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Avro and Oozie Map Reduce action
M, Paul 2013-03-12, 22:35
Hello,

I am trying to run an M/R job with Avro serialization via Oozie.  I've made some progress in the workflow.xml, however I am still running into the following error.  Any thoughts?  I believe it may have to do with the io.serializations property below.   FYI, I am using CDH 4.2.0 mr1.

2013-03-12 15:24:32,334 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201303111118_0080_m_000000_3: java.lang.NullPointerException
at org.apache.hadoop.mapred.MapTask.getSplitDetails(MapTask.java:356)
at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:389)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:333)
at org.apache.hadoop.mapred.Child$4.run(Child.java:268)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1407)
at org.apache.hadoop.mapred.Child.main(Child.java:262)
<action name="mr-node">
<map-reduce>
<job-tracker>${jobTracker}</job-tracker>
<name-node>${nameNode}</name-node>
<prepare>
<delete path="${nameNode}/user/${wf:user()}/${outputDir}" />
</prepare>
<configuration>
<property>
<name>mapred.job.queue.name</name>
<value>${queueName}</value>
</property>

<property>
<name>mapreduce.reduce.class</name>
<value>org.apache.avro.mapred.HadoopReducer</value>
</property>
<property>
<name>mapreduce.map.class</name>
<value>org.apache.avro.mapred.HadoopMapper</value>
</property>
<property>
<name>avro.reducer</name>
<value>org.my.project.mapreduce.CombineAvroRecordsByHourReducer
</value>
</property>

<property>
<name>avro.mapper</name>
<value>org.my.project.mapreduce.ParseMetadataAsTextIntoAvroMapper
</value>
</property>
<property>
<name>mapreduce.inputformat.class</name>
<value>org.my.project.mapreduce.NonSplitableInputFormat</value>
</property>

<!-- Key Value Mapper -->
<property>
<name>avro.output.schema</name>
<value>{"type":"record","name":"Pair","namespace":"org.apache.avro.mapred","fields":..."}]}
</value>
</property>
<property>
<name>mapred.mapoutput.key.class</name>
<value>org.apache.avro.mapred.AvroKey</value>
</property>
<property>
<name>mapred.mapoutput.value.class</name>
<value>org.apache.avro.mapred.AvroValue</value>
</property>
<property>
<name>avro.schema.output.key</name>
<value>{"type":"record","name":"DataRecord","namespace":...]}]}
</value>
</property>

<property>
<name>mapreduce.outputformat.class</name>
<value>org.apache.hadoop.mapreduce.lib.output.TextOutputFormat
</value>
</property>

<property>
<name>mapred.output.key.comparator.class</name>
<value>org.apache.avro.mapred.AvroKeyComparator</value>
</property>

<property>
<name>io.serializations</name>
<value>org.apache.avro.mapred.AvroSerialization, avro.serialization.key.reader.schema, avro.serialization.value.reader.schema, avro.serialization.key.writer.schema,avro.serialization.value.writer.schema
</value>
</property>

<property>
<name>mapred.map.tasks</name>
<value>1</value>
</property>

<!--Input/Output -->
<property>
<name>mapred.input.dir</name>
<value>/user/${wf:user()}/input/</value>
</property>
<property>
<name>mapred.output.dir</name>
<value>/user/${wf:user()}/${outputDir}</value>
</property>
</configuration>
</map-reduce>