private void warn(String msg) {
    SessionState.getConsole().printInfo(String.format("Warning: %s", msg));
  }
Construct the data structures containing ExprNodeDesc for partition
columns and order columns. Use the input definition to construct the list
of output columns for the ReduceSinkOperator
ql/src/java/org/apache/hadoop/hive/ql/parse/SemanticAnalyzer.java