i, Could anybody comment on the postgres-pr driver, from performance point of view, is it faster than others?
I guess, a more appropriate place to check out for ruby/rails postgres drivers would be rubyforge.org itself. There is a libpq based postgres driver available there (ruby-postgres) but YMMV.
What other options are available to access postgresql in ruby/ruby on rails? which of them is most popular, better?
Again refer to rubyforge.org. There is a RubyES project amongst others. And lastly and more importantly I think this list is appropriate for Postgres database backend related performance questions only.