CentOS 7.5 部署 MySQL 5.7 基于GTID主从复制+并行复制+半同步复制+读写分离(ProxySQL) 环境- 运维笔记 (完整版)
之前已经详细介绍了Mysql基于GTID主从复制的概念,原理和配置,下面整体记录下MySQL5.7基于GTID主从复制+并行复制+增强半同步复制+读写分离环境的实现过程,以便加深对mysql新特性GTID复制的理解和实际业务场景中部署应用。
一、实验环境
[root@mysql-master ~]# cat /etc/redhat-release CentOS Linux release 7.5.1804 (Core) 为了方便实验,关闭所有节点的防火墙 [root@mysql-master ~]# systemctl stop firewalld [root@mysql-master ~]# firewall-cmd --state not running [root@mysql-master ~]# cat /etc/sysconfig/selinux |grep "SELINUX=disabled" SELINUX=disabled [root@mysql-master ~]# setenforce 0 setenforce: SELinux is disabled [root@mysql-master ~]# getenforce Disabled
二、安装Mysql5.7
在三个mysql节点机上使用yum方式安装Mysql5.7,参考:https://www.cnblogs.com/kevingrace/p/8340690.html 安装MySQL yum资源库 [root@mysql-master ~]# yum localinstall https://dev.mysql.com/get/mysql57-community-release-el7-8.noarch.rpm 安装MySQL 5.7 [root@mysql-master ~]# yum install -y mysql-community-server 启动MySQL服务器和MySQL的自动启动 [root@mysql-master ~]# systemctl start mysqld.service [root@mysql-master ~]# systemctl enable mysqld.service 设置登录密码 由于MySQL从5.7开始不允许首次安装后使用空密码进行登录!为了加强安全性,系统会随机生成一个密码以供管理员首次登录使用, 这个密码记录在/var/log/mysqld.log文件中,使用下面的命令可以查看此密码: [root@mysql-master ~]# cat /var/log/mysqld.log|grep 'A temporary password' 2019-01-11T05:53:17.824073Z 1 [Note] A temporary password is generated for root@localhost: TaN.k:*Qw2xs 使用上面查看的密码TaN.k:*Qw2xs 登录mysql,并重置密码为123456 [root@mysql-master ~]# mysql -p #输入默认的密码:TaN.k:*Qw2xs ............. mysql> set global validate_password_policy=0; Query OK, 0 rows affected (0.00 sec) mysql> set global validate_password_length=1; Query OK, 0 rows affected (0.00 sec) mysql> set password=password("123456"); Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> flush privileges; Query OK, 0 rows affected (0.00 sec) 查看mysql版本 [root@mysql-master ~]# mysql -p123456 ........ mysql> select version(); +-----------+ | version() | +-----------+ | 5.7.24 | +-----------+ 1 row in set (0.00 sec) ===================================================================== 温馨提示 mysql5.7通过上面默认安装后,执行语句可能会报错: ERROR 1819 (HY000): Your password does not satisfy the current policy requirements 这个报错与Mysql 密码安全策略validate_password_policy的值有关,validate_password_policy可以取0、1、2三个值: 解决办法: set global validate_password_policy=0; set global validate_password_length=1;
三、配置基于GTID的主从复制
传统的基于binlog position复制的方式有个严重的缺点:如果slave连接master时指定的binlog文件错误或者position错误,会造成遗漏或者重复,
很多时候前后数据是有依赖性的,这样就会出错而导致数据不一致。
从MYSQL5.6开始,mysql开始支持GTID复制。GTID的全称是global transaction id,表示的是全局事务ID。GTID的分配方式为uuid:trans_id,其中:uuid是每个mysql服务器都唯一的,记录在$datadir/auto.cnf中。如果复制结构中,任意两台服务器uuid重复的话(比如直接冷备份时,auto.conf中的内容是一致的),在启动复制功能的时候会报错。这时可以删除auto.conf文件再重启mysqld。
基于GTID主从复制的优点大致有:
- 保证同一个事务在某slave上绝对只执行一次,没有执行过的gtid事务总是会被执行。
- 不用像传统复制那样保证binlog的坐标准确,因为根本不需要binlog以及坐标。
- 故障转移到新的master的时候很方便,简化了很多任务。
- 很容易判断master和slave的数据是否一致。只要master上提交的事务在slave上也提交了,那么一定是一致的。
- 当然,MySQL提供了选项可以控制跳过某些gtid事务,防止slave第一次启动复制时执行master上的所有事务而导致耗时过久。
- 虽然对于row-based和statement-based的格式都能进行gtid复制,但建议采用row-based格式。
基于GTID主从复制环境部署记录
1)mysql-master主数据库上的操作 在my.cnf文件中配置GTID主从复制 [root@mysql-master ~]# cp /etc/my.cnf /etc/my.cnf.bak [root@mysql-master ~]# >/etc/my.cnf [root@mysql-master ~]# cat /etc/my.cnf [mysqld] datadir = /var/lib/mysql socket = /var/lib/mysql/mysql.sock symbolic-links = 0 log-error = /var/log/mysqld.log pid-file = /var/run/mysqld/mysqld.pid #GTID: server_id = 1 gtid_mode = on enforce_gtid_consistency = on #binlog log_bin = mysql-bin log-slave-updates = 1 binlog_format = row sync-master-info = 1 sync_binlog = 1 #relay log skip_slave_start = 1 配置后,记得重启mysql服务 [root@mysql-master ~]# systemctl restart mysqld 登录mysql,并查看master状态, 发现多了一项"Executed_Gtid_Set " mysql> show master status; +-------------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +-------------------+----------+--------------+------------------+-------------------+ | mysql-bin.000001 | 154 | | | | +-------------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec) mysql> show global variables like '%uuid%'; +---------------+--------------------------------------+ | Variable_name | Value | +---------------+--------------------------------------+ | server_uuid | 317e2aad-1565-11e9-9c2e-005056ac6820 | +---------------+--------------------------------------+ 1 row in set (0.00 sec) 查看确认gtid功能打开 mysql> show global variables like '%gtid%'; +----------------------------------+-------+ | Variable_name | Value | +----------------------------------+-------+ | binlog_gtid_simple_recovery | ON | | enforce_gtid_consistency | ON | | gtid_executed | | | gtid_executed_compression_period | 1000 | | gtid_mode | ON | | gtid_owned | | | gtid_purged | | | session_track_gtids | OFF | +----------------------------------+-------+ 8 rows in set (0.00 sec) 查看确认binlog日志功能打开 mysql> show variables like 'log_bin'; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | log_bin | ON | +---------------+-------+ 1 row in set (0.00 sec) 授权slave复制用户,并刷新权限 mysql> grant replication slave,replication client on *.* to slave@'172.16.60.212' identified by "slave@123"; Query OK, 0 rows affected, 1 warning (0.03 sec) mysql> flush privileges; Query OK, 0 rows affected (0.04 sec) mysql> show grants for slave@'172.16.60.212'; +-------------------------------------------------------------------------------+ | Grants for slave@172.16.60.212 | +-------------------------------------------------------------------------------+ | GRANT REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'slave'@'172.16.60.212' | +-------------------------------------------------------------------------------+ 1 row in set (0.00 sec) 再次查看master状态 mysql> show master status; +-------------------+----------+--------------+------------------+------------------------------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +-------------------+----------+--------------+------------------+------------------------------------------+ | mysql-bin.000001 | 622 | | | 317e2aad-1565-11e9-9c2e-005056ac6820:1-2 | +-------------------+----------+--------------+------------------+------------------------------------------+ 1 row in set (0.00 sec) 这里需要注意一下: 启动配置之前,同样需要对从服务器进行初始化。对从服务器初始化的方法基本和基于日志点是相同的,只不过在启动了GTID模式后, 在备份中所记录的就不是备份时的二进制日志文件名和偏移量了,而是记录的是备份时最后的GTID值。 需要先在主数据库机器上把目标库备份一下,假设这里目标库是kevin(为了测试效果,下面手动创建) mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | +--------------------+ 4 rows in set (0.00 sec) mysql> CREATE DATABASE kevin CHARACTER SET utf8 COLLATE utf8_general_ci; Query OK, 1 row affected (0.02 sec) mysql> use kevin; Database changed mysql> create table if not exists haha (id int(10) PRIMARY KEY AUTO_INCREMENT,name varchar(50) NOT NULL); Query OK, 0 rows affected (0.27 sec) mysql> insert into kevin.haha values(1,"congcong"),(2,"huihui"),(3,"grace"); Query OK, 3 rows affected (0.06 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> select * from kevin.haha; +----+----------+ | id | name | +----+----------+ | 1 | congcong | | 2 | huihui | | 3 | grace | +----+----------+ 3 rows in set (0.00 sec) 把kevin库备份出来 [root@mysql-master ~]# mysqldump --single-transaction --master-data=2 --triggers --routines --databases kevin -uroot -p123456 > /root/kevin.sql 这里稍微注意下: mysql5.6使用mysqldump备份时,指定备份的具体库,使用--database mysql5.7使用mysqldump备份时,指定备份的具体库,使用--databases [root@mysql-master ~]# ls /root/kevin.sql /root/kevin.sql [root@mysql-master ~]# cat /root/kevin.sql -- MySQL dump 10.13 Distrib 5.7.24, for Linux (x86_64) -- -- Host: localhost Database: kevin -- ------------------------------------------------------ -- Server version 5.7.24-log ............. ............. -- -- GTID state at the beginning of the backup -- SET @@GLOBAL.GTID_PURGED='317e2aad-1565-11e9-9c2e-005056ac6820:1-5'; 