Monday, 14 September 2009

Performance Tuning - Question 067.

Which of these are not true about the high watermark of a data segment? (Choose two.)

A . Reset by a TRUNCATE statement.

B. Reset by a DELETE statement.

C . Recorded in the header block of the segment.

D. Recorded in the data dictionary.

Explanation:

Answer B and D: The high- water mark indicates the block in the table for which all blocks below it have been used, and all blocks above it have not been used; it is recorded in the segment header block. The TRUNCATE command resets the high- water mark to the minimum. The DELETE command does not reset the high- water mark.

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