What is Change Data Capture (CDC) in 90 Seconds

⚡ CDC in 90 seconds—let’s go!

🎵 TikTok

What is CDC?

Change Data Capture = Reading database changes in real-time

Instead of querying “SELECT * FROM users WHERE updated_at > last_sync”, CDC reads the database transaction log directly.

How It Works

Database Write → Transaction Log → CDC Tool → Stream (Kafka)

Example with Debezium:

1. User updates profile in Postgres
2. Postgres writes to WAL (Write-Ahead Log)
3. Debezium reads WAL
4. Change event sent to Kafka
5. Downstream systems react in real-time

Why CDC > Batch Sync

❌ Batch: Query every 15 minutes, miss changes in between
✅ CDC: Capture every change, <1 second latency

❌ Batch: Expensive full table scans
✅ CDC: Read only what changed

❌ Batch: Can’t capture deletes easily
✅ CDC: Sees inserts, updates, AND deletes

Real-World Use Case

E-commerce inventory sync:

• User buys product → Postgres updated
• CDC captures change → Sends to Kafka
• Cache invalidated → Search index updated → Analytics warehouse synced
• All in <500ms

Popular CDC Tools

• Debezium (open-source)
• AWS DMS (managed)
• Fivetran (SaaS)
• Airbyte (open-source)

That’s CDC. Real-time data movement without polling. 🚀

#DataEngineering #CDC #RealTimeData #Debezium