James Strachan wrote:
On 30 Jan 2006, at 10:06, Jules Gosnell wrote:
Finally, as discussed with James on numerous occasions, we should
look at how WADI's pessimistic locking and PartitionManager might be
componentised so that they can be plugged into AS to provide Cache
and Space users, who are not interested in location- independance,
with a pessimistic approach and/or a partitioned clustering
substrate...
BTW I don't see using a pessimistic lock as being very useful for a
cache; typically in a JCache scenario you are caching state that is
stored in some database/system; so if you really want a pessimistic
lock you should lock the database (they are very good at doing
distributed locks) rather than having a pessimistic lock in a cache
which is a different lock to where the actual data is.
Agreed - but in the case of a distributed session, it may not be mapped
to a database.... - I guess we are not a typical JCache scenario ?
Optimistic locks are much more efficient & useful in a distributed
caching system (which is why we implemented them in ActiveSpace).
Though using the PartitionManager as a way of implementing a sparse
cache is a good endevour. Incidentally ehcache has support for
distributed caching now...
http://ehcache.sourceforge.net/
I will revisit it ...
Maybe we can persuade the ehcache team to adopt the JCache API and
plug in any distributed strategies or sparse caching strategies into
that. (ActiveSpace was using the RI of JCache which is less
functional than ehcache)
Sounds like an idea :-)
Jules
James
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