Top N Sort Showplan Operator
Top N Sort is similar to the Sort iterator, except that only the first N rows are needed, and not the entire result set. For small values of N, the SQL Server 2005 query execution engine attempts to perform the entire sort operation in memory. For large values of N, the query execution engine resorts to the more generic method of sorting to which N is not a parameter.
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)