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https://issues.apache.org/jira/browse/CASSANDRA-2976?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13073146#comment-13073146
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Zhu Han commented on CASSANDRA-2976:
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For file system with coarse time resolution, e.g. ext3 with 1s resolution, this
problem can be reproduced much easily...
> Severe bug on commit log replay
> -------------------------------
>
> Key: CASSANDRA-2976
> URL: https://issues.apache.org/jira/browse/CASSANDRA-2976
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Affects Versions: 0.6.13
> Reporter: Zhu Han
> Original Estimate: 4h
> Remaining Estimate: 4h
>
> For 0.6, the replay order of commit log is determined by modify time(mtime)
> of commit log files. The roll and update of a new log segment can be finished
> under 1ms if the log device is backed up by BBU or it is a SSD with super
> capacitor. So the last log segment and previous segment can have the same
> mtime.
> While File#listFiles() does not guarantee the order of return files, after
> sorting by mtime, it is possible that the new log segment are replayed before
> old log segment. This can causes data loss!
> Here is the output of log, you can observe from the timestamp in the commit
> log file names that new log segment are replayed before old segment...
> INFO [main] 2011-07-30 01:21:07,569 CommitLog.java (line 171) Replaying
> /var/lib/cassandra/commitlog/CommitLog-1311959800795.log,
> /var/lib/cassandra/commitlog/CommitLog-1310661748573.log,
> /var/lib/cassandra/commitlog/CommitLog-1311838097776.log
> INFO [main] 2011-07-30 01:21:07,571 CommitLog.java (line 286) Finished
> reading /var/lib/cassandra/commitlog/CommitLog-1311959800795.log
> INFO [main] 2011-07-30 01:21:15,813 CommitLog.java (line 286) Finished
> reading /var/lib/cassandra/commitlog/CommitLog-1310661748573.log
> INFO [main] 2011-07-30 01:21:15,865 CommitLog.java (line 286) Finished
> reading /var/lib/cassandra/commitlog/CommitLog-1311838097776.log
> INFO [main] 2011-07-30 01:21:15,926 CommitLog.java (line 174) Log replay
> complete
> I have not checked 0.7.x and 0.8.x, I suppose they both have the same problem.
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