Using Trace to Monitor and Audit Analysis Services - Microsoft SQL Server 2008 Analysis Services - page 773

(that is, when all the attributes have been processed), SQL Server Profiler will show a
Progress Report End .

Internally a dimension-processing operation spawns a processing job for every attribute in
the dimension. These processing jobs generate the same events—Pro gress Report Begin
and so on. Most of the time the processing of one attribute can run in parallel to the
processing of other attributes. When one attribute is related to another, the second one is
processed after the first one. For example, because all the attributes are related to the key
attribute of the dimension, directly or indirectly, the key attribute is processed last.

Take a look Figure 38.8, which shows the steps that are typically reported during the
processing of a single dimension attribute. Not all of these steps will necessarily be
executed during the processing of a dimension attribute, so you might not see events asso-
ciated with some of these steps in SQL Server Profiler. For example, only a grouping
attribute needs to go through the discretization step. Another example: Only for attributes
with a large number of members does the Analysis server need to create groups during
processing. For such big attributes, you would see only Progress Report events with
GroupData and GroupDataRecord subclasses.

ExecuteSQL

ReadData GroupData GroupDataRecord

WriteData

Discretize

WriteDecode

BuildDecode

BuildIndex

FIGURE 38.8

The trace of processing of a dimension attribute.