Relational Database Services (RDS) and DynamoDB (NoSQL DB)

• Relational DB = SQL DB i.e. Amazon Aurora, MySQL, MariaDB, PostgreSQL, Oracle, Microsoft SQL Server
• RDS DBs = cost efficient, re-sizeable, automates time consuming admin tasks such as hardware provisioning, DB setup, patching, and backups.
• DynamoDB NoSQL DB = consistent, single digit millisecond latency at any scale. Fully managed cloud DB and supports both document and key-value store models. Great fit for mobile, web, gaming, ad tech, IoT, and many other applications with low latency needs.
• NoSQL = used when data is fluid and can change (much like JSON data)

ElastiCache and Redshift

• ElastiCache = data caching service used to help improve speed/performance of web apps
• i.e. Redis = fast, open source, in memory data store and cache & Memcached = widely adopted memory object caching system
• Redshift = Large data warehouse (DWH) DB service designed to handle petabytes of data for analysis. Simple & cost effective, use SQL to analyze your data. Uses query optimization, columnar storage on high performance local disks, and massively parallel query execution for fast queries.