[jira] [Created] (KAFKA-13261) KTable to KTable foreign key join does not produce output when using several partitions

["Tomas Forsman (Jira)" <ji...@apache.org>]

Tomas Forsman created KAFKA-13261:
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             Summary: KTable to KTable foreign key join does not produce output when using several partitions
                 Key: KAFKA-13261
                 URL: https://issues.apache.org/jira/browse/KAFKA-13261
             Project: Kafka
          Issue Type: Bug
          Components: streams
    Affects Versions: 2.7.1, 2.8.0
            Reporter: Tomas Forsman


Two incoming streams A and B. 

Stream A uses a composite key [a, b]

Stream B has key [b]

Stream B has 4 partitions and steams A has 1 partition.

What we try to do is repartition stream B to 4 partitions, then put both A and B into KTable and do a foreign key join on B

When doing this, all messages does not end up in the output topic.

Repartitioning both to only use 1 partition each solve the problem so it seem like it has something to do with the foreign key join in combination with several partitions. 

One suspicion would be the internal topics created for the join and that it is not possible to define what partitioner to use for the join.

Any insight or help is greatly appreciated.

*Example code of the problem*
{code:java}

static Topology createTopoology(){
    var builder = new StreamsBuilder();

    KTable<String, String> tableB = builder.table("B",  stringMaterialized("customeraccess.table"));

    builder
        .stream("A", Consumed.with(Serde.of(KeyA.class), Serde.of(EventA.class)))
        .repartition(repartitionTopicA())
        .toTable(Named.as("table.a"), driverPeriodMaterialized("table.a"))
        .join(tableB, EventA::getKeyB, topicAandBeJoiner(), Named.as("join.ab"), joinMaterialized("join.ab"))
        .toStream()
        .to("output", with(...));

    return builder.build();
}

private static Repartitioned<DriverPeriod, DriverCosts> repartitionTopicA() {
    Repartitioned<DriverPeriod, DriverCosts> repartitioned = Repartitioned.as("driverperiod");
    return repartitioned.withKeySerde(Serde.of(KeyA.class)).withValueSerde(Serde.of(EventA.class))
        .withStreamPartitioner(topicAPartitioner())
        .withNumberOfPartitions(4);
}

private static StreamPartitioner<DriverPeriod, DriverCosts> topicAPartitioner() {
    return (topic, key, value, numPartitions) -> Math.abs(key.getKeyB().hashCode()) % numPartitions;
}

private static Materialized<KeyA, EventA, KeyValueStore<Bytes, byte[]>> joinMaterialized(String name) {
    Materialized<DriverPeriod, DriverCosts, KeyValueStore<Bytes, byte[]>> table = Materialized.as(name);
    return table.withKeySerde(Serde.of(KeyA.class)).withValueSerde(Serde.of(EventA.class));
}

{code}



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