Re: poor performance involving a small table

>  Seq Scan on sensor  (cost=0.00..1.25 rows=1 width=6) (actual
> time=0.055..0.068 rows=1 loops=1)
>    Filter: (sensor_id = 12)
>  Total runtime: 801641.333 ms
> (3 rows)
>
> Can anybody help me out?  Thanks so much!

Does your table have millions of dead rows?  Do you vacuum once an hour?
  Run VACUUM FULL ANALYE sensor;

Chris