The Oracle Sponge

Oracle Data Warehouse Design and Architecture

Archive for April 25th, 2005

Thread about block sizes

Posted by David Aldridge on 2005-04-25

An interesting question from sejasp on blocks sizes … http://dba.ipbhost.com/index.php?showtopic=1512

A five-times improvement in i/o performance, just by changing a block size? It's the sort of thing that ought to be making the hairs on the back of your neck rise.

UPDATE: April 23rd

Well the thread has morphed into the issue of whether it is appropriate/rude/presumptious of a person to ask questions of the original poster in a forum thread.

My opinion, which I think I state pretty clearly there, is based on the following:

  • A person has asked a question in a public forum, requesting advice.
  • As their question stands, it offers the possibility of a number of different answers, and some of the answers may be inappropriate.
  • Erm … that's it.

The most appropriate answer for the situation may be, "I do not think that any action is required here … what you perceive as a problem does not in my opinion justify any corrective action." You know that's advice that I've given quite frequently. Here's some examples of questions to which the answer is "Do Nothing"

  1. My data warehouse application is not using bind variables … what should I do?
  2. I have a number of indexes with more than 120 extents … how should I reduce this?
  3. My buffer cache hit ratio has dropped below 99% to 97% … help!

So under these circumstances, can anyone tell me what is wrong with probing for more information? Especially when you are giving free advice.

UPDATE: 24th April

Thanks for the nice thoughts there, fellas. Much appreciated.

UPDATE: 25th April

Happy ending — see, I knew sejasp was a good bloke on account of being an Aussie. I have about nine great relatives over there (mostly poaching, but a little light larceny also).

Hey, just jokes fellas. Happy ANZAC day. (Is that appropriate? Is ANZAC day potentially a happy thing? comments welcome, as always)

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If …

Posted by David Aldridge on 2005-04-25

… the weather forecast says “50 degrees with chance of afternoon thunderstorms”, and you find it snowing at 3pm, then you probably live in Colorado Springs

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