Some releases of MySQL introduce changes to the structure of the system tables in the mysql database to add new privileges or support new features. When you update to a new version of MySQL, you should update your system tables as well to make sure that their structure is up to date. Otherwise, there might be capabilities that you cannot take advantage of. First, make a backup of your mysql database, and then use the following procedure.

Note: As of MySQL 5.0.19, mysql_fix_privilege_tables is superseded by mysql_upgrade, which should be used instead. See Section 5.6.2, “mysql_upgrade — Check Tables for MySQL Upgrade”.

On Unix or Unix-like systems, update the system tables by running the mysql_fix_privilege_tables script:

shell> mysql_fix_privilege_tables

You must run this script while the server is running. It attempts to connect to the server running on the local host as root. If your root account requires a password, indicate the password on the command line like this:

shell> mysql_fix_privilege_tables --password=root_password

The mysql_fix_privilege_tables script performs any actions necessary to convert your system tables to the current format. You might see some Duplicate column name warnings as it runs; you can ignore them.

After running the script, stop the server and restart it.

On Windows systems, MySQL distributions include a mysql_fix_privilege_tables.sql SQL script that you can run using the mysql client. For example, if your MySQL installation is located at C:\Program Files\MySQL\MySQL Server 5.0, the commands look like this:

C:\> cd "C:\Program Files\MySQL\MySQL Server 5.0"
C:\> bin\mysql -u root -p mysql
mysql> SOURCE scripts/mysql_fix_privilege_tables.sql

The mysql command will prompt you for the root password; enter it when prompted.

If your installation is located in some other directory, adjust the pathnames appropriately.

As with the Unix procedure, you might see some Duplicate column name warnings as mysql processes the statements in the mysql_fix_privilege_tables.sql script; you can ignore them.

After running the script, stop the server and restart it.

mysql_upgrade should be executed each time you upgrade MySQL. It checks all tables in all databases for incompatibilities with the current version of MySQL Server. If a table is found to have a possible incompatibility, it is checked. If any problems are found, the table is repaired. mysql_upgrade also upgrades the system tables so that you can take advantage of new privileges or capabilities that might have been added.

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 if all tables have been checked for this release so that table-checking can be skipped. To ignore this file, use the --force option.

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

mysqlcheck --check-upgrade --all-databases --auto-repair
mysql_fix_privilege_tables

mysql_upgrade supersedes the older mysql_fix_privilege_tables script. In MySQL 5.0.19, mysql_upgrade was added as a shell script and worked only for Unix systems. As of MySQL 5.0.23, mysql_upgrade is an executable binary and is available on all systems. On systems older than those supporting mysql_upgrade, you can execute the mysqlcheck command manually, and then upgrade your system tables as described in Section 5.6.1, “mysql_fix_privilege_tables — Upgrade MySQL System Tables”.

For details about what is checked, see the description of the FOR UPGRADE option of the CHECK TABLE statement (see Section 13.5.2.3, “CHECK TABLE Syntax”).

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

shell> mysql_upgrade [options]

mysql_upgrade reads options from the command line and fromm the [mysqld] and [mysql_upgrade] groups in option files. It supports the following options:

Other options are passed to mysqlcheck and to mysql_fix_privilege_tables. For example, it might be necessary to specify the --password[=password] option.