Delete and Create a dataset

vab987 · New User Joined: 01 Dec 2006 Posts: 29 Location: S.A

Hi,

Can someone please help me in understanding why the following JCL gives error whereas the second is perfect.

I'm deleting and then creating the same Dataset in these two jobs.

1)

expat · Posted: Fri Jan 16, 2009 7:00 pm

Because the dataset is allocated via the JCL until end of step, and the disposition of (MOD,DELETE,DELETE) will not be realised until end of step.

Therefor the dataset exists in that step, so you get JCL error for duplicate dataset

Mukesh Pandey · Active User Joined: 11 Nov 2008 Posts: 143 Location: India

STEP1
FILE1 DD DSN=x.y.z(1),
-----
-----
step4
FILE2 DD DSN=x.y.z(0), i.e(we are refereing the file created in step1..

if an abend occurs in step4 and need to restart the job from step4 then which version do we need to refer in step4 ?

interview question.....

superk · Posted: Fri Jan 16, 2009 8:25 pm

Mukesh Pandey · Active User Joined: 11 Nov 2008 Posts: 143 Location: India

my response was it would be (1) ........

Mukesh Pandey · Active User Joined: 11 Nov 2008 Posts: 143 Location: India

sorry.. my response was it would be (0) ....

superk · Posted: Fri Jan 16, 2009 8:38 pm

Is x.y.z supposed to represent a Generation Data Group (i.e. a GDG)? If so, then the (1) and (0) should represent relative generations, not versions. Your topic is confusing.

Mukesh Pandey · Active User Joined: 11 Nov 2008 Posts: 143 Location: India

yes it is a gdg generation...

superk · Posted: Fri Jan 16, 2009 9:33 pm

Mukesh, the scenario that I think you've described sounds rather odd to me, but here's my take:

In STEP1 of a job, you will create a new generation of a GDG dataset by specifying a relative generation number of +1 and by specifying (NEW,CATLG) for the disposition.

Let's say that before your job executes that are already 10 generations cataloged to the base. The most current generation (the '0' generation) at this moment is X.Y.Z.G0010V00.

Before the job starts to execute, JES will resolve any of the relative generation references to their actual real value. Let's say that in STEP1, your relative generation of +1 is now resolved to be X.Y.Z.G0011V00. That means that, in the same job, if in STEP4 you want to use the same generation dataset that you referred to in STEP1, then you must also refer to it using the +1 relative generation.

Now, if STEP1 executes correctly and catalogs the new generation G0011V00, but then the job abends, then G0011V00 will now be the current generation (generation '0'), and if you wish to restart the job at STEP4, then the relative generation will have to be changed from +1 to 0.

Douglas Wilder · Posted: Fri Jan 16, 2009 9:48 pm

1) What does this have to do with the original question from vab987?
2) x.y.z(0) in step4 would not refer to the generation created in step1 of the same job! It would refer to the latest generation before the job started. To refer to that same generation when restarting the job in step4 after step1 has cataloged a new generation you would need to change the generation in step4 to (-1).

expat · Posted: Sat Jan 17, 2009 2:43 am

gcicchet · Posted: Sat Jan 17, 2009 5:35 am

Hi,

this thread is getting confusing, there seems to be 2 unrelated questions by different people.

I believe Expat answered the first question.

Regarding the second question, I'm with Kevin, if a GDG is created correctly in STEP1 with a (+1) and STEP4 of the same job needs to reference it, it also needs to use (+1).

If STEP4 needs to be restarted because of some abend, the JCL will need the (+1) to be changed to 0 or +0.

This is making assumptions that no other steps between STEP1 and STEP4 created +2 and +3 etc GDGs.

Gerry

Terry Heinze · Posted: Sat Jan 17, 2009 6:48 am

Confusing to say the least.
Mukesh,
Please start a new thread for a different question.
Vab,
DDNAMEs should be unique for a job step. See JCL manual.

vab987 · New User Joined: 01 Dec 2006 Posts: 29 Location: S.A

Thanks for all those replied.

Regards,
Vaibhav

Mukesh Pandey · Active User Joined: 11 Nov 2008 Posts: 143 Location: India

Superk and Douglas.. thanks for the response.. it is clear now.....

abhishek dadhichi · New User Joined: 19 Apr 2007 Posts: 37 Location: Bangalore

Hi Douglas,

I just thought of this...Suppose if the the generation which is created in the Step01 is the only generation for that GDG base i.e it is the latest one
,then I think we need to mention (+0) in Step04 after it is restarted as that is the latest and the only one..

Plz correct me if I am wrong!!

Thanks,
Abhishek

gcicchet · Posted: Mon Jan 19, 2009 11:07 am

Hi,

I think you should read all of the replies, maybe I didn't make it clear but that's exactly what Kevin and I mentioned.

If you restart STEP04, you need +0 to refernce the dataset created in STEP01.

Gerry