ChatGPT answer - DB UUID vs Auto Increment Performance

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ChatGPT answer - DB UUID vs Auto Increment Performance


2 min read

My question is "uuid vs auto increment performance, give your answer in a markdown code block".

Here is ChatGPT's answer:

UUID vs Auto Increment Performance

When choosing between UUID and auto-increment for primary keys in a database, several performance and practical considerations come into play. Here is a comparison of their performance characteristics:

UUID (Universally Unique Identifier)


  • Uniqueness: Guarantees global uniqueness across tables, databases, and even servers, making it ideal for distributed systems.
  • Scalability: Avoids potential bottlenecks in distributed environments because UUIDs can be generated independently.
  • Security: Harder to guess the next ID, adding a layer of security.


  • Size: UUIDs are larger (typically 128 bits) compared to integers (usually 32 or 64 bits), which can increase storage requirements.
  • Index Performance: Due to their size and randomness, UUIDs can lead to fragmented indexes and slower performance for indexed queries.
  • Readability: UUIDs are less human-readable compared to auto-increment integers.

Performance Impact:

  • Insert Operations: Slightly slower because the randomness of UUIDs can cause more page splits in the index.
  • Query Performance: Slower indexed lookups due to larger and more fragmented indexes.
  • Storage: Higher storage requirements due to the larger size of UUIDs.

Auto Increment


  • Simplicity: Simple and straightforward to implement.
  • Performance: Generally faster for insert operations and indexed lookups due to smaller and sequential nature.
  • Storage: Requires less storage space compared to UUIDs.


  • Scalability: Can be a bottleneck in distributed systems because of the need to synchronize the incrementing sequence.
  • Predictability: Easier to guess the next ID, which might be a security concern in some cases.
  • Limit: Fixed range based on the integer size (e.g., 32-bit or 64-bit).

Performance Impact:

  • Insert Operations: Faster due to sequential nature, leading to fewer page splits in the index.
  • Query Performance: More efficient indexed lookups due to smaller and more compact indexes.
  • Storage: Lower storage requirements compared to UUIDs.


  • Use UUIDs if you need global uniqueness, are working in a distributed system, or require additional security for primary keys.
  • Use Auto Increment if you prioritize performance and storage efficiency, particularly in a non-distributed, single-database environment.

Choosing between UUID and auto increment largely depends on the specific requirements and constraints of your application. Consider the trade-offs in terms of performance, storage, scalability, and security when making your decision.

End of ChatGPT's answer. It looks good to me!