public static synchronized PipeConfigNodeSubtaskExecutor getInstance() {
    if (PipeSchemaSubtaskExecutorHolder.instance == null) {
      PipeSchemaSubtaskExecutorHolder.instance = new PipeConfigNodeSubtaskExecutor();
    }
    return PipeSchemaSubtaskExecutorHolder.instance;
  }
@param ignored Used to distinguish this constructor from the default constructor.
iotdb-core/confignode/src/main/java/org/apache/iotdb/confignode/manager/pipe/agent/task/PipeConfigNodeSubtaskExecutor.java