Partitioning and Sharding at Scale | Dataford Interview Questions

Describe your experience with data partitioning and sharding strategies in large-scale databases.

Using the supplied shard metadata and event records, produce a distribution report that highlights uneven shard utilization. Treat events without an assigned shard as excluded from shard percentages.

Output

One row per configured shard, including shards with no events.
Columns: shard_id, shard_name, event_count, distinct_users, event_share_pct, and distribution_status.
Order by event_count descending, then shard_id ascending. Label shards above 40% as overloaded, below 10% as underutilized, and all others as balanced.

Schema

shards

Column	Type	Description
shard_idPK	INT	Unique identifier for a database shard
shard_name	VARCHAR(100)	Readable shard name
region	VARCHAR(50)	Deployment region for the shard

pin_events

Column	Type	Description
event_idPK	INT	Unique event identifier
shard_id	INT	Assigned database shard
user_id	INT	User associated with the event
event_type	VARCHAR(50)	Type of recorded event
event_date	DATE	Date when the event occurred

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Problem