Overview

The read/write separation is designed for the database read/write scenario with massive read requests. Allocate the read traffic requests to the master instance and read-only instance that are bound to proxy instance according to weight ratio by creating multiple read-only instances for the master instance. The read/write separation feature grants the master instance elastic read ability expansion to increase the users’ data throughput, and alleviate the master instance’s pressure in handling massive read requests.

Read-only instance

If you want to realize Read and Write Separation, you need to create a read-only instance for the master instance after the creation of the current master instance. Master instance and read-only instance have an independent connection address, which may be automatically configured by the application, leading to the separation of the data reading and writing operations. For detailed creation and management of read-only instance, see [Read-only Instance]https://cloud.baidu.com/doc/RDS/s/Jjzyc9f0r.

Proxy instance

After the read-only instance is enabled, you may create a proxy instance to set and manage the master instance and read-only instance’s read traffic weight, and in turn, realize the effective distribution of the read traffic. You may also enable the read-only instance’s read traffic loading feature in your service code, and allocate the read traffic to designated read-only instance simultaneously. For detailed enabling and management of proxy instance, see Proxy Instance.

Relation between master instance and read-only instance/proxy Instance

See figure below for relations among master instance, read-only instance, and proxy Instance: Master instance is in charge of the read/write requests, read-only instance only in charge of the read request, and proxy instance sets and manages read traffic weight ratio of master instance and read-only instance. You may create a read-only instance and proxy instance for the master instance on the “Master Instance Details” page after the creation of the current master instance.