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https://issues.apache.org/jira/browse/CASSANDRA-6106?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13779603#comment-13779603
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Jonathan Ellis commented on CASSANDRA-6106:
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I dunno. If it's a problem, then don't paper over it ("less likely" is a
synonym for "still possible"); use LWT or fix your data model.
> 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().
> There seems to be some confusion here, so I'd like to clarify: the purpose of
> this patch is NOT to improve the precision of ordering guarantees for
> concurrent writes to cells. The purpose of this patch is to reduce the
> probability that concurrent writes to cells are deemed as having occurred at
> *the same time*, which is when Cassandra violates its atomicity guarantee.
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