Marco,
Have all the phantoms use a function or subroutine to get the next id
based on the current system milliseconds. Use a semaphore lock to keep
it singleton. Add a "NAP" statement so the next time it's run you're
sure to get a different millisecond count -- note that many systems
won't give 1ms granularity (IIRC Windows is about 6ms):
FUNCTION GET.NEXT.ID
*
EQU MY$SEMAPHORE TO 55
EQU TD$TICKS LIT '(SYSTEM(99):((SYSTEM(12) * 1000) "R%3"))'
*
LOCK MY$SEMAPHORE
MY.ID = TD$TICKS
NAP 15 ;* must be big enough to get unique id's
UNLOCK MY$SEMAPHORE
RETURN (MY.ID)
END
rex
Marco Manyevere wrote:
What is the most reliable way to generate unique sequential keys without
having to resort to a record on disk updated through readu/write? The keys
don't have to be contiguous but only be sortable in the order in which they
were generated by several phantom processes running concurrently. I'm
currently approximating this using a concatenation of date and time with
millisecondsB but I'm worried about the possibility of two phantoms generating
exactly the same key.
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