CHANGE DATA CAPTURE
Real-time replication, straight from the transaction log.
Weld CDC captures every insert, update and delete from PostgreSQL, MySQL, SQL Server and MongoDB — and applies them to your warehouse in seconds, not hours.
Loved by data teams from around the world
COMPARISON
CDC vs other sync modes
Weld supports incremental, full and CDC replication. Choose the right mode for each source based on your latency and completeness requirements.
Learn more in docs| Approach | How it works | Deletes | Low latency | Low load |
|---|---|---|---|---|
| Full table sync | Re-copy entire tables on schedule | ✗ | ✗ | ✗ |
| Incremental sync | Pull rows using timestamps or IDs | ⚠ | ⚠ | ✓ |
| Change Data Capture | Stream changes from transaction logs | ✓ | ✓ | ✓ |
WHY CDC
Built for production workloads
Log-based CDC designed for reliability, low overhead, and operational simplicity — from initial setup to ongoing monitoring.
Near real-time replication
Capture inserts, updates and deletes within seconds. No more waiting for hourly or daily batch jobs.
Low source impact
Log-based CDC reads from the transaction log — no table scans, no query load on your production database.
Reliable deletes & updates
Unlike incremental syncs, CDC captures every change type including hard deletes and in-place updates.
Automatic schema handling
Column additions are propagated automatically. Schema changes are detected and handled without manual intervention.
Ordering guarantees
Changes are delivered in transaction-log order. Your destination reflects the source state accurately.
Self-healing pipelines
If a connection drops, CDC resumes from the last checkpoint. No data is lost, no manual restarts needed.
HOW IT WORKS
From transaction log to warehouse in four steps
No table scans, no polling. Weld reads directly from the database's native change stream and merges changes into your warehouse automatically.
Read the full guideRead transaction log
Weld reads from the database's native transaction log (WAL, binlog, oplog) without touching your tables.
SUPPORTED DATABASES
Log-based CDC for the databases you use
Each database has a dedicated setup guide with step-by-step instructions for enabling CDC.
RESOURCES
Learn more about CDC
Guides, docs and resources to help you get the most out of Change Data Capture with Weld.
BEST FOR
When to use CDC
- Near real-time replication (seconds, not hours)
- Reliable deletes & updates, not just new rows
- Reducing load on large production tables
- Event-driven downstream systems
ALTERNATIVE
When batch is enough
- Small, slowly changing datasets
- Hourly or daily freshness is acceptable
- Simplest possible setup preferred
- Source doesn't expose a transaction log
AWARD WINNING ETL PLATFORM
Recognized as a leading ETL platform for seamless data movement
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