Upgrade Paths for PostgreSQL and Cloud SQL Users on GCP: Choosing Between CockroachDB and Cloud Spanner
If you’re running PostgreSQL or Cloud SQL on Google Cloud Platform (GCP) and looking to scale beyond what these can offer, you might be wondering — what’s next? How do you handle high availability, global scaling, and big workloads without breaking the bank or your app?
In this article, I’ll share my findings comparing CockroachDB and Google Cloud Spanner as upgrade paths. This is part of my learning journey for the Google Cloud Professional Cloud Architect (PCA) certification — so you get real insights backed by hands-on testing and research.
Why Look Beyond PostgreSQL and Cloud SQL?
PostgreSQL is amazing — battle-tested, reliable, and feature-rich. Cloud SQL on GCP simplifies management but can hit limits when:
Your app demands higher throughput (think hundreds or thousands of requests per second)
You want global data distribution with strong consistency
You want automated failover without writing custom retry logic
You want seamless horizontal scaling
This is where distributed SQL databases like CockroachDB and Cloud Spanner come into play.
CockroachDB vs Google Cloud Spanner — The Quick Rundown
| Feature | CockroachDB | Google Cloud Spanner |
| Open Source? | Yes (Core) + Enterprise options | No, fully managed proprietary |
| Deployment | Self-host or managed service | Fully managed GCP service only |
| Failover Handling | You handle it in your app logic | Fully automated by Google |
| Global Distribution | Supported with manual config | Built-in, global, strongly consistent |
| SQL Compatibility | PostgreSQL wire protocol compatible | ANSI SQL standard |
| Scaling | Horizontal, manual node management | Transparent scaling via nodes |
| Pricing (Mumbai, ~3 nodes + storage) | ~$500/month | ~$615/month |
Developer Perspective: Failover and High Availability
This is important:
With CockroachDB, the cluster replicates data across nodes, but your app has to detect node failures and retry transactions accordingly. This adds complexity but gives you control.
With Cloud Spanner, Google handles all that automatically. Your app talks to a single endpoint; Google transparently manages failover and load balancing.
When Should You Pick Which?
Go with CockroachDB if:
You want an open-source solution you can host anywhere.
You don’t mind managing cluster nodes and failover logic.
PostgreSQL compatibility is a must.
You want flexibility across clouds or on-prem.
Go with Cloud Spanner if:
You want zero operational headaches — fully managed.
You need strong SLAs and global consistency out of the box.
Automatic failover and scaling are top priorities.
You’re already invested in the Google Cloud ecosystem.
Wrapping Up
Both CockroachDB and Cloud Spanner offer powerful paths beyond PostgreSQL and Cloud SQL on GCP — but with different tradeoffs.
CockroachDB offers more control and flexibility, especially if you want to self-host or stay open source. Cloud Spanner shines when you want simplicity, reliability, and global scale with minimal ops.
I’m sharing this as part of my hands-on learning for the Google Cloud Professional Cloud Architect certification — trying out these tools to get a real feel for what they offer.
If you want me to share scripts or benchmarks I ran, or need help with migration tips, just drop a comment or ping me!