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Christopher Smith commented on CASSANDRA-6106:
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I should clarify my comment about client assigned time stamps.
If you don't mask off bytes in the client generated timestamps for storing the
node ID, then they aren't comparable with server generated timestamps, which
will cause problems.
The best you could do is store one extra bit to indicate whether it was a
client or server generated timestamp and somehow resolve cases of mixed client
& server values accordingly. However, I think that's a huge can of worms not
worth diving into. It's better to just use all of the existing 64-bits to store
the timestamp and store any and all additional information in additional bytes.
> QueryState.getTimestamp() & FBUtilities.timestampMicros() reads current
> timestamp with System.currentTimeMillis() * 1000 instead of System.nanoTime()
> / 1000
> ------------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-6106
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6106
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Environment: DSE Cassandra 3.1, but also HEAD
> Reporter: Christopher Smith
> Priority: Minor
> Labels: collision, conflict, timestamp
> Attachments: microtimstamp.patch
>
>
> I noticed this blog post: http://aphyr.com/posts/294-call-me-maybe-cassandra
> mentioned issues with millisecond rounding in timestamps and was able to
> reproduce the issue. If I specify a timestamp in a mutating query, I get
> microsecond precision, but if I don't, I get timestamps rounded to the
> nearest millisecond, at least for my first query on a given connection, which
> substantially increases the possibilities of collision.
> I believe I found the offending code, though I am by no means sure this is
> comprehensive. I think we probably need a fairly comprehensive replacement of
> all uses of System.currentTimeMillis() with System.nanoTime().
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