Caching in ASP.NET Core Web API

Caching in ASP.NET Core Web API

In this article, I will give a Brief Introduction to Caching in ASP.NET Core Web API Application. Please read our previous articles discussing Logging in ASP.NET Core Web API with Examples. At the end of this article, you will understand the following pointers, which are also frequently asked interview questions:

  1. What is Caching?
  2. What is Caching in ASP.NET Core Web API?
  3. Why is Caching Important in Web API?
  4. What is a Cache Hit and a Cache Miss?
  5. What is Cache Warming?
  6. What are the Different Types of Caching Available in ASP.NET Core?
  7. What are the Main Differences Between In-Memory Caching and Distributed Caching?
  8. Describe a Scenario Where Caching Might Not Be Appropriate
  9. How does Distributed Caching Affect Database Load and Application Performance?
  10. What are the Different Distributed Caching Techniques Supported by ASP.NET Core Web API?
What is Caching?

Caching is a mechanism for storing frequently accessed data in a temporary storage area called a cache. Its purpose is to speed up data retrieval by avoiding expensive operations like database queries or API calls.

What is Caching in ASP.NET Core Web API?

In ASP.NET Core Web API, caching stores commonly requested data, such as database query results or static files, so that it can be quickly retrieved from the cache without the need for repeated processing. This improves application performance.

Why is Caching Important in Web API?

Caching improves application performance by reducing load on backend systems. It can also significantly enhance user experience by minimizing the number of calls to a database or API.

Let us understand why coaching is important by using one example. Suppose our application contains static data (Static data means data that does not change frequently, such as Products, Countries, States, Cities, Configurations, etc.) and multiple users want to access it.

In this case, without caching, each time we request static data, it hits the database. Every time it hits the database, it increases the load on the server as the number of round trips between the application server and database server increases, which also decreases the overall application performance. For a better understanding, please have a look at the following diagram.

Caching in ASP.NET Core Web API

Now, with caching, when the first request comes to the server, it will hit the database, fetch the data, store it in the cache memory (a temporary storage area, mostly in the RAM), and return the data to the user. Now, from the next request onwards, for example, when Request 2 and Request 3 come, the server will get the data from the Cache memory and return the data to the client. So, with caching, we are reducing the number of database round trips, which will reduce the load on the backend server and ultimately improve the overall application performance. For a better understanding, please have a look at the following image.

Caching in ASP.NET Core Web API Application

What is a Cache Hit and a Cache Miss?

A cache hit occurs when the requested data is found in the cache, leading to faster data retrieval. A cache miss happens when the data is not found in the cache, resulting in a slower fetch from the primary storage or database.

What is Cache Warming?

Cache Warming is the process of pre-loading the cache with necessary data at startup or after a cache flush before it is actually needed. This avoids cache misses and performance drops when the system is newly started.

What are the Different Types of Caching Available in ASP.NET Core?

ASP.NET Core supports several types of caching:

  • In-memory Caching: In this case, data is stored in the web server’s Memory (RAM). This is simple to implement, very fast, and ideal for single-server scenarios.
  • Distributed Caching: In this case, it uses external cache stores like Redis or SQL Server. This is suitable for applications running on multiple servers in a load-balancing environment.
  • Response Caching: In this case, it caches the responses of HTTP requests to improve the response time for similar requests. Stores the output of a request and reuses it for similar requests.
What are the Main Differences Between In-Memory Caching and Distributed Caching?

The main differences between In-Memory Caching and Distributed Caching are as follows:

  • Storage Location: In-memory caching stores data on the web server’s memory (where the application is hosted), whereas distributed caching stores data on a shared external server.
  • Scalability: In-memory caching is limited to the server where it is running, making it less suitable for distributed applications and not suitable in a load-balancing environment. Distributed caching can support multi-server configurations, making it better for high availability and well-suited in load-balancing environments.
  • Persistence: In-memory cache is lost if the server restarts. Distributed caches can retain data when the server restarts.
Describe a Scenario Where Caching Might Not Be Appropriate.

Caching might not be suitable for data that changes frequently, where the overhead of keeping the cache updated exceeds the benefits of caching. Additionally, caching is less effective for data that is rarely reused or accessed, as it consumes valuable memory resources without providing benefits.

How does Distributed Caching Affect Database Load and Application Performance?

Distributed Caching impacts application performance by reducing the load on the database and decreasing the time of data retrieval. By storing frequently accessed data in a cache that is faster to access than a database, the number of SQL queries to the database is reduced, reducing the load on the database. As the data is retrieved more quickly from the cache, the overall response time of the application improves, leading to a better user experience.

What are the Different Distributed Caching Techniques Supported by ASP.NET Core Web API?

ASP.NET Core Web API supports multiple distributed caching techniques. They are as follows:

  • Redis: A high-performance, open-source, in-memory key-value data store that is often used as a distributed cache. It is highly popular due to its performance and features.
  • SQL Server: The SQL Server database stores cache data. It is a good option for environments already using SQL Server, providing a simple integration.
  • NCache: A native .NET distributed caching technique that is fully integrated with ASP.NET Core, offering high performance and scalability.

In the next article, I will discuss How to Implement In-Memory Caching in ASP.NET Core Web API Applications with Examples. In this article, I explain Caching in ASP.NET Core Web API Application with Examples. I hope you enjoy this article, Caching in ASP.NET Core Web API.

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