Is the Claim of GUID Uniqueness Valid?

Brief proof that GUIDs are not absolutely unique

Introduction

GUIDs are often considered unique, but does this hold up to scrutiny? This article will delve into the details of GUID generation and provide a code example that challenges its alleged uniqueness.

Methodological considerations

The relevant code iterates from 0 to 2¹²⁸-1 and generates a GUID for each iteration. Although the program was expected to run for a long time, it exited unusually early.

Solution

To correct this problem, the code must run concurrently using multiple threads. This is an improved version:

<code>for (long k = 0; k 
        {
            // 使用bigHeapOGuids检查冲突
        }
    }
}</code>

This approach uses parallel processing to continuously check for conflicts between newly generated GUIDs and GUIDs already stored in the bigHeapOGuids hash set.

Discuss

By running this program indefinitely, it is obvious that the GUID is not unique. This code disproves the uniqueness argument by iterating over a huge range of values, inevitably generating duplicates.

Disclaimer

Use of this program is subject to unique license terms: $0.0001 per hour per CPU core used. Payment is due at the end of each calendar month. Please contact the author for PayPal account information.

Conclusion

This modified code proves that GUIDs are not inherently unique, despite common misconception. By using multiple threads, a program can effectively test for conflicts and prove the fallacy of so-called uniqueness guarantees.

The above is the detailed content of Is the Claim of GUID Uniqueness Valid?. For more information, please follow other related articles on the PHP Chinese website!