Yes, you can have a CA split without a CI split. You add a record
that needs to go into a new cylinder because there is no room in
the current one.
Take, for instance, a file that has records added to it using the
date and time for the key. Now you add 20 records, so we will say
that 5 records will fill a cylinder for our argument. Assuming it
hasn't changed, each cylinder is a CA. So you fill up a CA and
then have to go to a new one. There are no CI splits in doing
this with the proviso that the records are added in sequentially
increasing order.
CI splits happen when you need to insert in the "middle" of a CA
and it causes the split and this requires there to be free space
when that happens (if free space is specified which can be
"ALTERed" in after initially loaded).
HTHs
Steve Thompson
On 3/14/2024 5:49 PM, Pommier, Rex wrote:
Hello list,
I have a couple questions about VSAM KSDS and splits. For example, if I create
a KSDS with FSPC(0 0) and load it, there is no free space in it. I then come
along and try to insert a record somewhere in the middle of a CI. This will
result in a CI split which will then result in a CA split. Does this sequence
result in both a CI and CA split in the VSAM statistics? Assuming that this
scenario results in an increment in both the CI and CA split counts, is there
any way a VSAM dataset can incur a CA split without a corresponding CI split?
I am looking at a test VSAM that was built with minimal free space (3 0) and
then it had a batch job run against it, doing inserts, deletes and a minor
amount of updates. Once the job ended I looked at the statistics and found
this:
SPLITS-CI----------50319
SPLITS-CA----------50555
Variable length records, average length 380, max length 4500. CISZ 18432. Non
spanned records.
How can I have 200 more CA splits than CI splits?
Thanks,
Rex
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