#34450: Lookup expressions across foreign keys introduce extra joins
-------------------------------------+-------------------------------------
Reporter: Roman Odaisky | Owner: nobody
Type: Bug | Status: new
Component: Database layer | Version: 4.1
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Comment (by Simon Charette):
Haven't run the full test suite yet but it seems that intuitively passing
`reuse` so the JOINs are reused does the trick for this particular issue
at least
{{{#!python
diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py
index 3cb8bdbc8a..1ed7d7cb6e 100644
--- a/django/db/models/sql/query.py
+++ b/django/db/models/sql/query.py
@@ -1373,7 +1373,7 @@ def build_filter(
if not getattr(filter_expr, "conditional", False):
raise TypeError("Cannot filter against a non-conditional
expression.")
condition = filter_expr.resolve_expression(
- self, allow_joins=allow_joins, summarize=summarize
+ self, allow_joins=allow_joins, reuse=can_reuse,
summarize=summarize,
)
if not isinstance(condition, Lookup):
condition = self.build_lookup(["exact"], condition, True)
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/34450#comment:4>
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