NPE throw when get bucket count from MetadataUpdater

[swuferhong]

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Fluss version

0.8.0 (latest release)

Please describe the bug 🐞

The error is as follow:

2025-11-30 13:21:54
java.io.IOException: Failed to send record to table fluss.dwd_xxx. Writer state: running
	at org.apache.fluss.flink.sink.writer.FlinkSinkWriter.write(FlinkSinkWriter.java:159)
	at org.apache.flink.streaming.runtime.operators.sink.SinkWriterOperator.processElement(SinkWriterOperator.java:182)
	at org.apache.flink.streaming.runtime.tasks.OneInputStreamTask$StreamTaskNetworkOutput.emitRecord(OneInputStreamTask.java:245)
	at org.apache.flink.streaming.runtime.io.AbstractStreamTaskNetworkInput.processElement(AbstractStreamTaskNetworkInput.java:217)
	at org.apache.flink.streaming.runtime.io.AbstractStreamTaskNetworkInput.emitNext(AbstractStreamTaskNetworkInput.java:169)
	at org.apache.flink.streaming.runtime.io.StreamOneInputProcessor.processInput(StreamOneInputProcessor.java:68)
	at org.apache.flink.streaming.runtime.tasks.StreamTask.processInput(StreamTask.java:616)
	at org.apache.flink.streaming.runtime.tasks.mailbox.MailboxProcessor.runMailboxLoop(MailboxProcessor.java:231)
	at org.apache.flink.streaming.runtime.tasks.StreamTask.runMailboxLoop(StreamTask.java:1071)
	at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:1020)
	at org.apache.flink.runtime.taskmanager.Task.runWithSystemExitMonitoring(Task.java:968)
	at org.apache.flink.runtime.taskmanager.Task.restoreAndInvoke(Task.java:947)
	at org.apache.flink.runtime.taskmanager.Task.doRun(Task.java:754)
	at org.apache.flink.runtime.taskmanager.Task.run(Task.java:569)
	at java.lang.Thread.run(Thread.java:879)
Caused by: org.apache.fluss.exception.FlussRuntimeException: Failed to send record to table fluss.dwd_xxx. Writer state: running
	at org.apache.fluss.client.write.WriterClient.doSend(WriterClient.java:216)
	at org.apache.fluss.client.write.WriterClient.send(WriterClient.java:139)
	at org.apache.fluss.client.table.writer.AbstractTableWriter.send(AbstractTableWriter.java:66)
	at org.apache.fluss.client.table.writer.AppendWriterImpl.append(AppendWriterImpl.java:87)
	at org.apache.fluss.flink.sink.writer.AppendSinkWriter.writeRow(AppendSinkWriter.java:62)
	at org.apache.fluss.flink.sink.writer.FlinkSinkWriter.write(FlinkSinkWriter.java:143)
	... 14 more
Caused by: java.lang.NullPointerException
	at org.apache.fluss.cluster.Cluster.getBucketCount(Cluster.java:177)
	at org.apache.fluss.client.write.StickyBucketAssigner.nextBucket(StickyBucketAssigner.java:76)
	at org.apache.fluss.client.write.StickyBucketAssigner.assignBucket(StickyBucketAssigner.java:50)
	at org.apache.fluss.client.write.DynamicBucketAssigner.assignBucket(DynamicBucketAssigner.java:32)
	at org.apache.fluss.client.write.StickyBucketAssigner.assignBucket(StickyBucketAssigner.java:34)
	at org.apache.fluss.client.write.WriterClient.doSend(WriterClient.java:189)
	... 19 more

Solution

No response

Are you willing to submit a PR?

• I'm willing to submit a PR!