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kranti

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Joined: 10 Oct 2005
Posts: 27

PostPosted: Thu Oct 22, 2009 12:41 pm    Post subject: Job performance
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Hi,

We have in our application something like Backup and reload of Vsam files.

Backup process reads all VSAM files and writes into two flat files, both the files are almost being written with the same data. As the files are needed to hold large data, these were defined with compression option.

During reload process, the records in flat files would be written back to Vsam files.

Observation we made that the backup process runs for 2 hours where as reload completes in 15 minutes.

Is it because the flat files are defined with compression option?

we also noticed that the cobol program for backup was compiled with TEST SYM option which made load to be big.
Is this the culprit for running backup for longer time?

Please advice.
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expat

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Joined: 14 Mar 2007
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Location: Back in jolly old England

PostPosted: Thu Oct 22, 2009 12:57 pm    Post subject:
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Have you tried using IDCAMS, either REPRO/REPRO or EXPORT/IMPORT to do this task.

Also if your site has FAVER installed, use this, as it is an excellent VSAM backup/restore product.
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kranti

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PostPosted: Thu Oct 22, 2009 1:08 pm    Post subject: Reply to: Job performance
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Hi Expat,

Unfortunately we can not use the IDCAMS or any utility for backup/reload as it should be program driven.

Duing the backup/reload proces we drop older data and write back remaining into the vsam files.

Coming to my question, would any of the reasons mentioned in my last tag causing the job to run for longer time?

Thanks.
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Robert Sample

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Location: East Dubuque, Illinois, USA

PostPosted: Thu Oct 22, 2009 4:38 pm    Post subject:
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The job could run longer due to program logic, conflicts with other jobs running at the same time that are done by the time the reload starts, or even other reasons.

Since you are testing data in each record, it is pretty much a given that the unload (back up) time will be longer than the reload time where you are not doing anything but putting records into the file.

Your best bet would be to contact your site support group and have them help you analyze the reason(s) for the time difference.
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dbzTHEdinosauer

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Location: porcelain throne

PostPosted: Thu Oct 22, 2009 6:38 pm    Post subject:
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using idcams parameters properly, there is a good chance that you can do away with the cobol program if you are only making a date check.
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dick scherrer

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Joined: 23 Nov 2006
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PostPosted: Thu Oct 22, 2009 9:19 pm    Post subject:
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Hello,

You might also look into using your sort product - it will probably run faster than idcams and most likely faster than the cobol code. . .
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