Databases · Senior · Question 25 of 75
What problems appear once data is sharded across databases?
- 1Indexes stop working
- 2SQL can no longer be used
- ✓Correct answer: Cross-shard joins and transactions become hard, global unique constraints aren't enforced, and rebalancing data is operationally complex
Explanation
That's why sharding is usually a last step after optimizing queries, adding replicas, caching and partitioning. Tools like Citus or Vitess hide part of the complexity.