diff --git a/python/plugins/db_manager/db_plugins/data_model.py b/python/plugins/db_manager/db_plugins/data_model.py
index 6ac44fa4545..61be0f841c8 100644
--- a/python/plugins/db_manager/db_plugins/data_model.py
+++ b/python/plugins/db_manager/db_plugins/data_model.py
@@ -152,11 +152,8 @@ class SqlResultModelAsync(QObject):
 
     done = pyqtSignal()
 
-    def __init__(self, db, sql, parent=None):
+    def __init__(self):
         QObject.__init__(self)
-        self.db = db
-        self.sql = sql
-        self.parent = parent
         self.error = BaseError('')
         self.status = None
         self.model = None
@@ -164,7 +161,7 @@ class SqlResultModelAsync(QObject):
 
     def cancel(self):
         if self.task:
-            self.task.cancelQuery()
+            self.task.cancel()
 
     def modelDone(self):
         if self.task:
diff --git a/python/plugins/db_manager/db_plugins/postgis/data_model.py b/python/plugins/db_manager/db_plugins/postgis/data_model.py
index 8510a73a77b..c8707bc2e39 100644
--- a/python/plugins/db_manager/db_plugins/postgis/data_model.py
+++ b/python/plugins/db_manager/db_plugins/postgis/data_model.py
@@ -97,15 +97,15 @@ class PGSqlResultModelTask(SqlResultModelTask):
             return False
         return True
 
-    def cancelQuery(self):
+    def cancel(self):
         self.db.connector.cancel()
-        self.cancel()
+        SqlResultModelTask.cancel(self)
 
 
 class PGSqlResultModelAsync(SqlResultModelAsync):
 
     def __init__(self, db, sql, parent):
-        SqlResultModelAsync.__init__(self, db, sql, parent)
+        SqlResultModelAsync.__init__(self)
 
         self.task = PGSqlResultModelTask(db, sql, parent)
         self.task.taskCompleted.connect(self.modelDone)
diff --git a/python/plugins/db_manager/db_plugins/spatialite/data_model.py b/python/plugins/db_manager/db_plugins/spatialite/data_model.py
index fca23c3f3f8..afb05aa56bc 100644
--- a/python/plugins/db_manager/db_plugins/spatialite/data_model.py
+++ b/python/plugins/db_manager/db_plugins/spatialite/data_model.py
@@ -87,16 +87,16 @@ class SLSqlResultModelTask(SqlResultModelTask):
 
         return True
 
-    def cancelQuery(self):
+    def cancel(self):
         if self.clone:
             self.clone.connector.cancel()
-        self.cancel()
+        SqlResultModelTask.cancel(self)
 
 
 class SLSqlResultModelAsync(SqlResultModelAsync):
 
     def __init__(self, db, sql, parent):
-        SqlResultModelAsync.__init__(self, db, sql, parent)
+        SqlResultModelAsync.__init__(self)
 
         self.task = SLSqlResultModelTask(db, sql, parent)
         self.task.taskCompleted.connect(self.modelDone)
diff --git a/python/plugins/db_manager/db_plugins/vlayers/data_model.py b/python/plugins/db_manager/db_plugins/vlayers/data_model.py
index a5112363cc0..0089fb84e5f 100644
--- a/python/plugins/db_manager/db_plugins/vlayers/data_model.py
+++ b/python/plugins/db_manager/db_plugins/vlayers/data_model.py
@@ -97,15 +97,15 @@ class LSqlResultModelTask(SqlResultModelTask):
             return False
         return True
 
-    def cancelQuery(self):
+    def cancel(self):
         self.subtask.cancel()
-        self.cancel()
+        SqlResultModelTask.cancel(self)
 
 
 class LSqlResultModelAsync(SqlResultModelAsync):
 
     def __init__(self, db, sql, parent=None):
-        SqlResultModelAsync.__init__(self, db, sql, parent)
+        SqlResultModelAsync.__init__(self)
 
         self.task = LSqlResultModelTask(db, sql, parent)
         self.task.taskCompleted.connect(self.modelDone)
diff --git a/python/plugins/db_manager/dlg_cancel_task_query.py b/python/plugins/db_manager/dlg_cancel_task_query.py
index b4583d07341..3a98b69440f 100644
--- a/python/plugins/db_manager/dlg_cancel_task_query.py
+++ b/python/plugins/db_manager/dlg_cancel_task_query.py
@@ -58,8 +58,8 @@ class DlgCancelTaskQuery(QDialog, Ui_Dialog):
         self.mGif.start()
         self.mCancelButton.setEnabled(True)
         self.mLabel.setText("Executing SQL...")
-        super(QDialog, self).show()
+        QDialog.show(self)
 
     def hide(self):
         self.mGif.stop()
-        super(QDialog, self).hide()
+        QDialog.hide(self)