the order of `order_by`

order_bh.md

I used a paying_for_college query of notifications as a test of where to use an order_by clause.

We have 193K notifications, unorderd by default. 179K of them have '1' in their oid field.

from paying_for_college.models import Notification

nosort = Notification.objects.filter(oid__contains='1')
first = Notification.objects.order_by('timestamp').filter(oid__contains='1')
last = Notification.objects.filter(oid__contains='1').order_by('timestamp')

str(nosort.query)

SELECT "paying_for_college_notification"."id", "paying_for_college_notification"."url", 
"paying_for_college_notification"."institution_id", "paying_for_college_notification"."oid", 
"paying_for_college_notification"."timestamp", "paying_for_college_notification"."errors", 
"paying_for_college_notification"."emails", "paying_for_college_notification"."sent", 
"paying_for_college_notification"."log" 
FROM "paying_for_college_notification" 
WHERE "paying_for_college_notification"."oid"::text LIKE %1%

str(first.query)

SELECT "paying_for_college_notification"."id", "paying_for_college_notification"."url", 
"paying_for_college_notification"."institution_id", "paying_for_college_notification"."oid", 
"paying_for_college_notification"."timestamp", "paying_for_college_notification"."errors", 
"paying_for_college_notification"."emails", "paying_for_college_notification"."sent", 
"paying_for_college_notification"."log" 
FROM "paying_for_college_notification" 
WHERE "paying_for_college_notification"."oid"::text LIKE %1% 
ORDER BY "paying_for_college_notification"."timestamp" ASC

str(last.query)

SELECT "paying_for_college_notification"."id", "paying_for_college_notification"."url", 
"paying_for_college_notification"."institution_id", "paying_for_college_notification"."oid", 
"paying_for_college_notification"."timestamp", "paying_for_college_notification"."errors", 
"paying_for_college_notification"."emails", "paying_for_college_notification"."sent", 
"paying_for_college_notification"."log" 
FROM "paying_for_college_notification" 
WHERE "paying_for_college_notification"."oid"::text LIKE %1% 
ORDER BY "paying_for_college_notification"."timestamp" ASC