Friday, 10 July 2009

Performance Tuning - Question 001

Which of these is not a performance advantage of large table extents?

A . It is possible to read the entire extent map with one I/O.

B . The object has space pre-allocated for future growth.

C . Dynamic extent allocation is reduced with large extents instead of small extents.

D. Some of the space may be wasted until the object grows into the large extents.

Explanation:

Answer D: If you size segments so that they don't extend frequently, then you will have unused space in the extents until the objects become fully populated. This wasted space is not a performance advantage and probably is not a disadvantage either.

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