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From Alexei Kosut <>
Subject Re: performance ``bugs'' in apache-1.1b4's P-HTTP
Date Wed, 10 Jul 1996 21:45:38 GMT
On Wed, 10 Jul 1996, John Heidemann wrote:

> I've found a couple of interactions between Apache-1.1b4's P-HTTP and
> SunOS TCP that significantly reduce performance.  A web page
> summarizing the problems and containing patches resolving them is now
> available at
> <>.  (The
> abstract of the web page is attached below.
> I encourage the Apache core team to look at these problems and
> proposed solutions.  If you agree with the analysis,
> then the patches (or their equivalents) should be added to a future
> Apache release.

Wow... this looks useful. We'll certainly look into this.

One note, though: The first problem you note, which has to do with Apache
sending its headers as a seperate segment, cannot unfortunately just be
removed. Unfortunately, Netscape Navigator has a rather serious bug in its
Keep-Alive implementation - if the end of the file is in the same read as
the headers, it will not recognize properly that it is dealing with a
persistent connection, and the connection will hang, waiting for a close.
So we added the fflush() to the code to make sure that it reads the body
seperate from the headers.

Obviously, we'd perfer not to do this, but Netscape makes up 60%-80% of
the market (depending on who you ask), so it really wasn't feasible. One
option is, I suppose, to only do the fflush() for files less than whatever
Netscape's read buffer size is (I tested for this a couple month ago when
I first wrote the keep-alive code, but I now forget - it was 256 or
1024 bytes, or something of the sort).


-- Alexei Kosut <>            The Apache HTTP Server

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