mariusor , 
Hey #ActivityPub devs, what do you think about my SQL document storage table for ActivityPub objects?
https://github.com/go-ap/storage-sqlite/blob/master/init.go#L46
The dialect is SQLite, but Postgres supports all the features used here: virtual and generated columns, and json_extract.
I don't know about MySQL, but if someone can chime in about it, I'd love to hear from you.