Hi Magnus, The documention you are looking for is here : https://www.varnish-cache.org/docs/4.0/reference/vcl.html
And beresp.keep is definitely what you are looking for. If ttl is expired but not ttl + keep, varnish will issue a conditionnal request. -- Guillaume Quintard On Fri, Sep 18, 2015 at 12:35 PM, Magnus Hoff <[email protected]> wrote: > Hi :) > > What is the status of support for conditional backend requests? > > My use case is accelerating CouchDB, which has good support for ETags, > but offers no other caching opportunities. > > I have found [1] which leads me to think that the branch implementing > this feature was merged to trunk in 2011. According to [2] (which also > says, in big bold letters, "This documentation is out of date"), I > should be able to see this working with the default VCL: "In the > default case (i.e. if not superseded by something in VCL), a > conditional request is generated during fetch with If-Modified-Since > and/or If-None-Match headers whose values are taken from stale_obj's > Last-Modified and/or ETag headers." > > [1]: > https://www.varnish-cache.org/lists/pipermail/varnish-commit/2011-July/006720.html > [2]: https://www.varnish-cache.org/trac/wiki/BackendConditionalRequests > > However, when testing with the latest Varnish from the Varnish Ubuntu > repository (https://www.varnish-cache.org/installation/ubuntu), > "varnish-4.0.3 revision b8c4a34", I am unable to trigger conditional > backend requests in the default configuration. I have feebly tried > making the VCL more explicit in that it should try to keep the ETagged > versions around by setting beresp.keep explicitly, but I can't seem to > effect a change in behavior. > > So, what is happening? Does Varnish currently support what I am > looking for? What is the up to date documentation on this? Is there > support for this on a branch still? How is that branch coming along? > > > Thank you :) > - Magnus Hoff > > _______________________________________________ > varnish-misc mailing list > [email protected] > https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc >
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