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http://issues.apache.org/jira/browse/HADOOP-619?page=comments#action_12455448 ]
Runping Qi commented on HADOOP-619:
-----------------------------------
A couple of points:
1. specifying input:
I think the user should specify the input files in the following way:
spec_1,spec_2, ...
Each spec above is a "root" directory, with an optional a pttern specification
(regex, or simple wildcad based patterns).
The semantics for a spec is that all the files directly or indirectly under the
root are input files,
as long as the paths match the pattern.
If the pattern is ommitted in the spec, that means all the files under the root
dir are the input files.
Here are a couple of examples:
"foo/" all the files under foo tree
"foo/;*.gz": all the files under foo tree, with extension .gz
"foo/; */bar/*.gz: all the files under foo tree, with extension .gz and with
bar as a intermediate directory.
2. Checking and matching:
The jobclient should check the existence of the root dirs.
If none of the root dirs exists, then the job should fail immediately.
If some root dirs do not exist, the job client should generate warning.
The InputFormatbase should perform the file list generation and matching.
The list of matched files
should be part of the job's status so that the user can examine them
through web UI.
> Unify Map-Reduce and Streaming to take the same globbed input specification
> ---------------------------------------------------------------------------
>
> Key: HADOOP-619
> URL: http://issues.apache.org/jira/browse/HADOOP-619
> Project: Hadoop
> Issue Type: Improvement
> Components: mapred
> Reporter: eric baldeschwieler
> Assigned To: Sanjay Dahiya
>
> Right now streaming input is specified very differently from other map-reduce
> input. It would be good if these two apps could take much more similar input
> specs.
> In particular -input in streaming expects a file or glob pattern while MR
> takes a directory. It would be cool if both could take a glob patern of
> files and if both took a directory by default (with some patern excluded to
> allow logs, metadata and other framework output to be safely stored).
> We want to be sure that MR input is backward compatible over this change. I
> propose that a single file should be accepted as an input or a single
> directory. Globs should only match directories if the paterns is '/'
> terminated, to avoid massive inputs specified by mistake.
> Thoughts?
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