| PERFORMANCE OF A QUERY ; [message #307693] |
Wed, 19 March 2008 09:02  |
sispk6
Messages: 164
Registered: November 2006
Location: pakistan
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Senior Member |
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AOA // hI ALL
..
i was using a query , which was working all right having records in millions almost , but when i introduced a parameter , and used
nvl() function to handle that parameter , its working allright but the performance has decreased considerably , what should i use , will decode serve any better from response time point of view.
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| Re: PERFORMANCE OF A QUERY ; [message #307696 is a reply to message #307694] |
Wed, 19 March 2008 09:11  |
sispk6
Messages: 164
Registered: November 2006
Location: pakistan
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Senior Member |
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ya i do ,
but i wanted all the experts to share thier techniques that they used to improve performance during different scenario's. i have one scenario and three possible conditions.
1. use NVL
2. use decode
3. use nvl while creating parameter list.
i am looking for little thoeratical knowledge about improving performance .
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| Re: PERFORMANCE OF A QUERY ; [message #307697 is a reply to message #307693] |
Wed, 19 March 2008 09:21 |
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BlackSwan
Messages: 26766
Registered: January 2009
Location: SoCal
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Senior Member |
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>i am looking for little thoeratical knowledge about improving performance .
As opposed to 1st hand knowledge gained by doing actual benchmarks yourself?
The usual answer for Oracle when it comes to any performance question is, "It depends".
If there was a one size fits all solution, Oracle would hard code it into the DB engine.
[Updated on: Wed, 19 March 2008 09:21] by Moderator Report message to a moderator |
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| Re: PERFORMANCE OF A QUERY ; [message #307698 is a reply to message #307697] |
Wed, 19 March 2008 09:29 |
ThomasG
Messages: 3212
Registered: April 2005
Location: Heilbronn, Germany
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Senior Member |
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Perhaps the only general thing might be to try to avoid functions on the data side, like don't do
select number,name
from table
where number * 2 = 4;
but do
select number,name
from table
where number = 4 / 2;
so that the expression is calculated only once and the optimizer can use an index on number.
But the only real answer is "it depends" 
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