Cloud SQL Core Concepts
Cloud SQL provides managed relational databases, abstracting the underlying infrastructure while offering standard database engines.
Supported Engines
Cloud SQL supports the following database engines (see supported versions):
MySQL: Versions 5.6, 5.7, 8.0, and 8.4.
PostgreSQL: Versions 9.6, 10, 11, 12, 13, 14, 15, 16, 17, and 18 (default).
SQL Server: 2017 (Express, Web, Standard, Enterprise), 2019, 2022, and 2025 (Express, Enterprise, Standard).
Instance Architecture
Each Cloud SQL instance is powered by a virtual machine (VM) running the database program.
Primary Instance: The main read/write connection point.
High Availability (HA): Provides a standby VM in a different zone with automatic failover.
Read Replicas: Used to scale read traffic and provide local access in different regions.
Storage and Networking
Persistent Disk: Scalable and durable network storage attached to the VM.
Connectivity: Supports Private IP (using VPC peering for MySQL and PostgreSQL only; or using private services access or Private Service Connect for all Cloud SQL engines) and Public IP (with authorized networks or Auth Proxy).
Pricing
Cloud SQL pricing is based on:
Instance Type: vCPUs and RAM.
Storage: Amount of data stored and IOPS.
Networking: Network egress and IP address usage.
DNS pricing: Charge is per zone per month (regardless of whether you use your zone). You also pay for queries against your zones.
Licensing: Applies to SQL Server only. In addition to instance and resource pricing, SQL Server also has a licensing component. High availability, or regional instances, will only incur the cost for a single license for the active resource. As a managed service, Cloud SQL does not support BYOL (Bring your own license).
For the latest pricing, visit: Cloud SQL Pricing.