Debezium Server fails to start

[mfvitale]

Bug report

What Debezium connector do you use and what version?

Debezium Server 3.6.0-SNAPSHOT

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What is the connector configuration?

debezium.sink.type=http
debezium.sink.http.url=http://locahost:80
debezium.format.value=json
debezium.source.connector.class=io.debezium.connector.mysql.MySqlConnector
debezium.source.offset.storage.file.filename=/tmp/offsets.dat
debezium.source.offset.flush.interval.ms=60000
debezium.source.topic.prefix=test
debezium.source.database.hostname=localhost
debezium.source.database.port=4301
debezium.source.database.user=mysqluser
debezium.source.database.password=mysqlpw
debezium.source.database.server.id=184054
debezium.source.schema.history.internal=io.debezium.relational.history.MemorySchemaHistory
debezium.source.database.jdbc.driver.allowPublicKeyRetrieval=true
quarkus.log.console.json=false

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What is the captured database version and mode of deployment?

MySQL

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What behavior do you expect?

Debezium Server should start

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What behavior do you see?

After https://github.com/debezium//dbz/issues/1755 Debezium Server fails with:

2026-04-08 08:04:50,718 INFO  [io.deb.uti.Threads] (debezium-mysqlconnector-test-change-event-source-coordinator) Requested thread factory for component MySqlConnect
2026-04-08 08:04:50,721 INFO  [io.deb.con.bin.BinlogStreamingChangeEventSource] (debezium-mysqlconnector-test-change-event-source-coordinator) Enable ssl PREFERRED m
2026-04-08 08:04:50,733 ERROR [io.deb.pip.ErrorHandler] (debezium-mysqlconnector-test-change-event-source-coordinator) Producer failure: java.lang.IllegalStateExcept
        at java.base/java.util.stream.Collectors.duplicateKeyException(Collectors.java:135)
        at java.base/java.util.stream.Collectors.lambda$uniqKeysMapAccumulator$1(Collectors.java:182)
        at java.base/java.util.stream.ReduceOps$3ReducingSink.accept(ReduceOps.java:169)
        at java.base/java.util.HashMap$EntrySpliterator.forEachRemaining(HashMap.java:1858)
        at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:762)
        at java.base/java.util.stream.ReferencePipeline$7$1.accept(ReferencePipeline.java:276)
        at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197)
        at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1708)
        at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509)
        at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
        at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:921)
        at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
        at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:682)
        at io.debezium.pipeline.ChangeEventSourceCoordinator.registerSignalActionsAndStartProcessor(ChangeEventSourceCoordinator.java:179)
        at io.debezium.pipeline.ChangeEventSourceCoordinator.lambda$streamEvents$5(ChangeEventSourceCoordinator.java:330)
        at java.base/java.util.Optional.ifPresent(Optional.java:178)
        at io.debezium.pipeline.ChangeEventSourceCoordinator.streamEvents(ChangeEventSourceCoordinator.java:330)
        at io.debezium.pipeline.ChangeEventSourceCoordinator.executeChangeEventSources(ChangeEventSourceCoordinator.java:217)
        at io.debezium.pipeline.ChangeEventSourceCoordinator.lambda$start$0(ChangeEventSourceCoordinator.java:148)
        at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:572)
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
        at io.debezium.util.Threads$3.lambda$newThread$0(Threads.java:314)
        at java.base/java.lang.Thread.run(Thread.java:1583)

2026-04-08 08:04:55,947 INFO  [io.deb.ser.htt.HttpChangeConsumer] (pool-8-thread-1) Failed to send event: null
2026-04-08 08:04:57,167 INFO  [io.deb.ser.htt.HttpChangeConsumer] (pool-8-thread-1) Failed to send event: null
2026-04-08 08:04:58,380 INFO  [io.deb.ser.htt.HttpChangeConsumer] (pool-8-thread-1) Failed to send event: null
2026-04-08 08:04:59,591 INFO  [io.deb.ser.htt.HttpChangeConsumer] (pool-8-thread-1) Failed to send event: null
2026-04-08 08:05:00,819 INFO  [io.deb.ser.htt.HttpChangeConsumer] (pool-8-thread-1) Failed to send event: null
2026-04-08 08:05:00,822 ERROR [io.deb.emb.asy.AsyncEmbeddedEngine] (pool-7-thread-1) Engine has failed with : java.util.concurrent.ExecutionException: io.debezium.DebeziumException: Error while executing batch
        at java.base/java.util.concurrent.FutureTask.report(FutureTask.java:122)
        at java.base/java.util.concurrent.FutureTask.get(FutureTask.java:191)
        at io.debezium.embedded.async.AsyncEmbeddedEngine.runTasksPolling(AsyncEmbeddedEngine.java:536)
        at io.debezium.embedded.async.AsyncEmbeddedEngine.run(AsyncEmbeddedEngine.java:222)
        at io.debezium.server.DebeziumServer.lambda$start$0(DebeziumServer.java:166)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
        at java.base/java.lang.Thread.run(Thread.java:1583)
Caused by: io.debezium.DebeziumException: Error while executing batch
        at io.debezium.server.DefaultChangeConsumer.handleBatch(DefaultChangeConsumer.java:61)
        at io.debezium.embedded.async.ParallelSmtAndConvertBatchProcessor.processRecords(ParallelSmtAndConvertBatchProcessor.java:56)
        at io.debezium.embedded.async.AsyncEmbeddedEngine$PollRecords.doCall(AsyncEmbeddedEngine.java:1251)
        at io.debezium.embedded.async.AsyncEmbeddedEngine$PollRecords.doCall(AsyncEmbeddedEngine.java:1229)
        at io.debezium.embedded.async.RetryingCallable.call(RetryingCallable.java:47)
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)
        at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:572)
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)

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Do you see the same behaviour using the latest released Debezium version?

Yes

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Do you have the connector logs, ideally from start till finish?

Already provided above

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How to reproduce the issue using our tutorial deployment?

Just running a Debezium Server instance