


Step 2: Configure the standby machine
Let’s continue. Stop the MySQL service program on the standby machine, and move the database directory copied from the host machine to the data directory on the standby machine. Please make sure to change the owner and group of the directory to the corresponding values of the MySQL user, and modify the file mode to 660 (only readable and writable for the owner and group), and the directory itself to 770 (only for the owner and group) readable, writable and executable).
Continue. Start the MySQL service program on the backup machine and confirm that MySQL is working properly. Run a few select queries (do not update or insert queries) to see if the data snapshot obtained in the first step is successful. Then, shut down the MySQL service program after the test is successful.
Configure the host that needs to be accessed on the standby machine to receive changes from the host. So you need to edit the "my.cnf" file on the server and add the following lines in the [mysqld] section:
master-host=10.1.1.1
master-user=replicate
master-password=password
After starting the standby service program, the standby service program will check the host specified in the "my.cnf" file to see if there are any changes, and merge these changes into its own database. The standby machine maintains the host's update records, which are received from the host's "master.info" file. The status of the standby thread can be seen through the sql command "SHOW SLAVE-STATUS". If an error occurs while processing the binary log on the standby machine, it will cause the standby machine thread to exit and generate a message in the *.err log file. The error can then be corrected and the standby thread can be restarted using the SQL statement "SLAVE START". The thread will continue processing from where host binary log processing left off.
At this point, the data changes that occurred on the main machine should have been copied to the standby machine. To test it, you can insert or update a record on the main machine and select this record on the standby machine.
Now we have this master-slave relationship from machine A to machine B, which allows us to redirect all queries to machine B when machine A may crash, but when machine A recovers , we have no way to restore the changes to machine A. To solve this problem, we create a master-slave relationship from machine B to machine A.

mysql的msi与zip版本的区别:1、zip包含的安装程序是一种主动安装,而msi包含的是被installer所用的安装文件以提交请求的方式安装;2、zip是一种数据压缩和文档存储的文件格式,msi是微软格式的安装包。

在mysql中,可以利用char()和REPLACE()函数来替换换行符;REPLACE()函数可以用新字符串替换列中的换行符,而换行符可使用“char(13)”来表示,语法为“replace(字段名,char(13),'新字符串') ”。

转换方法:1、利用cast函数,语法“select * from 表名 order by cast(字段名 as SIGNED)”;2、利用“select * from 表名 order by CONVERT(字段名,SIGNED)”语句。

本篇文章给大家带来了关于mysql的相关知识,其中主要介绍了关于MySQL复制技术的相关问题,包括了异步复制、半同步复制等等内容,下面一起来看一下,希望对大家有帮助。

在mysql中,可以利用REGEXP运算符判断数据是否是数字类型,语法为“String REGEXP '[^0-9.]'”;该运算符是正则表达式的缩写,若数据字符中含有数字时,返回的结果是true,反之返回的结果是false。

本篇文章给大家带来了关于mysql的相关知识,其中主要介绍了mysql高级篇的一些问题,包括了索引是什么、索引底层实现等等问题,下面一起来看一下,希望对大家有帮助。

在mysql中,是否需要commit取决于存储引擎:1、若是不支持事务的存储引擎,如myisam,则不需要使用commit;2、若是支持事务的存储引擎,如innodb,则需要知道事务是否自动提交,因此需要使用commit。

“mysql-connector”是mysql官方提供的驱动器,可以用于连接使用mysql;可利用“pip install mysql-connector”命令进行安装,利用“import mysql.connector”测试是否安装成功。


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