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Change data capture (CDC) detects row-level data changes in CockroachDB and emits those changes as messages for downstream processing. While CockroachDB is an excellent system of record, CDC allows it to integrate with other systems in your data ecosystem. For example, you might want to:
  • Stream messages to Kafka to trigger notifications in an application.
  • Mirror your data in full-text indexes, analytics engines, or big data pipelines.
  • Export a snapshot of tables to backfill new applications.
  • Feed updates to data stores powering machine learning models.

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Stream row-level changes with changefeeds

Changefeeds are customizable jobs that monitor row-level changes in a table and emit updates in real time. These updates are delivered in your preferred format to a specified destination, known as a sink. In production, changefeeds are typically configured with an external sink such as Kafka or cloud storage. However, for development and testing purposes, sinkless changefeeds allow you to stream change data directly to your SQL client. Each emitted row change is delivered at least once, and the first emit of every event for the same key is ordered by timestamp.

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Get started with changefeeds

To get started with changefeeds in CockroachDB, refer to:
  • Create and Configure Changefeeds: Learn about the fundamentals of using SQL statements to create and manage changefeeds.
  • Changefeed Sinks: The downstream system to which the changefeed emits changes. Learn about the supported sinks and configuration capabilities.
  • Changefeed Messages: The change events that emit from the changefeed. Learn about how messages are ordered and the options to configure and format messages.
  • Changefeed Examples: Step-by-step examples for connecting to changefeed sinks or running sinkless changefeeds.

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Authenticate to your changefeed sink

To send changefeed messages to a sink, it is necessary to provide the CREATE CHANGEFEED statement with authentication credentials. The following pages detail the supported authentication:

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Monitor your changefeed job

It is a best practice to monitor your changefeed jobs for behavior such as failures and retries. You can use the following tools for monitoring: Refer to the Monitor and Debug Changefeeds page for recommendations on metrics to track. For detail on how protected timestamps and garbage collection interact with changefeeds, refer to Protect Changefeed Data from Garbage Collection.

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Optimize a changefeed for your workload

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Filter your change data with CDC queries

Change data capture queries allow you to define and filter the change data emitted to your sink when you create an changefeed. For example, you can use CDC queries to: Refer to the Change Data Capture Queries page for more example use cases.

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Use changefeeds to export a table

Changefeeds can export a single table scan to your sink. The benefits of using changefeeds for exports include: job management, observability, and sink configurability. You can also schedule changefeeds to export tables, which may be useful to avoid table scans during peak periods. For examples and more detail, refer to:

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Determine the nodes running a changefeed by locality

CockroachDB supports an option to set locality filter requirements that nodes must meet in order to take part in a changefeed job. This is helpful in multi-region clusters to ensure the nodes that are physically closest to the sink emit changefeed messages. For syntax and further technical detail, refer to Run a changefeed job by locality.