Clarification on Clustered index scan and Clustered Index Seek
Execution plan still shows ClusterIndex Seek why?


The initial seek down the b-tree is to find the first row where CustomerID &gt;= 1.

From that point on, the storage engine remembers the current scan position, and returns the next row in index order that qualifies each time a row is requested by a parent plan operator. The scan comes to an end as soon as a row is encountered that does not match the predicate CustomerID &lt;= 70000.

The effect is that the 'seek' is an initial seek, followed by a partial ordered scan of the index.

This is usually more efficient than scanning the whole index, even where 90% of the rows are expected to qualify. The key point to get straight in your mind is that a separate b-tree seek is not performed for each row.