diff --git a/core/modules/comment/comment.install b/core/modules/comment/comment.install
index 391a255..fc859ba 100644
--- a/core/modules/comment/comment.install
+++ b/core/modules/comment/comment.install
@@ -5,6 +5,7 @@
  * Install, update and uninstall functions for the Comment module.
  */
 
+use Drupal\Core\Entity\EntityTypeInterface;
 use Drupal\field\Entity\FieldConfig;
 
 /**
@@ -48,7 +49,7 @@ function comment_schema() {
         'type' => 'varchar',
         'not null' => TRUE,
         'default' => 'node',
-        'length' => 255,
+        'length' => EntityTypeInterface::ID_MAX_LENGTH,
         'description' => 'The entity_type of the entity to which this comment is a reply.',
       ),
       'field_name' => array(
diff --git a/core/modules/comment/comment.module b/core/modules/comment/comment.module
index 8930d76..5e21a9b 100644
--- a/core/modules/comment/comment.module
+++ b/core/modules/comment/comment.module
@@ -206,7 +206,7 @@ function comment_field_config_insert(FieldConfigInterface $field) {
 function comment_field_instance_config_delete(FieldInstanceConfigInterface $instance) {
   if ($instance->getType() == 'comment') {
     // Delete all comments that used by the entity bundle.
-    $comments = db_query("SELECT cid FROM {comment} WHERE entity_type = :entity_type AND field_name = :field_name", array(
+    $comments = db_query("SELECT cid FROM {comment_field_data} WHERE entity_type = :entity_type AND field_name = :field_name", array(
       ':entity_type' => $instance->getEntityTypeId(),
       ':field_name' => $instance->getName(),
     ))->fetchCol();
@@ -276,7 +276,7 @@ function comment_new_page_count($num_comments, $new_replies, ContentEntityInterf
     // thread with a new comment.
 
     // 1. Find all the threads with a new comment.
-    $unread_threads_query = db_select('comment')
+    $unread_threads_query = db_select('comment_field_data')
       ->fields('comment', array('thread'))
       ->condition('entity_id', $entity->id())
       ->condition('entity_type', $entity->getEntityTypeId())
@@ -300,7 +300,7 @@ function comment_new_page_count($num_comments, $new_replies, ContentEntityInterf
     $first_thread = substr($first_thread, 0, -1);
 
     // Find the number of the first comment of the first unread thread.
-    $count = db_query('SELECT COUNT(*) FROM {comment} WHERE entity_id = :entity_id
+    $count = db_query('SELECT COUNT(*) FROM {comment_field_data} WHERE entity_id = :entity_id
                       AND entity_type = :entity_type
                       AND field_name = :field_name
                       AND status = :status AND SUBSTRING(thread, 1, (LENGTH(thread) - 1)) < :thread', array(
@@ -605,7 +605,7 @@ function comment_add(EntityInterface $entity, $field_name = 'comment', $pid = NU
  * to consider the trailing "/" so we use a substring only.
  */
 function comment_get_thread(EntityInterface $entity, $field_name, $mode, $comments_per_page, $pager_id = 0) {
-  $query = db_select('comment', 'c')
+  $query = db_select('comment_field_data', 'c')
     ->extend('Drupal\Core\Database\Query\PagerSelectExtender');
   if ($pager_id) {
     $query->element($pager_id);
@@ -622,7 +622,7 @@ function comment_get_thread(EntityInterface $entity, $field_name, $mode, $commen
     ->addMetaData('field_name', $field_name)
     ->limit($comments_per_page);
 
-  $count_query = db_select('comment', 'c');
+  $count_query = db_select('comment_field_data', 'c');
   $count_query->addExpression('COUNT(*)');
   $count_query
     ->condition('c.entity_id', $entity->id())
@@ -1065,7 +1065,7 @@ function comment_num_new($entity_id, $entity_type, $field_name = NULL, $timestam
     $timestamp = ($timestamp > HISTORY_READ_LIMIT ? $timestamp : HISTORY_READ_LIMIT);
 
