Microsoft Office Tutorials and References
In Depth Information
In addition to using the built-in Excel functions, the ECS supports user defined functions (UDFs).
The trusted UDF-managed assemblies are custom code called from workbooks. You should have
an understanding of how each UDF can impact server resources. (Chapter 14 provides further
information about the UDF feature.)
Workbooks can be authored to calculate in automatic or manual mode. An automatic calculation
workbook is very convenient, but it may also perform unnecessary calculation operations. You
might want to set the calculation mode to manual for workbooks with longer calculation times.
This can serve as a real convenience to workbook consumers, because they won’t have to wait
for a calculation operation to finish unless they initiate the operation themselves. The ECS also
provides an administration feature that allows you to set the calculation mode at the trusted file
location level, overriding the workbook’s calculation mode. (Chapter 7 provides additional
You can further control the behavior of the automatic calculation mode for workbooks with the
Volatile Function Cache Lifetime setting for each trusted file location. You can allow workbooks
to use the automatic mode for calculations, and allow multiple users of the same workbook to
share the calculation results. (Chapter 7 provides additional details.)
The amount of formatting applied to the workbook and its contents can increase the size of a workbook
as well as the CPU usage. Consider the following:
Formatting increases the size of the response, which must be sent to the client when rendering a
workbook using the EWA, or when providing a formatted data response to an API getrange()
call, for example.
By default, the EWA Web Part renders 75 rows and 20 columns. You can configure the number
of rows and columns for each EWA. As the grid size increases, so does the response time, and
the effect of the formatting becomes more evident. Additional load will be present on the WFE
as the grid size increases.
Conditional formatting that must be evaluated by the ECS has a direct impact on the capacity of
the ECS in terms of CPU.
Another aspect of the workbooks to consider is the frequency with which the workbooks will be
modified in the ECS trusted location. When the ECS gets an open workbook request, the workbook in the
trusted location is checked to determine if it is newer than the copy in the ECS workbook disk cache.
Any time an update is found, a new copy of the workbook is loaded into the workbook disk cache and
into the memory of the ECS process.
Take into consideration not only how often workbooks will get updated, but also how frequently they
will be used. For example, users shouldn’t be updating a workbook that is used by a dashboard as a
home page for a large number of users during periods of high traffic.
The designers and consumers of the workbooks should play a big role in your capacity planning. The
more you can learn about their intentions, the more you will be able to plan your deployment to meet
the capacity expectations for your system. By proactively using the various administrative configuration