On 12/07/2018 10:46 AM, Paul Gilmartin wrote:
Is it any worse than if the processes operated sequentially; no overlap.
Second guy wins. Conscientious second guy will create the file with
O_EXCL. If you don't trust the second guy, lock him out with RACF profile
or file permissions.
It probably is worse, e.g. a likely example is where the second guy is
processing the output from the first guy. The designers of z/OS thought
this scenario was most likely an error and so protected you from it - I
tend to agree.
I don't trust the second guy to get the serialization right, where it is
not built-in.
If I want to be very nondisruptive I write to a temp name and rename at
the end. This guarantees that no other job sees the update in transit.
Creating temporary files has its own security exposures. I am always
wary in case I am creating a security problem I don't understand.
--
Andrew Rowley
Black Hill Software
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