I'm having a strange problem running a hive query against my Datastax Enterprise 1.0 cluster:
If I use the automatic cassandra to Hive mapping, then I can't execute a query with a group by:
select myfield, count(*) from mytable group by myfield;
it fails with the following error:
FAILED: Hive Internal Error: java.lang.NullPointerException(null) java.lang.NullPointerException at org.apache.hadoop.hive.ql.exec.Utilities.getColumnNamesFromSortCols(Utilities.java:1314)
Just doing a select on myfield works (so the column name is valid), it's only when it's in a group by that it doesn't seem to work.
I tried doing a manual mapping of the column family to a hive table. In that case, i can execute the query above BUT all my numeric columns (ints and bigints) show up in Hive as null despite showing up correctly in Cassandra and in the automapped table. I did a
describe extended mytable on both the auto-created table and the manually created table and verified that the datatypes match for all the columns.
Any thoughts would be greatly appreciated.