@SuppressWarnings("NumericCastThatLosesPrecision")
  static int segment(long index) {
    return (int) (index >>> SEGMENT_SHIFT);
  }
Computes the segment associated with a given index.

@param index an index into a big array.
@return the associated segment.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/operator/source/relational/aggregation/grouped/array/BigArrays.java