diff --git a/lib/ddl/database_manager.php b/lib/ddl/database_manager.php
index aa01e3cba19..41d7cda1af0 100644
--- a/lib/ddl/database_manager.php
+++ b/lib/ddl/database_manager.php
@@ -823,7 +823,20 @@ class database_manager {
             throw new ddl_exception('ddlunknownerror', null, 'add_index sql not generated');
         }
 
-        $this->execute_sql_arr($sqlarr, array($xmldb_table->getName()));
+        try {
+            $this->execute_sql_arr($sqlarr, array($xmldb_table->getName()));
+        } catch (ddl_change_structure_exception $e) {
+            // There could be a problem with the index length related to the row format of the table.
+            // If we are using utf8mb4 and the row format is 'compact' or 'redundant' then we need to change it over to
+            // 'compressed' or 'dynamic'.
+            if (method_exists($this->mdb, 'convert_table_row_format')) {
+                $this->mdb->convert_table_row_format($xmldb_table->getName());
+                $this->execute_sql_arr($sqlarr, array($xmldb_table->getName()));
+            } else {
+                // It's some other problem that we are currently not handling.
+                throw $e;
+            }
+        }
     }
 
     /**
diff --git a/lib/dml/mysqli_native_moodle_database.php b/lib/dml/mysqli_native_moodle_database.php
index 4227826b9d6..15926ee4b99 100644
--- a/lib/dml/mysqli_native_moodle_database.php
+++ b/lib/dml/mysqli_native_moodle_database.php
@@ -1917,4 +1917,18 @@ class mysqli_native_moodle_database extends moodle_database {
 
         return true;
     }
+
+    /**
+     * Converts a table to either 'Compressed' or 'Dynamic' row format.
+     *
+     * @param string $tablename Name of the table to convert to the new row format.
+     */
+    public function convert_table_row_format($tablename) {
+        $currentrowformat = $this->get_row_format($tablename);
+        if ($currentrowformat == 'Compact' || $currentrowformat == 'Redundant') {
+            $rowformat = ($this->is_compressed_row_format_supported(false)) ? "ROW_FORMAT=Compressed" : "ROW_FORMAT=Dynamic";
+            $prefix = $this->get_prefix();
+            $this->change_database_structure("ALTER TABLE {$prefix}$tablename $rowformat");
+        }
+    }
 }