- Patch #324313 by catch et al: load multiple nodes and terms at once.

CHANGELOG.txt

@@ -32,6 +32,9 @@ Drupal 7.0, xxxx-xx-xx (development version)
     * Redesigned password strength validator.
     * Redesigned the add content type screen.
     * Highlight duplicate URL aliases.
+- Performance:
+    * Improved performance on uncached page views by loading multiple core
+      objects in a single database query.
 - Documentation:
     * Hook API documentation now included in Drupal core.
 - News aggregator:

modules/book/book.module

@@ -705,18 +705,13 @@ function book_build_active_trail($book_link) {
 /**
  * Implementation of hook_nodeapi_load().
  */
-function book_nodeapi_load(&$node, $teaser, $page) {
-  // Note - we cannot use book_link_load() because it will call node_load().
-  $info['book'] = db_query('SELECT * FROM {book} b INNER JOIN {menu_links} ml ON b.mlid = ml.mlid WHERE b.nid = :nid', array(
-    ':nid' => $node->nid
-  ))->fetchAssoc();
-
-  if ($info['book']) {
-    $info['book']['href'] = $info['book']['link_path'];
-    $info['book']['title'] = $info['book']['link_title'];
-    $info['book']['options'] = unserialize($info['book']['options']);
-
-    return $info;
+function book_nodeapi_load($nodes, $types) {
+  $result = db_query("SELECT * FROM {book} b INNER JOIN {menu_links} ml ON b.mlid = ml.mlid WHERE b.nid IN (" . db_placeholders(array_keys($nodes)) . ")",  array_keys($nodes), array('fetch' => PDO::FETCH_ASSOC));
+  foreach ($result as $record) {
+    $nodes[$record['nid']]->book = $record;
+    $nodes[$record['nid']]->book['href'] = $record['link_path'];
+    $nodes[$record['nid']]->book['title'] = $record['link_title'];
+    $nodes[$record['nid']]->book['options'] = unserialize($record['options']);
   }
 }
 

modules/book/book.test

@@ -146,7 +146,7 @@ class BookTestCase extends DrupalWebTestCase {
     }
 
     // Check to make sure the book node was created.
-    $node = node_load(array('title' => $edit['title']));
+    $node = $this->drupalGetNodeByTitle($edit['title']);
     $this->assertNotNull(($node === FALSE ? NULL : $node), t('Book node found in database.'));
     $number++;
 

modules/comment/comment.module

@@ -579,11 +579,32 @@ function comment_form_alter(&$form, $form_state, $form_id) {
 /**
  * Implementation of hook_nodeapi_load().
  */
-function comment_nodeapi_load(&$node, $arg = 0) {
-  if ($node->comment != COMMENT_NODE_DISABLED) {
-    return db_query('SELECT last_comment_timestamp, last_comment_name, comment_count FROM {node_comment_statistics} WHERE nid = :nid', array(':nid' => $node->nid))->fetchAssoc();
+function comment_nodeapi_load($nodes, $types) {
+  $comments_enabled = array();
+
+  // Check if comments are enabled for each node. If comments are disabled,
+  // assign values without hitting the database.
+  foreach ($nodes as $node) {
+    // Store whether comments are enabled for this node.
+    if ($node->comment != COMMENT_NODE_DISABLED) {
+      $comments_enabled[] = $node->nid;
+    }
+    else {
+      $node->last_comment_timestamp = $node->created;
+      $node->last_comment_name = '';
+      $node->comment_count = 0;
+    }
+  }
+
+  // For nodes with comments enabled, fetch information from the database.
+  if (!empty($comments_enabled)) {
+    $result = db_query('SELECT nid, last_comment_timestamp, last_comment_name, comment_count FROM {node_comment_statistics} WHERE nid IN(' . db_placeholders($comments_enabled) . ')', $comments_enabled);
+    foreach ($result as $record) {
+      $nodes[$record->nid]->last_comment_timestamp = $record->last_comment_timestamp;
+      $nodes[$record->nid]->last_comment_name = $record->last_comment_name;
+      $nodes[$record->nid]->comment_count = $record->comment_count;
+    }
   }
-  return array('last_comment_timestamp' => $node->created, 'last_comment_name' => '', 'comment_count' => 0);
 }
 
