Re: problem multi-threading a stored procedure

[TitanRebel <TitanRebel@xxxxxxxxxxx>]

Thanks for the reply.  The only way I know to use a seperate job for 
each user, is to create a seperate Connection for each user.  Am I 
correct?  Anyway, I am in the process of rewriting this so that a 
Connection will be created for each session.  I will store the 
Connection object and the CallableStatement objects in the user's 
session.  Now, I'm worried about sessions that timeout.  I will provide 
a logout button that will invalidate the session and close statements 
and sessions.  But, I know my users...they will ignore the logout button 
and just close the browser.  So now I will have sessions that timeout. 
How will this effect the connection to the iSeries?  I assume once the 
session is invalidated any objects stored in that session are marked for 
garbage collection.  If a connection or statement get garbage collected 
will that "hang" the job on the AS400?  Or, am I being too paranoid?

SRamanujan@xxxxxxxxxxxxxxxxxx wrote:

> I think, in this scenario, the job i.e. qzdasoinit being the same, there
> is no uniqueness to the different user.  That perhaps is the reason, the
> 2nd user gets 1st user's results.   I am still not sure how this should
> work, since the 1st user responses will never be picked up or passed by
> any job unless you introduce another control that tracks the user and
> sends the result back to the cookies or user session or something.  Also
> what if the same user signs in 2 different sessions?
>
> When we came across the design issue, we used a different job for
> different user, however when the user is signed on, all requests from
> that user will pass through the same thread.  This eliminated the
> mix-up.  This worked out ok for us though. 
>
> But I believe there is a 3rd party plug-in that can handle same thread
> to be used for different users since it keeps track of the user signed
> in, somehow.  
>
> Thanks,
> Sudha
>
> -----Original Message-----
> From: TitanRebel [mailto:TitanRebel@xxxxxxxxxxx] 
> Sent: Friday, March 07, 2003 1:24 PM
> To: java400-l@xxxxxxxxxxxx
> Subject: problem multi-threading a stored procedure
>
> I am having a problem with a stored procedure.  Hopefully, someone has 
> experience with this.  Here is my environment.
>
> - Jakarta Tomcat 4.0.4 running on iSeries.
> - Servlet calls a stored procedure to get list of results.
> - Stored Procedure is written in RPG, running on same iSeries.
>
> Everything works great when there are not simultanious requests to the 
> same Stored Procedure.  If two users request the results at 
> approximately the same time, one of them doesn't get any results.  From 
> what I can tell, the second person to request the results get the 
> results, and the first person gets none.
>
> I have verified that the Servlet (as expected) is being executed in two 
> seperate threads.  The Connection and the CallableStatement are declared
>
> as fields (class level variables).  The ResultSet is a local variable 
> that immediately gets turned into an ArrayList which is passed to a JSP 
> page for display.  So, I am using the same Connection for every user, 
> and calling the "executeQuery()" method on the same CallableStatement.
>
> Can anyone see what is wrong?  My guess is that this connection is being
>
> serviced by the same QZDASOINIT prestart job, therefore it is 
> technically the same job that is calling the Stored Procedure each time,
>
> and that is why it can't handle multi-threading.  Does anyone know how 
> to get around this?  Should I create a seperate Connection object for 
> each user?  That seems ineffecient.
>
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