Florian Weimer <fweimer(at)bfk(dot)de> writes:
> -> Bitmap Index Scan on large_rel_1_field_1 (cost=0.00..2003.09 rows=193739 width=0) (actual time=0.148..0.148 rows=12 loops=1)
> Index Cond: (n.field_1 = "outer".field_2)
What you need to look into is why that rowcount estimate is off by four
orders of magnitude.
The estimate on the smaller table is only off by a factor of 75 but
that's still pretty darn awful. Are the statistics up to date? Maybe
larger stats targets would help.
regards, tom lane