Space problem in JCL

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sandeep saini
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Joined: Fri Sep 21, 2007 11:36 am

Space problem in JCL

Post by sandeep saini » Thu Oct 04, 2007 4:43 pm


Actually my problem is that in my job the input dataset is having varying number of records.Sometimes it comes to 100,sometimes 10000,means its varying.But the problem is when I am specifying the space parameters it will abend as I am not sure about the number of records.
So,Is there any way to optimize this like depending upon the number of records it will allocate space(apart from RLSE parameter).

Thanks and Regards

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Post by Veera » Fri Oct 05, 2007 12:56 am

Hi Sandeep,

I dont think so there is a way by which the system calcualtes the space
by itself based on the no of recs in the I/P file.

Well, you have any issue with the RLSE parameter anyhow the memory
gets released matter how much you specify.

Otherwise you can go for Tapes...if you have an option ...

Lets see if some one responds and if there is a dynamic way of calculating the space as you have asked would be good to know.


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Post by DavidatK » Sat Oct 06, 2007 2:17 am


Will you know the number of records prior to allocation? There may be some overrides if you do know.

But allocating sufficient, but not to much space if the function of the 'RLSE' keyword. Allocate for the max and then release unused space upon closing.

You can also try to allocate space using extents.

SPACE=(recsz,(prim alloc, second alloc),RLSE),AVGREC=U

recsz = your LRECL
prim alloc = average number of records
second alloc = 1/14 (max number of records ? average number of records)

lets say the average number of records you will be allocating for is 2500 and the max number of records that you will allocate is 100,000.

Then the allocation might look like


Where prim alloc is for space for 2500 records of LRECL=200
And the secondary alloc will be for up to 14 allocations of space for 6965 records for LRECL=200

2500 + (6965 * 14) = 100,010 records

sandeep saini
Posts: 2
Joined: Fri Sep 21, 2007 11:36 am

Post by sandeep saini » Tue Oct 09, 2007 10:26 am


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