In the world of database design,
particularly when using PostgreSQL,
a common question arises regarding the choice of
data type for identity columns:
should one use UUIDs or big integers (bigint)?
Both options have their unique advantages and
drawbacks, and the decision ultimately depends on the
specific requirements of your application.
Let's explore the pros and cons of each to help you make
an informed decision.
What are UUIDs?
UUID stands for Universal Unique Identifier. As the name suggests, UUIDs are designed to be globally unique across tables, databases, and even servers. A UUID is a 128-bit value, typically represented as a 36-character string (including hyphens). This uniqueness comes at the cost of size and complexity in generation and handling.
Pros of Using UUIDs
- Global Uniqueness: The primary advantage of UUIDs is their guarantee of uniqueness beyond the scope of a single database. This is particularly useful for distributed systems where data from multiple sources might need to be merged or synchronized without conflicts.
- Anonymity: UUIDs do not reveal information about when or where they were generated, which can be beneficial for privacy and security considerations.
- Scalability: Since UUIDs do not need a central authority to ensure their uniqueness, they are well-suited for scaling out, especially in distributed databases and microservices architectures.
Cons of Using UUIDs
- Performance: The size of UUIDs (16 bytes) is larger than that of a bigint (8 bytes), which can lead to increased storage requirements and potentially slower performance in index lookups and joins.
- Readability: UUIDs are not human-readable, making manual inspection and debugging more challenging.
- Complexity: Generating UUIDs requires more computational effort than incrementing a numerical value, and their non-sequential nature can lead to fragmented indexes over time.
What is bigint?
A bigint is a large-range integer data type that
occupies 8 bytes of storage.
It can store numbers from -9223372036854775808 to
9223372036854775807, providing a vast range that is
sufficient for many applications.
Pros of Using bigint
- Performance: bigint values are smaller and more straightforward to generate than UUIDs, leading to better performance in terms of storage, indexing, and join operations.
- Simplicity: Using numeric IDs is straightforward and familiar to most developers, making implementation and maintenance easier.
- Sequentiality: bigint IDs are usually generated sequentially, which ensures a well-ordered index and can improve data retrieval speed.
Cons of Using bigint
- Scalability Limitations: In distributed systems, generating unique bigint IDs can require coordination between nodes to avoid conflicts, which can complicate the architecture and limit scalability.
- Predictability: Sequential IDs can inadvertently expose information about the number of records in a database or the rate at which records are created, potentially posing a security risk.
Conclusion
The choice between UUIDs and bigint as identity columns in PostgreSQL
hinges on the specific needs of your application.
If you require global uniqueness, are building a distributed system,
or need to avoid revealing information through your IDs, UUIDs are the
way to go.
On the other hand, if your priorities are performance, simplicity,
and sequential order, bigint is likely a better choice. Remember, the decision isn't always binary. Some applications might
benefit from using both types of identifiers in different parts of
the system. It's crucial to weigh the pros and cons in the context
of your project's requirements to make the best decision.