--- /dev/null
+<?php
+
+namespace Drupal\comment;
+
+use Drupal\Core\Entity\ContentEntityTypeInterface;
+use Drupal\Core\Entity\Sql\SqlContentEntityStorageSchema;
+use Drupal\Core\Field\FieldStorageDefinitionInterface;
+
+/**
+ * Defines the comment schema handler.
+ */
+class CommentStorageSchema extends SqlContentEntityStorageSchema {
+
+ /**
+ * {@inheritdoc}
+ */
+ protected function getEntitySchema(ContentEntityTypeInterface $entity_type, $reset = FALSE) {
+ $schema = parent::getEntitySchema($entity_type, $reset);
+
+ $schema['comment_field_data']['indexes'] += [
+ 'comment__status_pid' => ['pid', 'status'],
+ 'comment__num_new' => [
+ 'entity_id',
+ 'entity_type',
+ 'comment_type',
+ 'status',
+ 'created',
+ 'cid',
+ 'thread',
+ ],
+ 'comment__entity_langcode' => [
+ 'entity_id',
+ 'entity_type',
+ 'comment_type',
+ 'default_langcode',
+ ],
+ ];
+
+ return $schema;
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ protected function getSharedTableFieldSchema(FieldStorageDefinitionInterface $storage_definition, $table_name, array $column_mapping) {
+ $schema = parent::getSharedTableFieldSchema($storage_definition, $table_name, $column_mapping);
+ $field_name = $storage_definition->getName();
+
+ if ($table_name == 'comment_field_data') {
+ // Remove unneeded indexes.
+ unset($schema['indexes']['comment_field__pid__target_id']);
+ unset($schema['indexes']['comment_field__entity_id__target_id']);
+
+ switch ($field_name) {
+ case 'thread':
+ // Improves the performance of the comment__num_new index defined
+ // in getEntitySchema().
+ $schema['fields'][$field_name]['not null'] = TRUE;
+ break;
+
+ case 'created':
+ $this->addSharedTableFieldIndex($storage_definition, $schema, TRUE);
+ break;
+
+ case 'uid':
+ $this->addSharedTableFieldForeignKey($storage_definition, $schema, 'users', 'uid');
+ }
+ }
+
+ return $schema;
+ }
+
+}