一、什么是GTID?
GTID(Global Transaction Identifiers)是全局事务标识
当使用GTIDS时,在主上提交的每一个事务都会被识别和跟踪,并且运用到所有从MySQL,而且配置主从或者主从切换时不再需要指定 master_log_files和master_log_pos;由于GTID-base复制是完全基于事务的,所以能很简单的决定主从复制的一致性;官方建议Binlog采用Row格式
二、GTID的表示方式
source_id:transaction_id
source_id:表示执行事务的主库的UUID(server_uuid:Mysql5.6的data目录下启动时会生成auto.cnf文件记录了uuid,重启后uuid不变,删除文件后会重新生成新的uuid);
transaction_id:是一个从1开始自增的计数,表示在这个主库上执行的第n个事务;
由于每台Mysql的uuid是全球唯一的,transaction_id自身唯一,就保证了GTID全局唯一性
| mysql> show variables like 'server_uuid'; +---------------+--------------------------------------+ | Variable_name | Value | +---------------+--------------------------------------+ | server_uuid | 4468c0e8-ef6f-11e3-9c2c-0200c0a80ad8 | +---------------+--------------------------------------+ 1 row in set (0.00 sec) |
三、基于GTID的复制配置
master:192.168.10.216
slave :192.168.10.217
步骤:
修改主从my.cnf增加GTID支持—>主只读—>拷贝数据到从数据目录—>重启主从—>在从上进行配置
1.修改主从my.cnf增加GTID支持
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|
主Mysql配置:
server-id=216
binlog-format=ROW
gtid-mode=on
enforce-gtid-consistency=true
log-bin=mysql-bin
log-slave-updates=true
slave更新是否记入日志
从Mysql配置:
server-id=217
同一个复制拓扑中的所有服务器的id号必须惟一
binlog-format=ROW
gtid-mode=on 启用gtid类型,否则就是普通的复制架构
enforce-gtid-consistency=true
强制GTID的一致性
log-bin=mysql-bin
log-slave-updates=true
slave更新是否记入日志
只从库配置:
slave-paralles-workers
设定从服务器的SQL线程数;0表示关闭多线程复制功能;
|
2.主只读
| mysql> SET @@global.read_only = ON; |
拷贝主数据到从目录
3.重启主从Mysql
4.在从上配置基于GTID的复制
|
mysql>
CHANGE
MASTER
TO
>
MASTER_HOST
=
‘192.168.10.216’,
>
MASTER_PORT
=
3306,
>
MASTER_USER
=
'rep',
>
MASTER_PASSWORD
=
'geekwolf',
>
MASTER_AUTO_POSITION
=
1;
|
5.启动从库
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 | mysql> start slave; Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> show slave status \G *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 192.168.10.216 Master_User: rep Master_Port: 3306 Connect_Retry: 60 Master_Log_File: mysql-bin.000002 Read_Master_Log_Pos: 41921904 Relay_Log_File: relay-bin.000002 Relay_Log_Pos: 64520 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: mysql.% Last_Errno: 0 Last_Error: Skip_Counter: 0 Exec_Master_Log_Pos: 41921904 Relay_Log_Space: 64718 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: 216 Master_UUID: 21ad8db5-f038-11e3-a14a-0200c0a80ad8 Master_Info_File: /usr/local/mysql/data/master.info SQL_Delay: 0 SQL_Remaining_Delay: NULL Slave_SQL_Running_State: Reading event from the relay log Master_Retry_Count: 86400 Master_Bind: Last_IO_Error_Timestamp: Last_SQL_Error_Timestamp: Master_SSL_Crl: Master_SSL_Crlpath: Retrieved_Gtid_Set: 21ad8db5-f038-11e3-a14a-0200c0a80ad8:76793-77026 Executed_Gtid_Set: 21ad8db5-f038-11e3-a14a-0200c0a80ad8:1-77025 Auto_Position: 1 1 row in set (0.00 sec) |
注:
两个Yes代表复制正常
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
基于GTID复制的新特性:
Retrieved_Gtid_Set: 21ad8db5-f038-11e3-a14a-0200c0a80ad8:76793-77026
Executed_Gtid_Set: 21ad8db5-f038-11e3-a14a-0200c0a80ad8:1-77025
Retrieved_Gtid_Set项:记录了relay日志从Master获取了binlog日志的位置
Executed_Gtid_Set项:记录本机执行的binlog日志位置(如果是从机,包括Master的binlog日志位置和slave本身的binlog日志位置)
四、基于GTID复制增加新的slave
备份主MySQL数据,记录主gtid_executed—>将备份数据恢复到从数据目录—>设置从gtid_purged的值为主的gtid_executed值—>启动复制即可
1.使用mysqldump备份主数据
