Ticket #17956: explicit_cursor_closing.patch

django/db/models/sql/compiler.py

@@ -738 +738 @@
             return cursor
         if result_type == SINGLE:
             if self.query.ordering_aliases:
-                return cursor.fetchone()[:-len(self.query.ordering_aliases)]
-            return cursor.fetchone()
+                r = cursor.fetchone()[:-len(self.query.ordering_aliases)]
+            else:
+                r = cursor.fetchone()
+            cursor.close()
+            return r
 
         # The MULTI case.
         if self.query.ordering_aliases:
             result = order_modified_iter(cursor, len(self.query.ordering_aliases),
                     self.connection.features.empty_fetchmany_value)
         else:
-            result = iter((lambda: cursor.fetchmany(GET_ITERATOR_CHUNK_SIZE)),
+            result = not_modified_iter(cursor,
                     self.connection.features.empty_fetchmany_value)
+
         if not self.connection.features.can_use_chunked_reads:
             # If we are using non-chunked reads, we return the same data
             # structure as normally, but ensure it is all read into memory
@@ -789 +793 @@
     def execute_sql(self, return_id=False):
         self.return_id = return_id
         cursor = super(SQLInsertCompiler, self).execute_sql(None)
-        if not (return_id and cursor):
+        if not cursor:
             return
-        if self.connection.features.can_return_id_from_insert:
-            return self.connection.ops.fetch_returned_insert_id(cursor)
-        return self.connection.ops.last_insert_id(cursor,
-                self.query.model._meta.db_table, self.query.model._meta.pk.column)
+        r = None
+        if return_id:
+            if self.connection.features.can_return_id_from_insert:
+                r = self.connection.ops.fetch_returned_insert_id(cursor)
+            else:
+                r = self.connection.ops.last_insert_id(cursor,
+                    self.query.model._meta.db_table, self.query.model._meta.pk.column)
+        cursor.close()
+        return r
 
 
 class SQLDeleteCompiler(SQLCompiler):
@@ -869 +878 @@
         cursor = super(SQLUpdateCompiler, self).execute_sql(result_type)
         rows = cursor and cursor.rowcount or 0
         is_empty = cursor is None
+        if cursor:
+            cursor.close()
         del cursor
         for query in self.query.get_related_updates():
             aux_rows = query.get_compiler(self.using).execute_sql(result_type)
@@ -980 +991 @@
     for rows in iter((lambda: cursor.fetchmany(GET_ITERATOR_CHUNK_SIZE)),
             sentinel):
         yield [r[:-trim] for r in rows]
+    cursor.close()
+
+def not_modified_iter(cursor, sentinel):
+    """
+    Yields blocks of rows from a cursor. We use this iterator in usual
+    case - just to close the cursor at appropriate time.
+    """
+    for rows in iter((lambda: cursor.fetchmany(GET_ITERATOR_CHUNK_SIZE)),
+            sentinel):
+        yield [r[:] for r in rows]
+    cursor.close()