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Date: Tue, 7 Nov 2006 14:56:54 -0800 (PST)
From: "Owen O'Malley (JIRA)" <jira@apache.org>
To: hadoop-dev@lucene.apache.org
Subject: [jira] Commented: (HADOOP-538) Implement a nio's 'direct buffer'
 based wrapper over zlib to improve performance of
 java.util.zip.{De|In}flater as a 'custom codec'
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    [ http://issues.apache.org/jira/browse/HADOOP-538?page=comments#action_12447951 ] 
            
Owen O'Malley commented on HADOOP-538:
--------------------------------------

The ZlibCompressor has dead nativeZlibLoaded code.

The ZlibFactory getGzip{Decom,Com}pressor methods should never return null, because their contract should be that they always return a valid implementation regardless of whether the native library was loaded. I see that the problem is that you want to use the native Gzip stream stuff, which doesn't provide a {com,decom}pressor. I guess I'd vote for just using:

public CompressionInputStream createInputStream(InputStream in) throws IOException {
  if (ZlibFactory.isNativeZlibLoaded()) {
    return new DecompressorStream(...);
  } else {
    return new GzipInputStream(in);
  }
}

and removing the extra ZlibFactory.getGzip* methods.


> Implement a nio's 'direct buffer' based wrapper over zlib to improve performance of java.util.zip.{De|In}flater as a 'custom codec'
> -----------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: HADOOP-538
>                 URL: http://issues.apache.org/jira/browse/HADOOP-538
>             Project: Hadoop
>          Issue Type: Improvement
>    Affects Versions: 0.6.1
>            Reporter: Arun C Murthy
>         Assigned To: Arun C Murthy
>             Fix For: 0.9.0
>
>         Attachments: HADOOP-538.patch, HADOOP-538_20061005.tgz, HADOOP-538_20061011.tgz, HADOOP-538_20061026.tgz, HADOOP-538_20061030.tgz, HADOOP-538_20061107.tgz, HADOOP-538_benchmarks.tgz
>
>
> There has been more than one instance where java.util.zip's {De|In}flater classes perform unreliably, a simple wrapper over zlib-1.2.3 (latest stable) using java.nio.ByteBuffer (i.e. direct buffers) should go a long way in alleviating these woes.

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