Continuous Data Pipelines

Build end-to-end change data capture (CDC) flows in Databend with two primitives:

• Streams capture every INSERT/UPDATE/DELETE until you consume them.
• Tasks run SQL on a schedule or when a stream reports new rows.

Quick Navigation

• Example 1: Append-Only Stream Copy – capture inserts and consume them into another table.
• Example 2: Standard Stream Updates – see how updates/deletes appear and why only one consumer can drain a stream.
• Example 3: Incremental Stream Metrics – join multiple streams with WITH CONSUME to compute deltas batch by batch.
• Example 1: Scheduled Copy Task – generate and load files with two recurring tasks.
• Example 2: Stream-Triggered Merge – fire a task only when STREAM_STATUS is true.

Why CDC in Databend

• Lightweight – streams keep the latest change set without duplicating full tables.
• Transactional – stream consumption succeeds or rolls back with your SQL statement.
• Incremental – rerun the same query with WITH CONSUME to process only new rows.
• Schedulable – tasks let you automate the copy, merge, or alert logic you already expressed in SQL.

Dive into the stream examples first, then combine them with tasks to automate your pipeline.