Interesting problem. The application without the REST piece works OK -- and the REST piece works OK, but put them together and the whole thing slows down. That's my understanding of the problem.
I wonder if there's an issue in the middle -- is there a way to limit how many REST requests are in flight? If so, you might see how things go by limiting that number to see if you get better performance. Alternatively, is there some resource that a REST request uses in the application that's in short supply?
Alex / talexb / Toronto
Thanks PJ. We owe you so much. Groklaw -- RIP -- 2003 to 2013.