sql-optimization-patterns

Iron Law

PROFILE BEFORE OPTIMIZING — RUN EXPLAIN (ANALYZE, BUFFERS) ON THE ACTUAL SLOW QUERY BEFORE WRITING A SINGLE INDEX

When to Use This Skill

• Debugging slow-running queries in PostgreSQL
• Endpoint response times exceeding target SLA
• Designing performant database schemas for high-traffic tables
• Reducing database load and infrastructure costs
• Resolving N+1 query problems from ORM usage (SQLAlchemy, Prisma, R2DBC)
• Analyzing EXPLAIN query plans from production
• Implementing efficient composite and partial indexes
• Migrating from OFFSET pagination to cursor-based pagination

Do Not Use This Skill When

• You need cloud-native SQL or analytics platforms (BigQuery, Snowflake) — use sql-pro
• You need schema migration design — use database-schema-designer
• The database is not PostgreSQL (patterns are PostgreSQL-specific)