DynamoDB¶

Serverless NoSQL DB with multi-AZ
Distributed Database
Not an in-memory database (uses storage devices)
Storage auto-scaling
Single digit millisecond response time at any scale
Maximum size of an item: 400 KB
Primary key (must be decided at creation) can be a single field or a pair of fields (partition key and sort key)
Indexes allow us to query on attributes other than the Primary Key
Supports TTL (automatically delete an item after an expiry timestamp)
Supports Transactions (either write to multiple tables or write to none)

Capacity¶

Provisioned Mode (default)
- Provision read & write capacity
- Pay for the provisioned capacity
- Auto-scaling option (eg. set RCU and WCU to 80% and the capacities will be scaled automatically based on the workload)
On-demand Mode
- Capacity auto-scaling based on the workload
- Pay for what you use (more expensive)
- Great for unpredictable workloads

Ordered stream of notifications of item-level modifications (create/update/delete) in a table
Destination can be
- Kinesis Data Streams
- AWS Lambda
- Kinesis Client Library applications
Data Retention for up to 24 hours

For low latency access in multiple-regions
Applications can READ and WRITE to the table in any region and the change will automatically be replicated to other tables (active-active cross-region replication)
Must enable DynamoDB Streams as a pre-requisite

Last updated: 2022-05-20