By 兰春

Updated:

Contents
  1. 1. 18.2.1 Deploying Group Replication in Single-Primary Mode
    1. 1.1. 18.2.1.1 Deploying Instances for Group Replication
    2. 1.2. 18.2.1.2 Configuring an Instance for Group Replication
    3. 1.3. 18.2.1.3 User Credentials
    4. 1.4. 18.2.1.4 Launching Group Replication
    5. 1.5. 18.2.1.5 Adding Instances to the Group

https://dev.mysql.com/doc/refman/8.0/en/group-replication-getting-started.html

MGR 作为一个Server插件提供支持的，每个group的server都需要配置和加载这个插件
这一章主要教大家在三节点的MGR环境下，怎么一步步搭建起来的

18.2.1 Deploying Group Replication in Single-Primary Mode

每个group中的实例既可以是在单独的物理机部署，也可以在同一台物理机部署
这一节主要描述怎么在同一个物理机部署MGR

  • Figure 18.4 Group Architecture

MGR

这个教程主要描述如何部署MGR，在构建MGR前如何配置每个实例，以及如何使用Performance Schema 来监控MGR正确运行

18.2.1.1 Deploying Instances for Group Replication

第一步：部署三个MySQL实例
由于接下来的步骤是在同一台物理机搭建多个实例的，因此每个MySQL实例都必须要指定一个特定的数据目录 

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mkdir data  
mysql-8.0/bin/mysqld --initialize-insecure --basedir=$PWD/mysql-8.0 --datadir=$PWD/data/s1  
mysql-8.0/bin/mysqld --initialize-insecure --basedir=$PWD/mysql-8.0 --datadir=$PWD/data/s2  
mysql-8.0/bin/mysqld --initialize-insecure --basedir=$PWD/mysql-8.0 --datadir=$PWD/data/s3

在data/s1，data/s2，data/s3 里面都是初始化好的数据目录，里面有mysql 系统库等等 

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warnings:
不要在生产环境使用--initialize-insecure ，这里只是用来简化教程的，详情请看：
Section 18.5, “Group Replication Security”.

18.2.1.2 Configuring an Instance for Group Replication

  • Group Replication Server Settings

安装和使用MGR插件，你必须正确配置MySQL Server才行
下面的配置将是你的MGR第一个实例的配置S1 

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[mysqld]
# server configuration
datadir=<full_path_to_data>/data/s1
basedir=<full_path_to_bin>/mysql-8.0/
port=24801
socket=<full_path_to_sock_dir>/s1.sock

如果你的三个实例都在一个机器上，那么你应该配置report_host=127.0.0.1 ， 让其互相可联系

  • Replication Framework

接下来的配置就是复制 所需要的 

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server_id=1
gtid_mode=ON
enforce_gtid_consistency=ON
binlog_checksum=NONE

如果你使用的版本低于8.0.3（8.0.3默认配置可以满足复制要求），那么需要在配置如下选项

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log_bin=binlog
log_slave_updates=ON
binlog_format=ROW
master_info_repository=TABLE
relay_log_info_repository=TABLE
  • Group Replication Settings

接下来的配置，就是组复制所需要的了 

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transaction_write_set_extraction=XXHASH64
group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"
group_replication_start_on_boot=off
group_replication_local_address= "127.0.0.1:24901"
group_replication_group_seeds= "127.0.0.1:24901,127.0.0.1:24902,127.0.0.1:24903"
group_replication_bootstrap_group=off

a) transaction_write_set_extraction=XXHASH64 ： 表示使用XXHASH64算法来编码write set

b) group_replication_group_name=”aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa” ： 告诉插件这个组已经创建了，它的名字是aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa
group_replication_group_name 的值必须是UUID，可以使用select UUID（）来生产

c) group_replication_start_on_boot=off ：表示当server开启的时候，并不自动开启MGR。

d）group_replication_local_address= “127.0.0.1:24901” ： 告诉插件用127.0.0.1：24901进行内部通信，不是用来给业务查询的哦
推荐的端口是：33061 ，教程中是24901，因为是部署在同一台机器上

e）group_replication_group_seeds= “127.0.0.1:24901,127.0.0.1:24902,127.0.0.1:24903”： 这里面列的ip，port是给该组新成员使用的，叫做种子成员。
在performance_schema.replication_group_members能查到
当开启组复制的时候，它是不会使用group_replication_group_seeds选项的，因为该机器是负责引导这个组的
换句话说，任何引导server的数据都是给其他加入成员的server服务的
第二个加入到组成员的server都必须询问，只有组成员列表的成员才能加入，任何缺少的数据都可以问负责引导的成员server获取，随后就加入到了这组group
第三个server可以询问前两个server成员中的任意一个询问、并同步数据
随后的server都是以同样的步骤来加入组 

