Version Tokens The option value should be one of those available for plugin-loading options, as described in Section 5.6.1, “Installing and Uninstalling Plugins” . For example,  --ddl-rewriter=OFF  disables the plugin at server startup. MySQL includes Version Tokens, a feature that enables creation of and synchronization around server tokens that applications can use to prevent accessing incorrect or out-of-date data. The Version Tokens interface has these characteristics: 5.6.6 Version Tokens The following sections describe the elements of Version Tokens, discuss how to install and use it, and provide reference information for its elements. Version Tokens is based on a plugin library that implements these elements: If installed, Version Tokens involves some overhead. To avoid this overhead, do not install it unless you plan to use it. This section describes how to install or uninstall Version Tokens, which is implemented in a plugin library file containing a plugin and loadable functions. For general information about installing or uninstalling 1098 Note 5.6.6.2 Installing or Uninstalling Version Tokens 5.6.6.1 Version Tokens Elements •A system variable enables clients to specify the list of version tokens that register the required server state. If the server has a different state when a client sends a statement, the client receives an error. •When the  version_tokens  plugin loads, it defines the  VERSION_TOKEN_ADMIN  dynamic privilege. This privilege can be granted to users of the functions. •A set of loadable functions provides an SQL-level API for manipulating and inspecting the list of server version tokens maintained by the plugin. The  VERSION_TOKEN_ADMIN  privilege (or the deprecated SUPER  privilege) is required to call any of the Version Token functions. •A server-side plugin named  version_tokens  holds the list of version tokens associated with the server and subscribes to notifications for statement execution events. The  version_tokens  plugin uses the audit plugin API to monitor incoming statements from clients and matches each client’s session-specific version token list against the server version token list. If there is a match, the plugin lets the statement through and the server continues to process it. Otherwise, the plugin returns an error to the client and the statement fails. •Version token lists are established per server (for example, to specify the server assignment or operational state). In addition, an application that communicates with a server can register its own list of tokens that indicate the state it requires the server to be in. An SQL statement sent by the application to a server not in the required state produces an error. This is a signal to the application that it should seek a different server in the required state to receive the SQL statement. •Version tokens can be locked. An application can use token locks to indicate to other cooperating applications that tokens are in use and should not be modified. •Version tokens are pairs consisting of a name that serves as a key or identifier, plus a value.