code: public final long getTimestampAsLong(int columnIndex) {
          validateColumnType(columnIndex, VoltType.TIMESTAMP);
          final long value = m_buffer.getLong(getOffset(columnIndex));
          m_wasNull = (value == Long.MIN_VALUE); // see value.h
          return value;
      }
docs: Retrieve the <tt>long</tt> timestamp stored in the column specified by index.
  Note that VoltDB uses GMT universally within its process space. Date objects sent over
  the wire from clients may seem to be different times because of this, but it is just
  a time zone offset. Timestamps represent microseconds from epoch.
  @param columnIndex Index of the column
  @return <tt>long</tt> timestamp value stored in the specified column
  @see #wasNull()
  @see #getTimestampAsTimestamp(int)