What is Change Data Capture?

Change Data Capture (CDC) is a process that captures changes made at the data source and applies them throughout the entire system. It minimizes resources required for ETL processes by dealing only with data changes, providing efficient, distributed, row-level change feeds into a configurable sink for downstream processing such as reporting, caching, or full-text indexing. CockroachDB's mission is to Make Data Easy and plays well with others using CDC. A CockroachDB `CHANGEFEED` is a realtime stream of changes happening in a table or tables, emitting messages to an external system called a "sink". The biggest challenge in building CDC changefeeds for CockroachDB was maintaining strong transaction semantics while scaling out horizontally. CockroachDB's unique distributed architecture led to the development of internal mechanisms like RangeFeed and resolved timestamp messages, ensuring data durability and consistency.