how to avoid a "data set not found"

jctgf · Active User Joined: 04 Nov 2006 Posts: 109

Hi,

I have a cobol program that reads a data-set that sometimes hasn't yet been created when the program runs.

the data-set is not that important.

in this case, the program should simply go on with no damage for the application.

my problem is:

when a steps starts and it references a data-set that doesn't exist, the job abends promptly.

the data-set doens't have to be effectiveley used by the program. the job abends before the data-set is opened by the program.

is it possible to cause Z/OS only to check the data-set existence when my program issues an OPEN command, please?

Thanks.

expat · Posted: Fri Dec 18, 2009 5:38 pm

Does it issue an ABEND or does it fail with a JCL error.

Basically, IMHO, what this comes down to is just plain poor planning and implementation. Is it really that difficult to write JCL that you know will work for at least 99% of the time because the files that are required are actually available.

Escapa · Posted: Fri Dec 18, 2009 5:39 pm

jctgf · Active User Joined: 04 Nov 2006 Posts: 109

this is a very particular case.

what I mean is:

is there a jcl parameter - like free=close, defer and so on - that would make ZOS only check the data-set existence when I open the file?

thanks a lot.

dbzTHEdinosauer · Posted: Fri Dec 18, 2009 5:43 pm

jctgf · Active User Joined: 04 Nov 2006 Posts: 109

the job abends with:

IEF212I J948JT61 EVTPTST6 ARQA - DATA SET NOT FOUND.

the job is critical and can't be postponed.

i'd like to dynamically check if the file exists.

if it doesn't, i wouldn't use (open, read, close) the file and this way the abend would be avoided.

my problem is: even if I don't open the file, ZOS checks it's existence and abends the job.

what I need is to say to ZOS "don't check the file existence until I open the file".

is it possible, please?

thanks.

Robert Sample · Posted: Fri Dec 18, 2009 6:02 pm

jctgf: you could dynamically allocate the file using BPXWDYN in your COBOL program so there would not be a DD statement for the file. How to do so has been extensively covered in other topics so if you search this forum for BPXWDYN you can find everything you need to use it.

expat · Posted: Fri Dec 18, 2009 6:15 pm

expat · Posted: Fri Dec 18, 2009 6:27 pm

dbzTHEdinosauer · Posted: Fri Dec 18, 2009 6:28 pm

expat · Posted: Fri Dec 18, 2009 6:29 pm

vasanthz · Posted: Fri Dec 18, 2009 6:33 pm

Hi,
As a temporary fix,
Probably you could add a JCL step to determine if the dataset exists and based upon the return code, you can execute the COBOL step with the "created" file or a similar dummy file.

You may have to allocate a new dummy file though.

Garry Carroll · Posted: Fri Dec 18, 2009 6:49 pm

vasanthz · Posted: Fri Dec 18, 2009 6:57 pm

vasanthz · Posted: Fri Dec 18, 2009 6:59 pm

expat · Posted: Fri Dec 18, 2009 7:09 pm

vasanthz · Posted: Fri Dec 18, 2009 7:17 pm

jctgf · Active User Joined: 04 Nov 2006 Posts: 109

Hi,

Thanks for the interest.

The situation is the following:

The system has a primary goal and also provides a secondary functionality: to detect and discard duplicate records sent to be processed.

Discarding duplicate records isn't the system main goal.

This functionality was implemented a few years ago and sort of "caught on". A few problems have been avoided because of this service.

The problem is that this functionality is very expensive and, sometimes, may cause serious delays in the processing.

Recently we had a major delay because the file that makes possible for the system to detect duplicate records wasn't available. The job that maintains this Vsam file abended and a lot of time was taken to have the problem solved.

Meanwhile, other jobs remained in the "waiting schedule" status. Everything came to a complete stop.

It’s a set of complex jobs that run at every 2 hours. Given that the Vsam file was out of service, a huge "traffic jam" was formed.

Every day we have a deadline - or a "dead-hour" - to process a lot of jobs. The entire thing almost failed to be processed in time because – again - the Vsam dataset was unavailable.

The night staff was forced to suppress its use by using asterisks (*) in the main program. The thing then proceeded without having the Vsam file operational.

If they had failed to make the train move forward, a few heads would have rolled for sure.

Taking into account that detecting and discarding duplicate records aren't the primary function of the system, but that it should be done whenever it's possible, we'd like to find a way to make job B, C, D, etc proceed even when job A (the job that maintain the Vsam file) hasn't ended OK.

Job B (C, D, etc) must run uninterruptedly even when the Vsam file doesn't exist. That’s why I'm looking for a way to deal with the "data set no found" ABEND.

What we're doing now is precisely what was suggested in one of the previous replies: we are creating the Vsam file if it doesn't exist at the moment of its use by job B.

It works fine, but it's not an elegant solution. Also, it makes possible for a lot of "experts" to say that we’re lousy workers with lousy solutions.

If I can’t dodge the “data set not found” abend, I would like to read the Vsam file dynamically but I don't know how. I know how to read Sam files dynamically, but don't know how to do the same with Vsam files.

Thanks.

dick scherrer · Posted: Mon Dec 21, 2009 3:41 am

Hello,

What about putting back thd previous contents if the current attempt to create fails?

Might this be better than not having the data at all?

If it is ok to run without the file and the previous content would not be good, what about defining the file and adding one dummy record so that processing would continue?

So far, i do not see a reason for the file to be "missing".

Possibly i've not understood something. . .

dick scherrer · Posted: Mon Dec 21, 2009 5:14 am

To add on. . .

Suggest that the primary focus be that this is a real production process and not focus on "Discarding duplicate records isn't the system main goal.". . .

IMHO, there is no good reason that this does not run correctly/completely every time.

fwiw,

d

karisurya · New User Joined: 02 Aug 2007 Posts: 64 Location: Bangalore

Hi,

Some time back we have a similar situation where the Dataset may/maynot exist and program should read onlf if the dataset is present and process.
We used the following syntax

enrico-sorichetti · Posted: Mon Dec 21, 2009 1:42 pm

Anuj Dhawan · Posted: Mon Dec 21, 2009 7:55 pm

vasanthz · Posted: Mon Dec 21, 2009 7:57 pm

Anuj Dhawan · Posted: Mon Dec 21, 2009 8:13 pm

Well, I just don't know what their process is doing - so won't be able to predict much and actually, would like to "quote" what Enrico has said.

in your (Vasanth) assumption you've assumed, entire process ends the moment program-in-question(P1) is executed or not. What if there are some "dowstream-programs" waiting for the output from P1...add one more IDCAMS step? and then one more...and few more...?