[jruby-user] Re: Super-simple DRb server hangs in JRuby (but not in C Ruby) when hit with multiple simultaneous requests

Sorry, I should've been more specific about the test scenario: this
was on a Mac running Leopard, using JRuby 1.0.2.

-- Scott

On Nov 19, 2007 4:21 PM, Scott Davies <scottd@xxxxxxxxx> wrote:
> Hi --
>
> I just tried writing a Lucene indexserver running in DRb under JRuby,
> and immediately ran into a problem where the server would very quickly
> hang if I tried to throw requests at it from more than one client
> simultaneously.  So, I yanked out all the Lucene stuff to diagnose the
> problem, and sure enough, the problem has nothing to do with Lucene
> and everything to do with JRuby and DRb.  Here's the test code in its
> entirety:
>
> ------------------------------------------------
> # test_server
> #!/usr/bin/env jruby
> require 'drb'
>
> class PingPong
>   def ping
>     "pong"
>   end
> end
>
> DRb.start_service("druby://127.0.0.1:4323", PingPong.new)
> DRb.thread.join
> -------------------------------------------------
> # test_client
> #!/usr/bin/env jruby
> require 'drb'
>
> pingpong = DRbObject.new(nil, "druby://127.0.0.1:4323")
>
> i = 0
> while true
>   i = i+1
>   pong = pingpong.ping
>   puts pong + " " + i.inspect
> end
> --------------------------------------------------
>
> Everything works OK if I start one test_server process and then one
> test_client process.  When I start up a second simultaneous
> test_client process, though, within a few requests everything comes to
> a screeching halt: the server fails to respond to any further
> requests.  (Killing the clients and starting another doesn't help: the
> server's still locked up.)
>
> If I use C Ruby for the server instead of JRuby, though, then
> everything works fine.
>
> Am I missing something?  Is there a workaround for this problem?  Or
> is JRuby almost entirely useless for DRb? :-(
>
> Thanks,
>
> -- Scott
>

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