一个即将加入的成员必须跟种子成员（group_replication_group_seeds）进行通信

f）group_replication_bootstrap_group=off： 说明插件是否进行引导
重要： 这个选项只能使用一次，否则会出现脑裂的可能。当第一个server引导成online后，应该讲其从on变为off

配置这个group的其他server实例跟以上的方法非常相似，需要改变下特殊的选项如（server_id, datadir, group_replication_local_address）

18.2.1.3 User Credentials

MGR需要一个group_replication_recovery的复制通道来完成节点之间的数据恢复以及补偿
所以，这一节主要讲group_replication_recovery

开启server使用这个配置文件： 

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mysql-8.0/bin/mysqld --defaults-file=data/s1/s1.cnf

创建一个mysql用户，具有 REPLICATION-SLAVE 权限
如果你想避免这个grant操作在其他server也发生，可以如下配置 

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mysql> SET SQL_LOG_BIN=0;

相关创建用户的命令： 

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mysql> CREATE USER rpl_user@'%' IDENTIFIED BY 'password';
mysql> GRANT REPLICATION SLAVE ON *.* TO rpl_user@'%';
mysql> FLUSH PRIVILEGES;

如果之前这是了sql-log-bin,那么现在需要恢复原状 

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mysql> SET SQL_LOG_BIN=1;

使用change master命令来配置group_replication_recovery 

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mysql> CHANGE MASTER TO MASTER_USER='rpl_user', MASTER_PASSWORD='password' \\
		      FOR CHANNEL 'group_replication_recovery';

分布式recovery是加入一个组的第一步，用来获取自己没有的事务
如果这个group_replication_recovery通道没有配置正确，那么此server将不能从donar member中获取事务来进行数据同步恢复，因此就加入组失败

18.2.1.4 Launching Group Replication

s1配置正确后，接下来在sever执行如下命令 

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INSTALL PLUGIN group_replication SONAME 'group_replication.so';

重要：在你load MGR前，mysql.session（8.0.2引入）用户必须要存在，如果你的数据字典表是老版本，那么需要mysql_upgrade，否则会报错

There was an error when trying to access the server with user: mysql.session@localhost. Make sure the user is present in the server and that mysql_upgrade was ran after a server update..

可以通过如下命令来检测pugin是否正确 

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mysql> SHOW PLUGINS;
+----------------------------+----------+--------------------+----------------------+-------------+
| Name                       | Status   | Type               | Library              | License     |
+----------------------------+----------+--------------------+----------------------+-------------+
| binlog                     | ACTIVE   | STORAGE ENGINE     | NULL                 | PROPRIETARY |
(...)
| group_replication          | ACTIVE   | GROUP REPLICATION  | group_replication.so | PROPRIETARY |
+----------------------------+----------+--------------------+----------------------+-------------+

开启group，在s1作为引导server，并开启MGR
引导过程，只能在一个server上设置，而且只能一次
这就是为什么配置文件中设置为off的原因 

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SET GLOBAL group_replication_bootstrap_group=ON;
START GROUP_REPLICATION;
SET GLOBAL group_replication_bootstrap_group=OFF;

一旦START GROUP_REPLICATION;成功，这个group就算启动成功了 ， 你可以这样来check 

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mysql> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+-------------+-------------+---------------+
| CHANNEL_NAME              | MEMBER_ID                            | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE  |
+---------------------------+--------------------------------------+-------------+-------------+---------------+
| group_replication_applier | ce9be252-2b71-11e6-b8f4-00212844f856 | myhost      |       24801 | ONLINE        |
+---------------------------+--------------------------------------+-------------+-------------+---------------+

