Fixed #10142 -- Added docs and an exploding error message to highlight an error present in the implementation of STDDEV_POP and VAR_POP in PostgreSQL 8.2-8.2.4 that will give incorrect answers (the database function mistakenly returns sample, rather than population deviation/variance). Thanks to Vinay Sajip <vinay_sajip@yahoo.co.uk> for the report, and Ian Kelly for pointing out the cause of the problem.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@9804 bcc190cf-cafb-0310-a4f2-bffc1f526a37

1 files changed, 9 insertions, 0 deletions

diff --git a/django/db/backends/__init__.py b/django/db/backends/__init__.py
index 33ec14e4d7..99f8f27ad9 100644
--- a/django/db/backends/__init__.py
+++ b/django/db/backends/__init__.py
@@ -398,6 +398,15 @@ class BaseDatabaseOperations(object):
         # Default to a float
         return float(value)
 
+    def check_aggregate_support(self, aggregate_func):
+        """Check that the backend supports the provided aggregate
+
+        This is used on specific backends to rule out known aggregates
+        that are known to have faulty implementations. If the named
+        aggregate function has a known problem, the backend should
+        raise NotImplemented.
+        """
+        pass
 
 class BaseDatabaseIntrospection(object):
     """