Thanks, I've updated the post. I was unclear in what behavior we saw. The issue isn't that truncate isn't O(1), but that work that occurs after truncate has wi

Thanks, I've updated the post. I was unclear in what behavior we saw. The issue isn't that truncate isn't O(1), but that work that occurs after truncate has wildly inconsistent behavior in time (i.e. you see the same query on the same dataset take 10x the time). To me, that suggests that either Postgres is doing some work in the background, which hits at a random time, or that some query that is expecting statistics to have updated.