Use persistent database connection by default.

mongodb-7.x-1.0-rc2-persist.patch

diff --git a/mongodb.module b/mongodb.module
index c5e4afa..35b4527 100644
--- a/mongodb.module
+++ b/mongodb.module
@@ -31,6 +31,9 @@ function mongodb($alias = 'default') {
   $db = $connection['db'];
   if (!isset($mongo_objects[$host][$db])) {
     try {
+      $options = variable_get('mongodb_options', array()) + array(
+        'persist' => '1', // Use persistent connection by default.
+      );
       $mongo = new Mongo($host, $options);
       $mongo_objects[$host][$db] = $mongo->selectDB($db);
       $mongo_objects[$host][$db]->connection = $mongo;