---
title: "2025-04-07 - Cache Invalidation Bug in analytics-pipeline"
date: 2025-04-07
severity: P3
services: [analytics-pipeline, notification-service, inventory-api]
tags: [rca, p3, application]
status: resolved
duration_minutes: 56
author: DevOps
---
# 2025-04-07 - Cache Invalidation Bug in analytics-pipeline
## Summary
On 2025-04-07, the analytics-pipeline service experienced a cache invalidation bug. The incident lasted approximately 56 minutes and affected 581 users and 3 dependent services.
## Timeline
| Time (UTC) | Event |
|------------|-------|
| 16:47 | Monitoring alert triggered |
| 16:49 | On-call engineer paged |
| 16:52 | Initial investigation started |
| 16:57 | Root cause identified |
| 17:20 | Mitigation applied |
| 17:31 | Service recovery observed |
| 17:43 | Incident resolved |
## Root Cause
The incident was caused by cache invalidation bug in the analytics-pipeline service.
Investigation revealed multiple contributing factors:
1. Recent code changes introduced a regression
2. Test coverage did not include edge cases
3. Monitoring gaps delayed detection
## Impact
- Service degradation: 82% of requests affected
- Error rate spike: 13% (baseline: <1%)
- Latency increase: p99 went from 188ms to 7315ms
### Affected Services
- analytics-pipeline
- notification-service
- inventory-api
### Customer Impact
- 1579 customer-facing errors
- 53 support tickets created
- Estimated revenue impact: $8838
## Resolution
1. Deployed hotfix to address the immediate issue
2. Added regression tests for the affected code path
3. Implemented additional monitoring and alerting
4. Updated runbook with troubleshooting steps
## Lessons Learned
### What Went Well
- Alert fired within 3 minutes of incident start
- On-call response was quick (6 minutes)
- Cross-team collaboration was effective
- Communication to stakeholders was timely
### What Could Be Improved
- Need better runbooks for application issues
- Monitoring coverage gaps identified
- Load testing should cover this scenario
- Need automated rollback for faster recovery
## Action Items
| Priority | Action | Owner | Due Date |
|----------|--------|-------|----------|
| P1 | Implement monitoring for cache invalidation bug | Platform Engineering | 2025-04-14 |
| P2 | Update runbook | Database Team | 2025-04-21 |
| P2 | Add load test scenario | Backend Team | 2025-04-28 |
| P3 | Review similar services | Backend Team | 2025-05-07 |
## Related Incidents
- [[2025-04-07-previous-incident|Previous application incident]]
- [[runbook-analytics-pipeline|analytics-pipeline Runbook]]
- [[architecture-application|Application Architecture]]
---
*RCA prepared by DevOps on 2025-04-10*
