Sean Busbey created HIVE-4329:
---------------------------------
Summary: HCatalog clients can't write to AvroSerde backed tables
Key: HIVE-4329
URL: https://issues.apache.org/jira/browse/HIVE-4329
Project: Hive
Issue Type: Bug
Components: HCatalog, Serializers/Deserializers
Affects Versions: 0.10.0
Environment: discovered in Pig, but it looks like the root cause
impacts all non-Hive users
Reporter: Sean Busbey
Attempting to write to a HCatalog defined table backed by the AvroSerde fails
with the following stacktrace:
{code}
java.lang.ClassCastException: org.apache.hadoop.io.NullWritable cannot be cast
to org.apache.hadoop.io.LongWritable
at
org.apache.hadoop.hive.ql.io.avro.AvroContainerOutputFormat$1.write(AvroContainerOutputFormat.java:84)
at
org.apache.hcatalog.mapreduce.FileRecordWriterContainer.write(FileRecordWriterContainer.java:253)
at
org.apache.hcatalog.mapreduce.FileRecordWriterContainer.write(FileRecordWriterContainer.java:53)
at
org.apache.hcatalog.pig.HCatBaseStorer.putNext(HCatBaseStorer.java:242)
at org.apache.hcatalog.pig.HCatStorer.putNext(HCatStorer.java:52)
at
org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigOutputFormat$PigRecordWriter.write(PigOutputFormat.java:139)
at
org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigOutputFormat$PigRecordWriter.write(PigOutputFormat.java:98)
at
org.apache.hadoop.mapred.MapTask$NewDirectOutputCollector.write(MapTask.java:559)
at
org.apache.hadoop.mapreduce.task.TaskInputOutputContextImpl.write(TaskInputOutputContextImpl.java:85)
{code}
The proximal cause of this failure is that the AvroContainerOutputFormat's
signature mandates a LongWritable key and HCat's FileRecordWriterContainer
forces a NullWritable. I'm not sure of a general fix, other than redefining
HiveOutputFormat to mandate a WritableComparable.
It looks like accepting WritableComparable is what's done in the other Hive
OutputFormats, and there's no reason AvroContainerOutputFormat couldn't also be
changed, since it's ignoring the key. That way fixing things so
FileRecordWriterContainer can always use NullWritable could get spun into a
different issue?
The underlying issue is that AvroContainerOutputFormat doesn't meaningfully
implement getRecordWriter, so fixing the above will just push the failure into
the placeholder RecordWriter.
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