为了论证它确实OK了，可以如下：

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mysql> CREATE DATABASE test;
mysql> USE test;
mysql> CREATE TABLE t1 (c1 INT PRIMARY KEY, c2 TEXT NOT NULL);
mysql> INSERT INTO t1 VALUES (1, 'Luis');
mysql> SELECT * FROM t1;
+----+------+
| c1 | c2   |
+----+------+
|  1 | Luis |
+----+------+
mysql> SHOW BINLOG EVENTS;
+---------------+-----+----------------+-----------+-------------+--------------------------------------------------------------------+
| Log_name      | Pos | Event_type     | Server_id | End_log_pos | Info                                                               |
+---------------+-----+----------------+-----------+-------------+--------------------------------------------------------------------+
| binlog.000001 |   4 | Format_desc    |         1 |         123 | Server ver: 8.0.2-gr080-log, Binlog ver: 4                        |
| binlog.000001 | 123 | Previous_gtids |         1 |         150 |                                                                    |
| binlog.000001 | 150 | Gtid           |         1 |         211 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:1'  |
| binlog.000001 | 211 | Query          |         1 |         270 | BEGIN                                                              |
| binlog.000001 | 270 | View_change    |         1 |         369 | view_id=14724817264259180:1                                        |
| binlog.000001 | 369 | Query          |         1 |         434 | COMMIT                                                             |
| binlog.000001 | 434 | Gtid           |         1 |         495 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:2'  |
| binlog.000001 | 495 | Query          |         1 |         585 | CREATE DATABASE test                                               |
| binlog.000001 | 585 | Gtid           |         1 |         646 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:3'  |
| binlog.000001 | 646 | Query          |         1 |         770 | use `test`; CREATE TABLE t1 (c1 INT PRIMARY KEY, c2 TEXT NOT NULL) |
| binlog.000001 | 770 | Gtid           |         1 |         831 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:4'  |
| binlog.000001 | 831 | Query          |         1 |         899 | BEGIN                                                              |
| binlog.000001 | 899 | Table_map      |         1 |         942 | table_id: 108 (test.t1)                                            |
| binlog.000001 | 942 | Write_rows     |         1 |         984 | table_id: 108 flags: STMT_END_F                                    |
| binlog.000001 | 984 | Xid            |         1 |        1011 | COMMIT /* xid=38 */                                                |
+---------------+-----+----------------+-----------+-------------+--------------------------------------------------------------------+

18.2.1.5 Adding Instances to the Group

现在，group已经有一个成员s1了，也有一些数据在里面。
现在是时候在给这个group扩展之前配置的server了

  • 18.2.1.5.1 Adding a Second Instance 添加第二个实例

为了给这个group添加第二个实例S2，首先要创建一个配置文件
这个配置文件跟s1类似，除了一些位置和目录信息、port、serverid 之外 

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[mysqld]
# server configuration
datadir=<full_path_to_data>/data/s2
basedir=<full_path_to_bin>/mysql-8.0/
port=24802
socket=<full_path_to_sock_dir>/s2.sock
#
# Replication configuration parameters
#
server_id=2
gtid_mode=ON
enforce_gtid_consistency=ON
binlog_checksum=NONE
#
# Group Replication configuration
#
transaction_write_set_extraction=XXHASH64
group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"
group_replication_start_on_boot=off
group_replication_local_address= "127.0.0.1:24902"
group_replication_group_seeds= "127.0.0.1:24901,127.0.0.1:24902,127.0.0.1:24903"
group_replication_bootstrap_group= off

开启server 

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mysql-8.0/bin/mysqld --defaults-file=data/s2/s2.cnf

给group_replication_recovery 配置 recovery credentials 

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SET SQL_LOG_BIN=0;
CREATE USER rpl_user@'%' IDENTIFIED BY 'password';
GRANT REPLICATION SLAVE ON *.* TO rpl_user@'%';
SET SQL_LOG_BIN=1;
CHANGE MASTER TO MASTER_USER='rpl_user', MASTER_PASSWORD='password' \\
	FOR CHANNEL 'group_replication_recovery';

安装MGR 插件 

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mysql> INSTALL PLUGIN group_replication SONAME 'group_replication.so';

将s2加入到group , 跟之前不一样的是：s2不需要设置group_replication_bootstrap_group=on了，因为s1已经引导过一次了 

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mysql> START GROUP_REPLICATION;

检测MGR是否加入了s2 

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mysql> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+-------------+-------------+---------------+
| CHANNEL_NAME              | MEMBER_ID                            | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE  |
+---------------------------+--------------------------------------+-------------+-------------+---------------+
| group_replication_applier | 395409e1-6dfa-11e6-970b-00212844f856 | myhost      |       24801 | ONLINE        |
| group_replication_applier | ac39f1e6-6dfa-11e6-a69d-00212844f856 | myhost      |       24802 | ONLINE        |
+---------------------------+--------------------------------------+-------------+-------------+---------------+

