Index

Search engine, Information retrieval

Definition
Make data available immediately that otherwise would require a scan.

This pattern collects documents, parses them and feeds the structured content into a data structure that is optimized for retrieval.

Indexing architecture diagram

The purpose of storing an index is to optimize speed and performance in finding relevant documents for a search query. Without an index, the search engine would scan every document in the corpus, which would require considerable time and computing power.

Examples

  • Search engines

When should you use it?

  • If your user needs immediate access to information

Problems

  • It can take a lot of space to index documents
  1. Wikipedia on search engine indexing