tomcat-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Christopher Schultz <ch...@christopherschultz.net>
Subject Re: Packet misses in Tomcat
Date Thu, 09 Jan 2014 22:16:17 GMT
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

Divyaprakash,

On 1/8/14, 4:06 AM, Divyaprakash Y wrote:
> -----Original Message----- From: André Warnier
> [mailto:aw@ice-sa.com] Sent: 08 January 2014 02:52 To: Tomcat Users
> List Subject: Re: Packet misses in Tomcat
> 
> Christopher,
> 
> Christopher Schultz wrote:
>> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256
>> 
>> André,
>> 
>> On 1/7/14, 5:09 AM, André Warnier wrote:
>>> I do not pretend to know your system, nor your application, nor
>>> that the following is a definite explanation.  But on the base
>>> of the currently available data, I would say : - it is quite
>>> unlikely that Tomcat 7 is randomly "dropping requests". If it
>>> was, then I would imagine that this list would be overflowing
>>> with cries for help. There is quite a bit of traffic on this
>>> list related to Tomcat 7, but I don't recall seeing any
>>> significant number of issues mentioning "dropped requests". -
>>> it also doesn't seem, from your wireshark-related observations,
>>> that the requests are being lost outside of Tomcat. - so I
>>> would say at this point, that the most likely place for
>>> requests to disappear is in your own application.
>> 
>> It seems that Tomcat is not logging the request in its access
>> log, so it's more likely that the request is either malformed to
>> such an extent that Tomcat rejects the request altogether or that
>> the request never reaches Tomcat.
>> 
> ... Hi. Of course I am going essentially by what the OP provided
> earlier as information, and he has not provided much details on the
> "disappearing" requests themselves, or on the channel through which
> these requests were reaching Tomcat. But one thing that he did
> mention, is that these requests are similar - and even in general
> the same - as other requests which do get processed normally. As
> per his own words :
> 
> "For the query regarding "All requests", all requests do not
> disappear. More importantly, sometimes all requests  reach the
> application when I POST same set of requests. To give a rough
> picture, 1-2 requests fail in a set of 45-50 requests and this
> behaviour varies [The request which failed in my one test cycle
> succeeds in another cycle]."
> 
> If we take this at face value, then it should not be so that these
> requests are so malformed that Tomcat discards them without further
> ado. Also - but maybe I'm wrong there - I would expect, if Tomcat
> discards a request for being malformed - that something would
> appear in the Tomcat error log.  But according to the OP it
> doesn't. Finally - and there is a bit of an assumption on my part
> here - I assume that when the OP says that he sees the request with
> Wireshark (prior to it "disappearing" in Tomcat), he was running
> Wireshark on the Tomcat host itself.  That would make it unlikely
> that another external component is at play.
> 
> All of the above led me to suspect that something in the
> application itself may be playing a role here.
> 
> Of course, that all does not necessarily prove that some other
> component than Tomcat is not dropping some packets/requests.
>> 
> --
> 
> Clarifications for the missed information:

(I have re-ordered some of your responses so they make more logical
sense to me):

> - There are 2 machines (LAN) where client and servers are
> installed. Client is used to send the requests to Server. -
> Wireshark runs on the same machine where Tomcat runs - Tomcat will
> be accessed directly via HTTP

> - This issue occurs even if I use loopback address/localhost
> instead
of Server IP Address in the request URL (Install both client and
server in the same machine).

> - A war file with a servlet to POST the requests.

What is the client?

Is it possible that this is something simple like the TCP backlog
queue filling-up and the OS is just discarding requests?

- -chris
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
Comment: GPGTools - http://gpgtools.org
Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/
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=c+yc
-----END PGP SIGNATURE-----

---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org


Mime
View raw message