I tried to appreciate your response, but I cannot fairly judge the code. For example, those could be performance uncritical parts of code or remnants of 20 year

I tried to appreciate your response, but I cannot fairly judge the code. For example, those could be performance uncritical parts of code or remnants of 20 year old code where the cache was less effective than now. Are 2000 search results a lot in a source of this size? Cache, as opposed to 20+ years ago, or whenever the pattern was developed, is indeed a thing that everyone is using just now.