mysql> alter table sbtest1 drop column cityname2;


ERROR 1114 (HY000): The table 'sbtest1' is full
mysql> 
Error reported while doing sysbench stress test.
Reason.
It is known that the size of the memory table exceeds the specified range. After reviewing the default value of both is 16M.
Need to set tmp_table_size greater than or equal tomax_heap_table_size。
mysql> show variables like '%table_size%';
+---------------------+----------+
| Variable_name       | Value    |
+---------------------+----------+
| max_heap_table_size | 16777216 |
| tmp_table_size      | 16777216 |
+---------------------+----------+
2 rows in set (0.00 sec)
Neither of them support dynamic modification, and the modification will not take effect.
[mysqld]
max_heap_table_size           =32M
tmp_table_size                =64M

# /etc/init.d/mysql restart
Shutting down MySQL.. SUCCESS! 
Starting MySQL.. SUCCESS! 
mysql> show variables like '%table_size%';
+---------------------+----------+
| Variable_name       | Value    |
+---------------------+----------+
| max_heap_table_size | 33554432 |
| tmp_table_size      | 67108864 |
+---------------------+----------+
2 rows in set (0.01 sec)
You can see the modified parameters take effect after the reboot.
Then just perform the operation to delete the field.