Cloud SQL and Cloud Spanner

GCP offers a comprehensive range of managed database services. This lesson covers the two most important relational options: Cloud SQL for traditional relational workloads and Cloud Spanner for globally distributed relational databases that need unlimited scale.

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Cloud SQL

Cloud SQL is a fully managed relational database service. It handles provisioning, replication, backups, patching, and failover so you can focus on your application.

Supported Engines

Engine	Versions
MySQL	5.7, 8.0
PostgreSQL	12, 13, 14, 15, 16
SQL Server	2017, 2019, 2022

Key Features

Automatic Backups

• Automated daily backups with configurable retention (1–365 days)
• On-demand backups that persist until you delete them
• Point-in-time recovery — restore to any second within the retention window

High Availability

Cloud SQL HA uses a regional configuration with a primary instance and a standby replica in a different zone:

Primary Instance (Zone A) ←— synchronous replication —→ Standby (Zone B)

• Automatic failover if the primary zone fails (typically 60–120 seconds)
• The standby is not used for read traffic — it's purely for failover
• HA instances cost approximately double the base price

Read Replicas

Scale read-heavy workloads by creating read replicas:

• Up to 10 read replicas per primary instance
• Cross-region read replicas are supported
• Replication is asynchronous
• Replicas can be promoted to standalone instances

Scaling

Dimension	Capability
Vertical	Up to 96 vCPUs, 624 GB RAM
Storage	Up to 64 TB, auto-increase available
Read scaling	Up to 10 read replicas

Security

• Encryption at rest — enabled by default (AES-256)
• Encryption in transit — SSL/TLS connections
• Private IP — connect via VPC without exposing to the public internet
• IAM database authentication — use IAM accounts for PostgreSQL and MySQL
• Cloud SQL Auth Proxy — secure, encrypted tunnel to your instance

Creating a Cloud SQL Instance

gcloud sql instances create my-db \
  --database-version=POSTGRES_16 \
  --tier=db-custom-2-8192 \
  --region=europe-west2 \
  --availability-type=REGIONAL \
  --storage-auto-increase

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Cloud Spanner

Cloud Spanner is a globally distributed, horizontally scalable relational database. It combines the structure of a traditional relational database with the scale of a NoSQL system.

Key Differentiators