Google Cloud SQL: Managed Postgres/MySQL, HA & Auth Proxy

Google Cloud SQL

Cloud SQL is Google Cloud's managed relational database service for PostgreSQL, MySQL, and SQL Server. Like other managed offerings, it removes the operational burden — provisioning, patching, backups, replication, and failover — while you keep a familiar SQL engine.

It's the sensible default on GCP when you want a relational database without operating it yourself. The connectivity model is the part worth learning early: prefer private IP and the Cloud SQL Auth Proxy over exposing the database to the internet.

TL;DR

Managed PostgreSQL / MySQL / SQL Server with backups, HA, and replicas.
Connect via private IP and the Cloud SQL Auth Proxy — avoid public exposure.
Enable HA (regional) and point-in-time recovery; test restores.
Pool connections, especially from serverless (Cloud Functions/Run).

Quick Example

Create a highly available Postgres instance in one command — REGIONAL gives automatic failover:

Core Concepts

Managed instances — automated patching within maintenance windows.
Backups & PITR — scheduled backups and point-in-time recovery (engine-dependent).
High availability — regional configuration with a failover replica.
Read replicas — offload reads (engine/region dependent).

Connectivity

Choose how apps reach the database — production should avoid the public internet:

Best Practices

Use private connectivity for internal services; treat the Auth Proxy/connector as the standard path.
Enable backups and point-in-time recovery; periodically test restores.
Pick a low-traffic maintenance window; plan major-version upgrades like a migration.
Pool connections (serverless clients exhaust limits fast); co-locate app and database in the same region to avoid latency.

Common Mistakes

Exposing the database publicly

Cross-region latency

FAQ

Cloud SQL or AWS RDS?

They're close equivalents on their respective clouds — both manage Postgres/MySQL (Cloud SQL also runs SQL Server). Choose based on where the rest of your stack lives. On GCP, Cloud SQL integrates with VPC, IAM, and monitoring; on AWS, RDS does the same.

How should I connect to Cloud SQL securely?

Use private IP within your VPC and the Cloud SQL Auth Proxy (or language connectors), which handle IAM-based auth and TLS for you. Avoid public IP with broad authorized networks unless you genuinely need it.

Is high availability a substitute for backups?

No. HA (a regional failover replica) protects against instance/zone failure, but it faithfully replicates mistakes like a bad DELETE or migration. You still need backups and point-in-time recovery — and you must test that you can restore them.

Why do my serverless functions exhaust connections?

Each function instance can open its own connection, and they scale out quickly, overrunning the instance's connection limit. Use connection pooling (and short-lived connections), and consider the Auth Proxy's pooling guidance for serverless.