Index: modules/node/node.module
===================================================================
--- modules/node/node.module	(revision 4057)
+++ modules/node/node.module	(working copy)
@@ -2043,6 +2043,7 @@
  */
 function node_access($op, $node, $account = NULL) {
   global $user;
+  static $rights = array();
 
   if (!$node || !in_array($op, array('view', 'update', 'delete', 'create'), TRUE)) {
     // If there was no node to check against, or the $op was not one of the
@@ -2057,6 +2058,11 @@
   if (empty($account)) {
     $account = $user;
   }
+
+  // Return cached value if it exists.
+  if (isset($node->nid) && isset($rights[$account->uid][$node->nid][$op])) {
+    return $rights[$account->uid][$node->nid][$op];
+  }
   // If the node is in a restricted format, disallow editing.
   if ($op == 'update' && !filter_access($node->format)) {
     return FALSE;
@@ -2078,6 +2084,9 @@
   }
   $access = module_invoke($module, 'access', $op, $node, $account);
   if (!is_null($access)) {
+    if (isset($node->nid)) {
+      $rights[$account->uid][$node->nid][$op] = $result;
+    }
     return $access;
   }
 
@@ -2098,6 +2107,7 @@
 
     $sql = "SELECT 1 FROM {node_access} WHERE (nid = 0 OR nid = %d) $grants_sql AND grant_$op >= 1";
     $result = db_query_range($sql, $node->nid, 0, 1);
+    $rights[$account->uid][$node->nid][$op] = (bool) $result;
     return (bool) db_result($result);
   }