时间：2021-07-01 10:21:17 帮助过：14人阅读
MySQL GTID是在传统的mysql主从复制的基础之上演化而来的产物，即通过UUID加上事务ID的方式来确保每一个事物的唯一性。这样的操作方式使得我们不再需要关心所谓的log_file和log_Pos，只是简单的告诉从库，从哪个服务器上去找主库就OK了。简化了主从的搭建以及failover的过程，同时比传统的复制更加安全可靠。由于GTID是连续没有空洞的，因此主从库出现数据冲突时，可以通过注入空事物的方式进行跳过。本文主要讲述GTID主从架构的错误处理方式。
配置MySQL GTID 主从复制
基于mysqldump搭建gtid主从
很多无法预料的情形导致mysql主从发生事务冲突，主从失败或停止的情形，即需要修复主从
对于GTID方式的主从架构而言，更多的是处理事务冲突来修复主从
GTID不支持通过传统设置sql_slave_skip_counter方法来跳过事务
方法：通过注入空事务来填补事务空洞，等同于传统复制的(set global sql_slave_skip_counter = 1)
步骤：
stop slave；
set gtid_next='xxxxxxx:N'; --指定下一个事务执行的版本，即想要跳过的GTID
begin;
commit; --注入一个空事物
set gtid_next='AUTOMATIC' --自动的寻找GTID事务。
start slave; --开始同步 1、主库新增记录，从库提示主键冲突
2、主库对象可更新，从库无对应的对象可更新
3、主库对象可删除，从库无对应的对象可删除
4、通过延迟从修复主库意外删除的对象
5、主库日志被purged的情形当前演示的主从架构图 # mysqlrplshow --master=root:pass@192.168.1.233:3306 --discover-slaves-login=root:pass --verboseWARNING: Using a password on the command line interface can be insecure. # master on 192.168.1.233: ... connected. # Finding slaves for master: 192.168.1.233:3306 # Replication Topology Graph 192.168.1.233:3306 (MASTER) | +--- 192.168.1.245:3306 [IO: Yes, SQL: Yes] - (SLAVE) | +--- 192.168.1.247:3306 [IO: Yes, SQL: Yes] - (SLAVE)(root@192.168.1.233)[tempdb]>show slave hosts;+-----------+---------------+------+-----------+--------------------------------------+| Server_id | Host | Port | Master_id | Slave_UUID | +-----------+---------------+------+-----------+--------------------------------------+| 245 | 192.168.1.245 | 3306 | 233 | 78336cdc-8cfb-11e6-ba9f-000c29328504 || 247 | 192.168.1.247 | 3306 | 233 | 13a26fc1-555a-11e6-b5e0-000c292e1642 | +-----------+---------------+------+-----------+--------------------------------------+--演示的mysql版本 (root@192.168.1.233)[tempdb]>show variables like 'version';+---------------+------------+| Variable_name | Value | +---------------+------------+| version | 5.7.12-log | +---------------+------------+--查看gtid是否开启 (root@192.168.1.233)[tempdb]>show variables like '%gtid_mode%';+---------------+-------+| Variable_name | Value | +---------------+-------+| gtid_mode | ON | +---------------+-------+--主库上面可以看到基于gtid的dump线程，如下 (root@192.168.1.233)[tempdb]>show processlist;+----+------+-----------------------+--------+------------------+------+| Id | User | Host | db | Command | Time | +----+------+-----------------------+--------+------------------+------+| 17 | repl | node245.edq.com:52685 | NULL | Binlog Dump GTID | 2738 | | 18 | repl | node247.edq.com:33516 | NULL | Binlog Dump GTID | 2690 || 24 | root | localhost | tempdb | Query | 0 | +----+------+-----------------------+--------+------------------+------+
(root@Master)[tempdb]>create table t1 (
-> id tinyint not null primary key,ename varchar(20),blog varchar(50));
(root@Master)[tempdb]>insert into t1
-> values(1,'leshami','http://blog.csdn.net/leshami');
(root@Master)[tempdb]>insert into t1
-> values(2,'robin','http://blog.csdn.net/robinson_0612');
(root@Master)[tempdb]>set sql_log_bin=off;
(root@Master)[tempdb]>delete from t1 where ename='robin';
(root@Master)[tempdb]>set sql_log_bin=on;
(root@Master)[tempdb]>insert into t1
-> values(2,'robin','http://blog.csdn.net/robinson_0612');
-- 从库状态报错，提示重复的primary key
(root@Slave)[tempdb]>show slave status \G
*************************** 1. row ***************************Last_Errno: 1062Last_Error: Could not execute Write_rows event on table tempdb.t1; Duplicate entry '2' for key 'PRIMARY',
Error_code: 1062; handler error HA_ERR_FOUND_DUPP_KEY;
the event's master log node233-binlog.000004, end_log_pos 4426
Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-90
Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-89
Auto_Position: 1
-- 如下解决方案，可以通过删除重库的这条记录
(root@Slave)[tempdb]>stop slave;
(root@Slave)[tempdb]>delete from t1 where ename='robin';
(root@Slave)[tempdb]>start slave;
(root@Slave)[tempdb]>show slave status \G
*************************** 1. row ***************************
Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-90
Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-90,
78336cdc-8cfb-11e6-ba9f-000c29328504:1 --这里多了一个GTID，注意这个是从库上执行的，这里的UUID跟IP 245的UUID一致
Auto_Position: 1
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
(root@Slave)[tempdb]>show variables like '%uuid%';
+---------------+--------------------------------------+
| Variable_name | Value |
+---------------+--------------------------------------+
| server_uuid | 78336cdc-8cfb-11e6-ba9f-000c29328504 |
+---------------+--------------------------------------+--首先在从库上删除leshami这条记录
(root@Slave)[tempdb]>delete from t1 where ename='leshami';
--接下来再主库尝试更新leshami这条记录
(root@Master)[tempdb]>update t1 set
-> blog='http://blog.csdn.net/robinson_0612' where ename='leshami';Query OK, 1 row affected (0.02 sec)