     // Use the timestamp to retrieve the number of new comments.
-    $query = db_select('comment', 'c');
+    $query = db_select('comment_field_data', 'c');
     $query->addExpression('COUNT(cid)');
     $query->condition('c.entity_type', $entity_type)
       ->condition('c.entity_id', $entity_id)
@@ -1104,8 +1104,8 @@ function comment_num_new($entity_id, $entity_type, $field_name = NULL, $timestam
 function comment_get_display_ordinal($cid, FieldDefinitionInterface $field_definition) {
   // Count how many comments (c1) are before $cid (c2) in display order. This is
   // the 0-based display ordinal.
-  $query = db_select('comment', 'c1');
-  $query->innerJoin('comment', 'c2', 'c2.entity_id = c1.entity_id AND c2.entity_type = c1.entity_type AND c2.field_name = c1.field_name');
+  $query = db_select('comment_field_data', 'c1');
+  $query->innerJoin('comment_field_data', 'c2', 'c2.entity_id = c1.entity_id AND c2.entity_type = c1.entity_type AND c2.field_name = c1.field_name');
   $query->addExpression('COUNT(*)', 'count');
   $query->condition('c2.cid', $cid);
   if (!user_access('administer comments')) {
diff --git a/core/modules/comment/src/CommentStatistics.php b/core/modules/comment/src/CommentStatistics.php
index fbbdff4..afb4d56 100644
--- a/core/modules/comment/src/CommentStatistics.php
+++ b/core/modules/comment/src/CommentStatistics.php
@@ -179,7 +179,7 @@ public function update(CommentInterface $comment) {
       return;
     }
 
-    $query = $this->database->select('comment', 'c');
+    $query = $this->database->select('comment_field_data', 'c');
     $query->addExpression('COUNT(cid)');
     $count = $query->condition('c.entity_id', $comment->getCommentedEntityId())
       ->condition('c.entity_type', $comment->getCommentedEntityTypeId())
@@ -190,7 +190,7 @@ public function update(CommentInterface $comment) {
 
     if ($count > 0) {
       // Comments exist.
-      $last_reply = $this->database->select('comment', 'c')
+      $last_reply = $this->database->select('comment_field_data', 'c')
         ->fields('c', array('cid', 'name', 'changed', 'uid'))
         ->condition('c.entity_id', $comment->getCommentedEntityId())
         ->condition('c.entity_type', $comment->getCommentedEntityTypeId())
diff --git a/core/modules/comment/src/CommentStorage.php b/core/modules/comment/src/CommentStorage.php
index f463d0a..c98d269 100644
--- a/core/modules/comment/src/CommentStorage.php
+++ b/core/modules/comment/src/CommentStorage.php
@@ -69,7 +69,7 @@ public function updateEntityStatistics(CommentInterface $comment) {
    * {@inheritdoc}
    */
   public function getMaxThread(EntityInterface $comment) {
-    $query = $this->database->select('comment', 'c')
+    $query = $this->database->select('comment_field_data', 'c')
       ->condition('entity_id', $comment->getCommentedEntityId())
       ->condition('field_name', $comment->getFieldName())
       ->condition('entity_type', $comment->getCommentedEntityTypeId());
@@ -82,7 +82,7 @@ public function getMaxThread(EntityInterface $comment) {
    * {@inheritdoc}
    */
   public function getMaxThreadPerThread(EntityInterface $comment) {
-    $query = $this->database->select('comment', 'c')
+    $query = $this->database->select('comment_field_data', 'c')
       ->condition('entity_id', $comment->getCommentedEntityId())
       ->condition('field_name', $comment->getFieldName())
       ->condition('entity_type', $comment->getCommentedEntityTypeId())
@@ -96,7 +96,7 @@ public function getMaxThreadPerThread(EntityInterface $comment) {
    * {@inheritdoc}
    */
   public function getChildCids(array $comments) {
-    return $this->database->select('comment', 'c')
+    return $this->database->select('comment_field_data', 'c')
       ->fields('c', array('cid'))
       ->condition('pid', array_keys($comments))
       ->execute()
@@ -111,19 +111,16 @@ public function getSchema() {
 
