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Re: Implement Parallel Processing on DB Warehouse

From: Mladen Gogala <>
Date: Wed, 11 Feb 2004 10:13:11 -0500
Message-ID: <>

On 02/11/2004 09:55:25 AM, "Freeman, Donald" wrote:
> "Flushing is harmful"
> ?? In response, I am flushing the shared_pool on this test instance
> so
> =
> that I can get baseline timing info. I understand that if I do it as
> a
> =
> matter
> of course I am losing the benefit of having parsed, reusable code and
> =
> data already in memory.

Data will stay in memory, but parsed, reusable code and data dictionary entries will not. That is, generally speaking, why flushing is considered harmful.

> "Hint is ignored because of incorrect syntax"
> That's what I get for using a bargain table book for reference. I =
> thought I would be able to tell when something wasn't appropriate for
> a =
> 9i database. I tried your suggestions and it worked although I didn't
> =
> get the results I wanted. Once I parallized that index I more than =
> quadrupled the time it took to perform that query from about .4
> seconds =
> to 1.7 seconds. It doesn't look like this is something I can throw
> at
> =
> the database but will have to implement on a case by case, query by =
> query basis. I was probably a little unrealistic to project '1 week'
> to =
> implement parallelism <g>. I've been working on this one little test
> =
> statement nearly that long.=20

Well, CBO became a smartass with release 9.2 and if it isn't choosing parallel path, there might be a good reason for it.

> "With how many zeroes do you spell "grateful"?"
> As many as you want! $0000000000000000000000000000. With zeros you
> can =
> never have enough! I appreciate the time you took to answer my
> question =
> and, of course, would help you move furniture if called upon. It's
> not =
> likely that you would ever need Oracle advice from me. I rely on
> these =
> lists extensively for answers but try to do as much of my homework as
> I =
> can before I use up bandwidth asking for an easily obtained answer.
> I've =
> only been on this list for about a week but I believe I recognize
> some
> =
> of the names from the IOUG forum on Compuserve from about five years
> =
> ago.=20

I was just kidding. Don't take me too seriously, please.

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Received on Wed Feb 11 2004 - 09:13:11 CST

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