MySQL 8.0 Reference Manual Including MySQL NDB Cluster 8.0

4.4.5 mysql_upgrade — Check and Upgrade MySQL Tables


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:

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.


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]

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, “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.


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, “Using Option Files”.

Table 4.10 mysql_upgrade Options

Option Name Description Introduced Deprecated
--bind-address Use specified network interface to connect to MySQL Server
--character-sets-dir Directory where character sets are installed
--compress Compress all information sent between client and server 8.0.18
--compression-algorithms Permitted compression algorithms for connections to server 8.0.18
--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
--force Force execution even if mysql_upgrade has already been executed for current MySQL version
--get-server-public-key Request RSA public key from server
--help Display help message and exit
--host Host on which MySQL server is located
--login-path Read login path options from .mylogin.cnf
--max-allowed-packet Maximum packet length to send to or receive from server
--net-buffer-length Buffer size for TCP/IP and socket communication
--no-defaults Read no option files
--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 Transport protocol to use
--server-public-key-path Path name to file containing RSA public key
--shared-memory-base-name Shared-memory name for shared-memory connections (Windows only)
--skip-sys-schema Do not install or upgrade sys schema
--socket 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 8.0.34
--ssl-key File that contains X.509 key
--ssl-mode Desired security state of connection to server
--ssl-session-data File that contains SSL session data 8.0.29
--ssl-session-data-continue-on-failed-reuse Whether to establish connections if session reuse fails 8.0.29
--tls-ciphersuites Permissible TLSv1.3 ciphersuites for encrypted connections 8.0.16
--tls-version Permissible TLS protocols for encrypted connections
--upgrade-system-tables Update only system tables, not user schemas
--user MySQL user name to use when connecting to server
--verbose Verbose mode
--version-check Check for proper server version
--write-binlog Write all statements to binary log
--zstd-compression-level Compression level for connections to server that use zstd compression 8.0.18