Clustered Index Scan Showplan Operator
The Clustered Index Scan operator scans the clustered index specified in the Argument column of the query execution plan. When an optional WHERE:() predicate is present, only those rows that satisfy the predicate are returned. If the Argument column contains the ORDERED clause, the query processor has requested that the output of the rows be returned in the order in which the clustered index has sorted it. If the ORDERED clause is not present, the storage engine scans the index in the optimal way, without necessarily sorting the output.
Clustered Index Scan is a logical and physical operator.
.gif "Clustered index scan operator icon")
Graphical execution plan icon
Examples
The following example queries a table that has a clustered index. The output of the execution plan shows that the query optimizer uses the Clustered Index Scan operator to retrieve the specified rows.
USE AdventureWorks;
GO
SET NOCOUNT ON;
GO
SET SHOWPLAN_ALL ON;
GO
SELECT DISTINCT TransactionType
FROM Production.TransactionHistoryArchive;
GO
SET SHOWPLAN_ALL OFF;
GO
The execution plan output of the Clustered Index Scan operator appears below.
PhysicalOp
-----------------------------------------------------------------------
Clustered Index Scan
Argument
-----------------------------------------------------------------------
OBJECT:([AdventureWorks].[Production].[TransactionHistoryArchive].[PK_TransactionHistoryArchive_TransactionID])
See Also
Tasks
How to: Display an Actual Execution Plan
Concepts
Logical and Physical Operators Reference
Clustered Index Structures
Displaying Execution Plans by Using the Showplan SET Options (Transact-SQL)
Help and Information
Getting SQL Server 2005 Assistance
Change History
| Release | History |
|---|---|
17 July 2006 |
|