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fix: only one query for 1o1 relation

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This commit is contained in:
Laurent Riviere 2023-05-22 16:28:30 +00:00
parent edb9690dbc
commit 013dbbefc6
1 changed files with 10 additions and 27 deletions
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37
graphene_django/converter.py
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@ -299,33 +299,16 @@ def convert_onetoone_field_to_djangomodel(field, registry=None):
# the default Django resolver
return fk_obj
object_pk = resolver(root, info, **args).pk
instance_from_get_node = _type.get_node(info, object_pk)
if instance_from_get_node is None:
# no instance to return
return
elif (
isinstance(resolver, partial)
and resolver.func is get_default_resolver()
):
return instance_from_get_node
elif resolver is not get_default_resolver():
# Default resolver is overridden
# For optimization, add the instance to the resolver
field_name = to_snake_case(info.field_name)
setattr(root, field_name, instance_from_get_node)
# Explanation:
# previously, _type.get_node` is called which results in at least one hit to the database.
# But, if we did not pass the instance to the root, calling the resolver will result in
# another call to get the instance which results in at least two database queries in total
# to resolve this node only.
# That's why the value of the object is set in the root so when the object is accessed
# in the resolver (root.field_name) it does not access the database unless queried explicitly.
fk_obj = resolver(root, info, **args)
return fk_obj
else:
return instance_from_get_node
field_name = to_snake_case(info.field_name)
reversed_field_name = root.__class__._meta.get_field(
field_name
).remote_field.name
return _type.get_queryset(
_type._meta.model.objects.filter(
**{reversed_field_name: root.pk}
),
info,
).get()
return custom_resolver