06. Amazon DynamoDB
Amazon DynamoDB is a fully managed, serverless NoSQL database service that provides fast and predictable performance with seamless scalability. It is designed for applications that require single-digit millisecond latency at any scale.
⚙️ Features
- Fully managed and serverless no servers to manage
- NoSQL database supporting key-value and document models
- Automatically scales with demand
- High availability with replication across 3 Availability Zones (AZs)
- Handles millions of requests per second, trillions of rows, and hundreds of terabytes of data
- Fast and consistent performance with single-digit millisecond latency
- Integrated with AWS IAM for security, authorization, and administration
- Cost-effective with on-demand, provisioned, and auto-scaling capacity modes
- Supports Standard and Infrequent Access (IA) table classes for cost optimization
| Component | Description |
|---|---|
| Table | Container for items (like a collection or table) |
| Item | A single record in a table (similar to a row) |
| Attribute | A field within an item (similar to a column) |
| Primary Key | Uniquely identifies each item. Can be: • Partition key (single key) • Partition + Sort key (composite key) |
| Data Model | Flexible – you can add attributes without schema changes |
⚙️ Performance & Scaling
- Serverless – No need to manage infrastructure.
- Automatic Scaling – Adjusts read/write capacity based on traffic.
- High Availability – Data replicated across 3 AZs in a region.
- Durability – Designed for 99.999% availability.
⚡ DynamoDB Accelerator (DAX)
DAX (DynamoDB Accelerator) is a fully managed in-memory cache for DynamoDB.
| Feature | Description |
|---|---|
| Purpose | Improve read performance by caching frequently accessed data |
| Performance | Up to 10x faster – from milliseconds to microseconds |
| Integration | Fully integrated with DynamoDB (not general-purpose like ElastiCache) |
| Use Case | Ideal for low-latency, high-read workloads |
📌 If the cache is missed, DAX automatically retrieves data from DynamoDB.
🌍 DynamoDB Global Tables
Global Tables enable multi-region, multi-master replication of DynamoDB data.
| Feature | Description |
|---|---|
| Purpose | Provide low-latency data access across regions |
| Replication | Two-way replication between up to 10 AWS Regions |
| Access | Read/Write in any region (Active-Active) |
| Benefit | Global high availability and disaster recovery |
Example:
- Table in
us-east-1(N. Virginia) - Global replica in
eu-west-3(Paris) - Both regions can read/write data with automatic synchronization.
🧠 Exam Tips
| Keyword | Meaning / Association |
|---|---|
| Serverless Database | DynamoDB |
| Low Latency | Single-digit millisecond latency |
| Caching for DynamoDB | DAX |
| Global Multi-Region Replication | Global Tables |
| NoSQL / Key-Value Data Model | DynamoDB |