... btw, I now see that tern and hornet are passing this test at least as much as they're failing, proving that there's some timing or random chance involved. That doesn't completely eliminate the idea that there may be an architecture component to the issue, but it sure reduces its credibility. I now believe the theory that the triggering condition is an auto-analyze happening at the right time, and populating pg_statistic with some data that other runs don't see.
regards, tom lane
