RE: ** temp table or permanent

From: Igor Neyman <ineyman_at_perceptron.com>
Date: Thu, 6 Jul 2006 09:27:23 -0400
Message-ID: <F4C27E77F7A33E4CA98C19A9DC6722A2010FC29F@EXCHANGE.corp.perceptron.com>

If GTT fits in memory (no physical IO), why should it be slower than PL/SQL table?  

Igor

---

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of A Joshi Sent: Thursday, July 06, 2006 9:14 AM
To: pythianbrinsmead_at_gmail.com
Cc: oracle-l_at_freelists.org
Subject: Re: ** temp table or permanent

Mark,
  Yes. Optimize/rewrite query was done. Then it was split up. Iam on 8.1.7 so no UNDO and I cannot increase the rolback segment any more. apart from storgae and memory, I think there is a performance impact too if I increase the size of rllback segments.

   So now the question is whether global temporary table or PL/SQL table. I assume PL/SQL table is always faster than temporary table.

   I am avoiding permament table or materialized view since that will involve redo/undo and increase the time. Thanks for your help.

Mark Brinsmead <pythianbrinsmead_at_gmail.com> wrote:

        You seem to be jumping through a lot of hoops to solve a fairly straight-forward (sounding) problem.         

        Your first step should be to optimize / rewrite the query to perform less I/O and or execute more quickly.         

        Your second step should be to increase UNDO / Rollback as needed, within practical limits, of course.         

        After this, you might consider temporary tables (Global Temporary Table recommended) etc. or

        Materialized Views.         

        Of course, advice like this is easy to give when I know *nothing* of your specific situation. ;-)                           

        On 7/5/06, A Joshi < ajoshi977_at_yahoo.com
<mailto:ajoshi977_at_yahoo.com> > wrote:

		Hi,
		   I had a big query which was running out of rollback

so after some tuning i had to break it down in to two. from the first query i store the result in a temporary table and then use it for second part. it is still slow. i did not use permament table since that could involve rollback/redo. but still i will try to check it. i am also thinking of pl/sql table but if that always remains in memory then it could impact memory or sga. pl/sql table uses pga or OS memory but if paging swapping occurs then it would impact sga too. Will it always be faster than temp or permanent table? Can some one give feedback if you had similar experience. Thanks for help.                 

	-- 
	Cheers,
	-- Mark Brinsmead
	   Staff DBA,
	   The Pythian Group
	   http://www.pythian.com/blogs 


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Received on Thu Jul 06 2006 - 08:27:23 CDT