Re: ISOLATION LEVEL
- From: "Niall Litchfield" <niall.litchfield@xxxxxxxxx>
- To: oracle.tutorials@xxxxxxxxx
- Date: Tue, 10 Jul 2007 11:58:04 +0100
Where does your requirement/code come from. Is your code not a logical
transaction? If so why do you need to see wrong/old data at later stages. If
it is a logical transaction then make it a single transaction and you'll
only see consistent data.
Something doesn't sound quite right but without seeing either your code or
your requirements it's somewhat tricky to tell.
On 7/10/07, DBA Deepak <oracle.tutorials@xxxxxxxxx> wrote:
Hi All,
Have a doubt on transaction isolation.
My requirement is to query several tables several times inside a piece of
code. The data needs to be consistent across multiple queries. The
underlying tables are subjected to change during the execution of the piece
of code.
I have two options to be used inside my piece of code to achieve
consistent/repeatable reads.
1> to use SET TRANSACTION READ ONLY;
2> to use ALTER SESSION SET ISOLATION_LEVEL=SERIALIZABLE;
My question is which option is preferable and why? Is there any
performance issues with one of these in the above mentioned scenarios?
Need your valuable feedback.
--
Regards,
Deepak
Oracle DBA
--
Niall Litchfield
Oracle DBA
http://www.orawin.info
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