然后把备份的/root/kevin.sql文件拷贝到mysql-slave1从数据库服务器上 [root@mysql-master ~]# rsync -e "ssh -p22" -avpgolr /root/kevin.sql root@172.16.60.212:/root/ ============================================================== 2)mysql-slave1从数据库上的操作 在my.cnf文件中配置GTID主从复制 与主服务器配置大概一致,除了server_id不一致外,从服务器还可以在配置文件里面添加:"read_only=on" , 使从服务器只能进行读取操作,此参数对超级用户无效,并且不会影响从服务器的复制; [root@mysql-slave1 ~]# cp /etc/my.cnf /etc/my.cnf.bak [root@mysql-slave1 ~]# >/etc/my.cnf [root@mysql-slave1 ~]# vim /etc/my.cnf [mysqld] datadir = /var/lib/mysql socket = /var/lib/mysql/mysql.sock symbolic-links = 0 log-error = /var/log/mysqld.log pid-file = /var/run/mysqld/mysqld.pid #GTID: server_id = 2 gtid_mode = on enforce_gtid_consistency = on #binlog log_bin = mysql-bin log-slave-updates = 1 binlog_format = row sync-master-info = 1 sync_binlog = 1 #relay log skip_slave_start = 1 read_only = on 配置完成后,记得重启mysql服务 [root@mysql-slave1 ~]# systemctl restart mysqld 接着将主数据库目标库的备份数据kevin.sql导入到从数据库里 [root@mysql-slave1 ~]# ls /root/kevin.sql /root/kevin.sql [root@mysql-slave1 ~]# mysql -p123456 ......... mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | +--------------------+ 4 rows in set (0.00 sec) mysql> source /root/kevin.sql; mysql> select * from kevin.haha; +----+----------+ | id | name | +----+----------+ | 1 | congcong | | 2 | huihui | | 3 | grace | +----+----------+ 3 rows in set (0.00 sec) 在从数据库里,使用change master 配置主从复制 mysql> stop slave; Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> change master to master_host='172.16.60.211',master_user='slave',master_password='slave@123',master_auto_position=1; Query OK, 0 rows affected, 2 warnings (0.26 sec) mysql> start slave; Query OK, 0 rows affected (0.02 sec) mysql> show slave status \G; *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 172.16.60.211 Master_User: slave Master_Port: 3306 Connect_Retry: 60 Master_Log_File: mysql-bin.000001 Read_Master_Log_Pos: 1357 Relay_Log_File: mysql-slave1-relay-bin.000002 Relay_Log_Pos: 417 Relay_Master_Log_File: mysql-bin.000001 Slave_IO_Running: Yes Slave_SQL_Running: Yes ................ ................ Executed_Gtid_Set: 317e2aad-1565-11e9-9c2e-005056ac6820:1-5 Auto_Position: 1 由上面可知,mysql-slave1节点已经和mysql-master节点配置了主从同步关系 3) mysql-master主数据库上进行状态查看和测试测试插入 mysql> show master status; +-------------------+----------+--------------+------------------+------------------------------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +-------------------+----------+--------------+------------------+------------------------------------------+ | mysql-bin.000001 | 1357 | | | 317e2aad-1565-11e9-9c2e-005056ac6820:1-5 | +-------------------+----------+--------------+------------------+------------------------------------------+ 1 row in set (0.00 sec) mysql> show slave hosts; +-----------+------+------+-----------+--------------------------------------+ | Server_id | Host | Port | Master_id | Slave_UUID | +-----------+------+------+-----------+--------------------------------------+ | 2 | | 3306 | 1 | 2c1efc46-1565-11e9-ab8e-00505688047c | +-----------+------+------+-----------+--------------------------------------+ 1 row in set (0.00 sec) mysql> insert into kevin.haha values(4,"beijing"),(5,"hefei"),(10,"xihu"); Query OK, 3 rows affected (0.06 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> delete from kevin.haha where id<4; Query OK, 3 rows affected (0.10 sec) mysql> select * from kevin.haha; +----+---------+ | id | name | +----+---------+ | 4 | beijing | | 5 | hefei | | 10 | xihu | +----+---------+ 3 rows in set (0.00 sec) 4)mysql-slave1从数据库上查看 mysql> select * from kevin.haha; +----+---------+ | id | name | +----+---------+ | 4 | beijing | | 5 | hefei | | 10 | xihu | +----+---------+ 3 rows in set (0.00 sec) 发现mysql-slave1从数据库已经将新插入的数据同步过来了,由此,基于GTID的主从同步复制关系已经正常部署完成了!
四、并行复制 (解决主从复制延迟问题)
一般Mysql主从复制有三个线程参与,都是单线程:Binlog Dump(主) -> IO Thread (从) -> SQL Thread(从)。复制出现延迟一般出在两个地方:
- SQL线程忙不过来 (可能需要应用数据量较大,可能和从库本身的一些操作有锁和资源的冲突;主库可以并发写,SQL线程不可以;主要原因)
- 网络抖动导致IO线程复制延迟(次要原因)。
MySQL主从复制延迟的解决办法:MySQL从5.6开始有了SQL Thread多个的概念,可以并发还原数据,即并行复制技术。并行复制的机制,是MySQL的一个非常重要的特性,可以很好的解决MySQL主从延迟问题!
在MySQL 5.6中,设置参数slave_parallel_workers = 4(>1),即可有4个SQL Thread(coordinator线程)来进行并行复制,其状态为:Waiting for an evant from Coordinator。但是其并行只是基于Schema的,也就是基于库的。如果数据库实例中存在多个Schema,这样设置对于Slave复制的速度可以有比较大的提升。通常情况下单库多表是更常见的一种情形,那基于库的并发就没有卵用。其核心思想是:不同schema下的表并发提交时的数据不会相互影响,即slave节点可以用对relay log中不同的schema各分配一个类似SQL功能的线程,来重放relay log中主库已经提交的事务,保持数据与主库一致。
MySQL 5.6版本支持所谓的并行复制,但是其并行只是基于schema的,也就是基于库的。如果用户的MySQL数据库实例中存在多个schema,对于从机复制的速度的确可以有比较大的帮助。但是基于schema的并行复制存在两个问题:
1) crash safe功能不好做,因为可能之后执行的事务由于并行复制的关系先完成执行,那么当发生crash的时候,这部分的处理逻辑是比较复杂的。
2) 最为关键的问题是这样设计的并行复制效果并不高,如果用户实例仅有一个库,那么就无法实现并行回放,甚至性能会比原来的单线程更差。而 单库多表是比多库多表更为常见的一种情形 。
注意:mysql 5.6的MTS是基于库级别的并行,当有多个数据库时,可以将slave_parallel_workers设置为数据库的数量,为了避免新建库后来回修改,也可以将该参数设置的大一些。设置为库级别的事务时,不允许这样做,会报错。
在MySQL 5.7中,引入了基于组提交的并行复制(官方称为Enhanced Multi-threaded Slaves,即MTS),设置参数slave_parallel_workers>0并且global.slave_parallel_type=‘LOGICAL_CLOCK’,即可支持一个schema下,slave_parallel_workers个的worker线程并发执行relay log中主库提交的事务。其核心思想:一个组提交的事务都是可以并行回放(配合binary log group commit);slave机器的relay log中 last_committed相同的事务(sequence_num不同)可以并发执行。其中,变量slave-parallel-type可以有两个值:1)DATABASE 默认值,基于库的并行复制方式;2)LOGICAL_CLOCK,基于组提交的并行复制方式;
MySQL 5.7开启Enhanced Multi-Threaded Slave很简单,只需要在Slave从数据库的my.cnf文件中如下配置即可:
# slave slave-parallel-type=LOGICAL_CLOCK slave-parallel-workers=8 #一般建议设置4-8,太多的线程会增加线程之间的同步开销 master_info_repository=TABLE relay_log_info_repository=TABLE relay_log_recovery=ON
MySQL 5.7是基于组提交的并行复制,并且是支持"真正"的并行复制功能,这其中最为主要的原因:就是slave服务器的回放与主机是一致的, 即master服务器上是怎么并行执行的slave上就怎样进行并行回放。不再有库的并行复制限制,对于二进制日志格式也无特殊的要求(基于库的并行复制也没有要求)。
MySQL5.7的并行复制,期望最大化还原主库的并行度,实现方式是在binlog event中增加必要的信息,以便slave节点根据这些信息实现并行复制。MySQL5.7的并行复制建立在group commit的基础上,所有在主库上能够完成prepared的语句表示没有数据冲突,就可以在slave节点并行复制。
所以在并行复制环境中,除了在Slace从数据库中配置之外,还需要在Master主数据库上的my.cnf文件中添加binlog_group_commit配置,否则从库无法做到基于事物的并行复制:
binlog_group_commit_sync_delay = 100 binlog_group_commit_sync_no_delay_count = 10
binlog_group_commit_sync_delay,这个参数控制着日志在刷盘前日志提交要等待的时间,默认是0也就是说提交后立即刷盘,但是并不代表是关闭了组提交,当设置为0以上的时候,就允许多个事物的日志同时间一起提交刷盘,也就是我们说的组提交。组提交是并行复制的基础,我们设置这个值的大于0就代表打开了组提交的延迟功能,而组提交是默认开启的。最大值只能设置为1000000微妙。
binlog_group_commit_sync_no_delay_count ,这个参数表示我们在binlog_group_commit_sync_delay等待时间内,如果事物数达到这个参数的设定值,就会触动一次组提交,如果这个值设为0的话就不会有任何的影响。如果到达时间但是事物数并没有达到的话,也是会进行一次组提交操作的。
MySQL 5.7并行复制的思想简单易懂,一言以蔽之: 一个组提交的事务都是可以并行回放 ,因为这些事务都已进入到事务的prepare阶段,则说明事务之间没有任何冲突(否则就不可能提交)。为了兼容MySQL 5.6基于库的并行复制,5.7引入了新的变量slave-parallel-type,其可以配置的值有:
- DATABASE:默认值,基于库的并行复制方式
- LOGICAL_CLOCK:基于组提交的并行复制方式
支持并行复制的GTID
如何知道事务是否在一组中,又是一个问题,因为原版的MySQL并没有提供这样的信息。在MySQL 5.7版本中,其设计方式是将组提交的信息存放在GTID中。那么如果用户没有开启GTID功能,即将参数gtid_mode设置为OFF呢?故MySQL 5.7又引入了称之为Anonymous_Gtid的二进制日志event类型,如:
mysql> SHOW BINLOG EVENTS in 'mysql-bin.000003'; +------------------+-----+----------------+-----------+-------------+-----------------------------------------------+ | Log_name | Pos | Event_type | Server_id | End_log_pos | Info | +------------------+-----+----------------+-----------+-------------+-----------------------------------------------+ | mysql-bin.000003 | 4 | Format_desc | 88 | 123 | Server ver: 5.7.7-rc-debug-log, Binlog ver: 4 | | mysql-bin.000003 | 123 | Previous_gtids | 88 | 194 | f11232f7-ff07-11e4-8fbb-00ff55e152c6:1-2 | | mysql-bin.000003 | 194 | Anonymous_Gtid | 88 | 259 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' | | mysql-bin.000003 | 259 | Query | 88 | 330 | BEGIN | | mysql-bin.000003 | 330 | Table_map | 88 | 373 | table_id: 108 (aaa.t) | | mysql-bin.000003 | 373 | Write_rows | 88 | 413 | table_id: 108 flags: STMT_END_F | ......
