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Posted to common-dev@hadoop.apache.org by Yi Gao <yi...@gmail.com> on 2013/09/06 03:39:40 UTC

回复: [jira] [Created] (HADOOP-9937) Improvement of the group information refer frequency


发送自我的HTC S710e

----- Reply message -----
发件人： "Shinichi Yamashita (JIRA)" <ji...@apache.org>
收件人： <co...@hadoop.apache.org>
主题： [jira] [Created] (HADOOP-9937) Improvement of the group information refer frequency
日期： 周五, 9 月 6 日, 2013 年 6:23 上午


Shinichi Yamashita created HADOOP-9937:
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             Summary: Improvement of the group information refer frequency
                 Key: HADOOP-9937
                 URL: https://issues.apache.org/jira/browse/HADOOP-9937
             Project: Hadoop Common
          Issue Type: Improvement
          Components: security
    Affects Versions: 3.0.0
            Reporter: Shinichi Yamashita
            Priority: Minor


The node (e.g. NameNode, ResourceManager) uses UGI.getGroupNames() now to get the information of the user's group who accessed it.
In UGI.getGroupsNames(), synchronized is declared, but UGI instance by various methods each time and the node get different lock in getGroupName().

For example, when cache time limit in userToGroupsMap of Groups expired and the node accepts many requests at the same time, each refers for group information in id command or JNI.
To improve the refer frequency of the group information, it should change about synchronization.

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