当我尝试向表中添加主键时出现此错误
lost connection to mysql server during query，这是我的查询：
ALTER TABLE test ADD PRIMARY KEY (ORDER_ID);
我的数据库配置超时：
+----------------------------+----------+
| Variable_name | Value |
+----------------------------+----------+
| connect_timeout | 10 |
| delayed_insert_timeout | 300 |
| innodb_lock_wait_timeout | 50 |
| innodb_rollback_on_timeout | OFF |
| interactive_timeout | 28800 |
| lock_wait_timeout | 31536000 |
| net_read_timeout | 30 |
| net_write_timeout | 60 |
| slave_net_timeout | 3600 |
| thread_pool_idle_timeout | 60 |
| wait_timeout | 28800 |
+----------------------------+----------+