这意味着在 MySQL 5.7版本中即使不开启GTID,每个事务开始前也是会存在一个Anonymous_Gtid ,而这GTID中就存在着组提交的信息。
LOGICAL_CLOCK
然而,通过上述的SHOW BINLOG EVENTS,并没有发现有关组提交的任何信息。但是通过mysqlbinlog工具,用户就能发现组提交的内部信息:
如下查看一个binlog日志
root@localhost:~# mysqlbinlog mysql-bin.0000002 | grep last_committed #190112 17:45:16 server id 1 end_log_pos 219 CRC32 0xca2ee8c2 GTID last_committed=0 sequence_number=1 rbr_only=yes #190112 17:45:21 server id 1 end_log_pos 506 CRC32 0xe8047dd2 GTID last_committed=1 sequence_number=2 rbr_only=yes #190112 17:45:16 server id 1 end_log_pos 219 CRC32 0xca2ee8c2 GTID last_committed=2 sequence_number=3 rbr_only=yes #190112 17:45:21 server id 1 end_log_pos 506 CRC32 0xe8047dd2 GTID last_committed=3 sequence_number=4 rbr_only=yes
root@localhost:~# mysqlbinlog mysql-bin.0000006 | grep last_committed #150520 14:23:11 server id 88 end_log_pos 259 CRC32 0x4ead9ad6 GTID last_committed=0 sequence_number=1 #150520 14:23:11 server id 88 end_log_pos 1483 CRC32 0xdf94bc85 GTID last_committed=0 sequence_number=2 #150520 14:23:11 server id 88 end_log_pos 2708 CRC32 0x0914697b GTID last_committed=0 sequence_number=3 #150520 14:23:11 server id 88 end_log_pos 3934 CRC32 0xd9cb4a43 GTID last_committed=0 sequence_number=4 #150520 14:23:11 server id 88 end_log_pos 5159 CRC32 0x06a6f531 GTID last_committed=0 sequence_number=5 #150520 14:23:11 server id 88 end_log_pos 6386 CRC32 0xd6cae930 GTID last_committed=0 sequence_number=6 #150520 14:23:11 server id 88 end_log_pos 7610 CRC32 0xa1ea531c GTID last_committed=6 sequence_number=7 #150520 14:23:11 server id 88 end_log_pos 8834 CRC32 0x96864e6b GTID last_committed=6 sequence_number=8 #150520 14:23:11 server id 88 end_log_pos 10057 CRC32 0x2de1ae55 GTID last_committed=6 sequence_number=9 #150520 14:23:11 server id 88 end_log_pos 11280 CRC32 0x5eb13091 GTID last_committed=6 sequence_number=10 #150520 14:23:11 server id 88 end_log_pos 12504 CRC32 0x16721011 GTID last_committed=6 sequence_number=11 #150520 14:23:11 server id 88 end_log_pos 13727 CRC32 0xe2210ab6 GTID last_committed=6 sequence_number=12 #150520 14:23:11 server id 88 end_log_pos 14952 CRC32 0xf41181d3 GTID last_committed=12 sequence_number=13 ...
例如上述last_committed为0的事务有6个,这意味什么呢?意味着这6个事物是作为一个组提交的,6个事物在perpare截断获取相同的last_committed而且相互不影响,最终是会作为一个组进行提交?,这就是所谓的组提交!上面表示组提交时提交了6个事务,而这6个事务在从机是可以进行并行回放的。
总之:MySQL 5.7推出的Enhanced Multi-Threaded Slave解决了困扰MySQL长达数十年的复制延迟问题,再次提醒一些无知的PostgreSQL用户,不要再停留在之前对于MySQL的印象,物理复制也不一定肯定比逻辑复制有优势,而MySQL 5.7的MTS已经完全可以解决延迟问题。总之, 5.7版本后,主从复制延迟问题将不存在!
基于GTID的并行复制环境部署记录
1)在mysql-slave1从数据库的my.cnf 文件中添加下面MTS并行复制的配置 [root@mysql-slave1 ~]# vim /etc/my.cnf [mysqld] datadir = /var/lib/mysql socket = /var/lib/mysql/mysql.sock symbolic-links = 0 log-error = /var/log/mysqld.log pid-file = /var/run/mysqld/mysqld.pid #GTID: server_id = 2 gtid_mode = on enforce_gtid_consistency = on #binlog log_bin = mysql-bin log-slave-updates = 1 binlog_format = row sync-master-info = 1 sync_binlog = 1 #relay log skip_slave_start = 1 read_only = on #MTS slave-parallel-type = LOGICAL_CLOCK #开启逻辑时钟的复制 slave-parallel-workers = 4 #这里设置线程数为4 (最大线程数不能超过16,即最大线程为16) master_info_repository = TABLE relay_log_info_repository = TABLE relay_log_recovery = on 配置完成后,记得重启mysql服务 [root@mysql-slave1 ~]# systemctl restart mysqld 2)在mysql-master主数据库的my.cnf 文件中添加最后两行配置 [root@mysql-master ~]# vim /etc/my.cnf [mysqld] datadir = /var/lib/mysql socket = /var/lib/mysql/mysql.sock symbolic-links = 0 log-error = /var/log/mysqld.log pid-file = /var/run/mysqld/mysqld.pid #GTID: server_id = 1 gtid_mode = on enforce_gtid_consistency = on #binlog log_bin = mysql-bin log-slave-updates = 1 binlog_format = row sync-master-info = 1 sync_binlog = 1 #relay log skip_slave_start = 1 #不配置binlog_group_commit从库无法做到基于事物的并行复制 binlog_group_commit_sync_delay = 100 binlog_group_commit_sync_no_delay_count = 10 #为了数据安全再配置 sync_binlog=1 innodb_flush_log_at_trx_commit =1 #这个参数控制binlog写入 磁盘的方式。设置为1时,表示每次commit;都写入磁盘。这个刷新的是redo log 即ib_logfile0,而不是binlog 配置完成后,记得重启mysql服务 [root@mysql-master ~]# systemctl restart mysqld 登录mysql,查看binlog_group_commit mysql> show variables like 'binlog_group_commit_%'; +-----------------------------------------+-------+ | Variable_name | Value | +-----------------------------------------+-------+ | binlog_group_commit_sync_delay | 100 | | binlog_group_commit_sync_no_delay_count | 10 | +-----------------------------------------+-------+ 2 rows in set (0.00 sec) 设置binlog_group_commit的上面两个参数,否则从库无法做到基于事物的并行复制! 这两个参数共同决定了是否触发组提交操作! 第二个参数表示该事务组提交之前总共等待累积到多少个事务(如上要累计到10个事务); 第一个参数则表示该事务组总共等待多长时间后进行提交(如上要总共等待100毫秒的时间),任何一个条件满足则进行后续操作。 因为有这个等待,可以让更多事务的binlog通过一次写binlog文件磁盘来完成提交,从而获得更高的吞吐量。 3)登录mysql-slave1从数据库 上面在配置并行复制后,主从数据库的mysqld服务都重启了,此时需要重启从数据库上的slave,这样才能恢复正常的主从同步状态! 记住:只要主数据库的mysqld服务重启,那么从数据库上就要重启slave,以恢复主从同步状态!!! mysql> show slave status \G; ........... ........... Slave_IO_Running: No Slave_SQL_Running: No mysql> stop slave; Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> start slave; Query OK, 0 rows affected (0.10 sec) mysql> show slave status \G; .......... .......... Slave_IO_Running: Yes Slave_SQL_Running: Yes .......... Executed_Gtid_Set: 317e2aad-1565-11e9-9c2e-005056ac6820:1-11 Auto_Position: 1 这样,mysql-slave1从数据库就恢复了与mysql-master主数据库的同步关系了 查看优化项 mysql> use mysql; #切入到mysql库 Database changed mysql> select * from slave_worker_info; #查看slave_worker_info表 +----+---------------------------------+---------------+-------------------+----------------+---------------------------------+--------------------------+----------------------------+---------------------------+------------------+-----------------------+------------------------------------------------------------------+--------------+ | Id | Relay_log_name | Relay_log_pos | Master_log_name | Master_log_pos | Checkpoint_relay_log_name | Checkpoint_relay_log_pos | Checkpoint_master_log_name | Checkpoint_master_log_pos | Checkpoint_seqno | Checkpoint_group_size | Checkpoint_group_bitmap | Channel_name | +----+---------------------------------+---------------+-------------------+----------------+---------------------------------+--------------------------+----------------------------+---------------------------+------------------+-----------------------+------------------------------------------------------------------+--------------+ | 1 | ./mysql-slave1-relay-bin.000005 | 656 | mysql-bin.000008 | 481 | ./mysql-slave1-relay-bin.000005 | 369 | mysql-bin.000008 | 194 | 0 | 64 | | | | 2 | | 0 | | 0 | | 0 | | 0 | 0 | 64 | | | | 3 | | 0 | | 0 | | 0 | | 0 | 0 | 64 | | | | 4 | | 0 | | 0 | | 0 | | 0 | 0 | 64 | | | +----+---------------------------------+---------------+-------------------+----------------+---------------------------------+--------------------------+----------------------------+---------------------------+------------------+-----------------------+------------------------------------------------------------------+--------------+ 4 rows in set (0.00 sec) 以上可以查看到,mysql库下的slave_worker_info表下查看到4个线程 也可以使用下面命令查看线程数,这个跟在my.cnf文件里配置的是一样的! mysql> show variables like '%slave_para%'; +------------------------+---------------+ | Variable_name | Value | +------------------------+---------------+ | slave_parallel_type | LOGICAL_CLOCK | | slave_parallel_workers | 4 | +------------------------+---------------+ 2 rows in set (0.00 sec) 4)同步复制测试 在mysql-master主数据库插入新数据 mysql> insert into kevin.haha values(21,"caiyi"),(22,"manman"),(23,"titi"); Query OK, 3 rows affected (0.09 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> select * from kevin.haha; +----+---------+ | id | name | +----+---------+ | 4 | beijing | | 5 | hefei | | 10 | xihu | | 21 | caiyi | | 22 | manman | | 23 | titi | +----+---------+ 6 rows in set (0.00 sec) 然后在mysql-slave1从数据库查看,发现新数据已经同步过来了 mysql> select * from kevin.haha; +----+---------+ | id | name | +----+---------+ | 4 | beijing | | 5 | hefei | | 10 | xihu | | 21 | caiyi | | 22 | manman | | 23 | titi | +----+---------+ 6 rows in set (0.00 sec) 最后在mysql-master主数据库上查看组提交信息 [root@mysql-master ~]# cd /var/lib/mysql [root@mysql-master mysql]# ll mysql-bin* -rw-r----- 1 mysql mysql 751 Jan 12 18:08 mysql-bin.000001 -rw-r----- 1 mysql mysql 1365 Jan 12 19:28 mysql-bin.000002 -rw-r----- 1 mysql mysql 1326 Jan 12 19:42 mysql-bin.000003 -rw-r----- 1 mysql mysql 57 Jan 12 19:28 mysql-bin.index [root@mysql-master mysql]# mysqlbinlog mysql-bin.000003 |grep last_committed #190112 19:37:06 server id 1 end_log_pos 259 CRC32 0x893c0ae8 GTID last_committed=0 sequence_number=1 rbr_only=yes #190112 19:37:12 server id 1 end_log_pos 542 CRC32 0xc36def61 GTID last_committed=1 sequence_number=2 rbr_only=yes #190112 19:42:42 server id 1 end_log_pos 825 CRC32 0x361701a2 GTID last_committed=2 sequence_number=3 rbr_only=yes #190112 19:42:48 server id 1 end_log_pos 1108 CRC32 0x8ba858c7 GTID last_committed=3 sequence_number=4 rbr_only=yes 如上,通过最新的binlog日志看到,last_committed数值都不一样,即没有事务是在同一个组内提交的,也就是说这个日志里没有组提交信息。 这是因为没有满足binlog_grup_commit那两个参数的条件,所以没有进行组提交!