 /**

modules/dblog/dblog.test

@@ -262,7 +262,7 @@ class DBLogTestCase extends DrupalWebTestCase {
     $this->drupalPost('node/add/' . $type, $edit, t('Save'));
     $this->assertResponse(200);
     // Retrieve node object.
-    $node = node_load(array('title' => $title));
+    $node = $this->drupalGetNodeByTitle($title);
     $this->assertTrue($node != null, t('Node @title was loaded', array('@title' => $title)));
     // Edit node.
     $edit = $this->getContentUpdate($type);

modules/filter/filter.test

@@ -114,7 +114,7 @@ class FilterAdminTestCase extends DrupalWebTestCase {
     $this->drupalPost('node/add/page', $edit, t('Save'));
     $this->assertRaw(t('Page %title has been created.', array('%title' => $edit['title'])), t('Filtered node created.'));
 
-    $node = node_load(array('title' => $edit['title']));
+    $node = $this->drupalGetNodeByTitle($edit['title']);
     $this->assertTrue($node, t('Node found in database.'));
 
     $this->drupalGet('node/' . $node->nid);

modules/forum/forum.module

@@ -341,11 +341,25 @@ function forum_nodeapi_delete(&$node, $teaser, $page) {
 /**
  * Implementation of hook_nodeapi_load().
  */
-function forum_nodeapi_load(&$node, $teaser, $page) {
+function forum_nodeapi_load($nodes, $types) {
   $vid = variable_get('forum_nav_vocabulary', '');
+  // If no forum vocabulary is set up, return.
+  if ($vid == '') {
+    return;
+  }
   $vocabulary = taxonomy_vocabulary_load($vid);
-  if (_forum_nodeapi_check_node_type($node, $vocabulary)) {
-    return db_fetch_array(db_query('SELECT tid AS forum_tid FROM {forum} WHERE vid = %d', $node->vid));
+
+  $node_vids = array();
+  foreach ($nodes as $node) {
+    if (isset($vocabulary->nodes[$node->type])) {
+      $node_vids[] = $node->vid;
+    }
+  }
+  if (!empty($node_vids)) {
+    $result = db_query('SELECT nid, tid FROM {forum} WHERE vid IN(' . db_placeholders($node_vids) . ')', $node_vids);
+    foreach ($result as $record) {
+      $nodes[$record->nid]->forum_tid = $record->tid;
+    }
   }
 }
 
@@ -451,15 +465,6 @@ function forum_form_alter(&$form, $form_state, $form_id) {
   }
 }
 
-/**
- * Implementation of hook_load().
- */
-function forum_load($node) {
-  $forum = db_fetch_object(db_query('SELECT * FROM {term_node} WHERE vid = %d', $node->vid));
-
-  return $forum;
-}
-
 /**
  * Implementation of hook_block().
  *

modules/forum/forum.test

@@ -236,7 +236,7 @@ class ForumTestCase extends DrupalWebTestCase {
     }
 
     // Retrieve node object.
-    $node = node_load(array('title' => $title), null, true); // Are these last two parameters necessary?
+    $node = $this->drupalGetNodeByTitle($title);
     $this->assertTrue($node != null, t('Node @title was loaded', array('@title' => $title)));
 
     // View forum topic.

