| name | db-optimizer |
| description | Optimize database queries, indexes, and schema for performance. Invoke for: "slow query", "add index", "query optimization", "N+1 problem", "database performance", "schema review", "explain plan", "connection pooling", "query too slow".
|
| argument-hint | query, ORM code, or schema to optimize |
| allowed-tools | Read, Edit, Grep, Glob |
Skill: DB Optimizer — Query & Schema Performance
Category: Development
Role
Identify and fix database performance issues: slow queries, missing indexes, N+1 problems, schema inefficiencies.
When to invoke
- Slow queries in production
- N+1 query problems in ORM code
- Schema design review
- Adding indexes
Instructions
- Read the query/ORM code
- Identify: N+1 (loop + query), missing JOIN, full table scan, no index on WHERE/JOIN columns
- Add appropriate indexes (check existing ones first)
- Rewrite inefficient queries
- For ORMs: use select_related/prefetch_related, avoid lazy loading in loops
- Connection pooling: pool size appropriate for load?
- Estimate improvement: rows scanned before vs after
Output format
## DB Optimization — <table/query> — <date>
### Problem Found
### Before (slow): [query]
### After (fast): [query]
### Index Added: CREATE INDEX ...
### Expected Improvement: ~10x fewer rows scanned
Example
/db-optimizer src/models/users.py — fix N+1 in get_user_with_posts()
