On Thu, 21 Oct 2004 14:57:28 -0400, Vadim Gritsenko
<[EMAIL PROTECTED]> wrote:
> Pier Fumagalli wrote:
> 
> 
> > On 21 Oct 2004, at 04:22, Vadim Gritsenko wrote:
> >
> >> Store:
> >>   "Clean out" here writes stuff out into the persistent store,
> >>   if stuff is Serializable.
> >> Transient store:
> >>   "Clean out" here removes stuff completely, hence the
> >>   name: "transient".
> >> Persistent store:
> >>   Janitor does not touch this store at all. No "clean out"
> >>   happening at all.
> >
> > So, given that the cache is caching in the persistent store, who cleans
> > it out? The cache itself? This is getting _waay_ to frisky for my taste :-(
> 
> Cache caches into Store. Store overflows into PersistentStore when low on memory
> or on shutdown (*).
> 
> Cache cleans up stale items on "as-detected" basis, or, if you use event cache
> pipelines, stale items removed as per external events (**).
> 
> Vadim
> 
> * Might not work with JCS / EHCache implementations
> ** Don't know much about this event stuff myself

You're right about the event-based cache validities - not much more to
say about it in this context.

Also, the unbounded nature of the persistent store (especially as it
relates to the overflow from the cache) has always worried me.  I'd
much prefer to see cached entries examined periodically and if they
can be determined to be invalid, removed.  But, in practice this
apparently has not caused noticeable problems or surely we would have
heard about it?

Geoff

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