Intermediate LevelSystem Design & Architecture
What is Change Data Capture (CDC) and how does Debezium stream database mutations?
❓ Interview Prompt: Explain Change Data Capture (CDC), Debezium connector, tailing database transaction logs (binlog/WAL), and zero-query-overhead event streaming.
Change Data Capture (CDC) streams database row mutations ('INSERT', 'UPDATE', 'DELETE') into event brokers (Kafka) by tailing the database's native transaction log (MySQL binlog / Postgres WAL):
Advantages over DB Polling:
•
Zero Application Changes: Captures DB mutations without application code changes.
•
Zero Query Overhead: Tails log files on disk without executing heavy 'SELECT' queries on primary database tables.
•
Captures Deletes: Reliable event detection for hard deletes.
Code Implementation Example
json
{
"before": { "id": 10, "status": "PENDING" },
"after": { "id": 10, "status": "SHIPPED" },
"op": "u",
"source": { "db": "orders", "table": "order_records" }
}💡Debezium Change Data Capture (CDC) JSON event payload.
🎯 Interview Key Takeaway
Deploy Change Data Capture (CDC) with Debezium to stream database mutations into Kafka with zero performance impact on database query engines.
#System Design#CDC#Debezium#Kafka#Intermediate
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