How do I go about enabling debug logging in Mongrel then?

There doesn't appear to be any mention of it in the docco. There is a post
on the mail list abour USR1 logging?



On 13 June 2012 19:39, Matt Hoyle <[email protected]> wrote:

> Hello,
>
> I've messing about with Plack::Handler::Mongrel2 plugged into a Dancer
> application and obviously Mongrel2.
>
> Under JMeter load testing hitting the same URL repeatedly I am getting
> into a situation where the front end requests start receiving a
>  "java.net.SocketTimeoutException: Read timed out" error. The tests are
> doing a repeated request "GET
> http://localhost:6767/app/polamaolaolaolaoaloalaoalaoalaoalaoalaoalaaoalaoaalaoalaoalaoa?j=8&t=1
> "
>
>
>
> Mongrel will always produce the following error for a failed request:
>
> [INFO] (src/mongrel2.c:343) Starting Mongrel2/1.7.5. Copyright (C) Zed A.
> Shaw. Licensed BSD.
> [INFO] (src/server.c:272) Starting server on port 6767
> [INFO] (src/task/fd.c:151) MAX limits.fdtask_stack=102400
> [INFO] (src/superpoll.c:102) Allowing for 256 hot and 768 idle file
> descriptors (dividend was 4)
> [INFO] (src/handler.c:209) MAX allowing limits.handler_targets=128
> [INFO] (src/handler.c:285) Binding handler PUSH socket tcp://
> 127.0.0.1:9998 with identity: E80576A8-AC0B-11DF-A841-3D4975AD5E34
> [INFO] (src/handler.c:311) Binding listener SUB socket tcp://
> 127.0.0.1:9999 subscribed to: D807E984-AC0B-11DF-979C-3C4975AD5E34
> [INFO] (src/control.c:401) Setting up control socket in at
> ipc://run/control
> *[ERROR] (src/register.c:214: errno: Resource temporarily unavailable)
> Nothing registered under id 0.*
> *[ERROR] (src/register.c:199: errno: None) Invalid FD given for exists
> check*
> *
> *
>
> Mongrel finish's the tcp connection to the http client after the zmq
> message is sent to the Plank back end:
>
> http client -> Mongrel 6767
> Mongrel -> plank 9998
> *This is when the problem occurs and client http connection is finished*
> Plank -> Mongrel 9999
> Mongrel -> Client 'high port'
>
>
> sudo tcpdump -n -i lo -s 158 -p tcp port 6767 or tcp port 9999 or tcp port
> 9998
>
> 18:11:11.991287 IP 127.0.0.1.52686 > 127.0.0.1.6767: Flags [P.], seq
> 30808:31037, ack 79381, win 384, options [nop,nop,TS val 41369964 ecr
> 41369963], length 229
> 18:11:11.991470 IP 127.0.0.1.9998 > 127.0.0.1.55744: Flags [P.], seq
> 17675:18211, ack 3, win 256, options [nop,nop,TS val 41369964 ecr
> 41369955], length 536
> 18:11:11.991480 IP 127.0.0.1.55744 > 127.0.0.1.9998: Flags [.], ack 18211,
> win 384, options [nop,nop,TS val 41369964 ecr 41369959], length 0
> 18:11:12.001689 IP 127.0.0.1.52686 > 127.0.0.1.6767: Flags *[F.]*, seq
> 31037, ack 79381, win 384, options [nop,nop,TS val 41369966 ecr 41369963],
> length 0
> 18:11:12.001759 IP 127.0.0.1.6767 > 127.0.0.1.52686: Flags *[F.]*, seq
> 79381, ack 31038, win 384, options [nop,nop,TS val 41369966 ecr 41369964],
> length 0
> 18:11:12.001772 IP 127.0.0.1.52686 > 127.0.0.1.6767: Flags [.], ack 79382,
> win 384, options [nop,nop,TS val 41369966 ecr 41369966], length 0
> 18:11:12.010615 IP 127.0.0.1.50171 > 127.0.0.1.9999: Flags [P.], seq
> 21123:21763, ack 3, win 257, options [nop,nop,TS val 41369968 ecr
> 41369956], length 640
> 18:11:12.010655 IP 127.0.0.1.9999 > 127.0.0.1.50171: Flags [.], ack 21763,
> win 384, options [nop,nop,TS val 41369968 ecr 41369960], length 0
>
>
> Whereas it normally looks like this:
>
> 18:11:11.968949 IP 127.0.0.1.52686 > 127.0.0.1.6767: Flags [P.], seq
> 29663:29892, ack 76441, win 384, options [nop,nop,TS val 41369958 ecr
> 41369958], length 229
> 18:11:11.969095 IP 127.0.0.1.9998 > 127.0.0.1.55742: Flags [P.], seq
> 17137:17673, ack 3, win 256, options [nop,nop,TS val 41369958 ecr
> 41369954], length 536
> 18:11:11.971890 IP 127.0.0.1.50169 > 127.0.0.1.9999: Flags [P.], seq
> 20483:21123, ack 3, win 257, options [nop,nop,TS val 41369959 ecr
> 41369955], length 640
> 18:11:11.972006 IP 127.0.0.1.6767 > 127.0.0.1.52686: Flags [P.], seq
> 76441:77029, ack 29892, win 384, options [nop,nop,TS val 41369959 ecr
> 41369958], length 588
> 18:11:11.973493 IP 127.0.0.1.52686 > 127.0.0.1.6767: Flags [P.], seq
> 29892:30121, ack 77029, win 384, options [nop,nop,TS val 41369959 ecr
> 41369959], length 229
>
>
> The only thing of note I found in Plack::Handler::Mongrel2 at the same
> time as the errors were undefined variable errors, but they were all
> related to the METHOD=JSON disconnect message being sent out after this
> issue has occured.
>
> I can increase the the frequency of the errors by increasing the debug
> logging on the Perl/Plack side of things so I believe it's something in the
> back end but I'm at a loss at the moment as to what could be causing it.
>  It happens with or without multiple threads or a single thread at each
> http client and plack levels.
>
> Any ideas on where to look next would be appreciated.
>
> Cheers,
> Matt
>
>

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