Mysql传统复制空库搭建过程中reset slave以及reset slave all对复制的影响

Mysql传统复制空库搭建过程中reset
slave以及reset slave all对复制的影响
主库信息
从库信息
操作过程
主库上操作
从库上操作
主库上查看
解决方法
思路探讨
参考资料

Mysql传统复制空库搭建过程中reset slave以及reset slave all对复制的影响

主库信息

IP：192.168.1.21
版本：5.7.18
空库搭建主从

从库信息

IP：192.168.1.128
版本：5.6.36
空库搭建主从

操作过程

主库上操作

赋予复制账户:

mysql> GRANT REPLICATION SLAVE ON *.* TO 'repl'@'192.168.1.128' IDENTIFIED by 'repl';

查看master信息：

mysql> show master status;

+------------------+----------+--------------+------------------+-------------------+

| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |

+------------------+----------+--------------+------------------+-------------------+

| mysql-bin.000022 |      612 |              |                  |                   |

+------------------+----------+--------------+------------------+-------------------+

1 row in set (0.00 sec)

从库上操作

直接指定新的master：

root@localhost : (none) 05:16:09> change master to master_host='192.168.1.21',master_user='repl',master_password='repl',master_log_file='mysql-bin.000022',master_log_pos=612;

ERROR 1776 (HY000): Parameters MASTER_LOG_FILE, MASTER_LOG_POS, RELAY_LOG_FILE and RELAY_LOG_POS cannot be set when MASTER_AUTO_POSITION is active.

#报错是因为128这台mysql server之前是使用gtid复制指向另一台mysql主库；而且没有经过reset slave清理相关数据，直接指向新的master肯定也会有问题。

关闭gtid设置：

[root@host-192-168-1-128 ~]# service mysql stop

Shutting down MySQL.... SUCCESS!

[root@host-192-168-1-128 ~]# vim /etc/my.cnf 在配置文件中关闭gtid

#gtid-mode=on # GTID only

#enforce-gtid-consistency=true # GTID only

或者

enforce_gtid_consistency=OFF

gtid_mode=OFF

[root@host-192-168-1-128 ~]# service mysql start

Starting MySQL.. SUCCESS!

重新指定master，并开启slave：

root@localhost : (none) 05:19:34> change master to master_host='192.168.1.21',master_user='repl',master_password='repl',master_log_file='mysql-bin.000022',master_log_pos=612;

Query OK, 0 rows affected, 2 warnings (0.03 sec)

root@localhost : (none) 05:20:21> start slave;

ERROR 1872 (HY000): Slave failed to initialize relay log info structure from the repository

root@localhost : (none) 05:20:37> reset slave;

Query OK, 0 rows affected (0.03 sec)

root@localhost : (none) 05:20:56> start slave;

Query OK, 0 rows affected (0.10 sec)

查看复制情况：

root@localhost : (none) 05:20:57> show slave status\G;

*************************** 1. row ***************************

Slave_IO_State: Waiting for master to send event

Master_Host: 192.168.1.21

Master_User: repl

Master_Port: 3306

Connect_Retry: 60

Master_Log_File: mysql-bin.000022

Read_Master_Log_Pos: 612

Relay_Log_File: mysql-relay-bin.000005

Relay_Log_Pos: 333

Relay_Master_Log_File: mysql-bin.000022

Slave_IO_Running: Yes

Slave_SQL_Running: No

Replicate_Do_DB:

Replicate_Ignore_DB:

Replicate_Do_Table:

Replicate_Ignore_Table:

Replicate_Wild_Do_Table:

Replicate_Wild_Ignore_Table:

Last_Errno: 1008

Last_Error: Error 'Can't drop database 'sbtest'; database doesn't exist' on query. Default database: 'sbtest'. Query: 'drop database sbtest'

Skip_Counter: 0

Exec_Master_Log_Pos: 154

Relay_Log_Space: 964

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: NULL

Master_SSL_Verify_Server_Cert: No

Last_IO_Errno: 0

Last_IO_Error:

Last_SQL_Errno: 1008

Last_SQL_Error: Error 'Can't drop database 'sbtest'; database doesn't exist' on query. Default database: 'sbtest'. Query: 'drop database sbtest'

Replicate_Ignore_Server_Ids:

Master_Server_Id: 12001

Master_UUID: 0a646c88-36e2-11e7-937d-fa163ed7a7b1

Master_Info_File: mysql.slave_master_info

SQL_Delay: 0

SQL_Remaining_Delay: NULL

Slave_SQL_Running_State:

Master_Retry_Count: 86400

Master_Bind:

Last_IO_Error_Timestamp:

Last_SQL_Error_Timestamp: 170516 05:20:58

Master_SSL_Crl:

