Hello! I am serializing Avro GenericRecords with Hadoop MapReduce, and they are generally pretty large (more than 200 fields at times). When calling context.write() in the Mapper/Reducer for the job, sometimes I am met with an UnresolvedUnionException like so:
java.lang.Exception: org.apache.avro.file.DataFileWriter$AppendWriteException: org.apache.avro.UnresolvedUnionException: Not in union ["null","int"]: 123 Sometimes, it's possible to guess which field was being serialized when this exception is thrown, but I find that most of the time I have no idea for which field it is occurring! It could be any of 200+ fields which are specified in the Schema for the GenericRecord as being a ["null", "int"], but it is very difficult to narrow it down. It would be great if the exception could say something like: java.lang.Exception: org.apache.avro.file.DataFileWriter$AppendWriteException: When writing field 'someField': org.apache.avro.UnresolvedUnionException: Not in union ["null","int"]: 123 I don't personally have any example code that can easily reproduce this, but borrowing the code in AVRO-966 ( https://issues.apache.org/jira/browse/AVRO-966) I also see this unclear error message turning up. Is there a way to achieve this easily? Or, would this have to be a new Avro feature, and if so, is it possible? I admit that I don't have a super in-depth knowledge of the inner workings of Avro. Thank you!
