How can a mechanism for generating unique identifiers for requests be implemented in a scalable system?

In scalable systems, the following approaches are often used to generate unique request identifiers:

1. UUID (Universally Unique Identifier) — a standard method that generates 128-bit unique identifiers. In Java, you can use java.util.UUID.randomUUID(). The drawback is that the identifiers are quite long.

2. Snowflake ID — an algorithm from Twitter that generates 64-bit unique numbers based on time, machine ID, and sequence. It allows creating ordered and unique IDs in a distributed system.

3. Combination of time and a unique prefix — for example, timestamp + server ID + counter.

4. Use of specialized services — such as databases with auto-increment or distributed ID generators (Zookeeper, Redis).

Example of UUID generation in Java:

import java.util.UUID;

public class UniqueIdGenerator {
    public static String generateRequestId() {
        return UUID.randomUUID().toString();
    }
}

For high-load systems, it is recommended to use Snowflake or similar algorithms to avoid collisions and ensure scalability.