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Posted to users@trafficserver.apache.org by he...@web.de on 2011/01/27 14:15:27 UTC
Asynchronous refresh
Hello,
is it possible to refresh/revalidate the cache asynchronously?
That means if a client triggers a refresh of an object stored in the cache,
could this request be served (with old data) from the cache and the
refresh done in the background?
Actually I'm not using traffic server but I need to know it traffic server could do this.
Most caching proxy servers stale the client until data from the backend are retrieved.
Why I need this:
The backend could take some time to render the data.
On a refresh I don't want that a user have to wait that long.
Workarounds?
"Common" workarounds like putting two caches in series seems not useful
because the same problem exists. The middle proxy would stale the frontend
proxy.
Purging and "warming up the cache" using PURGE + GET
reguests is really complex and would not be necessary if the async
refreshing would be somehow possible.
Do you know any other caching reverse proxy software that can do that?
I did not test it but from the docs and IRC it seems Varnish, Ngnix, apache
Webser can't do that and do block on refresh. At least I know squid can't do it.
Thanks in advance,
Philipp
___________________________________________________________
NEU: FreePhone - kostenlos mobil telefonieren und surfen!
Jetzt informieren: http://produkte.web.de/go/webdefreephone
Re: Asynchronous refresh
Posted by Mark Nottingham <mn...@yahoo-inc.com>.
See:
http://tools.ietf.org/html/rfc5861
Supported in Squid 2.7.
Cheers,
On 28/01/2011, at 12:15 AM, <he...@web.de> <he...@web.de> wrote:
> Hello,
>
> is it possible to refresh/revalidate the cache asynchronously?
> That means if a client triggers a refresh of an object stored in the cache,
> could this request be served (with old data) from the cache and the
> refresh done in the background?
>
> Actually I'm not using traffic server but I need to know it traffic server could do this.
> Most caching proxy servers stale the client until data from the backend are retrieved.
>
> Why I need this:
> The backend could take some time to render the data.
> On a refresh I don't want that a user have to wait that long.
>
> Workarounds?
> "Common" workarounds like putting two caches in series seems not useful
> because the same problem exists. The middle proxy would stale the frontend
> proxy.
>
> Purging and "warming up the cache" using PURGE + GET
> reguests is really complex and would not be necessary if the async
> refreshing would be somehow possible.
>
> Do you know any other caching reverse proxy software that can do that?
> I did not test it but from the docs and IRC it seems Varnish, Ngnix, apache
> Webser can't do that and do block on refresh. At least I know squid can't do it.
>
> Thanks in advance,
> Philipp
> ___________________________________________________________
> NEU: FreePhone - kostenlos mobil telefonieren und surfen!
> Jetzt informieren: http://produkte.web.de/go/webdefreephone
--
Mark Nottingham mnot@yahoo-inc.com