> Ok, so ...evenly distributed data on small set of values forces
> sequential scan since that's faster. I expected that based on
> what I've read so far.
Actually, it's more a case of that fetching an item via and index is
considered, say, four times slower than fetching something off a
sequential scan (sort of). Hence, if you are selecting more than 25% of
the table, then a sequential scan will be faster, even though it has to
process more rows.
Chris