# Redis Cache Migration - Complete Documentation Index

**Project:** Multi-Category VideoMedia Support  
**Created:** December 10, 2025  
**Status:** Ready for Implementation

---

## 📚 Documentation Overview

Five comprehensive documents have been created to guide the Redis cache migration:

### 1. **REDIS_CACHE_SUMMARY.md** (Executive Summary)

- **Purpose:** High-level overview for decision makers and team leads
- **Length:** ~300 lines
- **Contains:**
  - Executive summary of changes
  - Key facts and figures
  - Implementation timeline
  - Risk assessment
  - FAQ section
  - Success criteria
- **Best For:** Getting a quick understanding of the full scope

### 2. **REDIS_CACHE_QUICK_REF.md** (Quick Reference Checklist)

- **Purpose:** Quick lookup during development
- **Length:** ~200 lines
- **Contains:**
  - Redis keys requiring changes (organized by type)
  - New Redis keys to add (5 essential + optional)
  - Memory impact summary
  - Cache invalidation strategy
  - Implementation checklist (4 phases)
  - TTL recommendations
  - File list to update
- **Best For:** Quick reference during coding, checklists during implementation

### 3. **REDIS_CACHE_MIGRATION.md** (Complete Technical Analysis)

- **Purpose:** Comprehensive technical deep-dive
- **Length:** ~600 lines
- **Contains 8 Sections:**
  1.  Overview of changes
  2.  Redis keys requiring changes (detailed)
  3.  New Redis keys to add (detailed)
  4.  Cache invalidation strategy (comprehensive)
  5.  Memory estimation (with calculations)
  6.  Recommended new keys checklist
  7.  TTL recommendations
  8.  Implementation priority (3 phases)
  9.  Sample cache builder code
  10. Summary table
  11. Timeline & effort estimation
- **Best For:** Deep technical understanding, architecture decisions

### 4. **REDIS_CACHE_IMPLEMENTATION.md** (Step-by-Step Guide)

- **Purpose:** Production-ready implementation guide
- **Length:** ~700 lines
- **Contains:**
  - Phase 1-5 with step-by-step instructions
  - **Complete code examples** for each builder:
    - TagCacheBuilder (updated)
    - CategoryCacheBuilder (updated)
    - ChannelCacheBuilder (updated)
    - VideoCategoryIndexBuilder (new)
    - VideoCategoriesLookupBuilder (new)
    - CategoryVideoCountBuilder (new)
  - CacheSyncService integration
  - Invalidation logic implementation
  - Testing checklist
  - Deployment checklist
- **Best For:** Actual implementation, copy-paste ready code

### 5. **REDIS_CACHE_VISUAL_GUIDE.md** (Architecture Diagrams)

- **Purpose:** Visual representation of architecture changes
- **Length:** ~400 lines
- **Contains:**
  - ASCII diagrams of current vs new architecture
  - Key changes matrix
  - Cache key relationships (before/after)
  - Memory layout visualizations
  - Query pattern evolution (before/after)
  - Builder execution order diagram
  - Invalidation flow diagrams
  - TTL lifecycle visualization
  - Implementation timeline diagram
- **Best For:** Understanding relationships, presenting to team

---

## 🗂️ How to Use This Documentation

### For Project Leads

1. Start with **REDIS_CACHE_SUMMARY.md**
   - Understand scope, timeline, risks
   - Review success criteria
   - Make Go/No-Go decision

2. Refer to **REDIS_CACHE_QUICK_REF.md**
   - Overview of checklist
   - Resource estimation

### For Architects

1. Read **REDIS_CACHE_MIGRATION.md** (complete analysis)
2. Review **REDIS_CACHE_VISUAL_GUIDE.md** (architecture)
3. Reference **REDIS_CACHE_IMPLEMENTATION.md** (for detail)

### For Developers

1. Start with **REDIS_CACHE_VISUAL_GUIDE.md** (understand structure)
2. Follow **REDIS_CACHE_IMPLEMENTATION.md** (step-by-step)
3. Use **REDIS_CACHE_QUICK_REF.md** (daily reference)
4. Reference **REDIS_CACHE_MIGRATION.md** (when questions arise)

### For DevOps/SRE

1. Review **REDIS_CACHE_MIGRATION.md** (memory section)
2. Check **REDIS_CACHE_IMPLEMENTATION.md** (deployment section)
3. Monitor metrics listed in **REDIS_CACHE_SUMMARY.md**

---

## 📊 Quick Facts at a Glance

### Database Changes (Already Completed ✅)

```
Channel.prisma:   ADD categories, tags, tagNames (JSON)
Category.prisma:  REMOVE channelId; ADD tags (JSON), tagNames
VideoMedia.prisma: CHANGE categoryId → categoryIds
Tag.prisma:       REMOVE channelId
```

