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MySQL Server Configuration
可以在mysql_servers
表和mysql_replication_hostgroups
表(可选)中配置后端的MySQL Servers。
注意:在阅读下面内容之前,请确定你已经理解了ProxySQL中的多层次配置系统。
特别是:
- 修改
mysql_servers
表和mysql_replication_hostgroups
表后,在没有运行LOAD MYSQL SERVERS TO RUNTIME
时是不会生效的。 - 修改
mysql_servers
表和mysql_replication_hostgroups
表后,在没有运行SAVE MYSQL SERVERS TO DISK
时,ProxySQL的重启或崩溃都会丢失这些修改。**
也就是说,修改mysql_servers
和mysql_replication_hostgroups
表后,需要运行LOAD MYSQL SERVERS TO RUNTIME
才能让这些修改生效,需要运行SAVE MYSQL SERVERS TO DISK
才能持久化这些修改。
重要:下面的所有例子中,都需要执行LOAD MYSQL SERVERS TO RUNTIME
才生效,都需要执行SAVE MYSQL SERVERS TO DISK
才永久保存。
例如,要将MySQL Servers从内存数据库拷贝到runtime数据结构:
Admin> LOAD MYSQL SERVERS TO RUNTIME;
等价写法:
LOAD MYSQL SERVERS TO RUN
LOAD MYSQL SERVERS FROM MEM
LOAD MYSQL SERVERS FROM MEMORY
例如,要将MySQL Servers从内存数据库持久化到磁盘数据库:
Admin> SAVE MYSQL SERVERS TO DISK;
等价写法:
SAVE MYSQL SERVERS FROM MEM
SAVE MYSQL SERVERS FROM MEMORY
例如,将MySQL Servers从runtime数据结构拷贝到内存数据库:
Admin> SAVE MYSQL SERVERS TO MEMORY;
等价写法:
SAVE MYSQL SERVERS TO MEM
SAVE MYSQL SERVERS FROM RUN
SAVE MYSQL SERVERS FROM RUNTIME
例如,要将MySQL Servers从磁盘数据结构拷贝到内存数据库:
Admin> LOAD MYSQL SERVERS TO MEMORY;
等价写法:
LOAD MYSQL SERVERS TO MEM
LOAD MYSQL SERVERS FROM DISK
向mysql_servers
表中插入一个新行,就表示添加一个新的后端MySQL节点。
需要注意,这个表中有几个字段带有默认值属性。
例如,下面完全使用默认配置来添加一个后端节点:
Admin> SELECT * FROM mysql_servers;
Empty set (0.00 sec)
Admin> INSERT INTO mysql_servers (hostname) VALUES ('172.16.0.1');
Query OK, 1 row affected (0.00 sec)
Admin> SELECT * FROM mysql_servers\G
*************************** 1. row ***************************
hostgroup_id: 0
hostname: 172.16.0.1
port: 3306
status: ONLINE
weight: 1
compression: 0
max_connections: 1000
max_replication_lag: 0
use_ssl: 0
max_latency_ms: 0
comment:
1 row in set (0.00 sec)
(译注:可见,如果不需要将后端节点分组,添加时只需指定一个hostname字段即可。同时也发现,不指定主机组的后端,默认都属于id=0的主机组)
Admin> SELECT hostgroup_id,hostname FROM mysql_servers;
+--------------+------------+
| hostgroup_id | hostname |
+--------------+------------+
| 0 | 172.16.0.1 |
+--------------+------------+
1 row in set (0.00 sec)
Admin> INSERT INTO mysql_servers (hostgroup_id, hostname) VALUES (1, '172.16.0.2'), (1,'172.16.0.3');
Query OK, 2 rows affected (0.00 sec)
Admin> SELECT hostgroup_id,hostname FROM mysql_servers;
+--------------+------------+
| hostgroup_id | hostname |
+--------------+------------+
| 0 | 172.16.0.1 |
| 1 | 172.16.0.2 |
| 1 | 172.16.0.3 |
+--------------+------------+
3 rows in set (0.00 sec)
Admin> SELECT hostgroup_id,hostname,max_connections FROM mysql_servers;
+--------------+------------+-----------------+
| hostgroup_id | hostname | max_connections |
+--------------+------------+-----------------+
| 0 | 172.16.0.1 | 1000 |
| 1 | 172.16.0.2 | 1000 |
| 1 | 172.16.0.3 | 1000 |
+--------------+------------+-----------------+
3 rows in set (0.00 sec)
Admin> UPDATE mysql_servers SET max_connections=10 WHERE hostname='172.16.0.2';
Query OK, 1 row affected (0.00 sec)
Admin> SELECT hostgroup_id,hostname,max_connections FROM mysql_servers;
+--------------+------------+-----------------+
| hostgroup_id | hostname | max_connections |
+--------------+------------+-----------------+
| 0 | 172.16.0.1 | 1000 |
| 1 | 172.16.0.2 | 10 |
| 1 | 172.16.0.3 | 1000 |
