集群环境中的单例

问题描述

将Singleton对象重构为集群环境的最佳策略是什么?

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

我们使用Singleton从数据库中缓存一些自定义信息.它的主要是只读，但是在发生某些特定事件时会刷新.

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

现在，我们的应用程序需要部署在集群环境中.根据定义，每个JVM将具有其自己的Singleton实例.因此，当在单个节点上发生刷新事件并刷新其缓存时，JVM之间的缓存可能不同步.

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.

保持缓存同步的最佳方法是什么?

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

谢谢.

缓存主要用于向UI提供自动完成列表(出于性能原因)，我们使用Websphere.因此欢迎任何与Websphere相关的技巧.

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

推荐答案

最简单的方法是:

1. 在单例缓存中添加一个到期计时器，以便每隔一段时间就会清除一次缓存，随后的调用会从源(例如数据库)中获取更新的数据

1. Add an expiry timer to your singleton cache so that every so often the cache gets purged and subsquent calls fetch the updated data from source (e.g. a database)

使用诸如JMS topic/tibRV之类的东西实现缓存的通知机制.获取每个缓存实例以订阅并响应此主题上广播的任何更改消息.

Implement a notification mechanism for the cache using something like a JMS topic/tibRV. Get each cache instance to subscribe and react to any change messages broadcast on this topic.

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