Question

Do I need to worry about memory leaks with PHP? In particular, I have the following code that is being called from a browser. When the call finishes, is everything cleaned up properly, or, do I need to clear the memory created by the first array that was created?

class SomeClass
{
  var $someArray = array();

  function someMethod()
  {
     $this->someArray[1] = "Some Value 1";
     $this->someArray[2] = "Some Value 2";
     $this->someArray[3] = "Some Value 3";
     $this->someArray = array();
     $this->someArray[1] = "Some other Value";
     $this->someArray[2] = "Some other Value";
     $this->someArray[3] = "Some other Value";
  }
}

someMethod();

Thanks,
Scott

Answer 1

Do I need to worry about memory leaks with PHP?

It’s possible to have a cyclic reference in PHP where the refcount of the zval never drops to 0. This will cause a memory leak (GC won’t clean up objects that have a reference to them). This has been fixed in >= PHP 5.3.

In particular, I have the following code that is being called from a browser. When the call finishes, is everything cleaned up properly, or, do I need to clear the memory created by the first array that was created?

PHP scripts have a request lifecycle (run application, return response, close application), so it shouldn’t be a worry. All memory used by your application should be marked as free’d when your application finishes, ready to be overwritten on the next request.