select collation(user()) get wrong result.

[wjhuang2016]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do?

mysql> select collation(user());

+-------------------+
| collation(user()) |
+-------------------+
|                   |
+-------------------+
1 row in set (0.00 sec)

besides:

mysql> select collation(compress('abc'));
+--------------------------------------------------------+
| collation(compress('abc'))                             |
+--------------------------------------------------------+
| 0x62696E617279                                         |
+--------------------------------------------------------+
1 row in set (0.00 sec)

These results are all wrong.

4. What version of TiDB are you using? (tidb-server -V or run select tidb_version(); on TiDB)

master