{"record":{"id":"b41ba14b325f8943","repo":"apache/flink","slug":"could-not-serialize-row-s","errorCode":null,"errorMessage":"Could not serialize row '%s'.","messagePattern":"Could not serialize row '(.+?)'\\.","errorType":"exception","errorClass":"RuntimeException","httpStatus":null,"severity":"error","filePath":"flink-formats/flink-avro-confluent-registry/src/main/java/org/apache/flink/formats/avro/registry/confluent/debezium/DebeziumAvroSerializationSchema.java","lineNumber":129,"sourceCode":"                case UPDATE_AFTER:\n                    outputReuse.setField(0, null);\n                    outputReuse.setField(1, rowData);\n                    outputReuse.setField(2, OP_INSERT);\n                    return avroSerializer.serialize(outputReuse);\n                case UPDATE_BEFORE:\n                case DELETE:\n                    outputReuse.setField(0, rowData);\n                    outputReuse.setField(1, null);\n                    outputReuse.setField(2, OP_DELETE);\n                    return avroSerializer.serialize(outputReuse);\n                default:\n                    throw new UnsupportedOperationException(\n                            format(\n                                    \"Unsupported operation '%s' for row kind.\",\n                                    rowData.getRowKind()));\n            }\n        } catch (Throwable t) {\n            throw new RuntimeException(format(\"Could not serialize row '%s'.\", rowData), t);\n        }\n    }\n\n    @Override\n    public boolean equals(Object o) {\n        if (this == o) {\n            return true;\n        }\n        if (o == null || getClass() != o.getClass()) {\n            return false;\n        }\n        DebeziumAvroSerializationSchema that = (DebeziumAvroSerializationSchema) o;\n        return Objects.equals(avroSerializer, that.avroSerializer);\n    }\n\n    @Override\n    public int hashCode() {\n        return Objects.hash(avroSerializer);","sourceCodeStart":111,"sourceCodeEnd":147,"githubUrl":"https://github.com/apache/flink/blob/2f3c205e9266cb30240eb7f4fdab15cad629a70f/flink-formats/flink-avro-confluent-registry/src/main/java/org/apache/flink/formats/avro/registry/confluent/debezium/DebeziumAvroSerializationSchema.java#L111-L147","documentation":"Outer catch in DebeziumAvroSerializationSchema.serialize(): any Throwable raised while building the Debezium envelope GenericRecord or running the Avro serializer is re-thrown as RuntimeException(\"Could not serialize row '%s'.\"). The offending RowData is rendered into the message and the root cause is attached; diagnose via the cause, not the wrapper text.","triggerScenarios":"Type mismatches between the RowData and the Avro schema used by avroSerializer (e.g. string vs bytes), nulls written into non-nullable envelope fields, Avro registry client failures during schema registration, or the unsupported-RowKind UnsupportedOperationException (error 1325) bubbling up as the cause.","commonSituations":"DDL columns whose types drift from the registered subject schema; registry auth (basic/bearer) misconfigured so schema registration fails on first serialize; nulls in key columns.","solutions":["Inspect getCause() — fix whichever nested exception (UnsupportedOperationException, AvroTypeException, RestServiceException) is the real failure.","If the cause is the RowKind error, normalize kinds as per error 1325.","Verify the registry URL/credentials from TaskManagers: curl http://<registry>/subjects and confirm the subject is writable.","Reconcile table DDL with the target Avro schema (types and nullability of before/after)."],"exampleFix":null,"handlingStrategy":"try-catch","validationCode":null,"typeGuard":null,"tryCatchPattern":"catch (RuntimeException e) { Throwable root = deepest(e); if (root instanceof RestServiceException) retry/alert registry; else if (root instanceof UnsupportedOperationException) fix row kind; else surface row from message to DLQ; }","preventionTips":["Unit-test serialize() with representative rows (nulls, all kinds) before deploying","Verify registry credentials with curl before job start","Keep table DDL and Avro schema in sync via schema-registry CI checks"],"tags":["debezium","avro","wrapper-exception","serialization","diagnostics"],"backgroundTag":null,"analyzedSha":"2f3c205e9266cb30240eb7f4fdab15cad629a70f","analyzedAt":"2026-08-14T08:48:24.518Z","schemaVersion":2},"datasetVersion":"2026-08-14T10:17:34.591Z"}