MySql GTID主从复制
目录
1.GTID介绍
1.1GTID是什么
1.2 GTID Replication介绍
1.3 GTID的组成
1.4 GTID的作用
1.5 为什么要用GTID
1.6 GTID比传统复制的优势
1.7GTID复制实现的工作原理
2 主从复制
2.1 一主一从
2.1.1部署数据库可查看 2.1.2 授权一个用户，用于主从复制主从>
2.1.3 修改master主配文件
2.1.4 slave主配文件
2.1.5 配置slave主机，授权从数据库
2.1.6 验证主从复制
2.2 一主多从
2.2.1 第二台从数据库slave主配文件
2.2.2 配置第二台slave主机
2.3 多主一从
2.3.1 两台主数据库配置和上述主数据库相同，从数据库配置也相同2.3.2 查看主库信息
2.3.3 配置slave主机
2.3.4 在从库上配置主库信息
2.3.5 验证测试
1.GTID介绍
1.1GTID是什么
GTID(Global Transaction ID)是对于一个已提交事务的编号，并且是一个全局唯一的编号。GTID实际上是由UUID+TID组成的。其中UUID是一个MySQL实例的唯一标识，保存在mysql数据目录下的auto.cnf文件里。TID代表了该实例上已经提交的事务数量，并且随着事务提交单调递增。下面是一个GTID的具体形式：3E11FA47-71CA-11E1-9E33-C80AA9429562:23。
全称为: Global Transaction ID ,可简化MySQL(5.6版本之后)的主从切换以及Failover。
GTID是一个字符串类似 `3E11FA47-71CA-11E1-9E33-C80AA9429562:23`
由UUID+TID组成，
UUID代表MySQL实例，
TID代表这个实例提交的事务数量。
1.2 GTID Replication介绍
从MySQL5.6开始增加了强大的GTID（Global Transaction ID，全局事务ID）这个特性，用来强化数据库的主备一致性， 故障恢复， 以及容错能力。用于取代过去传统的主从复制（即：基于binlog和position的异步复制）。借助GTID，在发生主备切换的情况下，MySQL的其他slave可以自动在新主上找到正确的复制位置，这大大简化了复杂复制拓扑下集群的维护，也减少了人为设置复制position发生误操作的风险。另外，基于GTID的复制可以忽略已经执行过的事务，减少了数据发生不一致的风险。
1.3 GTID的组成
GTID是由server_uuid和事务id组成的，即GTID=server_uuid:transaction_id。
server_uuid，是在MySQL第一次启动时自动生成并持久化到auto.cnf文件（存放在数据目录下，每台机器的server_uuid都不一样。
transaction_id，是一个从1开始的自增计数，表示在这个主库上执行的第n个事务。MySQL会保证事务与GTID之间的1:1映射，如：6ba9a76d-606b-11ea-b3ce-000c29cb3421:1
表示在以6ba9a76d-606b-11ea-b3ce-000c29cb3421为唯一标识的MySQL实例上执行的第1个数据库事务。
一组连续的事务可以用 “-” 连接的事务序号范围表示。例如：6ba9a76d-606b-11ea-b3ce-000c29cb3421:1-15
1.4 GTID的作用
根据GTID可以知道事务最初是在哪个实例上提交的
GTID的存在方便了Replication的Failover
1.5 为什么要用GTID
在主从复制中，尤其是半同步复制中， 由于Master 的dump进程一边要发送binlog给Slave，一边要等待Slave的ACK消息，这个过程是串行的，即前一个事物的ACK没有收到消息，那么后一个事物只能排队候着； 这样将会极大地影响性能；有了GTID后，SLAVE就直接可以通过数据流获得GTID信息，而且可以同步
主从故障切换中，如果一台MASTER down，需要提取拥有最新日志的SLAVE做MASTER，这个是很好判断，而有了GTID，就只要以GTID为准即可方便判断；而有了GTID后，SLAVE就不需要一直保存这bin-log 的文件名和Position了；只要启用MASTER_AUTO_POSITION 即可
当MASTER crash的时候，GTID有助于保证数据一致性，因为每个事物都对应唯一GTID，如果在恢复的时候某事物被重复提交，SLAVE会直接忽略
1.6 GTID比传统复制的优势
更简单的实现failover，不用以前那样在需要找log_file和log_Pos
更简单的搭建主从复制
比传统复制更加安全
GTID是连续没有空洞的，因此主从库出现数据冲突时，可以用添加空事物的方式进行跳过
1.7GTID复制实现的工作原理
主节点更新数据时，会在事务前产生GTID，一起记录到binlog日志中
从节点的I/O线程将变更的bin log，写入到本地的relay log中
SQL线程从relay log中获取GTID，然后对比本地binlog是否有记录（所以MySQL从节点必须要开启binary log）
如果有记录，说明该GTID的事务已经执行，从节点会忽略
如果没有记录，从节点就会从relay log中执行该GTID的事务，并记录到bin log
