December 21, 2009
Frustrated by some of the confusing and contradictory information I have encountered on the Internet over the years, I put together a “cheat sheet” to help identify useful information. The “cheat sheet” lists several questions that one might consider when reviewing books and web articles prior to changing parameters (or implementing other changes) based on the information found in those sources:
- Is a specific Oracle release mentioned in the book or article? What was true, or thought to be true, with release 8.0.5 might not be true or even a good idea with release 18.104.22.168.
- Does the article have a publication date, and is there a revision history that identifies the date and what modifications were made to the article? Articles which change from one day to the next without knowing what changed, and why the article changed, are difficult to use as justification for changes to the initialization parameters.
- Are there any articles by other authors on the Internet which agree with the author’s suggestions or sharply disagree with the author’s suggestions? If Oracle’s official documentation strongly disagrees with the contents of the article, which of the two sources are correct? Should the advice be deemed an over-generalization which worked as a fix for a one time problem that is now advertised as something all DBAs should do as a first step in performance tuning?
- Is there reproducible evidence that supports the claims made? Or, is the majority of the justification similar to “I have seen it a 100 times” or “a DBA at a fortune 50 company said to do this” or “I have been doing this for 25 years, and you should too”?
- Does the parameter actually control the behavior which it is purported to control, and are there any potential side effects from modifying the parameter?