A columnar database is completely irrelevant to vector search. Vectors aren't stored in columns. Traditional indexing too is altogether irrelevant because brute force means a full pass through the data. Specialized indexes can be relevant, but then the search is generally approximate, not exact.
How's a database being columnar irrelevant to vector search? This very vector search extension shows that brute force search can work surprisingly well up to a certain dataset size and at this point columnar storage is great because it gives a perfect memory access pattern for the vector search instead of iterating over all the rows of a table and only accessing the vector of a row.
