http://issues.apache.org/jira/browse/MAPREDUCE-370
You'll have to work around for now / try to apply patch.
Amogh
On 12/9/09 8:54 PM, "Geoffry Roberts" <geoffry.robe...@gmail.com> wrote:
Aaron,
I am using 0.20.1 and I'm not finding org.apache.hadoop.mapreduce.
lib.output.MultipleOutputs. I'm using the download page where the tar ball is
dated from Sep.09.
Sounds like I need to look at the code repository.
On Tue, Dec 8, 2009 at 1:39 PM, Aaron Kimball <aa...@cloudera.com> wrote:
Geoffry,
There are two MultipleOutputs implementations; one for the new API, one for the
old one.
The new API (org.apache.hadoop.mapreduce.lib.output.MultipleOutputs) does not
have a getCollector() method. This is intended to work with
org.apache.hadoop.mapreduce.Mapper and its associated Context object.
The old API implementation of MO (org.apache.hadoop.mapred.lib.MultipleOutputs)
is intended to work with org.apache.hadoop.mapred.Mapper, Reporter, and friends.
If you're going to use the new org.apache.hadoop.mapreduce-based code, you
should not need to import anything in the mapred package. That having been said
-- I just realized that the new-API-compatible MultipleOutputs implementation
is not in Hadoop 0.20. It's only in the unreleased 0.21. If you're using 0.20,
you should probably stick with the old API for your process.
Cheers,
- Aaron
On Tue, Dec 8, 2009 at 12:40 PM, Geoffry Roberts <geoffry.robe...@gmail.com>
wrote:
All,
This one has me stumped.
What I want to do is output from my reducer multiple files, one for each key
value. I also want to avoid any deprecated parts of the API.
As suggested, I switched from using MultipleTextOutputFormat to MultipleOutputs
but have run into an impasse. MultipleOutputs' getCollector method requires a
Reporter as a parameter, but as far as I can tell, the API doesn't support
this. The only reporter I can find is in the context object, but is declared
protected.
Am I stuck? or just missing something?
My code:
@Override
public void reduce(Text key, Iterable<Text> values, Context context)
throws IOException {
String fileName = key.toString();
MultipleOutputs.addNamedOutput((JobConf)
context.getConfiguration(), fileName, OutputFormat.class, Text.class,
Text.class);
mos = new MultipleOutputs((JobConf) context.getConfiguration());
for (Text line : values) {
// This is the problem line:
mos.getCollector(fileName, <reporter goes here>).collect(
key, line);
}
mos.close();
}
On Mon, Oct 5, 2009 at 11:17 AM, Aaron Kimball <aa...@cloudera.com> wrote:
Geoffry,
The new API comes with a related OF, called MultipleOutputs
(o.a.h.mapreduce.lib.output.MultipleOutputs). You may want to look into using
this instead.
- Aaron
On Tue, Sep 29, 2009 at 4:44 PM, Geoffry Roberts <geoffry.robe...@gmail.com>
wrote:
All,
What I want to do is output from my reducer multiple files one for each key
value.
Can this still be done in the current API?
It seems that using MultipleTextOutputFormat requires one to use deprecated
parts of API.
It this correct?
I would like to use the class or its equivalent and stay off anything
deprecated.
Is there a work around?
In the current API one uses Job and a class derived from the class
org.apache.hadoop.mapreduce.OutputFormat. MultipleTextOutputFormat does not
derive from this class.
Job.setOutputFormatClass(Class<? extends
org.apache.hadoop.mapreduce.OutputFormat>);
In the Old, deprecated API, one uses JobConf and an implementation of the
interface org.apache.hadoop.mapred.OutputFormat. MultipleTextOutputFormat is
just such an implementation.
JobConf.setOutputFormat(Class<? extends org.apache.hadoop.mapred .OutputFormat);
