Should I Use UUIDs as Primary Keys in MySQL for High-Volume Inserts?

UUID Performance in MySQL: Considerations and Recommendations

MySQL users considering UUIDs as primary keys for inserts ranging from 100-40,000 per second may have performance concerns.

Storage Formats:

While storing UUIDs as VARCHAR(36) is initially considered, BINARY(16) is more efficient, significantly reducing storage space.

Random Data Impact on Index:

Randomly distributed UUIDs can adversely affect index performance, especially with large datasets (50M records or more). The lack of sequential order results in fragmented pages and degraded select performance.

UUID Types and Timestamped Values:

Type-1 UUIDs with timestamped leftmost bits may offer improved performance due to their inherent order, reducing page fragmentation. However, this requires careful implementation to ensure accurate timestamping.

Auto-Increment Primary Keys as an Alternative:

Auto-increment primary keys offer sequential ordering, maximizing insert performance and reducing fragmentation. Additionally, auto-increments are inherently smaller, reducing storage overhead.

Recommendation:

Based on the mentioned requirements and potential performance challenges, the recommended approach is not to use UUIDs as primary keys. Instead, consider the following hybrid model:

1. Use an INT Identity column as the primary key for optimal insert performance.
2. Automatically generate an additional UUID column for data integrity across multiple databases.

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