PHP Load Process

degauss

I've tried searching around for information on how PHP parses and renders itself.

Basically, I'm writing a bunch of scripts that rely on a core file. The core itself is quite large (around 20k), but the scripts that reference it don't often utilise the entire contents of the core.

Inside the core are functions that are never called inside the core, and a bunch of constants and globals that I call from the referencing scripts.

So I guess in a nutshell, I want to know if when I call require, does PHP read the entire file? Or does it only read the bits it needs? I realise that last sentence makes me sound like I have trouble putting legos together, but I would just like to know how PHP goes about it duty 🙂

_RL_Ian

From my experience (and don't quote me on this), it reads the entire file and puts the whole thing in memory before it parses it. This is especially important in class files, where a function at the top of the file may rely on a function at the bottom.

degauss

Yeah... I was kinda afraid of that.

So for optimal loadtimes, do you think it would a be a good idea to chunk up my core file into seperate files, and have a main core file that requires/includes the functionality from the sub-core files on a as-needed basis?

superwormy

You also have to consider that everytime you need to go get another file to be parsed ( require, or include ) you have a hit to the filesystem, which slows things down.

In any case... a 20kb PHP file is actually pretty damn small. Some of the pages on our site include 10 or 15 20kb files and the page still gets built in less than 1/10 of a second.

The general rule with programming is:
Don't optimize unless you have to
Don't optimize until your program is finished and complete
Look for the 10% of the code that takes up 90% of the CPU time, and focus on that

Are your pages loading very slowly? Have you benchmarked them? Are you sure the 20kb file is the problem?

Weedpacket

If there is some visible distinction between which parts of the core are used when (and if some parts of the site don't use core functions then that lessens the justification for calling them "core" in the first place, so that might give you an idea about how to partition it) then certainly putting them in separate files and including only the ones you need would be a way to go.

But 20kB isn't that much.