MySQL通过物理备份恢复后，配置主从复制报错案例

Posted 2021-03-28 DBA的辛酸事儿

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最经在通过物理备份恢复mysql实例后，和原来的主库之间配置主从复制关系；但是在配置过程中遇到1236报错的问题，下面我们来看下具体的情况；

场景描述

通过物理备份文件（从库的全量备份）恢复实例后，与主库建立主从复制关系，出现如下的报错信息：

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.'

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.'

恢复物理备份后，首先进行applylog操作

innobackupex --apply-log /data/mysql_4306/data/

查看物理备份文件中记录备份时候的GTID相关信息

cat data/xtrabackup_binlog_infomysqlbin.010299 1101521 17136423-a6e9-11e9-9b46-005056b7f430:1-14744282:14744284-52079172,7bd27dfa-a6e9-11e9-92df-005056b7552b:1-2

物理备份恢复后，创建主从复制的方式如下所示：

stop slave;reset slave all;reset master; set global gtid_purged="17136423-a6e9-11e9-9b46-005056b7f430:1-14744282:14744284-52079172,,7bd27dfa-a6e9-11e9-92df-005056b7552b:1-2"; CHANGE MASTER TO MASTER_HOST='10.21.124.118', MASTER_USER='dba_repl', MASTER_PASSWORD='replsafe', MASTER_PORT=4306, MASTER_AUTO_POSITION = 1; start slave;show slave status\G

配置好复制后，启动复制，复制出现如下的报错信息：

mysql> show slave status\G*************************** 1. row *************************** Slave_IO_State: Master_Host: 10.21.124.118 Master_User: dba_repl Master_Port: 4306 Connect_Retry: 60 Master_Log_File: mysqlbin.000714 Read_Master_Log_Pos: 454311663 Relay_Log_File: slave-relay-bin.000001 Relay_Log_Pos: 4 Relay_Master_Log_File: mysqlbin.000714 Slave_IO_Running: No 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: 454311663 Relay_Log_Space: 154 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: NULLMaster_SSL_Verify_Server_Cert: No 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.' Last_SQL_Errno: 0 Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 242 Master_UUID: 17136423-a6e9-11e9-9b46-005056b7f430 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: 200917 16:13:15 Last_SQL_Error_Timestamp: Master_SSL_Crl: Master_SSL_Crlpath: Retrieved_Gtid_Set: Executed_Gtid_Set: 17136423-a6e9-11e9-9b46-005056b7f430:1-14744282:14744284-52078201,7bd27dfa-a6e9-11e9-92df-005056b7552b:1-2 Auto_Position: 1 Replicate_Rewrite_DB: Channel_Name: Master_TLS_Version:1 row in set (0.00 sec)

从报错信息看，是由于从库在执行主库传输过来的binlog event的时候，发现主库的binlog已经被purge掉了

首先，查看主库的gtid相关信息

mysql>show master status;+-----------------+-----------+--------------+------------------+-------------------------------------------------+| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |+-----------------+-----------+--------------+------------------+-------------------------------------------------+| mysqlbin.000714 | 552383972 | | | 17136423-a6e9-11e9-9b46-005056b7f430:1-52127386 |+-----------------+-----------+--------------+------------------+-------------------------------------------------+1 row in set (0.00 sec)

原因分析

发现主库的GTID是连续的，而备份文件中的GTID是断开的，缺少14744283的事务，那么从库在执行到14744283事务的时候，发现主库的该事务已经被purge，所以出现了上述的报错情况

之所以从库的备份中出现GTID不连续的情况，有可能是由于在从库执行过空事务或跳过事务导致的

解决方案

在恢复的实例上重新设置gtid_purge

stop slave;reset slave all;reset master;set global gtid_purged="17136423-a6e9-11e9-9b46-005056b7f430:1-52079172,7bd27dfa-a6e9-11e9-92df-005056b7552b:1-2"; CHANGE MASTER TO MASTER_HOST='10.21.124.118', MASTER_USER='dba_repl', MASTER_PASSWORD='replsafe', MASTER_PORT=4306, MASTER_AUTO_POSITION = 1;

主从复制正常

start slave;show slave status\G*************************** 1. row *************************** Slave_IO_State: Checking master version Master_Host: 10.21.124.118 Master_User: dba_repl Master_Port: 4306 Connect_Retry: 60 Master_Log_File: Read_Master_Log_Pos: 4 Relay_Log_File: slave-relay-bin.000001 Relay_Log_Pos: 4 Relay_Master_Log_File: 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: 0 Relay_Log_Space: 154 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: 0Master_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: 0 Master_UUID: 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: 17136423-a6e9-11e9-9b46-005056b7f430:1-52079172,7bd27dfa-a6e9-11e9-92df-005056b7552b:1-2 Auto_Position: 1 Replicate_Rewrite_DB: Channel_Name: Master_TLS_Version:1 row in set (0.00 sec)

主从复制失败的场景比较多，针对不同的问题，采用不同的解决方案；

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