E you can update data from this block when the

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Unformatted text preview: from this block when the PCTUSED threshold is crossed. Oracle 8, DBA Certification Exam Guide, Jason S. Couchman, p. 471 Chapter 10: Managing Database Use QUESTION 46: The extent sizes of a table should be _____ to improve performance of the table scans. A. All equal B. No larger than five times DB_BLOCK_SIZE C. Equal to the size of the biggest possible row D. A multiple DB_FILE_MULTIBLOCK_READ_COUNT Answer: D Explanation: Answer D is correct. The extent sizes of a table should be multiple DB_FILE_MULTIBLOCK_READ_COUNT parameter in initSID.ora file to improve performance of the table scans. Incorrect Answers: A: The equal extent sizes will not improve performance of the table scans, because for full scans you need to try keep data in less extents as possible. B: Each extent contains at least 5 data blocks, so if you will use no larger than 5 times DB_BLOCK_SIZE it will be minimal possible size of extent. To store data you will need a lot of extents in this case, it will decrease table scans performance. Actualtests.com - The P...
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This document was uploaded on 03/08/2014.

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