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From André Warnier ...@ice-sa.com>
Subject Re: 2 POST requests to underlying Server
Date Tue, 10 Aug 2010 12:33:39 GMT
Karthik Nanjangude wrote:
> Hi
> 
>>> Have you really traced the browser -> server side to see if the duplicate
POST request
> 
> As I have already said by using the TCP Thread dump using command
>   "tcpdump -i bond0 -s 1500 -w / tmp / test.pcap "
> 
> We are clearly able to see the IP Address of Apache written 2 times  POST for the JBOSS
( Tomcat built in) being called with in 12 seconds apart.
> 
> We also made sure there is no traffic /users using the web application during the tcp
dump taken.
> 
> 
>>> Are they really the same, from the same client, with the same content
> 
> For simple test case we used 1 simple transaction Page  to do the activity
> For insertion, but the since 2 request to web server ,we see 2 rows inserted in DB
> 
> This has happened in spite of blocking multiple button clicks on jsp page using jscript
filter.
> 
> 
>>> claim that Apache or mod_jk or Tomcat duplicates a POST
> 
> My Observation as per TCP dump command, we clearly see multiple request being sent from
Apache to web server.
> 
> 
Ok then, suppose that I believe you.
Then look at the following page :
http://tomcat.apache.org/connectors-doc/webserver_howto/apache.html
section : Logging

Use these mod_jk configuration instructions in Apache to set the mod_jk log level to 
"debug" and retry your test.
Then look at the mod_jk logfile, find the section(s) relevant to the two consecutive POST

requests, and see if you find a reason why mod_jk would send these two requests.
If it is as a result of an error, there should be error messages.
If you do not see the error, copy the the relevant lines here.
(really paste it, do not add it as attachment. This list generally strips them).
















> 
> 
> With regards
> KArthik
> 
> 
> 
> -----Original Message-----
> From: André Warnier [mailto:aw@ice-sa.com]
> Sent: Tuesday, August 10, 2010 4:48 PM
> To: Tomcat Users List
> Subject: Re: 2 POST requests to underlying Server
> 
> Karthik Nanjangude wrote:
>> Hi
>>
>>>> (*) do you have any particular reason to use this setting, instead of the
default ? Or is
>> it just something you copied from some blog page ?
>>
>>
>> 1) I have not copied the same from  any Blog , it is as defined
>>    configuration  as is from the N/w team
>>
>> 2) Where can I fine the default settings for the same ?
> 
> In the on-line documentation, at
> http://tomcat.apache.org/connectors-doc/reference/workers.html
> 
>>
>> 3) As I have already said We have put a Java script filter to disable
>>    multiple Clicks for dual request from the Browser ( IE 7+ / FF 3+ )
>>
> 
> Well, maybe it is not working.  Have you really traced the browser -> server side
to see
> if the duplicate POST request originates there ?
> 
> Plus, in your original message, you do not define very clearly what these 2 POST requests
> are.  Are they really the same, from the same client, with the same content ? how close
to
> one another do they arrive ?
> 
> If it was mod_jk resending the same request after the socket_timeout of 10 s, then the
2
> POST requests should be separated by at least 10 s.  Are they ?
> 
> As someone once said : Extraordinary claims require extraordinary proof.
> 
> In other words : you seem to claim that Apache or mod_jk or Tomcat duplicates a POST
> request.  This is not the behaviour experienced by the vast majority of Apache + mod_jk
+
> Tomcat installations.  So you need data a bit more solid than what you have supplied
so
> far, before someone will believe that there is another reason than the user clicking
twice.
> 
> 
> 
>>
>>
>>
>> With regards
>> karthik
>>
>>
>>
>> -----Original Message-----
>> From: André Warnier [mailto:aw@ice-sa.com]
>> Sent: Tuesday, August 10, 2010 4:10 PM
>> To: Tomcat Users List
>> Subject: Re: 2 POST requests to underlying Server
>>
>> Karthik Nanjangude wrote:
>>> Hi
>>>
>>> Spec
>>> Java 1.5
>>> O/s : Linux
>>> APP Server        :  JBOSS4.2.1 (Tomcat built with)
>>> HTTP Server      :  apache_2.2.11 [ With out SSL ]
>>> Mod library        :  mod_jk-1.2.28-httpd-2.2.X.so
>>> LB  1 Apache     :  1 JBOSS:Port of application
>>>
>>>
>>> Question :  Some times We have observed that  on WEB Application  ( click on
 button in jsp )
>>>                  Apache is sending 2 POST requests to underlying JBOSS ( Tomcat
server ).
>>>
>>> Note: We even put a Java script filter to disable multiple Clicks for the page,
>>>
>>>
>>> How we Observed :  Via TCP Thread dump using command    "tcpdump -i bond0 -s
1500 -w / tmp / test.pcap "
>>>
>>>
>>> Can this configuration "worker.node1.socket_timeout=10" got any thing to do with
this multiple request activity?
>>>
>> Unlikely, but :
>>
>> 1) simple test : remove this setting, and see if the issue still appears  (*)
>> (By removing the setting, you make the timeout infinite)
>>
>> 2) use the mod_jk logging level TRACE, to see exactly what mod_jk is sending to Tomcat
>>
>> 3) It is unlikely that any Apache or mod_jk or Tomcat component would repeat a POST
>> request, because that kind of violates the HTTP RFC.  So chances are, that the double
POST
>> request is /still/ coming from the browser.
>>
>>
>> (*) do you have any particular reason to use this setting, instead of the default
? Or is
>> it just something you copied from some blog page ?
>>
>>
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> 
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