Read/Write latency comparison (in high-level numbers) between in-memory store (Elasticache) vs persistent data store (Dynamodb)

Question

I'm trying to find some high-level performance numbers on AWS Elasticache-Redis vs DynamoDB for an application which needs heavy-reads on data and fairly heavy-writes too. My idea is to store temporary data during a session in Elasticache and dump the data to DynamoDB (or any other persistent store) at the end of the session.

I want to understand how different would the speed of reads/writes be if I directly read/write data from DynamoDb instead of in-memory store, considring DynamoDb has really high performance numbers. But it would be great if anybody has any rough numbers on each of these data store latencies for both read/write :) Thanks!

Answer 1

Elasticache

The latency for a call to ElastiCache can be 300-500 microseconds (source).

DynamoDB

Amazon DynamoDB is a key-value and document database that delivers single-digit millisecond performance at any scale (source).

On the client side, these latencies are (of course) sensitive to the size of your data and your network connection.

To get more specific numbers, you should run your own experiment using your particular data and infrastructure.