[ic] usefulness of mv_pc

Kevin Walsh interchange-users@icdevgroup.org
Thu Oct 10 02:05:00 2002


Jeff Dafoe [jeff@badtz-maru.com] wrote:
> 
>     mv_pc appears to start back at 1 for each new session.  In order to
> truly prevent caching, shouldn't it be a random number?  If aol or some
> equally-aggressive cache is caching
> www.mystore.com/mystore/0023.html?mv_pc=3 what would prevent this from being
> served from the cache to any sessions coming through that same caching
> server that happen to be requesting the same mv_pc value (which is most
> likely to occur within the first few clicks from the landing page)?
>     Would there be any repercussions if I were to modify the code to
> generate a random number?
> 
The mv_pc is really aimed at browser caches, rather than proxy caches.
Feel free to randomise the mv_pc if you think it'll help.

You'd probably be better off setting "ScratchDefault mv_no_cache 1"
in your catalog.cfg file, or setting [tmp mv_no_cache]1[/tmp] in some
of your files.  That would cause "Pragma: no-cache" to be added to the
HTTP header. I believe that AOL's cache recognises that pragma.  Correct
me if I'm wrong.

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