DynamoDB

• Managed database, replicated across 3 AZ
• NoSQL database
• Enable event driven programming using DynamoDB Streams
• In DynamoDB database is already created, only needs to create Table
• Each Table should have a primary key (Must be decided while creating the table)
• Can have infinite number of rows
• Max size of item can be 400KB
• Data types
• Scalar
  • String
  • Number
  • Binary
  • Boolean
  • Null
• Document
  • List
  • Map
• Set
  • String Set
  • Number Set
  • Binary Set
• To improve performance we can use
• DAX (mili seconds to micro seconds)
• Use partition keys of high cardinality, so large number of distinct values for each item
• DAX
• Stands for DynamoDB Accelerator
• Caching mechanism for DynamoDB
• DynamoDB Stream
• Raise event on Create, Update, Delete
• Can be used to trigger events on DB Changes
• Transaction
• All or nothing of operations
• Global Table
• Replicated in multiple region
• Needs to enable DynamoDB Stream
• Active Active Replication
  • Changes in any region, impact all other regions
• Security
• Available in VPC Endpoints
• Fully controlled by IAM
• Encryption
  • At rest by KMS
  • In flight by SSL/TLS

Provisioned Throughput

• 2 types of Provision Throughput
• RCU
  • Read Capacity Unit
  • Each RCU can handle one of the followings
  • 1 Strongly Consistent read 4KB/s
  • 2 Eventually Consistent read 4KB/s
• WCU
  • Write Capacity Unit
  • 1 write 1KB/s
• Can be used on-demand throughput (price is 2.5X more)
• Throughput can be exceeded using Burst Credit
• If Burst Credit is empty, it throws ProvisionThroughputException
• In case of ProvisionThroughputException, it is recommended to retry
• Can be used DynamoDB Auto Scaling
• No need to provision throughput
• Comparatively expensive