A few users see a blank page

[Arne Kepp]

(Maybe this should be on -misc ?)

I've seen one odd (to me) problem like this that I was able to reproduce 
consistently, thanks to the help of a user. If you are serving PHP, and 
PHP is gzip'ing the output then clients behind a Squid proxy (on their 
end) only get blank pages.

Squid records something like "TCP_MISS/200 416 GET <script name>? - 
DIRECT/<ip address> text/html" in the logs, but doesn't appear to get 
the page.

Moving gzip compression from PHP to Apache solved this particular 
problem, but I still have users reporting blank pages every now and 
then. I've been accused of blocking all sorts of clients for this reason.

My VCL file is simple, it's the standard logic + lookup for image and 
css extensions and pass for everything else (also tried pipe).

-Arne

Marco Molinari wrote:
> Hi,
> I recently deployed Varnish and its performance is simply incredible.
> I'm having a problem, though, which made me jump back to Squid. In the
> week I used Varnish I had some users mailing me that they couldn't see
> the site anymore, they just saw a blank page.
> It seems this affects a small percentage of the users, as I got just
> about 10 emails in a week and my users are in the 10000s, and in fact
> I didn't notice any problem in the stats; so I setup two servers, one
> with Squid and the other with Varnish, and the affected users see the
> site only through Squid.
>
> I'm trying to understand what's happening and with the help of some
> users here's what I discovered:
> - every user who has problems connects from an office (completely
> different places, of course)
> - at least one user connects via a proxy (she has a header that says
> "Via: 1.1 SRVFW1")
> - Apache serves the page, which is logged with the correct size
> - they can see very small pages (a test I did just printed "Thanks " +
> the timestamp)
>
> This happens both with 1.1.2 and trunk.
>
> On standard log files I can't find anything, I couldn't even know it
> was happening if those users didn't email me. I'd like to have more
> data before submitting a bug report; do you have any suggestion on how
> and what I could collect?
>
> Thanks
> Marco Molinari
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