Re: [squid-users] Question about PURGE

Thanks Amos,

J

On Tue, 2009-11-10 at 01:47 +1300, Amos Jeffries wrote:
> John G. Moylan wrote:
> > Hi,
> >
> > I have an app which sends PURGE's to squid caches on demand or on
> > document changes. It testing this works fine and I am making PURGE
> > requests on document changes as part of a publish event. 200 or 404
> > responses are almost instantaneous as all of the servers are on the same
> > network.
> >
> > Hoe does squid execute the PURGE internally? Does it mark the object in
> > the cache to be PURGE'd the next time the object is requested or does it
> > remove as soon the item when the PURGE request is made? Will there be
> > situations when a PURGE requests might time out on a busy Squid? It is
> > advisable to have my publisher Queue up PURGE requests in a separate
> > thread or process?
>
> Lot of questions ;).
>
> Squid needs to scan the object cache to find the matching URL then
> update any of several indexes of information for erasure.
>
> Squid treats PURGE like any other request and does not reply until its
> finished. As such it _may_ timeout before being run. The problem though
> is that on a busy cache the PURGE request is likely to be the most
> resource hungry operation going and block other requests being accepted.
>
> Yes it's advisable to spread them out rather than bunch them up. For the
> reason above.
>
> Amos

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Received on Mon Nov 09 2009 - 14:16:29 MST