Oracle 10g Release 2 Parameter Dependencies

A wise man once said that one of the clear signs of Compulsive Tuning Disorder (CTD) was an extensively tweaked set of initialization parameters. While it's probably a stretch to say that very few parameters needs to be changed on the creation of a new instance we do seem to be moving in the direction of relying more on default values (IMHO).

Now, the initialisation parameters for 10gR2, indeed for any version, are a rats nest of inter-dependencies. Change X, and Y and Z also change. Usually the dependency is that the default value is determined either in part or in whole by the value of one or more other parameters. To help understand this and because a picture is worth a thousand words, I've knocked up a couple of network diagrams (or whatever you want to call them) to illustrate this, so that you can see these relationships at a glance.

In some cases the relationship is very complex, such as that between large pool size and DBWR IO slaves. In other cases the value of one parameter establishes an upper or llower limit for another, or X is affected only by Y dependent upon values of Z. I've used different connector styles to try and illustrate this.

It's still a work in progress mind you, but I thought I'd throw out an initial version for comments.

Future enhancements …

  1. Code the parameters by their dynamic/static type
  2. Include links back to the documentation
  3. A triple-check of the accuracy
  4. Add other types of inter-dependency, such as "X value used only if Y value is set to …"
  5. Erm …
  6. Anything else that people can think of.

Disclaimer: these are only as accurate as (i) the documentation (ii) my reading of the documentation (iii) my illustrative capabilities. Read the documentation for validation.

Click on the little pictures to get the full-size image, and feel free to make suggestions and whatnot.

NLS Parameters

General Parameters

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8 thoughts on “Oracle 10g Release 2 Parameter Dependencies

  1. hello, i’m bill and i’m a complusive tunner.;-)

    and thanks for the “map” makes more snese to me when i can see it layed out that when i try and follow things through the documentation wasteland.

  2. I think I’ll standardize on “s” :D

    Well my next version includes every documented parameter on a single page, with links to the docs for all of them (when published as an HTML page) and more categories — “RAC”, “Obsolete/Deprecated”, “Audit”, “Optimization” etc.

    It’s turning out to be a pretty interesting learning exercise, though marking the relationships between the parameters is a little challenging as I have to link those that are generally related to each other, those pairs for which only one can be set, pairs for which setting “A” disables “B” and whatnot.

    Good clean fun, in other words.

  3. Great Idea!
    Ideally what I see, what to add in future:
    – Possibility to turn on/off the layers by categories.
    – Active values – somewhat that mimics Oracle’s behaviour when you change one parameter how others will change (and higlight them). Something like formulas in MS Excel (or Supercalc). I know, it would be a challenge to reverse engineere these formulas. Also they most likely are specific to versions/platforms.

    Anyway – it is a very good idea!

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