KAFKA-19955: Fix performance regression in server-side assignors#21058
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dajac merged 2 commits intoapache:trunkfrom Dec 3, 2025
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KAFKA-19955: Fix performance regression in server-side assignors#21058dajac merged 2 commits intoapache:trunkfrom
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| /** | ||
| * The partition assignment for a modern group member. | ||
| * | ||
| * @param partitions The partitions assigned to this member keyed by topicId. |
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Thanks for the review. I tried to expand the javadoc.
The server-side assignors are designed to re-use the previous assignment maps where possible and clone them for modification lazily. apache#20097 introduced a bug where the assignments would always be re-wrapped in an unmodifiable map and so we would end up cloning them repeatedly in the assignors when multiple changes need to be made to a member assignment. Fix the bug by removing the unmodifiable map wrapping.
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@squah-confluent I wonder whether we could add tests for all the assignors to ensure that they actually preserve input maps if there are no changes. It would be better to avoid any future regression. What do you think? |
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) The server-side assignors are designed to re-use the previous assignment maps where possible and clone them for modification lazily. #20097 introduced a bug where the assignments would always be re-wrapped in an unmodifiable map and so we would end up cloning them repeatedly in the assignors when multiple changes need to be made to a member assignment. Fix the bug by removing the unmodifiable map wrapping. Reviewers: David Jacot <[email protected]>
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Merged to trunk and 4.2. |
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Looks like the mechanism we use to decide if a map should be cloned is brittle. Perhaps, it should be a more explicit mechanism so these kinds of bugs are not possible. |
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…che#21058) The server-side assignors are designed to re-use the previous assignment maps where possible and clone them for modification lazily. apache#20097 introduced a bug where the assignments would always be re-wrapped in an unmodifiable map and so we would end up cloning them repeatedly in the assignors when multiple changes need to be made to a member assignment. Fix the bug by removing the unmodifiable map wrapping. Reviewers: David Jacot <[email protected]>
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The server-side assignors are designed to re-use the previous assignment
maps where possible and clone them for modification lazily. #20097
introduced a bug where the assignments would always be re-wrapped in an
unmodifiable map and so we would end up cloning them repeatedly in the
assignors when multiple changes need to be made to a member assignment.
Fix the bug by removing the unmodifiable map wrapping.
Reviewers: David Jacot [email protected]