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MapReduce >> mail # user >> use S3 as input to MR job


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Dan Yi 2012-07-20, 00:44
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Harsh J 2012-07-20, 01:33
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Ben Kim 2012-10-02, 10:05
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Re: use S3 as input to MR job
Are you sure that you prepare your MR code to work with mutiple files?
This example (WordCount) works with a single input.

You should take a look to the MultipleInput API for this.
Best wishes

El 02/10/2012 6:05, Ben Kim escribi�:
> I'm having a similar issue
>
> I'm running a wordcount MR as follows
>
>     hadoop jar WordCount.jar wordcount.WordCountDriver
>     s3n://bucket/wordcount/input s3n://bucket/wordcount/output
>
> s3n://bucket/wordcount/input is a s3 object that contains other input
> files.
>
> However I get following NPE error
>
>     12/10/02 18:56:23 INFO mapred.JobClient:  map 0% reduce 0%
>     12/10/02 18:56:54 INFO mapred.JobClient:  map 50% reduce 0%
>             12/10/02 18:56:56 INFO mapred.JobClient: Task Id :
>     attempt_201210021853_0001_m_000001_0, Status : FAILED
>     java.lang.NullPointerException
>             at
>     org.apache.hadoop.fs.s3native.NativeS3FileSystem$NativeS3FsInputStream.close(NativeS3FileSystem.java:106)
>             at
>     java.io.BufferedInputStream.close(BufferedInputStream.java:451)
>             at java.io.FilterInputStream.close(FilterInputStream.java:155)
>             at org.apache.hadoop.util.LineReader.close(LineReader.java:83)
>             at
>     org.apache.hadoop.mapreduce.lib.input.LineRecordReader.close(LineRecordReader.java:144)
>             at
>     org.apache.hadoop.mapred.MapTask$NewTrackingRecordReader.close(MapTask.java:497)
>             at
>     org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:765)
>             at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370)
>             at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
>             at java.security.AccessController.doPrivileged(Native Method)
>             at javax.security.auth.Subject.doAs(Subject.java:396)
>             at
>     org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)
>             at org.apache.hadoop.mapred.Child.main(Child.java:249)
>
>
> MR runs fine if i specify more specific input path such as
> s3n://bucket/wordcount/input/file.txt
> what i want is to be able to pass s3 folders as parameters
> Does anyone knows how to do this?
>
> Best regards,
> Ben Kim
>
>
> On Fri, Jul 20, 2012 at 10:33 AM, Harsh J <[EMAIL PROTECTED]
> <mailto:[EMAIL PROTECTED]>> wrote:
>
>     Dan,
>
>     Can you share your error? The plain .gz files (not .tar.gz) are
>     natively supported by Hadoop via its GzipCodec, and if you are
>     facing an error, I believe its cause of something other than
>     compression.
>
>
>     On Fri, Jul 20, 2012 at 6:14 AM, Dan Yi <[EMAIL PROTECTED]
>     <mailto:[EMAIL PROTECTED]>> wrote:
>
>         i have a MR job to read file on amazon S3 and process the data
>         on local hdfs. the files are zipped text file as .gz. i tried
>         to setup the job as below but it won't work, anyone know what
>         might be wrong? do i need to add extra step to unzip the file
>         first? thanks.
>
>         |String S3_LOCATION = "s3n://access_key:private_key@bucket_name"
>
>         protected void prepareHadoopJob() throws Exception {
>
>              this.getHadoopJob().setMapperClass(Mapper1.class);
>              this.getHadoopJob().setInputFormatClass(TextInputFormat.class);
>
>              FileInputFormat.addInputPath(this.getHadoopJob(), new Path(S3_LOCATION));
>
>              this.getHadoopJob().setNumReduceTasks(0);
>              this.getHadoopJob().setOutputFormatClass(TableOutputFormat.class);
>              this.getHadoopJob().getConfiguration().set(TableOutputFormat.OUTPUT_TABLE, myTable.getTableName());
>              this.getHadoopJob().setOutputKeyClass(ImmutableBytesWritable.class);
>              this.getHadoopJob().setOutputValueClass(Put.class);
>         }|
>
>
>
>
>         *
>         **
>         Dan Yi*| Software Engineer, Analytics Engineering
>         Medio Systems Inc | 701 Pike St. #1500 Seattle, WA 98101
>         */Predictive Analytics for a Connected World/*

Marcos Ortiz Valmaseda,
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