What is the search engine caching mechanism

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Baidu will be updated almost every week, and will usually choose to update in the wee hours of stillness. The update described here is the search engine's cache update. This article will give you a brief introduction to the search engine caching mechanism.

Search Engine Caching

Caching is also the cache, is a very commonly used in the field of computer technology, we are most familiar with, I am afraid that the browser's cache.

The search engine's cache can be described as simple: a data store in 11585.html "High speed Memory" > Hardware device that stores search queries, indexed data, intermediate results of searches, or final search results. The size of the cache is limited and it is not possible to store data indefinitely. Therefore, the search engine will take the cache update policy and cache elimination strategy to manage the data stored in the buffer.

The value of search engine caching

Search engine cache has two values: first, to speed up response search user query speed, improve the search user experience; second, reduce the search engine background calculation, save computational resources.

Search Engine Cache Update strategy plays an important role in improving the experience of search users.

Today is May 26, 2013, in Baidu Search "xiamen seo" This keyword, we can see, in the top ten sites Baidu, Baidu snapshot of different. The latest Baidu snapshot is May 21, 2013, some May 18, 2013, and some May 19, 2013.

Snapshots of different sites are not the same, why is this so? Because each site updates frequency and weight vary. Even if the use of different keywords to search the same site, the site will also show a difference Baidu snapshot. Why? Because of the search engine cache. You search "xiamen seo" The word returned by the search results, it is likely that the search engine directly in the buffer directly to the result of the call. Because the buffer is directly matched to your search, the search engine does not need to recalculate the sort.

Even if you have new updates on your site, and search engines index the latest content on your site, when you search for certain keywords, you can still see only the old site content, because the cached content doesn't change as the index content changes. This inconsistency has more or less affected the user experience.

In order to keep indexed content as much as possible with cached content, the search engine introduced two caching update Strategies: Cache-Index Close coupling strategy, Cache-index decoupling strategy.

Talk about the more detailed content of these two caching update policies. Interested comrades, can buy Zhang Junlin wrote "This is the search engine-the core technical details," a book. Whether you are a webmaster, or SEO optimization commissioner, or a search engine is interested in amateurs, I believe that after reading, you will have a lot of harvest. Article first A5, reproduced please indicate SEO blog http://pengjinjie.com/, respect for copyright!