Jon Nelson <jnelson+pgsql@jamponi.net> writes:
> The most recent experiment shows me that, unless I create whatever
> indexes I would like to see used *before* the large (first) update,
> then they just don't get used. At all.
You're making a whole lot of assertions here that don't square with
usual experience. I think there is some detail about what you're
doing that affects the outcome, but since you haven't shown a concrete
example, it's pretty hard to guess what the critical detail is.
regards, tom lane
