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Posted to issues@kylin.apache.org by "kangkaisen (JIRA)" <ji...@apache.org> on 2016/12/02 02:18:58 UTC
[jira] [Assigned] (KYLIN-2242) Directly write hdfs file in reducer
is dangerous
[ https://issues.apache.org/jira/browse/KYLIN-2242?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
kangkaisen reassigned KYLIN-2242:
---------------------------------
Assignee: kangkaisen (was: Dong Li)
> Directly write hdfs file in reducer is dangerous
> ------------------------------------------------
>
> Key: KYLIN-2242
> URL: https://issues.apache.org/jira/browse/KYLIN-2242
> Project: Kylin
> Issue Type: Bug
> Components: Job Engine
> Affects Versions: v1.6.0
> Reporter: kangkaisen
> Assignee: kangkaisen
>
> currently, Kylin directly write hdfs file in {{FactDistinctColumnsReducer}}, which is dangerous because the MapReduce Speculative Execution will result in more than one reducers write the same hdfs file at the same time.
> After KYLIN-2217, I think this issue will occur with higher probability. we should output the value by {{context.wirte}} in reducer.
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