Re: caching proxies and SVN network perf

Brian Behlendorf <brian@collab.net> writes:
> Bob has a SVN tree with a file foo.c, v1.5.
> Jane has a SVN tree with a file foo.c, v1.6.
> The current repository has been updated, and has v1.7.
>
> I do an update. I get the diff(1.5,1.7) long-distance from the central
> server, and that is cached by the proxy.
>
> Jane does an update. SVN determines she needs diff(1.6,1.7), the cache
> sees it doesn't have that, and gets it long-distance from the central
> server.
>
> This isn't optimal, since the proxy already "has" that delta.

I don't think it does have that delta, actually.

There could be a change in the 1.6-1.7 delta that is simply not
present in the 1.5-1.7 delta. For example:

   1.5-->1.6: adds line L
   1.6-->1.7: deletes line L, but adds character X elsewhere
   1.5-->1.7: just adds character X, therefore

There is no way the cache can deduce 1.6-1.7 from 1.5-1.7.
Received on Sat Oct 21 14:36:12 2006