column-based mapreduce

[Mattar, Marwan]

Hi,

I'm new to Hive and was wondering if anyone knows why nextColumnsBatch() in 
RCFile.Reader has been deprecated? I'd like to write a MapReduce where the 
mapper receives an entire column at a time (more specifically, the key is the 
column ID and the value is the column values for that row batch). Writing a 
column-reader class (instead of the existing record reader 
RCFIleMapReduceRecordReader) that uses getColumn() and nextColumnsBatch() seems 
like the natural choice. Any pointers are appreciated (particularly if there is 
an existing class/utility that achieves this).

Thanks,
Marwan