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Date: Wed, 2 Feb 2005 11:40:48 -0500
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From: PMilanese@nypl.org
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Subject: RE: [users@httpd] Apache Performance Issue

Is apache doing dns resolutions?

HostnameLookups...

> -----Original Message-----
> From: Grader, Matt - AES [mailto:Matt.Grader@itt.com]
> Sent: Wednesday, February 02, 2005 11:24 AM
> To: users@httpd.apache.org
> Subject: [users@httpd] Apache Performance Issue
> 
> 
> Hello,
> 
> We have observed several bizarre performance issues with Apache that I
am
> hoping someone out there has experienced, and can detail the root cause
of
> the problem and what steps are needed to correct it.
> 
> 
> We have noticed poor performance from several different machines running
> older versions of IE (usually IE 4 or 5 but sometimes IE 6).  On these
> machines and browser configurations  (and only these) every 4th - 5th
page
> request hangs.  A page that loaded fine five minutes ago may hang now -
> there is no consistently in what pages hang.   The page usually
partially
> loads and then stops loading for 2 up to 8 minutes at which point the
page
> will continue loading until completion.   Our pages are very small
(around
> 200k for html + images) and the machines we tested each had a broadband
> connection (Using Firefox the pages load in around 5 seconds).
> 
> Our configuration was Apache 2.0.44 with SybPerl 1.2 (an old Sybase perl
> application).
> 
> We have done the following trying to discover the root cause:
> 
> 1.	Add logging to our SybPerl scripts.  We found that during a hang,
> the script executes successfully and in a normal amount of time (less
than
> 2 seconds)
> 2.	Examined the Apache logs and increased the loglevel.  During a
hang
> Apache does not log either an access or error (even though from our
> SybPerl logs we know the script is called and fully executes).  At the
> highest reporting loglevels we see the following error:
> [info] (32)Broken pipe: core_output_filter: writing data to the network
> 
> 3.	Packet Sniffed the connection.  When the client sends a request
and
> hangs, it sends the first request successfully and opens a connection
(tcp
> three way handshake).  This connection eventually dies and the client
> sends a new request several minutes later (2-8 minutes) and then fully
> loads the page.  We did detect ICMP messages being sent when a hang
> occurs, but these are blocked by our firewall (which our Network
> Administrator assures me is normal for security reasons).
> 
> We have noticed that two things will resolve the issue:
> 
> 1.	In the internet settings of the computer experiencing the problem,
> disable HTTP 1.1 and use HTTP 1.0 instead. No hangs occur.
> 
> OR
> 
> 2.	Roll back Apache to v1.3 (the latest) from our original 2.0.44.
> 
> At the moment we have resolved the problem by rolling back Apache, but
we
> would still like to migrate to Apache 2 sometime in the future.  If you
> have any constructive ideas / suggestions your help would be greatly
> appreciated.
> 
> Thanks.
> 
> Matt
> matt.grader@itt.com
> 
> 
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