> Are the tables perhaps nearly in order by the dsiacctno fields?
> If that were the case, and the planner were missing it for some reason,
> these results would be plausible.
>
> BTW, what are you using for work_mem, and how does that compare to your
> available RAM?
>
> regards, tom lane
>
My assumption would be they are in exact order. The text file I used
in the COPY statement had them in order, so if COPY preserves that in
the database, then it is in order.
The system has 8GB of ram and work_mem is set to 256MB.
I'll see if I can't make time to run the sort-seqscan method so we can
have an exact time to work with.