MySQL主从同步报错故障处理集锦

文章目录
  1. 1. 前言
  2. 2. 记录删除失败
  3. 3. 主键重复
  4. 4. 更新丢失
  5. 5. 1236错误, 二进制文件缺失
  6. 6. 中继日志损坏

前言

在发生故障切换后,经常遇到的问题就是同步报错,下面是最近收集的报错信息。


记录删除失败

在master上删除一条记录,而slave上找不到

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Last_SQL_Error: Could not execute Delete_rows event on table hcy.t1; 
Can't find record in 't1',
Error_code: 1032; handler error HA_ERR_KEY_NOT_FOUND;
the event's master log mysql-bin.000006, end_log_pos 254

解决方法:master要删除一条记录,而slave上找不到报错,这种情况主都已经删除了,那么从机可以直接跳过。

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stop slave;
set global sql_slave_skip_counter=1;
start slave;

如果这种情况很多,需要针对这种错误专门写相关脚本。


主键重复

在slave已经有该记录,又在master上插入了同一条记录。

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Last_SQL_Error: Could not execute Write_rows event on table hcy.t1; 
Duplicate entry '2' for key 'PRIMARY',
Error_code: 1062;
handler error HA_ERR_FOUND_DUPP_KEY; the event's master log mysql-bin.000006, end_log_pos 924

解决方法:

在slave上用desc hcy.t1; 先看下表结构:

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mysql> desc hcy.t1;
+-------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------+------+-----+---------+-------+
| id | int(11) | NO | PRI | 0 | |
| name | char(4) | YES | | NULL | |
+-------+---------+------+-----+---------+-------+

删除重复的主键

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mysql> delete from t1 where id=2;
Query OK, 1 row affected (0.00 sec)

mysql> start slave;
Query OK, 0 rows affected (0.00 sec)

mysql> show slave status\G;
……
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
……
mysql> select * from t1 where id=2;

在master上和slave上再分别确认一下。


更新丢失

在master上更新一条记录,而slave上找不到,丢失了数据。

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Last_SQL_Error: Could not execute Update_rows event on table hcy.t1; 
Can't find record in 't1',
Error_code: 1032;
handler error HA_ERR_KEY_NOT_FOUND;
the event's master log mysql-bin.000010, end_log_pos 794

解决方法:

在master上,用mysqlbinlog 分析下出错的binlog日志在干什么。

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/usr/local/mysql/bin/mysqlbinlog --no-defaults -v -v --base64-output=DECODE-ROWS mysql-bin.000010 | grep -A '10' 794

#120302 12:08:36 server id 22 end_log_pos 794 Update_rows: table id 33 flags: STMT_END_F
### UPDATE hcy.t1
### WHERE
### @1=2 /* INT meta=0 nullable=0 is_null=0 */
### @2='bbc' /* STRING(4) meta=65028 nullable=1 is_null=0 */
### SET
### @1=2 /* INT meta=0 nullable=0 is_null=0 */
### @2='BTV' /* STRING(4) meta=65028 nullable=1 is_null=0 */
# at 794
#120302 12:08:36 server id 22 end_log_pos 821 Xid = 60
COMMIT/*!*/;
DELIMITER ;
# End of log file
ROLLBACK /* added by mysqlbinlog */;
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;

在slave上,查找下更新后的那条记录,应该是不存在的。

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mysql> select * from t1 where id=2;
Empty set (0.00 sec)

然后再到master查看

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mysql> select * from t1 where id=2;
+----+------+
| id | name |
+----+------+
| 2 | BTV |
+----+------+
1 row in set (0.00 sec)

把丢失的数据在slave上填补,然后跳过报错即可。

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mysql> insert into t1 values (2,'BTV');
Query OK, 1 row affected (0.00 sec)

mysql> select * from t1 where id=2;
+----+------+
| id | name |
+----+------+
| 2 | BTV |
+----+------+
1 row in set (0.00 sec)

mysql> stop slave ;set global sql_slave_skip_counter=1;start slave;
Query OK, 0 rows affected (0.01 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.00 sec)

mysql> show slave status\G;
……
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
……


1236错误, 二进制文件缺失

误删二进制文件等各种原因,导致主库mysql-bin.000012文件丢失,从库同步失败。

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Master_Log_File: mysql-bin.000012
Slave_IO_Running: No
Slave_SQL_Running: Yes
Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: 'Could not find first log file name in binary log index file'

  • 首先停止从库同步

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    slave stop;
  • 查看主库日志文件和位置

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    mysql> show master logs;
    +------------------+-----------+
    | Log_name | File_size |
    +------------------+-----------+
    | mysql-bin.000013 | 154 |
    +------------------+-----------+
  • 回从库,使日志文件和位置对应主库

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    CHANGE MASTER TO MASTER_LOG_FILE='log-bin.000013',MASTER_LOG_POS=154;
  • 最后,启动从库:

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    slave start;

    show slave status\G;

    Master_Log_File: mysql-bin.000013
    Slave_IO_Running: Yes
    Slave_SQL_Running: Yes
    Last_IO_Error:

中继日志损坏

slave的中继日志relay-bin损坏。

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Last_SQL_Error: Error initializing relay log position: I/O error reading the header from the binary log
Last_SQL_Error: Error initializing relay log position: Binlog has bad magic number;
It's not a binary log file that can be used by this version of MySQL

1、手工修复
解决方法:找到同步的binlog和POS点,然后重新做同步,这样就可以有新的中继日值了。

例子:

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mysql> show slave status\G;
*************************** 1. row ***************************
Master_Log_File: mysql-bin.000010
Read_Master_Log_Pos: 1191
Relay_Log_File: vm02-relay-bin.000005
Relay_Log_Pos: 253
Relay_Master_Log_File: mysql-bin.000010
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: 1593
Last_Error: Error initializing relay log position: I/O error reading the header from the binary log
Skip_Counter: 1
Exec_Master_Log_Pos: 821

Slave_IO_Running :接收master的binlog信息
Master_Log_File
Read_Master_Log_Pos

Slave_SQL_Running:执行写操作
Relay_Master_Log_File
Exec_Master_Log_Pos

以执行写的binlog和POS点为准。

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Relay_Master_Log_File: mysql-bin.000010
Exec_Master_Log_Pos: 821

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mysql> stop slave;
Query OK, 0 rows affected (0.01 sec)

mysql> CHANGE MASTER TO MASTER_LOG_FILE='mysql-bin.000010',MASTER_LOG_POS=821;
Query OK, 0 rows affected (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: 192.168.8.22
Master_User: repl
Master_Port: 3306
Connect_Retry: 10
Master_Log_File: mysql-bin.000010
Read_Master_Log_Pos: 1191
Relay_Log_File: vm02-relay-bin.000002
Relay_Log_Pos: 623
Relay_Master_Log_File: mysql-bin.000010
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: 1191
Relay_Log_Space: 778
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:

2、Ibbackup
各种大招都用上了,无奈slave数据丢失过多,ibbackup(需要银子)该你登场了。

Ibbackup热备份工具,是付费的。xtrabackup是免费的,功能上一样。

Ibbackup备份期间不锁表,备份时开启一个事务(相当于做一个快照),然后会记录一个点,之后数据的更改保存在ibbackup_logfile文件里,恢复时把ibbackup_logfile 变化的数据再写入到ibdata里。

Ibbackup 只备份数据( ibdata、.ibd ),表结构.frm不备份。