You might want to look at pgBouncer to pool your drupal pgsql needs. I've found with 2000 needed connections, I can pool out to only 30 backends and still push 8k transactions per second.
I have a drupal site working with postgres that does not tolerate more than 200 concurrent connections(it is not hardware fault). Does anybody know how to adjust postgres parameters and what are them?, or how to get a better performance in any way?
