Instead of restarting the database try swapoff -a && swapon -a and see if that helps performance. If it is that little swap in use, it might be something else clogging up the works.Yes, a few hundred MB of swap, and its definitely making a huge difference. Upon restarting postgres, its all freed up, and then perf is good again. Also, this box only has 1GB of swap total, so its never going to get up a few dozen GB. Anyway, here's some of top output for systemA right now: