If your app needs 25 items of 13KB per second with strongly consistent reads, what should the throughput be set to?

To determine the required throughput for an application that needs to read 25 items of 13KB each per second with strongly consistent reads, it is essential to understand how AWS services like DynamoDB measure throughput and the implications of strong consistency.

In AWS DynamoDB, a strongly consistent read operation consumes double the read capacity units (RCUs) compared to an eventually consistent read operation. Each read capacity unit allows you to read one strongly consistent item of up to 4KB in size. To calculate the required throughput in a context where 25 items of 13KB are needed each second, follow this process:

1. Calculate the size of a single item: Each item requires 13KB.
2. Determine the number of read operations needed: You need to read 25 items per second.
3. Determine the RCUs required for one item: Each item is 13KB, which exceeds the 4KB limit for one RCU. To find the RCUs needed for one item, divide the item size by the RCU capacity:
   13KB / 4KB = 3.25. Since you can’t have a fraction of a read capacity unit, round this up to 4 RCUs