If you turn on verbose gc for the JVM you could at least rule out GC pauses.
Hmm, exactly how do you route the requests through the apache server? It almost sounds like your applikation is restarted every now and then, iirc Apache only servers a limited amount of requests per server thread. If this somehow started a new JVM per apache thread things would go strange. What does $ps ax --forest say? /Linus Den 15 sep 2014 06:44 skrev "Shantanu Kumar" <kumar.shant...@gmail.com>: > Few thing to consider: > 1. Which API calls pause? If only certain calls pause, then probably you > have something specific to suspect. Try adding a dummy REST call - see if > that call pauses while others do. > 2. Is any of your services running on a t1.micro or a burst-oriented EC2 > instance on AWS? Try changing the instance type in that case. > 3. Can you mock out the components that you suspect could be a problem? > Begin by mocking out everything you suspect, then replace the mock with > actual impl one component at a time until you isolate the problematic > component. > 4. Have you tried running a profiler? > 5. Have you tried printing GC info? Maybe this could be useful: > http://blog.ragozin.info/2011/09/hotspot-jvm-garbage-collection-options.html > > Shantanu > > On Monday, 15 September 2014 09:45:14 UTC+5:30, larry google groups wrote: >> >> >> I have an embarrassing problem. I convinced my boss that I could use >> Clojure to build a RESTful API. I was successful in so far as that went, >> but now I face the issue that every once in a while, the program pauses, >> for a painfully long time -- sometimes 30 seconds, which causes some >> requests to the API to timeout. We are still in testing, so there is no >> real load on the app, just the frontenders, writing Javascript and making >> Ajax calls to the service. >> >> The service seems like a basic Clojure web app. I use Jetty as the >> webserver, and the libraries in use are: >> >> Ring >> >> Compojure >> >> Liberator >> >> Monger >> >> Timbre >> >> Lamina >> >> Dire >> >> When someone complains about the pauses, I will go test the service, and >> I can hit with 40 requests in 10 seconds and it has great performance. The >> pauses actually seem to come after periods of inactivity, which made me >> think that this had something to do with garbage collection, except that >> the pauses are so extreme -- like I said, sometimes as much as 30 seconds, >> causing requests to timeout. When the app does finally start to respond it >> again, it goes very fast, and responds to those pending request very fast. >> >> But I have to find a way to fix these pauses. >> >> Right now I packaged the app as an Uberjar and put it on the server, spun >> it up on port 24000 and proxied it through Apache. I put a script in >> /etc/init.d to start the app using start-stop-daemon. >> >> Possible things that could be going wrong: >> >> Maybe Jetty needs more threads, or maybe less threads? How would I test >> that? >> >> Maybe the link to MongoDB sometimes dies? (Mongo is on another server at >> Amazon) How would I test that? >> >> Maybe it is garbage collection? How would I test that? >> >> Maybe I have some code that somehow blocks the whole app? Seems unlikely >> but I'm trying to keep an open mind. >> >> Maybe the thread pool managed by Lamina sometimes gets overwhelmed? How >> would I test that? >> >> Maybe when Timbre writes to the log file it causes things to pause? (But >> I believe Timbre does this in its own thread?) How do I test that? >> >> This is a small app: only about 1,100 lines of code. >> >> I don't have much experience debugging problems on the JVM, so I welcome >> any suggestions. >> >> >> >> >> >> >> >> -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Clojure" group. 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