19.10. variables

show variables;
show global variables;
	

19.10.1. time_zone

		
SELECT @@global.time_zone, @@session.time_zone;			
		
		

19.10.2. sql_mode

19.10.2.1. 设置 sql_mode

SET GLOBAL sql_mode = 'NO_ENGINE_SUBSTITUTION';
SET SESSION sql_mode = 'NO_ENGINE_SUBSTITUTION';			
			

19.10.2.2. 查看 sql_mode

SELECT @@GLOBAL.sql_mode;
SELECT @@SESSION.sql_mode;
			

19.10.2.3. 兼容早起 MySQL 版本

导入数据库遇到这样的问题

[root@netkiller]/tmp# cat cms.sql| mysql -uroot -p cms
			

ERROR 1067 (42000) at line 2194: Invalid default value for 'created_date'

将下面代码加入到 cms.sql 头部可以解决

set @@global.sql_mode='NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION';
			

19.10.2.4. 5.7.16

			
mysql> select version();
+-----------+
| version() |
+-----------+
| 5.7.16    |
+-----------+
1 row in set (0.00 sec)

mysql> SELECT @@global.sql_mode;
+-------------------------------------------------------------------------------------------------------------------------------------------+
| @@global.sql_mode                                                                                                                         |
+-------------------------------------------------------------------------------------------------------------------------------------------+
| ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION |
+-------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
			
			

19.10.3. wait_timeout

		
mysql> show global variables like 'wait_timeout';
+----------------------------+-------+
| Variable_name              | Value |
+----------------------------+-------+
| wait_timeout               | 10    |
+----------------------------+-------+
		
		

		
mysql> use mysql;
Database changed

mysql> set wait_timeout=10;
Query OK, 0 rows affected (0.00 sec)

mysql> show variables  like '%wait_timeout%';
+--------------------------+-------+
| Variable_name            | Value |
+--------------------------+-------+
| innodb_lock_wait_timeout | 50    |
| table_lock_wait_timeout  | 50    |
| wait_timeout             | 10    |
+--------------------------+-------+
3 rows in set (0.00 sec)
		
		

19.10.4. table_lock_wait_timeout

		
mysql> set GLOBAL table_lock_wait_timeout=10;
Query OK, 0 rows affected (0.00 sec)

mysql> show variables  like '%table_lock_wait_timeout%';
+-------------------------+-------+
| Variable_name           | Value |
+-------------------------+-------+
| table_lock_wait_timeout | 10    |
+-------------------------+-------+
1 row in set (0.00 sec)
		
		

19.10.5. low_priority_updates

		
mysql> use mysql
Database changed

mysql> SET LOW_PRIORITY_UPDATES=1;
Query OK, 0 rows affected (0.00 sec)

mysql> show variables  like '%priority%';
+--------------------------+-------+
| Variable_name            | Value |
+--------------------------+-------+
| low_priority_updates     | ON    |
| sql_low_priority_updates | ON    |
+--------------------------+-------+
2 rows in set (0.00 sec)
		
		

19.10.6. character_set

		
mysql> show variables like 'character%';
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8                       |
| character_set_connection | utf8                       |
| character_set_database   | utf8                       |
| character_set_filesystem | binary                     |
| character_set_results    | utf8                       |
| character_set_server     | utf8                       |
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.00 sec)
		
		

19.10.7. datadir

 SHOW VARIABLES LIKE 'datadir';
		

		
mysql> SHOW VARIABLES LIKE 'datadir';
+---------------+-------------------------+
| Variable_name | Value                   |
+---------------+-------------------------+
| datadir       | /var/lib/mysql/         |
+---------------+-------------------------+
1 row in set (0.00 sec)
		
		

19.10.8. plugin_dir

show variables like '%plugin_dir%';

		
mysql> show variables like '%plugin_dir%';
+---------------+------------------------+
| Variable_name | Value                  |
+---------------+------------------------+
| plugin_dir    | /usr/lib/mysql/plugin/ |
+---------------+------------------------+
1 row in set (0.00 sec)
		
		

19.10.9. storage_engine

		
mysql> show variables like '%storage_engine%';
+------------------------+--------+
| Variable_name          | Value  |
+------------------------+--------+
| default_storage_engine | InnoDB |
| storage_engine         | InnoDB |
+------------------------+--------+
2 rows in set (0.00 sec)
		
		

19.10.10. timeout

show variables like "%timeout%";
		

19.10.11. max_connections

show variables like "max_connections";
		

set global max_connections = 200;
		

原文出处：Netkiller 系列 手札
本文作者：陈景峯
转载请与作者联系，同时请务必标明文章原始出处和作者信息及本声明。