### Redis Keys Changes

| Type   | Action         | Keys Affected                                   | Count |
| ------ | -------------- | ----------------------------------------------- | ----- |
| Change | Update payload | app:video:detail, app:category:all, app:tag:all | 3     |
| Add    | New indexes    | 5 new patterns                                  | 5     |
| Change | Remove field   | Tag/Category builders                           | 2     |

### Memory Impact

- **Current:** 45 MB
- **After:** 80 MB
- **Increase:** +35 MB (acceptable)

### Timeline

- **Phase 1:** 2-3 days (DB migrations)
- **Phase 2:** 2-3 days (builder updates)
- **Phase 3:** 1-2 days (new builders)
- **Phase 4:** 1 day (integration)
- **Phase 5:** 2-3 days (testing & deploy)
- **Total:** 8-12 days

### Team & Risk

- **Team Size:** 1-2 backend engineers
- **Risk Level:** Medium
- **Critical Success Factor:** Thorough testing with 58K videos

---

## 🎯 Key Implementation Steps

### Phase 1: Database Schema ✅ (DONE)

- [x] Update Channel.prisma
- [x] Update Category.prisma
- [x] Update VideoMedia.prisma
- [x] Update Tag.prisma
- [ ] Create migration
- [ ] Run migration

### Phase 2: Cache Builders 🔄 (NEXT)

- [ ] Update TagCacheBuilder (code provided)
- [ ] Update CategoryCacheBuilder (code provided)
- [ ] Update ChannelCacheBuilder (code provided)
- [ ] Update VideoMedia builder
- [ ] Test with full dataset

### Phase 3: Index Builders 🆕 (NEW)

- [ ] Create VideoCategoryIndexBuilder (code provided)
- [ ] Create VideoCategoriesLookupBuilder (code provided)
- [ ] Create CategoryVideoCountBuilder (code provided)
- [ ] Integrate with CacheSyncService

### Phase 4: Production Ready 🚀

- [ ] Invalidation logic
- [ ] TTL management
- [ ] Monitoring & alerts
- [ ] Deployment plan

---

## 📋 New Redis Keys Summary

### Essential (Mandatory)

1. **app:video:category:index:{categoryId}:videos** (ZSET)
   - Multi-category video listing
   - Memory: +12.2 MB
   - TTL: 2 hours

2. **app:video:categories:{videoId}** (SET)
   - Video→categories lookup
   - Memory: +7.5 MB
   - TTL: 24 hours

3. **app:category:video:count:{categoryId}** (STRING)
   - Count for UI display
   - Memory: +80 KB
   - TTL: 1 hour

### Optional (Performance)

4. **app:tag:search:{prefix}** (SET)
   - Tag autocomplete
   - Memory: +0.5-1 MB
   - TTL: 2 hours

5. **app:category:tagnames:flat:{categoryId}** (STRING)
   - Flat tag names for search
   - Memory: +400 KB
   - TTL: 24 hours

---

## ✅ Validation Checklist

### Before Starting

- [ ] Read REDIS_CACHE_SUMMARY.md
- [ ] Review REDIS_CACHE_VISUAL_GUIDE.md
- [ ] Understand Phase 1-5 in REDIS_CACHE_IMPLEMENTATION.md
- [ ] Ensure Redis headroom: 100+ MB available

### During Implementation

- [ ] Follow REDIS_CACHE_IMPLEMENTATION.md step-by-step
- [ ] Reference REDIS_CACHE_QUICK_REF.md for checklists
- [ ] Use code from REDIS_CACHE_IMPLEMENTATION.md
- [ ] Test each phase before proceeding

### Before Production

- [ ] Load test with 58K+ videos
- [ ] Verify memory usage < 80 MB
- [ ] Check cache hit rates > 90%
- [ ] Validate response times < 100ms
- [ ] Test invalidation logic thoroughly

