[CASSANDRA-17666] Option to disable write path during streaming for CDC enabled tables

• Type: Improvement
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 5.0-alpha1, 5.0
• Component/s: Feature/Change Data Capture
• Change Category: Operability
• Complexity: Normal
• Platform: All

Source Control Link

https://github.com/apache/cassandra/commit/99d034a2245c44becb6a730c77ad51ab9340f3a7

Test and Documentation Plan

in-jvm dtest; ci

• Assignee: Yifan Cai
• Reporter: Yifan Cai

Authors

Yifan Cai

Reviewers

Josh McKenzie

• Created: 26/May/22 20:47
• Updated: 13/Sep/24 19:18
• Resolved: 07/Jun/22 18:32

Description

For the CDC-enabled tables, a special write path is employed during streaming. The mutations streamed are written into commit log first.

There are scenarios that the commit logs can accumulate, which lead to failure of streaming and blocking writes.

I'd like to propose adding a dynamic toggle to disable the special write path for CDC during streaming.

Please note that the toggle is a trade-off. Because the special write path is there in the hope to ensure data consistency. Turning it off allows the streaming to pass, but in some extreme scenarios, the downstream CDC consumers may have holes in the stream, depending on how they consumes the commit logs.

Issue Links

• causes: CASSANDRA-17792 Fix race condition on updating cdc size and advancing to next segment