Cache hit definition
A cache hit is an event in which the requested content is successfully found and served from the cache memory. A cache hit is a fast data retrieval method because the content is deployed from the closest memory location, which is usually the cache server, instead of the origin server, which can be located across the globe, meaning that the data will have to travel much farther. Additionally, there is a metric called the cache hit rate or ratio, which is a measure of the cache’s effectiveness. More specifically, it shows the percentages of data requests that are successfully found and served by the cache rather than the origin server. The higher the cache hit rate, the more effective the cache is. Also, cache hits can help improve the speed and performance of a website, which can result in a better user experience and higher customer conversion rates.
Different cache hit types
- Cold cache hit: This type of cache hit has the slowest data retrieval times. Of course, cold cache hits are still successful. They just take a lot of time to read and find the data. Usually, these cache hits happen when the data is stored in the lower tiers of the memory hierarchy, like L3.
- Warm cache hit: Faster than a cold cache hit, this cache hit type refers to finding and retrieving data from the L2 or L3 memory levels.
- Hot cache hit: This is the fastest type of cache hit, and retrieves data from the highest level of the cache hierarchy, typically L1.