Bryce Ewing <bryce(at)smx(dot)co(dot)nz> writes:
> So it seems to me that once the index is in memory everything is fine
> with the world, but the loading of the index into memory is horrendous.
So it would seem. What's the disk hardware on this machine?
It's possible that part of the problem is table bloat, leading to the
indexscan having to fetch many more pages than it would if the table
were more compact.
regards, tom lane