Rickard �berg wrote:
>
> <vendor>
> I have added an option to the previously mentioned singleton feature
> which allows the deployer to select whether calls to the singleton
> instance should be synchronized or not. I have also added
> configurability in the deployment GUI for this option.
>
> If synch. is off the performance of usage of singletons is improved, but
> the bean writer must take care so that concurrent use is really
> supported. Read-only state is preferred.
>
> jBoss users can pick up this new feature from the CVS repository.
> </vendor>
<vendor>
Sybase EAServer also supports this feature (shared singletons with optional
concurrent use). We have supported this since version 2.0, and many of our
customers use it for caching read-only or read-mostly data to improve
performance (in some cases by several orders of magnitude).
</vendor>
Note: even if you choose to serialize access to a shared singleton, you don't
necessarily get bad performance. Consider the fact that the alternative may
be to not do any caching at all, i.e. synchronizing on a shared singleton may
be faster than running zillions of JDBC queries.
________________________________________________________________________________
Evan Ireland Sybase EAServer Engineering [EMAIL PROTECTED]
Wellington, New Zealand +64 4 934-5856
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