Scan with Phone

Scan to instantly open and share this page on your mobile device.

Link copied to clipboard!

Group 6: Relational Databases

Managed relational database services: Cloud SQL (managed MySQL/PostgreSQL/SQL Server), AlloyDB (PostgreSQL-compatible), Spanner (globally distributed), Database Migration Service (migration tool). Choose based on scale requirements, consistency needs, and geographical distribution.

Scale & Consistency Spectrum: Cloud SQL for regional applications; AlloyDB for analytical workloads; Spanner for global applications requiring strong consistency; use Database Migration Service for seamless database moves.

Services & Core Identity

Cloud SQL

Fully managed MySQL, PostgreSQL, and SQL Server with automated backups, scaling, and high availability.

AlloyDB

PostgreSQL-compatible database optimized for analytical and transactional workloads with columnar engine.

Cloud Spanner

Globally distributed, horizontally scalable database combining SQL semantics with NoSQL scale.

Database Migration Service

Serverless migration service supporting continuous replication with minimal downtime.

Key Differences

DimensionCloud SQLAlloyDBCloud SpannerDatabase Migration Service
Scale LimitRegional scaleHigh performanceGlobal scaleMigration tool
ConsistencyStrong (regional)Strong (regional)Strong (global)N/A
Use CaseTraditional appsAnalytics + OLTPGlobal applicationsDatabase migration
SQL CompatibilityMySQL/PostgreSQL/SQL ServerPostgreSQLGoogle SQL (ANSI-like)Source dependent
PerformanceStandardHigh (columnar)Horizontal scaleMigration focused
Cost ModelInstance-basedInstance + storageProcessing + storageMigration duration

Mathematical Selection Model

Criteria [0..10]. Higher scores indicate better database fit.

Score_CloudSQL = 0.30*C_traditionalSqlApp + 0.25*C_operationalSimplicity + 0.20*C_costSensitivity + 0.15*(10 - C_globalDistribution) + 0.10*C_compatibility Score_AlloyDB = 0.30*C_analyticalWorkload + 0.25*C_highPerformance + 0.20*C_postgresCompatibility + 0.15*C_columnarEngine + 0.10*(10 - C_globalDistribution) Score_CloudSpanner = 0.35*C_globalDistribution + 0.25*C_strongConsistency + 0.20*C_horizontalScale + 0.15*C_highAvailability + 0.05*(10 - C_costSensitivity) Score_DatabaseMigration = 0.40*C_migrationNeed + 0.30*C_minimumDowntime + 0.20*C_continuousReplication + 0.10*C_heterogeneousMigration
{{s.name}}: {{s.val | number:2}}

Interpretation Rules

  • Cloud SQL: Web applications, content management, e-commerce, regional business applications
  • AlloyDB: Data warehousing, real-time analytics, hybrid OLTP/OLAP workloads
  • Cloud Spanner: Global financial systems, gaming backends, multi-region applications
  • Database Migration Service: Moving from on-premises or other clouds with minimal disruption

When NOT to Use Relational Databases

  • Simple key-value storage (consider Firestore or Bigtable)
  • Document-oriented data (consider Firestore)
  • Massive unstructured data analytics (consider BigQuery)
  • High-frequency trading requiring microsecond latency (consider specialized solutions)

Summary

GCP relational databases provide managed solutions from regional to global scale. Cloud SQL serves traditional applications, AlloyDB optimizes for analytics performance, Cloud Spanner enables global consistency, and Database Migration Service facilitates seamless transitions. Choose based on geographical requirements, consistency needs, and performance characteristics.

next