Upgrade your Libraries: Authentication Plugin ‘caching_sha2_password’ Cannot be Loaded

For my previous blog post on the topic, I received plenty of questions about why I did not cover the caching_sha2_password  plugin. This plugin is the default since MySQL 8, and all user accounts which are created without the option IDENTIFIED WITH, will use this plugin. Locally everything works fine because the plugin is built-in to the MySQL server and client.

If you then connect with such a user account from a remote machine you may get an error similar to:

Unlike the situation, mentioned in the other blog post, the reason for this error is not always the --plugin-dir  option of the mysql  client. More often this means that you did not upgrade MySQL client libraries.

Plugin caching_sha2_password  was first introduced in MySQL 5.7. If you somehow still use MySQL 5.6 or an earlier version, you would not be able to connect to MySQL using this plugin.

Some operating systems have MariaDB packages in place of MySQL.

MariaDB server does not support the caching_sha2_password  plugin. But MariaDB Connector/C does support this plugin since version 3.0.2. The plugin is not built-in and is provided as a separate library. All clients that use MariaDB Connector/C support authentication with the caching_sha2_password  plugin. This includes mysql and mariadb  command-line clients.

MariaDB libmysqlclient library does not support the caching_sha2_password  plugin. Therefore, if you use a client linked to this library, you would not be able to authenticate with the caching_sha2_password  plugin.

Applications that connect to MySQL using different APIs, such as Python, PHP, Go, Java, and ODBC need to use the latest version of the connectors and database drivers. Both MySQL and MariaDB connectors support the caching_sha2_password  plugin.

This also applies to Percona Toolkit.

Conclusion

In order to use the caching_sha2_password  authentication plugin:

• For MySQL, Percona Server for MySQL, and Percona XtraDB Cluster

  • Use client version 5.7 or newer
  • No other actions are needed: support is built-in

• For MariaDB

  • Use client, linked with MariaDB Connector/C 3.0.2 or newer
  • Specify option --plugin-dir  if your client cannot find the caching_sha2_password.so  library in the default location