在解析过程中会判断是否有主键，如果没有就用二级索引，如果有就用全部扫描
2 主从复制
2.1 一主一从
| 数据库 | IP |
| master | 192.268.25.140 |
| slave | 192.168.25.142 |
2.1.1部署数据库可查看
2.1.2 授权一个用户，用于主从复制
2.1.2 授权一个用户，用于主从复制
mysql> show variables like '%gtid%';
+----------------------------------+-----------+
| Variable_name | Value |
+----------------------------------+-----------+
| binlog_gtid_simple_recovery | ON |
| enforce_gtid_consistency | OFF |
| gtid_executed_compression_period | 1000 |
| gtid_mode | OFF |
| gtid_next | AUTOMATIC |
| gtid_owned | |
| gtid_purged | |
| session_track_gtids | OFF |
+----------------------------------+-----------+
8 rows in set (0.01 sec)
mysql> create user 'zj'@'192.168.25.142' identified by "1";
Query OK, 0 rows affected (0.01 sec)
mysql> grant replication slave on *.* to 'zj'@'192.168.25.142' ;
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
2.1.3 修改master主配文件
[root@localhost ~]# vim /etc/my.cnf
[mysqld]
basedir = /usr/local/mysql
datadir = /opt/data
socket = /tmp/mysql.sock
port = 3306
pid-file = /opt/data/mysql.pid
skip-name-resolve
log-bin = mysql-bin #开启二进制日志
server-id = 1
gtid-mode = on #开启gtid模式
enforce-gtid-consistency = on #强制gtid一致性，开启后对特定的create table不被支持
binlog-format = row #默认为mixed混合模式，更改成row复制，为了数据一致性
log-slave-updates = 1 #从库binlog才会记录主库同步的操作日志
skip-slave-start = 1 #跳过slave复制线程
// 重启数据库服务
[root@localhost ~]# service mysqld restart
Shutting down MySQL.. SUCCESS!
Starting MySQL. SUCCESS!
// 查看master数据库状态
mysql> show master status;
+------------------+----------+--------------+------------------+------------------------------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+------------------------------------------+
| mysql-bin.000014 | 1951 | | | b736875b-097e-11ec-b557-000c29810dc2:1-9 |
+------------------+----------+--------------+------------------+------------------------------------------+
1 row in set (0.00 sec)
2.1.4 slave主配文件
[root@localhost ~]# vim /etc/my.cnf
[mysqld]
basedir = /usr/local/mysql
datadir = /opt/data
socket = /tmp/mysql.sock
port = 3306
pid-file = /opt/data/mysql.pid
skip-name-resolve
server-id = 2
log-bin = mysql-bin
binlog-format = row
skip-slave-start = 1
log-slave-updates = 1
gtid-mode = on
enforce-gtid-consistency = on
[root@localhost ~]# service mysqld restart
Shutting down MySQL.. SUCCESS!
Starting MySQL. SUCCESS!
