Common Mistakes & Misconceptions

Determinism

• “Exact means fast.” It can be slower than ANN at scale.
• “Replay is optional.” If you care about audits, it is required.

ND

• “ND is just faster exact.” It is approximate and bounded.
• “Seeds make ND deterministic.” Seeds help; they don’t replace bounds.

Vector stores

• “Deletes are permanent.” Not unless the backend guarantees it.
• “All backends are equivalent.” Capabilities differ.