Principle and process of MySQL master-slave replication

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MySQL What is master-slave replication ？

Make sure the primary server （Master） And from the （ To prepare Slave） Data consistency , Want to Master After data modification ,（ Under certain rules ）Slave Will Master Synchronize the data in .

MySQL What problem does master-slave replication solve ？

1. High availability and stability

When Master When the node goes down , You can specify one Slave act as Master,（ When the Master Downtime during data operation , May lead to Slave Machine data inconsistency ）

2. Load balancing

Can be read-write separation , such as Master Mainly used for write operation , The read operation is left to Slave, As the demand for query is greater , Use multiple standby servers for reading .

3. Business modularity

Create the database index for different business scenarios and select according to the business MySQL Storage engine , Different slave Different indexing and storage engines can be set according to different requirements

MySQL Master slave replication process

1. Master The master library will write the changed data to ,（ adopt binlog Threads ）binlog Binary log , Execute sequence to record binary log . After logging binary logs , The main database tells the storage engine that the transaction can be committed .
2. Slave Will start a IO Threads ,IO Threads will read in sequence Master Binary log in , And write it to the relay log (relay log).
3. Slave The information in the relay log of is passed through SQL Threads The playback , Execute... From the library , To update the data .

Please correct me if there is any mistake