modules/node/node.api.php

@@ -154,6 +154,39 @@ function hook_node_operations() {
   return $operations;
 }
 
+/**
+ * Act on node objects when loaded.
+ *
+ * This hook allows you to add information to node objects when loaded from
+ * the database. It takes an array of nodes indexed by nid as its first
+ * parameter. For performance reasons, information for all available nodes
+ * should be loaded in a single query where possible.
+ *
+ * The types of all nodes being passed in are also available in the $types
+ * parameter. If your module keeps track of the node types it supports, this
+ * allows for an early return if nothing needs to be done.
+ *
+ * Due to the internal cache in node_load_multiple(), you should not use this
+ * hook to modify information returned from the {node} table itself, since
+ * this may affect the way nodes are returned from the cache in subsequent
+ * calls to the function.
+ *
+ * @see comment_nodeapi_load()
+ * @see taxonomy_nodeapi_load()
+ * @see forum_nodeapi_load()
+ *
+ * @param $nodes
+ *   An array of node objects indexed by nid.
+ * @param $types
+ *   An array containing the types of the nodes.
+ */
+function hook_nodeapi_load($nodes, $types) {
+  $result = db_query('SELECT nid, foo FROM {mytable} WHERE nid IN(' . db_placeholders(array_keys($nodes)) . ')', array_keys($nodes));
+  foreach ($result as $record) {
+    $nodes[$record->nid]->foo = $record->foo;
+  }
+}
+
 /**
  * Act on nodes defined by other modules.
  *
@@ -521,25 +554,22 @@ function hook_insert($node) {
  * Load node-type-specific information.
  *
  * This is a hook used by node modules. It is called to allow the module
- * a chance to load extra information that it stores about a node, or
- * possibly replace already loaded information - which can be dangerous.
+ * a chance to load extra information that it stores about a node. The hook
+ * should not be used to replace information from the core {node} table since
+ * this may interfere with the way nodes are fetched from cache.
  *
- * @param $node
- *   The node being loaded. At call time, node.module has already loaded
- *   the basic information about the node, such as its node ID (nid),
- *   title, and body.
- * @return
- *   An object containing properties of the node being loaded. This will
- *   be merged with the passed-in $node to result in an object containing
- *   a set of properties resulting from adding the extra properties to
- *   the passed-in ones, and overwriting the passed-in ones with the
- *   extra properties if they have the same name as passed-in properties.
+ * @param $nodes
+ *   An array of the nodes being loaded, keyed by nid. At call time,
+ *   node.module has already loaded the basic information about the nodes, such
+ *   as node ID (nid), title, and body.
  *
  * For a detailed usage example, see node_example.module.
  */
-function hook_load($node) {
-  $additions = db_fetch_object(db_query('SELECT * FROM {mytable} WHERE vid = %d', $node->vid));
-  return $additions;
+function hook_load($nodes) {
+  $result = db_fetch_object(db_query('SELECT nid, foo FROM {mytable} WHERE nid IN (' . db_placeholders(array_keys($nodes)) . ')', array_keys($nodes)));
+  foreach ($result as $record) {
+    $nodes[$record->nid]->foo = $record->foo;
+  }
 }
 
 /**

modules/node/node.module

@@ -730,93 +730,177 @@ function node_invoke_nodeapi(&$node, $op, $a3 = NULL, $a4 = NULL) {
 }
 
