> >> I guess that in my case the improvement was more like 95%.
> >
> > I also saw a significant increase. ?The difference between my "fast"
> > machine and "slow" machine seemed to indicate that the difference was
> > primarily CPU related.
>
> That's consistent with it using a seq scan and having to sort the table.

It was performing indexed lookups for both versions of the query.  EXPLAIN 
showed that the only difference was the tableid filter(s). It sounds odd, but 
I'm fairly confident thats what I was seeing.  Unfortunately I didn't keep 
notes and can't be completely certain.

The index and static group size were definitely the big improvment, though.


> Oh, dear.
>
> Fortunately, you can deactivate that at runtime by setting the time
> it's trying to aim at to 0.

I misread the documentation, thanks for setting me straight.