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Magesh_J Intermediate
Joined: 21 Jun 2014 Posts: 259 Topics: 54
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Posted: Thu Sep 21, 2017 6:05 pm Post subject: Set ACB parameter for a VSAM file |
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Hi,
Please advise, how do i change/set ACB parameter for vsam dataset in batch.
Example :
Code: | //VSAM1 DD DSN=VSAMDATA,DISP=SHR,AMP=('ACCBIAS=SW') |
For above vsam dataset, i need to set MACRF=(NSR,SEQ,DIR,OUT,SKP)
How do i set it or where do i set this option.
Thanks
Magesh |
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kolusu Site Admin
Joined: 26 Nov 2002 Posts: 12375 Topics: 75 Location: San Jose
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Posted: Fri Sep 22, 2017 11:13 am Post subject: |
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Magesh_J,
With ACCBIAS=SW you are already getting SEQ,SKP
If you want both Direct access and sequential access of records change it to ACCBIAS=DW
Look up Table 14. SMB access bias guidelines in z/OS DFSMS Using Data Sets Here
http://publibz.boulder.ibm.com/epubs/pdf/dgt3d410.pdf
Read Chapter 10. Optimizing VSAM Performance _________________ Kolusu
www.linkedin.com/in/kolusu |
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Magesh_J Intermediate
Joined: 21 Jun 2014 Posts: 259 Topics: 54
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Posted: Fri Sep 22, 2017 1:05 pm Post subject: |
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Thanks Kolusu for the kind response.
All i need is make my program/jcl use NSR buffer instead of LSR
When we specify AMP=('ACCBIAS=DW') It switches to LSR resulting in performance problem.
When i specify AMP=('BUFND=39,BUFNI=139') , It is running very good.
But the problem is BUFNI will always varies based on the calculation
Code: |
BUFNI = TI - (HURBA / CASIZE) + STRNO
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All I need is AMP=('ACCBIAS=DW') and NSR Buffer.
I see following program in the book, but not sure how to write or where to write and how to invoke for my vsam file.
Code: |
START CSECT
SAVE(14,12) Standard entry code
.
B INIT Branch around file specs
MASACB ACB DDNAME=MASDS,AM=VSAM, File specs X
MACRF=(KEY,SEQ,OUT), X
EXLST=EXITS, X
RMODE31=ALL
END
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Thanks
Magesh |
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kolusu Site Admin
Joined: 26 Nov 2002 Posts: 12375 Topics: 75 Location: San Jose
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Posted: Fri Sep 22, 2017 11:28 pm Post subject: |
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Magesh_J,
You need to have a dataclass that supports SMB. Talk to your systems programmer and have the VSAM dataset in a dataclass with SMB _________________ Kolusu
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Magesh_J Intermediate
Joined: 21 Jun 2014 Posts: 259 Topics: 54
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Posted: Tue Sep 26, 2017 6:27 pm Post subject: |
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Thanks Kolusu, Will check with System programmer.
Regards,
Magesh |
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