Make path_to_location use bulk_write_operation for performance.

common/lib/xmodule/xmodule/modulestore/mixed.py

@@ -651,5 +651,8 @@ class MixedModuleStore(ModuleStoreDraftAndPublished, ModuleStoreWriteBase):
         If course_id is None, the default store is used.
         """
         store = self._get_modulestore_for_courseid(course_id)
-        with store.bulk_write_operations(course_id):
+        if hasattr(store, 'bulk_write_operations'):
+            with store.bulk_write_operations(course_id):
+                yield
+        else:
             yield

common/lib/xmodule/xmodule/modulestore/search.py

@@ -68,39 +68,41 @@ def path_to_location(modulestore, usage_key):
             newpath = (next_usage, path)
             queue.append((parent, newpath))
 
-    if not modulestore.has_item(usage_key):
-        raise ItemNotFoundError(usage_key)
+    # doesn't write but does multiple reads. bulk_write minimizes reads too
+    with modulestore.bulk_write_operations(usage_key.course_key):
+        if not modulestore.has_item(usage_key):
+            raise ItemNotFoundError(usage_key)
 
-    path = find_path_to_course()
-    if path is None:
-        raise NoPathToItem(usage_key)
+        path = find_path_to_course()
+        if path is None:
+            raise NoPathToItem(usage_key)
 
-    n = len(path)
-    course_id = path[0].course_key
-    # pull out the location names
-    chapter = path[1].name if n > 1 else None
-    section = path[2].name if n > 2 else None
-    # Figure out the position
-    position = None
+        n = len(path)
+        course_id = path[0].course_key
+        # pull out the location names
+        chapter = path[1].name if n > 1 else None
+        section = path[2].name if n > 2 else None
+        # Figure out the position
+        position = None
 
-    # This block of code will find the position of a module within a nested tree
-    # of modules. If a problem is on tab 2 of a sequence that's on tab 3 of a
-    # sequence, the resulting position is 3_2. However, no positional modules
-    # (e.g. sequential and videosequence) currently deal with this form of
-    # representing nested positions. This needs to happen before jumping to a
-    # module nested in more than one positional module will work.
-    if n > 3:
-        position_list = []
-        for path_index in range(2, n - 1):
-            category = path[path_index].block_type
-            if category == 'sequential' or category == 'videosequence':
-                section_desc = modulestore.get_item(path[path_index])
-                # this calls get_children rather than just children b/c old mongo includes private children
-                # in children but not in get_children
-                child_locs = [c.location for c in section_desc.get_children()]
-                # positions are 1-indexed, and should be strings to be consistent with
-                # url parsing.
-                position_list.append(str(child_locs.index(path[path_index + 1]) + 1))
-        position = "_".join(position_list)
+        # This block of code will find the position of a module within a nested tree
+        # of modules. If a problem is on tab 2 of a sequence that's on tab 3 of a
+        # sequence, the resulting position is 3_2. However, no positional modules
+        # (e.g. sequential and videosequence) currently deal with this form of
+        # representing nested positions. This needs to happen before jumping to a
+        # module nested in more than one positional module will work.
+        if n > 3:
+            position_list = []
+            for path_index in range(2, n - 1):
+                category = path[path_index].block_type
+                if category == 'sequential' or category == 'videosequence':
+                    section_desc = modulestore.get_item(path[path_index])
+                    # this calls get_children rather than just children b/c old mongo includes private children
+                    # in children but not in get_children
+                    child_locs = [c.location for c in section_desc.get_children()]
+                    # positions are 1-indexed, and should be strings to be consistent with
+                    # url parsing.
+                    position_list.append(str(child_locs.index(path[path_index + 1]) + 1))
+            position = "_".join(position_list)
 
-    return (course_id, chapter, section, position)
+        return (course_id, chapter, section, position)

common/lib/xmodule/xmodule/modulestore/tests/test_mixed_modulestore.py

@@ -717,7 +717,7 @@ class TestMixedModuleStore(unittest.TestCase):
     # TODO: LMS-11220: Document why draft send count is 5
     # TODO: LMS-11220: Document why draft find count is 18
     # TODO: LMS-11220: Document why split find count is 16
-    @ddt.data(('draft', [18, 5], 0), ('split', [16, 6], 0))
+    @ddt.data(('draft', [19, 5], 0), ('split', [2, 2], 0))
     @ddt.unpack
     def test_path_to_location(self, default_ms, num_finds, num_sends):
         """
@@ -736,7 +736,6 @@ class TestMixedModuleStore(unittest.TestCase):
                  (course_key, "Chapter_x", None, None)),
             )
 
-            mongo_store = self.store._get_modulestore_for_courseid(self._course_key_from_string(self.MONGO_COURSEID))
             for location, expected in should_work:
                 with check_mongo_calls(num_finds.pop(0), num_sends):
                     self.assertEqual(path_to_location(self.store, location), expected)