michigan informatics

How Search Engines Work: The Database

The search engine’s database is what you are actually searching. All of the information that a web crawler retrieves is stored in a database. Every time you use a search engine, it is this database you are searching, not the live Internet. Variable features which can affect your search results include:

• Size of the database
  Some search engines will have extremely large databases (~5 billion pages) for you to search, while others will have comparatively small ones (~150 million pages). A small database is not necessarily worse, however, since it may offer more focused and higher quality results than a larger database.
• Freshness of the database
  The freshness of the database is a direct result of how frequently the web crawler retrieves new information. If the information in the database is fairly old, then your search results will suffer.