After I sought help from the official Doris community（slack:https://join.slack.com/t/apachedoriscommunity/shared_invite/zt-28il1o2wk-DD6LsLOz3v4aD92Mu0S0aQ）, they described it as a known issue that had been fixed. Moreover, my cluster version was not 2.1 but an old 1.0 version. I solved this problem by upgrading to the new version。