I have never researched the timeline properly to understand at which point the concept/code got ditched, but it was part of Stonebraker's 1985 vision: https://dsf.berkeley.edu/papers/ERL-M85-95.pdf

> POSTQUEL allows users to save and query historical data and versions. By default, data in a relation is never deleted or updated. Conventional retrievals always access the current tuples in the relation. Historical data can be accessed by indicating the desired time when defining a tuple variable.

I looked this up during another thread which also has some other sources if you want to dig further: https://news.ycombinator.com/item?id=37956687

So pre-PostgreSQL then.

I would guess so, yes.

Thanks! I had used 6.0. I was totally unaware this was an option at the time. For what it was worth, Postgres was dog slow back then.