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The one problem with using Clojure on App Engine is that the time for a "loading request" is at least 5 seconds. It makes your app look bad for the random user stuck on the loading request.

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I'll interpret that as a dig against the App Engine and not Clojure... even though it's clearly aimed at either Clojure alone or the combination with GAE.

Anyway, are you being serious (i.e., in your experience is clj+gae noticeably slower than java+gae or python+gae?) or just funny? Since I've never done any serious profiling of Clojure on GAE, I'll bite and do some brief performance tests and report back.

I am serious when I say that the GAE loading request time for a Clojure app is noticeably longer than the time for Java or Python. I searched for some benchmarks and found this: http://github.com/garyburd/app-eng-cold-start-test See http://googleappengine.blogspot.com/2009/12/request-performa... for more info on loading request perf.

Both of those are about "loading requests" which happen pretty rarely in the larger scheme of things (on upload, new server for app, too much traffic so need to scale jvm). On my current project, it's 3.5-4 seconds. Definitely not ideal, but it's not that common an event.

I'd like to run some benchmarks for normal requests, where I doubt there'll be any real difference.

Thanks for the search.

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