[#JRUBY-2307] DRb from MRI server to JRuby client fails with long messages

JRuby

DRb from MRI server to JRuby client fails with long messages

Created: 20/Mar/08 06:05 PM Updated: 20/Mar/08 06:59 PM

Component/s:

Core Classes/Modules

Affects Version/s:

JRuby 1.1RC2

Fix Version/s:

None

Time Tracking:

Not Specified

Environment:

Mac OS X 10.4, JRuby 1.1RC2, Ruby 1.8.6

Description

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DRb Server

require 'drb'
class TestServer
  def get_string(size)
    "1" * size
  end
end
server = TestServer.new
DRb.start_service('druby://localhost:12345', server)
DRb.thread.join

DRb Client

require 'drb'
obj = DRbObject.new(nil, 'druby://localhost:12345')
[1007, 1008].each do |n|
  begin
    obj.get_string(n)
    puts "Worked with size #{n}"
  rescue Exception => e
    puts "Exception with size #{n}: #{e.inspect}"
  end
end

		SERVER
		MRI	JRuby
CLIENT	MRI	works	works
	JRuby	breaks at 1008	works

Both 1007 and 1008 work fine in unless the server is running in MRI and the client is running in JRuby. In that case, sending a string of 1008 characters causes this exception on the JRuby client:
DRb::DRbConnError: premature marshal format(can't read)
from /usr/local/jruby/lib/ruby/1.8/drb/drb.rb:580:in `load'
from /usr/local/jruby/lib/ruby/1.8/drb/drb.rb:633:in `recv_reply'
from /usr/local/jruby/lib/ruby/1.8/drb/drb.rb:921:in `recv_reply'
from /usr/local/jruby/lib/ruby/1.8/drb/drb.rb:1195:in `send_message'
from /usr/local/jruby/lib/ruby/1.8/drb/drb.rb:1086:in `method_missing'
from /usr/local/jruby/lib/ruby/1.8/drb/drb.rb:1085:in `open'
from /usr/local/jruby/lib/ruby/1.8/drb/drb.rb:1159:in `method_missing'
from /usr/local/jruby/lib/ruby/1.8/drb/drb.rb:1085:in `with_friend'
from /usr/local/jruby/lib/ruby/1.8/drb/drb.rb:1084:in `method_missing'
from /usr/local/jruby/lib/ruby/1.8/drb/drb.rb:1085:in `puts'

This example is much simplified from my original problem which involved sending other objects. It seems that the problem is related to the size of the marshalled data, not what the data is. One thing to note though is that occasionally sending 1008 characters will work just fine. This is a small percentage of the time but it does happen.

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Sean Carr - 20/Mar/08 06:29 PM

still an issue in JRuby 1.1RC3

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Sean Carr - 20/Mar/08 06:59 PM

These numbers only seem to apply when running the client in jirb. When running the client via command line with jruby the tipping point seems to be much higher and even so the exception is less frequent. The bigger it gets the more frequent the error. At 10k it happened only a couple percent of the time but at 100k it happens a majority of the time.