Overview
- Bug Type:
- Uniqueness constraint violation
- Category:
- State & Data Consistency
Definition
A value expected to be unique appears more than once due to missing or weak enforcement.
How to fix Uniqueness constraint violation?
Add UNIQUE constraints/indexes; use atomic upserts; introduce idempotency keys; handle conflicts explicitly
Symptoms
Observable signs that may indicate Uniqueness constraint violation:
- Duplicate keys or usernames appear after concurrent inserts.
- Database raises unique/duplicate key errors.
- Idempotent operations still create duplicates.
Example Errors:
- ERROR: duplicate key value violates unique constraint
- E11000 duplicate key error collection
- Unique index violation on (field)