Redmine

Folks--

We have a redmine system with a large number of issues (180,000~), custom fields (about 40; 30 or so searchable), and journal records (1.5M or so) and searching has become something of a slow process (It can take up to 30+ seconds). We recently upgraded the EC2 class for the instance that the system runs on and got only modest gains out of the change (which is sort-of what I was expecting).

I was wondering if anyone has any tips for speeding that up the search?