Takeaways
Testing is the best way to maintain application performance after optimization. Let’s summarize what it takes to do that.
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Write performance tests—special kinds of integration tests that benchmark your code, keep results, and then assert performance by comparing current and previous benchmarks.
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Make sure your performance tests get the measurements and comparisons right. Use the framework we wrote in this chapter to create your own performance tests.
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When performance testing Rails, don’t forget about database performance. Make sure you create enough data for performance tests, and check how many queries your requests run.
Congratulations! Now you know everything you need to know to optimize your Ruby code, measure optimization result, and ensure that your optimization persists.
But our quest for faster Ruby applications is not over yet. To optimize, we thought of our code as of a white box that we can dissect and improve. As you might guess, another approach would be to think of it as of a black box, and optimize the way we run the code by speeding up its dependencies and the whole execution environment. So let’s do just that.