 /**
- * Load a node object from the database.
+ * Load node objects from the database.
+ *
+ * This function should be used whenever you need to load more than one node
+ * from the database. Nodes are loaded into memory and will not require
+ * database access if loaded again during the same page request.
  *
- * @param $param
- *   Either the nid of the node or an array of conditions to match against in the database query
- * @param $revision
- *   Which numbered revision to load. Defaults to the current version.
+ * @param $nids
+ *   An array of node IDs.
+ * @param $conditions
+ *   An array of conditions on the {node} table in the form 'field' => $value.
  * @param $reset
  *   Whether to reset the internal node_load cache.
  *
  * @return
- *   A fully-populated node object.
+ *   An array of node objects indexed by nid.
  */
-function node_load($param = array(), $revision = NULL, $reset = NULL) {
-  static $nodes = array();
-
+function node_load_multiple($nids = array(), $conditions = array(), $reset = FALSE) {
+  static $node_cache = array();
   if ($reset) {
-    $nodes = array();
-  }
-
-  $cachable = ($revision == NULL);
-  $arguments = array();
-  if (is_numeric($param)) {
-    if ($cachable) {
-      // Is the node statically cached?
-      if (isset($nodes[$param])) {
-        return is_object($nodes[$param]) ? clone $nodes[$param] : $nodes[$param];
+    $node_cache = array();
+  }
+  $nodes = array();
+
+  // Create a new variable which is either a prepared version of the $nids
+  // array for later comparison with the node cache, or FALSE if no $nids were
+  // passed. The $nids array is reduced as items are loaded from cache, and we
+  // need to know if it's empty for this reason to avoid querying the database
+  // when all requested nodes are loaded from cache.
+  $passed_nids = !empty($nids) ? array_flip($nids) : FALSE;
+
+  // Revisions are not statically cached, and require a different query to
+  // other conditions, so separate vid into its own variable.
+  $vid = isset($conditions['vid']) ? $conditions['vid'] : FALSE;
+  unset($conditions['vid']);
+
+  // Load any available nodes from the internal cache.
+  if ($node_cache && !$vid) {
+    if ($nids) {
+      $nodes += array_intersect_key($node_cache, $passed_nids);
+      // If any nodes were loaded, remove them from the $nids still to load.
+      $nids = array_keys(array_diff_key($passed_nids, $nodes));
+    }
+    // If loading nodes only by conditions, fetch all available nodes from
+    // the cache. Nodes which don't match are removed later.
+    elseif ($conditions) {
+      $nodes = $node_cache;
+    }
+  }
+
+  // Exclude any nodes loaded from cache if they don't match $conditions.
+  // This ensures the same behaviour whether loading from memory or database.
+  if ($conditions) {
+    foreach ($nodes as $node) {
+      $node_values = (array) $node;
+      if (array_diff_assoc($conditions, $node_values)) {
+        unset($nodes[$node->nid]);
       }
     }
-    $cond = 'n.nid = %d';
-    $arguments[] = $param;
   }
-  elseif (is_array($param)) {
-    // Turn the conditions into a query.
-    foreach ($param as $key => $value) {
-      $cond[] = 'n.' . db_escape_table($key) . " = '%s'";
-      $arguments[] = $value;
+
+  // Load any remaining nodes from the database. This is the case if there are
+  // any $nids left to load, if loading a revision, or if $conditions was
+  // passed without $nids.
+  if ($nids || $vid || ($conditions && !$passed_nids)) {
+    $query = db_select('node', 'n');
+
+    if ($vid) {
+      $query->join('node_revision', 'r', 'r.nid = n.nid AND r.vid = :vid', array(':vid' => $vid));
     }
-    $cond = implode(' AND ', $cond);
-  }
-  else {
-    return FALSE;
-  }
+    else {
+      $query->join('node_revision', 'r', 'r.vid = n.vid');
+    }
+    $query->join('users', 'u', 'u.uid = n.uid');
 
