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https://issues.apache.org/jira/browse/HDFS-573?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13828437#comment-13828437
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Stephen Bovy commented on HDFS-573:
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Darn, I just re-did all the work you guys did !!
Is their anyone out there still interested in this ??
What hashing fucntions did you use ??
I usesd ut-hash
Any suggestions would be appreciated
It is a pain in the but making "c" code look like C code is supposed to
look !!
I worked off the 2.0 branch and unfortunately more linux only
anachronisisms were added
Hard-coded linux only err-no yikes !!
I have some serious performance questions about the hashing functions
Why not use Thread Local storage for the hashing table , then we can avoid
the performance hit
from locks we do not need to use ???
The jvm init code should not be imbedded into every function call many of
these functions will be used in loops
The jvm init should be in a stand alone function that is called only once
to init the library.
Then we can use a global variable for the jvm * and the fucntion to discover
the count of
jvm's is not needed .
The jvm attach functionallity should only be invoked if threads are used
otherwise it is another
useless perfromance killer
> Porting libhdfs to Windows
> --------------------------
>
> Key: HDFS-573
> URL: https://issues.apache.org/jira/browse/HDFS-573
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs-client
> Environment: Windows, Visual Studio 2008
> Reporter: Ziliang Guo
> Original Estimate: 336h
> Remaining Estimate: 336h
>
> The current C code in libhdfs is written using C99 conventions and also uses
> a few POSIX specific functions such as hcreate, hsearch, and pthread mutex
> locks. To compile it using Visual Studio would require a conversion of the
> code in hdfsJniHelper.c and hdfs.c to C89 and replacement/reimplementation of
> the POSIX functions. The code also uses the stdint.h header, which is not
> part of the original C89, but there exists what appears to be a BSD licensed
> reimplementation written to be compatible with MSVC floating around. I have
> already done the other necessary conversions, as well as created a simplistic
> hash bucket for use with hcreate and hsearch and successfully built a DLL of
> libhdfs. Further testing is needed to see if it is usable by other programs
> to actually access hdfs, which will likely happen in the next few weeks as
> the Condor Project continues with its file transfer work.
> In the process, I've removed a few what I believe are extraneous consts and
> also fixed an incorrect array initialization where someone was attempting to
> initialize with something like this: JavaVMOption options[noArgs]; where
> noArgs was being incremented in the code above. This was in the
> hdfsJniHelper.c file, in the getJNIEnv function.
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