aws-sdk-java-v2 VS Hey

In this article we'll now add another dimension to our measurements : the choice of HTTP Client implementation. This is also interesting, because starting from AWS SDK for Java version 2.22 AWS added support for their own implementation of the synchronous CRT HTTP Client. The asynchronous CRT HTTP client has been generally available since February 2023. In this article we'll explore synchronous HTTP clients first and leave asynchronous ones for the next article.

The updates could be parsed from the github repo's CHANGELOG files (ex: javascript, java, python). I'm picturing an RSS feed generated for a specific language and module (ex: python s3, javascript s3, java sqs)

Meanwhile the [SDK doesn't provide samples or an API for USER_SRP_AUTH AuthFlow](https://github.com/aws/aws-sdk-java-v2/issues/2851). (I don't think that's the right choice, anyway, because if I'm right I'd have to register my user in my new app, and I don't want to do that).

Bonus: AWS SDK for Java v2 - this one I'm not sure of their reasons, but this request to add nullability annotations was filed 4.5 years ago, and there has been virtually no movement or feedback on it, so I can only speculate about their reasons for not fixing this.

If you think its a genuine bug in the API or the client somehow I think opening an issue in the github repo for the sdk might be a good place to start https://github.com/aws/aws-sdk-java-v2/issues .

Should be possible to just issue a GetObject with a range for the initial request skipping a head request. See here for caveats about how the Content Range data is returned in the response header: https://github.com/aws/aws-sdk-java-v2/issues/1209

V2 AWS SDK for Dynamo DB, SNS, and SQS

DynamoDB mapper AWS SDK v2 readme

The results of the experiment below were based on reproducing approximately 100 cold starts for the duration of our experiment which ran for approximately 1 hour. For it (and all experiments from my previous articles) I used the load test tool hey, but you can use whatever tool you want, like Serverless-artillery or Postman

The results of the experiment to retrieve the existing product from the database by its id see GetProductByIdViaAuroraServerlessV2DataApiHandler with Lambda function with 1024 MB memory setting were based on reproducing more than 100 cold and approximately 10.000 warm starts with experiment which ran for approximately 1 hour. For it (and experiments from my previous article) I used the load test tool hey, but you can use whatever tool you want, like Serverless-artillery or Postman. We won't enable SnapStart on the Lambda function first.

The results of the experiment below were based on reproducing more than 100 cold and approximately 100.000 warm starts with experiment which ran for approximately 1 hour. For it (and experiments from my previous article) I used the load test tool hey, but you can use whatever tool you want, like Serverless-artillery or Postman. I ran all these experiments for all 3 scenarios using 2 different compilation options in template.yaml each:

In our experiment we'll re-use the application introduced in part 9 for this. There are basically 2 Lambda functions which both respond to the API Gateway requests and retrieve product by id received from the API Gateway from DynamoDB. One Lambda function GetProductByIdWithPureJava21Lambda can be used with and without SnapStart and the second one GetProductByIdWithPureJava21LambdaAndPriming uses SnapStart and DynamoDB request invocation priming. We'll measure cold and warm starts using the following memory settings in MBs : 256, 512, 768, 1024, 1536 and 2048. I also put the cold starts measured in the part 12 into the tables to see both cold and warm starts in one place. The results of the experiment below were based on reproducing more than 100 cold and approximately 100.000 warm starts for the duration of our experiment which ran for approximately 1 hour. Here is the code for the sample application. For it (and experiments from my previous article) I used the load test tool hey, but you can use whatever tool you want, like Serverless-artillery or Postman. Abbreviation c is for the cold start and w is for the warm start.

Por último, podemos executar os testes de carga usando hey.

For running our experiments to provoke anomalies we'll use the stress test tool. You can use the tool of your choice (like Gatling, JMeter, Fiddler or Artillery), I personally prefer to use the tool hey as it is easy to use and similar to curl. On Linux this tool can be installed by executing

Hey: is a fast HTTP load testing tool used to test web applications and APIs. It provides a CLI (command-line interface) and supports concurrent requests.

The client and server nodes are CentOS7.9/X86_64. If the HTTP POST requests were sent directly to the server with hey -c 1, there are about 0.2% of cases that may timeout. If the HTTP POST requests were sent through an NGINX proxy on the client node, there are about 20% of cases will timeout. I've confirmed that only one backend node has this problem. All other nodes are 100% succeeded even with higher throughput.

64 concurrent requests isn't a lot. Modern web apps can typically handle much more than that (depending on what the request does, of course). Try it yourself with a load tester like https://github.com/rakyll/hey against a Go HTTP server, for example the one I've built in https://www.golang.dk/articles/go-and-sqlite-in-the-cloud