ApsaraDB RDS:What are database proxies?

A database proxy serves as a network proxy that resides between your database system and your application and receives all requests from your application. You can connect to your RDS instance by using a database proxy endpoint to use various capabilities of the database proxy feature. This simplifies the connection management of the RDS instance. The database proxy feature is easy to use and maintain and delivers high availability and high performance.

Scenarios

• The primary RDS instance is heavily loaded due to a large number of requests that are encapsulated in transactions.

• The primary RDS instance is heavily loaded due to an excessively large number of connections.

• Most of your workloads require short-lived connections.

• Read/write splitting is required.

• Read-only workloads and workloads that need to be isolated.

• The capability to prevent transient connections that are caused by O&M operations such as switchovers is required.

  Note

  For example, your database system consists of one primary RDS instance and four read-only RDS instances, and you have two applications, Application A and Application B. Application A initiates only read requests, and Application B initiates both read and write requests. You want to connect Application A and Application B to the database system. You can bind two read-only RDS instances to Proxy Terminal A that has the Read-only attribute to process the requests from Application A and bind the primary RDS instance and the other two read-only RDS instances to Proxy Terminal B that has the Read/Write attribute to process the requests from Application B. This way, Application A and Application B are physically isolated from each other in your database system.

Terms

• database proxy endpoint (formerly known as proxy terminal)

  Database proxy endpoints are the core of database proxies. You can configure connection settings for a database proxy endpoint based on your business requirements, the prefix of the database proxy endpoint, and the port that is associated with the database proxy endpoint. If you use a database proxy endpoint to connect to an RDS instance, you can use the advanced capabilities of the database proxy feature.

  Each RDS instance with the database proxy feature enabled supports up to seven database proxy endpoints. You can apply for one internal endpoint and one public endpoint for each database proxy endpoint. You can also configure connection settings for each database proxy endpoint to meet different business requirements and improve service flexibility. For more information, see Configure the connection settings for a database proxy endpoint and Database connection.

• read/write splitting

  Read/write splitting indicates that database proxy endpoints can be used to automatically forward read and write requests.

  If your database system receives a large number of read requests and a small number of write requests, the primary RDS instance may fail to efficiently process read requests and your workloads may be interrupted. The read/write splitting feature allows the system to forward write requests to the primary RDS instance and read requests to the read-only RDS instances. This reduces the loads on the primary RDS instance. For more information, see What is read/write splitting?

• transaction splitting

  The transaction splitting feature is automatically enabled for a database proxy. This feature allows the system to forward the read requests prior to write operations in a transaction to the read-only RDS instances of your database system. This reduces the loads on the primary RDS instance. For more information, see Transaction splitting.

• connection pooling

  The connection pooling feature effectively solves the problem of heavy instance loads caused by frequent new connections or excessive short-lived connections such as short-lived connections over PHP. For more information, see Set the connection pool type.

• SSL encryption

  The SSL encryption feature can be enabled for a database proxy endpoint. This feature protects the data that is destined for a database proxy endpoint. For more information, see Configure SSL encryption for a dedicated proxy endpoint.

Types of database proxies

ApsaraDB RDS for MySQL provides general-purpose and dedicated database proxies.

• General-purpose: Database proxies share physical CPU resources and are provided free of charge. This type of database proxy is cost-effective.

• Dedicated: Database proxies exclusively occupy the allocated physical CPU resources and are charged based on the pay-as-you-go billing method. This type of database proxy delivers stable performance.

The following table describes the differences between the two types of database proxies.

Usage notes

For more information, see Usage notes of database proxies.

Billing

For more information, see Billing rules for database proxies.

References

For more information, see Use the database proxy feature.