Cache enhancements in Java caching technology

Every Java developer knows that caching plays a vital role in improving performance. However, caching doesn't always work as we expect. In some cases, caching can also add overhead and complexity. In this article, we'll explore some cache enhancement techniques that can help us better utilize caches and optimize them if necessary.

1. Batch Caching

Suppose we have a common query that needs to retrieve records corresponding to multiple IDs from the data source. According to the traditional way of querying, we would loop through each ID and perform a separate query. However, in some cases, the load on the data source may delay the response time of each query. At this time, the advantages of batch query are obvious. We can put all the IDs into a collection and pass the collection to the query. This will allow the data source to execute a query and return all results.

Similarly, we can cache the results of batch queries instead of executing separate queries for each ID. This can significantly reduce communication with the data source, improve performance, and reduce load.

2. Element-level cache clearing

Sometimes in an application, we only want to clear a part of the cache instead of completely clearing all caches. For example, our application requires an "adaptive" cache that can automatically adapt to changes in the data source without affecting the entire application. In this case, we need a way to selectively clear the cache.

Java's Ehcache API allows us to clear the cache by pressing a key. However, when used in a distributed environment, clearing the key may affect the cache on all nodes. At this time, element-level cache clearing comes in handy. This approach allows us to selectively clear specific elements in the cache collection without affecting the cache of other elements.

3. Asynchronous loading

In some cases, the time to load the cache may be very long. For example, we might need to access an external API or execute lengthy SQL queries. In this case, synchronous loading may cause performance issues in our application.

Fortunately, asynchronous loading can help us solve this problem. Asynchronous loading will allow us to perform loading operations in a background thread so that our application can continue to perform other tasks. When the loading is complete, we can store the result in the cache so that we can use it later.

4. Local cache

Distributed cache is very convenient in a multi-node cloud environment. However, in a single-node environment, using a local cache would be more appropriate. Local caching tends to be faster than distributed caching because data cached in the local node is accessed faster.

ConcurrentHashMap introduced in Java 8 allows us to map weakly referenced keys to strongly referenced values. This means that when a key is no longer used by the application, the cache can automatically recycle the corresponding cache entry. This type of local cache is ideal for applications with high concurrency and large data volumes.

Summary

Caching is a key factor in improving application performance, but improper use can lead to negative effects. Using cache enhancement technology can help us better utilize the cache and optimize it when necessary. The above technologies not only improve application performance but also enhance application scalability and robustness.

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