obj.cacheable vs expires headers?

Poul-Henning Kamp phk at phk.freebsd.dk
Mon Feb 8 20:55:41 CET 2010

In message <4B707680.6020205 at gmail.com>, Luc Stroobant writes:
>Poul-Henning Kamp wrote:

>> "can be cached" is a matter of correctness, whereas "how long" is 
>> just a performance issue.
>So you mean: the object /can/ be cached, but it would only be cached for 
>zero seconds?

Yes, that is a valid, but silly configuration.

>I don't think it's a clock issue. Varnish and the webserver are running 
>on the same host. We wanted to use Varnish to cache some static files on 
>an overloaded prefork Apache + mod-php (and it did a great job, till we 
>started to see weird session issues).

Ok, no, it's not a clock issue then.

Check your varnishlog output, it shows all headers sent/received
and look for what cache-control the backend gives varnish...


Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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