五、半同步复制
半同步复制: 默认情况下MySQL的复制是异步的,master将新生成的binlog发送给各slave后,无需等待slave的ack回复(slave将接收到的binlog写进relay log后才会回复ack),直接就认为这次DDL/DML成功了, 半同步复制(semi-synchronous replication)是指master将新生成的binlog发送给各slave时, 只需等待一个(默认)slave返回的ack信息就返回成功。
MySQL 5.7对半同步复制作了大改进,新增了一个master线程。在MySQL 5.7以前,master上的binlog dump线程负责两件事:dump日志给slave的io_thread;接收来自slave的ack消息。它们是串行方式工作的。在MySQL 5.7中,新增了一个专门负责接受ack消息的线程ack collector thread。这样master上有两个线程独立工作,可以同时发送binlog到slave和接收slave的ack。还新增了几个变量,其中最重要的是 rpl_semi_sync_master_wait_point ,它使得MySQL半同步复制有两种工作模型。
半同步复制的两种类型
从MySQL 5.7.2开始,MySQL支持两种类型的半同步复制。这两种类型由变量 rpl_semi_sync_master_wait_point (MySQL 5.7.2之前没有该变量)控制,它有两种值:AFTER_SYNC和AFTER_COMMIT。在MySQL 5.7.2之后,默认值为AFTER_SYNC,在此版本之前,等价的类型为AFTER_COMMIT。这个变量控制的是master何时提交、何时接收ack以及何时回复成功信息给客户端的时间点。
AFTER_SYNC模式:master将新事务写进binlog(buffer)后发送给slave,再sync到自己的binlog file(disk), 之后才允许接收slave的ack回复,接收到ack之后才会提交事务,并返回成功信息给客户端。
AFTER_COMMIT模式:master将新事务写进binlog(buffer)后发送给slave,再sync到自己的binlog file(disk),然后直接提交事务。之后才允许接收slave的ack回复,然后再返回成功信息给客户端。
如下作图,理解起来就容易了。(前提: 已经设置了sync_binlog=1,否则binlog刷盘时间由操作系统决定)
根据上面的图解,接下来分析下这两种模式的优缺点。
AFTER_SYNC
- 对于所有客户端来说,它们看到的数据是一样的,因为它们看到的数据都是在接收到slave的ack后提交后的数据。
- 这种模式下,如果master突然故障,不会丢失数据,因为所有成功的事务都已经写进slave的relay log中了,slave的数据是最新的。
AFTER_COMMIT
- 不同客户端看到的数据可能是不一样的。对于发起事务请求的那个客户端,它只有在master提交事务且收到slave的ack后才能看到提交的数据。但对于那些非本次事务的请求客户端,它们在master提交后就能看到提交后的数据,这时候master可能还没收到slave的ack。
- 如果master收到ack回复前,slave和master都故障了,那么将丢失这个事务中的数据。
在MySQL 5.7.2之前,等价的模式是 AFTER_COMMIT ,在此版本之后,默认的模式为 AFTER_SYNC ,该模式能最大程度地保证数据安全性,且性能上并不比 AFTER_COMMIT 差。
基于GTID的半同步复制环境部署记录
Mysql 半同步复制配置可以参考: https://www.cnblogs.com/kevingrace/p/10228694.html 开启半同步复制的方法有两种: mysql命令行启动; my.cnf文件里添加启动配置; 推荐在my.cnf文件里添加半同步启动配置方式 1) 配置mysql-master主数据库上 my.cnf文件,添加启动半同步复制的配置 [root@mysql-master ~]# vim /etc/my.cnf [mysqld] datadir = /var/lib/mysql socket = /var/lib/mysql/mysql.sock symbolic-links = 0 log-error = /var/log/mysqld.log pid-file = /var/run/mysqld/mysqld.pid #GTID: server_id = 1 gtid_mode = on enforce_gtid_consistency = on #binlog log_bin = mysql-bin log-slave-updates = 1 binlog_format = row sync-master-info = 1 sync_binlog = 1 #relay log skip_slave_start = 1 #不配置binlog_group_commit从库无法做到基于事物的并行复制 binlog_group_commit_sync_delay = 100 binlog_group_commit_sync_no_delay_count = 10 #为了数据安全再配置 sync_binlog=1 innodb_flush_log_at_trx_commit =1 #这个参数控制binlog写入 磁盘的方式。设置为1时,表示每次commit;都写入磁盘。这个刷新的是redo log 即ib_logfile0,而不是binlog #开启半同步复制 (超时时间为1s) plugin-load=rpl_semi_sync_master=semisync_master.so rpl_semi_sync_master_enabled = 1 rpl_semi_sync_master_timeout = 1000 配置完成后,记得重启mysql服务 [root@mysql-master ~]# systemctl restart mysqld 2) 配置mysql-slave从数据库上 my.cnf文件,添加启动半同步复制的配置 [root@mysql-slave1 ~]# vim /etc/my.cnf [mysqld] datadir = /var/lib/mysql socket = /var/lib/mysql/mysql.sock symbolic-links = 0 log-error = /var/log/mysqld.log pid-file = /var/run/mysqld/mysqld.pid #GTID: server_id = 2 gtid_mode = on enforce_gtid_consistency = on #binlog log_bin = mysql-bin log-slave-updates = 1 binlog_format = row sync-master-info = 1 sync_binlog = 1 #relay log skip_slave_start = 1 read_only = on #MTS slave-parallel-type = LOGICAL_CLOCK #开启逻辑时钟的复制 slave-parallel-workers = 4 #最大线程16 master_info_repository = TABLE relay_log_info_repository = TABLE relay_log_recovery = on # 开启半同步复制 plugin-load=rpl_semi_sync_slave=semisync_slave.so rpl_semi_sync_slave_enabled=1 配置完成后,记得重启mysql服务 [root@mysql-slave1 ~]# systemctl restart mysqld 3)在mysql-master主数据库上加载 (前提是/usr/lib64/mysql/plugin/semisync_master.so 文件存在。 一般mysql安装后就默认产生) mysql> INSTALL PLUGIN rpl_semi_sync_master SONAME 'semisync_master.so'; Query OK, 0 rows affected (0.25 sec) 查看插件是否加载成功 mysql> SELECT PLUGIN_NAME, PLUGIN_STATUS FROM INFORMATION_SCHEMA.PLUGINS WHERE PLUGIN_NAME LIKE '%semi%'; +----------------------+---------------+ | PLUGIN_NAME | PLUGIN_STATUS | +----------------------+---------------+ | rpl_semi_sync_master | ACTIVE | +----------------------+---------------+ 1 row in set (0.00 sec) 查看半同步是否在运行 mysql> show status like 'Rpl_semi_sync_master_status'; +-----------------------------+-------+ | Variable_name | Value | +-----------------------------+-------+ | Rpl_semi_sync_master_status | ON | +-----------------------------+-------+ 1 row in set (0.00 sec) 4)在mysql-slave1从数据库上加载 (前提是/usr/lib64/mysql/plugin/semisync_slave.so 文件存在。 一般mysql安装后就默认产生) mysql> INSTALL PLUGIN rpl_semi_sync_slave SONAME 'semisync_slave.so'; Query OK, 0 rows affected (0.03 sec) 查看插件是否加载成功 mysql> SELECT PLUGIN_NAME, PLUGIN_STATUS FROM INFORMATION_SCHEMA.PLUGINS WHERE PLUGIN_NAME LIKE '%semi%'; +---------------------+---------------+ | PLUGIN_NAME | PLUGIN_STATUS | +---------------------+---------------+ | rpl_semi_sync_slave | ACTIVE | +---------------------+---------------+ 1 row in set (0.00 sec) 这个时候,查看mysql-slave1的半同步是否运行 mysql> show status like 'Rpl_semi_sync_slave_status'; +----------------------------+-------+ | Variable_name | Value | +----------------------------+-------+ | Rpl_semi_sync_slave_status | OFF | +----------------------------+-------+ 1 row in set (0.01 sec) 发现还是OFF,明明已经在my.cnf文件里开启了! 这是因为此时还没有生效,必须从数据库上的IO线程才能生产!!! mysql> STOP SLAVE IO_THREAD; Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> START SLAVE IO_THREAD; Query OK, 0 rows affected (0.00 sec) 然后再查看mysql-slave1的半同步状态,发现就已经开启了! mysql> show status like 'Rpl_semi_sync_slave_status'; +----------------------------+-------+ | Variable_name | Value | +----------------------------+-------+ | Rpl_semi_sync_slave_status | ON | +----------------------------+-------+ 1 row in set (0.00 sec) 查看此时的主从同步状态 mysql> show slave status \G; ........... ........... Slave_IO_Running: Yes Slave_SQL_Running: No 发现主从同步异常,这个时候再重启下slave即可! mysql> stop slave; Query OK, 0 rows affected (0.06 sec) mysql> start slave; Query OK, 0 rows affected (0.10 sec) mysql> show slave status \G; ............ ............ Slave_IO_Running: Yes Slave_SQL_Running: Yes 5) 在mysql-master主数据库上查看 mysql> show status like '%Rpl_semi%'; +--------------------------------------------+-------+ | Variable_name | Value | +--------------------------------------------+-------+ | Rpl_semi_sync_master_clients | 1 | | Rpl_semi_sync_master_net_avg_wait_time | 0 | | Rpl_semi_sync_master_net_wait_time | 0 | | Rpl_semi_sync_master_net_waits | 0 | | Rpl_semi_sync_master_no_times | 0 | | Rpl_semi_sync_master_no_tx | 0 | | Rpl_semi_sync_master_status | ON | | Rpl_semi_sync_master_timefunc_failures | 0 | | Rpl_semi_sync_master_tx_avg_wait_time | 0 | | Rpl_semi_sync_master_tx_wait_time | 0 | | Rpl_semi_sync_master_tx_waits | 0 | | Rpl_semi_sync_master_wait_pos_backtraverse | 0 | | Rpl_semi_sync_master_wait_sessions | 0 | | Rpl_semi_sync_master_yes_tx | 0 | +--------------------------------------------+-------+ 14 rows in set (0.00 sec) 从上面信息,发现Rpl_semi_sync_master_clients的数值为1,说明此时mysql-master主数据库已经有一个半同步复制的从机,即mysql-slave1节点。 Rpl_semi_sync_master_yes_tx的数值为0, 说明此时还没有半同步复制的sql语句被执行。 接着在mysql-master主数据库上插入和更新数据,测试半同步复制 mysql> select * from kevin.haha; +----+---------+ | id | name | +----+---------+ | 4 | beijing | | 5 | hefei | | 10 | xihu | | 21 | caiyi | | 22 | manman | | 23 | titi | +----+---------+ 6 rows in set (0.01 sec) mysql> insert into kevin.haha values(30,"shikui"),(31,"shibo"),(32,"shijuan"); Query OK, 3 rows affected (0.15 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> update kevin.haha set id=8 where name="beijing"; Query OK, 1 row affected (0.22 sec) Rows matched: 1 Changed: 1 Warnings: 0 接着再去mysql-slave1从数据库上查看,发现新数据已经同步过来了 mysql> select * from kevin.haha; +----+---------+ | id | name | +----+---------+ | 5 | hefei | | 8 | beijing | | 10 | xihu | | 21 | caiyi | | 22 | manman | | 23 | titi | | 30 | shikui | | 31 | shibo | | 32 | shijuan | +----+---------+ 9 rows in set (0.00 sec) 接着再去mysql-master主数据库上查看,如下: mysql> show status like '%Rpl_semi%'; +--------------------------------------------+--------+ | Variable_name | Value | +--------------------------------------------+--------+ | Rpl_semi_sync_master_clients | 1 | | Rpl_semi_sync_master_net_avg_wait_time | 0 | | Rpl_semi_sync_master_net_wait_time | 0 | | Rpl_semi_sync_master_net_waits | 2 | | Rpl_semi_sync_master_no_times | 0 | | Rpl_semi_sync_master_no_tx | 0 | | Rpl_semi_sync_master_status | ON | | Rpl_semi_sync_master_timefunc_failures | 0 | | Rpl_semi_sync_master_tx_avg_wait_time | 133362 | | Rpl_semi_sync_master_tx_wait_time | 266725 | | Rpl_semi_sync_master_tx_waits | 2 | | Rpl_semi_sync_master_wait_pos_backtraverse | 0 | | Rpl_semi_sync_master_wait_sessions | 0 | | Rpl_semi_sync_master_yes_tx | 2 | +--------------------------------------------+--------+ 14 rows in set (0.01 sec) 从上面信息可发现Rpl_semi_sync_master_yes_tx的数值为2,即发生了两条半同步复制的sql语句,就是上面执行的那两条(insert 和update) sql语句。
