I think a columnar database can be super useful. I use Postgres a lot, but with a largish database, I managed to get the whole database footprint in Clickhouse

I think a columnar database can be super useful. I use Postgres a lot, but with a largish database, I managed to get the whole database footprint in Clickhouse smaller than the primary key index in Postgresql. (~80GB vs 160GB, and 1.2 TB for the whole unencrypted PG database) Now, it wasn't a great index key and the original schema wasn't good, but optimizing PG got me about a factor of 3 or 4, and Clickhouse compression got me another order of magnitude.