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From David Cleary <>
Subject RE: 21 second pause that randomly happens
Date Fri, 20 Jul 2018 13:29:12 GMT
Thanks for the feedback. I was confident all along this wasn't a Tomcat issue, and I believe
we identified the culprit as the firewall. I was looking for logging that would show the socket
behavior (accept, close, etc.) to show that as far as Tomcat was concerned, the delay was
happening before it got there. Anyways, we were able to do some testing without the particular
firewall they were using and the results were encouraging. Will be a few days of testing before
they try it on their production system to confirm it, but so far, so good.


-----Original Message-----
From: charlie arehart [] 
Sent: Thursday, July 19, 2018 12:24 PM
To: 'Tomcat Users List' <>
Subject: RE: 21 second pause that randomly happens

David? Are you still needing help with this? Your answers to what I ask may help us get you
to a solution.


-----Original Message-----
From: charlie arehart <> 
Sent: Tuesday, July 17, 2018 01:14 PM
To: 'Tomcat Users List' <>
Subject: RE: 21 second pause that randomly happens

Going back to David's original note, you wrote, " We have a customer who is experiencing a
random, 21 second pause when using out Tomcat based application server. We believe this may
be during a TCP connect and timeout. Logging indicates the pause happens before the request
makes it to our back end."

Can you clarify what you mean by the "back end" here? 

Since you say it's a pause "when using" Tomcat, I can't tell if you're saying Tomcat IS the
backend, or instead if the request hangs WHILE running in Tomcat but doesn't reach some other
"backend" that the Tomcat-based app should then talk to. You did refer in a later note to
a "backend agent log", so I'm inclined to think it's the latter.

In that case, it seems you are wondering (in one note) whether the request might be hung up
in the connector (getting TO Tomcat). 

But do you know for sure whether the request is actually running IN Tomcat? You could use
any of various JVM or Tomcat monitoring tools to know a) if the request reaches Tomcat, b)
if it is hanging while running there, and then c) just WHAT the request is hanging and waiting
for (which could well be that "other backend" the app needs to talk to). 

But before elaborating on approaches, I wanted to ask what you may or may not know in regard
to the above, first. :-)


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