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DynamoDb Read Capacity Units - RCU

1. DynamoDb Max Item Size is 400KB

2. 1 RCU is ~1 Read request from the DB

3. Why is it only roughly 1 read request because we could have multiple types of read requests

4. We could have a consistent read request

5. We could have an eventual consistent read request

6. We could have a transactional read request

4. If the item we read is up to 4kb and we read with eventual consistent than we could actual make 2 such items read with 1 RCU

5. If the item i up to 8KB and we make an eventual consistent read than we could have a single read request per second with 1 RCU

6. If the item is larger than 4KB and we want to perform a consistent read request than this would require 2 read request at least.

7. If we need a transactional read request for an item up to 8KB then we would need even 4 RCU

8. If we need a transactional read request for an item up to 4KB then we would need 2 RCU that is because transactional read requires 2 phase commit the first RCU would be for prepare and the second would be for the actual write.


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