Normalization Performance:

Write Performance (Improved):

- Unnormalized: Update customer email in 100 order rows (100 writes)

- Normalized: Update customer email in 1 customer row (1 write)

- Normalization improves write performance (fewer rows to update)

Read Performance (Degraded):

- Unnormalized: SELECT * FROM orders (1 table scan)

- Normalized: SELECT * FROM orders JOIN customers JOIN order_items JOIN products (4 table scans + 3 joins)

- Normalization degrades read performance (more joins)

Storage (Improved):

- Unnormalized: Customer name stored in every order row (100 orders = 100 copies)

- Normalized: Customer name stored once in customers table (100 orders = 1 copy)

- Normalization saves storage (no redundancy)

Consistency (Improved):

- Unnormalized: Update customer email, might miss some order rows (inconsistent)

- Normalized: Update customer email once, all orders see new email (consistent)

- Normalization improves consistency (single source of truth)

Query Complexity (Increased):

- Unnormalized: Simple queries (SELECT * FROM orders)

- Normalized: Complex queries (JOIN multiple tables)

- Normalization increases query complexity

Indexing:

- Normalized tables: Index foreign keys for fast joins

- Example: CREATE INDEX idx_orders_customer_id ON orders(customer_id);

- Without index: JOIN scans entire table (slow)

- With index: JOIN uses index seek (fast)

Real-world Performance:

- Stripe: Normalized to 3NF, indexes all foreign keys, 30K+ transactions/sec

- Amazon: Normalized to 3NF for orders, denormalized for product catalog (read-heavy)

- Netflix: Normalized to 3NF for user data, denormalized for recommendations (read-heavy)

Optimization Strategies:

1. Normalize to 3NF by default

2. Identify slow queries (> 100ms)

3. Selectively denormalize hot paths

4. Use materialized views for expensive joins

5. Cache frequently accessed data

6. Monitor query performance continuously

Index foreign keys for fast joins: CREATE INDEX idx_orders_customer_id ON orders(customer_id)

Use EXPLAIN to analyze joins: Identify slow joins, add indexes or denormalize

Materialize expensive joins: CREATE MATERIALIZED VIEW for frequently joined tables