UUIDs are everywhere in modern applications — for users, orders, events, and more. But if you're storing them in PostgreSQL, are you getting the best performance and clarity?

Let's dive into how PostgreSQL supports UUIDs natively, and how to use them efficiently with the right generation, indexing, and storage strategies.

🧬 The Native UUID Type

PostgreSQL has a built-in uuid type that stores UUIDs as 16 bytes — compact, binary, and efficient.

✅ Benefits:

Smaller than a CHAR(36) UUID string
Faster comparisons and joins
Uses native binary format, not text

🔧 Example Table

sql

CREATE TABLE users (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  name TEXT
);

This gives you:

Compact primary key
No user-managed ID generation
Easy joins and lookups using native uuid type

🔑 Generating UUIDs: `gen_random_uuid()` vs `uuid_generate_v4()`

PostgreSQL offers two main options:

1. `gen_random_uuid()` from `pgcrypto`

sql

CREATE EXTENSION IF NOT EXISTS "pgcrypto";

SELECT gen_random_uuid();

Uses cryptographically secure randomness
UUIDv4 format
Recommended for production use

2. `uuid_generate_v4()` from `uuid-ossp`

sql

CREATE EXTENSION IF NOT EXISTS "uuid-ossp";

SELECT uuid_generate_v4();

Also generates UUIDv4
Slightly more overhead
More flexible (supports v1, v3, v5 too)

✅ Recommendation

Use pgcrypto's gen_random_uuid() unless you need other UUID versions.

📈 Indexing Performance

🔍 Index on UUID

sql

CREATE INDEX idx_users_id ON users (id);

Native UUIDs index well — but random UUIDs (v4) cause scattered inserts in B-tree indexes.

🧠 Improve Locality with Time-Based UUIDs

Use UUIDv7 or ULID for sortable identifiers
Improves index locality and cache efficiency

If using UUIDv4, consider:

Random insert patterns = slower index performance
CLUSTERing periodically if you need better scan locality

🧪 Sorting and Querying

Common patterns:

sql

-- Latest user
SELECT * FROM users ORDER BY created_at DESC LIMIT 1;

-- Find by UUID
SELECT * FROM users WHERE id = '550e8400-e29b-41d4-a716-446655440000';

UUIDs sort lexicographically, not chronologically — unless you use time-based UUIDs.

📊 Storage Efficiency

Format	Size	Notes
`uuid`	16B	Native, fast, compact
`CHAR(36)`	36B	Avoid — wastes space
`BYTEA`	16B+	Works, but less ergonomic

Stick to the uuid type unless you have exotic encoding needs.

🧰 Tips for Working with UUIDs in PostgreSQL

Tip	Why it helps
Use `uuid` not `char/varchar`	Saves space, faster operations
Default to `gen_random_uuid()`	Built-in, safe, no external deps required
Index your UUIDs	Fast lookup and joins
Avoid truncating UUIDs	Breaks uniqueness
Use UUIDv7/ULID for sortability	Better B-tree performance on large tables

⚠️ Anti-Patterns to Avoid

Text UUID columns: wastes space, slower comparisons
Sequential UUIDs with `uuid_generate_v1()`: can leak MAC/timestamp
Custom UUID strings: not compatible with tooling or type system
Unindexed UUID joins: can cripple performance

Final Thoughts

PostgreSQL makes UUIDs first-class citizens — fast, efficient, and schema-friendly.

But the secret to success is not just “use UUIDs” — it’s use them right:

Compact storage ✅
Smart generation ✅
Strategic indexing ✅

🐘 UUIDs + PostgreSQL = powerful combo. Now go use it for fun and profit.

PostgreSQL and UUIDs: Leveraging Native UUID Types for Fun and Profit