Use a columnar store for postgres instead of clickhouse#164

You may already have looked into this. But there are postgres extensions that implements columnar stores. One of these is the following -> https://pgxn.org/dist/cstore_fdw/ which is developed by the reputable Citus.

The reason for suggesting this in the first place is that I saw that there were some issues related to clickhouse -> https://github.com/plausible/analytics/issues/301

Thanks! Sorry but no plans to switch from Clickhouse. It is purpose-built for web analytics and it’s been proven at ridiculous scale at Yandex.Metrica. Column-based postgresql would have acceptable query performance but it wouldn’t replicate some features we rely on with Clickhouse e.g. CollapsingMergeTree table engine for real-time session analytics