Rows matched: 1 Changed: 1 Warnings: 0
-- 查看从库状态
(root@Slave)[tempdb]>show slave status \G*************************** 1. row ***************************Last_SQL_Errno: 1032
Last_SQL_Error: Could not execute Update_rows event on table tempdb.t1; Can't find record in 't1', Error_code: 1032; handler error HA_ERR_KEY_NOT_FOUND; the event's master log node233-binlog.000004, end_log_pos 4769Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-91
Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-90, 78336cdc-8cfb-11e6-ba9f-000c29328504:1-2-- 通过mysqlbinlog在主服务器上寻找报错的binglog日志文件及位置，找到对应的SQL语句，如下所示
-- update中的where后面的部分为更新前的数据，set部分为更新后的数据，因此可以将更新前的数据插入到从库# mysqlbinlog --no-defaults -v -v --base64-output=DECODE-ROWS /data/node233-binlog.000004|grep -A '10' 4769#161009 13:46:34 server id 233 end_log_pos 4769 CRC32 0xb60df74e Update_rows: table id 147 flags: STMT_END_F### UPDATE `tempdb`.`t1`### WHERE### @1=1 /* TINYINT meta=0 nullable=0 is_null=0 */### @2='leshami' /* VARSTRING(20) meta=20 nullable=1 is_null=0 */### @3='http://blog.csdn.net/leshami' /* VARSTRING(50) meta=50 nullable=1 is_null=0 */### SET### @1=1 /* TINYINT meta=0 nullable=0 is_null=0 */### @2='leshami' /* VARSTRING(20) meta=20 nullable=1 is_null=0 */### @3='http://blog.csdn.net/robinson_0612' /* VARSTRING(50) meta=50 nullable=1 is_null=0 */# at 4769#161009 13:46:34 server id 233 end_log_pos 4800 CRC32 0xa9669811 Xid = 1749COMMIT/*!*/;
SET @@SESSION.GTID_NEXT= 'AUTOMATIC' /* added by mysqlbinlog */ /*!*/;
DELIMITER ;# End of log file/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;
(root@Slave)[tempdb]>select * from t1;
+----+-------+------------------------------------+
| id | ename | blog |
+----+-------+------------------------------------+
| 2 | robin | http://www.gxlcms.com/ |
+----+-------+------------------------------------+
(root@Slave)[tempdb]>stop slave sql_thread;
(root@Slave)[tempdb]>insert into t1 values(1,'leshami','http://blog.csdn.net/leshami');
(root@Slave)[tempdb]>start slave sql_thread;
(root@Slave)[tempdb]>show slave status \G*************************** 1. row *************************** Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-91 Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-91, 78336cdc-8cfb-11e6-ba9f-000c29328504:1-3 Auto_Position: 1-- 如果是在主库上删除记录，而从库上找不到对应的记录，则可以直接跳过该事务 -- 下面我们首选在从库上删除一条记录 (root@Slave)[tempdb]>delete from t1 where ename='robin'; -- 接下来在主库上删除该记录 (root@Master)[tempdb]>delete from t1 where ename='robin'; -- 从库端提示无法找到对应的记录 (root@Slave)[tempdb]>show slave status \G*************************** 1. row ***************************Last_SQL_Error: Could not execute Delete_rows event on table tempdb.t1; Can't find record in 't1', Error_code: 1032; handler error HA_ERR_KEY_NOT_FOUND; the event's master log node233-binlog.000004, end_log_pos 5070Last_SQL_Error_Timestamp: 161009 15:08:06 Master_SSL_Crl: Master_SSL_Crlpath: Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-92 Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-91, 78336cdc-8cfb-11e6-ba9f-000c29328504:1-4 Auto_Position: 1 -- 下面通过注入空事务来跳过 (root@Slave)[tempdb]>stop slave sql_thread; (root@Slave)[tempdb]>set gtid_next='1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:92'; (root@Slave)[tempdb]>begin;commit; (root@Slave)[tempdb]>set gtid_next='AUTOMATIC'; (root@Slave)[tempdb]>start slave sql_thread; (root@Slave)[tempdb]>show slave status \G*************************** 1. row *************************** Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-92 Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-92, 78336cdc-8cfb-11e6-ba9f-000c29328504:1-4 Auto_Position: 1 Replicate_Rewrite_DB: Channel_Name: Master_TLS_Version:
-- 主库上面新增表及记录
(root@Master)[tempdb]>create table t2 (id tinyint not null primary key,
-> ename varchar(20),blog varchar(50));(root@Master)[tempdb]>insert into t2
-> values(1,'leshami','http://blog.csdn.net/leshami');(root@Master)[tempdb]>insert into t2
-> values(2,'robin','http://blog.csdn.net/robinson_0612');(root@Master)[tempdb]>select * from t2;
+----+---------+------------------------------------+
| id | ename | blog |
+----+---------+------------------------------------+
| 1 | leshami | http://www.gxlcms.com/ |
| 2 | robin | http://www.gxlcms.com/ |
+----+---------+------------------------------------+
--先将从库配置为延迟从
(root@Slave)[tempdb]>stop slave sql_thread;
Query OK, 0 rows affected (0.01 sec)
(root@Slave)[tempdb]>CHANGE MASTER TO MASTER_DELAY = 300;
Query OK, 0 rows affected (0.00 sec)
(root@Slave)[tempdb]>start slave sql_thread;
Query OK, 0 rows affected (0.02 sec)
