API Reference > C API Concepts > Concurrency Control

Concurrency Control
Concurrency in Eduction is handled using sessions. An instance of an EDKEngine is initialized with corresponding grammars for entity extraction. Each such engine can be associated with one or more sessions. All the sessions in the engine share the same grammars. The engine must be configured fully before any sessions are created.
After you create a session, an EdkError is thrown if you change the engine settings. However, each individual session can process many documents or streams. Each session maintains its state independent of others. Each engine must be associated with at least one session by default.