────────────────────────┤
│Minimum Value │ 4096 │
├────────────────────┼───────────────────────────┤
│Maximum Value │ 16777216 │
└────────────────────┴───────────────────────────┘
The initial size of the buffer for client/server communication. The default value is
1MB − 1KB. The minimum and maximum values are 4KB and 16MB.
• --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 4.2.2.3, “Command-Line Options that Affect Option-File Handling”.
• --password[=password], -p[password]
┌────────────────────┬───────────────────┐
│Command-Line Format │ --password[=name] │
├────────────────────┼───────────────────┤
│Type │ String │
└────────────────────┴───────────────────┘
The password of the MySQL account used for connecting to the server. The password
value is optional. If not given, mysql_upgrade 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 mysql_upgrade should not
prompt for one, use the --skip-password option.
• --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.
• --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 mysql_upgrade does not find it.
See Section 6.2.17, “Pluggable Authentication”.
• --port=port_num, -P port_num
┌────────────────────┬──────────┐
│Command-Line Format │ --port=# │
├────────────────────┼──────────┤
│Type │ Numeric │
└────────────────────┴──────────┘
For TCP/IP connections, the port number to use.
• --print-defaults
┌────────────────────┬──────────────────┐
│Command-Line Format │ --print-defaults │
└────────────────────┴──────────────────┘
Print the program name and all options that it gets from option files.
• --protocol={TCP|SOCKET|PIPE|MEMORY}
┌────────────────────┬─────────────────┐
│Command-Line Format │ --protocol=name │
├────────────────────┼─────────────────┤
│Type │ String │
└────────────────────┴─────────────────┘
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”.
• --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 6.4.1.3, “SHA-256 Pluggable Authentication”, and Section 6.4.1.2, “Caching
SHA-2 Pluggable Authentication”.
• --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.
• --skip-sys-schema
┌────────────────────┬───────────────────┐
│Command-Line Format │ --skip-sys-schema │
├────────────────────┼───────────────────┤
│Type │ Boolean │
├────────────────────┼───────────────────┤
│Default Value │ FALSE │
└────────────────────┴───────────────────┘
By default, mysql_upgrade installs the sys schema if it is not installed, and upgrades
it to the current version otherwise. The --skip-sys-schema option suppresses this
behavior.
• --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.
• --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”.
• --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 6.8, “FIPS Support”.
These --ssl-fips-mode values are permitted:
• OFF: Disable FIPS mode.
• ON: Enable FIPS mode.
• 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.
• --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 6.3.2, “Encrypted Connection TLS Protocols and Ciphers”.
This option was added in MySQL 8.0.16.
• --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 6.3.2,
“Encrypted Connection TLS Protocols and Ciphers”.
• --upgrade-system-tables, -s
┌────────────────────┬─────────────────────────┐
│Command-Line Format │ --upgrade-system-tables │
├────────────────────┼─────────────────────────┤
│Type │ Boolean │
└────────────────────┴─────────────────────────┘
Upgrade only the system tables in the mysql schema, do not upgrade user schemas.
• --user=user_name, -u user_name
┌────────────────────┬─────────────┐
│Command-Line Format │ --user=name │
├────────────────────┼─────────────┤
│Type │ String │
└────────────────────┴─────────────┘
The user name of the MySQL account to use for connecting to the server. The default
user name is root.
• --verbose
┌────────────────────┬───────────┐
│Command-Line Format │ --verbose │
├────────────────────┼───────────┤
│Type │ Boolean │
└────────────────────┴───────────┘
Verbose mode. Print more information about what the program does.
• --version-check, -k
┌────────────────────┬─────────────────┐
│Command-Line Format │ --version-check │
├────────────────────┼─────────────────┤
│Type │ Boolean │
└────────────────────┴─────────────────┘
Check the version of the server to which mysql_upgrade is connecting to verify that it
is the same as the version for which mysql_upgrade was built. If not, mysql_upgrade
exits. This option is enabled by default; to disable the check, use
--skip-version-check.
• --write-binlog
┌────────────────────┬────────────────┐
│Command-Line Format │ --write-binlog │
├────────────────────┼────────────────┤
│Type │ Boolean │
├────────────────────┼────────────────┤
│Default Value │ OFF │
└────────────────────┴────────────────┘
By default, binary logging by mysql_upgrade is disabled. Invoke the program with
--write-binlog if you want its actions to be written to the binary log.
When the server is running with global transaction identifiers (GTIDs) enabled
(gtid_mode=ON), do not enable binary logging by mysql_upgrade.
• --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 4.2.8, “Connection Compression Control”.
This option was added in MySQL 8.0.18.
COPYRIGHT
Copyright © 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/).