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From "Arun C Murthy (JIRA)" <j...@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'
Date Thu, 28 Sep 2006 09:43:51 GMT
    [ http://issues.apache.org/jira/browse/HADOOP-538?page=comments#action_12438384 ] 
            
Arun C Murthy commented on HADOOP-538:
--------------------------------------

Good points Doug; thanks!

Some thoughts...

I like the 'fallback' mechanism, it should ease hadoop adoption for people on heterogenous
environments, I'll get to work on this one.

However I'm a little skeptical about 'ship pre-built libhadoop.so' part for the following
reasons:
a) We will need to maintain versions for different h/w architectures and linux distros (Definition
of 'standard platforms'? -> cygwin and RHEL/ubuntu/FC{4|5}).
b) glibc compatibility (and also stuff like whether it is compiled with -nptl or not and so
on); agreed it isn't very common, but something which might bite us once in a while. (Hmm...
differing glibc across linux distros?)
c) Though we don't have it so far, a single line of C++ code in src/native will make things
far worse due to C++ ABI issues; means we will need to maintain different versions of libhadoop
for gcc-2x, gcc-3x, gcc-4x etc, even for 'standard platforms'.

Hence I'd like to propose we only have the 'fallback' mechanism - if you need libhadoop.so,
please build it yourself. We'll do all we can to ease the second part.

I'll also start work to use the GNU build system (autoconf/automake/libtool) for building
libhadoop.so, this should ease the 'please build it yourself' part for people.

Thoughts?


> 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: 0.7.0
>
>         Attachments: HADOOP-538.patch, 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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