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Regarding the RECORDSIZE( AVG, MAX) OF A VSAM FILE ???


IBM Mainframe Forums -> JCL & VSAM
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sidharthmadaan1984

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Joined: 06 Apr 2008
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PostPosted: Thu Apr 17, 2008 1:12 pm
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I'm using a VSAM file while previously had a RECORDSIZE(237, 306) and the minimum and the maximum record length used was 160 and 306 respectively...

Now, in the same VSAM file the maximum record length has been updated to 466 but the minimum record length is same as 160, so my question is that whether we need to update the RECORDSIZE parameter's average record length also ??? If yes, then what should it be changed to ??? How essential it is, i mean will that make an impact on the file if we dont change it ???

Regards,

Sidharth.
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expat

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PostPosted: Thu Apr 17, 2008 2:00 pm
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Keeping the average the same should not have any impact.
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sidharthmadaan1984

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PostPosted: Thu Apr 17, 2008 2:17 pm
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hi,

thanx for your reply dear...

just wanted to know if we want to change it then what should it be ???


Regards,
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CICS Guy

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Joined: 18 Jul 2007
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PostPosted: Thu Apr 17, 2008 5:37 pm
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sidharthmadaan1984 wrote:
just wanted to know if we want to change it then what should it be ???
If the average length significantly changes, feel free to update it, VSAM uses it for efficiency...
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Eugene S Hudders

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PostPosted: Fri Apr 18, 2008 9:37 pm
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Hi:

The average record size is only used when you define the disk space requirements using the RECORDS option. In most cases, users do not know the average record length, so the results can be reflected in multiple extents when the file is initially loaded (e.g., you used the minimum instead of the average) to excessive over-allocation when you overstated the average. The figure you provide is kept in the catalog and never updated by VSAM. If you are allocating disk space using CYLINDERS or TRACKS, then the average record length will not have any effect on your definition.

Regards,
Gene
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