I had a contract at a company about 13 years ago where I was working on a web-based CMS that had been built entirely in-house. Because each rendered page's cont

I had a contract at a company about 13 years ago where I was working on a web-based CMS that had been built entirely in-house. Because each rendered page's content was built up in a hierarchical manner, I added a caching layer that allowed arbitrary portions of the rendered page "tree" to be cached all the way up to the entire page and HTTP response if possible. Each cached portion could be located quickly based on its dependencies (template ID, content ID, CSS etc). If any edits were made to the site, only the relevant portions needed to be flushed and re-rendered. User-specific portions could be cached in the user's session rather than site-wide. (Thinking about it now, each portion could have been rendered in parallel too, though this was back in the days when multicore machines weren't very common and it wasn't something that occurred to me.) I built this without giving much thought to whether anyone else had attempted something similar. Presumably they had though I do remember being disappointed when researching the various open source caching libraries, they didn't offer much help at the time. Overall I was pretty happy with the way it all worked and the performance boost it provided was like night and day. Sadly the company is no longer operating, presumably the CMS codebase is long lost.