When to use Static Methods for Speed?

[Torite]

I am having trouble understanding how to use static methods and properties well. I don’t understand the features and limitations of static methods and properties vs non-static methods and properties.

http://php.net/manual/en/language.oop5.static.php

I understand that a static method can be called like this:

myClass::staticMethod();

instead of this:

$myClass = new myClass();
$myClass->method();

But other than the static method call being 1 line shorter, what is the point? What mechanics are different? I am trying to understand this primarily for overhead purposes.

The particular classes I am working on are meant to be as fast as possible, as they are stats related and used everywhere in the app I am working on. I have heard php static methods are faster than non-static methods, so I decided to use them here. That is really the ONLY reason I am using static methods, as a few milliseconds can actually add up to non-trivial page load time increases due to the amount of stat collection done. (10x-50x multiplication or more per millisecond. And before you might ask, I cannot use a lower-level language, this isn’t a case of premature optimization, and I don’t care about testing for these classes.)

1. Does it make sense to use a static method if the class has a constructor?
2. Does it make sense to use a static method if that method calls another static method within it? (And what if the method is in a parent class, not the same class?)
3. Does it make sense to use a static method if that method calls a non-static method within it? (And what if the method is in a parent class, not the same class?)

Pretend I have 3 classes. Class A is the parent class, and class B and C are children of class A and make use of A’s methods. Class B has a constructor, and in that constructor, constructs class A. Class C has no constructor of its own.

If I call a static method in class C, and this method does not call any other method, is class A loaded into memory (because it is the parent)? What if I call a static method in class C that in turn does call a static method in Class A?

My own benchmarking has yielded strange results that seem to show that static methods are slower, or equivalent to, non-static methods. This is sort of like the results here: http://stackoverflow.com/questions/1472721/performance-of-static-methods-vs-functions

But I am not confident that my benchmarks are testing the right things because I am not sure of the use-cases for static methods and how they are loaded behind the scenes. It’d be nice if I could make the case from first-principles that static methods should be slower or faster for my use-case.

[s_molinari]

@Torite

Pretend I have 3 classes. Class A is the parent class, and class B and C are children of class A and make use of A’s methods. Class B has a constructor, and in that constructor, constructs class A. Class C has no constructor of its own.

Could you expand on this example a bit more, like what each of the classes should be representing or doing? I have a feeling you (or even myself) might not have the big picture, when it comes to inheritance or polymorphism.

In general (and I think I also just answered the same question in another thread) static methods go against OOP. They are basically a way to call methods of classes procedurally. They also make classes that call on static methods hard to test. Edit: and these are things I’ve learned in theory, not in practice.

Scott

[djsmithme]

If your going for all out speed then technically doing this procedurally would be quicker.

Creating a OOP wrapper and hiding a bunch of methods behind it is no better afterall, you could just stick an array inside a namespace. Given that the chances are these classes have already been autoloaded into memory there is normally very little benefit calling it statically, also you have to consider whats happening behind the scenes, what is php doing when it’s calling them?

Then you have to remember to call them statically ← this is the kicker for me at least.