(root@Slave)[tempdb]>show slave status \G*************************** 1. row *************************** Slave_IO_Running: Yes Slave_SQL_Running: Yes SQL_Delay: 300 root@Slave)[tempdb]>show slave status \G*************************** 1. row *************************** Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-99 Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-99, 78336cdc-8cfb-11e6-ba9f-000c29328504:1-4 Auto_Position: 1--查看主库上的binglog gtid
(root@Master)[tempdb]>show master status\G*************************** 1. row *************************** File: node233-binlog.000004 Position: 6970 Binlog_Do_DB:
Binlog_Ignore_DB:
Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-99
1 row in set (0.00 sec)
--在主库上truncate t2
(root@Master)[tempdb]>truncate table t2;
Query OK, 0 rows affected (0.03 sec)
--再次查看主库上的binglog gtid，有99变成了100，这个100即是我们需要跳过的ID
(root@Master)[tempdb]>show master status\G*************************** 1. row *************************** File: node233-binlog.000004 Position: 7121 Binlog_Do_DB:
Binlog_Ignore_DB:
Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-100
1 row in set (0.00 sec)
--从库上跳过被意外truncate的事务
(root@Slave)[tempdb]>stop slave sql_thread;
Query OK, 0 rows affected (0.01 sec)
(root@Slave)[tempdb]>set gtid_next='1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:100';
Query OK, 0 rows affected (0.00 sec)
(root@Slave)[tempdb]>begin;commit;
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.01 sec)
(root@Slave)[tempdb]>set gtid_next='AUTOMATIC';
Query OK, 0 rows affected (0.00 sec)
(root@Slave)[tempdb]>start slave sql_thread;
Query OK, 0 rows affected (0.02 sec)
(root@Slave)[tempdb]>show slave status \G*************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: Master Master_User: repl Master_Port: 3306 Connect_Retry: 60 Master_Log_File: node233-binlog.000004 Read_Master_Log_Pos: 7121 Relay_Log_File: node245-relay-bin.000003 Relay_Log_Pos: 2982 Relay_Master_Log_File: node233-binlog.000004 Slave_IO_Running: Yes Slave_SQL_Running: Yes ........................... Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-100 Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-100, 78336cdc-8cfb-11e6-ba9f-000c29328504:1-4 Auto_Position: 1-- 很多时候我们并不知道表何时被truncate，因此可以从binlog日志得到其gtid
-- 如下所示，可以得到这串 SET @@SESSION.GTID_NEXT= '1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:100'
-- 100即为这个truncate对应的gtid的事务号# mysqlbinlog --no-defaults -v -v --base64-output=DECODE-ROWS /data/node233-binlog.000004|grep -i \> "truncate table t2" -A3 -B10 ### @3='http://blog.csdn.net/robinson_0612' /* VARSTRING(50) meta=50 nullable=1 is_null=0 */# at 6939#161009 18:04:58 server id 233 end_log_pos 6970 CRC32 0x71c5121c Xid = 1775COMMIT/*!*/;# at 6970#161009 18:08:42 server id 233 end_log_pos 7035 CRC32 0x00ba9437 GTID last_committed=26 sequence_number=27SET @@SESSION.GTID_NEXT= '1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:100'/*!*/;# at 7035#161009 18:08:42 server id 233 end_log_pos 7121 CRC32 0x5a8b9723 Query thread_id=26 exec_time=0 error_code=0SET TIMESTAMP=1476007722/*!*/;
truncate table t2
/*!*/;
SET @@SESSION.GTID_NEXT= 'AUTOMATIC' /* added by mysqlbinlog */ /*!*/;
DELIMITER ;-- 首先停止从库，模拟从库被意外宕机 (root@Slave)[tempdb]>stop slave; Query OK, 0 rows affected (0.08 sec) --在主库上进行相应的操作 --此时主库上的gtid_purged为空 (root@Master)[tempdb]>show variables like '%gtid_purged%'; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | gtid_purged | | +---------------+-------+ --查看主库binlog (root@Master)[tempdb]>show binary logs; +-----------------------+-----------+ | Log_name | File_size | +-----------------------+-----------+ | node233-binlog.000001 | 1362104 | | node233-binlog.000002 | 1331 | | node233-binlog.000003 | 217 | | node233-binlog.000004 | 7121 | +-----------------------+-----------+ (root@Master)[tempdb]>select * from t1; +----+---------+------------------------------------+ | id | ename | blog | +----+---------+------------------------------------+ | 1 | leshami | http://www.gxlcms.com/ | | 2 | robin | http://www.gxlcms.com/ | +----+---------+------------------------------------+ --从主库删除记录 (root@Master)[tempdb]>delete from t1; --切换日志 (root@Master)[tempdb]>flush logs; --新增记录 (root@Master)[tempdb]>insert into t1 values(1, -> 'xuputi','http://blog.csdn.net/leshami');(root@Master)[tempdb]>show binary logs; +-----------------------+-----------+ | Log_name | File_size | +-----------------------+-----------+ | node233-binlog.000001 | 1362104 | | node233-binlog.000002 | 1331 | | node233-binlog.000003 | 217 | | node233-binlog.000004 | 7513 | | node233-binlog.000005 | 490 | +-----------------------+-----------+ --清理binlog (root@Master)[tempdb]>purge binary logs to 'node233-binlog.000005'; Query OK, 0 rows affected (0.01 sec) (root@Master)[tempdb]>show binary logs; +-----------------------+-----------+ | Log_name | File_size | +-----------------------+-----------+ | node233-binlog.000005 | 490 | +-----------------------+-----------+ --此时可以看到相应的gtid_purged值 (root@Master)[tempdb]>show variables like '%gtid_purged%'; +---------------+--------------------------------------------+ | Variable_name | Value | +---------------+--------------------------------------------+ | gtid_purged | 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-101 | +---------------+--------------------------------------------+ --下面启动从库 (root@Slave)[tempdb]>start slave; Query OK, 0 rows affected (0.00 sec) --从库状态提示有日志被purged (root@Slave)[tempdb]>show slave status\G*************************** 1. row *************************** Slave_IO_State: Master_Host: Master Master_User: repl Master_Port: 3306 Connect_Retry: 60 Master_Log_File: node233-binlog.000004 Read_Master_Log_Pos: 7121 Relay_Log_File: node245-relay-bin.000003 Relay_Log_Pos: 3133 Relay_Master_Log_File: node233-binlog.000004 Slave_IO_Running: No Slave_SQL_Running: Yes ............... Last_IO_Errno: 1236 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.' .................. Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-100 Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-100, 78336cdc-8cfb-11e6-ba9f-000c29328504:1-4 Auto_Position: 1-- 从库上gtid_purged参数，此时为75 (root@Slave)[tempdb]>show variables like '%gtid_purged%'; +---------------+-------------------------------------------+ | Variable_name | Value | +---------------+-------------------------------------------+ | gtid_purged | 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-75 | +---------------+-------------------------------------------+ --停止从库 (root@Slave)[tempdb]>stop slave; Query OK, 0 rows affected (0.01 sec) --下面尝试使用gtid_purged进行跳过事务，，如下，提示仅仅当GLOBAL.GTID_EXECUTED为空才能被设置 (root@Slave)[tempdb]>set global gtid_purged = '1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-101'; ERROR 1840 (HY000): @@GLOBAL.GTID_PURGED can only be set when @@GLOBAL.GTID_EXECUTED is empty. --如下查看，已经存在被执行的gtid，即gtid_executed肯定是不为空，且这些gtid记录在从库的binary log中 (root@Slave)[tempdb]>show global variables like '%gtid_executed%'\G*************************** 1. row ***************************Variable_name: gtid_executed Value: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-100, 78336cdc-8cfb-11e6-ba9f-000c29328504:1-4*************************** 2. row ***************************Variable_name: gtid_executed_compression_period Value: 1000--下面我们在从库上reset master，即清空从库binlog (root@Slave)[tempdb]>reset master; Query OK, 0 rows affected (0.05 sec) --再次查看gtid_executed已经为空值 (root@Slave)[tempdb]>show global variables like '%gtid_executed%'\G*************************** 1. row ***************************Variable_name: gtid_executed Value: *************************** 2. row ***************************Variable_name: gtid_executed_compression_period Value: 1000--此时再次设置gtid_purged的值 (root@Slave)[tempdb]>set global gtid_purged = '1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-101'; Query OK, 0 rows affected (0.01 sec) --启动从库 (root@Slave)[tempdb]>start slave; Query OK, 0 rows affected (0.03 sec) --提示有重复记录，如下所示 --是由于我们在从库停止期间delete这个事务没有被从库的relay log接受到 --其次主从的binlog又被purged，而且从库启动后，执行了gtid_purged，因此主库上新增的记录在从库上提示主键重复 (root@Slave)[tempdb]>show slave status \G*************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: Master Master_User: repl Master_Port: 3306 Connect_Retry: 60 Master_Log_File: node233-binlog.000005 Read_Master_Log_Pos: 490 Relay_Log_File: node245-relay-bin.000004 Relay_Log_Pos: 417 Relay_Master_Log_File: node233-binlog.000005 Slave_IO_Running: Yes Slave_SQL_Running: No ................ Last_SQL_Error: Could not execute Write_rows event on table tempdb.t1; Duplicate entry '1' for key 'PRIMARY', Error_code: 1062; handler error HA_ERR_FOUND_DUPP_KEY; the event's master log node233-binlog.000005, end_log_pos 459 Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-100:102 Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-101 Auto_Position: 1--在从库上删除id为1的记录 (root@Slave)[tempdb]>delete from t1 where id=1; Query OK, 1 row affected (0.05 sec) --启动从库的sql_thread线程 (root@Slave)[tempdb]>start slave sql_thread; Query OK, 0 rows affected (0.02 sec) --再次查看正常 (root@Slave)[tempdb]>show slave status \G*************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: Master Master_User: repl Master_Port: 3306 Connect_Retry: 60 Master_Log_File: node233-binlog.000005 Read_Master_Log_Pos: 490 Relay_Log_File: node245-relay-bin.000004 Relay_Log_Pos: 713 Relay_Master_Log_File: node233-binlog.000005 Slave_IO_Running: Yes Slave_SQL_Running: Yes--上面的这个示例，主要是演示我们使用gtid_purged方式来达到跳过事务的目的 --事实上，主从的数据已经不一致了，应根据实际的需要考虑是否进行相应的修复
1、GTID是全局事务ID，简化了主从架构的部署使得从库不再需要关心log_file和log_pos
2、由于事务ID的唯一性，使得将其他从库的GTID应用到其它从库成为可能，即提供了便利的failover
3、GTID是连续的，非空洞性的，因此，对于冲突的情形，需要注入空的事务来实现
4、可以通过配置延迟从来避免主库上意外的删除对象导致的人为错误
