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From "Jonathan Ellis (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-6106) Provide timestamp with true microsecond resolution
Date Thu, 24 Apr 2014 15:34:18 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-6106?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13979841#comment-13979841
] 

Jonathan Ellis commented on CASSANDRA-6106:
-------------------------------------------

Do you have time to look at the math, [~xcbsmith]?  The code itself is a single class and
reasonably straightforward.

> Provide timestamp with true microsecond resolution
> --------------------------------------------------
>
>                 Key: CASSANDRA-6106
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-6106
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>         Environment: DSE Cassandra 3.1, but also HEAD
>            Reporter: Christopher Smith
>            Assignee: Benedict
>            Priority: Minor
>              Labels: timestamps
>             Fix For: 2.1 beta2
>
>         Attachments: microtimstamp.patch, microtimstamp_random.patch, microtimstamp_random_rev2.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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