Error in pig while loading data

Question

I am using ubuntu 12.02 32bit and have installed hadoop2.2.0 and pig 0.12 successfully. Hadoop runs properly on my system.

However, whenever I run this command :

data = load 'atoz.csv' using PigStorage(',')  as (aa1:int, bb1:int, cc1:int, dd1:chararray);            
dump data;

I'm getting the following error :

ERROR org.apache.hadoop.mapreduce.lib.jobcontrol.JobControl - Error whiletrying to run jobs.java.lang.IncompatibleClassChangeError: Found interface org.apache.hadoop.mapreduce.JobContext, but class was expected.

Here is the full stacktrace :

> 2014-01-23 10:41:44,998 [main] INFO  org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher- 1 map-reduce job(s) waiting for submission.
>             2014-01-23 10:41:45,000 [Thread-9] INFO  org.apache.hadoop.metrics.jvm.JvmMetrics - Cannot initialize JVM
> Metrics with processName=JobTracker, sessionId= - already initialized
>             2014-01-23 10:41:45,001 [Thread-9] ERROR org.apache.hadoop.mapreduce.lib.jobcontrol.JobControl - Error while
> trying to run jobs.
>             java.lang.IncompatibleClassChangeError: Found interface org.apache.hadoop.mapreduce.JobContext, but class was expected
>             at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigOutputFormat.setupUdfEnvAndStores(PigOutputFormat.java:225)
>             at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigOutputFormat.checkOutputSpecs(PigOutputFormat.java:186)
>             at org.apache.hadoop.mapreduce.JobSubmitter.checkSpecs(JobSubmitter.java:456)
>             at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:342)
>             at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1268)
>             at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1265)
>             at java.security.AccessController.doPrivileged(Native Method)
>             at javax.security.auth.Subject.doAs(Subject.java:415)
>             at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1491)
>             at org.apache.hadoop.mapreduce.Job.submit(Job.java:1265)
>             at org.apache.hadoop.mapreduce.lib.jobcontrol.ControlledJob.submit(ControlledJob.java:335)
>             at org.apache.hadoop.mapreduce.lib.jobcontrol.JobControl.run(JobControl.java:240)
>             at java.lang.Thread.run(Thread.java:724)
>             at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher$1.run(MapReduceLauncher.java:260)
>             2014-01-23 10:41:45,498 [main] INFO  org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher
> - 0% complete
>             2014-01-23 10:41:45,502 [main] INFO  org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher
> - job null has failed! Stop running all dependent jobs
>             2014-01-23 10:41:45,503 [main] INFO  org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher
> - 100% complete
>             2014-01-23 10:41:45,507 [main] ERROR org.apache.pig.tools.pigstats.SimplePigStats - ERROR 2997: Unable to
> recreate exception from backend error: Unexpected System Error
> Occured: java.lang.IncompatibleClassChangeError: Found interface
> org.apache.hadoop.mapreduce.JobContext, but class was expected
>             at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigOutputFormat.setupUdfEnvAndStores(PigOutputFormat.java:225)
>             at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigOutputFormat.checkOutputSpecs(PigOutputFormat.java:186)
>             at org.apache.hadoop.mapreduce.JobSubmitter.checkSpecs(JobSubmitter.java:456)
>             at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:342)
>             at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1268)
>             at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1265)
>             at java.security.AccessController.doPrivileged(Native Method)
>             at javax.security.auth.Subject.doAs(Subject.java:415)
>             at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1491)
>             at org.apache.hadoop.mapreduce.Job.submit(Job.java:1265)
>             at org.apache.hadoop.mapreduce.lib.jobcontrol.ControlledJob.submit(ControlledJob.java:335)
>             at org.apache.hadoop.mapreduce.lib.jobcontrol.JobControl.run(JobControl.java:240)
>             at java.lang.Thread.run(Thread.java:724)
>             at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher$1.run(MapReduceLauncher.java:260)
2014-01-23 10:41:45,507 [main] ERROR org.apache.pig.tools.pigstats.PigStatsUtil - 1 map reduce job(s)
> failed!
>             2014-01-23 10:41:45,507 [main] INFO  org.apache.pig.tools.pigstats.SimplePigStats - Detected Local mode.
> Stats reported below may be incomplete
>             2014-01-23 10:41:45,508 [main] INFO  org.apache.pig.tools.pigstats.SimplePigStats - Script Statistics:
HadoopVersion    PigVersion    UserId    StartedAt    FinishedAt    Features
>             2.2.0    0.10.1    hardik    2014-01-23 10:41:44    2014-01-23 10:41:45    UNKNOWN
 Failed!
Failed Jobs:
JobId    Alias    Feature    Message    Outputs
N/A    aatoz    MAP_ONLY    Message: Unexpected System Error Occured: java.lang.IncompatibleClassChangeError: Found interface
> org.apache.hadoop.mapreduce.JobContext, but class was expected
>             at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigOutputFormat.setupUdfEnvAndStores(PigOutputFormat.java:225)
>             at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigOutputFormat.checkOutputSpecs(PigOutputFormat.java:186)
>             at org.apache.hadoop.mapreduce.JobSubmitter.checkSpecs(JobSubmitter.java:456)
>             at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:342)
>             at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1268)
>             at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1265)
>             at java.security.AccessController.doPrivileged(Native Method)
>             at javax.security.auth.Subject.doAs(Subject.java:415)
>             at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1491)
>             at org.apache.hadoop.mapreduce.Job.submit(Job.java:1265)
>             at org.apache.hadoop.mapreduce.lib.jobcontrol.ControlledJob.submit(ControlledJob.java:335)
>             at org.apache.hadoop.mapreduce.lib.jobcontrol.JobControl.run(JobControl.java:240)
>             at java.lang.Thread.run(Thread.java:724)
>             at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher$1.run(MapReduceLauncher.java:260)
>             file:/tmp/temp1979716161/tmp-189979005,
Input(s):
Failed to read data from "file:///home/hardik/pig10/bin/input/atoz.csv"
Output(s):
             Failed to produce result in "file:/tmp/temp1979716161/tmp-189979005"
Job DAG:
null
2014-01-23 10:41:45,509 [main] INFO  org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher
 Failed! 2014-01-23 10:41:45,510 [main] ERROR org.apache.pig.tools.grunt.Grunt - ERROR 1066: Unable to open iterator
> for alias aatoz
>             Details at logfile: /home/hardik/pig10/bin/pig_1390453192689.log
>     </i>

