From c07f6405b988e18ca3e9c8b19faea780d7ec649a Mon Sep 17 00:00:00 2001
From: sanfordstudent <sstudent@edx.org>
Date: Thu, 12 Jan 2017 10:54:35 -0500
Subject: [PATCH] Revert "add index for modified to course and subsection
 grades"

---
 .../migrations/0009_auto_20170111_1507.py     | 22 -------------------
 lms/djangoapps/grades/models.py               | 11 ----------
 2 files changed, 33 deletions(-)
 delete mode 100644 lms/djangoapps/grades/migrations/0009_auto_20170111_1507.py

diff --git a/lms/djangoapps/grades/migrations/0009_auto_20170111_1507.py b/lms/djangoapps/grades/migrations/0009_auto_20170111_1507.py
deleted file mode 100644
index d71c45a811..0000000000
--- a/lms/djangoapps/grades/migrations/0009_auto_20170111_1507.py
+++ /dev/null
@@ -1,22 +0,0 @@
-# -*- coding: utf-8 -*-
-from __future__ import unicode_literals
-
-from django.db import migrations, models
-
-
-class Migration(migrations.Migration):
-
-    dependencies = [
-        ('grades', '0008_persistentsubsectiongrade_first_attempted'),
-    ]
-
-    operations = [
-        migrations.AlterIndexTogether(
-            name='persistentcoursegrade',
-            index_together=set([('passed_timestamp', 'course_id'), ('modified', 'course_id')]),
-        ),
-        migrations.AlterIndexTogether(
-            name='persistentsubsectiongrade',
-            index_together=set([('modified', 'course_id', 'usage_key')]),
-        ),
-    ]
diff --git a/lms/djangoapps/grades/models.py b/lms/djangoapps/grades/models.py
index e53ca6f674..e95cda16e0 100644
--- a/lms/djangoapps/grades/models.py
+++ b/lms/djangoapps/grades/models.py
@@ -253,14 +253,6 @@ class PersistentSubsectionGrade(DeleteGradesMixin, TimeStampedModel):
             # * Course staff can see all grades for a course using (course_id,)
             ('course_id', 'user_id', 'usage_key'),
         ]
-        # Allows querying in the following ways:
-        # (modified): find all the grades updated within a certain timespan
-        # (modified, course_id): find all the grades updated within a timespan for a certain course
-        # (modified, course_id, usage_key): find all the grades updated within a timespan for a subsection
-        #   in a course
-        index_together = [
-            ('modified', 'course_id', 'usage_key')
-        ]
 
     # primary key will need to be large for this table
     id = UnsignedBigIntAutoField(primary_key=True)  # pylint: disable=invalid-name
@@ -510,14 +502,11 @@ class PersistentCourseGrade(DeleteGradesMixin, TimeStampedModel):
         # (course_id) for instructors to see all course grades, implicitly created via the unique_together constraint
         # (user_id) for course dashboard; explicitly declared as an index below
         # (passed_timestamp, course_id) for tracking when users first earned a passing grade.
-        # (modified): find all the grades updated within a certain timespan
-        # (modified, course_id): find all the grades updated within a certain timespan for a course
         unique_together = [
             ('course_id', 'user_id'),
         ]
         index_together = [
             ('passed_timestamp', 'course_id'),
-            ('modified', 'course_id')
         ]
 
     # primary key will need to be large for this table