December 13, 2010
In the interest of interesting quotes, a quote that I found in the “Oracle Tuning the Definitive Reference Second Edition” book on page 539:
“But what is Oracle’s official position on multiple blocksizes? For Oracle metal-level customers, there is the Oracle Metalink system which provides the official position of Oracle’s own experts.
Metalink Note: 46757.1, titled Notes on Choosing an Optimal Db Blocksize, says that there are some benefits from having larger blocksizes, but only under specific criteria (paraphrased from Metalink):
- Large blocks give more data transfer per I/O call.
- Larger blocksizes provide less fragmentation, i.e. row chaining and row migration, of large objects (LOB, BLOB, CLOB).
- Indexes like big blocks because index height can be lower and more space exists within the index branch nodes.
Metalink goes on to say that multiple blocksizes may benefit shops that have ‘mixed’ blocksize requirements…”
What, if anything, is wrong with the above quote?
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.
Other pages found during a Google search of the phrase:
- http://forums.oracle.com/forums/thread.jspa?threadID=566662&start=30&tstart=15 (first posting in that OTN thread)
- http://jonathanlewis.files.wordpress.com/2008/07/ls2.pdf (230+ page OTN thread, hosted by permission – excellent discussion.)