#28933: Implement a range-based filter for Django Admin date_hierarchy
-----------------------------------------+--------------------------------
               Reporter:  hakib          |          Owner:  nobody
                   Type:  New feature    |         Status:  new
              Component:  contrib.admin  |        Version:  2.0
               Severity:  Normal         |       Keywords:  date_hierarchy
           Triage Stage:  Unreviewed     |      Has patch:  0
    Needs documentation:  0              |    Needs tests:  0
Patch needs improvement:  0              |  Easy pickings:  0
                  UI/UX:  0              |
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 The predicate generated by date_hierarchy makes it very difficult for
 databases to optimize the query.

 The following date hierarchy:

 {{{
 /admin/app/model?created__year=2017&created__month=12&created__day=16
 }}}

 Will generate the following where clause (PostgreSql):

 {{{
 WHERE created between '2017-01-01' and '2017-31-12' and EXTRACT('month',
 created) = 12 and EXTRACT('day', created) = 16
 }}}


 The query above will not be able to utilize range based indexes on the
 date hierarchy column - on big tables this has a significant performance
 impact.

 The current implementation of date hierarchy is relying on the "default"
 filtering mechinizem used by Django Admin. **I propose implementing custom
 filtering for Django Admin that will better utilize it's hierarchical
 nature and make it more database "friendly".**

 Instead of the query above the date hierarchy would generate the following
 predicates for different levels of the heirarchy:


 {{{
 /admin/app/model?created__year=2017&created__month=12&created__day=16
 WHERE created >= '2017-12-16' and created < '2017-12-17'
 }}}


 {{{
 /admin/app/model?created__year=2017&created__month=12
 WHERE created >= '2017-12-01' and created < '2018-01-01'
 }}}


 {{{
 /admin/app/model?created__year=2017
 WHERE created >= '2017-01-01' and created < '2018-01-01'
 }}}


 I already [wrote about this issue](https://codeburst.io/django-admin-
 range-based-date-hierarchy-37955b12ea4e) and [published a
 package](https://github.com/hakib/django-admin-lightweight-date-
 hierarchy/blob/master/django_admin_lightweight_date_hierarchy/admin.py)
 that implement the above as a custom SimpleListFilter.

 I already have a PR ready - I'm following proper protocol here so please
 let me know if this is acceptable.

-- 
Ticket URL: <https://code.djangoproject.com/ticket/28933>
Django <https://code.djangoproject.com/>
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