+--------------+------------+-----------------+
3 rows in set (0.00 sec)
权重属性只在主机组中才有效。
Admin> SELECT hostgroup_id,hostname,weight FROM mysql_servers;
+--------------+------------+--------+
| hostgroup_id | hostname | weight |
+--------------+------------+--------+
| 0 | 172.16.0.1 | 1 |
| 1 | 172.16.0.2 | 1 |
| 1 | 172.16.0.3 | 1 |
+--------------+------------+--------+
3 rows in set (0.00 sec)
Admin> UPDATE mysql_servers SET weight=1000 WHERE hostname NOT IN ('172.16.0.2', '172.16.0.1') AND hostgroup_id=1;
Query OK, 1 row affected (0.00 sec)
Admin> SELECT hostgroup_id,hostname,weight FROM mysql_servers;
+--------------+------------+--------+
| hostgroup_id | hostname | weight |
+--------------+------------+--------+
| 0 | 172.16.0.1 | 1 |
| 1 | 172.16.0.2 | 1 |
| 1 | 172.16.0.3 | 1000 |
+--------------+------------+--------+
3 rows in set (0.00 sec)
下面的示例演示了如何配置和后端建立SSL连接。此处没有说明如何配置全局的SSL,全局SSL配置可参见此处。
Admin> SELECT hostgroup_id,hostname,use_ssl FROM mysql_servers;
+--------------+------------+---------+
| hostgroup_id | hostname | use_ssl |
+--------------+------------+---------+
| 0 | 172.16.0.1 | 1 |
| 1 | 172.16.0.2 | 0 |
| 1 | 172.16.0.3 | 0 |
+--------------+------------+---------+
3 rows in set (0.00 sec)
如果设置了某个节点的max_replication_lag
为非0值,则Monitor模块会对该节点是否拖后腿(replication lag)做常规检查。如果该字段设置为0,则Monitor模块不会做replication lag的检查。
Admin> SELECT hostgroup_id,hostname,max_replication_lag FROM mysql_servers;
+--------------+------------+---------------------+
| hostgroup_id | hostname | max_replication_lag |
+--------------+------------+---------------------+
| 0 | 172.16.0.1 | 0 |
| 1 | 172.16.0.2 | 0 |
| 1 | 172.16.0.3 | 0 |
+--------------+------------+---------------------+
3 rows in set (0.00 sec)
Admin> UPDATE mysql_servers SET max_replication_lag=30 WHERE hostname='172.16.0.3';
Query OK, 1 row affected (0.00 sec)
Admin> SELECT hostgroup_id,hostname,max_replication_lag FROM mysql_servers;
+--------------+------------+---------------------+
| hostgroup_id | hostname | max_replication_lag |
+--------------+------------+---------------------+
| 0 | 172.16.0.1 | 0 |
| 1 | 172.16.0.2 | 0 |
| 1 | 172.16.0.3 | 30 |
+--------------+------------+---------------------+
3 rows in set (0.00 sec)
上面的配置中,如果 172.16.0.3 相比master的数据延迟了30秒,则ProxySQL会暂时自动避开(忽略)该slave节点。
注意,如果将该字段设置为0,那么后端slave节点永远不会被自动避开,即使这个后端节点的复制线程工作不正常(译注:例如,SQL线程未开启,IO线程未开启,未连接上master等),详见:mysql-monitor_slave_lag_when_null。
mysql_servers
表的主键字段定义方式为PRIMARY KEY (hostgroup_id,hostname,port)
。这意味着同一个后端节点可以加入不同主机组中。
至于为什么要让一个节点加入多个组,有多种原因。例如,在一个复制拓扑结构中,有1个master节点,2个slave节点,你希望在slave故障时(例如它们宕机、或者拖后腿而被ProxySQL避开等)可以向master节点发送读请求。
(译注:为了让读尽量路由到slave上,可以将那个跨多组的节点(可能是master)在组中的权重设置的足够小)
一个示例:
Admin> SELECT hostgroup_id,hostname,weight,max_replication_lag FROM mysql_servers;
+--------------+------------+--------+---------------------+
| hostgroup_id | hostname | weight | max_replication_lag |
+--------------+------------+--------+---------------------+
| 0 | 172.16.0.1 | 1 | 0 |
| 1 | 172.16.0.2 | 1 | 0 |
| 1 | 172.16.0.3 | 1000 | 30 |
+--------------+------------+--------+---------------------+
3 rows in set (0.00 sec)
Admin> INSERT INTO mysql_servers(hostgroup_id,hostname) VALUES (1,'172.16.0.1');
Query OK, 1 row affected (0.00 sec)
