What is the purpose of database proxy in AWS Lambda?

Question

I'm working on AWS Lambda and I have integrated the SQL server using node.js. Here is its example. Now, my question is, what is the database proxy in AWS lambda and how I can get benefit from this?

Thanks

Answer 1

you have probably already read this:

RDS Proxy helps you manage a large number of connections from Lambda to an RDS database by establishing a warm connection pool to the database. Your Lambda functions can scale to meet your needs and use the RDS Proxy to serve multiple concurrent application requests. This reduces the CPU and Memory requirements for your database, and eliminates the need for connection management logic in your code.

If you have a single concurrent Lambda, then there is no benefit. However, many applications take advantage of the ability of Lambda to scale to 1000s or 10,000s of concurrent requests. Since Lambdas do not preserve state, these means establishment/maintenance of a DB connection for each of those 10,000s. This is inefficient, a pain to code, and can exceed the DBs ability to scale

So... from that same blog

Your Lambda functions interact with RDS Proxy instead of your database instance. It handles the connection pooling necessary for scaling many simultaneous connections created by concurrent Lambda functions. This allows your Lambda applications to reuse existing connections, rather than creating new connections for every function invocation.

The RDS Proxy scales automatically so that your database instance needs less memory and CPU resources for connection management. It also uses warm connection pools to increase performance. With RDS Proxy, you no longer need code that handles cleaning up idle connections and managing connection pools. Your function code is cleaner, simpler, and easier to maintain.

Answer 2

The RDS proxy benefits will be clear in 2 scenarios:

• High-concurrency lambdas to limit number of opened connections to the database. RDS Proxy will have limited connections opened regardless of how many concurrent lambdas exist

• Low-latency applications to avoid DB connection time when lambda is just starting. RDS Proxy will keep a pool of warm connections to the database.

Answer 3

The scalable Lambda Function is a single process unlike application server which maintains a connection pool and handle the connections efficiently, Example : EJB, Hibernate, Node frameworks. To handle this drawback in Lambda a database proxy was introduced which sits between Lambda and Database. Lambda->Proxy->Database.It enables a Lambda to reach high concurrency levels without exhausting database connections.Ideally in RDS or Traditional Mysql Hosting the connections are limited and scarce resource.

If you want to practically experience the Lamdba connection issue then do a load testing with free tier RDS and lambda.

It's also one way of making money for AWS.Example $0.015 per RDS Proxy vCPU hour 1,440 Hrs. $21.60.Refer website for latest price.

Is it Database proxy Production ready? I don't know.

Answer 4

As explained by Mohammed,the RDS proxy is like a connection pool.

The RDS proxy is a Lamdba Service feature allowing to share DB sessions between lambda functions, and their concurrent instantiations. So it allows to minimize the number of DB sessions. Without the RDS Proxy, you would have 1 DB session for each concurrent execution of your lambda functions. Thanks to a connection pool, you can have for instance 20 concurrent executions of your lambda-functions sharing the same DB session.

RDS proxy is especially useful for transactional apps, as executions of your lambdas release quickly their connection to the DB, and therefore a DB session can be shared across many lambda functions and executions.