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https://issues.apache.org/jira/browse/ZOOKEEPER-1366?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14302605#comment-14302605
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Patrick Hunt commented on ZOOKEEPER-1366:
-----------------------------------------
It should be ok to have calls to currentTimeMillis - if the call is associated
with wall clock time (like the time/datestamp of a znode creation). nanoTime
should be used whenever these is "elapsed time" to consider. E.g. session
expiration.
Would be great to see someone pick this up - would be a great addition to 3.5.
> Zookeeper should be tolerant of clock adjustments
> -------------------------------------------------
>
> Key: ZOOKEEPER-1366
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-1366
> Project: ZooKeeper
> Issue Type: Bug
> Reporter: Ted Dunning
> Assignee: Ted Dunning
> Priority: Critical
> Fix For: 3.5.1
>
> Attachments: ZOOKEEPER-1366-3.3.3.patch, ZOOKEEPER-1366.patch,
> ZOOKEEPER-1366.patch, ZOOKEEPER-1366.patch, ZOOKEEPER-1366.patch,
> ZOOKEEPER-1366.patch, ZOOKEEPER-1366.patch, ZOOKEEPER-1366.patch,
> ZOOKEEPER-1366.patch, ZOOKEEPER-1366.patch, ZOOKEEPER-1366.patch,
> zookeeper-3.4.5-ZK1366-SC01.patch
>
>
> If you want to wreak havoc on a ZK based system just do [date -s "+1hour"]
> and watch the mayhem as all sessions expire at once.
> This shouldn't happen. Zookeeper could easily know handle elapsed times as
> elapsed times rather than as differences between absolute times. The
> absolute times are subject to adjustment when the clock is set while a timer
> is not subject to this problem. In Java, System.currentTimeMillis() gives
> you absolute time while System.nanoTime() gives you time based on a timer
> from an arbitrary epoch.
> I have done this and have been running tests now for some tens of minutes
> with no failures. I will set up a test machine to redo the build again on
> Ubuntu and post a patch here for discussion.
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