diff --git a/modules/comment/comment.schema b/modules/comment/comment.schema
index acbbbfd6dd6512fc96b5acfad05a5be4bee82a75..057e55d96ec1a2c7b2b9cb23f8204c6fa9bf32df 100644
--- a/modules/comment/comment.schema
+++ b/modules/comment/comment.schema
@@ -28,7 +28,7 @@ function comment_schema() {
 
   $schema['node_comment_statistics'] = array(
     'fields' => array(
-      'nid'                    => array('type' => 'serial', 'unsigned' => TRUE, 'not null' => TRUE),
+      'nid'                    => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
       'last_comment_timestamp' => array('type' => 'int', 'not null' => TRUE, 'default' => 0),
       'last_comment_name'      => array('type' => 'varchar', 'length' => 60, 'not null' => FALSE),
       'last_comment_uid'       => array('type' => 'int', 'not null' => TRUE, 'default' => 0),
diff --git a/modules/system/system.install b/modules/system/system.install
index fe70b3581ef6a7e999941d28e6869cb50cfbbabd..d0f42be238c515189f0e1211d20f4d6b937ab66c 100644
--- a/modules/system/system.install
+++ b/modules/system/system.install
@@ -3194,7 +3194,7 @@ function system_update_6019() {
         db_drop_primary_key($ret, 'term_node');
         db_add_primary_key($ret, 'term_node', array('vid', 'tid', 'nid'));
       }
-      
+
       // Make boxes.bid unsigned.
       db_drop_primary_key($ret, 'boxes');
       db_change_field($ret, 'boxes', 'bid', 'bid', array('type' => 'serial', 'unsigned' => TRUE, 'not null' => TRUE), array('primary key' => array('bid')));
@@ -3765,6 +3765,18 @@ function system_update_6032() {
   return $ret;
 }
 
+/**
+ * Change node_comment_statistics to be not autoincrement.
+ */
+function system_update_6033() {
+  $ret = array();
+  if (db_table_exists('node_comment_statistics')) {
+    db_change_field($ret, 'node_comment_statistics', 'nid', 'nid', array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0)
+  }
+  return $ret;
+}
+
+
 /**
  * @} End of "defgroup updates-5.x-to-6.x"
  * The next series of updates should start at 7000.