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https://issues.apache.org/jira/browse/HADOOP-9981?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13772403#comment-13772403
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Andrew Wang commented on HADOOP-9981:
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Hey Kihwal,
We could definitely use {{lstat(2)}} system call instead of {{stat(1)}}, it
just requires a bit more work. {{lstat(2)}} only provides the uid and gid, so
these would need to be translated into string names via {{getpwnam}} and
{{getgrname}}. It'd also require calling {{readlink(2)}} to get the link target
if it's a link. I agree we can keep the existing behavior as a fallback for not
having native code.
As a side note, all of this should really be a fallback for JDK7's lstat, which
we theoretically should be allowed to use since JDK6 is EOL.
> Listing in RawLocalFileSystem is inefficient
> --------------------------------------------
>
> Key: HADOOP-9981
> URL: https://issues.apache.org/jira/browse/HADOOP-9981
> Project: Hadoop Common
> Issue Type: Bug
> Affects Versions: 2.3.0
> Reporter: Kihwal Lee
> Priority: Critical
>
> After HADOOP-9652, listStatus() or globStatus() calls against a local file
> system directory is very slow. A user was loading data from local file
> system to Hive and it took about 30 seconds. The same operation took less
> than a second pre-HADOOP-9652.
> The input path had many other files beside the input files and strace showed
> that fork & exec of stat against each and every one of them. jstack confirmed
> that this was being done from getNativeFileLinkStatus().
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