Databases
Cloud Spanner
Globally distributed, strongly consistent relational database
AWS equivalent
⚠️ No direct equivalent (closest: Aurora Global)
AWS → GCP: Key Differences
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No real AWS equivalent. Aurora Global is multi-region but with eventual consistency for replicas.
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Spanner is the only database offering global ACID transactions with SQL at horizontal scale.
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This is one of GCP's genuine unique differentiators — great to mention in interviews.
Key Concepts to Know
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ACID transactions globally — traditional databases sacrifice either consistency or availability at global scale. Spanner doesn't.
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Scales horizontally: add nodes to increase throughput. 2,000 QPS per node for reads.
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True 5-nines (99.999%) availability SLA for multi-region configurations.
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Use cases: global financial systems, inventory management, gaming leaderboards, any globally distributed app needing consistent data.
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Cost: significantly higher than Cloud SQL — justify with scale and consistency requirements.
DCE Interview Tips
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Spanner is a great answer for: 'How would you design a database for a Thai bank that needs to be available across multiple regions and cannot afford inconsistent reads?'
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Mention Spanner when a customer outgrows Cloud SQL or needs multi-region writes.
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'Spanner gives you the consistency of a single database with the scale of a NoSQL system.'
Common Gotchas
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Minimum cost: ~$0.90/node/hour. For small workloads, Cloud SQL is much cheaper.
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Spanner Free Trial offers 90 days free — useful for PoCs.
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Schema changes are online (no downtime) — a genuine operational advantage.