RE: ** temp table or permanent
- From: A Joshi <ajoshi977@xxxxxxxxx>
- To: Igor Neyman <ineyman@xxxxxxxxxxxxxx>, pythianbrinsmead@xxxxxxxxx
- Date: Thu, 6 Jul 2006 14:01:46 -0700 (PDT)
Igor,
Thanks. got it. I think GTT (global temporary table) is better from memory
point of view since it will be kept out of memory if it is too big. So I do not
understand : What are the advantages of PL/SQL table over temproary table. if
any. Thanks
Igor Neyman <ineyman@xxxxxxxxxxxxxx> wrote:
If GTT fits in memory (no physical IO), why should it be slower than
PL/SQL table?
Igor
---------------------------------
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of A Joshi
Sent: Thursday, July 06, 2006 9:14 AM
To: pythianbrinsmead@xxxxxxxxx
Cc: oracle-l@xxxxxxxxxxxxx
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@xxxxxxxxx> 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@xxxxxxxxx> 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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