Singleton in Cluster environment

java singleton websphere cluster-computing
lud0h picture lud0h · Jul 28, 2009 · Viewed 36.9k times · Source

What is the best strategy to refactor a Singleton object to a cluster environment?

We use Singleton to cache some custom information from Database. Its mostly read-only but gets refreshed when some particular event occurs.

Now our application needs to be deployed in a Clustered environment. By definition, each JVM will have its own Singleton instance. So the cache may be out-of-sync between the JVM's when a refresh event occurs on a single node and its cache is refreshed.

What is the best way to keep the cache's in sync?

Thanks.

Edit: The cache is mainly used to provide an autocomplete list (performance reasons) to UI and we use Websphere. So any Websphere related tips welcome.

Answer

Chris Vest picture Chris Vest · Jul 28, 2009

Replace your singleton cache with a distributed cache.

One such cache could be JBoss Infinispan but I'm sure that other distributed cache and grid technologies exist, including commercial ones which are probably more mature at this point.

For singleton objects in general, I'm not sure. I think I'd try to not have singletons in the first place.

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