---

## 🔍 Documentation Cross-References

### Finding Information

**"How do I implement the builders?"**
→ REDIS_CACHE_IMPLEMENTATION.md, Phase 2-3

**"What memory will this use?"**
→ REDIS_CACHE_MIGRATION.md, Part 4

**"What are the new Redis keys?"**
→ REDIS_CACHE_QUICK_REF.md, "NEW Redis Keys to Add"

**"How does invalidation work?"**
→ REDIS_CACHE_MIGRATION.md, Part 3
→ REDIS_CACHE_IMPLEMENTATION.md, Phase 5

**"What's the timeline?"**
→ REDIS_CACHE_SUMMARY.md, Implementation Timeline

**"Show me the architecture"**
→ REDIS_CACHE_VISUAL_GUIDE.md, all sections

**"Where are the code examples?"**
→ REDIS_CACHE_IMPLEMENTATION.md, Phase 2-3

**"What should I test?"**
→ REDIS_CACHE_IMPLEMENTATION.md, Phase 6

**"How do I deploy?"**
→ REDIS_CACHE_IMPLEMENTATION.md, Deployment Checklist

---

## 📑 File Locations

All files are in the repository root:

```
box-nestjs-monorepo/
├── REDIS_CACHE_SUMMARY.md                 (Start here)
├── REDIS_CACHE_QUICK_REF.md               (Quick lookup)
├── REDIS_CACHE_MIGRATION.md               (Deep analysis)
├── REDIS_CACHE_IMPLEMENTATION.md          (Step-by-step)
├── REDIS_CACHE_VISUAL_GUIDE.md            (Diagrams)
└── REDIS_CACHE_INDEX.md                   (This file)
```

---

## 🚀 Quick Start (5 Minutes)

1. **Read:** REDIS_CACHE_SUMMARY.md (10 min)
2. **Skim:** REDIS_CACHE_VISUAL_GUIDE.md (5 min)
3. **Decision:** Go/No-Go based on timeline and resources
4. **Start:** Follow Phase 1 in REDIS_CACHE_IMPLEMENTATION.md

---

## 📞 Questions & Answers

### Q: Which document should I read first?

**A:** REDIS_CACHE_SUMMARY.md for overview, then REDIS_CACHE_VISUAL_GUIDE.md for understanding

### Q: Where are the code examples?

**A:** REDIS_CACHE_IMPLEMENTATION.md has complete production-ready code for all builders

### Q: Can I copy-paste the code?

**A:** Yes, all code in REDIS_CACHE_IMPLEMENTATION.md is copy-paste ready

### Q: How much time will this take?

**A:** 8-12 days for full implementation (see REDIS_CACHE_SUMMARY.md)

### Q: What's the risk level?

**A:** Medium (well-mitigated with comprehensive guides provided)

### Q: Do I need to update application code?

**A:** Yes, code using `categoryId` must change to `categoryIds` (array)

### Q: Can I rollback if issues occur?

**A:** Yes, rollback plan is documented in REDIS_CACHE_SUMMARY.md

---

## 🎓 Learning Path

```
Beginner:
  1. REDIS_CACHE_SUMMARY.md (overview)
  2. REDIS_CACHE_VISUAL_GUIDE.md (architecture)
  3. REDIS_CACHE_QUICK_REF.md (quick facts)

Intermediate:
  4. REDIS_CACHE_MIGRATION.md (technical detail)
  5. REDIS_CACHE_QUICK_REF.md (checklists)

Advanced:
  6. REDIS_CACHE_IMPLEMENTATION.md (code)
  7. Deep code review and testing
```

---

## ✨ Key Highlights

### What's Great About This Migration

✅ Multi-category support enables flexible content organization  
✅ Denormalization improves query performance  
✅ New indexes support efficient multi-category queries  
✅ Backward compatible migration path  
✅ Comprehensive documentation provided

### What Requires Attention

⚠️ Memory increases by 66% (plan accordingly)  
⚠️ All cache builders need updates  
⚠️ Thorough testing critical with 58K videos  
⚠️ Application code needs updates  
⚠️ Invalidation logic must be precise

---

## 📞 Support Resources

### In This Documentation

- ✅ Complete analysis and reasoning
- ✅ Step-by-step implementation guide
- ✅ Production-ready code examples
- ✅ Testing and deployment checklists
- ✅ Architecture diagrams
- ✅ Quick reference guides

### External Resources

- Redis Documentation: https://redis.io/docs/
- NestJS Caching: https://docs.nestjs.com/techniques/caching
- Prisma Relations: https://www.prisma.io/docs/concepts/relations

---

## 🎯 Success Metrics

Track these after deployment:

1. **Cache Hit Rate** (target: >90%)
2. **Memory Usage** (target: <80 MB)
3. **Query Response Time** (target: <100ms)
4. **Index Freshness** (target: <2 hours old)
5. **Zero Errors** in application logs

---

## 📝 Notes

- Prisma schema files already updated ✅
- This documentation is comprehensive and ready to use
- No external dependencies beyond what's already in the project
- Timeline is realistic with proper team coordination
- Risk is manageable with thorough testing

---

**START HERE:** Read `REDIS_CACHE_SUMMARY.md` first

**THEN:** Review `REDIS_CACHE_VISUAL_GUIDE.md` for architecture understanding

**FINALLY:** Follow `REDIS_CACHE_IMPLEMENTATION.md` for step-by-step implementation

---

**Total Documentation:** ~2000+ lines  
**Code Examples Provided:** 6 complete builders  
**Ready to Implement:** Yes ✅