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From André Warnier ...@ice-sa.com>
Subject Re: does this mod_jk.log look healthy?
Date Tue, 27 Jan 2009 21:33:03 GMT
Hi.

Sorry to invade/hijack, but I believe the following is very similar to 
the original OP's request.

Rainer, I have a case very similar to the one below at a customer, 
running under RHEL 5, with Apache 2.0.x, mod_jk 1.2.28 (dev) and Tomcat 
5.5.x. (the mod_jk 1.2.6 originally installed showed the same issues, 
only slightly different error messages).

I also have both kinds of messages, like the OP (from mod_jk to client, 
and from mod_jk to Tomcat).  What concerns me is the ones to the clients.
These messages happen very regularly (every few minutes), sometimes in 
bursts.  It is pretty-well established that the users do not click away 
from the page and do not click the "cancel" button.  The browser is IE6, 
and often returns a "This page cannot be displayed" ("friendly IE error 
message", which unfortunately cannot be turned off by the users, 
settings locked).
The users are getting pretty p.. off by what they perceive as an 
application problem, but we do not see a problem at the application 
level (logfiles etc..).
When users, after the IE error page, click the "reload" button, the same 
request/response usually works fine.
The users say that this problem affects only this application and/or 
server, but we do not know if they actually use any other comparable 
service.
The server is hosted by a service company, in a location physically 
distant from the users, but supposedly with good connectivity.
The server/application can sometimes take a while to respond to a 
request, but never more than say 10 seconds at most, and users kind of 
know when they ask a heavy question, so they would not really get so 
impatient.
Users are spread out, so even when monitoring the mod_jk log in real 
time it is not easy to immediately connect one of these client-side 
mod_jk error messages with the occurrence of an error at IE level.  We 
just kind of suppose they are linked.
The problem is specific to that customer site. We have similar setups at 
many other places, none of them exhibiting the same issue.

Any ideas/suggestions of what we could do to better pin-point the 
problem ? (or of some setting to overcome it ?)

Note that I am not saying that mod_jk has any responsibility in the 
issue.  It is just that the mod_jk log seems to be the only one that 
actually sems to show where the error happens.

Thanks.