MySQL GTID是在传统的mysql主从复制的基础之上演化而来的产物，即通过UUID加上事务ID的方式来确保每一个事物的唯一性。这样的操作方式使得我们不再需要关心所谓的log_file和log_Pos，只是简单的告诉从库，从哪个服务器上去找主库就OK了。简化了主从的搭建以及failover的过程，同时比传统的复制更加安全可靠。由于GTID是连续没有空洞的，因此主从库出现数据冲突时，可以通过注入空事物的方式进行跳过。本文主要讲述GTID主从架构的错误处理方式。
配置MySQL GTID 主从复制
基于mysqldump搭建gtid主从
很多无法预料的情形导致mysql主从发生事务冲突，主从失败或停止的情形，即需要修复主从
对于GTID方式的主从架构而言，更多的是处理事务冲突来修复主从
GTID不支持通过传统设置sql_slave_skip_counter方法来跳过事务
方法：通过注入空事务来填补事务空洞，等同于传统复制的(set global sql_slave_skip_counter = 1)
步骤：
stop slave；
set gtid_next='xxxxxxx:N'; --指定下一个事务执行的版本，即想要跳过的GTID
begin;
commit; --注入一个空事物
set gtid_next='AUTOMATIC' --自动的寻找GTID事务。
start slave; --开始同步 1、主库新增记录，从库提示主键冲突
2、主库对象可更新，从库无对应的对象可更新
3、主库对象可删除，从库无对应的对象可删除
4、通过延迟从修复主库意外删除的对象
5、主库日志被purged的情形当前演示的主从架构图 # mysqlrplshow --master=root:pass@192.168.1.233:3306 --discover-slaves-login=root:pass --verboseWARNING: Using a password on the command line interface can be insecure. # master on 192.168.1.233: ... connected. # Finding slaves for master: 192.168.1.233:3306 # Replication Topology Graph 192.168.1.233:3306 (MASTER) | +--- 192.168.1.245:3306 [IO: Yes, SQL: Yes] - (SLAVE) | +--- 192.168.1.247:3306 [IO: Yes, SQL: Yes] - (SLAVE)(root@192.168.1.233)[tempdb]>show slave hosts;+-----------+---------------+------+-----------+--------------------------------------+| Server_id | Host | Port | Master_id | Slave_UUID | +-----------+---------------+------+-----------+--------------------------------------+| 245 | 192.168.1.245 | 3306 | 233 | 78336cdc-8cfb-11e6-ba9f-000c29328504 || 247 | 192.168.1.247 | 3306 | 233 | 13a26fc1-555a-11e6-b5e0-000c292e1642 | +-----------+---------------+------+-----------+--------------------------------------+--演示的mysql版本 (root@192.168.1.233)[tempdb]>show variables like 'version';+---------------+------------+| Variable_name | Value | +---------------+------------+| version | 5.7.12-log | +---------------+------------+--查看gtid是否开启 (root@192.168.1.233)[tempdb]>show variables like '%gtid_mode%';+---------------+-------+| Variable_name | Value | +---------------+-------+| gtid_mode | ON | +---------------+-------+--主库上面可以看到基于gtid的dump线程，如下 (root@192.168.1.233)[tempdb]>show processlist;+----+------+-----------------------+--------+------------------+------+| Id | User | Host | db | Command | Time | +----+------+-----------------------+--------+------------------+------+| 17 | repl | node245.edq.com:52685 | NULL | Binlog Dump GTID | 2738 | | 18 | repl | node247.edq.com:33516 | NULL | Binlog Dump GTID | 2690 || 24 | root | localhost | tempdb | Query | 0 | +----+------+-----------------------+--------+------------------+------+
(root@Master)[tempdb]>create table t1 (
-> id tinyint not null primary key,ename varchar(20),blog varchar(50));
(root@Master)[tempdb]>insert into t1
-> values(1,'leshami','http://blog.csdn.net/leshami');
(root@Master)[tempdb]>insert into t1
-> values(2,'robin','http://blog.csdn.net/robinson_0612');
(root@Master)[tempdb]>set sql_log_bin=off;
(root@Master)[tempdb]>delete from t1 where ename='robin';
(root@Master)[tempdb]>set sql_log_bin=on;
(root@Master)[tempdb]>insert into t1
-> values(2,'robin','http://blog.csdn.net/robinson_0612');
-- 从库状态报错，提示重复的primary key
(root@Slave)[tempdb]>show slave status \G
*************************** 1. row ***************************Last_Errno: 1062Last_Error: Could not execute Write_rows event on table tempdb.t1; Duplicate entry '2' for key 'PRIMARY',
Error_code: 1062; handler error HA_ERR_FOUND_DUPP_KEY;
the event's master log node233-binlog.000004, end_log_pos 4426
Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-90
Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-89
Auto_Position: 1
-- 如下解决方案，可以通过删除重库的这条记录
(root@Slave)[tempdb]>stop slave;
(root@Slave)[tempdb]>delete from t1 where ename='robin';
(root@Slave)[tempdb]>start slave;
(root@Slave)[tempdb]>show slave status \G
*************************** 1. row ***************************
Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-90
Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-90,
78336cdc-8cfb-11e6-ba9f-000c29328504:1 --这里多了一个GTID，注意这个是从库上执行的，这里的UUID跟IP 245的UUID一致
Auto_Position: 1
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
(root@Slave)[tempdb]>show variables like '%uuid%';
+---------------+--------------------------------------+
| Variable_name | Value |
+---------------+--------------------------------------+
| server_uuid | 78336cdc-8cfb-11e6-ba9f-000c29328504 |
+---------------+--------------------------------------+--首先在从库上删除leshami这条记录
(root@Slave)[tempdb]>delete from t1 where ename='leshami';
--接下来再主库尝试更新leshami这条记录
(root@Master)[tempdb]>update t1 set
-> blog='http://blog.csdn.net/robinson_0612' where ename='leshami';Query OK, 1 row affected (0.02 sec)
Rows matched: 1 Changed: 1 Warnings: 0
-- 查看从库状态
