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Cogito-Ergo-Sum · Posted: Thu Nov 09, 2006 7:48 am Post subject: FSPC(0 0) for a VSAM KSDS

Hi,
I am aware of the meaning of FREESPACE(0 0). I am also clear about a CI/CA splits. But, I am not sure, I fully understand by the meaning of 0% for the CI and CA. With the CI% set to 0, it means, that the whole of CISZ is meant to be used by records. That means, the probability of a CI split is higher here. If FSPC was coded as non-zero, then the next available CI would be used.

Can someone please explain why would anyone choose FSPC(0 0) for a VSAM KSDS ?
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ALL opinions are welcome.

Debugging tip:
When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.
-- Sherlock Holmes.

warp5 · Posted: Fri Nov 10, 2006 2:42 am Post subject:

Probably just for documentation purpose, this is the default anyway. Maybe there was a value in there before and now 0 is used. Maybe updates are not being done anymore - just a read dataset. In any case, it is often better to have a 0 FSPC for CI and use a FSPC for the CA instead.

Cogito-Ergo-Sum · Posted: Fri Nov 10, 2006 4:41 am Post subject:

warp5 · Posted: Mon Nov 13, 2006 2:36 am Post subject:

Why don't you post the definitions and information so we can give an opinion on them.

Bill Dennis · Posted: Mon Nov 13, 2006 9:18 am Post subject:

Or perhaps the updates are mostly additions to the end of the keyrange?
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Bill Dennis

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warp5 · Posted: Tue Nov 14, 2006 2:16 am Post subject:

Or the updates maybe so scattered that freespace does not really help, or maybe they should be mass inserted, or .......
More information and details are needed.

Cogito-Ergo-Sum · Posted: Wed Nov 15, 2006 8:50 pm Post subject:

warp5,
The inserts are generally towards the end of keyrange; as mentioned by Bill D. It is rarely scatterred out.

After spending some more time on the program, I have a feeling that, the program can be replaced with a delete/define/load steps in the job.

I know, I am providing scanty information; but, that is more because I am not really sure what information is sought after. Given that, the file is used in batch only (and, used by CICS when batch is down) and is heavily updated towards the end of keyranges, what is the next step in deciding FSPC values for CA ?
_________________
ALL opinions are welcome.

Debugging tip:
When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.
-- Sherlock Holmes.

warp5 · Posted: Thu Nov 16, 2006 2:23 am Post subject:

It sounds to me as if you would be better off not to have any FSPC at all, as the cluster is now defined. Using freespace would just waste space because the inserts would only affect the last few CAs of the cluster (inserts are at the end of the keyrange). Mass insert might be usefull if it is possible.