Admin> SELECT hostgroup_id,hostname,weight,max_replication_lag FROM mysql_servers;
+--------------+------------+--------+---------------------+
| hostgroup_id | hostname | weight | max_replication_lag |
+--------------+------------+--------+---------------------+
| 0 | 172.16.0.1 | 1 | 0 |
| 1 | 172.16.0.2 | 1 | 0 |
| 1 | 172.16.0.3 | 1000 | 30 |
| 1 | 172.16.0.1 | 1 | 0 |
+--------------+------------+--------+---------------------+
4 rows in set (0.00 sec)
Admin> UPDATE mysql_servers SET max_replication_lag=30, weight=1000;
Query OK, 4 rows affected (0.00 sec)
Admin> UPDATE mysql_servers SET weight=1 WHERE hostname='172.16.0.1' AND hostgroup_id=1;
Query OK, 1 row affected (0.00 sec)
Admin> SELECT hostgroup_id,hostname,weight,max_replication_lag FROM mysql_servers;
+--------------+------------+--------+---------------------+
| hostgroup_id | hostname | weight | max_replication_lag |
+--------------+------------+--------+---------------------+
| 0 | 172.16.0.1 | 1000 | 30 |
| 1 | 172.16.0.2 | 1000 | 30 |
| 1 | 172.16.0.3 | 1000 | 30 |
| 1 | 172.16.0.1 | 1 | 30 |
+--------------+------------+--------+---------------------+
4 rows in set (0.00 sec)
上面的例子中,如果我们让hostgroup_id=1
的组负责read请求,那么99.95%的读请求都会均衡到 172.16.0.2 和 172.16.0.3 上,只有0.05%的读操作才会路由到 172.16.0.1 上。如果 172.16.0.2 和 172.16.0.3 都不可用了, 172.16.0.1 将负责所有的read请求。
注意:max_replication_lag
只对slave节点有效。如果某后端MySQL未启用复制功能,则Monitor模块不会做任何和复制相关的动作。
只需设置mysql_servers.compression
字段为一个非0值即可。注意,启用压缩功能(已load到runtime)后,只对从此之后建立的新连接才有效,已建立的连接(包括线程池中的空闲连接)不会对数据进行压缩传输。
Admin> SELECT hostgroup_id,hostname,compression FROM mysql_servers;
+--------------+------------+-------------+
| hostgroup_id | hostname | compression |
+--------------+------------+-------------+
| 0 | 172.16.0.1 | 0 |
| 1 | 172.16.0.2 | 0 |
| 1 | 172.16.0.3 | 0 |
| 1 | 172.16.0.1 | 0 |
+--------------+------------+-------------+
4 rows in set (0.00 sec)
Admin> UPDATE mysql_servers SET compression=1 WHERE hostname='172.16.0.2' AND hostgroup_id=1;
Query OK, 1 row affected (0.00 sec)
Admin> SELECT hostgroup_id,hostname,compression FROM mysql_servers;
+--------------+------------+-------------+
| hostgroup_id | hostname | compression |
+--------------+------------+-------------+
| 0 | 172.16.0.1 | 0 |
| 1 | 172.16.0.2 | 1 |
| 1 | 172.16.0.3 | 0 |
| 1 | 172.16.0.1 | 0 |
+--------------+------------+-------------+
4 rows in set (0.00 sec)
要graceful禁用一个后端节点,需要修改该后端节点的status
字段值为OFFLINE_SOFT
,这表示该节点正在处理的事务会继续执行,但ProxySQL不会向该节点发送新的请求。
Admin> SELECT hostgroup_id,hostname,status FROM mysql_servers;
+--------------+------------+--------+
| hostgroup_id | hostname | status |
+--------------+------------+--------+
| 0 | 172.16.0.1 | ONLINE |
| 1 | 172.16.0.2 | ONLINE |
| 1 | 172.16.0.3 | ONLINE |
| 1 | 172.16.0.1 | ONLINE |
+--------------+------------+--------+
4 rows in set (0.00 sec)
Admin> UPDATE mysql_servers SET status='OFFLINE_SOFT' WHERE hostname='172.16.0.2';
Query OK, 1 row affected (0.00 sec)
Admin> SELECT hostgroup_id,hostname,status FROM mysql_servers;
+--------------+------------+--------------+
| hostgroup_id | hostname | status |
+--------------+------------+--------------+
| 0 | 172.16.0.1 | ONLINE |
| 1 | 172.16.0.2 | OFFLINE_SOFT |
| 1 | 172.16.0.3 | ONLINE |
| 1 | 172.16.0.1 | ONLINE |
+--------------+------------+--------------+
