> -----Original Message-----
> From: Nathan Nobbe [mailto:quickshif...@gmail.com]
> Sent: 16 June 2011 17:51

> Here's what's going on, I instantiate a model object for the product
> table
> from my application
> $newRecord = new Product();
> at this point memory usage goes up noticeably.  I don't really care
> though
> because I figure I can delete it, but look at this madness I have
> going
> (which *fails* to free up the memory)
> $newRecord->clearRelated();
> $newRecord->free();
> unset($newRecord);
> gc_collect_cycles();
> after all of this memory consumption is still dramatically higher
> than prior
> to the first call creating the object above.  This I've verified
> through
> memory_get_usage().
> here's the output from the memory_get_usage() calls
> int(166461440) // before new Product()
> int(169345024) // directly after new Product()
> int(169345024) // after madness trying to free memory used by new
> Product()

I know nothing about Doctrine, but after all the unrelated
discussion and your renewed plea for someone to address the issue,
I decided to write conduct some simple tests.

So I wrote a very simple class that basically just hogs some memory
when instantiated, and tried some simple instantiations and

At each stage, I measured current and peak memory usage, and the
results were:

    Usage = 262,144
    Peak  = 262,144

  After single instantiation ($a = new Hog();)
    Usage = 3,932,160
    Peak  = 3,932,160

  After resetting that to NULL ($a = NULL;)
    Usage = 524,288
    Peak  = 3,932,160

  After second single instantiation ($b = new Hog();)
    Usage = 3,932,160
    Peak  = 3,932,160

  After instantiating 3 more
    Usage = 15,728,640
    Peak  = 15,728,640

  After resetting all those to NULL
    Usage = 1,310,720
    Peak  = 15,728,640

  After 4 instantiations again
    Usage = 15,728,640
    Peak  = 15,728,640

This seems to be pretty much what I (and you!) would expect,
indicating that the memory used by objects can be recovered by PHP
when the object is released. This being the case, I would suggest
that something in your script is not freeing things up the way it
should, the prime candidate being the clearRelated() method. Either
that, or you have circular references that the gc_collect_cycles()
function is unable to recover. But, bottom line, I'd say you're
right that it's probably a Doctrine-related issue as the underlying
PHP functionality seems to work reasonably well.



Mike Ford,
Electronic Information Developer, Libraries and Learning Innovation,  
Leeds Metropolitan University, 507 Portland Building, City Campus, 
Portland Way, LEEDS,  LS1 3HE,  United Kingdom 
E: m.f...@leedsmet.ac.uk     T: +44 113 812 4730

To view the terms under which this email is distributed, please go to 

Reply via email to