Câu 3: C2090-612: DB2 10 DBA for zOS

When is a merge scan join a well performing access path?

1. A. When the number of qualifying rows of the inner and outer table are both large. — đáp án hiện tại
2. B. When the query references at least two dimensions and the STARJOIN subsystem parameter is 1.
3. C. When the number of rows in the outer table is small and the number of pages accessed in the inner table is small.
4. D. When the matching columns of the inner table are in a non-clustering index or the outer table has duplicate qualifying rows.