Re: Oracle db optimizer

"ddf" wrote in message
news:da400539-f3af-412a-b852-c66346d195e9_at_googlegroups.com...

On Tuesday, May 20, 2014 3:40:10 AM UTC-6, Jack wrote:
> "joel garry" wrote in message
>
> news:609a4cc1-fd8c-4a1d-88aa-113c7d5df5f5_at_googlegroups.com...
>
>
>
> On Monday, May 19, 2014 5:59:52 AM UTC-7, Jack wrote:
>
> > "Jack" wrote in message news:sshev.40752$SH2.19490_at_uutiset.elisa.fi...
>
> >
>
> >This isn't really enough information to say, but for whatever reason your
>
> >BS table doing a full scan is a much better plan than a bunch of >nested
>
> >loops. One could guess the statistics or lack of statistics in the XE is
>
> >responsible for that, but better to know than guess. Here is one >simple
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> >methodology for giving us enough information to tell - and you may work
> >it
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> >out just following the steps. Ignore the formatting >advice, of course.
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> >http://oracle-randolf.blogspot.com/2009/02/basic-sql-statement-performance.html
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> >
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> >This all assumes you've gotten the basics from the performance tuning
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> >manual. Jonathan Lewis has a book that explains it in detail, highly
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> > >recommended.
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> >
>
> >jg
>
> >--
>
> >_at_home.com is bogus.
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> >http://www.microscope.co.uk/news/2240220895/Oracle-extends-reach-with-desktop-virtualisation-specialist
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>
>
> Thanks jg for your comment.
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>
>
> Not sooooo interested to read 27 pages report about plan.
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> Well, no hint available to fix it. (or _dbparameter ?)
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> So I made the logic more simple. Leaving some details away.
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> Some exceptions (and extraordinary exceptionals) are now not counted.
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>
>
> But hmm. db 11's costbased optimizer looks very good. No glitches found.
>
> Yet.

>To fix the problem you need to understand the problem and how Oracle
>arrived at the problematic plan to begin with. This should be a >'ready,
>aim, fire' situation, not the usual 'ready, fire, aim' business. That "27
>pages report about plan" really *is* worth reading, and the >understanding
>it can give you about your current situation could be invaluable.
>We all started at the beginning -- it's the best place to be when you want
>to understand where you are and what you need to do to go >elsewhere.
>David Fitzjarrell

Sorry David if I fixed it wrong. False extinction ;) I do have read those plans, enough.

This fix is according business needs.

It is very often that DBA does not have any sence of business needs and lack of industry sector knowledge. Received on Wed May 21 2014 - 10:13:40 CEST