Microsoft Office Tutorials and References
In Depth Information
Understanding Operational Concepts
Figure 3-8 shows the initial state of the session after the workbook is opened (State 1), followed by the
states after two additional operations of setting values into cells are performed (State 2 and State 3).
A1 = 1
A2 = 2
The session state is maintained in memory on the ECS machine. In a scaled-out configuration (when
there are multiple ECS machines), all requests for a session will always be routed to the same ECS
machine — the one that contains the session state.
Shutting down the ECS process causes all the users of that ECS machine to lose the session state.
Therefore, you should not shut down the ECS process while there is activity on the system. Note that
the ECS runs in the context of the IIS process, and, therefore, the IIS process recycling settings affect the
ECS. Set IIS to recycle when there is no user activity.
When working with the EWA, the browser keeps the session ID and sends it to the server in every
request, to identify the session that will process the request.
Operations are requests that the user performs on workbooks. Examples of operations are opening and
closing workbooks, getting values from cells and setting values into cells, calculating the workbook,
refreshing data, filtering and drilling a pivot table, filtering and sorting a table, and finding a value in
The typical flow of a request is as follows:
The user sends the request from the client machine to the WFE, which forwards the request to
The ECS performs the request, updates the state of the workbook in the session, and returns the
result back to the WFE. In the case of the EWA, the result typically contains the new range to be
The ECS does not allow a user to perform more than one request per session at any given time, except
for the following operations that can be performed in parallel in a session:
Getting values from the workbook
Getting charts from the workbook
Closing the workbook