How do you measure and improve the cache hit ratio of your web app?

1 Why cache hit ratio matters

The cache hit ratio is a key indicator of how well your web caching strategy is working. A high cache hit ratio means that your web app is delivering most of the requests from the cache, which means faster response times, lower server load, and less network traffic. A low cache hit ratio means that your web app is relying more on the origin server, which means slower response times, higher server load, and more network traffic. Therefore, you want to aim for a high cache hit ratio, but not too high, as that could mean that your cache is storing stale or irrelevant data that is not being updated or invalidated properly.

2 How to measure cache hit ratio

There are different ways to measure the cache hit ratio of your web app, depending on the type and location of your cache. For example, if you are using a browser cache, you can use the browser's developer tools to inspect the network requests and see how many of them are served from the cache. If you are using a reverse proxy cache, such as Nginx or Varnish, you can use their logging or monitoring features to track the cache hits and misses. If you are using a content delivery network (CDN), such as Cloudflare or Akamai, you can use their analytics or dashboard tools to see the cache hit ratio and other metrics. Alternatively, you can use a third-party tool, such as Google PageSpeed Insights or WebPageTest, to measure the cache hit ratio and other performance aspects of your web app.

3 How to improve cache hit ratio

Once you have measured the cache hit ratio of your web app, you can take some steps to improve it and enhance your web caching strategy. For instance, you can set appropriate cache headers using HTTP headers, such as Cache-Control, Expires, ETag, and Last-Modified. Additionally, you can use cache busting techniques by adding a unique query string or version number to your web app's resources, like images or scripts. Furthermore, you can use cache invalidation methods to remove specific data or content from the cache when they are no longer valid. Lastly, you can use cache segmentation techniques to store and serve different types of data or content based on certain criteria. This can help increase the cache hit ratio by reducing the cache misses and improving the user experience.

5 How to optimize cache hit ratio

Finally, you need to optimize the cache hit ratio of your web app by finding the optimal balance between caching too much and caching too little. Caching too much can lead to serving stale or irrelevant data or content that can harm your web app's functionality and user satisfaction. Caching too little can lead to relying too much on the origin server that can harm your web app's performance and scalability. Therefore, you need to analyze your web app's data or content and determine how frequently and dynamically they change, how important and sensitive they are, and how diverse and demanding your users are. Based on that, you can adjust your web caching strategy and fine-tune your cache headers, cache busting techniques, cache invalidation methods, and cache segmentation techniques accordingly.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?