-  // Retrieve a field list based on the site's schema.
-  $fields = drupal_schema_fields_sql('node', 'n');
-  $fields = array_merge($fields, drupal_schema_fields_sql('node_revision', 'r'));
-  $fields = array_merge($fields, array('u.name', 'u.picture', 'u.data'));
-  // Remove fields not needed in the query: n.vid and r.nid are redundant,
-  // n.title is unnecessary because the node title comes from the
-  // node_revisions table.  We'll keep r.vid, r.title, and n.nid.
-  $fields = array_diff($fields, array('n.vid', 'n.title', 'r.nid'));
-  $fields = implode(', ', $fields);
-  // Rename timestamp field for clarity.
-  $fields = str_replace('r.timestamp', 'r.timestamp AS revision_timestamp', $fields);
-  // Change name of revision uid so it doesn't conflict with n.uid.
-  $fields = str_replace('r.uid', 'r.uid AS revision_uid', $fields);
-
-  // Retrieve the node.
-  // No db_rewrite_sql is applied so as to get complete indexing for search.
-  if ($revision) {
-    array_unshift($arguments, $revision);
-    $node = db_fetch_object(db_query('SELECT ' . $fields . ' FROM {node} n INNER JOIN {users} u ON u.uid = n.uid INNER JOIN {node_revision} r ON r.nid = n.nid AND r.vid = %d WHERE ' . $cond, $arguments));
-  }
-  else {
-    $node = db_fetch_object(db_query('SELECT ' . $fields . ' FROM {node} n INNER JOIN {users} u ON u.uid = n.uid INNER JOIN {node_revision} r ON r.vid = n.vid WHERE ' . $cond, $arguments));
-  }
+    // Add fields from the {node} table.
+    $node_fields = drupal_schema_fields_sql('node');
+
+    // vid and title are provided by node_revision, so remove them.
+    unset($node_fields['vid']);
+    unset($node_fields['title']);
+    $query->fields('n', $node_fields);
+
+    // Add all fields from the {node_revision} table.
+    $node_revision_fields = drupal_schema_fields_sql('node_revision');
+
+    // nid is provided by node, so remove it.
+    unset($node_revision_fields['nid']);
 
-  if ($node && $node->nid) {
-    // Call the node specific callback (if any) and piggy-back the
-    // results to the node or overwrite some values.
-    if ($extra = node_invoke($node, 'load')) {
-      foreach ($extra as $key => $value) {
-        $node->$key = $value;
+    // Change timestamp to revision_timestamp before adding it to the query.
+    unset($node_revision_fields['timestamp']);
+    $query->addField('r', 'timestamp', 'revision_timestamp');
+    $query->fields('r', $node_revision_fields);
+
+    // Add fields from the {users} table.
+    $user_fields = array('name', 'picture', 'data');
+    $query->fields('u', $user_fields);
+
+    if ($nids) {
+      $query->condition('n.nid', $nids, 'IN');
+    }
+    if ($conditions) {
+      foreach ($conditions as $field => $value) {
+        $query->condition('n.' . $field, $value);
       }
     }
+    $queried_nodes = $query->execute()->fetchAllAssoc('nid');
+  }
+
+  // Pass all nodes loaded from the database through the node type specific
+  // callbacks and hook_nodeapi_load(), then add them to the internal cache.
+  if (!empty($queried_nodes)) {
+    // Create an array of nodes for each content type and pass this to the
+    // node type specific callback.
+    $typed_nodes = array();
+    foreach ($queried_nodes as $nid => $node) {
+      $typed_nodes[$node->type][$nid] = $node;
+    }
 
-    if ($extra = node_invoke_nodeapi($node, 'load')) {
-      foreach ($extra as $key => $value) {
-        $node->$key = $value;
+    // Call node type specific callbacks on each typed array of nodes.
+    foreach ($typed_nodes as $type => $nodes_of_type) {
+      if (node_hook($type, 'load')) {
+        $function = node_get_types('base', $type) . '_load';
+        $function($nodes_of_type);
       }
     }
-    if ($cachable) {
-      $nodes[$node->nid] = is_object($node) ? clone $node : $node;
+
+    // Call hook_nodeapi_load(), pass the node types so modules can return early
+    // if not acting on types in the array.
+    foreach (module_implements('nodeapi_load') as $module) {
+      $function = $module . '_nodeapi_load';
+      $function($queried_nodes, array_keys($typed_nodes));
+    }
+    $nodes += $queried_nodes;
+    // Add nodes to the cache if we're not loading a revision.
+    if (!$vid) {
+      $node_cache += $queried_nodes;
     }
   }
 
