database-optimization.md

technology	PostgreSQL
domain	backend
level	Senior/Architect
version	16+
tags	best-practices deterministic-code architecture-patterns vibe-coding postgresql database sql rdbms system-design production-ready scalable-code
ai_role	Senior PostgreSQL Database Architect
last_updated	2026-03-27

🐘 PostgreSQL Database Optimization

⬅️ Back to Parent

1. 🛑 Missing Indexes on Foreign Keys

❌ Bad Practice

CREATE TABLE orders (
    id SERIAL PRIMARY KEY,
    user_id INT REFERENCES users(id),
    total DECIMAL
);
-- No index on user_id

⚠️ Problem

Failing to index foreign keys results in full table scans during joins and cascading deletes, leading to exponential performance degradation as data grows.

✅ Best Practice

CREATE TABLE orders (
    id SERIAL PRIMARY KEY,
    user_id INT REFERENCES users(id),
    total DECIMAL
);
CREATE INDEX idx_orders_user_id ON orders(user_id);

Note

Internal Routing: For more context, refer back to the Postgresql Index.

🚀 Solution

Always create explicit indexes on foreign key columns and frequently queried fields to ensure deterministic query execution times (O(log n) vs O(n)).

2. 🗂️ Architectural Workflow

graph TD
    A[Query Planner] --> B[Index Scan]
    B --> C[(Table Data)]

    classDef default fill:#e1f5fe,stroke:#03a9f4,stroke-width:2px,color:#000;
    classDef component fill:#e8f5e9,stroke:#4caf50,stroke-width:2px,color:#000;
    classDef layout fill:#f3e5f5,stroke:#9c27b0,stroke-width:2px,color:#000;

    class A layout;
    class B component;
    class C component;

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