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From "Jonathan Ellis (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (CASSANDRA-5581) Use System.nanoTime() to measure intervals
Date Mon, 20 May 2013 22:09:16 GMT

     [ https://issues.apache.org/jira/browse/CASSANDRA-5581?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Jonathan Ellis updated CASSANDRA-5581:
--------------------------------------

    Attachment: 5581-v2.txt

Thanks!

LGTM except for the ReadCallback change.  The idea was that we may already have used up part
of our timeout (CASSANDRA-4705), so we want to compensate for that.  I've added a comment
and changed variable names to make that more clear in v2.
                
> Use System.nanoTime() to measure intervals
> ------------------------------------------
>
>                 Key: CASSANDRA-5581
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-5581
>             Project: Cassandra
>          Issue Type: Improvement
>            Reporter: Mikhail Mazursky
>            Assignee: Mikhail Mazursky
>            Priority: Minor
>             Fix For: 2.0
>
>         Attachments: 5581-v2.txt, trunk-5581.txt
>
>
> System.nanoTime() should always be prefered to System.currentTimeMillis() to measure
time intervals. It's not affected by system clock adjustments & drift.
> While testing C* we found that it's very unstable if system clock drifts. Problems happen
even under low load with tiny dataset. In our case other VMs on the same hardware box produced
high CPU load and system clock drifted a lot in C* VMs. We fixed that but there is definitelly
room for improvement in C* itself.

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