Rainer Jung wrote:
> Hi,
> 
> On 27.01.2009 13:20, Arne Riecken wrote:
>> Hi,
>>
>> please have a look at the mod_jk.log. Can anyone say if these info-entrys
>> are normal or if the system is unhealthy? Or might the network be bad? 
>> These
>> entrys come at least two times per hour.
> 
> 1) All messages are info level, that's good.
> 
> 2) All messages with the same process id and thread id (the number pair 
> following the timestamp) and close to each other in time belong to the 
> same event.
> 
> 3) In you log excerpt, there are two types of events:
> 
> a) client abort
> 
> ajp_process_callback::jk_ajp_common.c (1448): Writing to client aborted 
> or client network problems
> 
> ajp_service::jk_ajp_common.c (1857): (worker6) request failed, because 
> of client write error without recovery in send loop attempt=0
> 
> service::jk_lb_worker.c (1068): unrecoverable error 200, request failed. 
> Client failed in the middle of request, we can't recover to another 
> instance.
> 
> jk_handler::mod_jk.c (2158): Aborting connection for worker=routerExt2
> 
> Client write error means, that when sending back data to the browser, 
> the web server realized that the browser already closed the connection. 
> Most likely the user decided to click on some link while waiting for a 
> response. If this happens only occasionally, it should be fine. If it 
> happens very often it might be an indication for performance problems, 
> i.e. your users clicking repeatedly on the same links, because they 
> don't get a fast answer.
> 
> b) idle connection timeouts
> 
> ajp_send_request::jk_ajp_common.c (1215): (worker1) error sending 
> request. Will try another pooled connection
> ajp_send_request::jk_ajp_common.c (1241): (worker1) all endpoints are 
> disconnected
> ajp_send_request::jk_ajp_common.c (1244): (worker1) increase the backend 
> idle connection timeout or the connection_pool_minsize
> ajp_service::jk_ajp_common.c (1941): (worker1) sending request to tomcat 
> failed,  recoverable operation attempt=1
> 
> Without additional error level messages that's OK. The web server 
> noticed, that there was no connection to the backend open and will 
> transparently create a new one. This could happen, if your web server is 
> more idle than configured with the JK connection pool timeout or 
> Tomcat's connectionTimeout.
> 
> 4) Please keep info log level. As long as there are no warn or error 
> messages, everything is fine, but once there are error messages, the 
> aditional info messages are helpful.
> 
> You should update to 1.2.27, it's better than 1.2.23 :)
> 
> Regards,
> 
> Rainer
> 
> 
>> Thanks.
>>
>> mod_jk 1.2.23
>> Apache 1.3.34
>> Tomcat 5.5.20
>>
>> socket_keepalive=False
>> connect_timeout=30000
>> prepost_timeout=30000
>> connection_pool_timeout=600
>>
>> all others default
>>
>> Firewall is dropping idle connections after 1h.
>>
>> [Sat Jan 24 01:07:15 2009] [29654:0000] [info]
>> ajp_process_callback::jk_ajp_common.c (1448): Writing to client ab
>> orted or client network problems
>> [Sat Jan 24 01:07:15 2009] [29654:0000] [info]  
>> ajp_service::jk_ajp_common.c
>> (1857): (worker6) request failed, because of client write error without
>> recovery in send loop attempt=0
>> [Sat Jan 24 01:07:15 2009] [29654:0000] [info]  service::jk_lb_worker.c
>> (1068): unrecoverable error 200, request failed. Client failed in the 
>> middle
>> of request, we can't recover to another instance.
>> [Sat Jan 24 01:07:15 2009] [29654:0000] [info]  jk_handler::mod_jk.c 
>> (2158):
>> Aborting connection for worker=routerExt2
>> [Sat Jan 24 01:08:53 2009] [31110:0000] [info]
>> ajp_send_request::jk_ajp_common.c (1215): (worker1) error sending 
>> request.
>> Will try another pooled connection
>> [Sat Jan 24 01:08:53 2009] [31110:0000] [info]
>> ajp_send_request::jk_ajp_common.c (1241): (worker1) all endpoints are
>> disconnected
>> [Sat Jan 24 01:08:53 2009] [31110:0000] [info]
>> ajp_send_request::jk_ajp_common.c (1244): (worker1) increase the backend
>> idle connection timeout or the connection_pool_minsize
>> [Sat Jan 24 01:08:53 2009] [31110:0000] [info]  
>> ajp_service::jk_ajp_common.c
>> (1941): (worker1) sending request to tomcat failed,  recoverable 
>> operation
>> attempt=1
>> [Sat Jan 24 01:14:46 2009] [31781:0000] [info]
>> ajp_send_request::jk_ajp_common.c (1215): (worker1) error sending 
>> request.
>> Will try another pooled connection
>> [Sat Jan 24 01:14:46 2009] [31781:0000] [info]
>> ajp_send_request::jk_ajp_common.c (1241): (worker1) all endpoints are
>> disconnected
>> [Sat Jan 24 01:14:46 2009] [31781:0000] [info]
>> ajp_send_request::jk_ajp_common.c (1244): (worker1) increase the backend
>> idle connection timeout or the connection_pool_minsize
>> [Sat Jan 24 01:14:46 2009] [31781:0000] [info]  
>> ajp_service::jk_ajp_common.c
>> (1941): (worker1) sending request to tomcat failed,  recoverable 
>> operation
>> attempt=1
>> [Sat Jan 24 01:15:04 2009] [31959:0000] [info]
>> ajp_send_request::jk_ajp_common.c (1215): (worker9) error sending 
>> request.
>> Will try another pooled connection
>> [Sat Jan 24 01:15:04 2009] [31959:0000] [info]
>> ajp_send_request::jk_ajp_common.c (1241): (worker9) all endpoints
>> are disconnected
>> [Sat Jan 24 01:15:04 2009] [31959:0000] [info]
>> ajp_send_request::jk_ajp_common.c (1244): (worker9) increase the backend
>> idle connection timeout or the connection_pool_minsize
>> [Sat Jan 24 01:15:04 2009] [31959:0000] [info]  
>> ajp_service::jk_ajp_common.c
>> (1941): (worker9) sending request to tomcat failed,  recoverable 
>> operation
>> attempt=1
>> [Sat Jan 24 01:20:49 2009] [31828:0000] [info]
>> ajp_process_callback::jk_ajp_common.c (1448): Writing to client ab
>> orted or client network problems
>> [Sat Jan 24 01:20:49 2009] [31828:0000] [info]  
>> ajp_service::jk_ajp_common.c
>> (1857): (worker9) request failed, because of client write error without
>> recovery in send loop attempt=0
>> [Sat Jan 24 01:20:49 2009] [31828:0000] [info]  service::jk_lb_worker.c
>> (1068): unrecoverable error 200, request failed. Client failed in the 
>> middle
>> of request, we can't recover to another instance.
>> [Sat Jan 24 01:20:49 2009] [31828:0000] [info]  jk_handler::mod_jk.c 
>> (2158):
>> Aborting connection for worker=routerExt3
>> [Sat Jan 24 01:20:54 2009] [22380:0000] [info]
>> ajp_process_callback::jk_ajp_common.c (1448): Writing to client ab
>> orted or client network problems
>> [Sat Jan 24 01:20:54 2009] [22380:0000] [info]  
>> ajp_service::jk_ajp_common.c
>> (1857): (worker9) request failed, because of client write error without
>> recovery in send loop attempt=0
> 
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