Elasticsearch
Master the distributed search and analytics engine that powers full-text search, geo queries, and real-time aggregations at scale. From inverted indices to vector search.
Inverted Index & Text Analysis
The foundation of everything — how ES turns text into searchable tokens and why reads are fast.
Core Architecture
Shards, nodes, clusters, and how ES distributes data for scale and resilience.
Query DSL & Relevance
Full-text search, term queries, bool composition, BM25 scoring, and function_score.
Aggregations & Analytics
Bucket, metric, and pipeline aggregations — ES as a real-time analytics engine.
Operations & Tuning
Index design, ILM, performance tuning, vector search, and when NOT to use ES.
Why Elasticsearch?
SQL LIKE '%query%' doesn't scale and has no relevance ranking. Elasticsearch solves full-text search with inverted indices, BM25 scoring, and distributed execution — returning ranked results in milliseconds across billions of documents.
- ✓Inverted index architecture — sub-second full-text search with relevance ranking.
- ✓Distributed by design — horizontal scaling via shards across nodes.
- ✓Real-time aggregations — analytics over millions of documents in parallel.
- ✓Rich query DSL — full-text, geo, nested, vector search in one engine.