MySql data replication: How to achieve timely replication of data across multiple distributed MySQL nodes

As a powerful relational database, MySQL has been widely used in many application scenarios. In some large application systems, MySQL data needs to be replicated to achieve data synchronization between multiple nodes, thereby improving data availability and ensuring high system availability. This article will introduce how to use MySQL's data replication technology to achieve timely replication of data across multiple distributed MySQL nodes.

1. The principle of MySQL data replication

MySQL data replication refers to the process of copying data in one MySQL instance to another MySQL instance. In the data replication architecture of MySQL, there are two roles, namely the master database and the slave database.

Main library: The main library is the node responsible for write operations, that is, the source node of the data. The binlog component is configured on the main database, which is responsible for recording all SQL statements that modify data.

Slave library: The slave library is the node responsible for the read operation, that is, the copy node of the data. The slave library updates the local data by reading the binlog log file of the master library to achieve data synchronization.

The workflow of MySQL replication is as follows:

1. When the main library performs a write operation, it records the modified SQL statement into the binlog log file.

2. Start the I/O thread from the library, pull the binlog log file from the main library and save it locally.

3. Start the SQL thread from the database, and replay the SQL statements stored in the local binlog log file on the slave database for execution, thereby achieving data synchronization.

2. Implementation of MySQL data replication

In MySQL data replication, the following configurations are required:

1. Main database configuration

In the main database In the library, you need to enable the binlog component, enable row mode, and record the SQL statements of all operations.

Open the my.cnf configuration file and add the following configuration items under the [mysqld] node:

log-bin=mysql-bin
binlog-format=ROW

Among them, the log-bin configuration item specifies in which file the binlog log is saved, binlog-format The configuration item specifies the use of ROW mode to record binlog logs.

2. Slave library configuration

In the slave library, you need to copy the main library, and you need to configure the following:

Open the my.cnf configuration file, and go to [mysqld ]Add the following configuration under the node:

server-id=101  #指定从库的唯一标识，要求唯一
replicate-do-db=test_db  #指定要复制的数据库
log-slave-updates   #记录从库上执行的SQL语句写入binlog文件

Among them, the server-id configuration item specifies the unique identifier of the slave database, the replicate-do-db configuration item specifies the database to be replicated, and the log-slave-updates configuration item specifies the record. SQL statements executed from the library are written to the binlog file.

Restart the MySQL service. When the slave library starts, it will automatically pull the binlog log file from the main library and replay the SQL statement on itself to achieve data synchronization.

3. High availability of MySQL data replication

MySQL data replication can provide high availability, but at the same time, data reliability and consistency need to be ensured. During the MySQL data replication process, the main database may be down, the slave database may not be updated in time, etc., resulting in inconsistency between the master and slave data.

In order to ensure the high availability of MySQL data replication, we can adopt the following measures:

1. Multi-master replication: configure binlog logs in multiple master libraries, and slave libraries from multiple master libraries Pull the binlog log from the database to copy the data. In this way, even if one main database goes down, other main databases can still provide services to ensure high availability of the system.

2. Master-slave switching: When the main database goes down, it needs to quickly switch to other main databases to provide services. You can switch between the master database and the slave database through the database agent to achieve faster master-slave switching operations.

3. Separation of reading and writing: In order to reduce the pressure on the main library, read operations can be divided into multiple slave libraries. At this time, attention needs to be paid to the timeliness of data updates from the database to ensure data reliability.

Summary:

MySQL data replication can realize data synchronization of distributed multiple MySQL nodes, improving data availability and system high availability. Through reasonable configuration and high availability measures, the reliability and consistency of data can be guaranteed to meet the needs of large-scale application systems.

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