How Does the Phyiscal Location of Rows Affect Indexes?: Finding All the Red Sweets Part 2 скачать в хорошем качестве

How Does the Phyiscal Location of Rows Affect Indexes?: Finding All the Red Sweets Part 2

In part one of the red candy series, Chris compared the efficiency of using a index range scan and full table scan to access data. He found that a full table scan was more efficient when fetching more rows than there are table blocks. This analysis made a big assumption however. It worked on the presumption that there was no correlation between the order of candies in the document and which the bags they were in. In this episode tests this assumption. Chris looks at how the physical order of rows in a table can affect the efficiency of indexes on it. He discusses how Oracle tracks this via the clustering factor. ============================ The Magic of SQL with Chris Saxon Copyright © 2015 Oracle and/or its affiliates. Oracle is a registered trademark of Oracle and/or its affiliates. All rights reserved. Other names may be registered trademarks of their respective owners. Oracle disclaims any warranties or representations as to the accuracy or completeness of this recording, demonstration, and/or written materials (the “Materials”). The Materials are provided “as is” without any warranty of any kind, either express or implied, including without limitation warranties or merchantability, fitness for a particular purpose, and non-infringement.