@Override
  public String toString() {
    return String.format(
        "Query[%s]-[%s-%s-SinkChannel]:",
        localFragmentInstanceId.queryId,
        localFragmentInstanceId.fragmentId,
        localFragmentInstanceId.instanceId);
  }
max bytes this SinkChannel can reserve.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/exchange/sink/SinkChannel.java