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Dear Experts ,

In the existing system--- Repro is done on a Vsam file into a PS and PS is input to program.
Proposed Future state --- suggests to use VSAM KSDS directly as input to program for sequential access.

We have astronomical volume of data (bank), and there are 3 such files as input to the program.

I would want to know which of the above two performs better

Would syncsort for copy and then PS as input give better performance than both of the above.

Please suggest.

Repro is known to be slower than sort.

have you insured that you had large blocksize output
have you increased the DD BUFFNO parm for the program reading the PS.

you can increase ksds reads by amp parm

the idea is to reduce hardware I/O.

so you have to find a balance where copying/processing is faster that reading the ksds directly, since the ksds is somewhat delimited by ci/ca size.

would suggest you refer to VSAM Demystified Redbook

you have to experiment and test.

on a more rational note:

you have to be doing something really wrong
if a repro and process ps is faster than just reading the ksds.