Fixed #20420 -- Normalized query counts on Oracle.

This is achieved by inserting a fake entry in connection.queries when
not releasing a savepoint (since Oracle doesn't support that operation.)

Also removed the can_release_savepoints feature that was recently added,
but is superseded by this solution.

2 files changed, 12 insertions, 5 deletions

diff --git a/django/db/backends/__init__.py b/django/db/backends/__init__.py
index 39628e76fc..f4f2ba2fe0 100644
--- a/django/db/backends/__init__.py
+++ b/django/db/backends/__init__.py
@@ -74,6 +74,10 @@ class BaseDatabaseWrapper(object):
         self._thread_ident = thread.get_ident()
 
     @property
+    def queries_logged(self):
+        return self.use_debug_cursor or settings.DEBUG
+
+    @property
     def queries(self):
         if len(self.queries_log) == self.queries_log.maxlen:
             warnings.warn(
@@ -156,7 +160,7 @@ class BaseDatabaseWrapper(object):
         Creates a cursor, opening a connection if necessary.
         """
         self.validate_thread_sharing()
-        if self.use_debug_cursor or settings.DEBUG:
+        if self.queries_logged:
             cursor = self.make_debug_cursor(self._cursor())
         else:
             cursor = self.make_cursor(self._cursor())
@@ -493,7 +497,6 @@ class BaseDatabaseFeatures(object):
     can_return_id_from_insert = False
     has_bulk_insert = False
     uses_savepoints = False
-    can_release_savepoints = True
     can_combine_inserts_with_and_without_auto_increment_pk = False
 
     # If True, don't use integer foreign keys referring to, e.g., positive
diff --git a/django/db/backends/oracle/base.py b/django/db/backends/oracle/base.py
index f7790415db..b0b9a5f5a1 100644
--- a/django/db/backends/oracle/base.py
+++ b/django/db/backends/oracle/base.py
@@ -96,7 +96,6 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     needs_datetime_string_cast = False
     interprets_empty_strings_as_nulls = True
     uses_savepoints = True
-    can_release_savepoints = False
     has_select_for_update = True
     has_select_for_update_nowait = True
     can_return_id_from_insert = True
@@ -691,9 +690,14 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         "Returns a new instance of this backend's SchemaEditor"
         return DatabaseSchemaEditor(self, *args, **kwargs)
 
-    # Oracle doesn't support savepoint commits.  Ignore them.
+    # Oracle doesn't support releasing savepoints. But we fake them when query
+    # logging is enabled to keep query counts consistent with other backends.
     def _savepoint_commit(self, sid):
-        pass
+        if self.queries_logged:
+            self.queries_log.append({
+                'sql': '-- RELEASE SAVEPOINT %s (faked)' % self.ops.quote_name(sid),
+                'time': '0.000',
+            })
 
     def _set_autocommit(self, autocommit):
         with self.wrap_database_errors: