[dgudkov]

SQL calculations on columnar data are quite different from row-based databases, so its effectively a different database engine. You can take multiple advantages of columnar data store, because it usually employs a form of vocabulary compression. For instance, obtaining distinct values of a field in a columnar DB is much faster because it's typically just the vocabulary of the field, so it doesn't even require a full table scan. Many other columnar computations such as filtering or aggregation can be done on compressed data without decompression.