Serializable isolation level behavior question

Hi,  

We are testing concurrency performance and trying to isolate the issue using sqlplus and some dummy tables and need some clarification. Following is the scenario:  

Session 1 (isolation level read committed)  

Insert into dd values(1);

Commit;

Insert into dd values(2);

Commit;  

Session 2 (isolation level serializable)  

Set transaction isolation level serializable  

Select * from dd; (2 rows returned at this point)  

Now issue another insert from session 1

Insert into dd values(3);

Commit;  

Select * from dd; (still return 2 rows)  

Truncate table dd; (issue implicit commit)

Select * from dd; (This should still shows 2 rows as read data from rollback segments since in serializable mode, it need to show the pre-image before the truncate but it is showing 0 rows)  

Is this expected behavior that in second session it returns 0 rows and not 2 rows?  

Thanks

--Harvinder
 

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http://www.freelists.org/webpage/oracle-l Received on Mon Oct 16 2006 - 15:36:16 CDT