How long will the query take

I ran a query out of pgAdmin, and (as I expected) it took a long
time. In fact, I did not let it finish. I stopped it after a little
over an hour.

I'm using 8.4.2 on a Mac with a 2.4GHz processor and 2GB of RAM.

My question is: is there a way to tell how close the query is to being
finished. It would be a great pity if the query would have finished
in the 10 seconds after I quit it, but I had no way of telling.

As a postscript, I would add that the query was undoubtedly too
ambitious. I have a reduced set version which I will run shortly.
But I am still curious to know if there is a way to tell how much time
is left.

Thanks,

John