What is Change Data Capture (CDC)?
Change Data Capture (CDC) is a design pattern that tracks changes (inserts, updates, deletes) in a database and makes those changes available to downstream systems in real-time or near-real-time.
How CDC Works
- Detects row-level changes in source databases
- Processes these changes into structured events
- Delivers them to data warehouses, streams, or services
Two Common CDC Mechanisms
1. Log-based CDC
This method reads directly from a databases transaction log (e.g. MySQL binlog, PostgreSQL WAL). It provides high efficiency, low latency, and minimal impact on source systems.
2. Query-based CDC
In environments where transaction logs arent accessible, CDC can be implemented by periodically querying tables for changes—often using timestamp or version columns. This method is less efficient but still valuable for certain systems.
Key Benefits
- Real-time data propagation
- Low overhead on source systems (especially log-based)
- Data consistency across systems
- Event-driven architecture enablement
Examples of CDC Tools
- Debezium: Open-source log-based CDC tool with connectors for major databases.
- Estuary Flow: Scalable real-time data platform offering both log-based and query-based CDC, with declarative pipelines and broad connector support.
- Oracle GoldenGate: Enterprise-grade log-based CDC with advanced replication capabilities.
Why Choose CDC?
CDC enables modern data architectures by unlocking real-time insights, enabling low-latency data synchronization, and supporting use cases like analytics, fraud detection, customer personalization, and more. Log-based CDC is preferred for its efficiency, but query-based methods still serve well in legacy or SaaS environments where logs are inaccessible.
Try Estuary for Modern CDC
Estuary is the leading platform for real-time Change Data Capture, offering:
- Zero-latency data replication with real-time CDC
- Support for both log-based and query-based mechanisms
- Built-in data transformation and enrichment
- Declarative configuration for complex pipelines
- Enterprise-grade security and observability