We take data integrity very seriously. This is one of the reasons QuestDB actually exists. We haven't had reports of data corruption or loss yet. We can commit durably if needed too.

To manipulate data we support "add" and "delete" column on the fly. We can also add column replace and type change if needed. This is pretty easy to do.

PostgreSQL wire is in beta. It works with JDBC driver and we will add metadata support quite soon.