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From "Jiaqi Tan (JIRA)" <j...@apache.org>
Subject [jira] Commented: (CHUKWA-305) Inconsistent time inputs
Date Wed, 17 Jun 2009 18:52:07 GMT

    [ https://issues.apache.org/jira/browse/CHUKWA-305?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12720827#action_12720827
] 

Jiaqi Tan commented on CHUKWA-305:
----------------------------------

It's not obvious if this is a Chukwa bug or a Hadoop issue, but if Hadoop is emitting logs
that do not have timezones, then there's nothing Chukwa can do about it.

To be more specific, I ran into this problem when I generated data using a cluster in EDT,
and then processed the data on a system in PDT. The times in the Job History logs are correct
since they are stored in UTC, but the log-processing on the machine in PDT reads the EDT time
strings and assumes they are in PDT, resulting in the data from the text-based log sources
being 3 hours ahead of the data in the Job History logs.

> Inconsistent time inputs
> ------------------------
>
>                 Key: CHUKWA-305
>                 URL: https://issues.apache.org/jira/browse/CHUKWA-305
>             Project: Hadoop Chukwa
>          Issue Type: Bug
>          Components: data collection, Data Processors
>            Reporter: Jiaqi Tan
>
> Times in Job History logs are stored in UTC seconds from Epoch, but times in log-based
sources e.g. clienttrace, and the daemon (DataNode, TaskTracker, JobTracker, NameNode) logs
are in local timezones and in ISO-8601 strings, and do not have the timezone they are recorded
in. This leads to inconsistencies when trying to correlate data in time across log-based sources
and Job History data because the timezone of the data for the log-based sources which emit
times in human-readable strings do not record the timezone. 

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