(root@Slave)[tempdb]>show slave status \G*************************** 1. row ***************************Last_SQL_Errno: 1032
Last_SQL_Error: Could not execute Update_rows event on table tempdb.t1; Can't find record in 't1', Error_code: 1032; handler error HA_ERR_KEY_NOT_FOUND; the event's master log node233-binlog.000004, end_log_pos 4769Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-91
Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-90, 78336cdc-8cfb-11e6-ba9f-000c29328504:1-2-- 通过mysqlbinlog在主服务器上寻找报错的binglog日志文件及位置，找到对应的SQL语句，如下所示
-- update中的where后面的部分为更新前的数据，set部分为更新后的数据，因此可以将更新前的数据插入到从库# mysqlbinlog --no-defaults -v -v --base64-output=DECODE-ROWS /data/node233-binlog.000004|grep -A '10' 4769#161009 13:46:34 server id 233 end_log_pos 4769 CRC32 0xb60df74e Update_rows: table id 147 flags: STMT_END_F### UPDATE `tempdb`.`t1`### WHERE### @1=1 /* TINYINT meta=0 nullable=0 is_null=0 */### @2='leshami' /* VARSTRING(20) meta=20 nullable=1 is_null=0 */### @3='http://blog.csdn.net/leshami' /* VARSTRING(50) meta=50 nullable=1 is_null=0 */### SET### @1=1 /* TINYINT meta=0 nullable=0 is_null=0 */### @2='leshami' /* VARSTRING(20) meta=20 nullable=1 is_null=0 */### @3='http://blog.csdn.net/robinson_0612' /* VARSTRING(50) meta=50 nullable=1 is_null=0 */# at 4769#161009 13:46:34 server id 233 end_log_pos 4800 CRC32 0xa9669811 Xid = 1749COMMIT/*!*/;
SET @@SESSION.GTID_NEXT= 'AUTOMATIC' /* added by mysqlbinlog */ /*!*/;
DELIMITER ;# End of log file/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;
(root@Slave)[tempdb]>select * from t1;
+----+-------+------------------------------------+
| id | ename | blog |
+----+-------+------------------------------------+
| 2 | robin | http://www.gxlcms.com/ |
+----+-------+------------------------------------+
(root@Slave)[tempdb]>stop slave sql_thread;
(root@Slave)[tempdb]>insert into t1 values(1,'leshami','http://blog.csdn.net/leshami');
(root@Slave)[tempdb]>start slave sql_thread;
(root@Slave)[tempdb]>show slave status \G*************************** 1. row *************************** Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-91 Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-91, 78336cdc-8cfb-11e6-ba9f-000c29328504:1-3 Auto_Position: 1-- 如果是在主库上删除记录，而从库上找不到对应的记录，则可以直接跳过该事务 -- 下面我们首选在从库上删除一条记录 (root@Slave)[tempdb]>delete from t1 where ename='robin'; -- 接下来在主库上删除该记录 (root@Master)[tempdb]>delete from t1 where ename='robin'; -- 从库端提示无法找到对应的记录 (root@Slave)[tempdb]>show slave status \G*************************** 1. row ***************************Last_SQL_Error: Could not execute Delete_rows event on table tempdb.t1; Can't find record in 't1', Error_code: 1032; handler error HA_ERR_KEY_NOT_FOUND; the event's master log node233-binlog.000004, end_log_pos 5070Last_SQL_Error_Timestamp: 161009 15:08:06 Master_SSL_Crl: Master_SSL_Crlpath: Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-92 Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-91, 78336cdc-8cfb-11e6-ba9f-000c29328504:1-4 Auto_Position: 1 -- 下面通过注入空事务来跳过 (root@Slave)[tempdb]>stop slave sql_thread; (root@Slave)[tempdb]>set gtid_next='1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:92'; (root@Slave)[tempdb]>begin;commit; (root@Slave)[tempdb]>set gtid_next='AUTOMATIC'; (root@Slave)[tempdb]>start slave sql_thread; (root@Slave)[tempdb]>show slave status \G*************************** 1. row *************************** Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-92 Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-92, 78336cdc-8cfb-11e6-ba9f-000c29328504:1-4 Auto_Position: 1 Replicate_Rewrite_DB: Channel_Name: Master_TLS_Version:
-- 主库上面新增表及记录
(root@Master)[tempdb]>create table t2 (id tinyint not null primary key,
-> ename varchar(20),blog varchar(50));(root@Master)[tempdb]>insert into t2
-> values(1,'leshami','http://blog.csdn.net/leshami');(root@Master)[tempdb]>insert into t2
-> values(2,'robin','http://blog.csdn.net/robinson_0612');(root@Master)[tempdb]>select * from t2;
+----+---------+------------------------------------+
| id | ename | blog |
+----+---------+------------------------------------+
| 1 | leshami | http://www.gxlcms.com/ |
| 2 | robin | http://www.gxlcms.com/ |
+----+---------+------------------------------------+
--先将从库配置为延迟从
(root@Slave)[tempdb]>stop slave sql_thread;
Query OK, 0 rows affected (0.01 sec)
(root@Slave)[tempdb]>CHANGE MASTER TO MASTER_DELAY = 300;
Query OK, 0 rows affected (0.00 sec)
(root@Slave)[tempdb]>start slave sql_thread;
Query OK, 0 rows affected (0.02 sec)
(root@Slave)[tempdb]>show slave status \G*************************** 1. row *************************** Slave_IO_Running: Yes Slave_SQL_Running: Yes SQL_Delay: 300 root@Slave)[tempdb]>show slave status \G*************************** 1. row *************************** Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-99 Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-99, 78336cdc-8cfb-11e6-ba9f-000c29328504:1-4 Auto_Position: 1--查看主库上的binglog gtid
