Description:
When table_name includes "must quoted characters" - Except of ASCII: [0-9,a-z,A-Z$_] (basic Latin letters, digits 0-9, dollar, underscore) -,
https://dev.mysql.com/doc/refman/8.0/en/identifiers.html
SET GLOBAL innodb_ft_aux_table = "table_name" fails because "must quoted characters" are converted at table creation time but SET GLOBAL statement doesn't convert table_name.
How to repeat:
mysql> CREATE TABLE `t-1` (val varchar(32), FULLTEXT KEY(val));
Query OK, 0 rows affected (0.05 sec)
mysql> SET GLOBAL innodb_ft_aux_table = 'd1/t-1';
ERROR 1231 (42000): Variable 'innodb_ft_aux_table' can't be set to the value of 'd1/t-1'
mysql> SELECT table_id, name FROM information_schema.innodb_tables WHERE name LIKE 'd1/%';
+----------+--------------------------------------------------+
| table_id | name |
+----------+--------------------------------------------------+
| 1222 | d1/t@002d1 | <-- "-" is converted to "@002d"
| 1223 | d1/fts_00000000000004c6_being_deleted |
| 1224 | d1/fts_00000000000004c6_being_deleted_cache |
| 1225 | d1/fts_00000000000004c6_config |
| 1226 | d1/fts_00000000000004c6_deleted |
| 1227 | d1/fts_00000000000004c6_deleted_cache |
| 1228 | d1/fts_00000000000004c6_00000000000001da_index_1 |
| 1229 | d1/fts_00000000000004c6_00000000000001da_index_2 |
| 1230 | d1/fts_00000000000004c6_00000000000001da_index_3 |
| 1231 | d1/fts_00000000000004c6_00000000000001da_index_4 |
| 1232 | d1/fts_00000000000004c6_00000000000001da_index_5 |
| 1233 | d1/fts_00000000000004c6_00000000000001da_index_6 |
+----------+--------------------------------------------------+
12 rows in set (0.00 sec)
mysql> SET GLOBAL innodb_ft_aux_table = 'd1/t@002d1';
Query OK, 0 rows affected (0.00 sec)
Suggested fix:
Convert "must quoted characters" as same as table creation time (sql/strfunc.cc:strconvert)
At least, this limitation should be documented.