Master_SSL_Crlpath:

Retrieved_Gtid_Set:

Executed_Gtid_Set:

Auto_Position: 0

1 row in set (0.00 sec)

# 注意Exec_Master_Log_Pos: 154

主库上查看

查看主库binlog中的events：

mysql> show binlog events in 'mysql-bin.000022';

+------------------+-----+----------------+-----------+-------------+-------------------------------------------------------------------------------------------------------------------------------------------------+

| Log_name         | Pos | Event_type     | Server_id | End_log_pos | Info                                                                                                                                            |

+------------------+-----+----------------+-----------+-------------+-------------------------------------------------------------------------------------------------------------------------------------------------+

| mysql-bin.000022 |   4 | Format_desc    |     12001 |         123 | Server ver: 5.7.18-log, Binlog ver: 4                                                                                                           |

| mysql-bin.000022 | 123 | Previous_gtids |     12001 |         154 |                                                                                                                                                 |

| mysql-bin.000022 | 154 | Anonymous_Gtid |     12001 |         219 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS'                                                                                                            |

| mysql-bin.000022 | 219 | Query          |     12001 |         317 | drop database sbtest                                                                                                                            |

| mysql-bin.000022 | 317 | Anonymous_Gtid |     12001 |         382 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS'                                                                                                            |

| mysql-bin.000022 | 382 | Query          |     12001 |         612 | GRANT REPLICATION SLAVE ON *.* TO 'repl'@'192.168.1.128' IDENTIFIED WITH 'mysql_native_password' AS '*A424E797037BF97C19A2E88CF7891C5C2038C039' |

+------------------+-----+----------------+-----------+-------------+-------------------------------------------------------------------------------------------------------------------------------------------------+

6 rows in set (0.00 sec)

# 对比slave的Exec_Master_Log_Pos: 154，确实会去执行drop database sbtest。问题来了：为什么我指定的master_log_pos=612但是却会执行这个位置之前的binlog日志？

解决方法

先关闭slave：

root@localhost : (none) 05:39:13> stop slave;

Query OK, 0 rows affected (0.02 sec)

清空master.info文件和relay-log.info 文件以及所有的relay log 文件，all也包括在内存中的信息：

root@localhost : (none) 05:39:17> reset slave all;

Query OK, 0 rows affected (0.08 sec)

重新指定master并开启slave：

root@localhost : (none) 05:39:26> change master to master_host='192.168.1.21',master_user='repl',master_password='repl',master_log_file='mysql-bin.000022',master_log_pos=612;

Query OK, 0 rows affected, 2 warnings (0.10 sec)

root@localhost : (none) 05:39:44> start slave;

Query OK, 0 rows affected (0.02 sec)

查看复制情况：

root@localhost : (none) 05:39:48> show slave status\G;

*************************** 1. row ***************************

Slave_IO_State: Waiting for master to send event

Master_Host: 192.168.1.21

Master_User: repl

Master_Port: 3306

Connect_Retry: 60

Master_Log_File: mysql-bin.000022

Read_Master_Log_Pos: 612

Relay_Log_File: mysql-relay-bin.000002

Relay_Log_Pos: 286

Relay_Master_Log_File: mysql-bin.000022

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: 612

Relay_Log_Space: 459

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: 12001

Master_UUID: 0a646c88-36e2-11e7-937d-fa163ed7a7b1

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 the slave I/O thread to update it

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:

Auto_Position: 0

1 row in set (0.00 sec)

思路探讨

reset slave删除master.info文件和relay-log.info 文件以及所有的relay log 文件并重新启用一个新的relaylog文件，但并不会清理存储于内存中的复制信息比如master host, master port, master user, or master password,也就是说如果没有使用change master 命令做重新定向，执行start slave 还是会指向旧的master 上面。
在5.5.16 版本以及以后，可以使用 RESET SLAVE ALL 来完全的清理复制连接参数信息。 

In MySQL 5.5.16 and later, you can instead use RESET SLAVE ALL to reset these connection parameters
至于明明指定了master_log_pos=612，从库却执行了这之前的位置Exec_Master_Log_Pos: 154。 

猜测：这应该和128这个从库之前指定的是另一个master（192.168.1.12），而这些旧的信息还保存在内存中导致的。
当时出现错误的第一反应是用skip去跳过错误，问了小波之后说尝试下reset slave all，才能进一步去了解这其中的区别。

参考资料

https://www.percona.com/blog/2013/04/17/reset-slave-vs-reset-slave-all-disconnecting-a-replication-slave-is-easier-with-mysql-5-5/ 
https://dev.mysql.com/doc/refman/5.5/en/reset-slave.html