“An ETag (entity tag) is an HTTP response header returned by an HTTP/1.1 compliant web server used to determine change in content of a resource at a given URL. The value of the header is an opaque string representing the state of the resource at the time the response was generated.”— Microsoft Developer Network, msdn.microsoft.com
“Using the proxy_cache directive, we can specify that the backcache cache zone should be used for this context. Nginx will check here for a valid entry before passing to the backend.”— Justin Ellingwood, digitalocean.com
“Intelligent content caching is one of the most effective ways to improve the experience for your site's visitors. Caching, or temporarily storing content from previous requests, is part of the core content delivery strategy implemented within the HTTP protocol. Components throughout the delivery pat…”— Justin Ellingwood, digitalocean.com
“A web cache (or HTTP cache) is an information technology for the temporary storage (caching) of web documents, such as HTML pages and images, to reduce bandwidth usage, server load, and perceived lag.”— Wikipedia, en.wikipedia.org
“What is considered slow depends on your requirements. But when something becomes slow it's a candidate for caching.”— High Scalability, highscalability.com
“A cache’s eviction policy tries to predict which entries are most likely to be used again in the near future, thereby maximizing the hit ratio. The Least Recently Used (LRU) policy is perhaps the most popular due to its simplicity, good runtime performance, and a decent hit rate in common workloads.”— High Scalability, highscalability.com
“A few times in the last two years we’ve invalidated large swaths of cache or restarted memcached processes, and observed that our aggregate response time increases by 30-75%, depending on the amount of invalidation and the time of day. We then see caches refill and response times return to normal wi…”— Noah Lorang, signalvnoise.com
“The solution to caching GraphQL is to normalize the hierarchical response into a flat collection of records. Relay implements this cache as a map from IDs to records. Each record is a map from field names to field values. Records may also link to other records (allowing it to describe a cyclic graph…”— Facebook Engineering, facebook.github.io
“The recommendation for speeding up a website is almost always to add cache and more cache. And after that add a little more cache just in case.”— High Scalability, highscalability.com