     // Marking the respective fields as NOT NULL makes the indexes more
     // performant.
-    $schema['comment']['fields']['pid']['not null'] = TRUE;
-    $schema['comment']['fields']['status']['not null'] = TRUE;
-    $schema['comment']['fields']['entity_id']['not null'] = TRUE;
-    $schema['comment']['fields']['created']['not null'] = TRUE;
-    $schema['comment']['fields']['thread']['not null'] = TRUE;
-
-    unset($schema['comment']['indexes']['field__pid']);
-    unset($schema['comment']['indexes']['field__entity_id']);
-    $schema['comment']['indexes'] += array(
+    $schema['comment_field_data']['fields']['created']['not null'] = TRUE;
+    $schema['comment_field_data']['fields']['thread']['not null'] = TRUE;
+
+    unset($schema['comment_field_data']['indexes']['comment_field__pid__target_id']);
+    unset($schema['comment_field_data']['indexes']['comment_field__entity_id__target_id']);
+    $schema['comment_field_data']['indexes'] += array(
       'comment__status_pid' => array('pid', 'status'),
       'comment__num_new' => array(
         'entity_id',
-        array('entity_type', 32),
+        'entity_type',
         'comment_type',
         'status',
         'created',
@@ -132,13 +129,13 @@ public function getSchema() {
       ),
       'comment__entity_langcode' => array(
         'entity_id',
-        array('entity_type', 32),
+        'entity_type',
         'comment_type',
-        'langcode',
+        'default_langcode',
       ),
       'comment__created' => array('created'),
     );
-    $schema['comment']['foreign keys'] += array(
+    $schema['comment_field_data']['foreign keys'] += array(
       'comment__author' => array(
         'table' => 'users',
         'columns' => array('uid' => 'uid'),
@@ -152,7 +149,7 @@ public function getSchema() {
    * {@inheritdoc}
    */
   public function getUnapprovedCount() {
-    return  $this->database->select('comment', 'c')
+    return  $this->database->select('comment_field_data', 'c')
       ->condition('status', CommentInterface::NOT_PUBLISHED, '=')
       ->countQuery()
       ->execute()
diff --git a/core/modules/comment/src/Entity/Comment.php b/core/modules/comment/src/Entity/Comment.php
index 1773b31..3294c88 100644
--- a/core/modules/comment/src/Entity/Comment.php
+++ b/core/modules/comment/src/Entity/Comment.php
@@ -34,6 +34,7 @@
  *     "translation" = "Drupal\comment\CommentTranslationHandler"
  *   },
  *   base_table = "comment",
+ *   data_table = "comment_field_data",
  *   uri_callback = "comment_uri",
  *   fieldable = TRUE,
  *   translatable = TRUE,
@@ -228,6 +229,7 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
     $fields['subject'] = FieldDefinition::create('string')
       ->setLabel(t('Subject'))
       ->setDescription(t('The comment title or subject.'))
+      ->setTranslatable(TRUE)
       ->setSetting('max_length', 64);
 
     $fields['uid'] = FieldDefinition::create('entity_reference')
@@ -279,7 +281,8 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
 
     $fields['entity_type'] = FieldDefinition::create('string')
       ->setLabel(t('Entity type'))
-      ->setDescription(t('The entity type to which this comment is attached.'));
+      ->setDescription(t('The entity type to which this comment is attached.'))
+      ->setSetting('max_length', EntityTypeInterface::ID_MAX_LENGTH);
 
     $fields['comment_type'] = FieldDefinition::create('entity_reference')
       ->setLabel(t('Comment Type'))
@@ -289,7 +292,7 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
     $fields['field_name'] = FieldDefinition::create('string')
       ->setLabel(t('Comment field name'))
       ->setDescription(t('The field name through which this comment was added.'))
-      ->setSetting('max_length', 32);
+      ->setSetting('max_length', FieldConfig::NAME_MAX_LENGTH);
 
     return $fields;
   }
diff --git a/core/modules/comment/src/Plugin/views/field/NodeNewComments.php b/core/modules/comment/src/Plugin/views/field/NodeNewComments.php
index 5ccf4e2..f7e0436 100644
--- a/core/modules/comment/src/Plugin/views/field/NodeNewComments.php
+++ b/core/modules/comment/src/Plugin/views/field/NodeNewComments.php
@@ -118,7 +118,7 @@ public function preRender(&$values) {
     }
 
     if ($nids) {
-      $result = $this->database->query("SELECT n.nid, COUNT(c.cid) as num_comments FROM {node} n INNER JOIN {comment} c ON n.nid = c.entity_id AND c.entity_type = 'node'
+      $result = $this->database->query("SELECT n.nid, COUNT(c.cid) as num_comments FROM {node} n INNER JOIN {comment_field_data} c ON n.nid = c.entity_id AND c.entity_type = 'node'
         LEFT JOIN {history} h ON h.nid = n.nid AND h.uid = :h_uid WHERE n.nid IN (:nids)
         AND c.changed > GREATEST(COALESCE(h.timestamp, :timestamp), :timestamp) AND c.status = :status GROUP BY n.nid", array(
         ':status' => CommentInterface::PUBLISHED,
diff --git a/core/modules/comment/src/Tests/CommentLanguageTest.php b/core/modules/comment/src/Tests/CommentLanguageTest.php
index aa3d5aa..cb33ca1 100644
--- a/core/modules/comment/src/Tests/CommentLanguageTest.php
+++ b/core/modules/comment/src/Tests/CommentLanguageTest.php
@@ -117,7 +117,7 @@ function testCommentLanguage() {
         $this->drupalPostForm(NULL, $edit, t('Save'));
 
