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Posted to hdfs-dev@hadoop.apache.org by "Daryn Sharp (JIRA)" <ji...@apache.org> on 2014/11/24 18:10:12 UTC

[jira] [Created] (HDFS-7435) PB encoding of block reports is very inefficient

Daryn Sharp created HDFS-7435:
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             Summary: PB encoding of block reports is very inefficient
                 Key: HDFS-7435
                 URL: https://issues.apache.org/jira/browse/HDFS-7435
             Project: Hadoop HDFS
          Issue Type: Improvement
          Components: datanode, namenode
    Affects Versions: 2.0.0-alpha, 3.0.0
            Reporter: Daryn Sharp
            Assignee: Daryn Sharp
            Priority: Critical


Block reports are encoded as a PB repeating long.  Repeating fields use an {{ArrayList}} with default capacity of 10.  A block report containing tens or hundreds of thousand of longs (3 for each replica) is extremely expensive since the {{ArrayList}} must realloc many times.  Also, decoding repeating fields will box the primitive longs which must then be unboxed.



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