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https://issues.apache.org/jira/browse/YARN-4958?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15258754#comment-15258754
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Daniel Templeton commented on YARN-4958:
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bq. l.242-243: Would it be simpler to reset current to the parent directory and
simply invoke ancestorsHaveExecutePermissions() on it instead? Then,
getFileStatus doesn't need to change, and the stat cache would also have only
real paths (i.e. no "*" paths). Thoughts?
I can't as easily do the path manipulation above the level of
{{getFileStatus()}} because we're dealing with a URI above that. The net
result of the current code, though, is that the wildcard path is swapped with
its parent inside {{getFileStatus()}}, and only the parent directory is added
to the stat cache. Looks like there was a bug there, though, that caused a
wildcard path to always have a cache miss.
bq. l.323-329: Would there be a case where there can be multiple attempts for
the same directory? Is it for the case both "dir" and "dir/*" are included in
cache.files? I'm not sure if you're addressing a new concern or an existing one.
It's both. The current behavior is to quietly overwrite a duplicate link.
That seems like a bad idea.
l.338-341: Why would there be a wildcard for the paths (which come from
mapreduce.job.classpath.files)?
Good point. I got a little overzealous. :) I'll remove that part in the next
patch.
> The file localization process should allow for wildcards to reduce the
> application footprint in the state store
> ---------------------------------------------------------------------------------------------------------------
>
> Key: YARN-4958
> URL: https://issues.apache.org/jira/browse/YARN-4958
> Project: Hadoop YARN
> Issue Type: Improvement
> Components: nodemanager
> Affects Versions: 2.8.0
> Reporter: Daniel Templeton
> Assignee: Daniel Templeton
> Priority: Critical
> Attachments: YARN-4958.001.patch
>
>
> When using the -libjars option to add classes to the classpath, every library
> so added is explicitly listed in the {{ContainerLaunchContext}}'s local
> resources even though they're all uploaded to the same directory in HDFS.
> When using tools like Crunch without an uber JAR or when trying to take
> advantage of the shared cache, the number of libraries can be quite large.
> We've seen many cases where we had to turn down the max number of
> applications to prevent ZK from running out of heap because of the size of
> the state store entries.
> Rather than listing all files independently, this JIRA proposes to have the
> NM allow wildcards in the resource localization paths. Specifically, we
> propose to allow a path to have a final component (name) set to "*", which is
> interpreted by the NM as "download the full directory and link to every file
> in it from the job's working directory." This behavior is the same as the
> current behavior when using -libjars, but avoids explicitly listing every
> file.
> This JIRA does not attempt to provide more general purpose wildcards, such as
> "\*.jar" or "file\*", as having multiple entries for a single directory
> presents numerous logistical issues.
> This JIRA also does not attempt to integrate with the shared cache. That
> work will be left to a future JIRA. Specifically, this JIRA only applies
> when a full directory is uploaded. Currently the shared cache does not
> handle directory uploads.
> This JIRA proposes to allow for wildcards both in the internal processing of
> the -libjars switch and in paths added through the {{Job}} and
> {{DistributedCache}} classes.
> The proposed approach is to treat a path, "dir/\*", as "dir" for purposes of
> all file verification and localization. In the final step, the NM will query
> the localized directory to get a list of the files in "dir" such that each
> can be linked from the job's working directory. Since $PWD/\* is always
> included on the classpath, all JAR files in "dir" will be in the classpath.
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