function variable_initialize in Drupal 7

Loads the persistent variable table.

The variable table is composed of values that have been saved in the table with variable_set() as well as those explicitly specified in the configuration file.

3 calls to variable_initialize()

DrupalWebTestCase::refreshVariables in modules/simpletest/drupal_web_test_case.php

Refresh the in-memory set of variables. Useful after a page request is made that changes a variable in a different thread.

_drupal_bootstrap_variables in includes/bootstrap.inc

Loads system variables and all enabled bootstrap modules.

_menu_check_rebuild in includes/menu.inc

Checks whether a menu_rebuild() is necessary.

File

includes/bootstrap.inc, line 1185

Functions that need to be loaded on every Drupal request.

Code

function variable_initialize($conf = array()) {

  // NOTE: caching the variables improves performance by 20% when serving
  // cached pages.
  if ($cached = cache_get('variables', 'cache_bootstrap')) {
    $variables = $cached->data;
  }
  else {

    // Cache miss. Avoid a stampede by acquiring a lock. If the lock fails to
    // acquire, optionally just continue with uncached processing.
    $name = 'variable_init';
    $lock_acquired = lock_acquire($name, 1);
    if (!$lock_acquired && variable_get('variable_initialize_wait_for_lock', FALSE)) {
      lock_wait($name);
      return variable_initialize($conf);
    }
    else {

      // Load the variables from the table.
      $variables = array_map('unserialize', db_query('SELECT name, value FROM {variable}')
        ->fetchAllKeyed());
      if ($lock_acquired) {
        cache_set('variables', $variables, 'cache_bootstrap');
        lock_release($name);
      }
    }
  }
  foreach ($conf as $name => $value) {
    $variables[$name] = $value;
  }
  return $variables;
}