mysql学习记录（二十）--MysqlServer参数调整(三)
-----------+
4 rows in set (0.00 sec)
mysql> set global key_cache_division_limit = 70;
Query OK, 0 rows affected (0.00 sec)
mysql> set global hot_cache.key_cache_division_limit = 70;
Query OK, 0 rows affected (0.00 sec)
mysql> show global variables like '%innodb_old_blocks_pct%';
+-----------------------+-------+
| Variable_name | Value |
+-----------------------+-------+
| innodb_old_blocks_pct | 37 |
+-----------------------+-------+
1 row in set (0.01 sec)
mysql> show global variables like '%doublewrirte%';
Empty set (0.00 sec)
mysql> show global variables like '%doublewrite%';
+--------------------+-------+
| Variable_name | Value |
+--------------------+-------+
| innodb_doublewrite | ON |
+--------------------+-------+
1 row in set (0.01 sec)
mysql>
select @a1 := variable_value as a1;
ERROR 1054 (42S22): Unknown column 'variable_value' in 'field list'
mysql> select @a1 := variable_value as a1
-> from information_schema.global_status
-> where variable_name = 'innodb_os_log_written'
-> union all
-> select sleep(60)
-> union all
-> select @a2 := variable_value as a2
-> from information_schema.global_status
-> where variable_name = 'innodb_os_log_written';
+------+
| a1 |
+------+
| 9216 |
| 0 |
| 9216 |
+------+
3 rows in set (1 min 0.02 sec)
mysql> select round((@a2-@a1)/1024/1024 / @@innodb_log_files_in_group) as MB;
+------+
| MB |
+------+
| 0 |
+------+
1 row in set (0.01 sec)