Scaling Writes medium
In a sharded database, why is using a standard `AUTO_INCREMENT` integer as a Primary Key problematic?
- A It causes ID collisions. Two different shards might independently generate ID 105, preventing you from merging data later without conflicts.
- B Integers take up too much space.
- C SQL databases do not support integers.
- D It makes the URLs look ugly.
Answer: A. It causes ID collisions. Two different shards might independently generate ID 105, preventing you from merging data later without conflicts.
Centralized auto-increment requires a single coordinator (bottleneck). In sharded systems, you typically use algorithms like Snowflake (Timestamp + Machine ID) or UUIDs to generate unique IDs independently on each node.
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