Abstract Algorithms

Category

search engine

2 articles across 2 sub-topics

Understanding Inverted Index and Its Benefits in Software Development

TLDR TLDR: An Inverted Index maps every word to the list of documents containing it — the same structure as the back-of-the-book index. It is the core data structure behind every full-text search engine, including Elasticsearch, Lucene, and PostgreS...

Mar 9, 2026•14 min read

Elasticsearch(1)

How Apache Lucene Works: The Engine Behind Elasticsearch

TLDR: Lucene is a search library. Its core innovation is the inverted index — a reverse map from words to documents, like the index at the back of a textbook. Documents are stored in immutable segments that Lucene merges in the background to keep que...

Mar 9, 2026•13 min read