2.1.5 配置slave主机，授权从数据库
// 检查gtid模式状态
mysql> show variables like '%gtid%';
+----------------------------------+-----------+
| Variable_name | Value |
+----------------------------------+-----------+
| binlog_gtid_simple_recovery | ON |
| enforce_gtid_consistency | ON |
| gtid_executed_compression_period | 1000 |
| gtid_mode | ON |
| gtid_next | AUTOMATIC |
| gtid_owned | |
| gtid_purged | |
| session_track_gtids | OFF |
+----------------------------------+-----------+
mysql> reset slave;
Query OK, 0 rows affected (0.01 sec)
mysql> change master to
-> master_host='192.168.25.140' ,
-> master_user='zj' ,
-> master_password='1' ,
-> master_auto_position=1;
Query OK, 0 rows affected, 2 warnings (0.01 sec)
mysql> start slave ;
Query OK, 0 rows affected (0.00 sec)
mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.25.140
Master_User: zj
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000014
Read_Master_Log_Pos: 154
Relay_Log_File: localhost-relay-bin.000003
Relay_Log_Pos: 367
Relay_Master_Log_File: mysql-bin.000014
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
2.1.6 验证主从复制
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| JJ |
| mysql |
| performance_schema |
| sys |
+--------------------+
5 rows in set (0.00 sec)
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------------------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------------------------------+
| mysql_bin.000006 | 1389 | | | b736875b-097e-11ec-b557-000c29810dc2:1-10 |
+------------------+----------+--------------+------------------+-------------------------------------------+
1 row in set (0.00 sec)
2.2 一主多从
| 数据库 | IP |
| master | 192.168.25.1403 |
| slave | 192.168.25.142 |
| slave | 192.268.25.144 |
2.2.1 第二台从数据库slave主配文件
[root@localhost ~]# vim /etc/my.cnf
[mysqld]
basedir = /usr/local/mysql
datadir = /opt/data
socket = /tmp/mysql.sock
port = 3306
pid-file = /opt/data/mysql.pid
skip-name-resolve
server-id = 3 //第三台从服务器id 不能与前面使用过的一样
log-bin = mysql-bin
binlog-format = row
skip-slave-start = 1
log-slave-updates = 1
gtid-mode = on
enforce-gtid-consistency = on
[root@localhost ~]# service mysqld restart
Shutting down MySQL.. SUCCESS!
Starting MySQL. SUCCESS
2.2.2 配置第二台slave主机
mysql> show variables like '%gtid%';
+----------------------------------+-----------+
| Variable_name | Value |
+----------------------------------+-----------+
| binlog_gtid_simple_recovery | ON |
| enforce_gtid_consistency | ON |
| gtid_executed_compression_period | 1000 |
| gtid_mode | ON |
| gtid_next | AUTOMATIC |
| gtid_owned | |
| gtid_purged | |
| session_track_gtids | OFF |
+----------------------------------+-----------+
mysql> reset slave;
Query OK, 0 rows affected (0.01 sec)
mysql> change master to
-> master_host='192.168.25.140' ,
-> master_user='zj' ,
-> master_password='1' ,
-> master_auto_position=1;
Query OK, 0 rows affected, 2 warnings (0.01 sec)
mysql> start slave ;
Query OK, 0 rows affected (0.00 sec)
mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.25.140
Master_User: zj
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000014
Read_Master_Log_Pos: 1776
Relay_Log_File: localhost-relay-bin.000004
Relay_Log_Pos: 454
Relay_Master_Log_File: mysql-bin.000014
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| JJ |
| mysql |
| performance_schema |
| sys |
+--------------------+
5 rows in set (0.00 sec)
mysql> show master status;
+------------------+----------+--------------+------------------+---------------------------------------------------------------------------------------------------------------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+---------------------------------------------------------------------------------------------------------------------------+
| mysql_bin.000008 | 750 | | | b736875b-097e-11ec-b557-000c29810dc2:1-10,
ba11a7ff-097f-11ec-9272-000c29959565:1,
ddd6f885-0a26-11ec-81cc-000c29f2278e:1 |
+------------------+----------+--------------+------------------+---------------------------------------------------------------------------------------------------------------------------+
2.3 多主一从
| 数据库 | IP |
