How a Typical Google Search is Performed
- When you click the Google Search button, your query is transmitted over the Internet to Google's web server.
- Google's web server sends your query to the company's array of index servers. These computers hold a searchable index to Google's database of web pages.
- Your query is matched to listings in the Google index - that is, the index servers determine which actual web pages contain words that match your query.
- Google now passes your query to the document servers, which store all the assembled web listings (documents), in the Google database.
- The document servers assemble the results page for your query by pasting together snippets of the appropriate stored documents.
- The document servers send the assembled results page back to the main web server.
- Google's web server sends the results page across the Internet to your web browser, where you view it.
Source: Googlepedia by Michael Miller