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Re: Main Memory Ozone?
Johann, I Cc: this to the list because it could be of general interest.
On Mon, 15 May 2000, you wrote:
> >%_Hi guys,
>
> Could you tell me if it is doable to develop a Main Memory store for
> Ozone? I mean something that would store objects into memory
> rather than on disk. What does it implies for Ozone?
>
> The Ode object database seems to have something like that:
> http://www-db.research.bell-labs.com/projects/ode/ode-announce/#mmode-desc
>
> Does it make sense for Ozone? My first interest would be to have a
> very fast repository for objects, not necesseraly persistent given the
> fact that Javaspaces objects are not necesseraly persistent themselves.
If persistency is cut of ozone, transaction handling and client-server
features are the only benefits of ozone over a simple hastable. If this is
what you want, then it should be no problem to write a simple in-memory version
of the Store back-end. In fact, throwing an OutOfMemoryException in the
core.wizardStore.ClusterStore.ensureCacheSpace() method and some slight
changes in core.wizardStore.ClusterStore.commitCluster() should change the
wizardStore into an inMemoryStore.
Anyway, I'm not sure if this would boost performance that much. If the cache
(heap of the server VM) is able to hold the entire working set of data, then
all operations are done in-memory, except for writing changed clusters after
commit. If speed has higher priority than durability of transactions results in
your environment than a write-back cache is probably a better solution. I'm
very interested in such a solution too. IMO for many application types it is
acceptable to loose say 1 of 1000000 transactions (after a server crash or
something) if the other 999999 transaction are much faster. Such a solution
would be fast *and* persistent - in most cases ;) (and much harder to implement
of course)
Falko
--
______________________________________________________________________
Falko Braeutigam mailto:falko@softwarebuero.de
softwarebuero m&b (SMB) http://www.softwarebuero.de