Using Clustered Index.
This showplan message indicates that the query optimizer chose to use the clustered index on a table to retrieve the rows. The following query shows the clustered index being used to retrieve the rows from the table:
select title_id, title from titles where title_id like "T9%"
QUERY PLAN FOR STATEMENT 1 (at line 1). STEP 1 The type of query is SELECT. FROM TABLE titles Nested iteration. Using Clustered Index. Index : title_id_ix Forward scan. Positioning by key. Keys are: title_id ASC Using I/O Size 16 Kbytes for index leaf pages. With LRU Buffer Replacement Strategy for index leaf pages. Using I/O Size 16 Kbytes for data pages. With LRU Buffer Replacement Strategy for data pages.