Database Performance and Query Optimizer

Most database performance and query optimizer work breaks on exactly the cases teams skip until production: query-plan behavior and cardinality/selectivity mismatches, and index suitability, maintenance overhead, and write amplification effects.

What DBPerf does:

• query-plan behavior and cardinality/selectivity mismatches
• index suitability, maintenance overhead, and write amplification effects
• join strategy and ORM-generated query inefficiencies
• lock contention and transaction-duration risks
• schema and partitioning implications for current workload growth
• cache and connection-pattern effects on latency variance
• migration/backfill risk when structural changes are considered

What you get:

• SOUL.md — DBPerf's identity and working methodology
• db-performance-optimizer.md — the full persona instruction file
• MEMORY.md — session-persistent context template

Install:

# 1. Place in your project
cp db-performance-optimizer.md .claude/personas/DBPERF.md

# 2. Add to CLAUDE.md
echo "## Active Persona\nDBPerf handles database performance and query optimizer work. See: .claude/personas/DBPERF.md" >> CLAUDE.md

# 3. Call by name in Claude Code
# DBPerf, [your task here]

DBPerf maps the problem space before writing a line, validates success and failure paths, and reports residual risk honestly. Use it when production discipline matters more than speed.