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Multiple access of VSAM in batch

 
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Amit Goswami

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Joined: 06 Jul 2005
Posts: 11
Location: India

PostPosted: Wed Oct 08, 2008 9:19 am    Post subject: Multiple access of VSAM in batch
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Hi,

I have one program that opens a VSAM file in input mode and read it randomly. The record key for file is the records of another file that may vary from 1 to 1m.

There are many job that execute this program simultaneously and hence may perform read on VSAM file using keys from their individual file.

Does this affect the processing of job? I mean contention on file opening.

My another question is, since my program is a middle program so I am opening file only once but after reading the records or at the end of processing I am not closing it. Would it affect anything?
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dick scherrer

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Joined: 23 Nov 2006
Posts: 19270
Location: Inside the Matrix

PostPosted: Wed Oct 08, 2008 9:25 am    Post subject:
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Hello,

Quote:
Does this affect the processing of job? I mean contention on file opening.
It could. . . All of the reads will cause contention also.

Quote:
after reading the records or at the end of processing I am not closing it. Would it affect anything?
Probably not. I suspect that when the process is finished reading the control file, it ends which wo8uld automatically close the vsam file.

You might want to consider limiting how many of this process might run concurrently if performance is an issue.
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