如果s2标记为online，那么它必须要跟s1的数据自动保持一致。 请如下确认下 

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mysql> SHOW DATABASES LIKE 'test';
+-----------------+
| Database (test) |
+-----------------+
| test            |
+-----------------+
mysql> SELECT * FROM test.t1;
+----+------+
| c1 | c2   |
+----+------+
|  1 | Luis |
+----+------+
mysql> SHOW BINLOG EVENTS;
+---------------+------+----------------+-----------+-------------+--------------------------------------------------------------------+
| Log_name      | Pos  | Event_type     | Server_id | End_log_pos | Info                                                               |
+---------------+------+----------------+-----------+-------------+--------------------------------------------------------------------+
| binlog.000001 |    4 | Format_desc    |         2 |         123 | Server ver: 8.0.3-log, Binlog ver: 4                              |
| binlog.000001 |  123 | Previous_gtids |         2 |         150 |                                                                    |
| binlog.000001 |  150 | Gtid           |         1 |         211 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:1'  |
| binlog.000001 |  211 | Query          |         1 |         270 | BEGIN                                                              |
| binlog.000001 |  270 | View_change    |         1 |         369 | view_id=14724832985483517:1                                        |
| binlog.000001 |  369 | Query          |         1 |         434 | COMMIT                                                             |
| binlog.000001 |  434 | Gtid           |         1 |         495 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:2'  |
| binlog.000001 |  495 | Query          |         1 |         585 | CREATE DATABASE test                                               |
| binlog.000001 |  585 | Gtid           |         1 |         646 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:3'  |
| binlog.000001 |  646 | Query          |         1 |         770 | use `test`; CREATE TABLE t1 (c1 INT PRIMARY KEY, c2 TEXT NOT NULL) |
| binlog.000001 |  770 | Gtid           |         1 |         831 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:4'  |
| binlog.000001 |  831 | Query          |         1 |         890 | BEGIN                                                              |
| binlog.000001 |  890 | Table_map      |         1 |         933 | table_id: 108 (test.t1)                                            |
| binlog.000001 |  933 | Write_rows     |         1 |         975 | table_id: 108 flags: STMT_END_F                                    |
| binlog.000001 |  975 | Xid            |         1 |        1002 | COMMIT /* xid=30 */                                                |
| binlog.000001 | 1002 | Gtid           |         1 |        1063 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:5'  |
| binlog.000001 | 1063 | Query          |         1 |        1122 | BEGIN                                                              |
| binlog.000001 | 1122 | View_change    |         1 |        1261 | view_id=14724832985483517:2                                        |
| binlog.000001 | 1261 | Query          |         1 |        1326 | COMMIT                                                             |
+---------------+------+----------------+-----------+-------------+--------------------------------------------------------------------+

如果s2的数据和s1的数据一样，那么说明s2真的加入成功了

  • 18.2.1.5.2 Adding Additional Instances 添加其他的实例

添加第三个和其他的server加入到group的步骤跟添加s2是一模一样的，除了一些变量之外
下面罗列下步骤

1） Create the configuration file 

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[mysqld]
# server configuration
datadir=<full_path_to_data>/data/s3
basedir=<full_path_to_bin>/mysql-8.0/
port=24803
socket=<full_path_to_sock_dir>/s3.sock
#
# Replication configuration parameters
#
server_id=3
gtid_mode=ON
enforce_gtid_consistency=ON
binlog_checksum=NONE
#
# Group Replication configuration
#
group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"
group_replication_start_on_boot=off
group_replication_local_address= "127.0.0.1:24903"
group_replication_group_seeds= "127.0.0.1:24901,127.0.0.1:24902,127.0.0.1:24903"
group_replication_bootstrap_group= off

2) Start the server 

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mysql-8.0/bin/mysqld --defaults-file=data/s3/s3.cnf

3) Configure the recovery credentials for the group_replication_recovery channel. 

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SET SQL_LOG_BIN=0;
CREATE USER rpl_user@'%' IDENTIFIED BY 'password';
GRANT REPLICATION SLAVE ON *.* TO rpl_user@'%';
FLUSH PRIVILEGES;
SET SQL_LOG_BIN=1;
CHANGE MASTER TO MASTER_USER='rpl_user', MASTER_PASSWORD='password'  \\
FOR CHANNEL 'group_replication_recovery';

4) Install the Group Replication plugin and start it. 

