A developer reports experiencing an actual UUID v4 collision in their production database, which is considered statistically near-impossible. The incident occurred with a relatively small dataset of 15,000 records, raising concerns about the reliability of UUID v4 implementations and entropy sources. The Hacker News discussion reveals that such collisions are more common than expected due to issues with entropy sources and implementation details.
Background
UUID v4 is a widely used standard for generating unique identifiers, with a theoretical collision probability of nearly zero (1 in 2^122). It relies on high-quality random number generation to ensure uniqueness across distributed systems.
- Source
- hackernews
- Published
- May 8, 2026 at 03:57 PM
- Score
- 8.0 / 10