目录
查看主从是否同步
详解Slave_IO、Slave_SQL
判断主从完全同步
各个 Log_File 和 Log_Pos的关系
修复命令
show slave status;
Slave_IO_Running、Slave_SQL_Running,这两个值是Yes表示正常,No是异常
使用竖排显示:
Name |Value |
-----------------------------+------------------------------------------------------+
Slave_IO_State |Waiting for master to send event |
Master_Host |192.168.20.161 |
Master_User |root |
Master_Port |3306 |
Connect_Retry |60 |
Master_Log_File |mysql-bin.004651 |
Read_Master_Log_Pos |300004719 |
Relay_Log_File |xxxx-relay-bin.002999 |
Relay_Log_Pos |300004932 |
Relay_Master_Log_File |mysql-bin.004651 |
Slave_IO_Running |Yes |
Slave_SQL_Running |Yes |
Replicate_Do_DB |alisaas |
Replicate_Ignore_DB |mysql,information_schema,performation_schema,sys |
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 |300004719 |
Relay_Log_Space |300005190 |
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 |161 |
Master_UUID |000fe6d4-25cd-21eb-a102-1111efa99c99 |
Master_Info_File |/sata01/data/mysql/master.info |
SQL_Delay |0 |
SQL_Remaining_Delay | |
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 | |
Auto_Position |0 |
Replicate_Rewrite_DB | |
Channel_Name | |
Master_TLS_Version | |
Slave_IO线程负责把主库的bin日志(Master_Log)内容,抄写到从库的中继日志上(Relay_Log)。
Slave_SQL线程负责把中继日志上的语句在从库上执行一遍。
Slave_IO线程相对比较简单,一般不容易出错。如果Slave_IO_Running显示为No,多为网络连接不上,权限不够等环境问题。
Slave_SQL线程相对容易出错,例如人为手动的在从库插入一条数据,造成主从不一致。但此时两个线程的状态仍然是正常的。等到主库也插入一条同样的数据时,通知从库做相同操作,从库会出现主键重复的错误。此时Slave_SQL_Running的状态会变为No,而Last_SQL_Error,Last_SQL_Error_Timestamp会记录错误的原因和发生时间。
Slave_SQL线程会停止后续的SQL语句执行,因为它意识到往后执行会导致错误修复的难度增加。但Slave_IO线程不会停止,会继续抄log的工作。所以中继log依然是最新的。
这时候Master_Log_File: mysql-bin.000002 和 Relay_Master_Log_File: mysql-bin.000001之间就产生了偏差。
以上面为例,主库的日志已经写到了 mysql-bin.000001,而从库依然停留在 mysql-bin.000002等待人工修复错误。
那么当错误修复后,只需用stop slave和start slave重启下同步。Slave_SQL线程会重新的尝试工作。
如果没有问题,那么Slave_SQL的状态会变回Yes。但此时主从并没有完全同步,需要一点时间。
若完全同步,可通过以下几条判断:
1. 首先 Master_Log_File 和 Relay_Master_Log_File 所指向的文件必须一致。
例如本案例中是mysql-bin.004651
2. Read_Master_Log_Pos = Exec_Master_Log_Pos 时,则表明 slave 和 master 处于完全同步的状态。例如本案例中是:300004719
Read_Master_Log_Pos 是io读到的位置,Exec_Master_Log_Pos 是sql执行到的位置。
1和2合并即:
Relay_Master_Log_File = Master_Log_File
Read_Master_Log_Pos = Exec_Master_Log_Pos
3. 此时,有几个字段值如下:
Slave_IO_State: Waiting for master to send event。意思是等待主库送事件过来
Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it。意思是从库已经读完所有的relay log,等待从库的IO线程继续更新。
1) The position, ON THE MASTER, from which the I/O thread is reading:
Master_Log_File/Read_Master_Log_Pos. -----相对于主库,从库读取主库的二进制日志的位置,是IO线程
2) The position, IN THE RELAY LOGS, at which the SQL thread is executing:
Relay_Log_File/Relay_Log_Pos ----相对于从库,是从库的sql线程执行到的位置
3) The position, ON THE MASTER, at which the SQL thread is executing:
Relay_Master_Log_File/Exec_Master_Log_Pos ----相对于主库,是从库的sql线程执行到的位置
show slave status\G中的Read_Master_Log_Pos和Relay_Log_Pos的(大小)关系_lovely可爱欧辰的博客-CSDN博客
执行以下3条命令。可以在navicat、dbeaver、或者cmd窗口,都行。
stop slave;
set GLOBAL SQL_SLAVE_SKIP_COUNTER=1;
start slave;
一次不行,多执行几次。或者修改数值1,改成2,或者3。前提是你知道怎么玩,不会玩的话,就用1,多执行几次。
Mysql主从错误之Slave_SQL_Running No - 简书
关于set global sql_slave_skip_counter=N 命令的解释_Mr. Sun_的博客-CSDN博客
Mysql主从同步时Slave_IO_Running:Connecting ; Slave_SQL_Running:Yes的情况故障排除_MegaBytes的博客-CSDN博客
Mysql主从同步时Slave_IO_Running:Connecting ; Slave_SQL_Running:Yes的情况故障排除_爽姐想退休的博客-CSDN博客
show slave status判断主从同步状态_chagaostu的博客-CSDN博客
mysql查看主从同步状态的方法_mysql_Full Stack Developme-华为云开发者联盟
MySQL :: MySQL 5.7 Reference Manual :: 16.1.2 Setting Up Binary Log File Position Based Replication
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文章到此已经结束,以下是紫薯布丁
show slave status;
stop slave;
set GLOBAL SQL_SLAVE_SKIP_COUNTER=1;
start slave;
Name |Value |
-----------------------------+------------------------------------------------------+
Slave_IO_State |Waiting for master to send event |
Master_Host |192.168.20.161 |
Master_User |root |
Master_Port |3306 |
Connect_Retry |60 |
Master_Log_File |mysql-bin.004651 |
Read_Master_Log_Pos |300004719 |
Relay_Log_File |xxxx-relay-bin.002999 |
Relay_Log_Pos |300004932 |
Relay_Master_Log_File |mysql-bin.004651 |
Slave_IO_Running |Yes |
Slave_SQL_Running |Yes |
Replicate_Do_DB |alisaas |
Replicate_Ignore_DB |mysql,information_schema,performation_schema,sys |
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 |300004719 |
Relay_Log_Space |300005190 |
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 |161 |
Master_UUID |000fe6d4-25cd-21eb-a102-1111efa99c99 |
Master_Info_File |/sata01/data/mysql/master.info |
SQL_Delay |0 |
SQL_Remaining_Delay | |
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 | |
Auto_Position |0 |
Replicate_Rewrite_DB | |
Channel_Name | |
Master_TLS_Version | |