December 8, 2010
While reading the “Oracle Tuning the Definitive Reference Second Edition” book I found a handful of interesting suggestions regarding Oracle wait events. For instance, page 406 of the book states that:
“Excessive db file sequential read waits on an OLTP database might indicate a suboptimal disk subsystem or configuration issues with the disk array. High I/O waits on the db file scatter read waits associated with large-table full-table scans may not always indicate a problem, but they are most commonly found on these kinds of databases:
- Data warehouse and Decision Support applications
- 32-bit Oracle systems with SGAs of less than 1.5 gigabytes
- Databases that do not have enough buffer cache space to cache their working set of frequently referenced objects”
Keeping in mind that the book is printed after the release of Oracle Database 188.8.131.52 (and possibly 184.108.40.206 for some operating system platforms), what, if anything, is wrong with the above quote? See example 1 on this blog article for a “Top 5 Timed Events” report section that is similar to what is found on page 406 of the book.
While my review of the book only provides an in-depth technical review of the first 200 pages of the book, this blog article series will dig into some of the pages that were not specifically included in the review.
The point of blog articles like this one is not to insult authors who have spent thousands of hours carefully constructing an accurate and helpful book, but instead to suggest that readers investigate when something stated does not exactly match what one believes to be true. It could be that the author “took a long walk down a short pier”, or that the author is revealing accurate information which simply cannot be found through other resources (and may in the process be directly contradicting information sources you have used in the past). If you do not investigate in such cases, you may lose an important opportunity to learn something that could prove to be extremely valuable.
As I stated in a comment in the earlier blog article, I would like to clarify that my review on the Amazon site is not intended to suggest that people should not buy the book. As the publisher’s website states that the book is written for senior Oracle DBAs, I suggest that senior DBAs, Oracle Certified Masters, and other people who are able to research the book’s contents *should* buy the book and post reviews of the book that highlight specific content of the book indicating whether or not that content is correctly stated. Such feedback will be a benefit to the Oracle community, and could help to improve Oracle Database books that are published in the future. I think that we need to keep a positive outlook in order to see things improve.
Other pages found during a Google search of the phrase:
- Page 713 of the previous edition of the book