Re: RPGLE Stored Procedures and Thread Safety

Dieter,
        Thanks for all your help and patience, and thanks to everyone else 
who piped up. Have a good day!


Dan Feather





Dieter.Bender@xxxxxxxxxxx (Dieter Bender)
Sent by: java400-l-bounces@xxxxxxxxxxxx
07/08/2003 09:59 AM
Please respond to Java Programming on and around the iSeries / AS400 

 
        To:     Java Programming on and around the iSeries / AS400 
<java400-l@xxxxxxxxxxxx>
        cc: 
        Subject:        Re: RPGLE Stored Procedures and Thread Safety


Dan

there is no confusion at all and nothing to apologize.

On Tuesday 08 July 2003 15:31, you wrote:
> Hi,
>         Thanks to all for the information. I think I may have 
incorrectly
> described the situation. I "said" several multi-threaded applications.
> What I was "thinking" was several Websphere applications... not exactly
> the same thing I know, and I apologize. My typing wasn't keeping up with
> my thoughts, or vice versa.
>
>         So, that being said, as far as synchronizing on the JDBC
> Connection object, I don't think that is necessary, since I am getting a
> connection from the Websphere connection pool, using it, and putting it
> back for each call. Even with multiple-requests getting serviced by the
> same app at the same time, they wouldn't all be using the same 
Connection
> object, and I am certain my Java code is thread -safe. So I think it is
> safe there.

exactly

>
>         I am beginning to think everything will be fine. I believe, and
> correct me if I am wrong, every call will be serviced by a different 
job.

exactly 

> That being the case, I think I will be able to make multiple calls to 
the
> RPGLE stored procedure, and since they are each running in a different
> job, I shouldn't have to worry about their thread safety. 

exactly

The RPGLE
> program does not update any files. 

that would make no diffrence

The only concern I would have is the
> output parameters possibly getting hosed. But, if I understand things
> correctly, that problem goes away if they are running in different jobs.

only one problem might be left: the jobs are reused and the stored 
procedure 
might stay activated and reinitialisation might be an issue.

Dieter

> Again, I apologize for the confusion, and thank you very much for your
> help.
>
> Dan Feather
>
>
>
>
>
> Dieter.Bender@xxxxxxxxxxx (Dieter Bender)
> Sent by: java400-l-bounces@xxxxxxxxxxxx
> 07/08/2003 02:23 AM
> Please respond to Java Programming on and around the iSeries / AS400
>
>
>         To:     Java Programming on and around the iSeries / AS400
> <java400-l@xxxxxxxxxxxx>
>         cc:
>         Subject:        Re: RPGLE Stored Procedures and Thread Safety
>
>
> Hi,
>
> there is no need for this, the JDBC Environment is not Multithreaded and
> things get worse with this Compile option. The access to procedures is
> synchronized on the modules and it doesn't work safe for exported
> variables.
>
> Dieter
>
> On Monday 07 July 2003 20:33, you wrote:
> > Is your RPG procedure defined with THREAD(*SERIALIZE)??
> >
> > Here's an excerpt from the ILE RPG reference manual:
> >
> >     The THREAD(*SERIALIZE) keyword indicates that the ILE RPG module
> >     created may run in a multithreaded environment, safely.
> >
> > Here's a link to the full text:
> > http://publib.boulder.ibm.com/iseries/v5r2/ic2924/books/c092508419.htm#HD
> >RH THREAD
> >
> > On Mon, 7 Jul 2003 dfeather@xxxxxxxxxxxxxxx wrote:
> > >         I have written an RPGLE program that utilizes a service
>
> program
>
> > > for calculating the price of a given item. I have written this 
program
>
> so
>
> > > that I can use it as a stored procedure, which I plan on calling 
from
> > > several multi-threaded applications. In the past I ran into problems
>
> with
>
> > > stored procedures that returned result sets, and I eventually found
>
> out
>
> > > via links provided by several nice people on this list that the
>
> cursors
>
> > > opened in those stored procedures are not thread safe. So, when I
>
> started
>
> > > developing this new stored procedure I went looking for information 
on
> > > the thread-safety of RPGLE stored procedures, and I have not
>
> successfully
>
> > > found information leading to a conclusion. I checked the usual
>
> resources
>
> > > (google, ibm.com, Redbooks, mid-range archives, etc.), and ran some
>
> tests
>
> > > of my own, but I want to be more certain than I am that RPGLE stored
> > > procedures are thread safe. So, I was wondering if anyone here knew 
of
>
> a
>
> > > source of information on this specific subject that I may have 
missed,
>
> or
>
> > > knew off-hand if they were thread safe. Thanks in advance!
> >
> > _______________________________________________
> > This is the Java Programming on and around the iSeries / AS400
>
> (JAVA400-L)
>
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-- 
mfG

Dieter Bender


DV-Beratung Dieter Bender
Wetzlarerstr. 25
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Tel. +49 641 9805855
Fax +49 641 9805856
www.bender-dv.de
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