KEEP Pool – What is Wrong with this Quote?

28 08 2011

August 28, 2011

The book “Oracle Database 11g Performance Tuning Recipes” is out of the alpha stage – if you bought the alpha version from Apress, you should now be able to download the finished book.  I am currently reviewing the book review notes that I started collecting when reading the alpha version, so that I may see if any problems I found in the alpha version of the book are also found in the final printed version of the book.  My final version of the book review for this book could be interesting… stay tooned (yes, an intentional typo).

One of the sections of the book that survived the alpha stage of the book is Recipe 3-2 Managing Buffer Pools, found on page 87.  The first paragraph under the Solution heading states the following (note that I removed a couple of sentences from the middle of the paragraph, so the words in [brackets] were added to paraphrase the other sentences):

“You can use multiple buffer pools instead of Oracle’s single default buffer pool, to ensure that frequently used segments stay cached in the buffer pool without being recycled out of the buffer pool…  For example, if you want a segment to be cached (or pinned) in the buffer pool, you must specify the KEEP buffer pool [when creating the segment].”

*** Note that this section of the book is NOT suggesting the use of multiple block sizes in a single database, but is trying to suggest why KEEP and RECYCLE buffer pools should be used in addition to the DEFAULT buffer pool.

What, if anything, is wrong with the above quote from the book?

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.