以上都是在mysql-master主数据库和mysql-slave1从数据库之间实现的基于GTID的主从复制、并行复制、半同步复制,即"一主一从"架构。 现在再把mysql-slave2的从节点添加进去,调整为"一主两从"的同步架构。添加操作记录如下:
1)在mysql-master主数据库上操作 先添加同步权限 mysql> grant replication slave,replication client on *.* to slave@'172.16.60.213' identified by "slave@123"; Query OK, 0 rows affected, 1 warning (0.14 sec) mysql> flush privileges; Query OK, 0 rows affected (0.14 sec) 备份主库 [root@mysql-master ~]# mysqldump -u root -p'123456' --lock-all-tables --master-data=2 --flush-logs --all-databases --triggers --routines --events > 213_slave.sql 将备份文件拷贝到mysql-slave2从数据库上 [root@mysql-master ~]# rsync -e "ssh -p22" -avpgolr /root/213_slave.sql root@172.16.60.213:/root/ 记录当前的gtid mysql> show global variables like 'gtid_%'; +----------------------------------+-------------------------------------------+ | Variable_name | Value | +----------------------------------+-------------------------------------------+ | gtid_executed | 317e2aad-1565-11e9-9c2e-005056ac6820:1-34 | | gtid_executed_compression_period | 1000 | | gtid_mode | ON | | gtid_owned | | | gtid_purged | 317e2aad-1565-11e9-9c2e-005056ac6820:1-16 | +----------------------------------+-------------------------------------------+ 5 rows in set (0.00 sec) 2)在mysql-slave2从数据库上操作 首先在my.cnf文件添加相关同步配置 (跟mysql-slave1从节点的my.cnf配置相比,除了将server_id修改为3之外,其他配置内容都一样!) [root@mysql-slave2 ~]# cp /etc/my.cnf /etc/my.cnf.bak [root@mysql-slave2 ~]# >/etc/my.cnf [root@mysql-slave2 ~]# vim /etc/my.cnf [mysqld] datadir = /var/lib/mysql socket = /var/lib/mysql/mysql.sock symbolic-links = 0 log-error = /var/log/mysqld.log pid-file = /var/run/mysqld/mysqld.pid #GTID: server_id = 3 gtid_mode = on enforce_gtid_consistency = on #binlog log_bin = mysql-bin log-slave-updates = 1 binlog_format = row sync-master-info = 1 sync_binlog = 1 #relay log skip_slave_start = 1 read_only = on #MTS slave-parallel-type = LOGICAL_CLOCK #开启逻辑时钟的复制 slave-parallel-workers = 4 #最大线程16 master_info_repository = TABLE relay_log_info_repository = TABLE relay_log_recovery = on # 开启半同步复制 plugin-load=rpl_semi_sync_slave=semisync_slave.so rpl_semi_sync_slave_enabled=1 配置完成后,不要忘记重启mysql服务 [root@mysql-slave2 ~]# systemctl restart mysqld 恢复备份库 [root@mysql-slave2 ~]# ll /root/213_slave.sql -rw-r--r-- 1 root root 805694 Jan 13 00:26 /root/213_slave.sql mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | +--------------------+ 4 rows in set (0.00 sec) mysql> source /root/213_slave.sql; mysql> select * from kevin.haha; +----+---------+ | id | name | +----+---------+ | 5 | hefei | | 8 | beijing | | 10 | xihu | | 21 | caiyi | | 22 | manman | | 23 | titi | | 30 | shikui | | 31 | shibo | | 32 | shijuan | +----+---------+ 9 rows in set (0.00 sec) 检查一下mysql-slave2从数据库上当前的gtid mysql> show global variables like 'gtid_%'; +----------------------------------+-------------------------------------------+ | Variable_name | Value | +----------------------------------+-------------------------------------------+ | gtid_executed | 317e2aad-1565-11e9-9c2e-005056ac6820:1-34 | | gtid_executed_compression_period | 1000 | | gtid_mode | ON | | gtid_owned | | | gtid_purged | 317e2aad-1565-11e9-9c2e-005056ac6820:1-34 | +----------------------------------+-------------------------------------------+ 5 rows in set (0.01 sec) 由于是从master-master主库备份恢复过来的,所以此时mysql-slave2从数据库的gtid和主库的gtid是一样的! 接着进行主从同步 mysql> stop slave; Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> change master to master_host='172.16.60.211',master_user='slave',master_password='slave@123',master_auto_position=1; Query OK, 0 rows affected, 2 warnings (0.18 sec) mysql> start slave; Query OK, 0 rows affected (0.17 sec) ================================================================= 如果遇到报错: ERROR 1872 (HY000): Slave failed to initialize relay log info structure from the repository 解决办法: stop slave; reset slave; start slave; ================================================================= 查看,发现主从同步正常 mysql> show slave status \G; ......... Slave_IO_Running: Yes Slave_SQL_Running: Yes 并行复制查看 mysql> show variables like '%slave_para%'; +------------------------+---------------+ | Variable_name | Value | +------------------------+---------------+ | slave_parallel_type | LOGICAL_CLOCK | | slave_parallel_workers | 4 | +------------------------+---------------+ 2 rows in set (0.01 sec) mysql> select * from mysql.slave_worker_info; +----+----------------+---------------+-----------------+----------------+---------------------------+--------------------------+----------------------------+---------------------------+------------------+-----------------------+------------------------------------------------------------------+--------------+ | Id | Relay_log_name | Relay_log_pos | Master_log_name | Master_log_pos | Checkpoint_relay_log_name | Checkpoint_relay_log_pos | Checkpoint_master_log_name | Checkpoint_master_log_pos | Checkpoint_seqno | Checkpoint_group_size | Checkpoint_group_bitmap | Channel_name | +----+----------------+---------------+-----------------+----------------+---------------------------+--------------------------+----------------------------+---------------------------+------------------+-----------------------+------------------------------------------------------------------+--------------+ | 1 | | 0 | | 0 | | 0 | | 0 | 0 | 64 | | | | 2 | | 0 | | 0 | | 0 | | 0 | 0 | 64 | | | | 3 | | 0 | | 0 | | 0 | | 0 | 0 | 64 | | | | 4 | | 0 | | 0 | | 0 | | 0 | 0 | 64 | | | +----+----------------+---------------+-----------------+----------------+---------------------------+--------------------------+----------------------------+---------------------------+------------------+-----------------------+------------------------------------------------------------------+--------------+ 4 rows in set (0.00 sec) 接着在mysql-slave2从数据库上开启半同步 mysql> INSTALL PLUGIN rpl_semi_sync_slave SONAME 'semisync_slave.so'; Query OK, 0 rows affected (0.03 sec) mysql> SELECT PLUGIN_NAME, PLUGIN_STATUS FROM INFORMATION_SCHEMA.PLUGINS WHERE PLUGIN_NAME LIKE '%semi%'; +---------------------+---------------+ | PLUGIN_NAME | PLUGIN_STATUS | +---------------------+---------------+ | rpl_semi_sync_slave | ACTIVE | +---------------------+---------------+ 1 row in set (0.00 sec) mysql> STOP SLAVE IO_THREAD; Query OK, 0 rows affected (0.02 sec) mysql> START SLAVE IO_THREAD; Query OK, 0 rows affected (0.00 sec) mysql> show status like 'Rpl_semi_sync_slave_status'; +----------------------------+-------+ | Variable_name | Value | +----------------------------+-------+ | Rpl_semi_sync_slave_status | ON | +----------------------------+-------+ 1 row in set (0.00 sec) 3) 现在回到mysql-master主数据库查看 mysql> show slave hosts; +-----------+------+------+-----------+--------------------------------------+ | Server_id | Host | Port | Master_id | Slave_UUID | +-----------+------+------+-----------+--------------------------------------+ | 3 | | 3306 | 1 | 2658b203-1565-11e9-9f8b-005056880888 | | 2 | | 3306 | 1 | 2c1efc46-1565-11e9-ab8e-00505688047c | +-----------+------+------+-----------+--------------------------------------+ 2 rows in set (0.00 sec) 如上信息可知mysql-master主数据库现在有两个从数据库,分别为mysql-slave1 和 mysql-slave2 mysql> show status like '%Rpl_semi%'; +--------------------------------------------+--------+ | Variable_name | Value | +--------------------------------------------+--------+ | Rpl_semi_sync_master_clients | 2 | | Rpl_semi_sync_master_net_avg_wait_time | 0 | | Rpl_semi_sync_master_net_wait_time | 0 | | Rpl_semi_sync_master_net_waits | 4 | | Rpl_semi_sync_master_no_times | 0 | | Rpl_semi_sync_master_no_tx | 0 | | Rpl_semi_sync_master_status | ON | | Rpl_semi_sync_master_timefunc_failures | 0 | | Rpl_semi_sync_master_tx_avg_wait_time | 98077 | | Rpl_semi_sync_master_tx_wait_time | 392310 | | Rpl_semi_sync_master_tx_waits | 4 | | Rpl_semi_sync_master_wait_pos_backtraverse | 0 | | Rpl_semi_sync_master_wait_sessions | 0 | | Rpl_semi_sync_master_yes_tx | 4 | +--------------------------------------------+--------+ 14 rows in set (0.00 sec) 如上信息可知,mysql-master主数据库现在有两个半同步复制的从库,即mysql-slave1 和mysql-slave2 4)现在测试下同步效果 在mysql-master主数据库上更新数据 mysql> delete from kevin.haha where id>10; Query OK, 6 rows affected (0.20 sec) mysql> insert into kevin.haha values(11,"changping"),(12,"wangjing"); Query OK, 2 rows affected (0.38 sec) Records: 2 Duplicates: 0 Warnings: 0 在mysql-slave1从数据库查看,发现已经同步过来了 mysql> select * from kevin.haha; +----+-----------+ | id | name | +----+-----------+ | 5 | hefei | | 8 | beijing | | 10 | xihu | | 11 | changping | | 12 | wangjing | +----+-----------+ 5 rows in set (0.00 sec) 在mysql-slave2从数据库查看,发现已经同步过来了 mysql> select * from kevin.haha; +----+-----------+ | id | name | +----+-----------+ | 5 | hefei | | 8 | beijing | | 10 | xihu | | 11 | changping | | 12 | wangjing | +----+-----------+ 5 rows in set (0.00 sec)
到此,已经完成了Mysql5.7"一主两从"架构上基于GTID主从复制+并行复制+增强半同步复制环境,下面再说下读写分离环境:
六、读写分离 (MySQL ProxySQL)
ProxySQL是用C++语言开发的,也是percona推的一款中间件,虽然也是一个轻量级产品,但性能很好(据测试,能处理千亿级的数据),功能也足够,能满足中间件所需的绝大多数功能,包括:
- 最基本的读写分离,且安装起来也十分方便。
- 可定制基于用户、基于schema、基于语句的规则对SQL语句进行路由。换句话说,规则很灵活。基于schema和与语句级的规则,可以实现简单的sharding。
- 可缓存查询结果。虽然ProxySQL的缓存策略比较简陋,但实现了基本的缓存功能,绝大多数时候也够用了。此外,作者已经打算实现更丰富的缓存策略。
- 监控后端节点。ProxySQL可以监控后端节点的多个指标,包括:ProxySQL和后端的心跳信息,后端节点的read-only/read-write,slave和master的数据同步延迟性(replication lag)。
ProxySQL是一个能实实在在用在生产环境的MySQL中间件,可以实现读写分离,支持 Query 路由功能,支持动态指定某个 SQL 进行 cache,支持动态加载配置、故障切换和一些 SQL的过滤功能。还有一些同类产品比如 DBproxy、MyCAT、OneProxy 等。但经过反复对比和测试之后,还是觉得ProxySQL是一款性能不谙,靠谱稳定的MySQL 中间件产品 !
ProxySQL读写分离环境部署记录
下面操作是在mysql-proxy代理层节点上完成的(需要注意: 两个从库都要开启 read_only=on):
1)先在本机安装mysql客户端,用于在本机连接到ProxySQL的管理接口
[root@mysql-proxy ~]# vim /etc/yum.repos.d/mariadb.repo [mariadb] name = MariaDB baseurl = http://yum.mariadb.org/10.3.5/centos6-amd64 gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDB gpgcheck=1 安装mysql-clinet客户端 [root@mysql-proxy ~]# yum install -y MariaDB-client ================================================= 如果遇到报错: Error: MariaDB-compat conflicts with 1:mariadb-libs-5.5.60-1.el7_5.x86_64 You could try using --skip-broken to work around the problem You could try running: rpm -Va --nofiles --nodigest 解决办法: [root@mysql-proxy ~]# rpm -qa|grep mariadb* mariadb-libs-5.5.56-2.el7.x86_64 [root@mysql-proxy ~]# rpm -e mariadb-libs-5.5.56-2.el7.x86_64 --nodeps [root@mysql-proxy ~]# yum install -y MariaDB-client
2)安装ProxySQL (中文安装手册: https://github.com/malongshuai/proxysql/wiki)
[root@mysql-proxy ~]# vim /etc/yum.repos.d/proxysql.repo [proxysql_repo] name= ProxySQL YUM repository baseurl=http://repo.proxysql.com/ProxySQL/proxysql-1.4.x/centos/\$releasever gpgcheck=1 gpgkey=http://repo.proxysql.com/ProxySQL/repo_pub_key 执行安装 [root@mysql-proxy ~]# yum -y install proxysql [root@mysql-proxy ~]# proxysql --version ProxySQL version 1.4.13-15-g69d4207, codename Truls 启动ProxySQL [root@mysql-proxy ~]# chkconfig proxysql on [root@mysql-proxy ~]# systemctl start proxysql [root@mysql-proxy ~]# systemctl status proxysql 启动后会监听两个端口, 默认为6032和6033。6032端口是ProxySQL的管理端口,6033是ProxySQL对外提供服务的端口 (即连接到转发后端的真正数据库的转发端口)。 [root@mysql-proxy ~]# netstat -tunlp Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:6032 0.0.0.0:* LISTEN 23940/proxysql tcp 0 0 0.0.0.0:6033 0.0.0.0:* LISTEN 23940/proxysql
3)向ProxySQL中添加MySQL节点
ProxySQL也是有管理接口和客户端接口,通过配置文件/etc/proxysql.cnf可以看到管理和客户端接口的信息. [root@mysql-proxy ~]# cat /etc/proxysql.cnf ......... admin_variables= { admin_credentials="admin:admin" # mysql_ifaces="127.0.0.1:6032;/tmp/proxysql_admin.sock" mysql_ifaces="0.0.0.0:6032" # refresh_interval=2000 # debug=true } mysql_variables= { threads=4 max_connections=2048 default_query_delay=0 default_query_timeout=36000000 have_compress=true poll_timeout=2000 # interfaces="0.0.0.0:6033;/tmp/proxysql.sock" interfaces="0.0.0.0:6033" default_schema="information_schema" stacksize=1048576 server_version="5.5.30" connect_timeout_server=3000 .......... 通过上面,可以看到管理接口的端口是6032,账号密码是admin(可以动态修改),允许客户端连接, 客户端接口的端口是6033,账号密码通过管理接口去设置。 在mysql-proxy本机使用mysql客户端连接到ProxySQL的管理接口(admin interface), 该接口的默认管理员用户和密码都是admin. 下面是通过管理端口6032去连接的(下面连接命令中后面的--prompt 'admin'字段可以不加,也是可以登录进去的) [root@mysql-proxy ~]# mysql -uadmin -padmin -P6032 -h127.0.0.1 --prompt 'admin> ' Welcome to the MariaDB monitor. Commands end with ; or \g. Your MySQL connection id is 8 Server version: 5.5.30 (ProxySQL Admin Module) Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. admin> show databases; +-----+---------------+-------------------------------------+ | seq | name | file | +-----+---------------+-------------------------------------+ | 0 | main | | | 2 | disk | /var/lib/proxysql/proxysql.db | | 3 | stats | | | 4 | monitor | | | 5 | stats_history | /var/lib/proxysql/proxysql_stats.db | +-----+---------------+-------------------------------------+ 5 rows in set (0.001 sec) ProxySQL提供了几个库,每个库都有各自的意义; - main 内存配置数据库,表里存放后端db实例、用户验证、路由规则等信息。表名以 runtime_开头的表示proxysql当前运行的配置内容, 不能通过dml语句修改,只能修改对应的不以 runtime_ 开头的(在内存)里的表,然后 LOAD 使其生效, SAVE 使其存到硬盘以供下次重启加载。 - disk 是持久化到硬盘的配置,sqlite数据文件。 - stats 是proxysql运行抓取的统计信息,包括到后端各命令的执行次数、流量、processlist、查询种类汇总/执行时间等等。 - monitor 库存储 monitor 模块收集的信息,主要是对后端db的健康/延迟检查。 主要注意main和monitor数据库中的表 admin> show tables from main; +--------------------------------------------+ | tables | +--------------------------------------------+ | global_variables | | mysql_collations | | mysql_group_replication_hostgroups | | mysql_query_rules | | mysql_query_rules_fast_routing | | mysql_replication_hostgroups | | mysql_servers | | mysql_users | | proxysql_servers | | runtime_checksums_values | | runtime_global_variables | | runtime_mysql_group_replication_hostgroups | | runtime_mysql_query_rules | | runtime_mysql_query_rules_fast_routing | | runtime_mysql_replication_hostgroups | | runtime_mysql_servers | | runtime_mysql_users | | runtime_proxysql_servers | | runtime_scheduler | | scheduler | +--------------------------------------------+ 20 rows in set (0.001 sec) 几个重要字段含义: global_variables 设置变量,包括监听的端口、管理账号等。 mysql_collations 相关字符集和校验规则。 mysql_query_rules 定义查询路由规则。 admin> show tables from monitor; +------------------------------------+ | tables | +------------------------------------+ | mysql_server_connect_log | | mysql_server_group_replication_log | | mysql_server_ping_log | | mysql_server_read_only_log | | mysql_server_replication_lag_log | +------------------------------------+ 5 rows in set (0.000 sec) runtime_开头的是运行时的配置,这些是不能修改的。要修改ProxySQL的配置,需要修改了非runtime_表,修改后必须执行LOAD ... TO RUNTIME 才能加载到RUNTIME生效,执行save ... to disk才能将配置持久化保存到磁盘。 使用insert语句添加主机到mysql_servers表中,其中:hostgroup_id 10 表示写组,20表示读组。 admin> insert into mysql_servers(hostgroup_id,hostname,port) values(10,'172.16.60.211',3306); Query OK, 1 row affected (0.001 sec) admin> insert into mysql_servers(hostgroup_id,hostname,port) values(10,'172.16.60.212',3306); Query OK, 1 row affected (0.000 sec) admin> insert into mysql_servers(hostgroup_id,hostname,port) values(10,'172.16.60.213',3306); Query OK, 1 row affected (0.000 sec) 查看这3个节点是否插入成功,以及它们的状态。 admin> select * from mysql_servers\G; *************************** 1. row *************************** hostgroup_id: 10 hostname: 172.16.60.211 port: 3306 status: ONLINE weight: 1 compression: 0 max_connections: 1000 max_replication_lag: 0 use_ssl: 0 max_latency_ms: 0 comment: *************************** 2. row *************************** hostgroup_id: 10 hostname: 172.16.60.212 port: 3306 status: ONLINE weight: 1 compression: 0 max_connections: 1000 max_replication_lag: 0 use_ssl: 0 max_latency_ms: 0 comment: *************************** 3. row *************************** hostgroup_id: 10 hostname: 172.16.60.213 port: 3306 status: ONLINE weight: 1 compression: 0 max_connections: 1000 max_replication_lag: 0 use_ssl: 0 max_latency_ms: 0 comment: 3 rows in set (0.000 sec) ERROR: No query specified admin> 如上修改后,加载到RUNTIME,并保存到disk admin> load mysql servers to runtime; Query OK, 0 rows affected (0.005 sec) admin> save mysql servers to disk; Query OK, 0 rows affected (0.468 sec)
4)监控后端MySQL节点
