Query Optimization Checklist for Agent-Generated SQL

AI agents generate syntactically correct SQL that is often performance-catastrophic. Before executing any agent-generated query:

1. Check for missing indexes: EXPLAIN ANALYZE every query. Look for sequential scans on tables >10K rows. 2. Check for N+1 patterns: Agent often generates loops with individual queries. Batch into JOINs or CTEs. 3. Check for SELECT *: Replace with explicit column lists. Reduces I/O by 30-80%. 4. Check for unbounded queries: Always add LIMIT. Agent-generated queries without limits can return millions of rows. 5. Check for implicit type casting: WHERE varchar_col = 123 kills index usage.

We automated this checklist as a pre-execution validator. Query timeouts dropped by 85%.