4 rows in set (0.00 sec)
将status
字段的值设置为OFFLINE_HARD
,即表示强制禁用,可认为直接杀掉了该节点。该节点上正在执行的事务会停止,也不会向其发送任何请求。
Admin> SELECT hostgroup_id,hostname,status FROM mysql_servers;
+--------------+------------+--------------+
| hostgroup_id | hostname | status |
+--------------+------------+--------------+
| 0 | 172.16.0.1 | ONLINE |
| 1 | 172.16.0.2 | OFFLINE_SOFT |
| 1 | 172.16.0.3 | ONLINE |
| 1 | 172.16.0.1 | ONLINE |
+--------------+------------+--------------+
4 rows in set (0.00 sec)
Admin> UPDATE mysql_servers SET status='OFFLINE_HARD' WHERE hostname='172.16.0.1' AND hostgroup_id=1;
Query OK, 1 row affected (0.00 sec)
Admin> SELECT hostgroup_id,hostname,status FROM mysql_servers;
+--------------+------------+--------------+
| hostgroup_id | hostname | status |
+--------------+------------+--------------+
| 0 | 172.16.0.1 | ONLINE |
| 1 | 172.16.0.2 | OFFLINE_SOFT |
| 1 | 172.16.0.3 | ONLINE |
| 1 | 172.16.0.1 | OFFLINE_HARD |
+--------------+------------+--------------+
4 rows in set (0.00 sec)
直接将status
字段的值改回ONLINE
即可:
Admin> SELECT hostgroup_id,hostname,status FROM mysql_servers;
+--------------+------------+--------------+
| hostgroup_id | hostname | status |
+--------------+------------+--------------+
| 0 | 172.16.0.1 | ONLINE |
| 1 | 172.16.0.2 | OFFLINE_SOFT |
| 1 | 172.16.0.3 | ONLINE |
| 1 | 172.16.0.1 | OFFLINE_HARD |
+--------------+------------+--------------+
4 rows in set (0.00 sec)
Admin> UPDATE mysql_servers SET status='ONLINE' WHERE status NOT IN ('ONLINE');
Query OK, 2 rows affected (0.00 sec)
Admin> SELECT hostgroup_id,hostname,status FROM mysql_servers;
+--------------+------------+--------+
| hostgroup_id | hostname | status |
+--------------+------------+--------+
| 0 | 172.16.0.1 | ONLINE |
| 1 | 172.16.0.2 | ONLINE |
| 1 | 172.16.0.3 | ONLINE |
| 1 | 172.16.0.1 | ONLINE |
+--------------+------------+--------+
4 rows in set (0.00 sec)
删除mysql_servers
表中的行可以完全移除对应的后端节点:
Admin> SELECT hostgroup_id,hostname,status FROM mysql_servers;
+--------------+------------+--------+
| hostgroup_id | hostname | status |
+--------------+------------+--------+
| 0 | 172.16.0.1 | ONLINE |
| 1 | 172.16.0.2 | ONLINE |
| 1 | 172.16.0.3 | ONLINE |
| 1 | 172.16.0.1 | ONLINE |
+--------------+------------+--------+
4 rows in set (0.00 sec)
Admin> DELETE FROM mysql_servers WHERE hostgroup_id=1 AND hostname IN ('172.16.0.1','172.16.0.2');
Query OK, 2 rows affected (0.00 sec)
Admin> SELECT hostgroup_id,hostname,status FROM mysql_servers;
+--------------+------------+--------+
| hostgroup_id | hostname | status |
+--------------+------------+--------+
| 0 | 172.16.0.1 | ONLINE |
| 1 | 172.16.0.3 | ONLINE |
+--------------+------------+--------+
2 rows in set (0.00 sec)
在ProxySQL的内部,删除一个后端节点或将它设置为OFFLINE_HARD
的处理方式是一样的。当执行LOAD MYSQL SERVERS TO RUNTIME
后,主机组管理器(Hostgroup Manager)将探测到该节点已被移除,并在内部将器标记为OFFLINE_HARD
。
Translator:马龙帅
Blog:http://www.cnblogs.com/f-ck-need-u
- 须知:本译文适用于ProxySQL 1.4.4及之后版本
- 快速开始
- 配置使用ProxySQL
- 一步一步配置ProxySQL(HOWTO)
- ProxySQL读/写分离方法论(HOWTO)
- ProxySQL的线程
- Multiplexing
- 查询缓存
- Monitor模块
- ProxySQL集群
- 设计目标
- FAQ
- 以下是无关紧要或正处于测试中的内容,不翻译
- SSL configuration(不翻译)
- HTTP Web Server(不翻译)
- Clickhouse Support(不翻译)
- Mirroring(不翻译)
- 探测内存泄漏(不翻译)
- 错误代码(不翻译)
- 程序包制作(不翻译)