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To: internals@lists.php.net
Date: Tue, 9 Aug 2005 17:07:17 +0200
Lines: 48
Subject: drastic memory consumption with a sequence of exceptions
From: r.korving@xit.nl ("Ron Korving")

I've noticed that in a script of mine, memory consumption can explode quite
drastically when Exceptions are thrown, opposed to very normal memory
consumption when exceptions are not thrown.

This is the idea:

<?
class Obj
{
  function process($i)
  {
    // do a lot of stuff, occupy a lot of memory within the scope of this
function
    throw new Exception("error");
  }
}

$obj = new Obj();
$errors = array();

for ($i=0; $i < 60; $i++)
{
  try
  {
    $obj->process();
  }
  catch (Exception $e)
  {
    $errors[] = $e->getMessage();
  }
}
?>

When exceptions are not thrown, memory consumption is normal. The method's
local vars are freed and not much more memory is used in the 50th pass
compared to the 1st. But when exceptions are thrown, memory consumption
increases quite a bit every pass. In the end (within the 60 passes of my
loop) over 8 MB's are used.

Of course, I can unset a lot of data before throwing exceptions to free up
memory and the problem will be solved. But it would be nicer if the cleanup
would happen as an exception is thrown.

Can this be considered a bug or is this behavior known and accepted?

Ron