如上添加Mysql节点之后,还需要监控这些后端节点。对于后端是主从复制的环境来说,这是必须的,因为ProxySQL需要通过每个节点的read_only值来自动调整 它们是属于读组还是写组。 首先在后端master主数据节点上创建一个用于监控的用户名(只需在master上创建即可,因为会复制到slave上),这个用户名只需具有USAGE权限即可。如果还需 要监控复制结构中slave是否严重延迟于master(这个俗语叫做"拖后腿",术语叫做"replication lag"),则还需具备replication client权限。 即在mysql-master主数据库节点行执行: mysql> create user monitor@'172.16.60.%' identified by 'P@ssword1!'; Query OK, 0 rows affected (0.08 sec) mysql> grant replication client on *.* to monitor@'172.16.60.%'; Query OK, 0 rows affected (0.07 sec) mysql> flush privileges; Query OK, 0 rows affected (0.07 sec) 然后回到mysql-proxy代理层节点上配置监控 admin> set mysql-monitor_username='monitor'; Query OK, 1 row affected (0.001 sec) admin> set mysql-monitor_password='P@ssword1!'; Query OK, 1 row affected (0.000 sec) 修改后,加载到RUNTIME,并保存到disk admin> load mysql variables to runtime; Query OK, 0 rows affected (0.001 sec) admin> save mysql variables to disk; Query OK, 96 rows affected (0.180 sec) 验证监控结果:ProxySQL监控模块的指标都保存在monitor库的log表中。 以下是连接是否正常的监控(对connect指标的监控):(在前面可能会有很多connect_error,这是因为没有配置监控信息时的错误, 配置后如果connect_error的结果为NULL则表示正常) admin> select * from mysql_server_connect_log; +---------------+------+------------------+-------------------------+------------------------------------------------------------------------+ | hostname | port | time_start_us | connect_success_time_us | connect_error | +---------------+------+------------------+-------------------------+------------------------------------------------------------------------+ | 172.16.60.213 | 3306 | 1547436747566683 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.211 | 3306 | 1547436748167350 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547436748767837 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547436807566915 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.211 | 3306 | 1547436808112262 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.213 | 3306 | 1547436808657603 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.213 | 3306 | 1547436867566829 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.211 | 3306 | 1547436868151063 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547436868735236 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547436927567060 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.211 | 3306 | 1547436928247532 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.213 | 3306 | 1547436928927772 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.211 | 3306 | 1547436987567058 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547436988049160 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.213 | 3306 | 1547436988531003 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.212 | 3306 | 1547437047567194 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.213 | 3306 | 1547437048132480 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.211 | 3306 | 1547437048697765 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.211 | 3306 | 1547437107567258 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547437108310411 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.213 | 3306 | 1547437109053480 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.213 | 3306 | 1547437167567303 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.211 | 3306 | 1547437168158076 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547437168748763 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.213 | 3306 | 1547437227567525 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.211 | 3306 | 1547437228288921 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547437229010153 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.211 | 3306 | 1547437287567412 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547437288343609 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.213 | 3306 | 1547437289119851 | 0 | Access denied for user 'monitor'@'docker-node2' (using password: YES) | | 172.16.60.213 | 3306 | 1547437295397678 | 1388 | NULL | | 172.16.60.211 | 3306 | 1547437295826682 | 1377 | NULL | | 172.16.60.212 | 3306 | 1547437296255659 | 8072 | NULL | +---------------+------+------------------+-------------------------+------------------------------------------------------------------------+ 33 rows in set (0.001 sec) 以下是对心跳信息的监控(对ping指标的监控) admin> select * from mysql_server_ping_log; +---------------+------+------------------+----------------------+------------------------------------------------------------------------+ | hostname | port | time_start_us | ping_success_time_us | ping_error | +---------------+------+------------------+----------------------+------------------------------------------------------------------------+ | 172.16.60.213 | 3306 | 1547436798804839 | 0 | Access denied for user 'monitor'@'172.16.60.213' (using password: YES) | | 172.16.60.211 | 3306 | 1547436798875555 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.212 | 3306 | 1547436798946212 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.213 | 3306 | 1547436808804803 | 0 | Access denied for user 'monitor'@'172.16.60.213' (using password: YES) | | 172.16.60.212 | 3306 | 1547436808931415 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | | 172.16.60.211 | 3306 | 1547436809058082 | 0 | Access denied for user 'monitor'@'172.16.60.214' (using password: YES) | .................... .................... | 172.16.60.213 | 3306 | 1547437295030407 | 335 | NULL | | 172.16.60.211 | 3306 | 1547437295159540 | 218 | NULL | | 172.16.60.212 | 3306 | 1547437295288638 | 172 | NULL | | 172.16.60.211 | 3306 | 1547437365241682 | 337 | NULL | | 172.16.60.211 | 3306 | 1547437375031403 | 435 | NULL | .................. .................. | 172.16.60.213 | 3306 | 1547437395160777 | 469 | NULL | | 172.16.60.211 | 3306 | 1547437395289919 | 377 | NULL | +---------------+------+------------------+----------------------+------------------------------------------------------------------------+ 183 rows in set (0.001 sec) 但是,read_only和replication_lag的监控日志都为空。 admin> select * from mysql_server_read_only_log; Empty set (0.000 sec) admin> select * from mysql_server_replication_lag_log; Empty set (0.000 sec) 例如,指定写组的id为10,读组的id为20。 admin> insert into mysql_replication_hostgroups values(10,20,1); Query OK, 1 row affected (0.000 sec) 在该配置加载到RUNTIME生效之前,先查看下各mysql server所在的组。 admin> select hostgroup_id,hostname,port,status,weight from mysql_servers; +--------------+---------------+------+--------+--------+ | hostgroup_id | hostname | port | status | weight | +--------------+---------------+------+--------+--------+ | 10 | 172.16.60.211 | 3306 | ONLINE | 1 | | 10 | 172.16.60.212 | 3306 | ONLINE | 1 | | 10 | 172.16.60.213 | 3306 | ONLINE | 1 | +--------------+---------------+------+--------+--------+ 3 rows in set (0.000 sec) 3个节点都在hostgroup_id=10的组中。 现在,将刚才mysql_replication_hostgroups表的修改加载到RUNTIME生效。 admin> load mysql servers to runtime; Query OK, 0 rows affected (0.005 sec) admin> save mysql servers to disk; Query OK, 0 rows affected (0.406 sec) 一加载,Monitor模块就会开始监控后端的read_only值,当监控到read_only值后,就会按照read_only的值将某些节点自动移动到读/写组。 例如,此处所有节点都在id=10的写组,slave1和slave2都是slave,它们的read_only=1,这两个节点将会移动到id=20的组。 如果一开始这3节点都在id=20的读组,那么移动的将是Master节点,会移动到id=10的写组。 现在看结果 admin> select hostgroup_id,hostname,port,status,weight from mysql_servers; +--------------+---------------+------+--------+--------+ | hostgroup_id | hostname | port | status | weight | +--------------+---------------+------+--------+--------+ | 10 | 172.16.60.211 | 3306 | ONLINE | 1 | | 20 | 172.16.60.212 | 3306 | ONLINE | 1 | | 20 | 172.16.60.213 | 3306 | ONLINE | 1 | +--------------+---------------+------+--------+--------+ 3 rows in set (0.000 sec) admin> select * from mysql_server_read_only_log; +---------------+------+------------------+-----------------+-----------+-------+ | hostname | port | time_start_us | success_time_us | read_only | error | +---------------+------+------------------+-----------------+-----------+-------+ | 172.16.60.212 | 3306 | 1547438982938183 | 694 | 1 | NULL | | 172.16.60.211 | 3306 | 1547438982950903 | 741 | 0 | NULL | .............. .............. | 172.16.60.211 | 3306 | 1547439054961006 | 517 | 0 | NULL | | 172.16.60.213 | 3306 | 1547439054977658 | 479 | 1 | NULL | +---------------+------+------------------+-----------------+-----------+-------+ 147 rows in set (0.001 sec)
5)配置mysql_users
