Elasticsearch: More Than Just Search

How does Google search work? How does Amazon find products so fast? They use Inverted Indexes.

The Inverted Index

Instead of mapping Document -> Words, it maps Word -> Documents.

• "Apple" -> [Doc 1, Doc 3]
• "Banana" -> [Doc 2]

This makes full-text search O(1).

Elasticsearch Features

1. Fuzzy Search: Finds "iPhone" even if you type "ipone".
2. Aggregations: "Count products by category" (faster than SQL GROUP BY).
3. Scalability: Distributed by nature. Splits indexes into shards across nodes.

The ELK Stack

Elasticsearch + Logstash + Kibana. The industry standard for searching and visualizing server logs.