UUID

A UUID is another easy way to obtain unique IDs. UUID is a 128-bit number used to identify information in computer systems. UUID has a very low probability of getting collusion. Quoted from Wikipedia, “after generating 1 billion UUIDs every second for approximately 100 years would the probability of creating a single duplicate reach 50%”.

Here is an example of UUID: 09c93e62-50b4-468d-bf8a-c07e1040bfb2. UUIDs can be generated independently without coordination between servers. The picture below presents the UUID's design.

In this design, each web server contains an ID generator, and a web server is responsible for generating IDs independently.

Pros:

• Generating UUID is simple. No coordination between servers is needed so there will not be any synchronization issues.

• The system is easy to scale because each web server is responsible for generating IDs they consume. ID generators can easily scale with web servers.

Cons:

• IDs are 128 bits long, but our requirement is 64 bits.

• IDs do not go up with time.

• IDs could be non-numeric.