mysqldump —all-databases —single-transaction —triggers —routines —host=127.0.0.1 —port=3306 —user=root —password=geekwolf > backup.sql
亦可以使用xtrabackup也支持GTID:
请参考:http://www.mysqlperformanceblog.com/2013/05/09/how-to-create-a-new-or-repair-a-broken-gtid-based-slave-with-percona-xtrabackup/
2.传到从MySQL,恢复数据
由于新版本msqldump会记录并设置GTID_PURGED的值等于主的GTID_EXECUTED,所以只需要将sql导入到从库即可
3.启动主从复制
|
从库执行
mysql
>
CHANGE
MASTER
TO
MASTER_HOST='127.0.0.1',
MASTER_USER='root',
MASTER_PASSWORD=geekwolf',
MASTER_PORT=3306,
MASTER_AUTO_POSITION
=
1;
mysql
>
START
SLAVE;
|
五、基于GTID复制出错的解决办法
问题:
| Slave_IO_Running: No Slave_SQL_Running: Yes Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: 'The slave is connecting using CHANGE MASTER TO MASTER_AUTO_POSITION = 1, but the master has purged binary logs containing GTIDs that the slave requires.' |
解决思路:
从复制跳过已经丢失的binlog,继续复制或者重新做主从(可以参考上面的操作)
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主MySQL:
mysql>
show
global
variables
like
'%gtid_executed%';
+---------------+-----------------------------------------------+
|
Variable_name
|
Value
|
+---------------+-----------------------------------------------+
|
gtid_executed
|
21ad8db5-f038-11e3-a14a-0200c0a80ad8:1-223937
|
+---------------+-----------------------------------------------+
1
row
in
set
(0.00
sec)
从MySQL:
mysql>
set
global
GTID_PURGED="21ad8db5-f038-11e3-a14a-0200c0a80ad8:1-223937";
ERROR
1840
(HY000):
@@GLOBAL.GTID_PURGED
can
only
be
set
when
@@GLOBAL.GTID_EXECUTED
is
empty.
mysql>
reset
master;
Query
OK,
0
rows
affected
(0.19
sec)
mysql>
show
global
variables
like
'GTID_EXECUTED';
+---------------+-----------------------------------------------+
|
Variable_name
|
Value
|
+---------------+-----------------------------------------------+
|
gtid_executed
| |
+---------------+-----------------------------------------------+
1
row
in
set
(0.00
sec)
mysql>
stop
slave;
Query
OK,
0
rows
affected,
1
warning
(0.00
sec)
mysql>
set
global
GTID_PURGED="21ad8db5-f038-11e3-a14a-0200c0a80ad8:1-223937";
Query
OK,
0
rows
affected
(0.13
sec)
mysql>
start
slave;
Query
OK,
0
rows
affected
(0.04
sec)
mysql>
show
slave
status\G
[...]
Slave_IO_Running:
Yes
Slave_SQL_Running:
Yes
[...]
|
注意事项:
使用基于GTID复制时,不需要再关心master_log_file和master_log_pos,替代的是只需要知道master上的GTID,并且配置在从上即可;
记录GTID的有两个全局变量:gtid_executed和gtid_purged
与GTID复制相关的参数:
GTID_EXECUTED :表示已经在该实例上执行过的事务;执行RESET MASTER可以置空该参数;也可以设置GTID_NEXT执行一个空事务来影响GTID_EXECUTED
GTID_NEXT :是SESSION级别参数,表示下一个事务被执行使用的GTID(show variables like ‘gtid_%’;)
GTID_PURGED :表示被删除的binlog事务GTID,它是GTID_EXCUTED的子集,MySQL5.6.9,该参数无法被设置
GTID_OWENED :表示正在执行的事务的GTID以及对应的线程ID
如果设置MASTER_AUTO_POSITION = 1表示主从复制连接使用基于GTID的方式复制
| CHANGE MASTER TO MASTER_HOST='192.168.10.216',MASTER_USER='rep',MASTER_PASSWORD='geekwolf',MASTER_AUTO_POSITION=1; |
如果在GTID复制模式下想要使用基于文件的复制协议需要MASTER_AUTO_POSITION=0(至少指定其中MASTER_LOG_FILE、MASTER_LOG_POSITION一个)
|
CHANGE
MASTER
TO
MASTER_HOST='192.168.10.216',MASTER_USER='rep',MASTER_PASSWORD='geekwolf',MASTER_LOG_FILE='mysql-bin.000002',MASTER_LOG_POS=120,MASTER_AUTO_POSITION=0;
|
参考文档:
MYSQL 5.6 GTID-based Replication
MYSQL 5.6 GTID模式下手工删除日志导致备库数据丢失
How
to create a new (or repair a broken) GTID based slave with Percona XtraBackup