Re: Data Area Locking

[MWalter@xxxxxxxxxxxxxxx]

Put the *LOCK IN instruction into a loop and use the error indicator, to
exit the loop. Unless you have a process that keeps the lock on the data
area for a long time, this should only iterate a few times.

If using V5R2 or above, you could use the Monitor Opcode and try again from
there.

C                                    DOU        not *inoe
C          *LOCK             IN              myDataarea
OE
C                                    ENDDO

Thanks,

Mark

Mark D. Walter
Senior Programmer/Analyst
CCX, Inc.
mwalter@xxxxxxxxxx
http://www.ccxinc.com


                                                                           
             "Brown, Keith                                                 
             (MAN-Corporate)"                                              
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                                                                   Subject 
                                       Data Area Locking                   
             05/09/2005 02:30                                              
             PM                                                            
                                                                           
                                                                           
             Please respond to                                             
              RPG programming                                              
              on the AS400 /                                               
                  iSeries                                                  
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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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