Document DB

Core Characteristics

• AWS-native document database service

• MongoDB-compatible API

• Managed NoSQL database for JSON documents

• Automatic storage scaling

• Support for both write-then-read and eventual consistency

Architecture

Instance Configuration

• Single primary instance + up to 15 read replicas

• Document data redundantly stored across availability zones

• Primary instance handles all writes

• All instances (primary and replicas) can handle reads

High Availability Features

• Automatic failover to read replica if primary fails

• Multiple endpoint types:

  • Reader endpoint (all read instances)

  • Writer endpoint (primary instance)

  • Custom instance endpoints

  • Group endpoints for instance subsets

Document Structure

• JSON-based documents

• Flexible, schema-less design

• Allows adding/removing fields without schema changes

• Documents retrieved as complete units

• Intuitive structure for developer usage

Use Cases

• User profiles storage

  • Single document contains all user data

  • Intuitive format for user information

• Real-time big data applications

  • Efficient handling of document-based data streams

• Content management systems

  • Natural fit for content storage

  • Flexible schema supports varied content types

Key Features for AWS Exam

1. Scalability

   • Built to handle any data storage size

   • AWS-managed auto scaling

2. MongoDB Compatibility

   • Emulates MongoDB API

   • Suitable for MongoDB migrations

   • Primary solution for MongoDB workloads on AWS

3. Development Focus

   • Flexible JSON schema

   • Natural development experience

   • Fast iteration capability