PostgreSQL vs MySQL in 2026: Performance, Cost, and When to Switch

PostgreSQL vs MySQL in 2026

Two threads went viral on r/PostgreSQL recently. One: “$480K/year saved by switching from MySQL to Postgres” (51 upvotes). The other: “You just need Postgres” (264 upvotes).

The $480K Cost Angle

MySQL Enterprise Edition costs thousands per server per year
Amazon RDS for MySQL charges a premium for Multi-AZ
PostgreSQL is fully open source under the PostgreSQL License
Managed PostgreSQL (Supabase, Neon, Railway) has aggressively competitive pricing

Performance Comparison

Read-Heavy OLTP

MySQL has a slight edge in simple, high-concurrency reads. This advantage has narrowed.

Write-Heavy and Mixed

PostgreSQL’s MVCC handles write-heavy workloads with fewer lock contention issues.

Complex Queries

PostgreSQL’s query planner is more sophisticated. Lateral joins, recursive CTEs, and partial indexes.

Feature Comparison Table

Feature	PostgreSQL	MySQL
JSON support	JSONB (binary, indexed)	JSON (text-based)
Window functions	Full support, mature	Since 8.0, less optimized
CTEs	Full recursive, materialization control	Since 8.0, no CYCLE/SEARCH
Full-text search	Built-in tsvector, ranking	FULLTEXT index, basic
Extensions	PostGIS, pgvector, TimescaleDB	Limited
Licensing	PostgreSQL License (permissive)	GPL / Commercial

When MySQL Is Still Right

Already on PlanetScale
ORM or framework is MySQL-optimized
Maximum simple read throughput
Team’s DBA expertise is MySQL-centric

Migration: What the Real Work Looks Like

Schema conversion: TINYINT(1) to BOOLEAN, AUTO_INCREMENT to SERIAL
SQL dialect: GROUP_CONCAT to STRING_AGG, LIMIT x,y to LIMIT y OFFSET x
Application layer: ORM config, raw SQL review

AI2SQL supports both PostgreSQL and MySQL dialects for easy switching.

pgvector Changes the Calculation

AI-native applications need vector storage. PostgreSQL has pgvector. MySQL has no equivalent. Teams building AI features choose PostgreSQL by default.

Verdict

New projects: PostgreSQL. Existing MySQL: evaluate if you are on Enterprise licensing or need JSON/vector. For analytics: PostgreSQL wins clearly.

AI2SQL generates dialect-aware SQL for both databases.

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