[email protected] (Mark Jacobs) wrote:
There "might" be some slight performance impact, and also check for any
missing maintenance. That being said, we've had it turned on since zOS
1.12 and it's never caused a problem.
<snip>
I am not a VSAM expert, and I didn't stay in a hotel of any description
last night, but...
- For the overwhelming majority of things I'm told we expect CA reclaim
to improve performance (and keep a lid on space utilization too),
sometimes significantly.
- There is a rather pathological case for which you should not enable CA
reclaim, which as far as I know we have only ever seen for real within
IBM. If you insert enough records into a specific keyrange to split a CA
(maybe more than once), and then delete them all, and then add records
back into that same keyrange, rinse, and then repeat a few times, the
overhead of repetitive CA reclaim/split processing won't exactly help
performance. If it develops that you actually do have a data set that's
processed that way, turn it off for that data set.
--
John Eells
z/OS Technical Marketing
IBM Poughkeepsie
[email protected]
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