Hi,
I try to create a MapReduce job that calculate the average of values stored in cassandra and write the result back to cassandra (using ColumnFamilyOutputFormat and ColumnFamilyInputFormat). I use the Brisk distribution of Hadoop but I don't know if it's somehow related.
My code is here: http://pastebin.com/8gd21VuP
As I understand in the WordCount example, the first parameters of the map method is the row key and the second one is a map of <column.name, column>. I found confirmation of this in the class ColumnFamilyRecordReader.
But my code didn't works. I dumped the row key and the column name using logger and I saw that both seems to be get_range_slices objects, which is very unexpected.
Here is an example of log (the CF contains 5 rows called row[0-4] with 10 columns each called columnKey[0-9] with value 42 ( * in ascii)):
MAP rowkey: get_range_slicesrow1columnKey0*`columnKey1*acolumnKey2*bcolumnKey3*ccolumnKey4*dcolumnKey5*ecolumnKey6*fcolumnKey7*gcolumnKey8*hcolumnKey9*Hrow2columnKey0*columnKey1*columnKey2*columnKey3*columnKey4*columnKey5*columnKey6*columnKey7*columnKey8*columnKey9*row4columnKey0*pcolumnKey1*qcolumnKey2*rcolumnKey3*XcolumnKey4*YcolumnKey5*ZcolumnKey6*[columnKey7*@columnKey8*AcolumnKey9*Brow3columnKey0*columnKey1*columnKey2*columnKey3*columnKey4*columnKey5*columnKey6*columnKey7*columnKey8*columnKey9*row0columnKey0*columnKey1*:columnKey2*:!columnKey3*:"columnKey4*:#columnKey5*>columnKey6*>columnKey7*>columnKey8*>columnKey9*>
MAP columnKey: get_range_slicesrow1columnKey0*`columnKey1*acolumnKey2*bcolumnKey3*ccolumnKey4*dcolumnKey5*ecolumnKey6*fcolumnKey7*gcolumnKey8*hcolumnKey9*Hrow2columnKey0*columnKey1*columnKey2*columnKey3*columnKey4*columnKey5*columnKey6*columnKey7*columnKey8*columnKey9*row4columnKey0*pcolumnKey1*qcolumnKey2*rcolumnKey3*XcolumnKey4*YcolumnKey5*ZcolumnKey6*[columnKey7*@columnKey8*AcolumnKey9*Brow3columnKey0*columnKey1*columnKey2*columnKey3*columnKey4*columnKey5*columnKey6*columnKey7*columnKey8*columnKey9*row0columnKey0*columnKey1*:columnKey2*:!columnKey3*:"columnKey4*:#columnKey5*>columnKey6*>columnKey7*>columnKey8*>columnKey9*>

I can't understand why I get this instead of row key and column key, if anybody have an idea?
Silvère