Gaberones

Please fix the question format... – Lilli

For people who found this post when looking for ERROR 1066: Unable to open iterator for alias here is a generic solution. – Predict

Answer 1

Apache Pig 0.12.0 expects an older version of Hadoop by default. You must recompile Pig for Hadoop 2.2.0 and replace two jars with new pig-0.12.1-SNAPSHOT.jar and pig-0.12.1-SNAPSHOT-withouthadoop.jar.

For recompilation unpack the pig archive, go to the directory "pig-0.12.0" and just run:

ant clean jar-all -Dhadoopversion=23

Auria

Answer 2

just building with command "ant clean jar-all -Dhadoopversion=23" is not enough if you are using maven dependencies in your project. You will need to install the jar created by this in your local maven repo or use this dependency (notice "classifier" tag for hadoop2) in your pom.xml

<dependency>
<groupId>org.apache.pig</groupId>
<artifactId>pig</artifactId>
<classifier>h2</classifier>
<version>0.13.0</version>
</dependency>

Lively

Answer 3

I've resolved it in another way.

I got the same problem on CDH4.4 & Pig 0.11.0 when my Pig script was invoking a UDF from my java project which was compiled using Maven. I've visited /usr/lib/pig/conf/build.properties file. Verified the versions mentioned against hadoop-core, hadoop-common, hadoop-mapreduce properties. Ensured that all these artifacts with same versions are included as dependencies in my java project's POM.xml file.

( Infact hadoop-mapreduce has 6 artifact Ids as per http://www.cloudera.com/content/cloudera-content/cloudera-docs/CDH4/4.2.0/CDH4-Installation-Guide/cdh4ig_topic_31.html. I've included all of them in the dependencies list).

After building my project's jar file with these POM settings, Pig script was able to invoke UDF without any problem.

Brnaby

Answer 4

This is your clue ERROR org.apache.hadoop.mapreduce.lib.jobcontrol.JobControl - Error while trying to run jobs. java.lang.IncompatibleClassChangeError: Found interface org.apache.hadoop.mapreduce.JobContext, but class was expected. The interface "jobcontrol" is looking for a certain class and doesn't find it.

Secret

Answer 5

Just caught the same exception, trying to run script with my UDF on Hadoop 2x.

In latest release 0.14 and current trunk 0.15, ant target jar-all is missing. So if you are building from sources, you can use

jar-h12 Create pig for both Hadoop 1 and Hadoop 2

or

ant jar -Dhadoopversion=23

or simply download compatible version from Maven Central.

In my case it was pig-0.14.0-h2.jar

Pentacle

Answer 6

This problem also arises with any hadoop version above 2.2. An easier way is to install Pig version 0.15. They have solved this problem in this version.

Solvent