Missing Index Candidate (ARCH2058)

Key python.orm.missing-index-candidate · Severity info · Category orm

Columns used repeatedly in filter, order, or lookup predicates but lacking an index cause full scans. A DB index is heuristically suggested.

Incorrect

class Order(models.Model):
    email = models.CharField(max_length=255)  # filtered often but unindexed

Order.objects.filter(email=value)

Correct

class Order(models.Model):
    email = models.CharField(max_length=255, db_index=True)

Order.objects.filter(email=value)

Fix

Add db_index=True or a composite Index declaration to frequently filtered columns.