4144. AWS-Database-DynamoDBAWS and DynamoDB
Use DynamoDB as NoSQL database.
1.1 What Is DynamoDB?
Amazon DynamoDB is a fast and flexible NoSQL database service for all applications that need consistent, single-digit millisecond latency at any scale. It is a fully managed database and supports both document and key-value data models. Its flexible data model and reliable performance make it a great fit for mobile, web, gaming, ad-tech, loT, and many other applications.
1.2 Basics of DynamoDB
- Stored on SSD storage
- Spread across 3 geographically distinct data centers
- Eventual Consistent Reads (Default)
- Strongly Consistent Reads
1.3 Consistency Model of DynamoDB
When reading data from DynamoDB, users can specify whether they want the read to be eventually consistent or strongly consistent:
Eventually consistent reads (the default)– The eventual consistency option maximizes the read throughput. However, an eventually consistent read might not reflect the results of a recently completed write. All copies of data usually reach consistency within a second. Repeating a read after a short time should return the updated data.
Strongly consistent reads— A strongly consistent read returns a result that reflects all writes that received a successful response before the read.
ACID transactions– DynamoDB transactions provide developers atomicity, consistency, isolation, and durability (ACID) across one or more tables within a single AWS account and region. You can use transactions when building applications that require coordinated inserts, deletes, or updates to multiple items as part of a single logical business operation.