Internship← Elasticsearch learning pathElasticsearch · Module 2 of 10
The inverted index
An inverted index maps each word to the documents that contain it.
📖 Key ideas
- Text is split into tokens (words) when indexed.
- Each token points to the list of documents that contain it.
- Search looks up the tokens instead of scanning every document.
- Analyzers lowercase words and remove punctuation before indexing.
- Stemming can make "running" and "run" match.
💡 Real-life example: Like a school register by subject: under "Maths" you see every student who takes it, without opening every file.
TokenOne word or term after splitting text
Inverted indexTerm to document list mapping
AnalyzerTurns text into tokens
StemmingReducing words to their root