Question: When to use ElastiCache vs DynamoDB?


Amazon Elasticache and Amazon DynamoDB are two of the most popular managed services offered by AWS. Although both services aim to enhance application performance, they cater to different scenarios based on your specific needs.

Amazon Elasticache

Amazon ElastiCache is a fully-managed, in-memory cache service that supports two open-source in-memory caching engines: Redis and Memcached. It works by storing frequently accessed data in memory, thereby speeding up the retrieval process and improving the overall performance of web applications.

ElastiCache excels in situations where data is read more often than it's written, like social media platforms, e-commerce websites, and gaming applications. It reduces latency and increases throughput by diminishing the number of requests made to a database or backend service.

Consider using ElastiCache when:

  • You need to cache repetitive data to boost application speed.
  • You want to alleviate the pressure on a backend database.
  • You have stateless applications that require session data storage.

Amazon DynamoDB

Amazon DynamoDB, on the other hand, is a fully-managed NoSQL database service that promises quick and predictable performance with effortless scalability. It's capable of managing varying types of data and can effortlessly scale from a handful of requests per second to millions.

DynamoDB thrives in environments with balanced or write-heavy workloads, such as mobile applications, ad-tech platforms, and IoT devices. It offers a flexible data model for storing and querying semi-structured data at scale.

Consider using DynamoDB when:

  • You need to store and process large volumes of semi-structured data.
  • Your use case demands high-speed read and write operations.
  • You're building real-time applications that necessitate low-latency access to data.

In summary, you should choose Amazon ElastiCache when data-read operations predominate, and caching frequently accessed data directly in memory would greatly improve the response time and overall performance of your application. Conversely, Amazon DynamoDB is the preferable option when you need a flexible and scalable NoSQL database to efficiently handle both high-volume data storage and high-speed read/write operations. Weighing these factors should guide you in making an informed decision between ElastiCache and DynamoDB.

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