[Zope-PTK] Topics support in PTK

[Michael Bernstein]

Tres Seaver wrote:
> 
> On Tue, 13 Feb 2001, Michael Bernstein wrote:
>
> > Starting from the 'other' implementation, how much extra
> > work to add caching?
> 
> I'm not confident that we can do a reasonable job of caching
> the result sets without re-introducing dependencies on catalog
> internals (which is the real Achilles heel of ZTopics).

Hmm. If I understand your drift here, The current ZTopics
implementation relies on the catalog internals in order to
*invalidate* the cache in some way, otherwise merely caching
the result set would not be much of a problem.

So it sounds as though the catalog (and ZCatalog) needs an
invalidation interface that other objects can call, or it
needs to take over the task of caching result-sets
internally, freeing ZTopics (or your own implementation) of
the requirement.

Recently, at my suggestion, caching was added to the Meerkat
product to lower the latency for expensive XML-RPC queries,
but it doesn't check for invalidation, merely a simple
timeout.

HTH,

Michael Bernstein.