presto-orc/src/main/java/io/prestosql/orc/reader/DecimalColumnReader.java/DecimalColumnReader/readLongNotNullBlock
class DecimalColumnReader:    private Block readLongNotNullBlock()
            throws IOException
    {
        verifyNotNull(decimalStream);
        verifyNotNull(scaleStream);

        long[] data = new long[nextBatchSize * 2];
        decimalStream.nextLongDecimal(data, nextBatchSize);

        for (int offset = 0; offset < data.length; offset += 2) {
            long sourceScale = scaleStream.next();
            if (sourceScale != type.getScale()) {
                Slice decimal = Slices.wrappedLongArray(data[offset], data[offset + 1]);
                UnscaledDecimal128Arithmetic.rescale(decimal, (int) (type.getScale() - sourceScale), Slices.wrappedLongArray(data, offset, 2));
            }
        }
        return new Int128ArrayBlock(nextBatchSize, Optional.empty(), data);
    }