On Wed, 27 Aug 2014 16:17:17 +0000 Rasim Saltuk Alakuş <rala...@turksat.com.tr> wrote:
> > Hi All, > > ATS uses URL hash for cache storage. And CacheUrl plugin adds some more > flexibility in URL hashing strategy. > > We think of creating hash based on packet content and use it as the hash > while storing and retrieving from cache This looks a better solution, so that > URI changes won't hurt caching system. One immediate benefit for example if > you cache YouTube , each request for same video can have different URL and > CacheUrl plugin does not always provide a good solution. Also maintaining > site based hash filters looks not an elegant solution. > > Is there any previous or active work for implementing content based hashing? > What kind of problems and constrains you may guess. Is there any volunteer to > implement this feature together with us? It would be straightforward enough to implement, though I think rather expensive in computation. But what does it gain you? A possible many-to-one URL to local cache map, but you still have to deal per-URL with all the complexities like content negotiation and cache validation. Indeed, the whole scheme is BAD (Broken As Designed). Using different URLs for common content breaks cacheing on the Web at large, and hacking one agent (such as Trafficserver) to work around it will gain you only a tiny fraction of what you've thrown away. Indeed, if every agent on the Web - from origin servers to desktop browsers - implemented this cacheing scheme, you'd still lose MOST of the benefits of cacheing, as the same content passes through different paths. -- Nick Kew
