commit 535e3f808f6b99a321fe914af393cc2d154580b1
Author: Damien Tournoud <damien@commerceguys.com>
Date:   Wed Dec 7 16:27:44 2011 +0100

    Issue #1363826: workaround deadlock issues when saving orders concurrently.

diff --git a/modules/order/commerce_order.install b/modules/order/commerce_order.install
index 71b89a2..5e5a6e2 100644
--- a/modules/order/commerce_order.install
+++ b/modules/order/commerce_order.install
@@ -19,13 +19,13 @@ function commerce_order_schema() {
         'description' => 'The order number displayed to the customer.',
         'type' => 'varchar',
         'length' => 255,
-        'not null' => TRUE,
+        'not null' => FALSE,
       ),
       'revision_id' => array(
         'description' => 'The current {commerce_order_revision}.revision_id version identifier.',
         'type' => 'int',
         'unsigned' => TRUE,
-        'not null' => TRUE,
+        'not null' => FALSE,
         'default' => 0,
       ),
       'type' => array(
@@ -112,7 +112,7 @@ function commerce_order_schema() {
         'description' => 'The order number displayed to the customer for this revision.',
         'type' => 'varchar',
         'length' => 255,
-        'not null' => TRUE,
+        'not null' => FALSE,
       ),
       'revision_id' => array(
         'description' => 'The primary identifier for this revision.',
diff --git a/modules/order/includes/commerce_order.controller.inc b/modules/order/includes/commerce_order.controller.inc
index d1cec78..a4cd94b 100644
--- a/modules/order/includes/commerce_order.controller.inc
+++ b/modules/order/includes/commerce_order.controller.inc
@@ -22,9 +22,9 @@ class CommerceOrderEntityController extends DrupalCommerceEntityController {
    */
   public function create(array $values = array()) {
     $values += array(
-      'order_id' => '',
-      'order_number' => '',
-      'revision_id' => '',
+      'order_id' => NULL,
+      'order_number' => NULL,
+      'revision_id' => NULL,
       'uid' => '',
       'mail' => ( !empty($values['uid']) && ($account = user_load($values['uid'])) ) ? $account->mail : '',
       'data' => array(),
@@ -119,6 +119,19 @@ class CommerceOrderEntityController extends DrupalCommerceEntityController {
     // Call the default attachLoad() method. This will add fields and call
     // hook_commerce_order_load().
     parent::attachLoad($queried_orders, $revision_id);
+
+    // Pre-load all the line items of the orders in one go.
+    $line_item_ids = array();
+    foreach ($queried_orders as $order_id => $order) {
+      foreach ($order->commerce_line_items as $langcode => $items) {
+        foreach ($items as $delta => $item) {
+          $line_item_ids[$item['line_item_id']] = TRUE;
+        }
+      }
+    }
+    if ($line_item_ids) {
+      entity_load('commerce_line_item', array_keys($line_item_ids));
+    }
   }
 
 }