Interview Q&A / System Design
System Design interview questions
Caching, scaling, databases and classic design problems for beginners.
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- How do you choose a good shard key?
A good shard key has high cardinality, spreads data and traffic evenly, and matches the most common query so requests hit one shard. Avoid keys that grow monotonically or are skewed, like timestamps or country.
IntermediateQuick answer1 min read - What is a hot partition and how do you fix it?
A hot partition is a shard or partition that receives far more traffic than the rest, so it becomes the bottleneck. Fix it with better keys, key salting, splitting the hot shard, or caching hot items.
IntermediateQuick answer1 min read