-  return $node;
+  // Ensure that the returned array is ordered the same as the original $nids
+  // array if this was passed in and remove any invalid nids.
+  if ($passed_nids) {
+    // Remove any invalid nids from the array.
+    $passed_nids = array_intersect_key($passed_nids, $nodes);
+    foreach ($nodes as $node) {
+      $passed_nids[$node->nid] = $node;
+    }
+    $nodes = $passed_nids;
+  }
+
+  return $nodes;
+}
+
+/**
+ * Load a node object from the database.
+ *
+ * @param $nid
+ *   The node ID.
+ * @param $vid
+ *   The revision ID.
+ * @param $reset
+ *   Whether to reset the internal node_load cache.
+ *
+ * @return
+ *   A fully-populated node object.
+ */
+function node_load($nid, $vid = array(), $reset = FALSE) {
+  $vid = isset($vid) ? array('vid' => $vid) : NULL;
+  $node = node_load_multiple(array($nid), $vid, $reset);
+
+  return $node ? $node[$nid] : FALSE;
 }
 
 /**
@@ -1740,22 +1824,18 @@ function node_feed($nids = FALSE, $channel = array()) {
   global $base_url, $language;
 
   if ($nids === FALSE) {
-    $nids = array();
-    $result = db_query_range(db_rewrite_sql('SELECT n.nid, n.created FROM {node} n WHERE n.promote = 1 AND n.status = 1 ORDER BY n.created DESC'), 0, variable_get('feed_default_items', 10));
-    while ($row = db_fetch_object($result)) {
-      $nids[] = $row->nid;
-    }
+    $nids = db_query_range(db_rewrite_sql('SELECT n.nid, n.created FROM {node} n WHERE n.promote = 1 AND n.status = 1 ORDER BY n.created DESC'), 0, variable_get('feed_default_items', 10))->fetchCol();
   }
 
   $item_length = variable_get('feed_item_length', 'teaser');
   $namespaces = array('xmlns:dc' => 'http://purl.org/dc/elements/1.1/');
 
+  // Load all nodes to be rendered.
+  $nodes = node_load_multiple($nids);
   $items = '';
-  foreach ($nids as $nid) {
-    // Load the specified node:
-    $item = node_load($nid);
+  foreach ($nodes as $item) {
     $item->build_mode = NODE_BUILD_RSS;
-    $item->link = url("node/$nid", array('absolute' => TRUE));
+    $item->link = url("node/$item->nid", array('absolute' => TRUE));
 
     if ($item_length != 'title') {
       $teaser = ($item_length == 'teaser');
@@ -1822,16 +1902,14 @@ function node_feed($nids = FALSE, $channel = array()) {
  * Menu callback; Generate a listing of promoted nodes.
  */
 function node_page_default() {
-  $result = pager_query(db_rewrite_sql('SELECT n.nid, n.sticky, n.created FROM {node} n WHERE n.promote = 1 AND n.status = 1 ORDER BY n.sticky DESC, n.created DESC'), variable_get('default_nodes_main', 10));
-
-  $output = '';
-  $num_rows = FALSE;
-  while ($node = db_fetch_object($result)) {
-    $output .= node_view(node_load($node->nid), 1);
-    $num_rows = TRUE;
-  }
+  $nids = pager_query(db_rewrite_sql('SELECT n.nid FROM {node} n WHERE n.promote = 1 AND n.status = 1 ORDER BY n.sticky DESC, n.created DESC'), variable_get('default_nodes_main', 10))->fetchCol();
+  if (!empty($nids)) {
+    $nodes = node_load_multiple($nids);
+    $output = '';
+    foreach ($nodes as $node) {
+      $output .= node_view($node, TRUE);
+    }
 
