BT Orchestrations Test

This refers to orchestrations that are not making progress but are not dehydratable, as when the orchestration is blocked waiting for a receive, listen, or delay in an atomic transaction.

A high value is desired for this measure. A low value or a steady decline in the value of this measure could indicate an execution bottleneck.

An orchestration can be discarded if the engine fails to persist in its state.

All failures encountered in orchestrations appear as exceptions.

If an orchestration does not include any CatchException shape for an exception, the exception causes the orchestration to be Suspended, but not resumable. This means that message and service instance tracking, or a WMI script, cannot recover the instance. However, you can save all messages associated with the Suspended (not Resumable) instance using tracking (or WMI script) for diagnostic and manual retry.

To diagnose the problem, use the Orchestration Debugger to see the last shape executed before the instance was suspended. You can also view exception details using the Orchestration Debugger.

Rehydration is the process of deserializing the last running state of an orchestration from the database.

The orchestration engine can be triggered to rehydrate an orchestration instance by the receipt of a message or by the expiration of a time-out specified in a Delay shape. It then loads the saved orchestration instance into memory, restores its state, and runs it from the point where it left off.

Dehydration is the process of serializing the state of an orchestration into a SQL Server database.

The orchestration engine might determine that an orchestration instance has been idle for a relatively long period of time. It calculates thresholds to determine how long it will wait for various actions to take place, and if those thresholds are exceeded, it dehydrates the instance. This can occur under the following circumstances:

• When the orchestration is waiting to receive a message, and the wait is longer than a threshold determined by the engine.

• When the orchestration is "listening" for a message, as it does when you use a Listen shape, and no branch is triggered before a threshold determined by the engine. The only exception to this is when the Listen shape contains an activation receive.

• When a delay in the orchestration is longer than a threshold determined by the engine.

The engine dehydrates the instance by saving the state, and frees up the memory required by the instance. By dehydrating dormant orchestration instances, the engine makes it possible for a large number of long-running business processes to run concurrently on the same computer. This implies that the larger the number and rate of dehydrations minimal will be the use of system resources.

A very large value could indicate a processing bottleneck.

Ideally, the value of this measure should be 0.

This is the current size of memory that this process has allocated that cannot be shared with other processes.

This is the current size of the virtual address space the process is using. Use of virtual address space does not necessarily imply corresponding use of either disk or main memory pages. Virtual space is finite, and the process can limit its ability to load libraries.