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From "Vadheraju, Rajeshwar" <Rajeshwar.Vadher...@fisglobal.com>
Subject RE: Stale Connection Check
Date Wed, 30 Mar 2011 21:17:53 GMT
Thanks, Oleg.
If I implement "retry", It may resolve #1 of 3 issues that I have.
Again, I was running into
1) Connection Reset - Client is trying write/send a request, connection broken - "retry" perfectly
work
2) Broken Pipe - Client is trying to read the response from server, connection broken. In
this situation, If I "retry", I see HttpClient retries entire request, which could cause server
to receive duplicate requests, which is not desirable.
3) Server failed to respond error - NoHttpResponseException - I think it is similar to #2
above.

-----Original Message-----
From: Oleg Kalnichevski [mailto:olegk@apache.org] 
Sent: Wednesday, March 30, 2011 9:10 AM
To: HttpClient User Discussion
Subject: RE: Stale Connection Check

On Tue, 2011-03-29 at 23:11 -0500, Vadheraju, Rajeshwar wrote:
> Oleg, Thanks for your response.
> We can't upgrade to 4.1 in a day or two as the mentioned errors are occurring in Production
environment. We will consider moving to 4.x in near future(may be in the next release), thanks
for your suggestion.
> 
> I went through link that you provided , In "2.10. Connection eviction policy", it reads
like "...The stale connection check is not 100% reliable..."
> 
> So my question is why stale connection check is not reliable, doesn't matter whether
it is version 3.1 or 4.x? 
> 

HTTP connection can be closed by either endpoint and become 'stale' on
the opposite end at any given moment. There is always a window, albeit
small, between a successfully completed stale connection check and
flushing of the internal session buffer containing the outgoing request
message, in which the underlying connection can become stale without
Httpclient's noticing until it is too late.

I would go as far as saying that the stale connection check is useless
and evil. It by no means can be used as a substitute for a sensible
request retry / recovery mechanism. 

Hope this helps

Oleg


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