@org.apache.thrift.annotation.Nullable
    public static _Fields findByThriftId(int fieldId) {
      switch(fieldId) {
        case 1: // DBNAME
          return DBNAME;
        case 2: // TBLNAME
          return TBLNAME;
        case 3: // PARTITIONNAME
          return PARTITIONNAME;
        case 4: // TYPE
          return TYPE;
        case 5: // METRICVALUE
          return METRICVALUE;
        case 6: // VERSION
          return VERSION;
        case 7: // THRESHOLD
          return THRESHOLD;
        default:
          return null;
      }
    }
Find the _Fields constant that matches fieldId, or null if its not found.
standalone-metastore/metastore-common/src/gen/thrift/gen-javabean/org/apache/hadoop/hive/metastore/api/CompactionMetricsDataStruct.java