db connection pool in Rails 2.3.x

Any idea how to set db connection "idle timeout" and "min. number of
connections" when configuring connection pool in Rails 2.3.x? These
settings are required since we want the db connection pool to warm up at
application/server startup. Required for a heavy usage website.

We are using JRuby and found one option in JRuby on Rails (uses J2EE
server's connection pooling config.) for doing this, but couldn't find
similar options in Ruby On Rails.