Senior LevelSoftware Engineering Principles
How does Change Data Capture (CDC) with Debezium capture database write-ahead logs for event streaming?
❓ Interview Prompt: Explain Change Data Capture (CDC), Debezium, reading database Write-Ahead Logs (WAL/binlog), zero-impact event streaming, and outbox patterns.
Change Data Capture (CDC) streams low-level database row insertions, updates, and deletions into event brokers (Kafka) by reading the database's native transaction log (Write-Ahead Log / Binlog):
Advantages over Application Polling:
1
Zero Application Changes: Captures DB changes without requiring application code modifications or triggers.
2
No Performance Impact: Reads binary log files directly from disk without executing heavy SQL queries.
3
Guaranteed Captures: Never misses hard deletes or bulk database updates.
Code Implementation Example
json
// Debezium CDC Event Payload captured from PostgreSQL WAL
{
"op": "u", // Update operation
"before": { "id": 10, "status": "PENDING" },
"after": { "id": 10, "status": "SHIPPED" },
"source": { "db": "orders", "table": "order_records", "lsn": 24891024 }
}💡Debezium Change Data Capture (CDC) JSON event payload.
🎯 Interview Key Takeaway
Deploy Change Data Capture (CDC) with Debezium to stream database transaction log changes into Kafka with zero performance overhead.
#CDC#Debezium#Event Streaming#Senior
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