diff --git a/src/calibre/gui2/custom_column_widgets.py b/src/calibre/gui2/custom_column_widgets.py
index f6ed1e4d6f..f364638f37 100644
--- a/src/calibre/gui2/custom_column_widgets.py
+++ b/src/calibre/gui2/custom_column_widgets.py
@@ -41,7 +41,8 @@ class Base(object):
         val = self.gui_val
         val = self.normalize_ui_val(val)
         if val != self.initial_val:
-            self.db._set_custom(book_id, val, num=self.col_id, notify=notify)
+            self.db.set_custom(book_id, val, num=self.col_id, notify=notify,
+                               commit=False)
 
     def normalize_db_val(self, val):
         return val
@@ -304,8 +305,8 @@ class Series(Base):
                                                              num=self.col_id)
                 else:
                     s_index = None
-            self.db._set_custom(book_id, val, extra=s_index,
-                               num=self.col_id, notify=notify)
+            self.db.set_custom(book_id, val, extra=s_index,
+                               num=self.col_id, notify=notify, commit=False)
 
 widgets = {
         'bool' : Bool,
diff --git a/src/calibre/library/custom_columns.py b/src/calibre/library/custom_columns.py
index 60be09a193..4ba664dadc 100644
--- a/src/calibre/library/custom_columns.py
+++ b/src/calibre/library/custom_columns.py
@@ -412,10 +412,11 @@ class CustomColumns(object):
         self.conn.commit()
 
     def set_custom(self, id, val, label=None, num=None,
-                   append=False, notify=True, extra=None):
+                   append=False, notify=True, extra=None, commit=True):
         self._set_custom(id, val, label=label, num=num, append=append,
                          notify=notify, extra=extra)
-        self.conn.commit()
+        if commit:
+            self.conn.commit()
 
     def _set_custom(self, id_, val, label=None, num=None,
                    append=False, notify=True, extra=None):