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How DynamoDB Read and Write Capacity Units Work
Understanding how these capacity units work is essential for optimizing performance and cost.
Read and Write capacity units or RCUs and WCUs are DynamoDB’s currency.
They are used to measure the core element of your table costs.
As opposed to many other NoSQL databases, DynamoDB uses read and write throughput as the main pricing model (besides for storage costs).
Your job as a DynamoDB developer is to learn how to optimize this currency to be able to efficiently query your database while using using up as little capacity units as possible.
There are a variety of ways to optimize this currency and it all starts with understanding how these capacity units are calculated in DynamoDB.
Let’s start by understanding read capacity units and then write capacity units.
Read Capacity Units (RCUs)
DynamoDB measures read operations with read capacity units which determine how much data you can read per second.
Each RCU represents one strongly consistent read request per second for an item up to 4KB in size, or two eventually consistent reads per second.