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INSTALL PLUGIN group_replication SONAME 'group_replication.so';
START GROUP_REPLICATION;

5) 检查 

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mysql> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+-------------+-------------+---------------+
| CHANNEL_NAME              | MEMBER_ID                            | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE  |
+---------------------------+--------------------------------------+-------------+-------------+---------------+
| group_replication_applier | 395409e1-6dfa-11e6-970b-00212844f856 | myhost      |       24801 | ONLINE        |
| group_replication_applier | 7eb217ff-6df3-11e6-966c-00212844f856 | myhost      |       24803 | ONLINE        |
| group_replication_applier | ac39f1e6-6dfa-11e6-a69d-00212844f856 | myhost      |       24802 | ONLINE        |
+---------------------------+--------------------------------------+-------------+-------------+---------------+

6) 确认数据是否ok 

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mysql> SHOW DATABASES LIKE 'test';
+-----------------+
| Database (test) |
+-----------------+
| test            |
+-----------------+
mysql> SELECT * FROM test.t1;
+----+------+
| c1 | c2   |
+----+------+
|  1 | Luis |
+----+------+
mysql> SHOW BINLOG EVENTS;
+---------------+------+----------------+-----------+-------------+--------------------------------------------------------------------+
| Log_name      | Pos  | Event_type     | Server_id | End_log_pos | Info                                                               |
+---------------+------+----------------+-----------+-------------+--------------------------------------------------------------------+
| binlog.000001 |    4 | Format_desc    |         3 |         123 | Server ver: 8.0.3-log, Binlog ver: 4                              |
| binlog.000001 |  123 | Previous_gtids |         3 |         150 |                                                                    |
| binlog.000001 |  150 | Gtid           |         1 |         211 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:1'  |
| binlog.000001 |  211 | Query          |         1 |         270 | BEGIN                                                              |
| binlog.000001 |  270 | View_change    |         1 |         369 | view_id=14724832985483517:1                                        |
| binlog.000001 |  369 | Query          |         1 |         434 | COMMIT                                                             |
| binlog.000001 |  434 | Gtid           |         1 |         495 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:2'  |
| binlog.000001 |  495 | Query          |         1 |         585 | CREATE DATABASE test                                               |
| binlog.000001 |  585 | Gtid           |         1 |         646 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:3'  |
| binlog.000001 |  646 | Query          |         1 |         770 | use `test`; CREATE TABLE t1 (c1 INT PRIMARY KEY, c2 TEXT NOT NULL) |
| binlog.000001 |  770 | Gtid           |         1 |         831 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:4'  |
| binlog.000001 |  831 | Query          |         1 |         890 | BEGIN                                                              |
| binlog.000001 |  890 | Table_map      |         1 |         933 | table_id: 108 (test.t1)                                            |
| binlog.000001 |  933 | Write_rows     |         1 |         975 | table_id: 108 flags: STMT_END_F                                    |
| binlog.000001 |  975 | Xid            |         1 |        1002 | COMMIT /* xid=29 */                                                |
| binlog.000001 | 1002 | Gtid           |         1 |        1063 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:5'  |
| binlog.000001 | 1063 | Query          |         1 |        1122 | BEGIN                                                              |
| binlog.000001 | 1122 | View_change    |         1 |        1261 | view_id=14724832985483517:2                                        |
| binlog.000001 | 1261 | Query          |         1 |        1326 | COMMIT                                                             |
| binlog.000001 | 1326 | Gtid           |         1 |        1387 | SET @@SESSION.GTID_NEXT= 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:6'  |
| binlog.000001 | 1387 | Query          |         1 |        1446 | BEGIN                                                              |
| binlog.000001 | 1446 | View_change    |         1 |        1585 | view_id=14724832985483517:3                                        |
| binlog.000001 | 1585 | Query          |         1 |        1650 | COMMIT                                                             |
+---------------+------+----------------+-----------+-------------+--------------------------------------------------------------------+
Contents
  1. 1. 18.2.1 Deploying Group Replication in Single-Primary Mode
    1. 1.1. 18.2.1.1 Deploying Instances for Group Replication
    2. 1.2. 18.2.1.2 Configuring an Instance for Group Replication
    3. 1.3. 18.2.1.3 User Credentials
    4. 1.4. 18.2.1.4 Launching Group Replication
    5. 1.5. 18.2.1.5 Adding Instances to the Group

幸福,不在于得到的多

而在于计较的少