@Override
  public SettableFuture<ConfigTaskResult> showTopics(
      final ShowTopicsStatement showTopicsStatement) {
    final SettableFuture<ConfigTaskResult> future = SettableFuture.create();
    try (final ConfigNodeClient configNodeClient =
        CONFIG_NODE_CLIENT_MANAGER.borrowClient(ConfigNodeInfo.CONFIG_REGION_ID)) {
      final TShowTopicReq showTopicReq = new TShowTopicReq();
      if (showTopicsStatement.getTopicName() != null) {
        showTopicReq.setTopicName(showTopicsStatement.getTopicName());
      }
      showTopicReq.setIsTableModel(showTopicsStatement.isTableModel());

      final TShowTopicResp showTopicResp = configNodeClient.showTopic(showTopicReq);
      if (showTopicResp.getStatus().getCode() != TSStatusCode.SUCCESS_STATUS.getStatusCode()) {
        future.setException(
            new IoTDBException(
                showTopicResp.getStatus().getMessage(), showTopicResp.getStatus().getCode()));
        return future;
      }

      ShowTopicsTask.buildTSBlock(
          showTopicResp.isSetTopicInfoList()
              ? showTopicResp.getTopicInfoList()
              : Collections.emptyList(),
          future);
    } catch (final Exception e) {
      future.setException(e);
    }
    return future;
  }
FIXME Consolidate this clientManager with the upper one.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/execution/config/executor/ClusterConfigTaskExecutor.java