(root@Master)[tempdb]>show master status\G*************************** 1. row *************************** File: node233-binlog.000004 Position: 6970 Binlog_Do_DB:
Binlog_Ignore_DB:
Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-99
1 row in set (0.00 sec)
--在主库上truncate t2
(root@Master)[tempdb]>truncate table t2;
Query OK, 0 rows affected (0.03 sec)
--再次查看主库上的binglog gtid，有99变成了100，这个100即是我们需要跳过的ID
(root@Master)[tempdb]>show master status\G*************************** 1. row *************************** File: node233-binlog.000004 Position: 7121 Binlog_Do_DB:
Binlog_Ignore_DB:
Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-100
1 row in set (0.00 sec)
--从库上跳过被意外truncate的事务
(root@Slave)[tempdb]>stop slave sql_thread;
Query OK, 0 rows affected (0.01 sec)
(root@Slave)[tempdb]>set gtid_next='1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:100';
Query OK, 0 rows affected (0.00 sec)
(root@Slave)[tempdb]>begin;commit;
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.01 sec)
(root@Slave)[tempdb]>set gtid_next='AUTOMATIC';
Query OK, 0 rows affected (0.00 sec)
(root@Slave)[tempdb]>start slave sql_thread;
Query OK, 0 rows affected (0.02 sec)
(root@Slave)[tempdb]>show slave status \G*************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: Master Master_User: repl Master_Port: 3306 Connect_Retry: 60 Master_Log_File: node233-binlog.000004 Read_Master_Log_Pos: 7121 Relay_Log_File: node245-relay-bin.000003 Relay_Log_Pos: 2982 Relay_Master_Log_File: node233-binlog.000004 Slave_IO_Running: Yes Slave_SQL_Running: Yes ........................... Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-100 Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-100, 78336cdc-8cfb-11e6-ba9f-000c29328504:1-4 Auto_Position: 1-- 很多时候我们并不知道表何时被truncate，因此可以从binlog日志得到其gtid
-- 如下所示，可以得到这串 SET @@SESSION.GTID_NEXT= '1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:100'
-- 100即为这个truncate对应的gtid的事务号# mysqlbinlog --no-defaults -v -v --base64-output=DECODE-ROWS /data/node233-binlog.000004|grep -i \> "truncate table t2" -A3 -B10 ### @3='http://blog.csdn.net/robinson_0612' /* VARSTRING(50) meta=50 nullable=1 is_null=0 */# at 6939#161009 18:04:58 server id 233 end_log_pos 6970 CRC32 0x71c5121c Xid = 1775COMMIT/*!*/;# at 6970#161009 18:08:42 server id 233 end_log_pos 7035 CRC32 0x00ba9437 GTID last_committed=26 sequence_number=27SET @@SESSION.GTID_NEXT= '1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:100'/*!*/;# at 7035#161009 18:08:42 server id 233 end_log_pos 7121 CRC32 0x5a8b9723 Query thread_id=26 exec_time=0 error_code=0SET TIMESTAMP=1476007722/*!*/;
truncate table t2
/*!*/;
SET @@SESSION.GTID_NEXT= 'AUTOMATIC' /* added by mysqlbinlog */ /*!*/;
DELIMITER ;-- 首先停止从库，模拟从库被意外宕机 (root@Slave)[tempdb]>stop slave; Query OK, 0 rows affected (0.08 sec) --在主库上进行相应的操作 --此时主库上的gtid_purged为空 (root@Master)[tempdb]>show variables like '%gtid_purged%'; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | gtid_purged | | +---------------+-------+ --查看主库binlog (root@Master)[tempdb]>show binary logs; +-----------------------+-----------+ | Log_name | File_size | +-----------------------+-----------+ | node233-binlog.000001 | 1362104 | | node233-binlog.000002 | 1331 | | node233-binlog.000003 | 217 | | node233-binlog.000004 | 7121 | +-----------------------+-----------+ (root@Master)[tempdb]>select * from t1; +----+---------+------------------------------------+ | id | ename | blog | +----+---------+------------------------------------+ | 1 | leshami | http://www.gxlcms.com/ | | 2 | robin | http://www.gxlcms.com/ | +----+---------+------------------------------------+ --从主库删除记录 (root@Master)[tempdb]>delete from t1; --切换日志 (root@Master)[tempdb]>flush logs; --新增记录 (root@Master)[tempdb]>insert into t1 values(1, -> 'xuputi','http://blog.csdn.net/leshami');(root@Master)[tempdb]>show binary logs; +-----------------------+-----------+ | Log_name | File_size | +-----------------------+-----------+ | node233-binlog.000001 | 1362104 | | node233-binlog.000002 | 1331 | | node233-binlog.000003 | 217 | | node233-binlog.000004 | 7513 | | node233-binlog.000005 | 490 | +-----------------------+-----------+ --清理binlog (root@Master)[tempdb]>purge binary logs to 'node233-binlog.000005'; Query OK, 0 rows affected (0.01 sec) (root@Master)[tempdb]>show binary logs; +-----------------------+-----------+ | Log_name | File_size | +-----------------------+-----------+ | node233-binlog.000005 | 490 | +-----------------------+-----------+ --此时可以看到相应的gtid_purged值 (root@Master)[tempdb]>show