Introduction to Inverted indexes in search engines

Inverted indexes are abstract concepts. Inverted tables, temporary Inverted Files, and final Inverted Files are specific manifestations.

Full-text search: 1) All Keywords of the document participate in the index; 2) the search results provide the actual location of the keyword.

In search engines, webpages are information and keywords are indexes. A structured webpage object (a structure containing the title, body, URL, and other information) is called a document, and a webpage number is called a document number. The numbering method has MD5, but the storage consumption of BITs is still too large, so differential encoding can be used to compress the storage.

Forward Index

1) local ID of the localid document

2) wordid index word number

3) Number of times the nhits index word appears in the document

4) location of the hitlist index word in the document

Inverted index

Part 2: an index table composed of different index words, called a "Dictionary ". Stores various Chinese words and their statistical information for various rankingsAlgorithm.

Part 1: it consists of a collection of documents with indexed words and hit positions. It is called "record table" or "record list ".

Process of creating inverted Indexes