Optionally optimize table truncation supplying a low level query stat…

…ement in settings.

MANIFEST.in

@@ -1,3 +1,4 @@
 include LICENSE
 include README.rst
+recursive-include easyaudit/static *
 recursive-include easyaudit/templates *

easyaudit/admin_helpers.py

@@ -9,6 +9,7 @@
 from django.contrib import messages
 from django.conf.urls import url
 from django.utils.safestring import mark_safe
+from . import settings
 
 
 class EasyAuditModelAdmin(admin.ModelAdmin):
@@ -51,6 +52,16 @@ def purge_objects(self, request):
         This action first displays a confirmation page;
         next, it deletes all objects and redirects back to the change list.
         """
+
+        def truncate_table(model):
+            if settings.TRUNCATE_TABLE_SQL_STATEMENT:
+                from django.db import connection
+                sql = settings.TRUNCATE_TABLE_SQL_STATEMENT.format(db_table=model._meta.db_table)
+                cursor = connection.cursor()
+                cursor.execute(sql)
+            else:
+                model.objects.all().delete()
+
         modeladmin = self
         opts = modeladmin.model._meta
 
@@ -65,8 +76,9 @@ def purge_objects(self, request):
         if request.method == 'POST':
             if 'btn-confirm' in request.POST:
                 try:
-                    modeladmin.model.objects.all().delete()
-                    modeladmin.message_user(request, _("Successfully removed all objects"), messages.SUCCESS);
+                    n = modeladmin.model.objects.count()
+                    truncate_table(modeladmin.model)
+                    modeladmin.message_user(request, _("Successfully removed %d rows" % n), messages.SUCCESS);
                 except Exception as e:
                     modeladmin.message_user(request, _(u'ERROR') + ': %r' % e, messages.ERROR)
             else:

easyaudit/settings.py

@@ -72,4 +72,14 @@ def get_model_list(class_list):
 for idx, callback in enumerate(CRUD_DIFFERENCE_CALLBACKS):
     if not callable(callback):  # keep as is if it is callable
         CRUD_DIFFERENCE_CALLBACKS[idx] = getattr(import_module('.'.join(callback.split('.')[:-1])),
-                                                 callback.split('.')[-1], None)
+                                                 callback.split('.')[-1], None)
+
+# Purge table optimization:
+# If TRUNCATE_TABLE_SQL_STATEMENT is not empty, we use it as custom sql statement
+# to speed up table truncation bypassing ORM, i.e.:
+#   DJANGO_EASY_AUDIT_TRUNCATE_TABLE_SQL_STATEMENT = "TRUNCATE TABLE `{db_table}`"  # for Postgresql
+# Else we use Django Orm as follows:
+#   model.objects.all().delete()
+# which is however much costly when many rows are involved
+TRUNCATE_TABLE_SQL_STATEMENT = getattr(settings, 'DJANGO_EASY_AUDIT_TRUNCATE_TABLE_SQL_STATEMENT', '')
+