diff --git a/core/modules/comment/comment.install b/core/modules/comment/comment.install
index c159049..d1a9395 100644
--- a/core/modules/comment/comment.install
+++ b/core/modules/comment/comment.install
@@ -206,8 +206,8 @@ function comment_schema() {
       'comment_status_pid' => array('pid', 'status'),
       'comment_num_new' => array(
         'entity_id',
-        'entity_type',
-        'field_name',
+        array('entity_type', 32),
+        array('field_name', 32),
         'status',
         'created',
         'cid',
@@ -216,8 +216,8 @@ function comment_schema() {
       'comment_uid' => array('uid'),
       'comment_entity_langcode' => array(
         'entity_id',
-        'entity_type',
-        'field_name',
+        array('entity_type', 32),
+        array('field_name', 32),
         'langcode',
       ),
       'comment_created' => array('created'),
@@ -291,7 +291,7 @@ function comment_schema() {
         'description' => 'The total number of comments on this entity.',
       ),
     ),
-    'primary key' => array('entity_id', 'entity_type', 'field_name'),
+    'primary key' => array('entity_id', array('entity_type', 32), array('field_name', 32)),
     'indexes' => array(
       'last_comment_timestamp' => array('last_comment_timestamp'),
       'comment_count' => array('comment_count'),
@@ -449,14 +449,14 @@ function comment_update_8004() {
  * Updates the comment_node_statistics and comment tables to new structure.
  */
 function comment_update_8005(&$sandbox) {
-  // Remove the comment_node foreign key.
+  // Drop the comment_node foreign key.
   if (db_index_exists('comment', 'comment_node')) {
     db_drop_index('comment', 'comment_node');
   }
-  // Remove the comment_nid_langcode index.
+  // Drop old indexes.
   db_drop_index('comment', 'comment_nid_langcode');
-  // Remove comment_num_new index to create new latter here.
   db_drop_index('comment', 'comment_num_new');
+
   // Add the entity_type and field_name columns to comment.
   db_add_field('comment', 'entity_type', array(
     'type' => 'varchar',
@@ -481,8 +481,8 @@ function comment_update_8005(&$sandbox) {
   ));
   db_add_index('comment', 'comment_num_new', array(
     'entity_id',
-    'entity_type',
-    'field_name',
+    array('entity_type', 32),
+    array('field_name', 32),
     'status',
     'created',
     'cid',
@@ -491,22 +491,22 @@ function comment_update_8005(&$sandbox) {
   // Add the comment_entity_langcode index.
   db_add_index('comment', 'comment_entity_langcode', array(
     'entity_id',
-    'entity_type',
-    'field_name',
+    array('entity_type', 32),
+    array('field_name', 32),
     'langcode',
   ));
 
-  // Rename node_comment_statistics to comment_entity_statistics.
-  // Remove the statistics_node foreign key.
+  // We need to drop all indexes to make sure their constrains named properly.
   if (db_index_exists('node_comment_statistics', 'statistics_node')) {
+    // Remove the statistics_node foreign key.
     db_drop_index('node_comment_statistics', 'statistics_node');
   }
-  // We need to drop all indexes to make sure their constrains named properly.
   db_drop_primary_key('node_comment_statistics');
   db_drop_index('node_comment_statistics', 'node_comment_timestamp');
 
+  // Rename {node_comment_statistics} to {comment_entity_statistics}.
   db_rename_table('node_comment_statistics', 'comment_entity_statistics');
-  // Remove the statistics_node foreign key from entity_comment_statistics.
+
   // Add the entity_type and field_name columns to comment_entity_statistics.
   db_add_field('comment_entity_statistics', 'entity_type', array(
     'type' => 'varchar',
@@ -529,9 +529,13 @@ function comment_update_8005(&$sandbox) {
     'default' => 0,
     'description' => 'The entity_id to which this comment is a reply.',
   ));
+
   // Add indexes.
+  db_add_primary_key('comment_entity_statistics', array('entity_id', array('entity_type', 32), array('field_name',32)));
   db_add_index('comment_entity_statistics', 'last_comment_timestamp', array('last_comment_timestamp'));
-  db_add_primary_key('comment_entity_statistics', array('entity_id', 'entity_type', 'field_name'));
+  db_add_index('comment_entity_statistics', 'comment_count', array('comment_count'));
+  db_add_index('comment_entity_statistics', 'last_comment_uid', array('last_comment_uid'));
+
   $t = get_t();
   return $t('Updated database to reflect new comment structure');
 }