On Fri, Sep 12, 2003 at 07:34:24PM +0200, Thomas Leske wrote:
> Edgar Friendly wrote:
> >let me get this clear, you're proposing to have nodes pretend they
> >don't have data?  This seems to have the downside of non-probabilistic
> >caching (ending up throwing out more data from the network)
> 
> The downside of non-probabilistic caching was not that the nodes always
> put the data into their cache. This just caused data to be dropped
> that was equally unimportant. Pcaching will drop the data, even if
> there are still gigs of free space left in the data store.

Only on a very large store - we drop only after the store is 90% full.

> The problem was that the caching worked too well. Data may not seem
> to be popular from a single nodes view, because the requests were
> distributed amoung too many nodes. Because of that nodes dropped the
> wrong data items.
> 
> >as well as
> >the downside of probabilistic caching (successful requests take longer
> >to find data).
> 
> Most of the time they will only take one hop more.
> 
> >It does have the upside that unlike probabilistic
> >caching, it won't make requests fail even when their path goes over a
> >node that has seen the data recently, but I'm still not seeing the
> >worth of this proposal.
> 
> One can not decide beforehand, if caching data is good or bad.
> If the node that you route to is overloaded or it considers the
> data to be popular anyways, then dropping the data was a bad decision.
> On the other hand if our node caches the data, this might cause
> the data to be dropped on the node that is in the "shadow" of ours.
> This is bad, if the network prefers routing to that node.
> 
> The proposal postpones the decision. The node always caches the
> data and propagates new requests for the data as unimportant.
> The response tells it, if caching was a good decision. If not,
> the node behaves as if it had not cached the data.
> 
> --
>  Thomas Leske
-- 
Matthew J Toseland - [EMAIL PROTECTED]
Freenet Project Official Codemonkey - http://freenetproject.org/
ICTHUS - Nothing is impossible. Our Boss says so.

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