         // Check that comment language matches the current content language.
-        $cid = db_select('comment', 'c')
+        $cid = db_select('comment_field_data', 'c')
           ->fields('c', array('cid'))
           ->condition('entity_id', $node->id())
           ->condition('entity_type', 'node')
diff --git a/core/modules/forum/src/ForumIndexStorage.php b/core/modules/forum/src/ForumIndexStorage.php
index d732806..e7ba619 100644
--- a/core/modules/forum/src/ForumIndexStorage.php
+++ b/core/modules/forum/src/ForumIndexStorage.php
@@ -96,14 +96,14 @@ public function update(NodeInterface $node) {
    */
   public function updateIndex(NodeInterface $node) {
     $nid = $node->id();
-    $count = $this->database->query("SELECT COUNT(cid) FROM {comment} c INNER JOIN {forum_index} i ON c.entity_id = i.nid WHERE c.entity_id = :nid AND c.field_name = 'comment_forum' AND c.entity_type = 'node' AND c.status = :status", array(
+    $count = $this->database->query("SELECT COUNT(cid) FROM {comment_field_data} c INNER JOIN {forum_index} i ON c.entity_id = i.nid WHERE c.entity_id = :nid AND c.field_name = 'comment_forum' AND c.entity_type = 'node' AND c.status = :status", array(
       ':nid' => $nid,
       ':status' => CommentInterface::PUBLISHED,
     ))->fetchField();
 
     if ($count > 0) {
       // Comments exist.
-      $last_reply = $this->database->queryRange("SELECT cid, name, created, uid FROM {comment} WHERE entity_id = :nid AND field_name = 'comment_forum' AND entity_type = 'node' AND status = :status ORDER BY cid DESC", 0, 1, array(
+      $last_reply = $this->database->queryRange("SELECT cid, name, created, uid FROM {comment_field_data} WHERE entity_id = :nid AND field_name = 'comment_forum' AND entity_type = 'node' AND status = :status ORDER BY cid DESC", 0, 1, array(
         ':nid' => $nid,
         ':status' => CommentInterface::PUBLISHED,
       ))->fetchObject();
diff --git a/core/modules/tracker/tracker.module b/core/modules/tracker/tracker.module
index 9195600..6594d24 100644
--- a/core/modules/tracker/tracker.module
+++ b/core/modules/tracker/tracker.module
@@ -81,7 +81,7 @@ function tracker_cron() {
         ))
         ->execute();
 
-      $query = db_select('comment', 'c', array('target' => 'replica'));
+      $query = db_select('comment_field_data', 'c', array('target' => 'replica'));
       // Force PostgreSQL to do an implicit cast by adding 0.
       $query->addExpression('0 + :changed', 'changed', array(':changed' => $changed));
       $query->addField('c', 'status', 'published');
@@ -291,7 +291,7 @@ function _tracker_calculate_changed($nid) {
   // @todo This should be actually filtering on the desired language and just
   //   fall back to the default language.
   $changed = db_query('SELECT changed FROM {node_field_data} WHERE nid = :nid AND default_langcode = 1 ORDER BY changed DESC', array(':nid' => $nid), array('target' => 'replica'))->fetchField();
-  $latest_comment = db_query_range("SELECT cid, changed FROM {comment} WHERE entity_type = 'node' AND entity_id = :nid AND status = :status ORDER BY changed DESC", 0, 1, array(
+  $latest_comment = db_query_range("SELECT cid, changed FROM {comment_field_data} WHERE entity_type = 'node' AND entity_id = :nid AND status = :status ORDER BY changed DESC", 0, 1, array(
     ':nid' => $nid,
     ':status' => CommentInterface::PUBLISHED,
   ), array('target' => 'replica'))->fetchObject();
@@ -324,7 +324,7 @@ function _tracker_remove($nid, $uid = NULL, $changed = NULL) {
     // Or if they have commented on the node.
     if (!$keep_subscription) {
       // Check if the user has commented at least once on the given nid.
-      $keep_subscription = db_query_range("SELECT COUNT(*) FROM {comment} WHERE entity_type = 'node' AND entity_id = :nid AND uid = :uid AND status = :status", 0, 1, array(
+      $keep_subscription = db_query_range("SELECT COUNT(*) FROM {comment_field_data} WHERE entity_type = 'node' AND entity_id = :nid AND uid = :uid AND status = :status", 0, 1, array(
         ':nid' => $nid,
         ':uid' => $uid,
         ':status' => CommentInterface::PUBLISHED,