6.4.5 mysql_upgrade — Check and Upgrade MySQL Tables (original) (raw)

6.4.5 mysql_upgrade — Check and Upgrade MySQL Tables

Each time you upgrade MySQL, you should executemysql_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 3.14, “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. SeeSection 9.2, “Database Backup Methods”.

Some upgrade incompatibilities may require special handling_before_ upgrading your MySQL installation and running mysql_upgrade. SeeChapter 3, 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]
  1. Stop the server and restart it so that any system table changes take effect.

If you have multiple MySQL server instances to upgrade, invokemysql_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 MySQLroot user. If the root password is expired when you runmysql_upgrade, it displays a message that your password is expired and thatmysql_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 runmysql_upgrade again:

$> mysql_upgrade [options]

Note

If you run the server with thedisabled_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 withdisabled_storage_engines disabled. Then you should be able to runmysql_upgrade successfully. After that, restart the server withdisabled_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, seeSection 15.7.3.2, “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 checksmysql.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 7.1.15, “MySQL Server Time Zone Support”, andSection 7.1.17, “Server-Side Help Support”.

Unless invoked with the--skip-sys-schema option,mysql_upgrade installs thesys schema if it is not installed, and upgrades it to the current version otherwise. An error occurs if a sys schema exists but has noversion 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 existingsys 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, seeSection 6.2.2.2, “Using Option Files”.