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From ilya goberman <gober...@msn.com>
Subject RE: How to disable chunked encoding for the Http11NioProtocol connector.
Date Wed, 05 Jan 2011 17:43:28 GMT

Mark, 
1) TCP/IP overhad? Not sure why you got this involved. It applies for both chunked and "normal"
encoding. Certainly, TCP/IP packets can span across multiple chunks or one chunk can be split
into multiple packets. Or maybe you are implying that chunked encoding will generate more
packets and increase bandwidth even furhter? This is probably true. 
2) I am astonished myself, but it is the fact. An example is Android browser: http://code.google.com/p/android/issues/detail?id=13044
3) I already requested an enhancement and you rejected it.
Thanks

> Date: Wed, 5 Jan 2011 16:38:20 +0000
> From: markt@apache.org
> To: users@tomcat.apache.org
> Subject: Re: How to disable chunked encoding for the Http11NioProtocol connector.
> 
> On 05/01/2011 15:29, ilya goberman wrote:
> > 
> > Mark, overhead of chunked encoding can be significant. My typical message is about
50 bytes and chunked encoding takes 6 bytes per message: about 12%. I use JSON protocol that
is already compressed (the way JSON can be compressed).
> 
> You are ignoring the TCP/IP overhead. That is around 40 bytes per
> packet. More if you take account of the ACK.
> 
> > Using  "Connection: close" with "Content-Length" header omitted is perfectly valid
from HTTP perspective. The end of response is detected by terminating connection on the server
side. 
> 
> I am well aware of that. I am also well aware that a client that
> declares itself HTTP 1.1 capable must support chunked encoding. I am
> frankly astonished that a client is so broken it can't handle chunked
> encoding.
> 
> > In fact some browsers have problems detecting connection termination (and host of
other issues) related to the chunked encoding.
> 
> Which browsers?
> 
> > While I understand it is not a Tomcat issue, it will score some points for Tomcat
if this is addressed by adding a configuration option.
> 
> Sure, feel free to request an enhancement to optionally restore the
> non-chunked approach when keep-alive is disabled. I'm not sure how much
> interest there will be in implementing it though.
> 
> Mark
> 
> > Thanks
> > 
> >> Date: Wed, 5 Jan 2011 06:14:18 +0000
> >> From: markt@apache.org
> >> To: users@tomcat.apache.org
> >> Subject: Re: How to disable chunked encoding for the Http11NioProtocol connector.
> >>
> >> On 05/01/2011 05:04, ilya goberman wrote:
> >>>
> >>> Hi,
> >>> I use NIO HTTP Tomcat connector org.apache.coyote.Http11NioProtocol to implement
Comet streaming to browsers and mobile devices.
> >>>
> >>> I would like to disable HTTP response chunked encoding to reduce bandwidth.
> >>
> >> How significant is the overhead with chunking in your case? I'd expect
> >> it to be pretty small unless only a few bytes are sent at a time (and
> >> even then there is the overhead for the packet).
> >>
> >> Is there any mileage in using compression to reduce bandwidth instead?
> >> Issues with flushing compressed output streams [1] were fixed last year.
> >>
> >>> The response will have header "Connection: close" with "Content-Length"
header omitted.
> >>> Is there a way to do it besides having client send HTTP 1.0 request (that
is not possible in the majority of cases)?
> >>
> >> Having looked at the relevant source code the only two ways I can see are:
> >> - sending an HTTP 1.0 request
> >> - declaring a content length
> >>
> >> It used to be possible to control this by disabling keep-alive but that
> >> was changed back in April last year [2],[3] as a result a discussion on
> >> the dev list [4]. If your Tomcat version is old enough, you may still be
> >> able to use the disable keep-alive trick.
> >>
> >> My own view was then, and is now, that the extra bytes with chunking are
> >> a price worth paying for the client to be able to determine if the
> >> request is complete. That said, an option on the connector to revert to
> >> non-chunked responses when keep-alive is disabled for use cases where
> >> reducing bandwidth is more important than knowing if the response is
> >> complete seems reasonable to me.
> >>
> >> Mark
> >>
> >> [1] http://issues.apache.org/bugzilla/show_bug.cgi?id=48738
> >> [2] http://svn.apache.org/viewvc?rev=931709&view=rev
> >> [3] http://svn.apache.org/viewvc?rev=932913&view=rev
> >> [4] http://markmail.org/message/pim62zhlw4cii7ve
> >>
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> >>
> >  		 	   		  
> 
> 
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