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Although search engines have developed very well, they still face many technical challenges, mainly including:
1. Page crawling needs to be fast and comprehensive
We know that the Internet is a dynamic content update. Every day, many people publish new content or update old content on the Internet. The search engine is to crawl the web pages that best meet the user's search intentions from this massive amount of information. Faced with With the massive amount of information that already exists and the amount of information growing geometrically every second, the workload of the search engine is very large. It takes a lot of time to update the search engine program, especially when it is just born. The cycle can sometimes be updated every few months. Just imagine, how many web page updates and new ones will be created in a few months? Such search results tend to lag. In order to return the best search results, search spiders must crawl as comprehensive a web page as possible, which requires search engines to solve many technical problems. This is also the main challenge it faces.
2. Mass storage of data
The information on the Internet is huge, almost unimaginable, and a lot of new information is generated every day. After search engines crawl these pages, they must be stored in a certain data format, and the data structure requires reasonable , and it must have very high scalability. The data writing speed must be fast, and the access speed must be fast enough. In addition to storing a large amount of information on the page itself, search engines must also store link relationships between pages, historical data on the page, and a lot of index information in order to better index and sort. The amount of these data is very huge. There are definitely many technical challenges in storing and reading such large-scale data.
3. Index processing must be fast and effective, and must be scalable.
After the search engine crawls and stores the page data, it also needs to index many pages. For example, calculation of link relationships between pages, forward index, reverse index, etc. For example, there is Google's PR calculation, etc. Search engines must perform a lot of indexing work to quickly return search results. Moreover, during the indexing process, a large number of new pages are generated, and the search engine's index processing program needs to be compared. Good scalability.
4. Query processing is fast and accurate
The previous steps are all run in the background program of the search engine, and the query stage is a step where users can see the results. After we enter keywords in the search box of the search engine and click search, the search engine can often return the results to us in less than a second. Although it looks simple on the surface, for search engines, it is actually a very complicated process. process. There are many algorithms involved. It needs to quickly find reasonable pages from web pages that meet basic conditions in less than a second and rank at the front of search engines. We know that Baidu can see up to 76 pages of results, and Google has a little more, and can see up to 100 pages of results.
Article source: http://www.suptb.cn/ Please indicate the source when reprinting, thank you
Thanks to danieldu2008 for his contribution