php memory de-allocation

[rsatd]

So after doing a spot of googling, I haven't found a good answer for this.

Got a script that runs daily on a client that operates on 500 records at a time. It fetches them and stores them in an object. What's the sensible way of clearing this object? What it does is this:

$obj = fetch500
while(more_records) {
   $obj = fetch500
   doStuff
}

Which is fine since the obj gets overwritten inside the while loop, but after the loop finishes, I want to clear the memory of this object. Should I use unset or set the object to NULL? Or something else that I am not aware of?

Yes I can increase memory limits... but I would prefer not to have a massive memory intensive script running daily xD.

 

[topbanana]

You should probably let the garbage collector clean up the memory for you.

If you must, you can call gc_collect_cycles

 

[GravyMonster]

Unless your server is an Amstrad CPC 464, 500 records is nothing at all. The inbuilt garbage collector would be more than capable of handling that.

 

[rsatd]

Oh yeah its not that much but it is for the environment in question. And I would rather improve the script rather then blindly increase memory limits. Those records generate a 15-20mb object when loaded (there are other overheads as we have to do soap calls and such and such, but anyway that's not the issue here.

Was mostly asking for a sensible way to clear memory used by the variable (or mark it up for garbage collection) that is no longer needed while staying in the same function scope.

 

[Dj_Jestar]

use unset if you are worried about it.

 

[visibleman]

From my understanding (could be wrong) - UNSET just removes the variable/object from the current scope and won't necessarily free up the variable/objects allocated memory (not until garbage collection, which i believe runs during idle cycles); whereas setting a variable/object to NULL clears the data, inturn freeing up allocated memory, but at cost of cpu cycles.

Edit - quick Google - http://stackoverflow.com/questions/584960/whats-better-at-freeing-memory-with-php-unset-or-var-null

 

[Dj_Jestar]

Worried about micro-managing the memory? Stop using PHP.

This is a complete non-issue. Unset your variables/references if you care to, and the garbage collector will do the rest. Not to mention all resources are killed once the script completes anyway. I cannot emphasise enough just how little this actually matters.

 

[GravyMonster]

^ Bam. Completely agree.

 

[aln]

From my understanding (could be wrong) - UNSET just removes the variable/object from the current scope and won't necessarily free up the variable/objects allocated memory (not until garbage collection, which i believe runs during idle cycles); whereas setting a variable/object to NULL clears the data, inturn freeing up allocated memory, but at cost of cpu cycles.

Edit - quick Google - http://stackoverflow.com/questions/584960/whats-better-at-freeing-memory-with-php-unset-or-var-null

So you unset it then call gc_collect_cycles(), I would imagine?

I've never used, probably never will, it but it's there if you really need it.