prevent count queries from re-executing due to sort/page options

webgrid/__init__.py

@@ -1210,7 +1210,7 @@ def set_sort(self, *args):
             that key, prepend with a "-".
             E.g. `grid.set_sort('author', '-post_date')`
         """
-        self.clear_record_cache()
+        self.clear_record_cache(preserve_count=True)
         self.order_by = []
 
         for key in args:
@@ -1232,14 +1232,19 @@ def set_paging(self, per_page, on_page):
             per_page (int): Record limit for each page.
             on_page (int): With `per_page`, computes the offset.
         """
-        self.clear_record_cache()
+        self.clear_record_cache(preserve_count=True)
         self.per_page = per_page
         self.on_page = on_page
 
-    def clear_record_cache(self):
+    def clear_record_cache(self, preserve_count=False):
         """Reset records and record count cached from previous queries.
+
+        Args:
+            preserve_count (bool): Direct grid to retain count of records, effectively removing
+            only the table of records itself.
         """
-        self._record_count = None
+        if not preserve_count:
+            self._record_count = None
         self._records = None
 
     @property

webgrid/tests/test_unit.py

@@ -358,6 +358,33 @@ def test_record_count(self, m_debug):
         for idx, call in enumerate(m_debug.call_args_list):
             assert re.match(expected[idx], call[0][0])
 
+    @mock.patch('logging.Logger.debug')
+    def test_record_count_preserved_during_sort(self, m_debug):
+        g = self.TG()
+        assert g.record_count == 5
+        assert m_debug.call_count == 3
+        g.set_sort('firstname')
+        assert g.record_count == 5
+        assert m_debug.call_count == 3
+
+    @mock.patch('logging.Logger.debug')
+    def test_record_count_preserved_during_paging(self, m_debug):
+        g = self.TG()
+        assert g.record_count == 5
+        assert m_debug.call_count == 3
+        g.set_paging(25, 1)
+        assert g.record_count == 5
+        assert m_debug.call_count == 3
+
+    @mock.patch('logging.Logger.debug')
+    def test_record_count_cleared_during_filter(self, m_debug):
+        g = self.KeyGrid()
+        g.record_count
+        assert m_debug.call_count == 3
+        g.set_filter('id', 'eq', '5')
+        g.record_count
+        assert m_debug.call_count == 6
+
     def test_column_iterators_for_rendering(self):
         class TG(Grid):
             Column('C1', Person.firstname)