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Matthias J. Sax commented on KAFKA-14747: ----------------------------------------- It seems [~kooooma] did never find time to pick it up – let's give him a few days to response – if he does not response, feel free to pick it up. About testing: not sure from top of my head; could also just be a test gap. – IIRC (did not check the code), we don't use the dropped record sensor for this case, and thus it might not have been important to test; if we add tracking dropped records with this ticket, it seems reasonable to also start testing the sensor (if possible). > FK join should record discarded subscription responses > ------------------------------------------------------ > > Key: KAFKA-14747 > URL: https://issues.apache.org/jira/browse/KAFKA-14747 > Project: Kafka > Issue Type: Improvement > Components: streams > Reporter: Matthias J. Sax > Assignee: Koma Zhang > Priority: Minor > Labels: beginner, newbie > > FK-joins are subject to a race condition: If the left-hand side record is > updated, a subscription is sent to the right-hand side (including a hash > value of the left-hand side record), and the right-hand side might send back > join responses (also including the original hash). The left-hand side only > processed the responses if the returned hash matches to current hash of the > left-hand side record, because a different hash implies that the lef- hand > side record was updated in the mean time (including sending a new > subscription to the right hand side), and thus the data is stale and the > response should not be processed (joining the response to the new record > could lead to incorrect results). > A similar thing can happen on a right-hand side update that triggers a > response, that might be dropped if the left-hand side record was updated in > parallel. > While the behavior is correct, we don't record if this happens. We should > consider to record this using the existing "dropped record" sensor or maybe > add a new sensor. -- This message was sent by Atlassian Jira (v8.20.10#820010)