Cache Hit Vs. Cache Miss – What is The Difference?

Caching is the process of storing your site’s data to make them easily accessible for further visits to reduce data recovery time. You can effectively speed up your website speed by caching your WordPress install.

But, unfortunately, the cache won’t work appropriately without a proper setup. This will slow down your page load time by delaying serving your site’s content to the readers. In fact, this can even lead your site to get miss penalties.

By knowing the difference between cache hit vs. cache miss, you can get how the caching system can be organized to achieve maximum performance. In this guide, I’ll share the details about cache hits and cache misses.

So, to know further, keep reading this useful guide.

Caching and How It Works?

Before jumping into cache hit vs. cache miss, it’s crucial to understand the caching process. So, let’s get started.

A cahe is a fast-performing memory that temporarily saves data and content from a website. For example, when you set up a cache on your site, it starts memorizing your content when loaded and then creating a static version. That way, when visitors visit your site next time, that content is displayed much faster.

This implies, when your site’s data and content get stored into cache memory, it’s known as “caching.” It helps your web page load much faster for a better user experience.

Cache usually stores data in a hierarchy of levels, and they are labeled as L1, L2, L3, and go on. When someone requests data from the cache, a search is made to find the specific content needed in L1 of memory by tag.

If accurate data is not available there, further searches are performed on L2. Just like that, the searches continue until the data is found in L3, then L4, and so on. After that, it’s read and loaded onto the page. A cache hit and miss is related to this process when the data is read from the cache.

Cache Hit Vs. Cache Miss

Cache hits and misses indicate whether the data requested by the audience is delivered directly from the cache volume or from the original volume.Cache Hit Vs. Cache Miss

The occurrence of cache hits or misses depends on the availability of the requested data in the cache, the difference between the attribute cache timeout value and the cache file properties, and the origin.

So, let’s find out what cache hit and miss really are and how they work.

Cache Hit

When a reader sends a read request, and your site content is successfully served from the cache instead of the server, it describes a cache hit. In other words, readers search the tags repeatedly, and when the data is found and read, this situation is considered as a cache hit.

The cache hit is described as cold, warm, and hot caches in terms of the speed at which the data is read.

  • A hot cache: Here, the data was read from memory at the fastest possible rate. This instance happens when the cache retrieves the data from level one.
  • A cold cache: When it comes to data to be read, It is the slowest possible rate. The data is found lower in the memory hierarchy with a cold cache, as in level three or lower.
  • A warm cache: With a warm cache, the data is found in level two or three. Though it’s not as fast as a hot cache, it is still faster than a cold cache.

Here is the hit ratio, which calculates cache hits and compares them with the number of total content requests received. Cache Hit ratio

Cache Miss

A cache miss occurs exactly in the opposite situation. Here, the site requests content from the cache, and after searching for it, first, the cache determines that the content wasn’t saved. After that, the cache saves the content so that it’s become available next time when requested.

This means, when the memory is searched, the data isn’t found there. And when this instance happens, usually the data is transferred and written into the cache.

A miss ratio is the opposite of a hit ratio, where you can calculate the miss ratio and compare it with the total number of content requests received.Cache miss ratio

Usually, a cache miss takes up additional time and server resources, which leads the page speed load time to slow down. One cache miss doesn’t affect the loading time that much, but the more cache misses happens, the worse it’ll be for your server resources and loading time.

And this is where the miss penalties come into the picture. To avoid more cache miss, you can set up an expiry date to the lifespan of the cache. It is the amount of time that stores in the cache before it’s purged, and your site is cached again.

Some other ways are optimizing your site, minifying HTML, CSS, and JavaScript files, enabling CDN caching, LazyLoad for images, and installing caching plugins.


Hopefully, now you understand a little more about cache hit vs. cache miss from this comprehensive guide. So, taking help from this guide, calculate the hit and miss ratio in cache memories and understand how well your cache is performing.

In this way, you can also find out how to optimize your site’s cache. In addition, this way, you can also determine if your page load times are consistently fast for your users or not.

This is the end of this guide. So, how do you plan on increasing cache hits on your WordPress site? Are there other areas you’re unclear about? Share your experience and thoughts in the comments below with me.

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