Optimizing Dimension and Cube Processing - SQL Server Analysis Services 2012 Cube Development - page 170

Process . Doing so opens the Process Dimension dialog, identical to that
available with SSMS, except the dialog lists all the chosen dimensions.
10. Execute the XMLA statement by pressing F5 and monitor what happens be-
hind the scenes using SQL Server Profiler (you can use the default Analysis
Services template within SQL Server Profiler ).
How it works...
SQL Server Profiler will report the following event subclasses during dimension pro-
cessing:
• Build processing schedule
• Execute SQL
• Read data
• Write data
• Build decode
• Build index
• Object created
• Commit
So running the process update on a dimension involves allocating Analysis Services
threads, executing queries against the relational data store, reading data, and sub-
sequently, writing to MOLAP storage, and building indexes prior to committing the
transaction.
If you look closely, SSAS also has an event subclass, object created , which
should more appropriately be named object updated . This is because we must
update each partition's indexes and aggregations to reflect changes in the dimension
data. You can scroll over to the ObjectName column within SQL Server Profiler to
see the list of affected partitions.
Tip
If you check the SELECT statements submitted to the relational database engine,
you will find that they're not exactly identical to the dimension table / view defin-
ition. Analysis Services writes a separate query for each attribute and retrieves