[Django] #34811: Queryset filter Q order changed

[Django]

#34811: Queryset filter Q order changed
-------------------------------------+-------------------------------------
               Reporter:             |          Owner:  nobody
  cosmoscalibur                      |
                   Type:  Bug        |         Status:  new
              Component:  Database   |        Version:  4.2
  layer (models, ORM)                |
               Severity:  Normal     |       Keywords:  filter, Q
           Triage Stage:             |      Has patch:  0
  Unreviewed                         |
    Needs documentation:  0          |    Needs tests:  0
Patch needs improvement:  0          |  Easy pickings:  0
                  UI/UX:  0          |
-------------------------------------+-------------------------------------
 Using filters in order explicitly expressed by user is important because
 take advantage of indexes.

 When apply this query


 {{{
 TaxInput.objects.all(
                 force_visibility=True
             ).filter(
                 Q(filling_id=pk, updated_at__gt=last_engine.created_at)
                 | Q(filling_id=pk, deleted__gt=last_engine.created_at),
             )
 }}}


 the MySQL generated query is


 {{{
 SELECT
   *
 FROM
   `taxobjects_taxinput`
 WHERE
   ( `taxobjects_taxinput` . `filling_id` = ?
     AND `taxobjects_taxinput` . `updated_at` > ? )
   OR ( `taxobjects_taxinput` . `deleted` > ?
     AND `taxobjects_taxinput` . `filling_id` = ? )
 LIMIT
   ?
 }}}


 But should be


 {{{
 SELECT
   *
 FROM
   `taxobjects_taxinput`
 WHERE
   ( `taxobjects_taxinput` . `filling_id` = ?
     AND `taxobjects_taxinput` . `updated_at` > ? )
   OR ( `taxobjects_taxinput` . `filling_id` > ?
     AND `taxobjects_taxinput` . `deleted` = ? )
 LIMIT
   ?
 }}}

 This change of order create a 10x factor in query time, because this table
 has index filing_id, and also index (filing_id, deleted).

 Using Django 4.2.1 and SafeDelete 1.3.1 (because this is used
 force_visibility=True in all manager).

-- 
Ticket URL: <https://code.djangoproject.com/ticket/34811>
Django <https://code.djangoproject.com/>
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