MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6
Version Tokens is based on a plugin library that implements these elements:
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.
A set of user-defined functions (UDFs) provides an SQL-level
API for manipulating and inspecting the list of server
version tokens maintained by the plugin. The
SUPER
privilege is required
to call any of the Version Token UDFs.
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.