#35294: Queryset explain truncated
-------------------------------------+-------------------------------------
               Reporter:  Gordon     |          Owner:  nobody
  Wrigley                            |
                   Type:             |         Status:  new
  Uncategorized                      |
              Component:  Database   |        Version:  4.2
  layer (models, ORM)                |
               Severity:  Normal     |       Keywords:  explain
           Triage Stage:             |      Has patch:  0
  Unreviewed                         |
    Needs documentation:  0          |    Needs tests:  0
Patch needs improvement:  0          |  Easy pickings:  0
                  UI/UX:  0          |
-------------------------------------+-------------------------------------
 Django 4.2.10
 Python 3.10.13
 Postgres 15.6
 Psycopg2 2.9.9

 I have some very complex querysets I'm trying to optimize and what I've
 run into is explain output is being truncated at 100 lines. As far as I
 can tell this is because of this function on
 django.db.models.sql.compiler.SQLCompiler.

 {{{#!python
     def explain_query(self):
         result = list(self.execute_sql())
         # Some backends return 1 item tuples with strings, and others
 return
         # tuples with integers and strings. Flatten them out into strings.
         format_ = self.query.explain_info.format
         output_formatter = json.dumps if format_ and format_.lower() ==
 "json" else str
         for row in result[0]:
             if not isinstance(row, str):
                 yield " ".join(output_formatter(c) for c in row)
             else:
                 yield row
 }}}

 Where `result[0]` is ignoring additional results. Monkey patching it to

 {{{#!python
     def explain_query(self):
         results = list(self.execute_sql())
         # Some backends return 1 item tuples with strings, and others
 return
         # tuples with integers and strings. Flatten them out into strings.
         format_ = self.query.explain_info.format
         output_formatter = json.dumps if format_ and format_.lower() ==
 "json" else str
         for result in results:
             for row in result:
                 if not isinstance(row, str):
                     yield " ".join(output_formatter(c) for c in row)
                 else:
                     yield row
 }}}

 Gets me the full explain output.
-- 
Ticket URL: <https://code.djangoproject.com/ticket/35294>
Django <https://code.djangoproject.com/>
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