Databases Intermediate

What is Index?

A data structure that improves the speed of data retrieval operations on database tables at the cost of additional storage.

Indexes work like a book index — they allow the database to find rows without scanning the entire table. Without an index, a query on a million-row table checks every row. With an index, it jumps directly to matching rows.

Types include B-tree (default, good for ranges), hash (exact matches), GIN (full-text search), and GiST (geometric data). Over-indexing slows down writes since indexes must be updated on every INSERT/UPDATE.

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Related Terms

The default index type in most databases that organizes data in a balanced tree structure for efficient searching, sorting, and range queries.

An SQL operation that combines rows from two or more tables based on a related column between them.

Write-Ahead Log (WAL)

A technique where changes are first written to a log before being applied to the database, ensuring crash recovery and data integrity.

Database Backup

The process of creating copies of database data to protect against data loss from failures, corruption, or human error.

A centralized repository optimized for analytical queries that integrates data from multiple operational sources.

An open-source, in-memory data store used as a database, cache, message broker, and queue with sub-millisecond response times.

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