On Fri, 26 Mar 2021, at 12:38, Joseph Reichman wrote:
> The output file is shared among multiple jobs whenever I get
> an equal condition I open put and close
That won't work if two jobs simultaneously try to write to the file.
You might not destroy the file, but you will lose the information that
the second job tried to write to it.
The jobs need
(a) not to allocate the output dataset at all in the JCL
(b) to have a retry loop that does something like the
following when you want to write data out
repeat
try to get exclusive use of the results file
if that fails and we've tried many times,
perhaps write the data somewhere else?
- though that might also fail
stop trying
end
if exclusive use isn't acquired but we've not tried
often, wait a bit (a random time interval) and
try again
if exclusive use was granted, update the file,
free it again, and stop trying
end
--
Jeremy Nicoll - my opinions are my own.
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