[jboss-user] [JBoss Cache] New message: "Re: How to manage empty data with a CacheLoader?"

[Manik Surtani]

User development,

A new message was posted in the thread "How to manage empty data with a CacheLoader?":

http://community.jboss.org/message/524184#524184

Author  : Manik Surtani
Profile : http://community.jboss.org/people/manik.surtani@jboss.com

Message:
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This is a common problem with cache stores.  If stuff isn't in memory there is every chance it is stored elsewhere and this must be checked.
 
Optimising the cache store will help to some degree, but if most of your threads result in cache misses, then you should rethink why you use a cache store (or even a cache!) in the first place.  
 
Starting with optimisation, the JDBC cache store is one of the slowest, due to remote network connections and all sorts of bottlenecks in databases, combined with the fact that most databases need to be tuned extensively to start performing.  One recommendation is to consider other forms of cache storage.  BDBJE is a good engine, fast and powerful.
 
If you have to live with a JDBC backend, I recommend taking a look at Infinispan's JDBC cache store - a complete rewrite from the JBoss Cache one, and with some interesting optimisations in place that will help perform better.  Note that Infinispan's JDBC cache store is not compatible with JBoss Cache, but you could enhance JBoss Cache's implementation using similar techniques.
 
But both of the above techniques just improve the performance of the cache store and not really solve your problem.  Regarding your solution of using a "dummy entry", this does make sense provided you have a known and finite set of keys.  But if you know this set of keys and it is finite, then why do you use a cache store, since if it is to deal with persisting evicted objects, then you would still always have to check the store for existence of the object.
 
Cheers
Manik

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