diff --git a/program/lib/Roundcube/db/mysql.php b/program/lib/Roundcube/db/mysql.php
index aad6911ff..c9d5095c7 100644
--- a/program/lib/Roundcube/db/mysql.php
+++ b/program/lib/Roundcube/db/mysql.php
@@ -224,7 +224,7 @@ class rcube_db_mysql extends rcube_db
      * INSERT ... ON DUPLICATE KEY UPDATE (or equivalent).
      * When not supported by the engine we do UPDATE and INSERT.
      *
-     * @param string $table   Table name
+     * @param string $table   Table name (should be already passed via table_name() with quoting)
      * @param array  $keys    Hash array (column => value) of the unique constraint
      * @param array  $columns List of columns to update
      * @param array  $values  List of values to update (number of elements
@@ -235,7 +235,6 @@ class rcube_db_mysql extends rcube_db
      */
     public function insert_or_update($table, $keys, $columns, $values)
     {
-        $table   = $this->table_name($table, true);
         $columns = array_map(function($i) { return "`$i`"; }, $columns);
         $cols    = implode(', ', array_map(function($i) { return "`$i`"; }, array_keys($keys)));
         $cols   .= ', ' . implode(', ', $columns);
diff --git a/program/lib/Roundcube/db/pgsql.php b/program/lib/Roundcube/db/pgsql.php
index 8c66991c3..f8822dc18 100644
--- a/program/lib/Roundcube/db/pgsql.php
+++ b/program/lib/Roundcube/db/pgsql.php
@@ -195,7 +195,7 @@ class rcube_db_pgsql extends rcube_db
      * INSERT ... ON CONFLICT DO UPDATE.
      * When not supported by the engine we do UPDATE and INSERT.
      *
-     * @param string $table   Table name
+     * @param string $table   Table name (should be already passed via table_name() with quoting)
      * @param array  $keys    Hash array (column => value) of the unique constraint
      * @param array  $columns List of columns to update
      * @param array  $values  List of values to update (number of elements
@@ -211,7 +211,6 @@ class rcube_db_pgsql extends rcube_db
             return parent::insert_or_update($table, $keys, $columns, $values);
         }
 
-        $table   = $this->table_name($table, true);
         $columns = array_map([$this, 'quote_identifier'], $columns);
         $target  = implode(', ', array_map([$this, 'quote_identifier'], array_keys($keys)));
         $cols    = $target . ', ' . implode(', ', $columns);
diff --git a/program/lib/Roundcube/rcube_db.php b/program/lib/Roundcube/rcube_db.php
index 2ec03b479..284bb4bdd 100644
--- a/program/lib/Roundcube/rcube_db.php
+++ b/program/lib/Roundcube/rcube_db.php
@@ -576,7 +576,7 @@ class rcube_db
      * INSERT ... ON DUPLICATE KEY UPDATE (or equivalent).
      * When not supported by the engine we do UPDATE and INSERT.
      *
-     * @param string $table   Table name
+     * @param string $table   Table name (should be already passed via table_name() with quoting)
      * @param array  $keys    Hash array (column => value) of the unique constraint
      * @param array  $columns List of columns to update
      * @param array  $values  List of values to update (number of elements
@@ -587,7 +587,6 @@ class rcube_db
      */
     public function insert_or_update($table, $keys, $columns, $values)
     {
-        $table   = $this->table_name($table, true);
         $columns = array_map(function($i) { return "`$i`"; }, $columns);
         $sets    = array_map(function($i) { return "$i = ?"; }, $columns);
         $where   = $keys;