aws serverless dynamodb dynamo
DynamoDB
Serverless NoSQL provided by AWS
- max size of an item: 400kb
- Use case: for rapidly evolving database schemas.
R/W Capacity Modes
- Provisioned Mode: Good for prod with auto scaling capacity
- On-demand: R/W is auto scaled, for un-predictable workload, steep sudden spikes
DynamoDB Accerelator (DAX)
| DAX | Redis |
|---|---|
| Cache simple object, for query and scan the cache | Can cache aggregated result |
DynamoDB Stream Processing Feature
It’s the ordered streaming of modifications of items in DynamoDB. So we can use this feature to react for changes on it. Use cases:
- React to changes (Realtime)
- Trigger something by using Lambda
- Cross region replication | DynamoDB Streaming | Kinesis Data Stream (Newer) | | -------------------------------------------------- | --------------------------- | | 24 hour retention | 1 year retention | | Limited number of consumers | Higher consumers | | Can process by using Lambda/Stream Kinesis Adapter | More integrations |
DynamoDB Global
- Allow to replicate data to multi region
- R/W to any replica in any region
- Must enable DynamoDB Stream as a pre-requisite, because database operations must be enforced in orders.
DynamoDB TTL
- Delete items after a time.
- Use cases: user sessions, reduce stored data, …
DynamoDB Backup and Recovery
- Continuous backup with PITR: 35 days, optional enabled.
- On-demand backup: Long term retention
- E/I with S3: Must enable PITR for exposing to S3 and importing to DynamoDB