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Posted to issues@impala.apache.org by "Joe McDonnell (JIRA)" <ji...@apache.org> on 2017/11/22 00:47:00 UTC

[jira] [Created] (IMPALA-6232) Short circuit reads disabled when using Impala HDFS file handle cache

Joe McDonnell created IMPALA-6232:
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             Summary: Short circuit reads disabled when using Impala HDFS file handle cache
                 Key: IMPALA-6232
                 URL: https://issues.apache.org/jira/browse/IMPALA-6232
             Project: IMPALA
          Issue Type: Bug
          Components: Backend
    Affects Versions: Impala 2.10.0
            Reporter: Joe McDonnell
            Assignee: Joe McDonnell
            Priority: Blocker


In Impala 2.10, the HDFS file handle cache was enabled by default. However, testing has revealed that in cases where files are overwritten or appended, the file handle can encounter an error that causes HDFS to disable short circuit reads for 10 minutes. See [HDFS-12528|https://issues.apache.org/jira/browse/HDFS-12528].

Due to this performance impact and the associated unpredictability, Impala should disable the file handle cache by default until this issue is resolved.



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