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Pandora-Box
Global Moderator
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Joined: 07 Sep 2006
Posts: 1592
Location: Andromeda Galaxy
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Hi all,
Is there any other best way to access VSAM file from CICS ( Which just does a read ) and Batch process ( Updates the vsam file ) simultaneously apart from using RLS option which is not being an option in my shop??
Also this should be achieved without bothering CICS program execution.
Any suggestions or pointers will be really helpful indeed
Thanks |
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Robert Sample
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Joined: 06 Jun 2008
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Location: Dubuque, Iowa, USA
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Are you expecting that the CICS region will be able to retrieve the updates made by the batch program?
There is a defined interface to allow batch programs access to CICS files (actually, there's even more than one such interface). You would do best by reading up on them. |
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Pandora-Box
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Joined: 07 Sep 2006
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Location: Andromeda Galaxy
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| Are you expecting that the CICS region will be able to retrieve the updates made by the batch program? |
Doesnt RLS option in FCT support this??
I understand RLS is something like SHR (in JCL) which allows others to use the file so probably when it gets overwritten is it not possible to read updated data ?? Please correct my understanding 
Since my shop doesnt support I coudnt try that out
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| There is a defined interface to allow batch programs access to CICS files (actually, there's even more than one such interface). You would do best by reading up on them. |
I am sorry I really dont know the name of the interface so only then I can read about them  |
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Peter cobolskolan
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Joined: 06 Feb 2012
Posts: 104
Location: Sweden
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| EXCI, EXternal Cics Interface, not to be mixed up with ECI, External Call Interface. |
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Pandora-Box
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Joined: 07 Sep 2006
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| Thanks Peter would try it and get back. |
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Robert Sample
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Joined: 06 Jun 2008
Posts: 8700
Location: Dubuque, Iowa, USA
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Make up your mind what you want. This
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| apart from using RLS option which is not being an option in my shop?? |
directly contradicts
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| Doesnt RLS option in FCT support this?? |
If your site doesn't allow RLS, why do you keep bringing it up? If you're not using RLS, you need to be familiar with how CICS handles data going to and from a file -- for example, there's been more than one post on this forum where someone expected data written by CICS to be immediately available to a batch program and unless the application takes steps to ensure that CICS is flushing the buffers, the data won't necessarily be seen by batch programs for possibly many hours.
The CICS External Interfaces Guide manual is a good place to start reading on the EXCI interface. |
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dick scherrer
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Joined: 23 Nov 2006
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Hi Robert,
I believe in this case, the CICS access will be only reads. If i understand the question (and i well may not), will the batch updates be visable to online reads?
Hope i've not provided any confusion/mis-direction.
The good news is that if i have, i can remove it 
d |
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Pandora-Box
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Hi Dick,
You got it right!! |
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dbzTHEdinosauer
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Joined: 20 Oct 2006
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Location: porcelain throne
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what you are asking for is a batch update to cause cics to refresh its buffers
(in the case the updated record is in a ci currently in a buffer)
i don't feel like spending the time to research in order to justify or refute the above.
i can only guess, so i will not. |
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Bill O'Boyle
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Robert Sample
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Joined: 06 Jun 2008
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Location: Dubuque, Iowa, USA
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That will depend upon whether or not the VSAM file is in an LSR pool. From the CICS Performance Guide in the VSAM Tuning section:
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| Before issuing a read to disk when using LSR, VSAM first scans the buffers to check if the control interval it requires is already in storage. If so, it may not have to issue the read. This buffer "lookaside" can reduce I/O significantly. |
So if you're using LSR, the batch update wouldn't necessarily be seen by CICS, although the manual is not clear about precisely what circumstances would cause a buffer read versus disk access. Either don't use LSR for the file (which may, in turn, cause other performance issues) or do some testing before implementing the situation you're talking about to see how it works in reality. |
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Pandora-Box
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Looks like lot of reading need to be done ahead
Thanks all |
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vasanthz
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Joined: 28 Aug 2007
Posts: 1744
Location: Tirupur, India
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Hello,
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| Is there any other best way to access VSAM file from CICS ( Which just does a read ) and Batch process ( Updates the vsam file ) simultaneously apart from using RLS |
I think DFSMStvs - (transactional vsam services) allows VSAM sharing between CICS and Batch.
DFSMS Transactional VSAM Services (DFSMStvs) is an optional z/OS feature that enables batch jobs and CICS online transactions to update shared VSAM data sets concurrently. Multiple batch jobs and online transactions can be run against the same VSAM data sets, and DFSMStvs helps ensure data integrity for concurrent batch updates while CICS ensures it for online updates.
I have no personal experience in using it, just theoritical idea of how it works with coupling facility processors. |
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Pandora-Box
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Joined: 07 Sep 2006
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Location: Andromeda Galaxy
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Thanks all for your inputs & time very valuable indeed.
Also the design is changed to make sure the file is closed and opened again in FCT after VSAM file is updated |
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Jose Mateo
Active User
Joined: 29 Oct 2010
Posts: 121
Location: Puerto Rico
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Good day to all!
Read up on VSAM share options. Specifing the correct share option you could do what you are asking for. |
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