-  if ($num_rows) {
     $feed_url = url('rss.xml', array('absolute' => TRUE));
     drupal_add_feed($feed_url, variable_get('site_name', 'Drupal') . ' ' . t('RSS'));
     $output .= theme('pager', NULL, variable_get('default_nodes_main', 10));

modules/node/node.test

 <?php
 // $Id$
 
+/**
+ * Test the node_load_multiple() function.
+ */
+class NodeLoadMultipleUnitTest extends DrupalWebTestCase {
+
+  function getInfo() {
+    return array(
+      'name' => t('Load multiple nodes'),
+      'description' => t('Test the loading of multiple nodes.'),
+      'group' => t('Node'),
+    );
+  }
+
+  function setUp() {
+    parent::setUp();
+    $web_user = $this->drupalCreateUser(array('create article content', 'create page content'));
+    $this->drupalLogin($web_user);
+  }
+
+  /**
+   * Create four nodes and ensure they're loaded correctly.
+   */
+  function testNodeMultipleLoad() {
+    $node1 = $this->drupalCreateNode(array('type' => 'article', 'promote' => 1));
+    $node2 = $this->drupalCreateNode(array('type' => 'article', 'promote' => 1));
+    $node3 = $this->drupalCreateNode(array('type' => 'article', 'promote' => 0));
+    $node4 = $this->drupalCreateNode(array('type' => 'page', 'promote' => 0));
+
+    // Confirm that promoted nodes appear in the default node listing.
+    $this->drupalGet('node');
+    $this->assertText($node1->title, t('Node title appears on the default listing.'));
+    $this->assertText($node2->title, t('Node title appears on the default listing.'));
+    $this->assertNoText($node3->title, t('Node title does not appear in the default listing.'));
+    $this->assertNoText($node4->title, t('Node title does not appear in the default listing.'));
+
+    // Load nodes with only a condition. Nodes 3 and 4 will be loaded.
+    $nodes = node_load_multiple(NULL, array('promote' => 0));
+    $this->assertEqual($node3->title, $nodes[$node3->nid]->title, t('Node was loaded.'));
+    $this->assertEqual($node4->title, $nodes[$node4->nid]->title, t('Node was loaded.'));
+    $count = count($nodes);
+    $this->assertTrue($count == 2, t('@count nodes loaded.', array('@count' => $count)));
+
+    // Load nodes by nid. Nodes 1, 2 and 4 will be loaded.
+    $nodes = node_load_multiple(array(1, 2, 4));
+    $count = count($nodes);
+    $this->assertTrue(count($nodes) == 3, t('@count nodes loaded', array('@count' => $count)));
+    $this->assertTrue(isset($nodes[$node1->nid]), t('Node is correctly keyed in the array'));
+    $this->assertTrue(isset($nodes[$node2->nid]), t('Node is correctly keyed in the array'));
+    $this->assertTrue(isset($nodes[$node4->nid]), t('Node is correctly keyed in the array'));
+    foreach ($nodes as $node) {
+      $this->assertTrue(is_object($node), t('Node is an object'));
+    }
+
+    // Load nodes by nid, where type = article. Nodes 1, 2 and 3 will be loaded.
+    $nodes = node_load_multiple(array(1, 2, 3, 4), array('type' => 'article'));
+    $count = count($nodes);
+    $this->assertTrue($count == 3, t('@count nodes loaded', array('@count' => $count)));
+    $this->assertEqual($nodes[$node1->nid]->title, $node1->title, t('Node successfully loaded.'));
+    $this->assertEqual($nodes[$node2->nid]->title, $node2->title, t('Node successfully loaded.'));
+    $this->assertEqual($nodes[$node3->nid]->title, $node3->title, t('Node successfully loaded.'));
+    $this->assertFalse(isset($nodes[$node4->nid]));
+
+    // Now that all nodes have been loaded into the static cache, ensure that
+    // they are loaded correctly again when a condition is passed.
+    $nodes = node_load_multiple(array(1, 2, 3, 4), array('type' => 'article'));
+    $count = count($nodes);
+    $this->assertTrue($count == 3, t('@count nodes loaded.', array('@count' => $count)));