#34639: MySQL 8.0 hangs indefinitely when using the admin search with a Foreign 
Key
and Annotate
-------------------------------------+-------------------------------------
     Reporter:  Nicolas Lupien       |                    Owner:  Simon
                                     |  Charette
         Type:  Bug                  |                   Status:  assigned
    Component:  contrib.admin        |                  Version:  4.2
     Severity:  Normal               |               Resolution:
     Keywords:  mysql                |             Triage Stage:  Ready for
                                     |  checkin
    Has patch:  1                    |      Needs documentation:  0
  Needs tests:  0                    |  Patch needs improvement:  0
Easy pickings:  0                    |                    UI/UX:  0
-------------------------------------+-------------------------------------

Comment (by Mariusz Felisiak <felisiak.mariusz@…>):

 In [changeset:"28e2077148f7602d29165e90965974698819cbba" 28e20771]:
 {{{
 #!CommitTicketReference repository=""
 revision="28e2077148f7602d29165e90965974698819cbba"
 Refs #32433 -- Reallowed calling QuerySet.delete() after distinct().

 While values(*field_excluding_pk).distinct() and
 distinct(*field_excluding_pk) can reduce the number of resulting rows
 in a way that makes subsequent delete() calls ambiguous standalone
 .distinct() calls cannot.

 Since delete() already disallows chain usages with values() the only
 case that needs to be handled, as originally reported, is when
 DISTINCT ON is used via distinct(*fields).

 Refs #32682 which had to resort to subqueries to prevent duplicates in
 the admin and caused significant performance regressions on MySQL
 (refs #34639).

 This partly reverts 6307c3f1a123f5975c73b231e8ac4f115fd72c0d.
 }}}

-- 
Ticket URL: <https://code.djangoproject.com/ticket/34639#comment:14>
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