DynamoDB

DynamoDB is a NoSQL fully managed Database-as-a-Service (DBaaS) product available within AWS.

Tables

On-Demand Backups

Point-in-time Recovery (PITR)

Considerations

Operations, Consistency and Performance

Read and Writing

Query

Scan

Consistency Model

WCU Calculation

RCU Calculation

Indexes (LSI and GSI)

Local Secondary Indexes (LSI) and Global Secondary Indexes (GSI) allow for an alternative presentation of data stored in a base table.

LSI allow for alternative SK's whereas with GSIs you can use alternative PK and SK.

Local Secondary Indexes (LSI)

Global Secondary Indexes (GSI)

LSI and GSI Considerations

Streams and Triggers

DynamoDB Streams are a 24 hour rolling window of time ordered changes to ITEMS in a DynamoDB table

Streams have to be enabled on a per table basis , and have 4 view types

KEYS_ONLY

NEW_IMAGE

OLD_IMAGE

NEW_AND_OLD_IMAGES

Lambda can be integrated to provide trigger functionality - invoking when new entries are added on the stream.

DynamoDB Accelerator (DAX)

DynamoDB Accelerator (DAX) is an in-memory cache designed specifically for DynamoDB. It should be your default choice for any DynamoDB caching related questions.

Traditional Caches vs DAX

Global Tables

DynamoDB Global Tables provides multi-master global replication of DynamoDB tables which can be used for performance, HA or DR/BC reasons.

Time-To-Live (TTL)

Amazon DynamoDB Time to Live (TTL) allows you to define a per-item timestamp to determine when an item is no longer needed.

Shortly after the date and time of the specified timestamp, DynamoDB deletes the item from your table without consuming any write throughput.

TTL is provided at no extra cost as a means to reduce stored data volumes by retaining only the items that remain current for your workload’s needs