presto-raptor-legacy/src/main/java/io/prestosql/plugin/raptor/legacy/RaptorMetadata.java/RaptorMetadata/getDistributionInfo
class RaptorMetadata:    private DistributionInfo getDistributionInfo(long distributionId, Map<String, RaptorColumnHandle> columnHandleMap, Map<String, Object> properties)
    {
        Distribution distribution = dao.getDistribution(distributionId);
        if (distribution == null) {
            throw new PrestoException(RAPTOR_ERROR, "Distribution ID does not exist: " + distributionId);
        }
        List<RaptorColumnHandle> bucketColumnHandles = getBucketColumnHandles(getBucketColumns(properties), columnHandleMap);
        return new DistributionInfo(distributionId, distribution.getBucketCount(), bucketColumnHandles);
    }