Five Whys Builder

# 5 Whys Analysis
Date: 2026-06-09

## Problem
The API returned 500 errors for 15 minutes

## Why Analysis

**Why 1:** The database connection pool was exhausted
**Why 2:** A slow query was holding connections for 30+ seconds
**Why 3:** A missing index caused a full table scan on 10M rows
**Why 4:** The index was dropped during a schema migration
**Why 5:** The migration script was not reviewed for index changes

## Root Cause
The migration script was not reviewed for index changes

## Corrective Action
Add index review checklist to migration PR template

## Follow-up
- [ ] Implement: Add index review checklist to migration PR template
- [ ] Verify fix in production
- [ ] Update runbook / post-mortem