Premature optimization is dangerous

Amit Merchant · December 18, 2019

Working with PHP, it would be pretty obvious you’d be worried about the performance of your application. And because of this anxiety, you start to optimize trivial things such as replacing double quotes(“) to single quotes(‘), use echo instead of print_r, or using static methods in order to gain those little performance gains during the initial few days of your application development itself. Optimizing these thigs is good and all.

But think about it. If your application is wrongly designed in the first place, these tips won’t help you much. The phenomena is called as “Premature optimization” where you start to optimizing things before even measuring your application first and get to know what’s the root cause of the performance bottleneck.

As a wise man rightly said once,

“Premature optimization is the root of all evil” ~ Donald Knuth

So the point here is, it really doesn’t matter when you make your code run 0.15ms faster when a single SQL query in your application takes a good 80ms of time. Micro optimizations are the last resort when you’ve got the perfect application design and still need more performance from certain modules/functions.

Premature optimizations comes with the following drawbacks:

  • Your development time gets increased.
  • The time required to test the application gets increased.
  • You invest more time fixing bugs that otherwise wouldn’t be there.

If we talk specifically about PHP, you could use the tool like XDebug which can determine which areas of your application are eating up your application’s performance. By the end of profiling, you’d be surprised to find that your application is taking more time executing database queries, which, let’s say, is 100ms than the trivial str_replace calls which take only 0.5ms. So, it’s better to optimize your queries and application first than to optimize less important stuff such as replacing function calls. Sure, these things are equally important. There’s no denying about it, but it’s more important to get the core things right. You don’t need to focus so much on the low-level performance optimizations.

In order to avoid premature optimizations, this is what you can do. In which, you can design your application first, then code your application according to the specified design and then profile/benchmark the resulting code to see which parts should be optimized. A simple and elegant design is often easier to optimize at this stage, and profiling may reveal unexpected performance problems that would not have been addressed by premature optimization. And if you still have time left, you’d go for the micro-optimizations. That is how you’d prevent yourself getting into premature optimization.

In closing

Optimizations are important but as a developer, you have to balance things out. So, taking care of the application design along with the profiling it time-to-time can go a long way and in the end, you might end up with an application that wouldn’t require a whole lot of optimizations. Which of course saves time and energy altogether.

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Hi there! I'm Amit. I write articles about all things web development. If you like what I write, buy me a coffee. I'd highly appreciate that. Cheers!

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