RE: Data Area Locking

["Joel Fritz" <JFritz@xxxxxxxxxxxxxxxx>]

Hmm...We do this all the time.  This may be pointing out the obvious,
but are you doing it in a loop?

e. g.

dou NOT %error;
    in (e) *lock data_darea;
enddo;
//code to use the data area value....

Among other things, we use this for order numbers. The probability of
contention for the data area is high. We've never had a problem.

Do you have ghost sessions?  Someone's pc crashes when the emulation
session has a lock on the data area or someone clicks the close box on
an emulation session.

BTW, if the id number is necessary, the program should halt if it's
impossible to get at the data area. 



> -----Original Message-----
> From: rpg400-l-bounces@xxxxxxxxxxxx
> [mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Brown,
> Keith (MAN-Corporate)
> Sent: Monday, May 09, 2005 11:31 AM
> To: 'rpg400-l@xxxxxxxxxxxx'
> Subject: Data Area Locking
>
> We use a data to maintain an unique ID number - Application
> RPG programs call a dedicated RPG program that uses the data
> area to generate a new ID.
> The RPG program to generate the ID uses the data area in the following
> manner:  1.) retrieve the data-area to import the current ID
> number 2.) increment the current ID number by one to generate
> a new ID and 3.) update the data-area for the new ID number
> 4.) release the data area.
>
> On occasion we get the following sequence of messages when
> the RPG program that locks the data-area is unable to execute
> the IN operation against the
> data-area:
> MCH5802       20     Lock operation for object &1 not satisfied.
> RNQ0431       99     Data area &6 was allocated to another
> process (C G D F)
> 
> The RPG program will go into MSGW until the RNQ0431 message
> is answered.  I have tried to use the Error Indicator and
> Error extender on the IN operation to prevent the message
> wait state be no such luck.  What can I do to prevent the
> programs from going into the message wait state when unable
> to allocate the data area?  I thought using the error
> indicator/extender on the IN operation would prevent the
> MSGW; much like what happens on database file I/O operations.
>
> Thanks,
> Keith
> --
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