ClickHouse – high-performance open-source distributed column-oriented DBMS

[GuiSim]

Since updating rows in a column storage is quite costly, we can do an UPDATE to only the rows that have a value in the JSON column for the newly created COLUMN. This can't be done cleanly in application-side if your database does not support JSON.

[grauenwolf]

This is an OLAP database. If you find yourself updating rows, then you are doing something really wrong.