Commit 3c8f1540 authored by webchick's avatar webchick

#414218 by cha0s: Document hook_update_N()'s ability to use batch API.

parent a88a999c
......@@ -1576,18 +1576,55 @@ function hook_install() {
* the same directory as mymodule.module. Drupal core's updates are implemented
* using the system module as a name and stored in database/updates.inc.
*
* If your update task is potentially time-consuming, you'll need to implement a
* multipass update to avoid PHP timeouts. Multipass updates use the $sandbox
* parameter provided by the batch API (normally, $context['sandbox']) to store
* information between successive calls, and the $ret['#finished'] return value
* to provide feedback regarding completion level.
*
* See the batch operations page for more information on how to use the batch API:
* @link http://drupal.org/node/146843 http://drupal.org/node/146843 @endlink
*
* @return An array with the results of the calls to update_sql(). An upate
* function can force the current and all later updates for this
* module to abort by returning a $ret array with an element like:
* $ret['#abort'] = array('success' => FALSE, 'query' => 'What went wrong');
* The schema version will not be updated in this case, and all the
* aborted updates will continue to appear on update.php as updates that
* have not yet been run.
* have not yet been run. Multipass update functions will also want to pass
* back the $ret['#finished'] variable to inform the batch API of progress.
*/
function hook_update_N() {
function hook_update_N(&$sandbox = NULL) {
// For most updates, the following is sufficient.
$ret = array();
db_add_field($ret, 'mytable1', 'newcol', array('type' => 'int', 'not null' => TRUE));
return $ret;
// However, for more complex operations that may take a long time,
// you may hook into Batch API as in the following example.
$ret = array();
// Update 3 users at a time to have an exclamation point after their names.
// (They're really happy that we can do batch API in this hook!)
if (!isset($sandbox['progress'])) {
$sandbox['progress'] = 0;
$sandbox['current_uid'] = 0;
// We'll -1 to disregard the uid 0...
$sandbox['max'] = db_query('SELECT COUNT(DISTINCT uid) FROM {users}')->fetchField() - 1;
}
$users = db_query_range("SELECT uid, name FROM {users} WHERE uid > %d ORDER BY uid ASC", $sandbox['current_uid'], 0, 3);
foreach ($users as $user) {
$user->name .= '!';
$ret[] = update_sql("UPDATE {users} SET name = '$user->name' WHERE uid = $user->uid");
$sandbox['progress']++;
$sandbox['current_uid'] = $user->uid;
}
$ret['#finished'] = empty($sandbox['max']) ? 1 : ($sandbox['progress'] / $sandbox['max']);
return $ret;
}
/**
......
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