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MySQL's master-slave replication and read-write separation are important technical means to improve database performance and availability.

 

Master-slave replication:

 

The main purpose of master-slave replication is to achieve redundant backup of data, improve data availability, and separate the read and write of the database to improve performance.

 

Master server configuration:

 

1. Enable binary log: record all modification operations on the database.

2. Configure a unique server ID: used to identify the master and slave servers.

 

Slave server configuration:

 

1. Also configure a unique server ID, which cannot be the same as the primary server.

2. Specify the connection information for the primary server, including host name, port, username, and password.

 

The specific process of master-slave replication:

 

1. The I/O thread of the slave server connects to the master server and requests the master server to start sending binary logs from the specified position.

2. After receiving the request, the master server starts a thread to send the contents of the binary log to the slave server.

3. Receive the binary log data from the server's I/O thread and write it to the local relay log.

4. Read the contents of the relay log from the SQL thread of the server and replay the operations in the log in the local database to achieve data synchronization.

 

Copy Mode:

 

1. Statement-based replication: The master server records the executed SQL statements in the binary log, and the slave server replays these statements. This method is simple, but may cause inconsistencies for some non-deterministic statements.

2. Row-based replication: records changes to data rows, which is more accurate but generates a larger amount of logs.

3. Hybrid replication: Automatically select statement-based or row-based replication mode according to the situation.

 

Delay in master-slave replication:

Due to factors such as network latency and slave server performance, there may be a certain delay between the slave server data and the master server data.

 

Read-write separation:

 

Read-write separation is implemented on the basis of master-slave replication, where database read operations are assigned to slave servers and write operations are assigned to master servers.

 

Ways to achieve read-write separation:

 

1. Manual configuration in the application: Send requests to different servers depending on the type of operation (read or write).

2. Use middleware: such as MyCat, ProxySQL, etc., which can automatically route traffic to the master server or slave server based on the request type.

 

Advantages of read-write separation:

 

1. Improve performance: Write operations are concentrated on the master server, and read operations are distributed to multiple slave servers, improving the system's concurrent processing capabilities.

2. Load balancing: Rationally distribute read operations to different slave servers to avoid excessive load on a single server.

 

Challenges of read-write separation:

 

1. Data consistency: Due to delays in slave servers, non-latest data may be read.

2. Failover: When the master server fails, write operations need to be switched to the new master server in a timely manner, while ensuring that the slave server can keep pace with the new master server.

 

In summary, MySQL's master-slave replication and read-write separation is a complex but effective database optimization solution, which needs to be carefully designed and configured according to actual business needs and system architecture to give full play to its advantages while dealing with possible problems.