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Posted to common-dev@hadoop.apache.org by "robert Cook (JIRA)" <ji...@apache.org> on 2010/01/26 21:26:34 UTC

[jira] Created: (HADOOP-6512) Complex Writable classes are not thread safe

Complex Writable classes are not thread safe
--------------------------------------------

                 Key: HADOOP-6512
                 URL: https://issues.apache.org/jira/browse/HADOOP-6512
             Project: Hadoop Common
          Issue Type: Bug
          Components: io
    Affects Versions: 0.20.1
         Environment: hadoop 20.1, java 1.6.0_17, fedora
            Reporter: robert Cook


While SequenceFile methods are properly "synchronized", the complex Writable classes are not thread safe.

e.g. ArrayWritable, interleaved in... calls by different threads will scramble input

  public void readFields(DataInput in) throws IOException {
    values = new Writable[in.readInt()];          // construct values
    for (int i = 0; i < values.length; i++) {
      Writable value = WritableFactories.newInstance(valueClass);
      value.readFields(in);                       // read a value
      values[i] = value;                          // store it in values
    }
  }

Please add synchronized prefixes.  Not needed for simple types.

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[jira] Resolved: (HADOOP-6512) Complex Writable classes are not thread safe

Posted by "Chris Douglas (JIRA)" <ji...@apache.org>.
     [ https://issues.apache.org/jira/browse/HADOOP-6512?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Chris Douglas resolved HADOOP-6512.
-----------------------------------

    Resolution: Invalid

I agree with Todd; the caller is responsible for thread safety.

> Complex Writable classes are not thread safe
> --------------------------------------------
>
>                 Key: HADOOP-6512
>                 URL: https://issues.apache.org/jira/browse/HADOOP-6512
>             Project: Hadoop Common
>          Issue Type: Bug
>          Components: io
>    Affects Versions: 0.20.1
>         Environment: hadoop 20.1, java 1.6.0_17, fedora
>            Reporter: robert Cook
>
> While SequenceFile methods are properly "synchronized", the complex Writable classes are not thread safe.
> e.g. ArrayWritable, interleaved in... calls by different threads will scramble input
>   public void readFields(DataInput in) throws IOException {
>     values = new Writable[in.readInt()];          // construct values
>     for (int i = 0; i < values.length; i++) {
>       Writable value = WritableFactories.newInstance(valueClass);
>       value.readFields(in);                       // read a value
>       values[i] = value;                          // store it in values
>     }
>   }
> Please add synchronized prefixes.  Not needed for simple types.

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