1.
User can export query result to local disk like:
`select * from tbl into outfile ("file:///disk1/result_");`
And modify the return result to show the details of export:
```
mysql> select * from tbl1 limit 10 into outfile "file:///home/work/path/result_";
+------------+-----------+----------+--------------+
| FileNumber | TotalRows | FileSize | URL |
+------------+-----------+----------+--------------+
| 1 | 2 | 8 | 192.168.1.10 |
+------------+-----------+----------+--------------+
```
2.
Support create a mark file after export successfully finished.
Co-authored-by: chenmingyu <chenmingyu@baidu.com>
4b316e4c3f