Operating

• Every operation in dynamodb consumes atleast 1 RCU or WCU
• Every table has a burst pool of 300 seconds for WCU & RCU

Query Operation

• Query operation will always involved a Partition Key and optionally a Sort Key
• One can choose to retriev specific attributes of an item, but you are charged RCU of entire item

Scan Operation

• This can be used to search based on any attribute value
• The operation consumes capacity of all items that are scanned

Consistency Models

• DynamoDB supports 2 models a. Eventual Consistency b. Strong Consistency
• In DynamoDB every data is replicated in various AZs across multiple storage nodes
• One of the nodes is chosen as Leader Node. All writes happen to Leader Node
• While 1 RCU = 4KB/s for Strongly Consistent reads , 1 RCU = 8KB/S for eventually consistent read.