From c62c09f603dc0c0cb09031739c07ee414e02a06d Mon Sep 17 00:00:00 2001
From: imperosol <thgirod@hotmail.com>
Date: Thu, 12 Jun 2025 14:35:39 +0200
Subject: [PATCH] fix: counter selection queryset performance on SellingForm
---
club/forms.py | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/club/forms.py b/club/forms.py
index 6bb09fc4..5d6a3b10 100644
--- a/club/forms.py
+++ b/club/forms.py
@@ -163,15 +163,16 @@ class SellingsForm(forms.Form):
def __init__(self, club, *args, **kwargs):
super().__init__(*args, **kwargs)
- counters_qs = (
- Counter.objects.filter(
- Q(club=club)
- | Q(products__club=club)
- | Exists(Selling.objects.filter(counter=OuterRef("pk"), club=club))
- )
- .distinct()
- .order_by(Lower("name"))
+ # postgres struggles really hard with a single query having three WHERE conditions,
+ # but deals perfectly fine with UNION of multiple queryset with their own WHERE clause,
+ # so we do this to get the ids, which we use to build another queryset that can be used by django.
+ club_sales_subquery = Selling.objects.filter(counter=OuterRef("pk"), club=club)
+ ids = (
+ Counter.objects.filter(Q(club=club) | Q(products__club=club))
+ .union(Counter.objects.filter(Exists(club_sales_subquery)))
+ .values_list("id", flat=True)
)
+ counters_qs = Counter.objects.filter(id__in=ids).order_by(Lower("name"))
self.fields["counters"] = forms.ModelMultipleChoiceField(
counters_qs, label=_("Counter"), required=False
)