PHP and memory...

[ajlisowski]

I am in the midst of developing a web application and despite having a decent amount of experience in web development, I never really stopped and gave a ton of thought to memory when it comes to my php scripts. However, with this project I am using zend framework and it is a decent memory hog. So I have some questions...

 

I am monitoring my memory use for a typical call to my site and it appears as though its somewhere around 20MB. This seems like a ton and I am actively looking for ways to decrease it. One thing I noticed is that when I call zend's date class for the first time, my memory usage shoots up 3MB. However it is pretty much untouched for other instances of this class.

 

So if I do

 

echo(memory_get_usage());
        echo('<br />');
        $this->last_login=Zend_Date::now();
        echo(memory_get_usage());
        echo('<br />');
        $this->last_active=Zend_Date::now();
        echo(memory_get_usage());
        echo('<br />');

 

The result is

9136448

12812408

12814496

 

So the jump is with that first call.

 

My question is, if two users are accessing the site at the same time, will they both experience that 3MB memory use? Or will the server have that class in memory so it only uses 3MB once?

 

Basically, if a call to the site uses 20MB of memory, will it be 20MB * the number of users. Or will the server have a lot of the information loaded into memory to subsequent calls so multiple users would use up far less memory then the initial?

 

I would assume the latter is the case based on the fact that reusing zend_date doesn't incur a 3MB hit every time. But without being admin of my server and hvaing tons of folks to test at once, its hard to tell.