Change default internal sorting direction in CS

MariaDB [tpch1c]> use cs;

Database changed

MariaDB [cs]> use test

Database changed

MariaDB [test]> create table cs1(i int) engine=columnstore;

insQuery OK, 0 rows affected (2.71 sec)

create table in1(i int) engine=innodb;

MariaDB [test]> insert into cs1 values (4),(15);

Query OK, 2 rows affected (0.59 sec)

Records: 2  Duplicates: 0  Warnings: 0

insert into in1 values (4),(15);

MariaDB [test]> select * from cs1 order by i desc; -- This one uses server's filesort

+------+

| i    |

+------+

|   15 |

|    4 |

+------+

2 rows in set (0.13 sec)

MariaDB [test]> select * from (select * from cs1 order by i desc) t1; -- This one uses internal CS sorting

+------+

| i    |

+------+

|    4 |

|   15 |

+------+

2 rows in set (0.02 sec)