Re: Concurrency Issue -- Transaction Serialization

SAMINATHAN Thu, 07 Mar 2002 03:04:09 -0800

I don't have record for your question?.Perhaps i may not be doing the concurrent access also.

But what i want is very simple, say for an example

i have a record number 105, i have opened it for modification and am modifying.And in this situation if some one else try to

open that record for modifcation, i want to throw an exception.

With respect to JOnAs, i don't know what kind of Locking it is using. i guess Mr. JONATHAN is the right person

to answer for that.

The probelm is that i want to catch the SQL Exception and show to user that the record is getting modified by the

other person.

Expecting your valuable comments.

Thanks and Regards

Saminathan.

----- Original Message -----

From: Ramakrishna N

To: [EMAIL PROTECTED]

Sent: Thursday, March 07, 2002 4:08 PM

Subject: Re: Concurrency Issue -- Transaction Serialization

Hi,

How are you modifying the record concurrently ? I mean what have you done to achive it ? That is where the answer to this question is there, I believe.

      The Container will actually take care of Transactions(CMT). So one doesnt have to worry about all that.

     If the container is using Pessimistic way of concurrency control then, though you think you are modifying the record concurrently its not the case in reality. If the container implements Optimistic way of concurrency control then the concurrency is handled by the container which is transperent to the user.

       I dont know what kind of stratgey is being used by Jonas.

       Hope this helps.

Regards,

kris

-----Original Message-----
From: SAMINATHAN [mailto:[EMAIL PROTECTED]]
Sent: Thursday, March 07, 2002 2:47 PM
To: [EMAIL PROTECTED]
Subject: Concurrency Issue -- Transaction Serialization

Hi

      I am trying to stop the concurrent access of my entity bean.Let me first give the brief

We are using SQL Server 2000,Jonas 2.2.6 App Server and Swing Client.

We have a form that contains basically three button New , Modify and View .We will call the entity bean via session facade for the each operation.For New, ejbCreate() of entity will be called, modify -- ejbLoad() and ejbStore() will be called.

All are BMP beans and trasaction is Container Manged.

Now i have set in my Data access object 's update method

                Connection con = util.getConnection();

                Debug.println("**************$$$$$$$$$$$$$$$$$$$$$$$$****************");
                dbConnection.setTransactionIsolation(4);
                int iIsolationLevel2 = dbConnection.getTransactionIsolation();
                Debug.println("update Isolation Level-- AFTER SETTING   : "+iIsolationLevel2);

Here is the problem, i have set the isolation level -- 4 (TRANSACTION_SERIALIZABLE)

and try to modify the same record simultaneously and it is happening.

I don't understand why it is not throwing the sql exception?

Can any one help me??

Thanks and Regards

Saminathan.

Re: Concurrency Issue -- Transaction Serialization

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