[BP-0.8][docs] Clarify the supported flink versions for delta join #2030
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(cherry picked from commit 4f00709)
| - The downstream node of the join must support idempotent updates, typically it's an upsert sink and should not have a `SinkUpsertMaterializer` node before it. | ||
| - Flink planner automatically inserts a `SinkUpsertMaterializer` when the sink’s primary key does not fully cover the upstream update key. | ||
| - You can learn more details about `SinkUpsertMaterializer` by reading this [blog](https://www.ververica.com/blog/flink-sql-secrets-mastering-the-art-of-changelog-events). | ||
| - Since delta join does not support to handle update-before messages, it is necessary to ensure that the entire pipeline can safely discard update-before messages. That means when consuming a CDC stream: |
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Since delta join does not support to handle update-before messages
Seems like a typo here, do you mean?
Since delta join does not support update-before messages
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In Flink, when consuming a changelog source, the source operator may output insert, update-before, update-after, and delete messages (update-before and update-after originate from an update statement in the storage engine.).
Here, I would like to express that the delta join operator cannot handle (consume) the update-before messages output by the source operator.
wuchong
approved these changes
Dec 2, 2025
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Purpose
Linked issue: close #1986
Brief change log
BP #2000 to release-0.8
Tests
API and Format
Documentation