Hi, I'm a questdb dev working on replication, we should have something working within a couple of months. If you have any questions feel free to ask me.
I'm a QuestDB dev, data on a QuestDb is also stored in a single address space and SQL queries are compiled into objects that run in that address space. However, it is just SQL not a bespoke language. A future possibility would be to allow queries in java or scala.
I'm a QuestDB dev, with regards to nano timestamps, we dont use a nanosecond timestamp because its not possible to be accurate to that resolution with current hardware. However, on a single host the nano second clocks are precise and monotonic, they would be useful to maintain order. I think they do make sense and we will have to look into providing timestamps to that resolution.