上面的所有配置都是关于后端MySQL节点的,现在可以配置关于SQL语句的,包括:发送SQL语句的用户、SQL语句的路由规则、SQL查询的缓存、 SQL语句的重写等等。本小节是SQL请求所使用的用户配置,例如root用户。这要求我们需要先在后端MySQL节点添加好相关用户。这里以root和 sqlsender两个用户名为例。 首先,在mysql-master主数据库节点上执行:(只需master执行即可,会复制给两个slave) mysql> grant all on *.* to root@'172.16.60.%' identified by 'passwd'; Query OK, 0 rows affected, 1 warning (0.06 sec) mysql> grant all on *.* to sqlsender@'172.16.60.%' identified by 'P@ssword1!'; Query OK, 0 rows affected, 1 warning (0.15 sec) mysql> flush privileges; Query OK, 0 rows affected (0.06 sec) 然后回到mysql-proxy代理层节点,配置mysql_users表,将刚才的两个用户添加到该表中。 admin> insert into mysql_users(username,password,default_hostgroup) values('root','passwd',10); Query OK, 1 row affected (0.001 sec) admin> insert into mysql_users(username,password,default_hostgroup) values('sqlsender','P@ssword1!',10); Query OK, 1 row affected (0.000 sec) admin> load mysql users to runtime; Query OK, 0 rows affected (0.001 sec) admin> save mysql users to disk; Query OK, 0 rows affected (0.108 sec) mysql_users表有不少字段,最主要的三个字段为username、password和default_hostgroup: - username:前端连接ProxySQL,以及ProxySQL将SQL语句路由给MySQL所使用的用户名。 - password:用户名对应的密码。可以是明文密码,也可以是hash密码。如果想使用hash密码,可以先在某个MySQL节点上执行 select password(PASSWORD),然后将加密结果复制到该字段。 - default_hostgroup:该用户名默认的路由目标。例如,指定root用户的该字段值为10时,则使用root用户发送的SQL语句默认 情况下将路由到hostgroup_id=10组中的某个节点。 admin> select * from mysql_users\G *************************** 1. row *************************** username: root password: passwd active: 1 use_ssl: 0 default_hostgroup: 10 default_schema: NULL schema_locked: 0 transaction_persistent: 1 fast_forward: 0 backend: 1 frontend: 1 max_connections: 10000 *************************** 2. row *************************** username: sqlsender password: P@ssword1! active: 1 use_ssl: 0 default_hostgroup: 10 default_schema: NULL schema_locked: 0 transaction_persistent: 1 fast_forward: 0 backend: 1 frontend: 1 max_connections: 10000 2 rows in set (0.000 sec) 虽然这里没有详细介绍mysql_users表,但上面标注了"注意本行"的两个字段必须要引起注意。只有active=1的用户才是有效的用户。 至于transaction_persistent字段,当它的值为1时,表示事务持久化:当某连接使用该用户开启了一个事务后,那么在事务提交/回滚之前, 所有的语句都路由到同一个组中,避免语句分散到不同组。在以前的版本中,默认值为0,不知道从哪个版本开始,它的默认值为1。 我们期望的值为1,所以在继续下面的步骤之前,先查看下这个值,如果为0,则执行下面的语句修改为1。 admin> update mysql_users set transaction_persistent=1 where username='root'; Query OK, 1 row affected (0.000 sec) admin> update mysql_users set transaction_persistent=1 where username='sqlsender'; Query OK, 1 row affected (0.000 sec) admin> load mysql users to runtime; Query OK, 0 rows affected (0.001 sec) admin> save mysql users to disk; Query OK, 0 rows affected (0.098 sec) 然后,另开一个终端,分别使用root用户和sqlsender用户测试下它们是否能路由到默认的hostgroup_id=10(它是一个写组)读、写数据。 [root@mysql-proxy ~]# mysql -uroot -ppasswd -P6033 -h127.0.0.1 -e "select @@server_id" #这是通过转发端口6033连接的,连接的是转发到后端真正的数据库! +-------------+ | @@server_id | +-------------+ | 1 | +-------------+ [root@mysql-proxy ~]# mysql -uroot -ppasswd -P6033 -h127.0.0.1 -e "create database proxy_test" [root@mysql-proxy ~]# mysql -uroot -ppasswd -P6033 -h127.0.0.1 -e "show databases;" +--------------------+ | Database | +--------------------+ | information_schema | | kevin | | mysql | | performance_schema | | proxy_test | | sys | +--------------------+ [root@mysql-proxy ~]# mysql -usqlsender -pP@ssword1! -P6033 -h127.0.0.1 -e 'use proxy_test;create table t(id int);' [root@mysql-proxy ~]# mysql -usqlsender -pP@ssword1! -P6033 -h127.0.0.1 -e 'show tables from proxy_test;' +----------------------+ | Tables_in_proxy_test | +----------------------+ | t | +----------------------+
6)读写分离:配置路由规则
ProxySQL的路由规则非常灵活,可以基于用户、基于schema以及基于每个语句实现路由规则的定制。本案例作为一个入门配置,实现一个最简单的语句级路由规则,从而实现读写分离。 必须注意,这只是实验,实际的路由规则绝不应该仅根据所谓的读、写操作进行分离,而是从各项指标中找出压力大、执行频繁的语句单独写规则、做缓存等等。和查询规则有关的表有两个: mysql_query_rules和mysql_query_rules_fast_routing,后者是前者的扩展表,1.4.7之后才支持该快速路由表。本案例只介绍第一个表。插入两个规则,目的是将select语句分离到 hostgroup_id=20的读组,但由于select语句中有一个特殊语句SELECT...FOR UPDATE它会申请写锁,所以应该路由到hostgroup_id=10的写组。 admin> insert into mysql_query_rules(rule_id,active,match_digest,destination_hostgroup,apply) VALUES (1,1,'^SELECT.*FOR UPDATE$',10,1), (2,1,'^SELECT',20,1); Query OK, 2 rows affected (0.001 sec) admin> load mysql query rules to runtime; Query OK, 0 rows affected (0.000 sec) admin> save mysql query rules to disk; Query OK, 0 rows affected (0.179 sec) 需要注意: select ... for update规则的rule_id必须要小于普通的select规则的rule_id,因为ProxySQL是根据rule_id的顺序进行规则匹配的。 再来测试下,读操作是否路由给了hostgroup_id=20的读组。 [root@mysql-proxy ~]# mysql -uroot -ppasswd -P6033 -h127.0.0.1 -e 'select @@server_id' +-------------+ | @@server_id | +-------------+ | 3 | +-------------+ [root@mysql-proxy ~]# mysql -uroot -ppasswd -P6033 -h127.0.0.1 -e 'select @@server_id' +-------------+ | @@server_id | +-------------+ | 2 | +-------------+ 读操作已经路由给读组,再看看写操作。这里以事务持久化进行测试。 [root@mysql-proxy ~]# mysql -uroot -ppasswd -P6033 -h127.0.0.1 -e 'start transaction;select @@server_id;commit;select @@server_id;' +-------------+ | @@server_id | +-------------+ | 1 | +-------------+ +-------------+ | @@server_id | +-------------+ | 3 | +-------------+ 显然,一切都按照预期进行。最后,如果想查看路由的信息,可查询stats库中的stats_mysql_query_digest表。 以下是该表的一个输出格式示例(和本案例无关)。 admin> SELECT hostgroup hg, sum_time, count_star, digest_text FROM stats_mysql_query_digest ORDER BY sum_time DESC; +----+----------+------------+----------------------------------+ | hg | sum_time | count_star | digest_text | +----+----------+------------+----------------------------------+ | 10 | 236771 | 1 | create table t(id int) | | 10 | 53767 | 1 | create database proxy_test | | 20 | 10344 | 1 | select @@server_id | | 20 | 3350 | 3 | select @@server_id | | 10 | 2469 | 2 | SELECT DATABASE() | | 10 | 1678 | 2 | select @@server_id | | 10 | 1193 | 1 | show databases | | 10 | 1191 | 1 | start transaction | | 10 | 815 | 1 | show tables from proxy_test | | 10 | 289 | 1 | reate table t(id int) | | 10 | 162 | 1 | commit | | 10 | 0 | 6 | select @@version_comment limit ? | | 10 | 0 | 4 | select @@version_comment limit ? | | 10 | 0 | 1 | select @@version_comment limit ? | +----+----------+------------+----------------------------------+ 14 rows in set (0.002 sec)
7)最后测试通过proxysql插件进行读写分离
mysql-master主数据库查看 mysql> select * from kevin.haha; +----+-----------+ | id | name | +----+-----------+ | 5 | hefei | | 8 | beijing | | 10 | xihu | | 11 | changping | | 12 | wangjing | +----+-----------+ 5 rows in set (0.00 sec) mysql-slave1和mysql-slave2两个从数据库查看 mysql> select * from kevin.haha; +----+-----------+ | id | name | +----+-----------+ | 5 | hefei | | 8 | beijing | | 10 | xihu | | 11 | changping | | 12 | wangjing | +----+-----------+ 5 rows in set (0.00 sec) 在mysql-proxy代理层节点,通过proxysql进行数据写入,并查看 [root@mysql-proxy ~]# mysql -uroot -ppasswd -P6033 -h127.0.0.1 -e 'insert into kevin.haha values(21,"zhongguo"),(22,"xianggang"),(23,"taiwan");' [root@mysql-proxy ~]# mysql -uroot -ppasswd -P6033 -h127.0.0.1 -e 'delete from kevin.haha where id=10' [root@mysql-proxy ~]# mysql -uroot -ppasswd -P6033 -h127.0.0.1 -e 'select * from kevin.haha;' +----+-----------+ | id | name | +----+-----------+ | 5 | hefei | | 8 | beijing | | 11 | changping | | 12 | wangjing | | 21 | zhongguo | | 22 | xianggang | | 23 | taiwan | 在mysql-master主数据库节点查看 mysql> select * from kevin.haha; +----+-----------+ | id | name | +----+-----------+ | 5 | hefei | | 8 | beijing | | 11 | changping | | 12 | wangjing | | 21 | zhongguo | | 22 | xianggang | | 23 | taiwan | +----+-----------+ 7 rows in set (0.00 sec) 在mysql-slave1和mysql-slave2从数据库节点查看 mysql> select * from kevin.haha; +----+-----------+ | id | name | +----+-----------+ | 5 | hefei | | 8 | beijing | | 11 | changping | | 12 | wangjing | | 21 | zhongguo | | 22 | xianggang | | 23 | taiwan | +----+-----------+ 7 rows in set (0.00 sec) 发现在客户端通过proxysql插件更新的数据,已经写到mysql-master主数据库上,并同步到mysql-slave1和mysql-slave2两个从数据库上了! ==========================需要注意======================= 上面测试的客户机是在mysql-proxy本机,所以用127.0.0.1. 如果是在别的客户机上,那么连接命令中就用proxysql的地址,即"mysql -uroot -ppasswd -P6033 -h172.16.60.214" 比如在mysql-slave2机器上连接proxysql插件: [root@mysql-slave2 ~]# mysql -uroot -ppasswd -P6033 -h172.16.60.214 mysql: [Warning] Using a password on the command line interface can be insecure. Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 47 Server version: 5.5.30 (ProxySQL) Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | kevin | | mysql | | performance_schema | | proxy_test | | sys | +--------------------+ 6 rows in set (0.00 sec) 删除上面创建的proxy_test测试库 mysql> drop database proxy_test; Query OK, 1 row affected (0.16 sec) mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | kevin | | mysql | | performance_schema | | sys | +--------------------+ 5 rows in set (0.00 sec) mysql> select * from kevin.haha; +----+-----------+ | id | name | +----+-----------+ | 5 | hefei | | 8 | beijing | | 11 | changping | | 12 | wangjing | | 21 | zhongguo | | 22 | xianggang | | 23 | taiwan | +----+-----------+ 7 rows in set (0.00 sec)
至此,MySQL5.7基于GTID主从复制+并行复制+半同步复制+读写分离的环境部署工作已完成。