PHP中的高性能OOP

Question

pretty much a question in regards to performance when working with objects. Currently using ZF2 and trying to replicate things in my game.

I have a map with terrains on them. Each terrain has a name and a description.

The description could be something between 200-500 words long. If I'm building a map hundreds, thousands of these objects then in terms of performance, where would I be better off putting the description.

If it was a property like so:

public $description = 'Blah blah blah.... 500 chars long';

Would it create say.... 1,000 x 500 byte descriptions when I'm looping through and putting these objects onto a map or does PHP optimise and say, the description won't be created until its requested through $obj->description . If that's the case then if it was to be in method like.....

public getDescription () { 
    return "Blah blah blah.... 500 chars long"; 
} 

then is this using less memory because it doesn't add to memory on object creation but only requests it on calling it?

Aaand if none of the above is any good... I guess I could put them into a seperate view file so then I can use HTML and do anything fancy as well. I guess this is the ultimate solution but I'm looking more into how PHP handles memory... anywhere I can find any information?

Thanks, Dom

Answer 1

Is the description the same between objects of the same class? use static attribute for common values between objects of the same class.

Answer 2

I cannot say for sure, but I don't think there is a difference in what you proposed, because the string will have to exist in memory because it exists in the code; it just won't be assigned to a variable until the function is called. (If, however, you call the same function 100 times for 100 different variables, then it will be adding space in memory, and you may be able to save some of that space via a function call; but beware this may take more processing time).

You may be interested in the some documentation on memory management in PHP

Here is an interesting book

A couple quick thoughts:

• Performance is more than RAM; it's processing time. And simply put, making a function call adds processing time (if you have any Assembly Language training, you know it takes a few processor cycles). This is relatively moot for modern programmers, but C functions like malloc take a really long time to run, so making fewer calls to allocate memory can be better.
• Know where your data will be coming from and going (if it's static data, try the static keyword; if it changes rapidly, look into databases like MySQL, or how to parse the data in XML or JSON.

Answer 3

These are two ways to avoid having thousands of descriptions in your PHP memory at the same time:

If there are a (limited) number of different stereotypes sharing the same description, you can use integer constants to identify a stereotype, and create a function (typically static member) to translate the constant to the description when you need the description.

If each object has a different description, but is taken from some external data source (ie not PHP memory) you can also consider retrieving the description from that data source at the moment you really need it.

Additionally, if you have to load the same descriptions in memory on each page request, you can also consider using some type of cache, such as Memcache or Redis and retrieve relevant descriptions when needed.

Answer 4

查看flyweight和代理模式。