Title: Message

I completely agree.

One example brought in the F2F was that of a load-balanced (a.k.a., clustered) Consumer, who - if we enforce an invalidation algorithm - MUST communicate to the other servers in the clusters in order to discard an invalidated cached, and handle it consistently in a concurrent environment (race conditions etc.).

Hopefully nothing else in the spec mandates intra-cluster communication at the Consumer level, and if that's the case, we probably want to deal with it in a well-thought-of fashion, as Mike suggested.

Eilon

-----Original Message----- From: Michael Freedman [mailto:Mich...@oracle.com] Sent: Sunday, February 09, 2003 9:16 PM To: wsrp...@lists.oasis-open.org Subject: Re: [wsrp-wsia] [change request #128] cache invalidation due to perform*Interaction()

My preference is that we stick with the decision we made in the November F2F which recognized the complexities of invalidation caching and deferred any specification of such until after 1.0. Our current model is based on a well understood and time tested caching model. Invalidation, though ultimately an important developers tools for achieving optimal performance needs our time and energy to specify a complete and flexible solution. Our current solution is satisfactory. As cache maintanence is controlled by the consumer, consumers are free to provide the semantics you describe in this change control and market themselves as a better solution without our specification saying anything about invalidation. Portlets running on systems without this feature merely receive "stale" data/content -- something that is inherent in caching systems/portals/consumers anyway.

Some reasons for deferring: We should be concerned about implementability by the consumer. Though some consumers will deal with the complexities of implementing invalidation based caching, we shouldn't require all consumers to do so. Such consumers, however, will likely find it easy/convenient to implement our current caching semantics. Ultimately, work should be done to allow consumers to support caching levels. Adding wording/function as you are suggesting to our current specification prevents such behavior.

We should be concerned about extensibility in the future to provide a richer solution. Though, all or nothing invalidation is both convenient for the developer and affords an easy specification, our experience shows that this ultimately must be coupled with a more flexible invalidation model where the portlet can explicitly control each piece of content to be invalidated. Though more work, [invalidation] caching is about optimization and optimization in general involves more work/a deeper knowledge to the true nature of interactions. -Mike-

Rich Thompson wrote:

>Document: Spec >Section: 6.2.1.2 >Page/Line: 39/10 >Requested by: Rich Thompson >Old text: [insert new paragraph] >Proposed text: Consumers invoking either performInteraction() or >performBlockingInteraction() MUST treat any markup cached for the >equivalent MarkupParams (i.e. the MarkupParms structure passed to the >invocation updated with any honored newMode or newWindowState requests and >any returned navigationalState) as if the expiry time had elapsed unless >the response includes a new CacheControl structure indicating the cached >markup is still valid. > >Reasoning: I had promised last Wednesday to post a proposal for how >interaction processing impacts cached markup. > >---------------------------------------------------------------- >To subscribe or unsubscribe from this elist use the subscription >manager: <[1]http://lists.oasis-open.org/ob/adm.pl> > >

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