On 25/09/2006, at 10:41 PM, Francesco Fuzio wrote:
<<It is important to understand that caching of *result lists* is done independently from caching of *individual DataObjects and DataRows*. Therefore the API is different as well. Also cached results lists _are not synchronized across VMs (even the shared cache)._>>__So it seems that if my application is deployed in a cluster I have to implement a custom _distributed_ invalidation mechanism.
It depends on how important it is that the data is up to date. One solution might be to add functionality to Cayenne which invalidates objects in the cache after a certain period of time (for instance 1 hour). It is now possible to invalidate objects one at time (http:// cwiki.apache.org/confluence/display/CAYDOC/RefreshQuery)
We are examining the same problem in our application (not a web cluster, but a client/server application). For now we switched off caching, but we need to think through the issues. One solution is to implement a distributing messaging system to send notifications between clients - I think Andrus was looking at XMPP at one time (http://www.xmpp.org/summary.html) for this. Certainly it would be handy if a messaging system was built into Cayenne for this. It would also be useful for things like pessimistic locking.
Ari Maniatis --------------------------> ish http://www.ish.com.au Level 1, 30 Wilson Street Newtown 2042 Australia phone +61 2 9550 5001 fax +61 2 9550 4001 GPG fingerprint CBFB 84B4 738D 4E87 5E5C 5EFA EF6A 7D2E 3E49 102A
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