Caching (pronounced “cashing” or “kash-ing”) is a technique used by computers and web browsers to speed up the process of accessing and retrieving data.
For example, you’re browsing a website that has a lot of images and videos. Every time you click on a new page or refresh the page, your device needs to download all of that content again, which can slow down your browsing experience.
But if the website uses caching, your computer or device will store some of that content locally (i.e., on your device or computer’s local disk) so that it doesn’t need to be downloaded again. This can make your browsing faster and smoother because your device can quickly access the cached content instead of downloading it from the internet each time.
Caching can also be used in other ways, like when you’re using an app that needs to access data frequently. Instead of constantly retrieving that data from a server, the app can store it locally so that it can be accessed more quickly.
Caching can also reduce the load on servers, as the cached data can be served directly from the user’s computer or device instead of being retrieved from the server every time. This can help improve web applications and websites’ overall performance and reliability.
Different Kinds of Caching
The idea that caching involves storing commonly used data in memory to enable fast access applies not just to internet caching but also to other types of caching, including:
When your computer’s processor (CPU) needs to access data from memory, it can take a long time to retrieve it. To speed up this process, CPUs have a small amount of built-in cache memory that stores frequently used data. This way, the CPU can quickly access the data it needs without retrieving it from slower memory.
Websites and web applications often use server-side caching to store frequently accessed data on the server side. This can include things like images, scripts, and other content that doesn’t change often. By storing this data in cache memory, the server can quickly serve it to visitors, improving the site’s overall performance.
When you enter a website URL in your browser, your computer needs to look up the IP address associated with that URL using the Domain Name System (DNS). This process can take some time, but many devices and network systems use DNS caching to store this information locally. This way, if you revisit the same website later, your device can quickly retrieve the IP address from cache memory instead of looking it up again.
Content delivery networks (CDNs) use content caching to store frequently accessed content in cache memory on servers distributed worldwide.
This can improve performance for users in different geographic locations since they can access the cached content from a nearby server instead of retrieving it from the original source.
Database caching stores frequently accessed data in cache memory to speed up queries and improve overall performance. This can include query results, commonly accessed tables, or often-used data.
Many applications use caching to store data locally so that it can be accessed quickly and efficiently. This can include user settings, frequently accessed data, and other application-specific data. By storing this data in cache memory, the application can quickly retrieve it instead of having to retrieve it from a remote server or database.
Caching is a widely used technology to improve performance, but it also has drawbacks. One downside is that a browser can cache sensitive data, which unauthorized users could access.
Another issue is that cached data can become outdated or incompatible with the original source data. Additionally, a huge cache can have a negative impact on performance.
While caching is a useful technology to improve performance, it can also negatively impact if the wrong data is cached.
An application first checks the cache for the data it needs, and if it’s found, it’s a cache hit, but if it’s not, it’s a cache miss. And when it’s a cache miss, then the application must retrieve the data from the primary source, which can add an extra step to the data retrieval process.
Too many cache misses can lead to poor performance and defeat the purpose of caching.
To maximize the benefits of caching, it’s essential to plan carefully and make informed decisions about what data to cache and how long it should be retained.
For example, if the data changes frequently, it might be best to limit how long it’s retained in the cache or avoid caching it altogether.
There are multiple factors to consider when determining the best approach to caching, including the type of cache being used, the characteristics of the data being cached, and the applications that will be accessing the cached data.