How does search engine give me the answer I want? [closed]

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Each time, when we type the key-words in Google, how does Google give us its answers? I want to know the process of how Google process our requests.

Personally, I assume that:

1.there are a huge amount of queries sent to Google, in order to respond ASAP, Google gotta have some kinda distributed system, right?

2.also, I think there are some kind of cache systems to speed up Google's response speed, right?

3.If cache indeed exists, what is stored in开发者_如何学C that cache? Could it be some kind of <key, value> pair? Cuz I guess that, it's <key-words, url>. But would be it be too expensive to cache url directly, because each url will probably take up many memory, right?

UPDATE:

After skimming the keynote suggested by @Gregory Pakosz, I wondering what the Cache Server is responsible for and what the Cache Server caches?

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Jeff Dean's 2009 keynote: Challenges in Building Large-Scale Information Retrieval Systems gives a pretty nice overview of how Google works.