Hello all: I could really using Flink 1.20 with Flink CDC 3.3, deployed on a Kubernetes cluster, to synchronize data from MySQL to StarRocks. Both the source table (

test.vip_record

) and the sink table (

test.ods_vip_record

) currently have exactly the same schema, and no DDL changes have been made during the job execution. However, the job keeps failing after running for some time, and the logs show the following error:

2025-11-14 20:32:03
java.lang.IllegalStateException: Unable to coerce data record from test.vip_record (schema: null) to test.ods_vip_record (schema: null)
  at org.apache.flink.cdc.runtime.operators.schema.regular.SchemaOperator.lambda$handleDataChangeEvent$1(SchemaOperator.java:235)
  at java.util.Optional.orElseThrow(Optional.java:290)
  at org.apache.flink.cdc.runtime.operators.schema.regular.SchemaOperator.handleDataChangeEvent(SchemaOperator.java:232)
  at org.apache.flink.cdc.runtime.operators.schema.regular.SchemaOperator.processElement(SchemaOperator.java:152)
  at org.apache.flink.streaming.runtime.tasks.CopyingChainingOutput.pushToOperator(CopyingChainingOutput.java:75)
  at org.apache.flink.streaming.runtime.tasks.CopyingChainingOutput.collect(CopyingChainingOutput.java:50)
  at org.apache.flink.streaming.runtime.tasks.CopyingChainingOutput.collect(CopyingChainingOutput.java:29)
  at org.apache.flink.streaming.runtime.tasks.SourceOperatorStreamTask$AsyncDataOutputToOutput.emitRecord(SourceOperatorStreamTask.java:310)
  at org.apache.flink.streaming.api.operators.source.SourceOutputWithWatermarks.collect(SourceOutputWithWatermarks.java:110)
  at org.apache.flink.streaming.api.operators.source.SourceOutputWithWatermarks.collect(SourceOutputWithWatermarks.java:101)
  at org.apache.flink.cdc.connectors.mysql.source.reader.MySqlRecordEmitter$OutputCollector.collect(MySqlRecordEmitter.java:141)
  at java.util.Collections$SingletonList.forEach(Collections.java:4824)
  at org.apache.flink.cdc.debezium.event.DebeziumEventDeserializationSchema.deserialize(DebeziumEventDeserializationSchema.java:93)
  at org.apache.flink.cdc.connectors.mysql.source.reader.MySqlRecordEmitter.emitElement(MySqlRecordEmitter.java:119)
  at org.apache.flink.cdc.connectors.mysql.source.reader.MySqlRecordEmitter.processElement(MySqlRecordEmitter.java:101)
  at org.apache.flink.cdc.connectors.mysql.source.reader.MySqlPipelineRecordEmitter.processElement(MySqlPipelineRecordEmitter.java:120)
  at org.apache.flink.cdc.connectors.mysql.source.reader.MySqlRecordEmitter.emitRecord(MySqlRecordEmitter.java:73)
  at org.apache.flink.cdc.connectors.mysql.source.reader.MySqlRecordEmitter.emitRecord(MySqlRecordEmitter.java:46)
  at org.apache.flink.connector.base.source.reader.SourceReaderBase.pollNext(SourceReaderBase.java:203)
  at org.apache.flink.streaming.api.operators.SourceOperator.emitNext(SourceOperator.java:422)
  at org.apache.flink.streaming.runtime.io.StreamTaskSourceInput.emitNext(StreamTaskSourceInput.java:68)
  at org.apache.flink.streaming.runtime.io.StreamOneInputProcessor.processInput(StreamOneInputProcessor.java:65)
  at org.apache.flink.streaming.runtime.tasks.StreamTask.processInput(StreamTask.java:638)
  at org.apache.flink.streaming.runtime.tasks.mailbox.MailboxProcessor.runMailboxLoop(MailboxProcessor.java:231)
  at org.apache.flink.streaming.runtime.tasks.StreamTask.runMailboxLoop(StreamTask.java:973)
  at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:917)
  at org.apache.flink.runtime.taskmanager.Task.runWithSystemExitMonitoring(Task.java:970)
  at org.apache.flink.runtime.taskmanager.Task.restoreAndInvoke(Task.java:949)
  at org.apache.flink.runtime.taskmanager.Task.doRun(Task.java:763)
  at org.apache.flink.runtime.taskmanager.Task.run(Task.java:575)
  at java.lang.Thread.run(Thread.java:750)

The key part is:

schema: null

which suggests that both the source and sink schemas are unexpectedly lost or not recognized during the runtime. --- ### Additional information * Deployment mode: Flink on Kubernetes (Native K8s Mode) * Source: MySQL 5.7 * Sink: StarRocks * Flink CDC performs snapshot + incremental reading normally after restart * After 1–2 hours of normal running, the job fails with the above error * No schema changes were made during this time --- ### Questions 1. Under what conditions would

SchemaOperator

encounter

(schema: null)

for both source and sink? 2. Could this be related to state inconsistency or schema metadata loss inside checkpoint/savepoint? 3. Is this a known issue in Flink CDC 3.3 with Flink 1.20? 4. Are there recommended configurations to ensure stable schema management for MySQL → StarRocks pipelines? Thank you!

I have a similar issue, but the sink is paimon. Did you ever figure out the problem?