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https://issues.apache.org/jira/browse/HDFS-573?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14082944#comment-14082944
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Stephen Bovy commented on HDFS-573:
-----------------------------------
Thanks again for the opportunity to share experience and insights in the use
of libhdfs.
I know some of my comments are off-topic. Maybe we could open another Jira to
discuss thread/performance issues.
I would be happy to post some code slices to demonstrate and explain the issues.
I did find a small bug in the unix thread code in "JNIEnv* getJNIEnv(void)"
>>>>>>>
tls->env = env;
// note this was in the wrong location and has been moved
#ifdef HAVE_BETTER_TLS
quickTls = tls;
return env;
#endif
// note this was in the wrong location and has been moved
ret = pthread_setspecific ( hdfs_gTlsKey, tls );
if (ret) {
fprintf(stderr, "getJNIEnv: pthread_setspecific failed with "
"error code %d\n", ret);
hdfsThreadDestructor(tls);
return NULL;
}
#endif // endif save unix thread local storage
return env;
}
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
> Porting libhdfs to Windows
> --------------------------
>
> Key: HDFS-573
> URL: https://issues.apache.org/jira/browse/HDFS-573
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: libhdfs
> Environment: Windows, Visual Studio 2008
> Reporter: Ziliang Guo
> Assignee: Chris Nauroth
> Attachments: HDFS-573.1.patch
>
> 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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