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GDG all in sequence order


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steve-myers

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PostPosted: Fri Dec 24, 2021 10:31 pm
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In JCL,

// DD DISP=SHR,DSN=gdgbase

will allocate data sets in order newest, next,..., oldest

I believe it is possible to have it allocate oldest,... newest order, but I couldn't quickly find out how to do it.

Help!
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enrico-sorichetti

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PostPosted: Sat Dec 25, 2021 1:42 am
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it should be something along the lines of

Code:
...
//ddname DD DSN=<the gdg.base.name>,DISP=SHR,GDGORDER=FIFO
...
//ddname DD DSN=<the gdg.base.name>,DISP=SHR,GDGORDER=LIFO
...


the silly google search I used

Quote:
allocating a gdg in reverse order

and the first hit was the link to the manual
www.ibm.com/docs/en/zos/2.3.0?topic=set-retrieving-all-generation-data-sets
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enrico-sorichetti

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PostPosted: Sat Dec 25, 2021 1:43 am
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hit the mouse button a couple times more than needed
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steve-myers

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PostPosted: Sat Dec 25, 2021 8:56 pm
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Thank you Enrico.

I think I looked everywhere in the JCL Reference manual except the DD statement section. For some reason I thought it was a JOB statement parameter. Actually, now that I think about it, GDGORDER on the DD statement makes a lot more sense than a JOB statement parameter where you already have that GDGBIAS parameter to confuse thing even more.

I have to admit I'm really bad about silly Google search parameters.

Merry Christmas.
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Joerg.Findeisen

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PostPosted: Sun Dec 26, 2021 2:55 pm
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@Steve: If you want to have it permanently w/o altering the JCL, please see IDCAMS ALTER <gdg_base> LIFO|FIFO command.
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steve-myers

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PostPosted: Sun Dec 26, 2021 9:28 pm
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Yes, I noticed that in the IDCAMS manual. It raises the question what happens when you combine them: FIFO defined for the index, and GDGORDER=LIFO. What happens when you ALTER FIFO a populated index created LIFO? I should go back to the IDCAMS manual and see if it says anything. I've mostly been working on other things; mostly interpreting IGGCSI00 output. The GDGORDER came up when I built a GDG index to investigate CSI00 output and then I thought about reordering.
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Rohit Umarjikar

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PostPosted: Mon Dec 27, 2021 9:48 am
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I don’t remember but cbttapes have something for this , try GDGCOPY. When I searched it’s file482 not sure if that would do the trick.
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Joerg.Findeisen

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PostPosted: Mon Dec 27, 2021 3:57 pm
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steve-myers wrote:
Yes, I noticed that in the IDCAMS manual. It raises the question what happens when you combine them: FIFO defined for the index, and GDGORDER=LIFO. What happens when you ALTER FIFO a populated index created LIFO? I should go back to the IDCAMS manual and see if it says anything. I've mostly been working on other things; mostly interpreting IGGCSI00 output. The GDGORDER came up when I built a GDG index to investigate CSI00 output and then I thought about reordering.

From my experience, the JCL GDGORDER always overrides the Catalog. FIFO basically makes the most sense with SMF-Data and alikes.
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don.leahy

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Joined: 06 Jul 2010
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PostPosted: Thu Dec 30, 2021 5:06 am
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Joerg.Findeisen wrote:
steve-myers wrote:
Yes, I noticed that in the IDCAMS manual. It raises the question what happens when you combine them: FIFO defined for the index, and GDGORDER=LIFO. What happens when you ALTER FIFO a populated index created LIFO? I should go back to the IDCAMS manual and see if it says anything. I've mostly been working on other things; mostly interpreting IGGCSI00 output. The GDGORDER came up when I built a GDG index to investigate CSI00 output and then I thought about reordering.

From my experience, the JCL GDGORDER always overrides the Catalog. FIFO basically makes the most sense with SMF-Data and alikes.
I prefer the JCL GDGORDER as it makes it clear that the traditional default is not being used.
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Joerg.Findeisen

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PostPosted: Thu Dec 30, 2021 11:44 am
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don.leahy wrote:
I prefer the JCL GDGORDER as it makes it clear that the traditional default is not being used.

For SMF-Data our shop has altered all GDG Base entries. That was quicker than mass updates of JCLs on every LPAR. But yes, I see your point for "not so obvious" entries. icon_cool.gif
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