@Override
    public UTF8String getString(int colId) {
        int offset = colId == 0 ? 0 : sums[colId - 1];
        int to = sums[colId];
        return UTF8String.fromBytes(data.array(), offset, to - offset);
    }
A simple row can only store simple values like int, double, string. But cannot store multi-value column.
indexr-segment/src/main/java/io/indexr/segment/helper/SimpleRow.java