4.4.7. mysql_upgrade — Check Tables for MySQL Upgrade

mysql_upgrade examines all tables in all databases for incompatibilities with the current version of MySQL Server. mysql_upgrade also upgrades the system tables so that you can take advantage of new privileges or capabilities that might have been added.

mysql_upgrade should be executed each time you upgrade MySQL. It supersedes the older mysql_fix_privilege_tables script, which has been removed in MySQL 5.5.

If a table is found to have a possible incompatibility, mysql_upgrade performs a table check. If any problems are found, a table repair is attempted. If the table cannot be repaired, see Section 2.13.4, “Rebuilding or Repairing Tables or Indexes” for manual table repair strategies.


On Windows Server 2008 and Windows Vista, you must run mysql_upgrade with administrator privileges. You can do this by running a Command Prompt as Administrator and running the command. Failure to do so may result in the upgrade failing to execute correctly.


You should always back up your current MySQL installation before performing an upgrade. See Section 6.2, “Database Backup Methods”.

Some upgrade incompatibilities may require special handling before you upgrade your MySQL installation and run mysql_upgrade. See Section 2.13.1, “Upgrading MySQL”, for instructions on determining whether any such incompatibilities apply to your installation and how to handle them.

To use mysql_upgrade, make sure that the server is running, and then invoke it like this:

shell> mysql_upgrade [options]

After running mysql_upgrade, stop the server and restart it so that any changes made to the system tables take effect.

mysql_upgrade executes the following commands to check and repair tables and to upgrade the system tables:

mysqlcheck --all-databases --check-upgrade --auto-repair
mysql < fix_priv_tables
mysqlcheck --all-databases --check-upgrade --fix-db-names --fix-table-names

Notes about the preceding commands:

  • Because mysql_upgrade invokes mysqlcheck with the --all-databases option, it processes all tables in all databases, which 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.

  • For details about what checks the --check-upgrade option entails, see the description of the FOR UPGRADE option of the CHECK TABLE statement (see Section, “CHECK TABLE Syntax”).

  • fix_priv_tables represents a script generated internally by mysql_upgrade that contains SQL statements to upgrade the tables in the mysql database.

All checked and repaired tables are marked with the current MySQL version number. This ensures that next time you run mysql_upgrade with the same version of the server, it can tell whether there is any need to check or repair the table again.

mysql_upgrade also 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.

If you install MySQL from RPM packages on Linux, you must install the server and client RPMs. mysql_upgrade is included in the server RPM but requires the client RPM because the latter includes mysqlcheck. (See Section 2.5.1, “Installing MySQL from RPM Packages on Linux”.)

mysql_upgrade does not upgrade the contents of the help tables. For upgrade instructions, see Section 5.1.8, “Server-Side Help”.

mysql_upgrade supports the following options, which can be specified on the command line or in the [mysql_upgrade] and [client] option file groups. Other options are passed to mysqlcheck. For example, it might be necessary to specify the --password[=password] option. mysql_upgrade also supports the options for processing option files described at Section, “Command-Line Options that Affect Option-File Handling”.

  • --help

    Display a short help message and exit.

  • --basedir=path

    The path to the MySQL installation directory. This option is accepted for backward compatibility but ignored.

  • --datadir=path

    The path to the data directory. This option is accepted for backward compatibility but ignored.

  • --debug-check

    Print some debugging information when the program exits.

  • --debug-info, -T

    Print debugging information and memory and CPU usage statistics when the program exits.

  • --force

    Ignore the mysql_upgrade_info file and force execution of mysqlcheck even if mysql_upgrade has already been executed for the current version of MySQL.

  • --tmpdir=path, -t path

    The path name of the directory to use for creating temporary files.

  • --upgrade-system-tables, -s

    Upgrade only the system tables, do not upgrade data.

  • --user=user_name, -u user_name

    The MySQL user name to use when connecting to the server. The default user name is root.

  • --verbose

    Verbose mode. Print more information about what the program does.

  • --write-binlog

    Cause binary logging to be enabled while mysql_upgrade runs. This is the default behavior; to disable binary logging during the upgrade, use the inverse of this option (that is, start the program with --skip-write-binlog).

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