In data engineering, one of the most important questions we face is: đ How do we load only the new or changed data efficiently? Two widely used strategies are: Watermarking and Change Data Capture (CDC). Both avoid costly full reloads, but their use-cases differ. Hereâs a breakdown âŹď¸ đ Watermarking (Incremental Loads) â Tracks the last processed point (often a timestamp, identity column, or version number). â Easy to configure in ADF copy activity or Databricks notebooks. â Best for append-only data: IoT events, transaction logs, telemetry, clickstreams. â ď¸ Limitation: If source data is updated or deleted, watermarking wonât capture it. đ Change Data Capture (CDC) â Captures inserts, updates, and deletes directly from the source (via SQL Server CDC, Debezium, ADF Change Tracking, etc.). â Ensures true data fidelity in Delta Lake â including Slowly Changing Dimensions (SCDs) and full auditing. â Works best for OLTP systems, ERP/CRM migrations, and scenarios where business rules depend on changes. â ď¸ Slightly more complex setup and often requires extra infra (logs, Kafka, CDC tables). đ In Real Projects Start with Watermarking â when the source is append-only and simplicity is key (ex: sales transactions, telemetry feeds). Move to CDC â when you need complete historical accuracy (SCD Type 2, audit logs, backtracking business events). Use Both Together â Watermarking as a baseline for detecting new records. CDC for handling updates/deletes on top of the incremental load. Example: A retail system where new sales come via Watermarking but price updates/cancellations are handled via CDC. đš Key takeaway: Itâs not always Watermarking vs CDC. In modern data platforms, you often need both strategiesworking together for a truly resilient data pipeline. #DataEngineering #AzureDataFactory #Databricks #DeltaLake #CDC #Watermarking #ETL #BigData #Azure #DataPipelines #Toronto #Database #sql #data #engineering #python #spark
Thanks for sharing
Insightful
Really like how you framed this đ In my experience, teams often default to full reloads simply because they underestimate how fragile pipelines become when governance isnât set from the start. Iâve seen cases where 60â70% of downstream dashboards broke â not because of tooling, but because changes werenât captured correctly upstream. Curious â when youâve introduced CDC in projects, whatâs been the biggest blocker: infra complexity, cost, or team skills?
Good explanation. Its all about how the data behaves, some time you need to updste old records , sometimes just get the new
Agreed. We need to choose them wisely
Great insight
The loading pattern speaks here from Delta to CDC, thanks for sharing
Great breakdown! Thanks for sharing!
I want to share my personal experience: when we made our infra we haven't taken care about to capture changes and track them, things were going smooth at least for 6 month, then we have to migration now the story getting interesting turn apparently all the stakeholders apparently asking for points and asking about the history the little changes in the data that we haven't done in our infra to capture, then we realized we have to process thing so we are using now "water marking" and "CDC" Thanks to Prasad Chokkakula this knowledge is very important not only the Pipelines are enough.
Senior Data Engineer at Fractal | Python | SQL | PySpark | Azure Data Factory | Azure Databricks | ADLS
3wGreat insights, Prasad! Your breakdown of Watermarking and Change Data Capture highlights the nuances in data engineering perfectly. It's clear that choosing the right strategy can significantly enhance data pipeline efficiency. Thank you for sharing your expertise!