query use orderDesc is very slower than order

android 8.0 huawei P9
objectVersion：2.4.0

I inserted 12w pieces of data into Message table

@Entity
public class Message implements Serializable {

   @Id
    public long id;

    @Index
    private long serverId; 

    @Index
    private String sid;
    .......

}

the query method：

private void queryTest() {
       queryTest(1);
        queryTest(10);
        queryTest(50);
        queryTest(100);
        queryTest(1000);
        queryTest(3000);
        queryTest(6000);
        queryTest(10000);
}

private void queryTest(int queryNum) {
        long time = SystemClock.uptimeMillis();
        List<Message> messageList = Message.getMessageListByServerID2("k-007-liushengyun", Long.MIN_VALUE, queryNum);
        Log.d(TAG, "queryTest queryNum =" + queryNum + ",size=" + messageList.size() + ",orderTime=" + (SystemClock.uptimeMillis() - time));
        time = SystemClock.uptimeMillis();
        messageList = Message.getMessageListByServerID3("k-007-liushengyun", Long.MIN_VALUE, queryNum);
        Log.d(TAG, "queryTest queryNum =" + queryNum + ",size=" + messageList.size() + ",orderDescTime=" + (SystemClock.uptimeMillis() - time));
        messageList.clear();
    }

public static List<Message> getMessageListByServerID2(String sid, long minServerID, int count) {
        try {
            Query<Message> query = StoreManager.getBoxStore().boxFor(Message.class).query()
                    .equal(Message_.sid, sid)
                    .greater(Message_.serverId, minServerID).or().equal(Message_.serverId, minServerID)
                    .order(Message_.serverId).build();
            return count > 0 ? query.find(0, count) : query.find();
        } catch (Exception e) {
            SogouPlus.onException(e);
            return new LinkedList<>();
        }
    }

public static List<Message> getMessageListByServerID3(String sid, long minServerID, int count) {
        try {
            Query<Message> query = StoreManager.getBoxStore().boxFor(Message.class).query()
                    .equal(Message_.sid, sid)
                    .greater(Message_.serverId, minServerID).or().equal(Message_.serverId, minServerID)
                    .orderDesc(Message_.serverId).build();
            return count > 0 ? query.find(0, count) : query.find();
        } catch (Exception e) {
            SogouPlus.onException(e);
            return new LinkedList<>();
        }
    }

the query result:(ms)

queryTest queryNum =1,size=1,orderTime=71
queryTest queryNum =1,size=1,orderDescTime=301
queryTest queryNum =10,size=10,orderTime=72
queryTest queryNum =10,size=10,orderDescTime=581
queryTest queryNum =50,size=50,orderTime=73
queryTest queryNum =50,size=50,orderDescTime=908
queryTest queryNum =100,size=100,orderTime=75
queryTest queryNum =100,size=100,orderDescTime=1079
queryTest queryNum =1000,size=1000,orderTime=114
queryTest queryNum =1000,size=1000,orderDescTime=1952
queryTest queryNum =3000,size=3000,orderTime=175
queryTest queryNum =3000,size=3000,orderDescTime=2504
queryTest queryNum =6000,size=6000,orderTime=293
queryTest queryNum =6000,size=6000,orderDescTime=2846
queryTest queryNum =10000,size=10000,orderTime=483
queryTest queryNum =10000,size=10000,orderDescTime=3123

Start with the reported getMessageListByServerID2 and getMessageListByServerID3 methods, then reproduce queryTest on Android 8.0 with the 120,000-row Message dataset. Compare order and orderDesc timings and results; done means the descending-query behavior is explained or corrected and covered by a regression check.