Mailing List Archive: [rubenste@ohiou.edu: Re: help?]

Something to do with web proxies and caching?

----- Forwarded message from "steven l. rubenstein" <rubenste@ohiou.edu> -----

From: "steven l. rubenstein" <rubenste@ohiou.edu>
Date: Fri, 14 Feb 2003 14:01:01 -0500
To: Jimmy Wales <jwales@bomis.com>
Subject: Re: help?

Hi,

I am having a strange and irritating problem: whenever I click on recent
changes, all I get are changes as recent as "18: 38" which was about 20
minutes ago. If I click on "last 50 changes" I get the last 50 changes
starting from the present time. But if I click on "recent changes" again I
go back 20 minutes into the past!

Also, when I try to open an article I only get the version as of 20 minutes
ago. Only if I click on "edit this page" do I then see the current version.

I cleared my cache (which is the only thing I can think of) and I am not
having problems on any other web-pages.

If this isn't a problem on your end, I am sorry to bother you!

Steve

Steven L. Rubenstein
Assistant Professor
Department of Sociology and Anthropology
Bentley Annex
Ohio University
Athens, Ohio 45701

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(CC'd to slrubenstein)

On Fri, 14 Feb 2003, Jimmy Wales wrote:
> > Also, when I try to open an article I only get the version as of 20 minutes
> > ago. Only if I click on "edit this page" do I then see the current version.
>
> Something to do with web proxies and caching?

If it's regularly 20 minutes off, that could be due to a combination of
bad clocks -- our server is 4 minutes slow, and if a proxy server is 16
minutes slow and doesn't obey the caching instructions we give it, it may
not bother to pass on requests to verify that pages are current. (Even
though all pages are pre-expired and a "must-verify" cache control is
set, so it really should check.)

(Incidentally, if there's anyone more familiar with caching issues than I,
please take a look at the headers we send to see if they're correct.
There may also be some funny interaction with PHP's session handling
system that could be sending conflicting headers, but I'm not sure.)

As a temporary workaround, try a browser other than Internet Explorer --
pages should then be marked as uncacheable and it would take a *very*
broken proxy to not obey that. (If you're using Opera, make sure it's set
not to identify itself as Internet Explorer.)

-- brion vibber (brion @ pobox.com)