Fwd: AR + TinyTDS timeout fails to trigger on network failure

dubstep · July 28, 2011, 5:20pm

Hello Ruby and Rails developers.

Cross-posted to : Ruby-Talk, Rails-Talk, Jruby-Users

Could you all look into this Gist TinyTDS timeout on network failure of open connection · GitHub and
maybe
point out what I could be doing wrong in my network-failure test ?

The setup :
Mac OSX SnowLeopard
VirtualBox VM Guest of Windows 7 w/ SqlServer 2008R2 Express (default
server
instance)

The scenario :
osx (host) ruby script connects to guest sql instance and executes query
successfully
guest then receives power-failure (VM guest is “paused”)
osx (host) re-executes query on existing connection

Expected : Timeout in 5 sec on query
Got : TinyTDS DBPROCESS is dead or not enabled at 312 sec (varies on
300sec
+/- 20sec )

This block is repeatable (yes, blocks anyway) with the offending code
wrapped in Timeout.timeout and SystemTimer.timeout.
It also blocks in JRuby using Timeout.timeout.

The gist contains TinyTDS config with :timeout => 5000. I have also
tried
:timeout => 5 with above result.

I would greatly appreciate any advice you could give me on what may be
going
wrong here.

Thanks,
Peter F.

---------- Forwarded message ----------
From: Ken C. [email protected]
Date: Thu, Jul 28, 2011 at 6:40 AM
Subject: Re: [RailsSQLServer] AR + TinyTDS timeout fails to trigger on
network failure
To: [email protected]

Funny, it looks like you are basically rewriting this test?

github.com

rails-sqlserver/tiny_tds/blob/master/test/client_test.rb#L106


      
                assert_match %r{server name not found in configuration files}i, e.message, 'ignore if non-english test run'
              end
            end
            assert_new_connections_work
          end
          
          
it 'raises TinyTds exception with long query past :timeout option' do
            client = new_connection :timeout => 1
            action = lambda { client.execute("WaitFor Delay '00:00:02'").do }
            assert_raise_tinytds_error(action) do |e|
              assert_equal 20003, e.db_error_number
              assert_equal 6, e.severity
              assert_match %r{timed out}i, e.message, 'ignore if non-english test run'
            end
            assert_client_works(client)
            close_client(client)
            assert_new_connections_work
          end
          
          
it 'must not timeout per sql batch when not under transaction' do
            client = new_connection :timeout => 2

I tried running this the other day and could not get it to work.
FreeTDS’
DBLIB is a beast to get working right with lost connections and recover
the
DBPROCESS in such a way that it is still usable. One thing it does (that
I
hate) is that it tries doing some internal work to reconnect for you and
the
timeout setting appears to have a stepped curve. The end result is that
you
get double/triple the actual timeout if it works at all.

I can not remember if I just gave up after a few days of banging my head
on
the desk and decided to let the adapter cope with outright dead
connections
by dropping the ivar and re-establishing via standard ActiveRecord
conventions. Someone else putting their head into this would be
appreciated,
as I do not have the capacity any time soon. Patches patches!

Ken

churp · July 28, 2011, 8:29pm

Peter F. wrote in post #1013575:

Hello Ruby and Rails developers.

Cross-posted to : Ruby-Talk, Rails-Talk, Jruby-Users

http://www.catb.org/~esr/faqs/smart-questions.html#forum