Unexpected error during execution

["Barreto, Rafael" <ra...@thebackplane.com>]

Hey people,

I'm facing a weird problem running a Pig script on EMR. It fails with
this error message:

2013-03-29 21:07:15,929 [main] ERROR org.apache.pig.tools.grunt.Grunt
- ERROR 2043: Unexpected error during execution.

However, the output is correctly produced and all jobs are reported to
be completed with success. In my investigation I ended up checking the
file

jobs/job_201303292045_0038_1364591135564_hadoop_PigLatin%253Aget%255Ftime%255Fon%255Fsite.pig

produced by the EMR logs. This is for the last job and it contains a
lot of messages like this:

MapAttempt TASK_TYPE="MAP" TASKID="task_201303292045_0038_m_000084"
TASK_ATTEMPT_ID="attempt_201303292045_0038_m_000084_1"
TASK_STATUS="FAILED" FINISH_TIME="1364591223800"
HOSTNAME="10\.6\.179\.195" ERROR="java\.io\.IOException: File already
exists:s3://backplane-analytics/batch_results/20130329-204202190520/get_time_on_site/part-m-00084
	at org\.apache\.hadoop\.fs\.s3native\.NativeS3FileSystem\.create(NativeS3FileSystem\.java:647)
	at org\.apache\.hadoop\.fs\.FileSystem\.create(FileSystem\.java:557)
	at org\.apache\.hadoop\.fs\.FileSystem\.create(FileSystem\.java:538)
	at org\.apache\.hadoop\.fs\.FileSystem\.create(FileSystem\.java:445)
	at org\.apache\.pig\.backend\.hadoop\.executionengine\.mapReduceLayer\.PigTextOutputFormat\.getRecordWriter(PigTextOutputFormat\.java:98)
	at org\.apache\.pig\.backend\.hadoop\.executionengine\.mapReduceLayer\.PigOutputFormat\.getRecordWriter(PigOutputFormat\.java:84)
	at org\.apache\.hadoop\.mapred\.MapTask$NewDirectOutputCollector\.<init>(MapTask\.java:635)
	at org\.apache\.hadoop\.mapred\.MapTask\.runNewMapper(MapTask\.java:760)
	at org\.apache\.hadoop\.mapred\.MapTask\.run(MapTask\.java:375)
	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:1132)
	at org\.apache\.hadoop\.mapred\.Child\.main(Child\.java:249)

I don't have any clue to what could be happening since there's no
explicit error message.

Also, it's relavant to say I'm using datafu's StreamingQuantile UDF.
When I don't use this UDF, it runs ok. So... somehow, this is related
to StreamingQuantile, but since there's no error message, I can't
think of what could go wrong and fix it.

Do you guys have any clue about it?

Thanks a lot in advance,
Rafael