We now have 16-byte decimal values in Arrow which have been validated against the Java implementation. We need to be able to read and write these to Parquet format.
To make these values readable by Impala or some other Parquet readers may require some work. It expects the storage size to match the decimal precision exactly. So in parquet-cpp we will need to write the correct non-zero bytes into a FIXED_LEN_BYTE_ARRAY of the appropriate size.
We should validate this against Java Parquet implementations