ISOLATION LEVEL

From: DBA Deepak <oracle.tutorials_at_gmail.com>
Date: Tue, 10 Jul 2007 14:39:28 +0530
Message-ID: <75aa80160707100209v5521b9f5g71ca815b722efbb5@mail.gmail.com>

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.

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Regards,

Deepak
Oracle DBA

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http://www.freelists.org/webpage/oracle-l Received on Tue Jul 10 2007 - 04:09:28 CDT