UUID or Auto Increment Integer: Best Primary Key for your DB

Introduction

If you've found yourself asking the same age-old question: “Should I use UUIDs or auto-incrementing integers for my primary keys?”—congratulations! You're officially one of us, a developer with existential dilemmas. It’s like choosing between pizza or tacos… both great, but which one will leave your system happier in the long run?

Let’s dive in and explore these two contenders in the arena for the crown of "Best Primary Key."

Round 1: Auto Increment Integer - The Classic Choice

First up in the ring, we have the auto-increment integer, or a few people might call it, the "Old Reliable." It's simple, predictable, and grows slowly with time. It has been around since databases were filled with nothing but cat names and high scores from Snake.

Pros:

1. Simple and straightforward:
   The next ID is just the last ID +1. No rocket science or complex calculations are involved here.

2. Small size:
   Auto-increment integers are lightweight—like that person who only orders a side salad while you're getting the triple-cheese burger. Minimal space usage, maximum efficiency.

3. Readable and predictable:
   When you see a 1, then a 2, and then a 3, your brain is happy. It's a tidy, linear progressive.

Cons:

1. Scalability issues:
   Auto-increment values are great until your app blows up like the latest TikTok trend. Then you might start to worry about concurrency issues, race conditions, and "what if I run out of numbers?" Yeah, it's a thing.

2. Sharding headaches:
   Imagine splitting your data across multiple servers. Suddenly, each server is dishing out its own set of IDs like confused waiters in a busy restaurant. Now your ID isn’t unique anymore—chaos ensues.

3. Predictability is a double-edged sword:
   Sure, predictable is nice… until someone guesses your next value, and your security team gives you the look. It’s like leaving your house key under the doormat—just don’t.

4. Can’t be used in Distributed Systems:

   It can't be used in the distributed system since it's quite likely that different hosts could produce exactly the same number.

Database Support -

Every major database engine provides the native support including the following :-

• MySQL - AUTO_INCREMENT

• PostgreSQL - SERIAL

• SQL Server - IDENTITY

• SQLite - AUTOINCREMENT

Round 2: UUID - The New Kid on the Block

Now, let’s talk about UUIDs (Universally Unique Identifiers), A.KA. "That big gibberish string." UUIDs are for when you need something a little more exotic, like a designer coffee order. They're massive, unique, and downright mysterious.

The original UUID standard includes 5 UUID formats. Most of the time, people either choose UUIDv1 (timestamp) or UUIDv4 (random).

Pros:

1. Globally unique:
   A UUID is so unique, it's like a snowflake at a snowflake convention. The chances of creating two identical ones are astronomically small. (We’re talking "winning the lottery while being struck by lightning" kind of small.)

2. Great for distributed systems:
   If you’ve got databases in different regions or on different servers, UUIDs let you rest easy. They don't need to talk to each other to generate unique keys.

3. Security through obscurity:
   Unlike auto-increment integers, nobody is going to guess your next UUID unless they’ve got a supercomputer and a lot of spare time. It’s like locking your database inside a safe… that’s inside another safe.

4. Stateless:

   Since, UUID is stateless, it can be generated on the fly.

Cons:

1. Bigger is not always better:
   At 128 bits, UUIDs are huge. Storing them can take up a chunk of space, and when it comes to indexing, they’re not exactly snappy. It's like trying to squeeze a football team into a tiny elevator—possible, but not recommended.

2. Not human-friendly:
   Ever tried reading a UUID? Yeah, me neither. They're long and filled with enough random characters to make your eyes cross. Debugging with UUIDs is about as much fun as solving a Rubik’s cube blindfolded.

3. Randomness can be messy:
   Unlike those neat, tidy integers, UUIDs have a habit of being, well, all over the place. Query performance can take a hit because UUIDs aren’t stored in a predictable order—kind of like trying to find your car keys after a wild night out.

4. Not sortable:

   UUIDs are naturally non-sortable according to creation time. Though v1 UUID format contains timestamp, it encodes the timestamp using little-endian in that the least significant time appears first, which renders the UUID hard to sort according to creation time.

Round 3: The Wildcard Contender - UUID v7

Although, a lot of solutions are invented to address the limitation of UUID. IETF also published a draft in April 2021 to propose a new UUID format. And in May 2024, IETF finally approved the draft. The approved UUIDv7 format:

## uuid7 layout
 0                   1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                           unix_ts_ms                          |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|          unix_ts_ms           |  ver  |       rand_a          |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|var|                        rand_b                             |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                            rand_b                             |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

UUID v7 is one of the newer variants in the UUID family that combines the best aspects of auto-incrementing integers and the global uniqueness of traditional UUIDs.

UUID v7 is a time-ordered UUID, which means its primary focus is combining temporal ordering with random uniqueness. Unlike older versions like UUID v4 (which are fully random) or v1 (which is based on the system's MAC address and timestamp), v7 primarily uses a timestamp component to ensure it can be ordered sequentially and still retains enough randomness to be globally unique.

Some other benefits of using UUID v7

• Efficiency of Sequential Storage:
  UUID v7’s timestamp-based component means new UUIDs are naturally ordered over time, which helps with performance in databases. Sequential ordering improves cache locality and index efficiency, reducing fragmentation in storage.

• Avoids the Concurrency Issues of Auto-Increment Integers:
  One of the biggest problems with auto-increment integers is concurrency. When many systems or nodes try to generate keys at the same time, race conditions can occur, causing issues with duplicate keys or key contention. UUID v7 bypasses this problem entirely because it’s generated independently on each system and remains unique.

• Readable in Time-Series Data:
  While traditional UUIDs are purely random, UUID v7 is partially timestamp-based, so you can look at a UUID and get a rough idea of when it was generated. This makes it easier to work with time-series data or perform audits.

K.O. : Which One Should You Choose?

So, now that the contenders have shown their strengths and weaknesses, how do you choose?

• If you're building a small-to-medium-sized app with one database and you like things predictable, auto-increment integers are your friend. It’s like driving a dependable old sedan—nothing fancy, but it gets the job done.

• If you're designing a globally distributed system, handling large amounts of data, or running multiple databases that need to generate unique keys without colliding, UUIDs are the shiny new sports car in your garage. Sure, it's a bit extra, but sometimes you want that extra.

Final Thoughts

When it comes to picking the right primary key for your database, there’s no one-size-fits-all. Auto-increment integers are great for small-scale applications where you don’t need to worry about sharding or global uniqueness. UUIDs, on the other hand, are perfect when you need something scalable and distributed but don’t mind sacrificing a little storage and readability.

At the end of the day, the best choice is the one that works for your specific use case. Just like deciding between pizza or tacos—both is always an option.

Happy coding! May your primary keys always be unique.