[janwas]

I don't know about "most", but here is a list: https://en.wikipedia.org/wiki/List_of_column-oriented_DBMSes

[ComputerGuru]

No, this is a list of columnar database systems - gp was saying the index, which is often (but not always) stored separately from the main db records.

[janwas]

Ah, indeed, my mistake. FWIW I've observed increasing numbers of papers over the past couple of years mentioning entirely columnar databases.