DynamoDB Indexing and Design Patterns: GSI, LSI, and Key Concepts Explained

DynamoDB offers two types of secondary indexes — Global Secondary Index (GSI) and Local Secondary Index (LSI) — each suited to different query patterns, with GSIs allowing a different partition key and LSIs restricted to the same partition key as the base table. Sparse indexes improve efficiency by only indexing items that contain a specific attribute, reducing unnecessary storage and read costs. Features like TTL, PITR, and optimistic locking help manage data lifecycle, recovery from accidental deletions, and safe concurrent updates respectively. Hot partitions, caused by uneven traffic on a single partition key, can be mitigated through thoughtful key design and DynamoDB's built-in adaptive capacity feature. The core design principle is to model data around how it will be accessed rather than how it is structured, making access-pattern-first thinking essential for effective DynamoDB table design.