TokuDB Hot Column Expansion I need to expand a varchar field length from 255 to 4000.

I am using tokudb_version: tokudb-7.5.8 running on Linux 3.16.0-60-generic #80~14.04.1-Ubuntu SMP Wed Jan 20 13:37:48 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

I know TokuDB supports Hot Column operations but this is not working for me ( number of rows ~ 210 million)

Show variables file: https://drive.google.com/file/d/0B5noFLrbjDjzSW9wdnVjb095Q0U/view?usp=sharing

Alter command 

alter table test_table modify test_column varchar(4000);

Show processlist:
mysql&gt; show processlist;
+----+------+-----------+---------------+---------+------+---------------------------------------------------------+------------------------------------------------------------+-----------+---------------+
| Id | User | Host      | db            | Command | Time | State                                                   | Info                                                       | Rows_sent | Rows_examined |
+----+------+-----------+---------------+---------+------+---------------------------------------------------------+------------------------------------------------------------+-----------+---------------+
|  6 | root | localhost | NULL          | Query   |    0 | init                                                    | show processlist                                           |         0 |             0 |
|  7 | root | localhost | test | Query   |  461 | Queried about 2445001 rows, Inserted about 2445000 rows | alter table test_table modify test_column varchar(4000) |         0 |             0 |
+----+------+-----------+---------------+---------+------+---------------------------------------------------------+------------------------------------------------------------+-----------+---------------+
2 rows in set (0.00 sec)


Any idea which options I might need to set because it's currently processing at ~ 6k per second(which might take me ~10 hours)
If you only want online operations you should consider setting tokudb_disable_slow_alter=ON as per https://www.percona.com/doc/percona-server/5.7/tokudb/tokudb_variables.html#tokudb_disable_slow_alter.