In recent ClickHouse versions (21.3) Avro format for kafka does not work at all.
In ClickHouse 20.3 one Avro formatted kafka message can read, than stall forever.
Reportedly in ClickHouse prior 20.3 Avro formatted kafka messages work Ok while contain only single record
: type(type_)
            , actions(actions_) {}
    };
    
    AvroDeserializer::Action createAction(const Block & header, const avro::NodePtr & node, const std::string & current_path = "");
    
    std::vector<bool> column_found;
    
    Action row_action;
    
    
    std::map<avro::Name, SkipFn> symbolic_skip_fn_map;
};
class AvroRowInputFormat : public IRowInputFormat
{
public:
    AvroRowInputFormat(const Block & header_, ReadBuffer & in_, Params params_, const FormatSettings & format_settings_);
    virtual bool readRow(MutableColumns & columns, RowReadExtension & ext) override;
    String getName() const override { return "AvroRowInputFormat"; }
private:
    avro::DataFileReaderBase file_reader;
    AvroDeserializer deserializer;
};
class AvroConfluentRowInputFormat : public IRowInputFormat