Something tells me neither cursor nor openai need write workloads, so they would probably do just as fine using a flat file. I'm honestly curious what use either would have for queries that you couldn't get with a filesystem.
Certainly neither products have much obvious need for OLTP workloads. Hell, neither have any need for transactions at all. You're just paying them for raw CPU.
Update: in my mind, this reflects analytics of queries. Just further reason to run your own models I guess....
It's not just analytics. ChatGPT saves all of your conversation history - I don't know if they save the full conversation text in postgres, but I'd assume they at least save conversation metadata there.
You may not want this from a privacy perspective, but as a user I find it to be a very useful feature, e.g. I can see my full history, I can easily share conversations with a share link (and it's the exact version of that conversation, not like a URL where contents can change).