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From "Jorge Medina" <>
Subject RE: Problem with mod_jk and Tomcat Native Connectors on Solaris
Date Fri, 06 Feb 2009 17:00:42 GMT
Hallo Rainer!
  Danke für dein Hilfe. 
  I will follow your recommendation on upgrading, and I will need to learn how to configure
a more verbose log and interpret them.

  I found out the following:

	- My client code (a java Axis2 client) had a timeout (I found it was 30 sec, I was under
the assumption the default was 60s). When the client timeoust I would get a message "Read
timed out" 
	- The above timeout was too short, the client would timeout before Apache (mod_jk) had a
chance to retry the request to Tomcat. 

   I played with both timeouts, making sure the client timeout was always larger than the
mod_jk reply_timeout for at least a factor of 2. 
   This works pefectly in RedHat, but not in Solaris 10 (I tried sparc and x86, both compiled
in 64-bit)

   In Solaris, I think the Tomcat Native library just loses some requests. No matter how I
configured the timeouts and retries, I always get some sporadic "504 Gateway timeout". Disabling
the Tomcat Native library and keeping everything in mod_jk the same works fine. So, for now
I just disabled the Tomcat Native Library. 

   Thanks again for your response.


-----Original Message-----
From: Rainer Jung [] 
Sent: Friday, February 06, 2009 11:38 AM
To: Tomcat Users List
Subject: Re: Problem with mod_jk and Tomcat Native Connectors on Solaris

On 02.02.2009 20:01, Jorge Medina wrote:
>    I am having problems with the mod_jk module 1.2.26 and Tomcat 
> Native connectors running in Solaris 10.
>    The problem occurs in both processors x86 (64-bit) and sparc (64-bit).
> (The problem does not occur on RedHat EL5 64-bit).
>    On the mod_jk file I am specifying a value for
> reply_timeout:
>      worker.localworker.reply_timeout=10000    (10 seconds)
>    I am anticipating that some requests would need more time, so I 
> decided to run my test suite just increasing the value to 30000.
>    Oddly, with this value and running the same set of tests I get 
> sporadic errors. The mod_jk log shows the following message when this
> occurs:
>     [error] ajp_get_reply::jk_ajp_common.c (1730) : (localworker) 
> Timeout with waiting reply from tomcat. Tomcat is down, stopped or 
> nertwork problems (errno=145)
>     I am using the following components:
>          Apache Web Server 2.2.11
>                  APR 1.3.3
>                  APR-util 1.3.4
>                  openssl-0.9.8
>                  mod_jk    1.2.26

Before debugging a problem you might consider switching to 1.2.27, because once everything
works, you'll most likely not do the upgrade ;)

>          Tomcat 6.0.16
>                  Tomcat Native Connectors 1.1.12 (using same APR 
> version as Apache)

Please update to 1.1.16. There have been a couple of fixes in tcnative.

>                  jsvc
>                  Sun Java JDK 1.6
>      I also found that the problem only occurs if the Tomcat Native 
> Connectors is enabled in Tomcat.
>      I can't figure why increasing the reply timeout would actually 
> produce the errors it is supposed to prevent!!

I don't really understand: why do you think the timeout produces the problem? Setting the
timeout means, that any reply taking longer than the timeout will be interrupted inside Apache
and logged. So setting no timeout will not produce any log statements (by default the timeout
is off), but I expect that you will still have long running requests.

To find out about the response times and the requests with long response times, add "%D" to
your Apache LogFormat (response times in
microseconds) and activate an access log in tomcat too, with a pattern that also contains
"%D" 8response times in milliseconds). That way you can control during your tests, what tomcat
resp. Apache think the response time actually was.

After verifying that Tomcat actually needs to long for some requests, you need to start to
analse why (locking in application, waiting for backend or database, etc.). You can use Java
thread dumps for this (kill -QUIT).

>      Any help is appreciated. I would like to benefit from the Tomcat 
> Native Connectors, but I can't figure what I am configuring wrong.

Try 1.1.16.

>      -----------------------------------------------
>      Below is my ...
>      -----------------------------------------------
> worker.list= wlb, jkwatch, jkmanage
> # Properties for worker: localworker
> worker.localworker.type=ajp13
> worker.localworker.port=8009
> worker.localworker.lbfactor=1
> worker.localworker.connection_pool_timeout=600
> worker.localworker.socket_keepalive=True
> worker.localworker.socket_timeout=60
> ################### this parameter causes trouble if increased to 
> 30000 worker.localworker.reply_timeout=10000
> #################################
> # Defining a load balancer (with a single worker, the local worker) 
> worker.wlb.type=lb worker.wlb.balance_workers=localworker
> worker.wlb.max_reply_timeouts=3

I would add cping/cpong. See

> -----------------------------------------------
>    ... and here is the segment of server.xml
> -----------------------------------------------
>   <Connector port="8009"
>                 protocol="AJP/1.3"
>                 connectionTimeout="600000"
>                 enableLookups="false"
>                 bufferSize="32768"
>                 maxThreads="3000"/>
> - Jorge

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