@Override
  public SettableFuture<ConfigTaskResult> showClusterParameters() {
    final SettableFuture<ConfigTaskResult> future = SettableFuture.create();
    TShowVariablesResp showVariablesResp = new TShowVariablesResp();
    try (final ConfigNodeClient client =
        CONFIG_NODE_CLIENT_MANAGER.borrowClient(ConfigNodeInfo.CONFIG_REGION_ID)) {
      showVariablesResp = client.showVariables();
    } catch (ClientManagerException | TException e) {
      future.setException(e);
    }

    // build TSBlock
    ShowVariablesTask.buildTSBlock(showVariablesResp, future);

    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