Databases
Cloud SQL
Fully managed relational database service
AWS equivalent
RDS
AWS → GCP: Key Differences
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Very similar to RDS. Supports MySQL, PostgreSQL, and SQL Server.
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High availability: standby replica in another zone with automatic failover. ≈ RDS Multi-AZ.
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Cloud SQL Auth Proxy: secure connection to Cloud SQL without managing SSL certs or whitelisting IPs.
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No Oracle support. For Oracle migrations, use Bare Metal Solution or consider refactoring.
Key Concepts to Know
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Automated backups, point-in-time recovery (PITR) — same concepts as RDS.
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Storage auto-increase: Cloud SQL can automatically grow storage. Doesn't auto-shrink.
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Private IP: connect from within VPC without public internet.
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Database Migration Service: migrate from on-prem MySQL/PostgreSQL to Cloud SQL with minimal downtime using CDC.
DCE Interview Tips
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For Thai banks migrating from on-prem MySQL: 'Cloud SQL is a direct lift with minimal changes. Use Database Migration Service for online migration with near-zero downtime.'
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HA is not enabled by default — important to mention for production workloads.
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Cloud SQL vs Spanner: 'Cloud SQL for existing relational workloads under ~10TB. Spanner when you need horizontal scaling and global consistency.'
Common Gotchas
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Cloud SQL is zonal by default. You must explicitly enable HA for production — this doubles the cost.
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Cloud SQL instances don't survive region failures — only zone failures with HA. For true multi-region, consider Spanner.
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Max storage: 64TB. Beyond that, you need Spanner or BigQuery.