Memory leak with $view->pre_execute() & $view->attach_displays()

Output:

$view->pre_execute() skipped, $view->execute() skipped; no memory leak
Before: 27525120
After: 27525120
Diff: 0


$view->pre_execute() ran, $view->execute() skipped; memory leak
Before: 27525120
After: 42205184
Diff: 14 mb


$view->pre_execute() skipped, $view->execute() ran; big memory leak
Before: 42205184
After: 85983232
Diff: 41.75 mb


$view->pre_execute() ran, $view->execute() ran; huge memory leak
Before: 85983232
After: 146800640
Diff: 58 mb

test code below

ini_set('memory_limit','512M');

// Prime views code (static caches)
test_view(TRUE, TRUE);


echo '$view->pre_execute() skipped, $view->execute() skipped; no memory leak<br>';
test_run(FALSE, FALSE);
echo '<br><br>';

echo '$view->pre_execute() ran, $view->execute() skipped; memory leak<br>';
test_run(TRUE, FALSE);
echo '<br><br>';

echo '$view->pre_execute() skipped, $view->execute() ran; big memory leak<br>';
test_run(FALSE, TRUE);
echo '<br><br>';

echo '$view->pre_execute() ran, $view->execute() ran; huge memory leak<br>';
test_run(TRUE, TRUE);
echo '<br><br>';


function test_run($pre_execute, $execute) {
  $before = memory_get_usage(TRUE);
  echo 'Before: ' . $before . '<br>';
  for ($i=0; $i<500; $i++) {
    test_view($pre_execute, $execute);
  }
  $after = memory_get_usage(TRUE);
  echo 'After: ' . $after . '<br>';
  $diff = test_convert($after - $before);
  echo 'Diff: ' . $diff . '<br>';
  unset($before);
  unset($after);
  unset($diff);
}

function test_view($pre_execute, $execute) {
  $view = views_get_view('frontpage', TRUE);
  $view->set_display('page');
  if ($pre_execute) {
    $view->pre_execute();
  }
  if ($execute) {
    $view->execute();
  }
  count($view->result);
  $view->destroy();
  unset($view);
  unset($pre_execute);
  unset($execute);
}

// php.net/memory-get-usage#96280
function test_convert($size) {
  $unit=array('b','kb','mb','gb','tb','pb');
  return @round($size/pow(1024,($i=floor(log($size,1024)))),2).' '.$unit[$i];
}

This solves one of the issues; going to dig into execute() next

  /**
   * Unset references so that a $view object may be properly garbage
   * collected.
   */
  function destroy() {
...
    unset($this->old_view);
...

$this->display_handler;

Has recursion in it, so my guess is it doesn't get destroyed correctly

Patch below fixes pre_execute(); still no solution to execute() leaking.

$view->pre_execute() skipped, $view->execute() skipped; no memory leak
Before: 23855104
After: 23855104
Diff: 0


$view->pre_execute() ran, $view->execute() skipped; memory leak
Before: 23855104
After: 23855104
Diff: 0


$view->pre_execute() skipped, $view->execute() ran; big memory leak
Before: 23855104
After: 67108864
Diff: 41.25 mb


$view->pre_execute() ran, $view->execute() ran; huge memory leak
Before: 67108864
After: 110624768
Diff: 41.5 mb

Screen shot showing the before and after on one of our servers. This patch helps a lot; but it could use more help.

Calling this instead of destroy()

function test_view_destroy(&$var) {
  if (is_array($var)) {
    foreach ($var as $key => $value) {
      if (is_array($value) || is_object($value)) {
        test_view_destroy($var[$key]);
      }
      unset($var[$key]);
    }
  }
  if (is_object($var)) {
    if (method_exists($var, 'destroy')) {
      echo get_class($var) . '<br>';
      $var->destroy();
    }
    foreach ($var as $key => $value) {
      if (is_array($value) || is_object($value)) {
        test_view_destroy($var->{$key});
      }
      unset($var->{$key});
    }
  }
  else {
    unset($var);
  }
}

These are the objects with a destroy method

view
views_plugin_display_default
views_plugin_display_page
views_handler_sort
views_handler_sort_date
views_handler_filter_boolean_operator
views_handler_filter_boolean_operator
views_plugin_display_feed
views_plugin_display_page
views_handler_sort
views_handler_sort_date
views_handler_filter_boolean_operator
views_handler_filter_boolean_operator
views_plugin_style_default
views_plugin_row_node_view

I've commented out views destroy() will try the rest and go from there.

Alt with a limit of 1000 in depth and it still doesn't clear out the memory; in fact I see no change in comparison.

  //$view->destroy();
  test_view_destroy($view);

function test_view_destroy(&$var, $level=0) {
  $level++;
  if ($level > 1000) {
    unset($var);
    return;
  }

  if (is_array($var)) {
    foreach ($var as $key => $value) {
      if (is_array($value) || is_object($value)) {
        test_view_destroy($var[$key], $level);
      }
      unset($var[$key]);
    }
  }
  if (is_object($var)) {
//     if (method_exists($var, 'destroy')) {
//       echo get_class($var) . '<br>';
//       $var->destroy();
//     }
    foreach ($var as $key => $value) {
      if (is_array($value) || is_object($value)) {
        test_view_destroy($var->{$key}, $level);
      }
      unset($var->{$key});
    }
  }
  else {
    unset($var);
  }
}

all objects inside the view

view
stdClass
views_display
views_plugin_display_default
views_plugin_display_page
views_plugin_display_feed
views_query
views_handler_sort
views_handler_sort_date

Thanks for the pointers :) Attach_displays leaks; Here is the line in question

        $this->display[$id]->handler->attach_to($this->current_display);

http://drupalcode.org/viewvc/drupal/contributions/modules/views/includes...

pinpointed it further; its in class views_plugin_display_feed; attach_to method.

    if ($plugin) {
      $clone = $this->view->clone_view();
      $clone->set_display($this->display->id);
      $clone->build_title();
      $plugin->attach_to($display_id, $this->get_path(), $clone->get_title());
    }

http://drupalcode.org/viewvc/drupal/contributions/modules/views/plugins/...

Fixes memory leak!
This patch should get some testing before getting committed. Views still works from my point of view with the patch applied.