Start error reporting from savePoint after modifying the number of keyby fields (from the previous three keys to the present four keys)

java.lang.Exception: Exception while creating StreamOperatorStateContext.

at org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.streamOperatorStateContext(StreamTaskStateInitializerImpl.java:192)

at org.apache.flink.streaming.api.operators.AbstractStreamOperator.initializeState(AbstractStreamOperator.java:227)

at org.apache.flink.streaming.runtime.tasks.StreamTask.initializeState(StreamTask.java:738)

at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:289)

at org.apache.flink.runtime.taskmanager.Task.run(Task.java:711)

at java.lang.Thread.run(Thread.java:748)

Caused by: org.apache.flink.util.FlinkException: Could not restore keyed state backend for StreamFlatMap_16b166ecf5d9fd813aab48502efdb6f5_(1/1) from any of the 1 provided restore options.

at org.apache.flink.streaming.api.operators.BackendRestorerProcedure.createAndRestore(BackendRestorerProcedure.java:137)

at org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.keyedStatedBackend(StreamTaskStateInitializerImpl.java:279)

at org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.streamOperatorStateContext(StreamTaskStateInitializerImpl.java:133)

... 5 more

Caused by: org.apache.flink.util.StateMigrationException: The new key serializer is not compatible to read previous keys. Aborting now s*******ate migration is currently not available

at org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend$RocksDBFullRestoreOperation.restoreKVStateMetaData(RocksDBKeyedStateBackend.java:689)

at org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend$RocksDBFullRestoreOperation.restoreKeyGroupsInStateHandle(RocksDBKeyedStateBackend.java:652)

at org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend$RocksDBFullRestoreOperation.doRestore(RocksDBKeyedStateBackend.java:638)

at org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend.restore(RocksDBKeyedStateBackend.java:525)

at org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend.restore(RocksDBKeyedStateBackend.java:166)

at org.apache.flink.streaming.api.operators.BackendRestorerProcedure.attemptCreateAndRestore(BackendRestorerProcedure.java:151)

at org.apache.flink.streaming.api.operators.BackendRestorerProcedure.createAndRestore(BackendRestorerProcedure.java:123)

... 7 more