Partial Aggregate Showplan Operator
Partial Aggregate is used in parallel plans. It applies an aggregation function to as many input rows as possible so that writing to disk (known as a "spill") is not necessary. Hash Match is the only physical operator (iterator) that implements partition aggregation. Partial Aggregate is a logical operator.
See Also
Tasks
How to: Display an Actual Execution Plan
Reference
Concepts
Logical and Physical Operators Reference
Displaying Execution Plans by Using the Showplan SET Options (Transact-SQL)