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erlang:now issues when generating ids #4

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ghost opened this issue Mar 26, 2012 · 0 comments

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ghost commented Mar 26, 2012

Problem stems from the fact that "guaranteed that subsequent calls to this BIF returns continuously increasing values"; see also https://github.com/erlang/otp/blob/master/erts/emulator/beam/erl_time_sup.c#L849
Hence

"Sequence counter" id field will never go higher than 1000, wasting precious 6 bits.
Generating more than 10e6 ids per second in one erlang wm will cause skewness of "time" id field, possibly resulting in incorrect ordering of ids from different machines; incomparability margin of these ids could grow uncontrollably.

Solution
Simply replacing erlang:now with os:timestamp seems to be enough.

ghost assigned d2fn

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