# Confluent Managed ClickHouse does not handle fields in protobuf one\_of well **URL:** \ **Category:** Managed Connectors\ **Created:** [18 July 2025 01:32 UTC](https://forum.confluent.io/t/confluent-managed-clickhouse-does-not-handle-fields-in-protobuf-one-of-well/37985 "2025-07-18T01:32:11Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![shriramholla](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.confluent.io/shriramholla/32/5135_2.png) [@shriramholla](https://forum.confluent.io/u/shriramholla)\ **Post date:** [18 July 2025 01:32 UTC](https://forum.confluent.io/t/confluent-managed-clickhouse-does-not-handle-fields-in-protobuf-one-of-well/37985/1 "2025-07-18T01:32:11Z")
Hello, I am trying to insert protobuf serialized messages from a topic with a schema to ClickHouse. I am using the confluent managed clickhouse connector with the following settings: | Table Refresh Interval | 0 | | --- | --- | | Bypass RowBinary | true | | Exactly Once | false | | Error Tolerance | none | | Enable DLQ Context Headers | false | | ClickHouse Settings | input\_format\_binary\_read\_json\_as\_string=1 | | Tolerate State Mismatch | false | | value.converter.decimal.format | BASE64 | | value.converter.replace.null.with.default | false | | value.converter.reference.subject.name.strategy | DefaultReferenceSubjectNameStrategy | | value.converter.schemas.enable | false | | value.converter.value.subject.name.strategy | TopicNameStrategy | | key.converter.key.subject.name.strategy | TopicNameStrategy | | value.converter.ignore.default.for.nullables | true | | Enable Connector Auto-restart | true | | Schema context | default | | Max poll interval(ms) | 60000 | | Input Kafka record key format | JSON | | Max poll records | 5000 | My protobuf schema, while being quite large has “oneof” properties. It appears that the connector does not handle these fields well as I receive this error: org.apache.kafka.connect.errors.ConnectException: Exiting WorkerSinkTask due to unrecoverable exception. at org.apache.kafka.connect.runtime.WorkerSinkTask.deliverMessages(WorkerSinkTask.java:787) at org.apache.kafka.connect.runtime.WorkerSinkTask.poll(WorkerSinkTask.java:379) at org.apache.kafka.connect.runtime.WorkerSinkTask.iteration(WorkerSinkTask.java:270) at org.apache.kafka.connect.runtime.WorkerSinkTask.execute(WorkerSinkTask.java:239) at org.apache.kafka.connect.runtime.WorkerTask.doRun(WorkerTask.java:272) at org.apache.kafka.connect.runtime.WorkerTask.run(WorkerTask.java:328) at org.apache.kafka.connect.runtime.isolation.Plugins.lambda$withClassLoader$7(Plugins.java:341) at java.base/java.util.concurrent.Executors$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$Worker.run(ThreadPoolExecutor.java:642) at java.base/java.lang.Thread.run(Thread.java:1583) Caused by: java.lang.RuntimeException: Number of records: 3190 at com.clickhouse.kafka.connect.util.Utils.handleException(Utils.java:122) at com.clickhouse.kafka.connect.sink.ClickHouseSinkTask.put(ClickHouseSinkTask.java:56) at org.apache.kafka.connect.runtime.WorkerSinkTask.deliverMessages(WorkerSinkTask.java:753) … 11 more Caused by: java.lang.RuntimeException: Topic: [analytics\_events\_v2], Partition: [11], MinOffset: [1883872], MaxOffset: [1887061], (QueryId: [37b0ab24-32e2-4535-bcd3-41bd9c81c3b2]) at com.clickhouse.kafka.connect.sink.processing.Processing.doInsert(Processing.java:57) at com.clickhouse.kafka.connect.sink.processing.Processing.doLogic(Processing.java:143) at com.clickhouse.kafka.connect.sink.ProxySinkTask.put(ProxySinkTask.java:102) at com.clickhouse.kafka.connect.sink.ClickHouseSinkTask.put(ClickHouseSinkTask.java:48) … 12 more Caused by: java.lang.IllegalArgumentException: Class io.confluent.connect.protobuf.ProtobufData$SchemaWrapper declares multiple JSON fields named ‘parameters’; conflict is caused by fields io.confluent.connect.protobuf.ProtobufData$SchemaWrapper#parameters and org.apache.kafka.connect.data.SchemaBuilder#parameters See [gson/Troubleshooting.md at 3488c30c65afb7bc3715c68b2a4f10ca2500c821 · google/gson · GitHub](https://github.com/google/gson/blob/3488c30c65afb7bc3715c68b2a4f10ca2500c821/Troubleshooting.md#duplicate-fields) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.createDuplicateFieldException(ReflectiveTypeAdapterFactory.java:313) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:409) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:161) at com.google.gson.Gson.getAdapter(Gson.java:628) at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:57) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$2.write(ReflectiveTypeAdapterFactory.java:247) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:490) at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:73) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$2.write(ReflectiveTypeAdapterFactory.java:247) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:490) at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:73) at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:99) at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:59) at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:73) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$2.write(ReflectiveTypeAdapterFactory.java:247) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:490) at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:73) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$2.write(ReflectiveTypeAdapterFactory.java:247) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:490) at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:73) at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:99) at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:59) at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:73) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$2.write(ReflectiveTypeAdapterFactory.java:247) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:490) at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:73) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$2.write(ReflectiveTypeAdapterFactory.java:247) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:490) at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:73) at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:99) at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:59) at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:73) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$2.write(ReflectiveTypeAdapterFactory.java:247) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:490) at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:73) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$2.write(ReflectiveTypeAdapterFactory.java:247) at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:490) at com.google.gson.internal.bind.ObjectTypeAdapter.write(ObjectTypeAdapter.java:184) at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:73) at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.write(MapTypeAdapterFactory.java:222) at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.write(MapTypeAdapterFactory.java:154) at com.google.gson.Gson.toJson(Gson.java:944) at com.google.gson.Gson.toJson(Gson.java:899) at com.google.gson.Gson.toJson(Gson.java:848) at com.clickhouse.kafka.connect.sink.db.ClickHouseWriter.doInsertJsonV1(ClickHouseWriter.java:896) at com.clickhouse.kafka.connect.sink.db.ClickHouseWriter.doInsertJson(ClickHouseWriter.java:846) at com.clickhouse.kafka.connect.sink.db.ClickHouseWriter.doInsert(ClickHouseWriter.java:202) at com.clickhouse.kafka.connect.sink.processing.Processing.doInsert(Processing.java:55)