Re: RPGLE Stored Procedures and Thread Safety

[dfeather@xxxxxxxxxxxxxxx]

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.

        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. 
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. The RPGLE 
program does not update any files. 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. 
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#HDRH
>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)
> mailing list To post a message email: JAVA400-L@xxxxxxxxxxxx
> To subscribe, unsubscribe, or change list options,
> visit: http://lists.midrange.com/mailman/listinfo/java400-l
> or email: JAVA400-L-request@xxxxxxxxxxxx
> Before posting, please take a moment to review the archives
> at http://archive.midrange.com/java400-l.

-- 
mfG

Dieter Bender


DV-Beratung Dieter Bender
Wetzlarerstr. 25
35435 Wettenberg
Tel. +49 641 9805855
Fax +49 641 9805856
www.bender-dv.de
_______________________________________________
This is the Java Programming on and around the iSeries / AS400 (JAVA400-L) 
mailing list
To post a message email: JAVA400-L@xxxxxxxxxxxx
To subscribe, unsubscribe, or change list options,
visit: http://lists.midrange.com/mailman/listinfo/java400-l
or email: JAVA400-L-request@xxxxxxxxxxxx
Before posting, please take a moment to review the archives
at http://archive.midrange.com/java400-l.