MySQL implements data table replication and synchronization

As the amount of data continues to increase, database backup and synchronization become more and more important. As a popular relational database management system, MySQL provides a variety of methods to achieve replication and synchronization of data tables.

MySQL's data replication mechanism can be used for real-time data backup, disaster recovery, read-write separation, etc., thereby improving the availability and flexibility of the database system. This article introduces MySQL's methods of replicating and synchronizing data tables, including replication-based, master-slave replication, and multi-master replication.

1. Replication-based data synchronization method first appeared in MySQL version 3.23 and is called "replication". This method is to completely copy the data of one MySQL server to one or more MySQL servers to achieve data high availability, read-write separation, backup and migration and other functions.

The basic principle of replication is to send the transaction log (binary log) on ​​a certain MySQL server to other servers, and other servers copy the database of the server by parsing the log. Replication is mainly divided into two methods: synchronous replication and asynchronous replication. Synchronous replication means that the transaction is submitted only after both the master server and the slave server confirm that the transaction has been processed; asynchronous replication means that after the master server completes a transaction, it will It writes to a binary log file and returns immediately, allowing other servers to asynchronously read the contents of the file for data replication.

The replication-based synchronization method has the following advantages:

1. Data replication is fast.

2. The data between the master server and the slave server is almost real-time, which can well support high availability.

3. Supports read-write separation and load sharing from the server.

2. Master-slave replication

Master-slave replication is one of the most mainstream data synchronization methods in MySQL and is also a type of replication function. In master-slave replication, the master server is responsible for processing all write operations and writing them all to the binary log file; the slave server copies the binary log from the master server and applies the update operations to its own database. The separation of reading and writing through master-slave replication can solve the problem of data unavailability caused by single points of failure.

Features of master-slave replication:

1. The master server handles write operations and the slave server handles read operations, which can effectively share the workload.

2. When the network between the slave server and the master server fails, the slave server can continue to provide read services, thus avoiding service unavailability caused by network failures.

3. It has no impact on the processing speed of the main server, because the main server only needs to write the update operation to the bin-log and does not have to wait for the slave server to respond.

Disadvantages of master-slave replication:

1. For write-intensive applications, it will increase the load on the master server, so the performance of master-slave replication needs to be considered.

2. If an incorrect operation occurs on the master server, it may cause the same error on the slave server.

3. Multi-master replication

Multi-master replication is an advanced replication mode of MySQL and is also a type of replication function. In the multi-master replication mode, multiple MySQL servers can serve as master servers for write operations and as slave servers to copy data from other master servers, so that synchronization between multiple MySQL servers can be achieved.

Features of multi-master replication:

1. All master servers can write update operations, and each master server can write update operations to their own bin-log file , so that they can copy each other's data.

2. In the multi-master replication mode, data synchronization can be carried out across each other, so network reliability issues will not affect the availability of the system.

Disadvantages of multi-master replication:

1. Update operations need to be performed on multiple servers, which requires a large load and requires high server performance.

2. If an incorrect operation occurs on one master server, it may cause the same error on other master servers.

Summary:

MySQL provides a variety of data replication and synchronization methods to solve problems such as data backup, read-write separation, and high availability. It is very important to choose a suitable replication solution based on your actual needs. Through the introduction of MySQL's three data synchronization methods, namely replication, master-slave replication and multi-master replication, I believe readers can better understand the similarities and differences between them as well as their respective advantages and disadvantages, and provide information for realizing their own data backup and synchronization needs. Suitable selection and guidance.

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