KAFKA-10844: KStream mark as partitioned#22221
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muralibasani
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May 9, 2026
| * | ||
| * @return a new, mutated {@code KStream} that will not repartition in subsequent operations. | ||
| */ | ||
| KStream<K, V> markAsPartitioned(); |
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Not sure if KStream.scala should also be updated with this ?
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Saw that KStream.scala is deprecated by 4.3... so maybe not worth updating?
muralibasani
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May 9, 2026
muralibasani
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May 9, 2026
| final String topologyNotMarked = builder.build().describe().toString(); | ||
| notMarked.markAsPartitioned(); | ||
| final String topologyMarked = builder.build().describe().toString(); | ||
| assertEquals(topologyNotMarked, topologyMarked); |
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May be also assert for notMarked and notMarked.markAsPartitioned() to be same as this is returned in the impl
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Hm... leaning towards keeping as is for the spec: "markAsPartitioned is no-op when no key changing". Testing implementation details might be an overkill.
muralibasani
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@zheguang I have a few minor comments.
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LGTM |
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This patch implements KIP-759: Unneeded repartition cancelling. The "unneeded" part is entirely by the user's own judgement :)
A stream with key-changing operation can be marked as partitioned as intended to avoid repartition inserted to its topology. The main use case is for aggregation by a "composite key" -- a stream partitioned by key A can readily aggregate by composite key (A, B) without repartition. The reason being given two records, if their (A, B) are equal, then their A is equal.
Spec/Test:
markAsPartitionedis no-op when no key changingmarkAsPartitionedshould not repartition in resulting topologymarkAsPartitionedmarkAsPartitioned