@SuppressWarnings("unchecked")
    public CassandraJavaPairRDD<K, V> select(ColumnRef... selectionColumns) {
        Seq<ColumnRef> columnRefs = JavaApiHelper.toScalaSeq(selectionColumns);
        CassandraRDD<Tuple2<K, V>> newRDD = rdd().select(columnRefs);
        return wrap(newRDD);
    }
@ SuppressWarnings ( "unchecked" ) public CassandraJavaPairRDD < K , V > select ( ColumnRef ... selectionColumns ) { Seq < ColumnRef > columnRefs = JavaApiHelper . toScalaSeq ( selectionColumns ) ; CassandraRDD < Tuple2 < K , V > > newRDD = rdd ( ) . select ( columnRefs ) ; return wrap ( newRDD ) ; }
Narrows down the selected set of columns.
<p/>
Use this for better performance, when you don't need all the columns in the result RDD. When
called multiple times, it selects the subset of the already selected columns, so after a column
was removed by the previous {@code select} call, it is not possible to add it back.