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Aishwary Gathe
Aishwary Gathe

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Understanding Different Types of Databases in AWS: When to Use What?

Selecting the right database is one of the most important decisions in application architecture. AWS offers multiple database services, each designed with a specific purpose in mind — from storing files at scale to handling millions of transactions per second.

In this blog, we’ll break down popular AWS database solutions, explain how they work, where they shine, where they struggle, and help you decide which one fits your use case.


1. Amazon S3 (Simple Storage Service)

Type: Object Storage (Not a traditional DB, but often used like one)

Amazon S3 is built for storing files, documents, backups, media, logs, and large datasets. It’s highly scalable and durable — often used as the foundation of modern cloud storage.

Use Cases:

  • File storage (images, videos, PDFs)
  • Backups & disaster recovery
  • Data lakes for analytics
  • Static website hosting
  • Log storage for Big Data pipelines

Pros:

  • Virtually unlimited storage
  • 99.999999999% (11 9’s) durability
  • Low cost and pay-as-you-go
  • Integrates with almost every AWS service
  • Supports versioning, lifecycle rules, encryption

Cons:

  • Not suitable for complex queries
  • No direct relational querying
  • Latency is higher compared to databases

Great for: Storing large files at scale, data lakes & archival storage.


2. Amazon DynamoDB

Type: NoSQL Key-Value / Document Database

DynamoDB is designed for applications that need ultra-fast performance and should scale automatically without managing servers.

Use Cases:

  • High-traffic web apps
  • Gaming leaderboards
  • IoT Device data
  • Serverless applications
  • Shopping carts / user sessions

Pros:

  • Fully managed (no servers)
  • Single-digit millisecond latency
  • Auto scaling with high throughput
  • Integrates well with Lambda & serverless stack
  • Global tables for multi-region apps

Cons:

  • Query patterns must be planned carefully
  • Joins and complex queries are difficult
  • Can be expensive at very high throughput

Great for: Real-time, serverless applications with massive scale.


3. Amazon RDS (Relational Database Service)

Type: SQL Relational Database

RDS supports MySQL, PostgreSQL, MariaDB, SQL Server, and Oracle. It’s best when you require structured data with relationships.

Use Cases:

  • ERP, CRM systems
  • E-commerce applications
  • Finance & transactional systems
  • Traditional business applications

Pros:

  • Managed backups, patching, scaling
  • Multi-AZ failover for high availability
  • Supports complex queries and joins
  • Familiar SQL environment

Cons:

  • Scaling vertically is limited
  • Complex joins can impact performance
  • More expensive than DynamoDB at extreme scale

Great for: Apps requiring ACID transactions & structured relational data.


4. Amazon Aurora

Type: High-performance Relational Database

Aurora is an advanced and faster version of MySQL/PostgreSQL built for cloud efficiency.

Use Cases:

  • High-traffic relational apps
  • SaaS platforms
  • Financial systems
  • Enterprise transaction apps

Pros:

  • Up to 5x faster than MySQL
  • Automatic replication to 6 copies
  • Serverless mode available
  • High availability & fault tolerance

Cons:

  • Higher cost compared to RDS
  • Overkill for small projects
  • Requires planning & configuration

Great for: Enterprise grade scalable SQL workloads.


5. Amazon Redshift

Type: Data Warehouse / Analytics Database

Redshift is built for analytical workloads — not real-time transactions.

Use Cases:

  • Business intelligence
  • Data analytics & reporting
  • ETL pipelines
  • Multi-TB/PB scale datasets

Pros:

  • Handles massive data efficiently
  • Columnar storage for fast queries
  • Integrates with BI tools like QuickSight
  • Great for analytics & dashboards

Cons:

  • Not designed for OLTP (transactional systems)
  • Needs cluster sizing & cost monitoring

Great for: Running analytical queries on huge datasets.


6. Amazon ElastiCache (Redis & Memcached)

Type: In-memory Cache Storage

Used to speed up applications by caching frequently accessed data.

Use Cases:

  • Caching API responses
  • Session storage
  • Real-time leaderboards
  • Gaming, streaming, chat apps

Pros:

  • Ultra-low latency (microseconds)
  • Reduces DB load significantly
  • Ideal for high-read workloads

Cons:

  • Data is volatile unless persisted
  • Not for primary storage
  • Needs cache strategy planning

Great for: Performance boost & real-time caching.


7. Amazon Neptune

Type: Graph Database

Perfect for storing relationships like social graphs, recommendations or network connections.

Use Cases:

  • Social networks
  • Fraud detection
  • Recommendation engines
  • Knowledge graphs

Pros:

  • Fast graph traversal
  • Supports RDF & Gremlin
  • Built for relationship-heavy data

Cons:

  • Niche use case
  • Not as common as SQL/NoSQL

Great for: Apps where relationships matter more than data rows.


8. Amazon DocumentDB

Type: Document Database (MongoDB compatible)

Used for JSON-based flexible schema data.

Use Cases:

  • Content management
  • Catalog systems
  • User profiles

Pros:

  • MongoDB API compatibility
  • Scales storage automatically
  • Great for semi-structured data

Cons:

  • Higher cost for scaling clusters
  • Not ideal for complex transactions

Great for: MongoDB workloads needing managed infrastructure.


Quick Summary (One-Liner for Each)

Service Best For Type
S3 Cheap large object/file storage Object Store
DynamoDB Fast, scalable NoSQL workloads NoSQL
RDS Traditional relational apps SQL
Aurora High-speed advanced relational apps SQL
Redshift Analytics & Data Warehousing Analytical
ElastiCache Ultra-fast caching In-memory
Neptune Relationship/graph-based systems Graph DB
DocumentDB JSON documents, MongoDB workloads Document Store

Final Short Summary

AWS offers a wide range of databases — each designed for a different purpose.
S3 stores files at scale, DynamoDB handles fast NoSQL workloads, RDS/Aurora manage traditional SQL data, Redshift powers analytics, ElastiCache boosts speed, DocumentDB stores JSON documents, and Neptune manages graph relationships.
Choosing the right one depends on your workload, structure, scaling needs, and query type.

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