| master | 192.168.25.140 |
| master | 192.168.25.142 |
| slave | 192.168.25.144 |
2.3.1 两台主数据库配置和上述主数据库相同，从数据库配置也相同
2.3.2 查看主库信息
//主库1
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------------------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------------------------------+
| mysql-bin.000014 | 2128 | | | b736875b-097e-11ec-b557-000c29810dc2:1-10 |
+------------------+----------+--------------+------------------+-------------------------------------------+
1 row in set (0.00 sec)
主库2
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------------------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------------------------------+
| mysql-bin.000002 | 154 | | | b736875b-097e-11ec-b557-000c29810dc2:1-10 |
+------------------+----------+--------------+------------------+-------------------------------------------+
1 row in set (0.00 sec)
2.3.3 配置slave主机
//检查gtid模式状态
mysql> show variables like '%gtid%';
+----------------------------------+-----------+
| Variable_name | Value |
+----------------------------------+-----------+
| binlog_gtid_simple_recovery | ON |
| enforce_gtid_consistency | ON |
| gtid_executed_compression_period | 1000 |
| gtid_mode | ON |
| gtid_next | AUTOMATIC |
| gtid_owned | |
| gtid_purged | |
| session_track_gtids | OFF |
+----------------------------------+-----------+
mysql> reset slave;
Query OK, 0 rows affected (0.01 sec)
2.3.4 在从库上配置主库信息
//配置主库1
//下面两条命令不执行，后续会报错
mysql> set global master_info_repository='table';
Query OK, 0 rows affected (0.00 sec)
mysql> set global relay_log_info_repository='table';
Query OK, 0 rows affected (0.00 sec)
mysql> change master to
-> master_host='192.168.25.140' , //这里是主库IP
-> master_user='zj' ,
-> master_password='1' ,
-> master_log_file='mysql-bin.000014'
-> master_log_pos=2128
-> for channel 'master-1'; //创建隧道
配置主库2
mysql> change master to
-> master_host='192.168.25.142' ,
-> master_user='zj' ,
-> master_password='1' ,
-> master_log_file='mysql-bin.000002'
-> master_log_pos=154
-> for channel 'master-2'; //创建隧道
mysql> START SLAVE;
Query OK, 0 rows affected (0.00 sec)
//查看发现都已经开启
mysql> SHOW SLAVE STATUS\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.25.140
Master_User: zj
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000014
Read_Master_Log_Pos: 2128
Relay_Log_File: [email protected]
Relay_Log_Pos: 320
Relay_Master_Log_File: mysql-bin.000014
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 2128
Relay_Log_Space: 544
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 1
Master_UUID: b736875b-097e-11ec-b557-000c29810dc2
Master_Info_File: mysql.slave_master_info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set: baf6e1ae-0a32-11ec-bf3d-000c29f2278e:1
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name: master-1
Master_TLS_Version:
*************************** 2. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.25.142
Master_User: zj
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000002
Read_Master_Log_Pos: 154
Relay_Log_File: [email protected]
Relay_Log_Pos: 320
Relay_Master_Log_File: mysql-bin.000002
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 154
Relay_Log_Space: 544
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 2
Master_UUID: ba11a7ff-097f-11ec-9272-000c29959565
Master_Info_File: mysql.slave_master_info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set: baf6e1ae-0a32-11ec-bf3d-000c29f2278e:1
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name: master-2
Master_TLS_Version:
2 rows in set (0.00 sec)
2.3.5 验证测试
主库1上创建数据库ll
mysql> create database ll;
Query OK, 1 row affected (0.00 sec)
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| ll |
| mysql |
| performance_schema |
| sys |
+--------------------+
5 rows in set (0.00 sec)
主库2上创建数据库mm
mysql> create database mm;
Query OK, 1 row affected (0.00 sec)
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| mm |
+--------------------+
5 rows in set (0.00 sec)
// 从库上开启从服务后查看
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| ll |
| mysql |
| performance_schema |
| sys |
| mm |
+--------------------+
6 rows in set (0.00 sec)