前言
在發生故障切換后，經常遇到的問題就是同步報錯，下面是最近收集的報錯信息。
記錄刪除失敗
在master上刪除一條記錄，而slave上找不到
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解決方法：master要刪除一條記錄，而slave上找不到報錯，這種情況主都已經刪除了，那么從機可以直接跳過。
stop slave; set global sql_slave_skip_counter=1; start slave;如果這種情況很多，需要針對這種錯誤專門寫相關腳本。
主鍵重復
在slave已經有該記錄，又在master上插入了同一條記錄。
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解決方法：
在slave上用desc hcy.t1; 先看下表結構：
mysql> desc hcy.t1; +-------+---------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+---------+------+-----+---------+-------+ | id | int(11) | NO | PRI | 0 | | | name | char(4) | YES | | NULL | | +-------+---------+------+-----+---------+-------+刪除重復的主鍵
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上再分別確認一下。
更新丟失
在master上更新一條記錄，而slave上找不到，丟失了數據。
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解決方法：
在master上，用mysqlbinlog 分析下出錯的binlog日志在干什么。
/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，查找下更新后的那條記錄，應該是不存在的。
mysql> select * from t1 where id=2; Empty set (0.00 sec)然后再到master查看
mysql> select * from t1 where id=2; +----+------+ | id | name | +----+------+ | 2 | BTV | +----+------+ 1 row in set (0.00 sec)把丟失的數據在slave上填補，然后跳過報錯即可。
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錯誤, 二進制文件缺失
誤刪二進制文件等各種原因，導致主庫mysql-bin.000012文件丟失，從庫同步失敗。
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'-
首先停止從庫同步
slave stop; -
查看主庫日志文件和位置
mysql> show master logs; +------------------+-----------+ | Log_name | File_size | +------------------+-----------+ | mysql-bin.000013 | 154 | +------------------+-----------+ -
回從庫，使日志文件和位置對應主庫
CHANGE MASTER TO MASTER_LOG_FILE='log-bin.000013',MASTER_LOG_POS=154; -
最后，啟動從庫：
```bash
slave start;
show slave status\G;
Master_Log_File: mysql-bin.000013
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Last_IO_Error:
```
中繼日志損壞
slave的中繼日志relay-bin損壞。
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 MySQL1、手工修復
解決方法：找到同步的binlog和POS點，然后重新做同步，這樣就可以有新的中繼日值了。
例子：
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：執行寫操作 Relay_Master_Log_File Exec_Master_Log_Pos以執行寫的binlog和POS點為准。
Relay_Master_Log_File: mysql-bin.000010 Exec_Master_Log_Pos: 821mysql> 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: