presto-main/src/main/java/io/prestosql/operator/PartitionedLookupSource.java/PartitionedLookupSource/encodePartitionedJoinPosition
class PartitionedLookupSource:    private long encodePartitionedJoinPosition(int partition, int joinPosition)
    {
        return (((long) joinPosition) << shiftSize) | (partition);
    }