The Ultimate Guide to Locking Cache in ASP.NET

When developing ASP.NET applications, you may encounter situations where multiple users can trigger long-running processes concurrently. This is particularly common when caching data that users frequently request. The challenge arises when one user’s request initiates a long-running procedure while another user’s request simultaneously checks the cache only to find an empty slot. In such cases, we risk executing the same process multiple times, which can lead to inefficiencies and increased load on your server.

In this blog post, we will explore the best way to implement cache locking techniques in ASP.NET to optimize performance and prevent needless duplicate processes.

Understanding Cache Locking

Cache locking is the practice of preventing concurrent access to a shared resource. When a request finds that a cache entry is not available, rather than executing the long process again, the request will “wait” until the process is completed and the cache is filled. This helps ensure that multiple processes do not run in parallel unnecessarily.

Let’s break down how you can implement cache locking step-by-step.

Step-by-Step Implementation of Cache Locking

Here is a clear approach you can follow to implement locking in your ASP.NET application:

1. Check the Cache

Initially, you will want to check if the desired value is already in the cache. If it’s available, you can return it immediately, avoiding further processing.

// try to pull from cache here

2. Implement the Lock

If the value isn’t found in the cache, it’s time to introduce a lock. The lock prevents other requests from entering the critical section of code until the current request completes.

lock (ThisLock)
{
    // cache was empty before we got the lock, check again inside the lock

3. Recheck the Cache

After acquiring the lock, check the cache again. Another request may have filled the cache while you were waiting for the lock.

// cache is still empty, so retrieve the value here

4. Perform the Value Look Up

If the cache is still empty, proceed to perform the necessary lookup or long-running process to acquire the value. After that, make sure to store this value in the cache for future requests.

// store the value in the cache here

5. Release the Lock

Once you’ve cached the new value, it’s important to release the lock so that subsequent requests can proceed.

// return the cached value here

The following snippet showcases these steps in code:

private static object ThisLock = new object();

public string GetFoo()
{
    // try to pull from cache here

    lock (ThisLock)
    {
        // cache was empty before we got the lock, check again inside the lock

        // cache is still empty, retrieve the value here

        // store the value in the cache here
    }

    // return the cached value here
}

Conclusion

Locking cache in ASP.NET is a crucial technique to optimize resource utilization and maintain application performance, especially during long-running processes. By systematically checking the cache and applying locks as needed, you can significantly reduce unnecessary resource consumption.

Implementing this strategy will not only make your applications faster but also ensure a smoother experience for your users, who will benefit from quicker responses and reduced load times.

For more insights and techniques related to ASP.NET development, stay tuned to our blog!