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From Josh Wills <josh.wi...@gmail.com>
Subject Re: CrunchJobHooks.CompletionHook Inefficiency on S3NativeFileSystem
Date Tue, 24 Nov 2015 01:45:18 GMT
(I don't know the answer to this, but as I also now run Crunch on top of
S3, I'm interested in a solution.)

On Mon, Nov 23, 2015 at 5:22 PM, Jeff Quinn <jeff@nuna.com> wrote:

> Hey All,
>
> We have run in to a pretty frustrating inefficiency inside of
> the CrunchJobHooks.CompletionHook#handleMultiPaths.
>
> This method loops over all of the partial output files and moves them to
> their ultimate destination directories,
> calling org.apache.hadoop.fs.FileSystem#rename(org.apache.hadoop.fs.Path,
> org.apache.hadoop.fs.Path) on each partial output in a loop.
>
> This is no problem when the org.apache.hadoop.fs.FileSystem in question is
> HDFS where #rename is a cheap operation, but when an implementation such
> as S3NativeFileSystem is used it is extremely inefficient, as each
> iteration through the loop makes a single blocking S3 API call, and this
> loop can be extremely long when there are many thousands of partial output
> files.
>
> Has anyone dealt with this before / have any ideas to work around?
>
> Thanks!
>
> Jeff
>
>
>
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