21. Databases in AWS

Question 1

Database Types

Answer 1

• RDBMS (= SQL/OLTP): RDS, Aurora, great for joins
• NoSQL databases - no joins, no SQL (DynamoDB(JSON), ElastiCache (key/value pairs), Neptune(graphs), DocumentDB(for Mongo), Keyspaces(for Apache Cassandra)
• Object Store: S3 (for big object) / Glacier (for backups / archives)
• Data Warehouse (= SQL Analytics / BI): Redshift (OLAP), Athena, EMR
• Search: OpenSearch (JSON) - free text, unstructured searches
• Graphs: Amazon Neptune - displays relationships between data
• Ledger: Amazon Quantum Ledger Database
• Time series: Amazon Timestream

Question 2

RDS

Answer 2

• Managed PostgreSQL / MySQL / Oracle / SQL Server / MariaDB / Custom
• Provisioned RDS Instance Size and EBS Volume Type & Size
• Auto-scaling capability for Storage
• Support for Read Replicas and Multi AZ
• Security through IAM, Security Groups, KMS, SSL in transit
• Automated backup with Point in time restore feature
• Manual DB Snapshot for longer-term recovery
• Managed and Scheduled maintenance

Question 3

Use cases RDS

Answer 3

• Store relational datasets (RDBMS / OLTP), perform SQL queries, transactions

Question 4

ElastiCache

Answer 4

• Managed Redis/Memcached (similar offering as RDS, but for caches)
• In-memory data store, sub-millisecond latency
• Select and ElastiCache instance type (e.g, cache.m6g.large)
• Support for clustering (Redis) and Multi, AZ, ReadReplicas (sharding)
• Security through IAM, Security Groups, KMS, Redis Auth
• Backup/Snapshot/Point in time restore feature
• Managed and Scheduled maintenance
• Requires some application code changes to be laveraged.