> --- Ursprüngliche Nachricht --- > Von: Robert Borkowski <rborkows@xxxxxxxxxxx> > An: alpheus@xxxxxx > Kopie: squid-users@xxxxxxxxxxxxxxx > Betreff: Re: Question to internal behaviour of squid > Datum: Wed, 20 Jul 2005 13:17:49 -0400 > > alpheus@xxxxxx wrote: > > Hi, > > > > I have a general question to the internal behaviour of squid as a > reverse > > proxy: > > > > Imagine there is a webserver which uses squid as a reverse proxy to > serve > > the content. > > If a user request a site A for the first time, squid has to request A > from > > the server. > > No let's image that this server needs several seconds to generate the > site > > A, e.g. 5 seconds. > > My question: what happens if a second user (and many more) requests the > same > > site A in this 5 second time slot? > > Does squid request site A again from the server or does it know that > there > > is already a pending request? > > > > So, it is of interest for me if in such a long time slot a lot of > identical > > requests would be sent to the webserver or if squid is maintaining a > list > > that already a request is running and subsequent calls are put into a > queue. > > > > Hope, my question is clear!? > > > > Thx in advance, > > alp > > > > Yes, when a new request comes in for an object that is 'in flight', the > second client will join in on the transfer. One interesting effect is > that if there is a speed difference between clients, and the object is > large enough then the faster client will be forced to transfer at the > same speed as the slower client. This is due to squid having a limit to > the read-ahead difference between the client and origin server. > > The read-ahead amount is tunable in squid3. > > I found this out the hard way while fighting a very frustrating and > intermittent failure at our site :-) > > -- > Robert Borkowski > Thx Robert, just to make it clear to me: Each client request for the same object causes an own request from squid to the server (during the time slot to bring the object into the cache)? Resulting possibly into a large number of request to the server for the same object if generating the object takes a long time? Thx, alp -- GMX DSL = Maximale Leistung zum minimalen Preis! 2000 MB nur 2,99, Flatrate ab 4,99 Euro/Monat: http://www.gmx.net/de/go/dsl
