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Posted to common-dev@hadoop.apache.org by "Kihwal Lee (Created) (JIRA)" <ji...@apache.org> on 2012/02/17 23:12:57 UTC

[jira] [Created] (HADOOP-8088) User-group mapping cache incorrectly does negative caching on transient failures

User-group mapping cache incorrectly does negative caching on transient failures
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                 Key: HADOOP-8088
                 URL: https://issues.apache.org/jira/browse/HADOOP-8088
             Project: Hadoop Common
          Issue Type: Bug
          Components: security
    Affects Versions: 1.0.0, 0.20.205.0, 0.24.0, 0.23.1, 1.1.0
            Reporter: Kihwal Lee
             Fix For: 0.24.0, 1.1.0, 0.23.2


We've seen a case where some getGroups calls fail when the ldap server or the network has a transient issue. Looking the code, the shell-based and the JNI-based implementation swallow exceptions and return an empty or partial list. The caller, Groups#getGroups() adds this likely empty list into the mapping cache for the user. This will function as negative caching until the cach expires. I don't think we want negative caching here, but even if we do, it should be intelligent enough to distinguish transient failures from ENOENT. The log message in the jni-based imple also needs an improvement. It should print what exception it encountered instead of just saying one happened.

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