diff --git a/search/classes/engine.php b/search/classes/engine.php
index 55c59637aa6..5854c025a72 100644
--- a/search/classes/engine.php
+++ b/search/classes/engine.php
@@ -394,6 +394,8 @@ abstract class engine {
      */
     public function optimize() {
         // Nothing by default.
+        mtrace('The ' . get_string('pluginname', $this->get_plugin_name()) .
+                ' search engine does not require automatic optimization.');
     }
 
     /**
diff --git a/search/engine/solr/classes/engine.php b/search/engine/solr/classes/engine.php
index a20d79e6b3f..0d433ab1152 100644
--- a/search/engine/solr/classes/engine.php
+++ b/search/engine/solr/classes/engine.php
@@ -1203,15 +1203,6 @@ class engine extends \core_search\engine {
         return (bool)$this->config->fileindexing;
     }
 
-    /**
-     * Defragments the index.
-     *
-     * @return void
-     */
-    public function optimize() {
-        $this->get_search_client()->optimize(1, true, false);
-    }
-
     /**
      * Deletes the specified document.
      *