variables like '%gtid_purged%'; +---------------+--------------------------------------------+ | Variable_name | Value | +---------------+--------------------------------------------+ | gtid_purged | 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-101 | +---------------+--------------------------------------------+ --下面启动从库 (root@Slave)[tempdb]>start slave; Query OK, 0 rows affected (0.00 sec) --从库状态提示有日志被purged (root@Slave)[tempdb]>show slave status\G*************************** 1. row *************************** Slave_IO_State: Master_Host: Master Master_User: repl Master_Port: 3306 Connect_Retry: 60 Master_Log_File: node233-binlog.000004 Read_Master_Log_Pos: 7121 Relay_Log_File: node245-relay-bin.000003 Relay_Log_Pos: 3133 Relay_Master_Log_File: node233-binlog.000004 Slave_IO_Running: No Slave_SQL_Running: Yes ............... Last_IO_Errno: 1236 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.' .................. Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-100 Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-100, 78336cdc-8cfb-11e6-ba9f-000c29328504:1-4 Auto_Position: 1-- 从库上gtid_purged参数，此时为75 (root@Slave)[tempdb]>show variables like '%gtid_purged%'; +---------------+-------------------------------------------+ | Variable_name | Value | +---------------+-------------------------------------------+ | gtid_purged | 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-75 | +---------------+-------------------------------------------+ --停止从库 (root@Slave)[tempdb]>stop slave; Query OK, 0 rows affected (0.01 sec) --下面尝试使用gtid_purged进行跳过事务，，如下，提示仅仅当GLOBAL.GTID_EXECUTED为空才能被设置 (root@Slave)[tempdb]>set global gtid_purged = '1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-101'; ERROR 1840 (HY000): @@GLOBAL.GTID_PURGED can only be set when @@GLOBAL.GTID_EXECUTED is empty. --如下查看，已经存在被执行的gtid，即gtid_executed肯定是不为空，且这些gtid记录在从库的binary log中 (root@Slave)[tempdb]>show global variables like '%gtid_executed%'\G*************************** 1. row ***************************Variable_name: gtid_executed Value: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-100, 78336cdc-8cfb-11e6-ba9f-000c29328504:1-4*************************** 2. row ***************************Variable_name: gtid_executed_compression_period Value: 1000--下面我们在从库上reset master，即清空从库binlog (root@Slave)[tempdb]>reset master; Query OK, 0 rows affected (0.05 sec) --再次查看gtid_executed已经为空值 (root@Slave)[tempdb]>show global variables like '%gtid_executed%'\G*************************** 1. row ***************************Variable_name: gtid_executed Value: *************************** 2. row ***************************Variable_name: gtid_executed_compression_period Value: 1000--此时再次设置gtid_purged的值 (root@Slave)[tempdb]>set global gtid_purged = '1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-101'; Query OK, 0 rows affected (0.01 sec) --启动从库 (root@Slave)[tempdb]>start slave; Query OK, 0 rows affected (0.03 sec) --提示有重复记录，如下所示 --是由于我们在从库停止期间delete这个事务没有被从库的relay log接受到 --其次主从的binlog又被purged，而且从库启动后，执行了gtid_purged，因此主库上新增的记录在从库上提示主键重复 (root@Slave)[tempdb]>show slave status \G*************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: Master Master_User: repl Master_Port: 3306 Connect_Retry: 60 Master_Log_File: node233-binlog.000005 Read_Master_Log_Pos: 490 Relay_Log_File: node245-relay-bin.000004 Relay_Log_Pos: 417 Relay_Master_Log_File: node233-binlog.000005 Slave_IO_Running: Yes Slave_SQL_Running: No ................ Last_SQL_Error: Could not execute Write_rows event on table tempdb.t1; Duplicate entry '1' for key 'PRIMARY', Error_code: 1062; handler error HA_ERR_FOUND_DUPP_KEY; the event's master log node233-binlog.000005, end_log_pos 459 Retrieved_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:76-100:102 Executed_Gtid_Set: 1b64c25d-8d2b-11e6-9ac0-000c29b82d0d:1-101 Auto_Position: 1--在从库上删除id为1的记录 (root@Slave)[tempdb]>delete from t1 where id=1; Query OK, 1 row affected (0.05 sec) --启动从库的sql_thread线程 (root@Slave)[tempdb]>start slave sql_thread; Query OK, 0 rows affected (0.02 sec) --再次查看正常 (root@Slave)[tempdb]>show slave status \G*************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: Master Master_User: repl Master_Port: 3306 Connect_Retry: 60 Master_Log_File: node233-binlog.000005 Read_Master_Log_Pos: 490 Relay_Log_File: node245-relay-bin.000004 Relay_Log_Pos: 713 Relay_Master_Log_File: node233-binlog.000005 Slave_IO_Running: Yes Slave_SQL_Running: Yes--上面的这个示例，主要是演示我们使用gtid_purged方式来达到跳过事务的目的 --事实上，主从的数据已经不一致了，应根据实际的需要考虑是否进行相应的修复
1、GTID是全局事务ID，简化了主从架构的部署使得从库不再需要关心log_file和log_pos
2、由于事务ID的唯一性，使得将其他从库的GTID应用到其它从库成为可能，即提供了便利的failover
3、GTID是连续的，非空洞性的，因此，对于冲突的情形，需要注入空的事务来实现
4、可以通过配置延迟从来避免主库上意外的删除对象导致的人为错误
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