TokuDB热柱展开

Question

我需要将varchar字段长度从255扩展到4000。

我使用的是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

我知道TokuDB支持热列操作，但这并不适用于我(行数为2.1亿行)

显示变量文件：https://drive.google.com/file/d/0B5noFLrbjDjzSW9wdnVjb095Q0U/view?usp=sharing

Alter命令

alter table test_table modify test_column varchar(4000);

Show processlist:
mysql> 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)

知道我可能需要设置哪些选项，因为它目前正在以每秒~ 6k的速度处理(这可能要花我10个小时)

Answer 1

如果您只想要在线操作，您应该考虑根据tokudb_disable_slow_alter=ON设置https://www.percona.com/doc/percona-server/5.7/tokudb/tokudb_variables.html#tokudb_禁用_慢的_更改。