Select Star Over Fetch (ARCH2066)

Key python.orm.select-star-over-fetch · Severity info · Category orm

Fetching whole entities or all columns when only a few fields are used downstream needlessly inflates row width and serialization cost. Use a projection.

Incorrect

def emails():
    return [u.email for u in User.objects.all()]  # all columns fetched

Correct

def emails():
    return list(User.objects.values_list("email", flat=True))  # email only

Fix

Fetch only the needed fields with a values() / values_list() projection.