Along with Instance Query, Windows Server AppFabric also provides a default implementation of Instance Control Provider API for SQL Workflow Instance Store.
Instance Control commands are defined as a CommandType
enumeration, as shown in the following code snippet:
public enum CommandType { Suspend, Resume, Terminate, Cancel, Delete, }
Instance Control Provider provides an asynchronous and durable command execution mechanism. All the issued commands are stored in a command queue in an Instance Store. Workflow Management Service (WMS) owns the execution of these commands by picking them up from the Instance Store and executing them against the specified workflow instance, following the First-In-First-Out (FIFO) algorithm.
WMS places a lock for 65 seconds on the instance for which it has picked up a command. If the command is executed successfully, it gets deleted from the queue and the lock is released immediately. In case of a failure...