diff --git a/src/wp-admin/includes/schema.php b/src/wp-admin/includes/schema.php
index 795e9a88f6..c548ba7c6f 100644
--- a/src/wp-admin/includes/schema.php
+++ b/src/wp-admin/includes/schema.php
@@ -101,7 +101,8 @@ CREATE TABLE $wpdb->comments (
   KEY comment_post_ID (comment_post_ID),
   KEY comment_approved_date_gmt (comment_approved,comment_date_gmt),
   KEY comment_date_gmt (comment_date_gmt),
-  KEY comment_parent (comment_parent)
+  KEY comment_parent (comment_parent),
+  KEY comment_author_email (comment_author_email(10))
 ) $charset_collate;
 CREATE TABLE $wpdb->links (
   link_id bigint(20) unsigned NOT NULL auto_increment,
diff --git a/src/wp-includes/version.php b/src/wp-includes/version.php
index 455c9d6db9..8e35d7815b 100644
--- a/src/wp-includes/version.php
+++ b/src/wp-includes/version.php
@@ -11,7 +11,7 @@ $wp_version = '4.0-beta1-29138-src';
  *
  * @global int $wp_db_version
  */
-$wp_db_version = 27916;
+$wp_db_version = 29188;
 
 /**
  * Holds the TinyMCE version