GSI vs LSI

In this lesson you will learn gsi vs lsi in DynamoDB, why it matters within local secondary indexes, and how to use it correctly with clear, copy-ready examples.

GSI vs LSI Overview

GSI vs LSI is a building block you will reach for often in DynamoDB. It keeps related logic together and makes your intent obvious to reviewers and future maintainers.

When you learn gsi vs lsi properly, you avoid the guesswork that leads to bugs and rework. The example below shows the shape you will use in most real DynamoDB projects.

import { DynamoDBClient } from '@aws-sdk/client-dynamodb';
import { DynamoDBDocumentClient, QueryCommand } from '@aws-sdk/lib-dynamodb';

const client = new DynamoDBClient({});
const docClient = DynamoDBDocumentClient.from(client);

const { Items } = await docClient.send(new QueryCommand({
  TableName: 'Orders',
  KeyConditionExpression: 'pk = :pk AND begins_with(sk, :prefix)',
  ExpressionAttributeValues: { ':pk': 'USER#42', ':prefix': 'ORDER#' },
  Limit: 25,
}));

QueryCommand reads a partition efficiently using key conditions; add IndexName for a GSI.

GSI vs LSI Example

import { DynamoDBClient } from '@aws-sdk/client-dynamodb';
import { DynamoDBDocumentClient } from '@aws-sdk/lib-dynamodb';

const docClient = DynamoDBDocumentClient.from(new DynamoDBClient({}));
// docClient.send(new PutCommand(...)) etc.

Start from a minimal GSI vs LSI example and grow it only as needed.
Keep configuration explicit so GSI vs LSI behaves the same in every environment.
Name things clearly so teammates understand your GSI vs LSI at a glance.
Add tests around GSI vs LSI early to lock in expected behaviour.

Amazon DynamoDB Cheatsheet

Handy DynamoDB (AWS SDK v3) reference related to gsi vs lsi.

Operation	Command	Purpose
Create/replace	`PutCommand`	Write an item
Read one	`GetCommand`	Fetch by primary key
Update	`UpdateCommand`	Modify attributes
Delete	`DeleteCommand`	Remove an item
Query	`QueryCommand`	Efficient key-based read
Scan	`ScanCommand`	Full-table read (avoid)
Transaction	`TransactWriteCommand`	Atomic multi-item writes

How GSI vs LSI Works in DynamoDB

GSI vs LSI builds on DynamoDB's key-value and document model, where every item lives in a partition chosen by its partition key and is optionally ordered by a sort key.

QueryCommand reads a partition efficiently using key conditions; add IndexName for a GSI.

Design access patterns first, then model keys around them.
Prefer Query over Scan for predictable performance.
Use expressions to read and write only what you need.
Keep items small and avoid hot partitions.

Practical Guidance for GSI vs LSI

In production, gsi vs lsi should be cost-aware and resilient. Right-size capacity, handle throttling with retries, and lean on indexes to support your query patterns.

Concern	Recommendation
Performance	Query by key; avoid table scans
Cost	Use on-demand or right-sized provisioned capacity
Modeling	Design for known access patterns
Reliability	Retry throttled requests with backoff

Common Mistakes

Copying gsi vs lsi snippets without understanding what each line does.
Skipping error handling and edge cases when wiring up gsi vs lsi.
Leaving gsi vs lsi untested, so regressions slip into production.
Over-engineering gsi vs lsi before you actually need the extra flexibility.

Key Takeaways

GSI vs LSI is a core part of working effectively with DynamoDB.
Start small and keep gsi vs lsi focused on a single responsibility.
Apply consistent patterns so gsi vs lsi scales across your project.
Test and document gsi vs lsi to keep it maintainable over time.

Pro Tip

Pair gsi vs lsi with automated tests from day one. It is far cheaper to catch DynamoDB regressions in CI than in production.