What is caching in computer science?
The concept of caching is fundamental in computer science and affects both computers and applications. From RAM to mobile and web applications, caches are present at various levels and their crucial function is to speed up data access. In the context of a web application, caching significantly improves efficiency and performance.
How is caching implemented in a web application?
In a web application, the caching process starts from the browser. Let's explore how this process is carried out and how it benefits applications in production.
Caching in the browser
When a user enters a URL, the browser makes a call to this address. If no cache existed, the browser would have to access the server's file system directly to obtain, for example, a JavaScript file. This type of access is costly in terms of time compared to data stored in memory.
Using CDNs as a cache tier
Applications in production use Content Delivery Networks (CDN) as the first level of caching. A CDN is a service that specializes in distributing files such as JavaScript, CSS or HTML across globally distributed servers. This allows content to be delivered quickly and efficiently. First accesses may require a server query, but once stored in the CDN cache, subsequent access is much faster.
Caching on the server
After the CDN, the request can be directed to an intermediate web server such as Apache or Nginx, which may be configured to have their own internal cache. This capability allows servers to store and deliver files faster without having to recalculate or re-access the original source on each request.
Caching in the application
Within the application itself, there are multiple levels to implement caching. A common example is caching a complex computation, such as generating a JavaScript file that requires data from the database. When calculating it for the first time, it can be stored in RAM and then the file can be provided from the cache, thus optimizing response time.
What technologies make it possible to improve caching?
In addition to the methods mentioned above, advanced caching technologies are used to further enhance application efficiency.
RAM memory usage
RAM is a valuable resource for caching because of its speed compared to traditional database access. Classically, data and calculated results can be stored in RAM.
External caches: Redis and Memcached
Redis and Memcached are specialized external cache management solutions that significantly increase performance. They store data in memory, which allows extremely fast accesses. These technologies are popular because of their ability to reduce latency in applications by caching critical information and frequent queries.
Integration into web applications
Frameworks such as Rails allow you to easily integrate external caches such as Redis or Memcached, configuring them to store frequent API queries. This integration is essential for web applications that require optimal performance, allowing users to have a smooth and enhanced experience.
Caching transforms the way web applications manage data access, making initially costly operations fast and efficient. Understanding and correctly applying caching techniques not only improves the user experience, but also optimizes server resources, becoming a key competency in software development.
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