-----Original Message----- From: Christopher Schultz [mailto:ch...@christopherschultz.net] Sent: 10 January 2014 03:46 To: Tomcat Users List Subject: Re: Packet misses in Tomcat
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Divyaprakash, On 1/8/14, 4:06 AM, Divyaprakash Y wrote: > -----Original Message----- From: André Warnier [mailto:a...@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? > Christopher, The client is nothing but a SOAP client which sends the SOAP packets at an interval of 30 seconds to the server. Looks like the situation of TCP backlog queue filling-up won't arise. FYI, the issue arises only when I use APR connector whereas default BIO connector works fine (both HTTP and HTTPS). I have not verified with NIO connector. Any pointer? ----------------------------------------------------------------------------------------------------------------------------- DISCLAIMER: This electronic message and any attachments to this electronic message is intended for the exclusive use of the addressee(s) named herein and may contain legally privileged and confidential information. It is the property of Celstream Systems Private Limited. 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